Kernel/linux
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2024-12-29 17:23:36 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Browse Source 
Pull vfs mount infrastructure updates from Al Viro:
 "The rest of core infrastructure; no new syscalls in that pile, but the
  old parts are switched to new infrastructure. At that point
  conversions of individual filesystems can happen independently; some
  are done here (afs, cgroup, procfs, etc.), there's also a large series
  outside of that pile dealing with NFS (quite a bit of option-parsing
  stuff is getting used there - it's one of the most convoluted
  filesystems in terms of mount-related logics), but NFS bits are the
  next cycle fodder.

  It got seriously simplified since the last cycle; documentation is
  probably the weakest bit at the moment - I considered dropping the
  commit introducing Documentation/filesystems/mount_api.txt (cutting
  the size increase by quarter ;-), but decided that it would be better
  to fix it up after -rc1 instead.

  That pile allows to do followup work in independent branches, which
  should make life much easier for the next cycle. fs/super.c size
  increase is unpleasant; there's a followup series that allows to
  shrink it considerably, but I decided to leave that until the next
  cycle"

* 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (41 commits)
  afs: Use fs_context to pass parameters over automount
  afs: Add fs_context support
  vfs: Add some logging to the core users of the fs_context log
  vfs: Implement logging through fs_context
  vfs: Provide documentation for new mount API
  vfs: Remove kern_mount_data()
  hugetlbfs: Convert to fs_context
  cpuset: Use fs_context
  kernfs, sysfs, cgroup, intel_rdt: Support fs_context
  cgroup: store a reference to cgroup_ns into cgroup_fs_context
  cgroup1_get_tree(): separate "get cgroup_root to use" into a separate helper
  cgroup_do_mount(): massage calling conventions
  cgroup: stash cgroup_root reference into cgroup_fs_context
  cgroup2: switch to option-by-option parsing
  cgroup1: switch to option-by-option parsing
  cgroup: take options parsing into ->parse_monolithic()
  cgroup: fold cgroup1_mount() into cgroup1_get_tree()
  cgroup: start switching to fs_context
  ipc: Convert mqueue fs to fs_context
  proc: Add fs_context support to procfs
  ...
This commit is contained in:
Linus Torvalds 2019-03-12 14:08:19 -07:00
commit 7b47a9e7c8
45 changed files with 4377 additions and 1352 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

709
Documentation/filesystems/mount_api.txt Normal file
View File

@ -0,0 +1,709 @@
====================
FILESYSTEM MOUNT API
====================
CONTENTS
(1) Overview.
(2) The filesystem context.
(3) The filesystem context operations.
(4) Filesystem context security.
(5) VFS filesystem context operations.
(6) Parameter description.
(7) Parameter helper functions.
========
OVERVIEW
========
The creation of new mounts is now to be done in a multistep process:
(1) Create a filesystem context.
(2) Parse the parameters and attach them to the context. Parameters are
expected to be passed individually from userspace, though legacy binary
parameters can also be handled.
(3) Validate and pre-process the context.
(4) Get or create a superblock and mountable root.
(5) Perform the mount.
(6) Return an error message attached to the context.
(7) Destroy the context.
To support this, the file_system_type struct gains a new field:
int (*init_fs_context)(struct fs_context *fc);
which is invoked to set up the filesystem-specific parts of a filesystem
context, including the additional space.
Note that security initialisation is done *after* the filesystem is called so
that the namespaces may be adjusted first.
======================
THE FILESYSTEM CONTEXT
======================
The creation and reconfiguration of a superblock is governed by a filesystem
context. This is represented by the fs_context structure:
struct fs_context {
const struct fs_context_operations *ops;
struct file_system_type *fs_type;
void *fs_private;
struct dentry *root;
struct user_namespace *user_ns;
struct net *net_ns;
const struct cred *cred;
char *source;
char *subtype;
void *security;
void *s_fs_info;
unsigned int sb_flags;
unsigned int sb_flags_mask;
enum fs_context_purpose purpose:8;
bool sloppy:1;
bool silent:1;
...
};
The fs_context fields are as follows:
(*) const struct fs_context_operations *ops
These are operations that can be done on a filesystem context (see
below). This must be set by the ->init_fs_context() file_system_type
operation.
(*) struct file_system_type *fs_type
A pointer to the file_system_type of the filesystem that is being
constructed or reconfigured. This retains a reference on the type owner.
(*) void *fs_private
A pointer to the file system's private data. This is where the filesystem
will need to store any options it parses.
(*) struct dentry *root
A pointer to the root of the mountable tree (and indirectly, the
superblock thereof). This is filled in by the ->get_tree() op. If this
is set, an active reference on root->d_sb must also be held.
(*) struct user_namespace *user_ns
(*) struct net *net_ns
There are a subset of the namespaces in use by the invoking process. They
retain references on each namespace. The subscribed namespaces may be
replaced by the filesystem to reflect other sources, such as the parent
mount superblock on an automount.
(*) const struct cred *cred
The mounter's credentials. This retains a reference on the credentials.
(*) char *source
This specifies the source. It may be a block device (e.g. /dev/sda1) or
something more exotic, such as the "host:/path" that NFS desires.
(*) char *subtype
This is a string to be added to the type displayed in /proc/mounts to
qualify it (used by FUSE). This is available for the filesystem to set if
desired.
(*) void *security
A place for the LSMs to hang their security data for the superblock. The
relevant security operations are described below.
(*) void *s_fs_info
The proposed s_fs_info for a new superblock, set in the superblock by
sget_fc(). This can be used to distinguish superblocks.
(*) unsigned int sb_flags
(*) unsigned int sb_flags_mask
Which bits SB_* flags are to be set/cleared in super_block::s_flags.
(*) enum fs_context_purpose
This indicates the purpose for which the context is intended. The
available values are:
FS_CONTEXT_FOR_MOUNT, -- New superblock for explicit mount
FS_CONTEXT_FOR_SUBMOUNT -- New automatic submount of extant mount
FS_CONTEXT_FOR_RECONFIGURE -- Change an existing mount
(*) bool sloppy
(*) bool silent
These are set if the sloppy or silent mount options are given.
[NOTE] sloppy is probably unnecessary when userspace passes over one
option at a time since the error can just be ignored if userspace deems it
to be unimportant.
[NOTE] silent is probably redundant with sb_flags & SB_SILENT.
The mount context is created by calling vfs_new_fs_context() or
vfs_dup_fs_context() and is destroyed with put_fs_context(). Note that the
structure is not refcounted.
VFS, security and filesystem mount options are set individually with
vfs_parse_mount_option(). Options provided by the old mount(2) system call as
a page of data can be parsed with generic_parse_monolithic().
When mounting, the filesystem is allowed to take data from any of the pointers
and attach it to the superblock (or whatever), provided it clears the pointer
in the mount context.
The filesystem is also allowed to allocate resources and pin them with the
mount context. For instance, NFS might pin the appropriate protocol version
module.
=================================
THE FILESYSTEM CONTEXT OPERATIONS
=================================
The filesystem context points to a table of operations:
struct fs_context_operations {
void (*free)(struct fs_context *fc);
int (*dup)(struct fs_context *fc, struct fs_context *src_fc);
int (*parse_param)(struct fs_context *fc,
struct struct fs_parameter *param);
int (*parse_monolithic)(struct fs_context *fc, void *data);
int (*get_tree)(struct fs_context *fc);
int (*reconfigure)(struct fs_context *fc);
};
These operations are invoked by the various stages of the mount procedure to
manage the filesystem context. They are as follows:
(*) void (*free)(struct fs_context *fc);
Called to clean up the filesystem-specific part of the filesystem context
when the context is destroyed. It should be aware that parts of the
context may have been removed and NULL'd out by ->get_tree().
(*) int (*dup)(struct fs_context *fc, struct fs_context *src_fc);
Called when a filesystem context has been duplicated to duplicate the
filesystem-private data. An error may be returned to indicate failure to
do this.
[!] Note that even if this fails, put_fs_context() will be called
immediately thereafter, so ->dup() *must* make the
filesystem-private data safe for ->free().
(*) int (*parse_param)(struct fs_context *fc,
struct struct fs_parameter *param);
Called when a parameter is being added to the filesystem context. param
points to the key name and maybe a value object. VFS-specific options
will have been weeded out and fc->sb_flags updated in the context.
Security options will also have been weeded out and fc->security updated.
The parameter can be parsed with fs_parse() and fs_lookup_param(). Note
that the source(s) are presented as parameters named "source".
If successful, 0 should be returned or a negative error code otherwise.
(*) int (*parse_monolithic)(struct fs_context *fc, void *data);
Called when the mount(2) system call is invoked to pass the entire data
page in one go. If this is expected to be just a list of "key[=val]"
items separated by commas, then this may be set to NULL.
The return value is as for ->parse_param().
If the filesystem (e.g. NFS) needs to examine the data first and then
finds it's the standard key-val list then it may pass it off to
generic_parse_monolithic().
(*) int (*get_tree)(struct fs_context *fc);
Called to get or create the mountable root and superblock, using the
information stored in the filesystem context (reconfiguration goes via a
different vector). It may detach any resources it desires from the
filesystem context and transfer them to the superblock it creates.
On success it should set fc->root to the mountable root and return 0. In
the case of an error, it should return a negative error code.
The phase on a userspace-driven context will be set to only allow this to
be called once on any particular context.
(*) int (*reconfigure)(struct fs_context *fc);
Called to effect reconfiguration of a superblock using information stored
in the filesystem context. It may detach any resources it desires from
the filesystem context and transfer them to the superblock. The
superblock can be found from fc->root->d_sb.
On success it should return 0. In the case of an error, it should return
a negative error code.
[NOTE] reconfigure is intended as a replacement for remount_fs.
===========================
FILESYSTEM CONTEXT SECURITY
===========================
The filesystem context contains a security pointer that the LSMs can use for
building up a security context for the superblock to be mounted. There are a
number of operations used by the new mount code for this purpose:
(*) int security_fs_context_alloc(struct fs_context *fc,
struct dentry *reference);
Called to initialise fc->security (which is preset to NULL) and allocate
any resources needed. It should return 0 on success or a negative error
code on failure.
reference will be non-NULL if the context is being created for superblock
reconfiguration (FS_CONTEXT_FOR_RECONFIGURE) in which case it indicates
the root dentry of the superblock to be reconfigured. It will also be
non-NULL in the case of a submount (FS_CONTEXT_FOR_SUBMOUNT) in which case
it indicates the automount point.
(*) int security_fs_context_dup(struct fs_context *fc,
struct fs_context *src_fc);
Called to initialise fc->security (which is preset to NULL) and allocate
any resources needed. The original filesystem context is pointed to by
src_fc and may be used for reference. It should return 0 on success or a
negative error code on failure.
(*) void security_fs_context_free(struct fs_context *fc);
Called to clean up anything attached to fc->security. Note that the
contents may have been transferred to a superblock and the pointer cleared
during get_tree.
(*) int security_fs_context_parse_param(struct fs_context *fc,
struct fs_parameter *param);
Called for each mount parameter, including the source. The arguments are
as for the ->parse_param() method. It should return 0 to indicate that
the parameter should be passed on to the filesystem, 1 to indicate that
the parameter should be discarded or an error to indicate that the
parameter should be rejected.
The value pointed to by param may be modified (if a string) or stolen
(provided the value pointer is NULL'd out). If it is stolen, 1 must be
returned to prevent it being passed to the filesystem.
(*) int security_fs_context_validate(struct fs_context *fc);
Called after all the options have been parsed to validate the collection
as a whole and to do any necessary allocation so that
security_sb_get_tree() and security_sb_reconfigure() are less likely to
fail. It should return 0 or a negative error code.
In the case of reconfiguration, the target superblock will be accessible
via fc->root.
(*) int security_sb_get_tree(struct fs_context *fc);
Called during the mount procedure to verify that the specified superblock
is allowed to be mounted and to transfer the security data there. It
should return 0 or a negative error code.
(*) void security_sb_reconfigure(struct fs_context *fc);
Called to apply any reconfiguration to an LSM's context. It must not
fail. Error checking and resource allocation must be done in advance by
the parameter parsing and validation hooks.
(*) int security_sb_mountpoint(struct fs_context *fc, struct path *mountpoint,
unsigned int mnt_flags);
Called during the mount procedure to verify that the root dentry attached
to the context is permitted to be attached to the specified mountpoint.
It should return 0 on success or a negative error code on failure.
=================================
VFS FILESYSTEM CONTEXT OPERATIONS
=================================
There are four operations for creating a filesystem context and
one for destroying a context:
(*) struct fs_context *vfs_new_fs_context(struct file_system_type *fs_type,
struct dentry *reference,
unsigned int sb_flags,
unsigned int sb_flags_mask,
enum fs_context_purpose purpose);
Create a filesystem context for a given filesystem type and purpose. This
allocates the filesystem context, sets the superblock flags, initialises
the security and calls fs_type->init_fs_context() to initialise the
filesystem private data.
reference can be NULL or it may indicate the root dentry of a superblock
that is going to be reconfigured (FS_CONTEXT_FOR_RECONFIGURE) or
the automount point that triggered a submount (FS_CONTEXT_FOR_SUBMOUNT).
This is provided as a source of namespace information.
(*) struct fs_context *vfs_dup_fs_context(struct fs_context *src_fc);
Duplicate a filesystem context, copying any options noted and duplicating
or additionally referencing any resources held therein. This is available
for use where a filesystem has to get a mount within a mount, such as NFS4
does by internally mounting the root of the target server and then doing a
private pathwalk to the target directory.
The purpose in the new context is inherited from the old one.
(*) void put_fs_context(struct fs_context *fc);
Destroy a filesystem context, releasing any resources it holds. This
calls the ->free() operation. This is intended to be called by anyone who
created a filesystem context.
[!] filesystem contexts are not refcounted, so this causes unconditional
destruction.
In all the above operations, apart from the put op, the return is a mount
context pointer or a negative error code.
For the remaining operations, if an error occurs, a negative error code will be
returned.
(*) int vfs_get_tree(struct fs_context *fc);
Get or create the mountable root and superblock, using the parameters in
the filesystem context to select/configure the superblock. This invokes
the ->validate() op and then the ->get_tree() op.
[NOTE] ->validate() could perhaps be rolled into ->get_tree() and
->reconfigure().
(*) struct vfsmount *vfs_create_mount(struct fs_context *fc);
Create a mount given the parameters in the specified filesystem context.
Note that this does not attach the mount to anything.
(*) int vfs_parse_fs_param(struct fs_context *fc,
struct fs_parameter *param);
Supply a single mount parameter to the filesystem context. This include
the specification of the source/device which is specified as the "source"
parameter (which may be specified multiple times if the filesystem
supports that).
param specifies the parameter key name and the value. The parameter is
first checked to see if it corresponds to a standard mount flag (in which
case it is used to set an SB_xxx flag and consumed) or a security option
(in which case the LSM consumes it) before it is passed on to the
filesystem.
The parameter value is typed and can be one of:
fs_value_is_flag, Parameter not given a value.
fs_value_is_string, Value is a string
fs_value_is_blob, Value is a binary blob
fs_value_is_filename, Value is a filename* + dirfd
fs_value_is_filename_empty, Value is a filename* + dirfd + AT_EMPTY_PATH
fs_value_is_file, Value is an open file (file*)
If there is a value, that value is stored in a union in the struct in one
of param->{string,blob,name,file}. Note that the function may steal and
clear the pointer, but then becomes responsible for disposing of the
object.
(*) int vfs_parse_fs_string(struct fs_context *fc, char *key,
const char *value, size_t v_size);
A wrapper around vfs_parse_fs_param() that just passes a constant string.
(*) int generic_parse_monolithic(struct fs_context *fc, void *data);
Parse a sys_mount() data page, assuming the form to be a text list
consisting of key[=val] options separated by commas. Each item in the
list is passed to vfs_mount_option(). This is the default when the
->parse_monolithic() operation is NULL.
=====================
PARAMETER DESCRIPTION
=====================
Parameters are described using structures defined in linux/fs_parser.h.
There's a core description struct that links everything together:
struct fs_parameter_description {
const char name[16];
u8 nr_params;
u8 nr_alt_keys;
u8 nr_enums;
bool ignore_unknown;
bool no_source;
const char *const *keys;
const struct constant_table *alt_keys;
const struct fs_parameter_spec *specs;
const struct fs_parameter_enum *enums;
};
For example:
enum afs_param {
Opt_autocell,
Opt_bar,
Opt_dyn,
Opt_foo,
Opt_source,
nr__afs_params
};
static const struct fs_parameter_description afs_fs_parameters = {
.name = "kAFS",
.nr_params = nr__afs_params,
.nr_alt_keys = ARRAY_SIZE(afs_param_alt_keys),
.nr_enums = ARRAY_SIZE(afs_param_enums),
.keys = afs_param_keys,
.alt_keys = afs_param_alt_keys,
.specs = afs_param_specs,
.enums = afs_param_enums,
};
The members are as follows:
(1) const char name[16];
The name to be used in error messages generated by the parse helper
functions.
(2) u8 nr_params;
The number of discrete parameter identifiers. This indicates the number
of elements in the ->types[] array and also limits the values that may be
used in the values that the ->keys[] array maps to.
It is expected that, for example, two parameters that are related, say
"acl" and "noacl" with have the same ID, but will be flagged to indicate
that one is the inverse of the other. The value can then be picked out
from the parse result.
(3) const struct fs_parameter_specification *specs;
Table of parameter specifications, where the entries are of type:
struct fs_parameter_type {
enum fs_parameter_spec type:8;
u8 flags;
};
and the parameter identifier is the index to the array. 'type' indicates
the desired value type and must be one of:
TYPE NAME EXPECTED VALUE RESULT IN
======================= ======================= =====================
fs_param_is_flag No value n/a
fs_param_is_bool Boolean value result->boolean
fs_param_is_u32 32-bit unsigned int result->uint_32
fs_param_is_u32_octal 32-bit octal int result->uint_32
fs_param_is_u32_hex 32-bit hex int result->uint_32
fs_param_is_s32 32-bit signed int result->int_32
fs_param_is_enum Enum value name result->uint_32
fs_param_is_string Arbitrary string param->string
fs_param_is_blob Binary blob param->blob
fs_param_is_blockdev Blockdev path * Needs lookup
fs_param_is_path Path * Needs lookup
fs_param_is_fd File descriptor param->file
And each parameter can be qualified with 'flags':
fs_param_v_optional The value is optional
fs_param_neg_with_no If key name is prefixed with "no", it is false
fs_param_neg_with_empty If value is "", it is false
fs_param_deprecated The parameter is deprecated.
For example:
static const struct fs_parameter_spec afs_param_specs[nr__afs_params] = {
[Opt_autocell] = { fs_param_is flag },
[Opt_bar] = { fs_param_is_enum },
[Opt_dyn] = { fs_param_is flag },
[Opt_foo] = { fs_param_is_bool, fs_param_neg_with_no },
[Opt_source] = { fs_param_is_string },
};
Note that if the value is of fs_param_is_bool type, fs_parse() will try
to match any string value against "0", "1", "no", "yes", "false", "true".
[!] NOTE that the table must be sorted according to primary key name so
that ->keys[] is also sorted.
(4) const char *const *keys;
Table of primary key names for the parameters. There must be one entry
per defined parameter. The table is optional if ->nr_params is 0. The
table is just an array of names e.g.:
static const char *const afs_param_keys[nr__afs_params] = {
[Opt_autocell] = "autocell",
[Opt_bar] = "bar",
[Opt_dyn] = "dyn",
[Opt_foo] = "foo",
[Opt_source] = "source",
};
[!] NOTE that the table must be sorted such that the table can be searched
with bsearch() using strcmp(). This means that the Opt_* values must
correspond to the entries in this table.
(5) const struct constant_table *alt_keys;
u8 nr_alt_keys;
Table of additional key names and their mappings to parameter ID plus the
number of elements in the table. This is optional. The table is just an
array of { name, integer } pairs, e.g.:
static const struct constant_table afs_param_keys[] = {
{ "baz", Opt_bar },
{ "dynamic", Opt_dyn },
};
[!] NOTE that the table must be sorted such that strcmp() can be used with
bsearch() to search the entries.
The parameter ID can also be fs_param_key_removed to indicate that a
deprecated parameter has been removed and that an error will be given.
This differs from fs_param_deprecated where the parameter may still have
an effect.
Further, the behaviour of the parameter may differ when an alternate name
is used (for instance with NFS, "v3", "v4.2", etc. are alternate names).
(6) const struct fs_parameter_enum *enums;
u8 nr_enums;
Table of enum value names to integer mappings and the number of elements
stored therein. This is of type:
struct fs_parameter_enum {
u8 param_id;
char name[14];
u8 value;
};
Where the array is an unsorted list of { parameter ID, name }-keyed
elements that indicate the value to map to, e.g.:
static const struct fs_parameter_enum afs_param_enums[] = {
{ Opt_bar, "x", 1},
{ Opt_bar, "y", 23},
{ Opt_bar, "z", 42},
};
If a parameter of type fs_param_is_enum is encountered, fs_parse() will
try to look the value up in the enum table and the result will be stored
in the parse result.
(7) bool no_source;
If this is set, fs_parse() will ignore any "source" parameter and not
pass it to the filesystem.
The parser should be pointed to by the parser pointer in the file_system_type
struct as this will provide validation on registration (if
CONFIG_VALIDATE_FS_PARSER=y) and will allow the description to be queried from
userspace using the fsinfo() syscall.
==========================
PARAMETER HELPER FUNCTIONS
==========================
A number of helper functions are provided to help a filesystem or an LSM
process the parameters it is given.
(*) int lookup_constant(const struct constant_table tbl[],
const char *name, int not_found);
Look up a constant by name in a table of name -> integer mappings. The
table is an array of elements of the following type:
struct constant_table {
const char *name;
int value;
};
and it must be sorted such that it can be searched using bsearch() using
strcmp(). If a match is found, the corresponding value is returned. If a
match isn't found, the not_found value is returned instead.
(*) bool validate_constant_table(const struct constant_table *tbl,
size_t tbl_size,
int low, int high, int special);
Validate a constant table. Checks that all the elements are appropriately
ordered, that there are no duplicates and that the values are between low
and high inclusive, though provision is made for one allowable special
value outside of that range. If no special value is required, special
should just be set to lie inside the low-to-high range.
If all is good, true is returned. If the table is invalid, errors are
logged to dmesg, the stack is dumped and false is returned.
(*) int fs_parse(struct fs_context *fc,
const struct fs_param_parser *parser,
struct fs_parameter *param,
struct fs_param_parse_result *result);
This is the main interpreter of parameters. It uses the parameter
description (parser) to look up the name of the parameter to use and to
convert that to a parameter ID (stored in result->key).
If successful, and if the parameter type indicates the result is a
boolean, integer or enum type, the value is converted by this function and
the result stored in result->{boolean,int_32,uint_32}.
If a match isn't initially made, the key is prefixed with "no" and no
value is present then an attempt will be made to look up the key with the
prefix removed. If this matches a parameter for which the type has flag
fs_param_neg_with_no set, then a match will be made and the value will be
set to false/0/NULL.
If the parameter is successfully matched and, optionally, parsed
correctly, 1 is returned. If the parameter isn't matched and
parser->ignore_unknown is set, then 0 is returned. Otherwise -EINVAL is
returned.
(*) bool fs_validate_description(const struct fs_parameter_description *desc);
This is validates the parameter description. It returns true if the
description is good and false if it is not.
(*) int fs_lookup_param(struct fs_context *fc,
struct fs_parameter *value,
bool want_bdev,
struct path *_path);
This takes a parameter that carries a string or filename type and attempts
to do a path lookup on it. If the parameter expects a blockdev, a check
is made that the inode actually represents one.
Returns 0 if successful and *_path will be set; returns a negative error
code if not.

16
arch/x86/kernel/cpu/resctrl/internal.h
View File

@ -4,6 +4,7 @@
#include <linux/sched.h>
#include <linux/kernfs.h>
#include <linux/fs_context.h>
#include <linux/jump_label.h>
#define MSR_IA32_L3_QOS_CFG 0xc81
@ -40,6 +41,21 @@
#define RMID_VAL_ERROR BIT_ULL(63)
#define RMID_VAL_UNAVAIL BIT_ULL(62)
struct rdt_fs_context {
struct kernfs_fs_context kfc;
bool enable_cdpl2;
bool enable_cdpl3;
bool enable_mba_mbps;
};
static inline struct rdt_fs_context *rdt_fc2context(struct fs_context *fc)
{
struct kernfs_fs_context *kfc = fc->fs_private;
return container_of(kfc, struct rdt_fs_context, kfc);
}
DECLARE_STATIC_KEY_FALSE(rdt_enable_key);
/**

185
arch/x86/kernel/cpu/resctrl/rdtgroup.c
View File

@ -24,6 +24,7 @@
#include <linux/cpu.h>
#include <linux/debugfs.h>
#include <linux/fs.h>
#include <linux/fs_parser.h>
#include <linux/sysfs.h>
#include <linux/kernfs.h>
#include <linux/seq_buf.h>
@ -32,6 +33,7 @@
#include <linux/sched/task.h>
#include <linux/slab.h>
#include <linux/task_work.h>
#include <linux/user_namespace.h>
#include <uapi/linux/magic.h>
@ -1858,46 +1860,6 @@ static void cdp_disable_all(void)
cdpl2_disable();
}
static int parse_rdtgroupfs_options(char *data)
{
char *token, *o = data;
int ret = 0;
while ((token = strsep(&o, ",")) != NULL) {
if (!*token) {
ret = -EINVAL;
goto out;
}
if (!strcmp(token, "cdp")) {
ret = cdpl3_enable();
if (ret)
goto out;
} else if (!strcmp(token, "cdpl2")) {
ret = cdpl2_enable();
if (ret)
goto out;
} else if (!strcmp(token, "mba_MBps")) {
if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
ret = set_mba_sc(true);
else
ret = -EINVAL;
if (ret)
goto out;
} else {
ret = -EINVAL;
goto out;
}
}
return 0;
out:
pr_err("Invalid mount option \"%s\"\n", token);
return ret;
}
/*
* We don't allow rdtgroup directories to be created anywhere
* except the root directory. Thus when looking for the rdtgroup
@ -1969,13 +1931,27 @@ static int mkdir_mondata_all(struct kernfs_node *parent_kn,
struct rdtgroup *prgrp,
struct kernfs_node **mon_data_kn);
static struct dentry *rdt_mount(struct file_system_type *fs_type,
int flags, const char *unused_dev_name,
void *data)
static int rdt_enable_ctx(struct rdt_fs_context *ctx)
{
int ret = 0;
if (ctx->enable_cdpl2)
ret = cdpl2_enable();
if (!ret && ctx->enable_cdpl3)
ret = cdpl3_enable();
if (!ret && ctx->enable_mba_mbps)
ret = set_mba_sc(true);
return ret;
}
static int rdt_get_tree(struct fs_context *fc)
{
struct rdt_fs_context *ctx = rdt_fc2context(fc);
struct rdt_domain *dom;
struct rdt_resource *r;
struct dentry *dentry;
int ret;
cpus_read_lock();
@ -1984,53 +1960,42 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type,
* resctrl file system can only be mounted once.
*/
if (static_branch_unlikely(&rdt_enable_key)) {
dentry = ERR_PTR(-EBUSY);
ret = -EBUSY;
goto out;
}
ret = parse_rdtgroupfs_options(data);
if (ret) {
dentry = ERR_PTR(ret);
ret = rdt_enable_ctx(ctx);
if (ret < 0)
goto out_cdp;
}
closid_init();
ret = rdtgroup_create_info_dir(rdtgroup_default.kn);
if (ret) {
dentry = ERR_PTR(ret);
goto out_cdp;
}
if (ret < 0)
goto out_mba;
if (rdt_mon_capable) {
ret = mongroup_create_dir(rdtgroup_default.kn,
NULL, "mon_groups",
&kn_mongrp);
if (ret) {
dentry = ERR_PTR(ret);
if (ret < 0)
goto out_info;
}
kernfs_get(kn_mongrp);
ret = mkdir_mondata_all(rdtgroup_default.kn,
&rdtgroup_default, &kn_mondata);
if (ret) {
dentry = ERR_PTR(ret);
if (ret < 0)
goto out_mongrp;
}
kernfs_get(kn_mondata);
rdtgroup_default.mon.mon_data_kn = kn_mondata;
}
ret = rdt_pseudo_lock_init();
if (ret) {
dentry = ERR_PTR(ret);
if (ret)
goto out_mondata;
}
dentry = kernfs_mount(fs_type, flags, rdt_root,
RDTGROUP_SUPER_MAGIC, NULL);
if (IS_ERR(dentry))
ret = kernfs_get_tree(fc);
if (ret < 0)
goto out_psl;
if (rdt_alloc_capable)
@ -2059,14 +2024,95 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type,
kernfs_remove(kn_mongrp);
out_info:
kernfs_remove(kn_info);
out_mba:
if (ctx->enable_mba_mbps)
set_mba_sc(false);
out_cdp:
cdp_disable_all();
out:
rdt_last_cmd_clear();
mutex_unlock(&rdtgroup_mutex);
cpus_read_unlock();
return ret;
}
return dentry;
enum rdt_param {
Opt_cdp,
Opt_cdpl2,
Opt_mba_mpbs,
nr__rdt_params
};
static const struct fs_parameter_spec rdt_param_specs[] = {
fsparam_flag("cdp", Opt_cdp),
fsparam_flag("cdpl2", Opt_cdpl2),
fsparam_flag("mba_mpbs", Opt_mba_mpbs),
{}
};
static const struct fs_parameter_description rdt_fs_parameters = {
.name = "rdt",
.specs = rdt_param_specs,
};
static int rdt_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
struct rdt_fs_context *ctx = rdt_fc2context(fc);
struct fs_parse_result result;
int opt;
opt = fs_parse(fc, &rdt_fs_parameters, param, &result);
if (opt < 0)
return opt;
switch (opt) {
case Opt_cdp:
ctx->enable_cdpl3 = true;
return 0;
case Opt_cdpl2:
ctx->enable_cdpl2 = true;
return 0;
case Opt_mba_mpbs:
if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
return -EINVAL;
ctx->enable_mba_mbps = true;
return 0;
}
return -EINVAL;
}
static void rdt_fs_context_free(struct fs_context *fc)
{
struct rdt_fs_context *ctx = rdt_fc2context(fc);
kernfs_free_fs_context(fc);
kfree(ctx);
}
static const struct fs_context_operations rdt_fs_context_ops = {
.free = rdt_fs_context_free,
.parse_param = rdt_parse_param,
.get_tree = rdt_get_tree,
};
static int rdt_init_fs_context(struct fs_context *fc)
{
struct rdt_fs_context *ctx;
ctx = kzalloc(sizeof(struct rdt_fs_context), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->kfc.root = rdt_root;
ctx->kfc.magic = RDTGROUP_SUPER_MAGIC;
fc->fs_private = &ctx->kfc;
fc->ops = &rdt_fs_context_ops;
if (fc->user_ns)
put_user_ns(fc->user_ns);
fc->user_ns = get_user_ns(&init_user_ns);
fc->global = true;
return 0;
}
static int reset_all_ctrls(struct rdt_resource *r)
@ -2239,9 +2285,10 @@ static void rdt_kill_sb(struct super_block *sb)
}
static struct file_system_type rdt_fs_type = {
.name = "resctrl",
.mount = rdt_mount,
.kill_sb = rdt_kill_sb,
.name = "resctrl",
.init_fs_context = rdt_init_fs_context,
.parameters = &rdt_fs_parameters,
.kill_sb = rdt_kill_sb,
};
static int mon_addfile(struct kernfs_node *parent_kn, const char *name,

7
fs/Kconfig
View File

@ -8,6 +8,13 @@ menu "File systems"
config DCACHE_WORD_ACCESS
bool
config VALIDATE_FS_PARSER
bool "Validate filesystem parameter description"
default y
help
Enable this to perform validation of the parameter description for a
filesystem when it is registered.
if BLOCK
config FS_IOMAP

2
fs/Makefile
View File

@ -13,7 +13,7 @@ obj-y := open.o read_write.o file_table.o super.o \
seq_file.o xattr.o libfs.o fs-writeback.o \
pnode.o splice.o sync.o utimes.o d_path.o \
stack.o fs_struct.o statfs.o fs_pin.o nsfs.o \
fs_types.o
fs_types.o fs_context.o fs_parser.o
ifeq ($(CONFIG_BLOCK),y)
obj-y += buffer.o block_dev.o direct-io.o mpage.o

9
fs/afs/internal.h
View File

@ -36,15 +36,14 @@
struct pagevec;
struct afs_call;
struct afs_mount_params {
bool rwpath; /* T if the parent should be considered R/W */
struct afs_fs_context {
bool force; /* T to force cell type */
bool autocell; /* T if set auto mount operation */
bool dyn_root; /* T if dynamic root */
bool no_cell; /* T if the source is "none" (for dynroot) */
afs_voltype_t type; /* type of volume requested */
int volnamesz; /* size of volume name */
unsigned int volnamesz; /* size of volume name */
const char *volname; /* name of volume to mount */
struct net *net_ns; /* Network namespace in effect */
struct afs_net *net; /* the AFS net namespace stuff */
struct afs_cell *cell; /* cell in which to find volume */
struct afs_volume *volume; /* volume record */
@ -1274,7 +1273,7 @@ static inline struct afs_volume *__afs_get_volume(struct afs_volume *volume)
return volume;
}
extern struct afs_volume *afs_create_volume(struct afs_mount_params *);
extern struct afs_volume *afs_create_volume(struct afs_fs_context *);
extern void afs_activate_volume(struct afs_volume *);
extern void afs_deactivate_volume(struct afs_volume *);
extern void afs_put_volume(struct afs_cell *, struct afs_volume *);

187
fs/afs/mntpt.c
View File

@ -17,6 +17,7 @@
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/gfp.h>
#include <linux/fs_context.h>
#include "internal.h"
@ -47,6 +48,8 @@ static DECLARE_DELAYED_WORK(afs_mntpt_expiry_timer, afs_mntpt_expiry_timed_out);
static unsigned long afs_mntpt_expiry_timeout = 10 * 60;
static const char afs_root_volume[] = "root.cell";
/*
* no valid lookup procedure on this sort of dir
*/
@ -67,109 +70,113 @@ static int afs_mntpt_open(struct inode *inode, struct file *file)
return -EREMOTE;
}
/*
* Set the parameters for the proposed superblock.
*/
static int afs_mntpt_set_params(struct fs_context *fc, struct dentry *mntpt)
{
struct afs_fs_context *ctx = fc->fs_private;
struct afs_super_info *src_as = AFS_FS_S(mntpt->d_sb);
struct afs_vnode *vnode = AFS_FS_I(d_inode(mntpt));
struct afs_cell *cell;
const char *p;
int ret;
if (fc->net_ns != src_as->net_ns) {
put_net(fc->net_ns);
fc->net_ns = get_net(src_as->net_ns);
}
if (src_as->volume && src_as->volume->type == AFSVL_RWVOL) {
ctx->type = AFSVL_RWVOL;
ctx->force = true;
}
if (ctx->cell) {
afs_put_cell(ctx->net, ctx->cell);
ctx->cell = NULL;
}
if (test_bit(AFS_VNODE_PSEUDODIR, &vnode->flags)) {
/* if the directory is a pseudo directory, use the d_name */
unsigned size = mntpt->d_name.len;
if (size < 2)
return -ENOENT;
p = mntpt->d_name.name;
if (mntpt->d_name.name[0] == '.') {
size--;
p++;
ctx->type = AFSVL_RWVOL;
ctx->force = true;
}
if (size > AFS_MAXCELLNAME)
return -ENAMETOOLONG;
cell = afs_lookup_cell(ctx->net, p, size, NULL, false);
if (IS_ERR(cell)) {
pr_err("kAFS: unable to lookup cell '%pd'\n", mntpt);
return PTR_ERR(cell);
}
ctx->cell = cell;
ctx->volname = afs_root_volume;
ctx->volnamesz = sizeof(afs_root_volume) - 1;
} else {
/* read the contents of the AFS special symlink */
struct page *page;
loff_t size = i_size_read(d_inode(mntpt));
char *buf;
if (src_as->cell)
ctx->cell = afs_get_cell(src_as->cell);
if (size > PAGE_SIZE - 1)
return -EINVAL;
page = read_mapping_page(d_inode(mntpt)->i_mapping, 0, NULL);
if (IS_ERR(page))
return PTR_ERR(page);
if (PageError(page)) {
ret = afs_bad(AFS_FS_I(d_inode(mntpt)), afs_file_error_mntpt);
put_page(page);
return ret;
}
buf = kmap(page);
ret = vfs_parse_fs_string(fc, "source", buf, size);
kunmap(page);
put_page(page);
if (ret < 0)
return ret;
}
return 0;
}
/*
* create a vfsmount to be automounted
*/
static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt)
{
struct afs_super_info *as;
struct fs_context *fc;
struct vfsmount *mnt;
struct afs_vnode *vnode;
struct page *page;
char *devname, *options;
bool rwpath = false;
int ret;
_enter("{%pd}", mntpt);
BUG_ON(!d_inode(mntpt));
ret = -ENOMEM;
devname = (char *) get_zeroed_page(GFP_KERNEL);
if (!devname)
goto error_no_devname;
fc = fs_context_for_submount(&afs_fs_type, mntpt);
if (IS_ERR(fc))
return ERR_CAST(fc);
options = (char *) get_zeroed_page(GFP_KERNEL);
if (!options)
goto error_no_options;
ret = afs_mntpt_set_params(fc, mntpt);
if (!ret)
mnt = fc_mount(fc);
else
mnt = ERR_PTR(ret);
vnode = AFS_FS_I(d_inode(mntpt));
if (test_bit(AFS_VNODE_PSEUDODIR, &vnode->flags)) {
/* if the directory is a pseudo directory, use the d_name */
static const char afs_root_cell[] = ":root.cell.";
unsigned size = mntpt->d_name.len;
ret = -ENOENT;
if (size < 2 || size > AFS_MAXCELLNAME)
goto error_no_page;
if (mntpt->d_name.name[0] == '.') {
devname[0] = '%';
memcpy(devname + 1, mntpt->d_name.name + 1, size - 1);
memcpy(devname + size, afs_root_cell,
sizeof(afs_root_cell));
rwpath = true;
} else {
devname[0] = '#';
memcpy(devname + 1, mntpt->d_name.name, size);
memcpy(devname + size + 1, afs_root_cell,
sizeof(afs_root_cell));
}
} else {
/* read the contents of the AFS special symlink */
loff_t size = i_size_read(d_inode(mntpt));
char *buf;
ret = -EINVAL;
if (size > PAGE_SIZE - 1)
goto error_no_page;
page = read_mapping_page(d_inode(mntpt)->i_mapping, 0, NULL);
if (IS_ERR(page)) {
ret = PTR_ERR(page);
goto error_no_page;
}
if (PageError(page)) {
ret = afs_bad(AFS_FS_I(d_inode(mntpt)), afs_file_error_mntpt);
goto error;
}
buf = kmap_atomic(page);
memcpy(devname, buf, size);
kunmap_atomic(buf);
put_page(page);
page = NULL;
}
/* work out what options we want */
as = AFS_FS_S(mntpt->d_sb);
if (as->cell) {
memcpy(options, "cell=", 5);
strcpy(options + 5, as->cell->name);
if ((as->volume && as->volume->type == AFSVL_RWVOL) || rwpath)
strcat(options, ",rwpath");
}
/* try and do the mount */
_debug("--- attempting mount %s -o %s ---", devname, options);
mnt = vfs_submount(mntpt, &afs_fs_type, devname, options);
_debug("--- mount result %p ---", mnt);
free_page((unsigned long) devname);
free_page((unsigned long) options);
_leave(" = %p", mnt);
put_fs_context(fc);
return mnt;
error:
put_page(page);
error_no_page:
free_page((unsigned long) options);
error_no_options:
free_page((unsigned long) devname);
error_no_devname:
_leave(" = %d", ret);
return ERR_PTR(ret);
}
/*

430
fs/afs/super.c
View File

@ -1,6 +1,6 @@
/* AFS superblock handling
*
* Copyright (c) 2002, 2007 Red Hat, Inc. All rights reserved.
* Copyright (c) 2002, 2007, 2018 Red Hat, Inc. All rights reserved.
*
* This software may be freely redistributed under the terms of the
* GNU General Public License.
@ -21,7 +21,7 @@
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/parser.h>
#include <linux/fs_parser.h>
#include <linux/statfs.h>
#include <linux/sched.h>
#include <linux/nsproxy.h>
@ -30,21 +30,22 @@
#include "internal.h"
static void afs_i_init_once(void *foo);
static struct dentry *afs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data);
static void afs_kill_super(struct super_block *sb);
static struct inode *afs_alloc_inode(struct super_block *sb);
static void afs_destroy_inode(struct inode *inode);
static int afs_statfs(struct dentry *dentry, struct kstatfs *buf);
static int afs_show_devname(struct seq_file *m, struct dentry *root);
static int afs_show_options(struct seq_file *m, struct dentry *root);
static int afs_init_fs_context(struct fs_context *fc);
static const struct fs_parameter_description afs_fs_parameters;
struct file_system_type afs_fs_type = {
.owner = THIS_MODULE,
.name = "afs",
.mount = afs_mount,
.kill_sb = afs_kill_super,
.fs_flags = 0,
.owner = THIS_MODULE,
.name = "afs",
.init_fs_context = afs_init_fs_context,
.parameters = &afs_fs_parameters,
.kill_sb = afs_kill_super,
.fs_flags = 0,
};
MODULE_ALIAS_FS("afs");
@ -63,22 +64,22 @@ static const struct super_operations afs_super_ops = {
static struct kmem_cache *afs_inode_cachep;
static atomic_t afs_count_active_inodes;
enum {
afs_no_opt,
afs_opt_cell,
afs_opt_dyn,
afs_opt_rwpath,
afs_opt_vol,
afs_opt_autocell,
enum afs_param {
Opt_autocell,
Opt_dyn,
Opt_source,
};
static const match_table_t afs_options_list = {
{ afs_opt_cell, "cell=%s" },
{ afs_opt_dyn, "dyn" },
{ afs_opt_rwpath, "rwpath" },
{ afs_opt_vol, "vol=%s" },
{ afs_opt_autocell, "autocell" },
{ afs_no_opt, NULL },
static const struct fs_parameter_spec afs_param_specs[] = {
fsparam_flag ("autocell", Opt_autocell),
fsparam_flag ("dyn", Opt_dyn),
fsparam_string("source", Opt_source),
{}
};
static const struct fs_parameter_description afs_fs_parameters = {
.name = "kAFS",
.specs = afs_param_specs,
};
/*
@ -190,84 +191,23 @@ static int afs_show_options(struct seq_file *m, struct dentry *root)
}
/*
* parse the mount options
* - this function has been shamelessly adapted from the ext3 fs which
* shamelessly adapted it from the msdos fs
*/
static int afs_parse_options(struct afs_mount_params *params,
char *options, const char **devname)
{
struct afs_cell *cell;
substring_t args[MAX_OPT_ARGS];
char *p;
int token;
_enter("%s", options);
options[PAGE_SIZE - 1] = 0;
while ((p = strsep(&options, ","))) {
if (!*p)
continue;
token = match_token(p, afs_options_list, args);
switch (token) {
case afs_opt_cell:
rcu_read_lock();
cell = afs_lookup_cell_rcu(params->net,
args[0].from,
args[0].to - args[0].from);
rcu_read_unlock();
if (IS_ERR(cell))
return PTR_ERR(cell);
afs_put_cell(params->net, params->cell);
params->cell = cell;
break;
case afs_opt_rwpath:
params->rwpath = true;
break;
case afs_opt_vol:
*devname = args[0].from;
break;
case afs_opt_autocell:
params->autocell = true;
break;
case afs_opt_dyn:
params->dyn_root = true;
break;
default:
printk(KERN_ERR "kAFS:"
" Unknown or invalid mount option: '%s'\n", p);
return -EINVAL;
}
}
_leave(" = 0");
return 0;
}
/*
* parse a device name to get cell name, volume name, volume type and R/W
* selector
* - this can be one of the following:
* Parse the source name to get cell name, volume name, volume type and R/W
* selector.
*
* This can be one of the following:
* "%[cell:]volume[.]" R/W volume
* "#[cell:]volume[.]" R/O or R/W volume (rwpath=0),
* or R/W (rwpath=1) volume
* "#[cell:]volume[.]" R/O or R/W volume (R/O parent),
* or R/W (R/W parent) volume
* "%[cell:]volume.readonly" R/O volume
* "#[cell:]volume.readonly" R/O volume
* "%[cell:]volume.backup" Backup volume
* "#[cell:]volume.backup" Backup volume
*/
static int afs_parse_device_name(struct afs_mount_params *params,
const char *name)
static int afs_parse_source(struct fs_context *fc, struct fs_parameter *param)
{
struct afs_fs_context *ctx = fc->fs_private;
struct afs_cell *cell;
const char *cellname, *suffix;
const char *cellname, *suffix, *name = param->string;
int cellnamesz;
_enter(",%s", name);
@ -278,69 +218,149 @@ static int afs_parse_device_name(struct afs_mount_params *params,
}
if ((name[0] != '%' && name[0] != '#') || !name[1]) {
/* To use dynroot, we don't want to have to provide a source */
if (strcmp(name, "none") == 0) {
ctx->no_cell = true;
return 0;
}
printk(KERN_ERR "kAFS: unparsable volume name\n");
return -EINVAL;
}
/* determine the type of volume we're looking for */
params->type = AFSVL_ROVOL;
params->force = false;
if (params->rwpath || name[0] == '%') {
params->type = AFSVL_RWVOL;
params->force = true;
if (name[0] == '%') {
ctx->type = AFSVL_RWVOL;
ctx->force = true;
}
name++;
/* split the cell name out if there is one */
params->volname = strchr(name, ':');
if (params->volname) {
ctx->volname = strchr(name, ':');
if (ctx->volname) {
cellname = name;
cellnamesz = params->volname - name;
params->volname++;
cellnamesz = ctx->volname - name;
ctx->volname++;
} else {
params->volname = name;
ctx->volname = name;
cellname = NULL;
cellnamesz = 0;
}
/* the volume type is further affected by a possible suffix */
suffix = strrchr(params->volname, '.');
suffix = strrchr(ctx->volname, '.');
if (suffix) {
if (strcmp(suffix, ".readonly") == 0) {
params->type = AFSVL_ROVOL;
params->force = true;
ctx->type = AFSVL_ROVOL;
ctx->force = true;
} else if (strcmp(suffix, ".backup") == 0) {
params->type = AFSVL_BACKVOL;
params->force = true;
ctx->type = AFSVL_BACKVOL;
ctx->force = true;
} else if (suffix[1] == 0) {
} else {
suffix = NULL;
}
}
params->volnamesz = suffix ?
suffix - params->volname : strlen(params->volname);
ctx->volnamesz = suffix ?
suffix - ctx->volname : strlen(ctx->volname);
_debug("cell %*.*s [%p]",
cellnamesz, cellnamesz, cellname ?: "", params->cell);
cellnamesz, cellnamesz, cellname ?: "", ctx->cell);
/* lookup the cell record */
if (cellname || !params->cell) {
cell = afs_lookup_cell(params->net, cellname, cellnamesz,
if (cellname) {
cell = afs_lookup_cell(ctx->net, cellname, cellnamesz,
NULL, false);
if (IS_ERR(cell)) {
printk(KERN_ERR "kAFS: unable to lookup cell '%*.*s'\n",
pr_err("kAFS: unable to lookup cell '%*.*s'\n",
cellnamesz, cellnamesz, cellname ?: "");
return PTR_ERR(cell);
}
afs_put_cell(params->net, params->cell);
params->cell = cell;
afs_put_cell(ctx->net, ctx->cell);
ctx->cell = cell;
}
_debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
params->cell->name, params->cell,
params->volnamesz, params->volnamesz, params->volname,
suffix ?: "-", params->type, params->force ? " FORCE" : "");
ctx->cell->name, ctx->cell,
ctx->volnamesz, ctx->volnamesz, ctx->volname,
suffix ?: "-", ctx->type, ctx->force ? " FORCE" : "");
fc->source = param->string;
param->string = NULL;
return 0;
}
/*
* Parse a single mount parameter.
*/
static int afs_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
struct fs_parse_result result;
struct afs_fs_context *ctx = fc->fs_private;
int opt;
opt = fs_parse(fc, &afs_fs_parameters, param, &result);
if (opt < 0)
return opt;
switch (opt) {
case Opt_source:
return afs_parse_source(fc, param);
case Opt_autocell:
ctx->autocell = true;
break;
case Opt_dyn:
ctx->dyn_root = true;
break;
default:
return -EINVAL;
}
_leave(" = 0");
return 0;
}
/*
* Validate the options, get the cell key and look up the volume.
*/
static int afs_validate_fc(struct fs_context *fc)
{
struct afs_fs_context *ctx = fc->fs_private;
struct afs_volume *volume;
struct key *key;
if (!ctx->dyn_root) {
if (ctx->no_cell) {
pr_warn("kAFS: Can only specify source 'none' with -o dyn\n");
return -EINVAL;
}
if (!ctx->cell) {
pr_warn("kAFS: No cell specified\n");
return -EDESTADDRREQ;
}
/* We try to do the mount securely. */
key = afs_request_key(ctx->cell);
if (IS_ERR(key))
return PTR_ERR(key);
ctx->key = key;
if (ctx->volume) {
afs_put_volume(ctx->cell, ctx->volume);
ctx->volume = NULL;
}
volume = afs_create_volume(ctx);
if (IS_ERR(volume))
return PTR_ERR(volume);
ctx->volume = volume;
}
return 0;
}
@ -348,39 +368,34 @@ static int afs_parse_device_name(struct afs_mount_params *params,
/*
* check a superblock to see if it's the one we're looking for
*/
static int afs_test_super(struct super_block *sb, void *data)
static int afs_test_super(struct super_block *sb, struct fs_context *fc)
{
struct afs_super_info *as1 = data;
struct afs_fs_context *ctx = fc->fs_private;
struct afs_super_info *as = AFS_FS_S(sb);
return (as->net_ns == as1->net_ns &&
return (as->net_ns == fc->net_ns &&
as->volume &&
as->volume->vid == as1->volume->vid &&
as->volume->vid == ctx->volume->vid &&
!as->dyn_root);
}
static int afs_dynroot_test_super(struct super_block *sb, void *data)
static int afs_dynroot_test_super(struct super_block *sb, struct fs_context *fc)
{
struct afs_super_info *as1 = data;
struct afs_super_info *as = AFS_FS_S(sb);
return (as->net_ns == as1->net_ns &&
return (as->net_ns == fc->net_ns &&
as->dyn_root);
}
static int afs_set_super(struct super_block *sb, void *data)
static int afs_set_super(struct super_block *sb, struct fs_context *fc)
{
struct afs_super_info *as = data;
sb->s_fs_info = as;
return set_anon_super(sb, NULL);
}
/*
* fill in the superblock
*/
static int afs_fill_super(struct super_block *sb,
struct afs_mount_params *params)
static int afs_fill_super(struct super_block *sb, struct afs_fs_context *ctx)
{
struct afs_super_info *as = AFS_FS_S(sb);
struct afs_fid fid;
@ -412,13 +427,13 @@ static int afs_fill_super(struct super_block *sb,
fid.vnode = 1;
fid.vnode_hi = 0;
fid.unique = 1;
inode = afs_iget(sb, params->key, &fid, NULL, NULL, NULL);
inode = afs_iget(sb, ctx->key, &fid, NULL, NULL, NULL);
}
if (IS_ERR(inode))
return PTR_ERR(inode);
if (params->autocell || params->dyn_root)
if (ctx->autocell || as->dyn_root)
set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
ret = -ENOMEM;
@ -443,17 +458,20 @@ static int afs_fill_super(struct super_block *sb,
return ret;
}
static struct afs_super_info *afs_alloc_sbi(struct afs_mount_params *params)
static struct afs_super_info *afs_alloc_sbi(struct fs_context *fc)
{
struct afs_fs_context *ctx = fc->fs_private;
struct afs_super_info *as;
as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
if (as) {
as->net_ns = get_net(params->net_ns);
if (params->dyn_root)
as->net_ns = get_net(fc->net_ns);
if (ctx->dyn_root) {
as->dyn_root = true;
else
as->cell = afs_get_cell(params->cell);
} else {
as->cell = afs_get_cell(ctx->cell);
as->volume = __afs_get_volume(ctx->volume);
}
}
return as;
}
@ -475,7 +493,7 @@ static void afs_kill_super(struct super_block *sb)
if (as->dyn_root)
afs_dynroot_depopulate(sb);
/* Clear the callback interests (which will do ilookup5) before
* deactivating the superblock.
*/
@ -488,111 +506,103 @@ static void afs_kill_super(struct super_block *sb)
}
/*
* get an AFS superblock
* Get an AFS superblock and root directory.
*/
static struct dentry *afs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *options)
static int afs_get_tree(struct fs_context *fc)
{
struct afs_mount_params params;
struct afs_fs_context *ctx = fc->fs_private;
struct super_block *sb;
struct afs_volume *candidate;
struct key *key;
struct afs_super_info *as;
int ret;
_enter(",,%s,%p", dev_name, options);
memset(&params, 0, sizeof(params));
ret = -EINVAL;
if (current->nsproxy->net_ns != &init_net)
ret = afs_validate_fc(fc);
if (ret)
goto error;
params.net_ns = current->nsproxy->net_ns;
params.net = afs_net(params.net_ns);
/* parse the options and device name */
if (options) {
ret = afs_parse_options(&params, options, &dev_name);
if (ret < 0)
goto error;
}
if (!params.dyn_root) {
ret = afs_parse_device_name(&params, dev_name);
if (ret < 0)
goto error;
/* try and do the mount securely */
key = afs_request_key(params.cell);
if (IS_ERR(key)) {
_leave(" = %ld [key]", PTR_ERR(key));
ret = PTR_ERR(key);
goto error;
}
params.key = key;
}
_enter("");
/* allocate a superblock info record */
ret = -ENOMEM;
as = afs_alloc_sbi(&params);
as = afs_alloc_sbi(fc);
if (!as)
goto error_key;
if (!params.dyn_root) {
/* Assume we're going to need a volume record; at the very
* least we can use it to update the volume record if we have
* one already. This checks that the volume exists within the
* cell.
*/
candidate = afs_create_volume(&params);
if (IS_ERR(candidate)) {
ret = PTR_ERR(candidate);
goto error_as;
}
as->volume = candidate;
}
goto error;
fc->s_fs_info = as;
/* allocate a deviceless superblock */
sb = sget(fs_type,
as->dyn_root ? afs_dynroot_test_super : afs_test_super,
afs_set_super, flags, as);
sb = sget_fc(fc,
as->dyn_root ? afs_dynroot_test_super : afs_test_super,
afs_set_super);
if (IS_ERR(sb)) {
ret = PTR_ERR(sb);
goto error_as;
goto error;
}
if (!sb->s_root) {
/* initial superblock/root creation */
_debug("create");
ret = afs_fill_super(sb, &params);
ret = afs_fill_super(sb, ctx);
if (ret < 0)
goto error_sb;
as = NULL;
sb->s_flags |= SB_ACTIVE;
} else {
_debug("reuse");
ASSERTCMP(sb->s_flags, &, SB_ACTIVE);
afs_destroy_sbi(as);
as = NULL;
}
afs_put_cell(params.net, params.cell);
key_put(params.key);
fc->root = dget(sb->s_root);
_leave(" = 0 [%p]", sb);
return dget(sb->s_root);
return 0;
error_sb:
deactivate_locked_super(sb);
goto error_key;
error_as:
afs_destroy_sbi(as);
error_key:
key_put(params.key);
error:
afs_put_cell(params.net, params.cell);
_leave(" = %d", ret);
return ERR_PTR(ret);
return ret;
}
static void afs_free_fc(struct fs_context *fc)
{
struct afs_fs_context *ctx = fc->fs_private;
afs_destroy_sbi(fc->s_fs_info);
afs_put_volume(ctx->cell, ctx->volume);
afs_put_cell(ctx->net, ctx->cell);
key_put(ctx->key);
kfree(ctx);
}
static const struct fs_context_operations afs_context_ops = {
.free = afs_free_fc,
.parse_param = afs_parse_param,
.get_tree = afs_get_tree,
};
/*
* Set up the filesystem mount context.
*/
static int afs_init_fs_context(struct fs_context *fc)
{
struct afs_fs_context *ctx;
struct afs_cell *cell;
ctx = kzalloc(sizeof(struct afs_fs_context), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->type = AFSVL_ROVOL;
ctx->net = afs_net(fc->net_ns);
/* Default to the workstation cell. */
rcu_read_lock();
cell = afs_lookup_cell_rcu(ctx->net, NULL, 0);
rcu_read_unlock();
if (IS_ERR(cell))
cell = NULL;
ctx->cell = cell;
fc->fs_private = ctx;
fc->ops = &afs_context_ops;
return 0;
}
/*

4
fs/afs/volume.c
View File

@ -21,7 +21,7 @@ static const char *const afs_voltypes[] = { "R/W", "R/O", "BAK" };
/*
* Allocate a volume record and load it up from a vldb record.
*/
static struct afs_volume *afs_alloc_volume(struct afs_mount_params *params,
static struct afs_volume *afs_alloc_volume(struct afs_fs_context *params,
struct afs_vldb_entry *vldb,
unsigned long type_mask)
{
@ -113,7 +113,7 @@ static struct afs_vldb_entry *afs_vl_lookup_vldb(struct afs_cell *cell,
* - Rule 3: If parent volume is R/W, then only mount R/W volume unless
* explicitly told otherwise
*/
struct afs_volume *afs_create_volume(struct afs_mount_params *params)
struct afs_volume *afs_create_volume(struct afs_fs_context *params)
{
struct afs_vldb_entry *vldb;
struct afs_volume *volume;

4
fs/filesystems.c
View File

@ -16,6 +16,7 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/fs_parser.h>
/*
* Handling of filesystem drivers list.
@ -73,6 +74,9 @@ int register_filesystem(struct file_system_type * fs)
int res = 0;
struct file_system_type ** p;
if (fs->parameters && !fs_validate_description(fs->parameters))
return -EINVAL;
BUG_ON(strchr(fs->name, '.'));
if (fs->next)
return -EBUSY;

642
fs/fs_context.c Normal file
View File

@ -0,0 +1,642 @@
/* Provide a way to create a superblock configuration context within the kernel
* that allows a superblock to be set up prior to mounting.
*
* Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/nsproxy.h>
#include <linux/slab.h>
#include <linux/magic.h>
#include <linux/security.h>
#include <linux/mnt_namespace.h>
#include <linux/pid_namespace.h>
#include <linux/user_namespace.h>
#include <net/net_namespace.h>
#include "mount.h"
#include "internal.h"
enum legacy_fs_param {
LEGACY_FS_UNSET_PARAMS,
LEGACY_FS_MONOLITHIC_PARAMS,
LEGACY_FS_INDIVIDUAL_PARAMS,
};
struct legacy_fs_context {
char *legacy_data; /* Data page for legacy filesystems */
size_t data_size;
enum legacy_fs_param param_type;
};
static int legacy_init_fs_context(struct fs_context *fc);
static const struct constant_table common_set_sb_flag[] = {
{ "dirsync", SB_DIRSYNC },
{ "lazytime", SB_LAZYTIME },
{ "mand", SB_MANDLOCK },
{ "posixacl", SB_POSIXACL },
{ "ro", SB_RDONLY },
{ "sync", SB_SYNCHRONOUS },
};
static const struct constant_table common_clear_sb_flag[] = {
{ "async", SB_SYNCHRONOUS },
{ "nolazytime", SB_LAZYTIME },
{ "nomand", SB_MANDLOCK },
{ "rw", SB_RDONLY },
{ "silent", SB_SILENT },
};
static const char *const forbidden_sb_flag[] = {
"bind",
"dev",
"exec",
"move",
"noatime",
"nodev",
"nodiratime",
"noexec",
"norelatime",
"nostrictatime",
"nosuid",
"private",
"rec",
"relatime",
"remount",
"shared",
"slave",
"strictatime",
"suid",
"unbindable",
};
/*
* Check for a common mount option that manipulates s_flags.
*/
static int vfs_parse_sb_flag(struct fs_context *fc, const char *key)
{
unsigned int token;
unsigned int i;
for (i = 0; i < ARRAY_SIZE(forbidden_sb_flag); i++)
if (strcmp(key, forbidden_sb_flag[i]) == 0)
return -EINVAL;
token = lookup_constant(common_set_sb_flag, key, 0);
if (token) {
fc->sb_flags |= token;
fc->sb_flags_mask |= token;
return 0;
}
token = lookup_constant(common_clear_sb_flag, key, 0);
if (token) {
fc->sb_flags &= ~token;
fc->sb_flags_mask |= token;
return 0;
}
return -ENOPARAM;
}
/**
* vfs_parse_fs_param - Add a single parameter to a superblock config
* @fc: The filesystem context to modify
* @param: The parameter
*
* A single mount option in string form is applied to the filesystem context
* being set up. Certain standard options (for example "ro") are translated
* into flag bits without going to the filesystem. The active security module
* is allowed to observe and poach options. Any other options are passed over
* to the filesystem to parse.
*
* This may be called multiple times for a context.
*
* Returns 0 on success and a negative error code on failure. In the event of
* failure, supplementary error information may have been set.
*/
int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param)
{
int ret;
if (!param->key)
return invalf(fc, "Unnamed parameter\n");
ret = vfs_parse_sb_flag(fc, param->key);
if (ret != -ENOPARAM)
return ret;
ret = security_fs_context_parse_param(fc, param);
if (ret != -ENOPARAM)
/* Param belongs to the LSM or is disallowed by the LSM; so
* don't pass to the FS.
*/
return ret;
if (fc->ops->parse_param) {
ret = fc->ops->parse_param(fc, param);
if (ret != -ENOPARAM)
return ret;
}
/* If the filesystem doesn't take any arguments, give it the
* default handling of source.
*/
if (strcmp(param->key, "source") == 0) {
if (param->type != fs_value_is_string)
return invalf(fc, "VFS: Non-string source");
if (fc->source)
return invalf(fc, "VFS: Multiple sources");
fc->source = param->string;
param->string = NULL;
return 0;
}
return invalf(fc, "%s: Unknown parameter '%s'",
fc->fs_type->name, param->key);
}
EXPORT_SYMBOL(vfs_parse_fs_param);
/**
* vfs_parse_fs_string - Convenience function to just parse a string.
*/
int vfs_parse_fs_string(struct fs_context *fc, const char *key,
const char *value, size_t v_size)
{
int ret;
struct fs_parameter param = {
.key = key,
.type = fs_value_is_string,
.size = v_size,
};
if (v_size > 0) {
param.string = kmemdup_nul(value, v_size, GFP_KERNEL);
if (!param.string)
return -ENOMEM;
}
ret = vfs_parse_fs_param(fc, &param);
kfree(param.string);
return ret;
}
EXPORT_SYMBOL(vfs_parse_fs_string);
/**
* generic_parse_monolithic - Parse key[=val][,key[=val]]* mount data
* @ctx: The superblock configuration to fill in.
* @data: The data to parse
*
* Parse a blob of data that's in key[=val][,key[=val]]* form. This can be
* called from the ->monolithic_mount_data() fs_context operation.
*
* Returns 0 on success or the error returned by the ->parse_option() fs_context
* operation on failure.
*/
int generic_parse_monolithic(struct fs_context *fc, void *data)
{
char *options = data, *key;
int ret = 0;
if (!options)
return 0;
ret = security_sb_eat_lsm_opts(options, &fc->security);
if (ret)
return ret;
while ((key = strsep(&options, ",")) != NULL) {
if (*key) {
size_t v_len = 0;
char *value = strchr(key, '=');
if (value) {
if (value == key)
continue;
*value++ = 0;
v_len = strlen(value);
}
ret = vfs_parse_fs_string(fc, key, value, v_len);
if (ret < 0)
break;
}
}
return ret;
}
EXPORT_SYMBOL(generic_parse_monolithic);
/**
* alloc_fs_context - Create a filesystem context.
* @fs_type: The filesystem type.
* @reference: The dentry from which this one derives (or NULL)
* @sb_flags: Filesystem/superblock flags (SB_*)
* @sb_flags_mask: Applicable members of @sb_flags
* @purpose: The purpose that this configuration shall be used for.
*
* Open a filesystem and create a mount context. The mount context is
* initialised with the supplied flags and, if a submount/automount from
* another superblock (referred to by @reference) is supplied, may have
* parameters such as namespaces copied across from that superblock.
*/
static struct fs_context *alloc_fs_context(struct file_system_type *fs_type,
struct dentry *reference,
unsigned int sb_flags,
unsigned int sb_flags_mask,
enum fs_context_purpose purpose)
{
int (*init_fs_context)(struct fs_context *);
struct fs_context *fc;
int ret = -ENOMEM;
fc = kzalloc(sizeof(struct fs_context), GFP_KERNEL);
if (!fc)
return ERR_PTR(-ENOMEM);
fc->purpose = purpose;
fc->sb_flags = sb_flags;
fc->sb_flags_mask = sb_flags_mask;
fc->fs_type = get_filesystem(fs_type);
fc->cred = get_current_cred();
fc->net_ns = get_net(current->nsproxy->net_ns);
switch (purpose) {
case FS_CONTEXT_FOR_MOUNT:
fc->user_ns = get_user_ns(fc->cred->user_ns);
break;
case FS_CONTEXT_FOR_SUBMOUNT:
fc->user_ns = get_user_ns(reference->d_sb->s_user_ns);
break;
case FS_CONTEXT_FOR_RECONFIGURE:
/* We don't pin any namespaces as the superblock's
* subscriptions cannot be changed at this point.
*/
atomic_inc(&reference->d_sb->s_active);
fc->root = dget(reference);
break;
}
/* TODO: Make all filesystems support this unconditionally */
init_fs_context = fc->fs_type->init_fs_context;
if (!init_fs_context)
init_fs_context = legacy_init_fs_context;
ret = init_fs_context(fc);
if (ret < 0)
goto err_fc;
fc->need_free = true;
return fc;
err_fc:
put_fs_context(fc);
return ERR_PTR(ret);
}
struct fs_context *fs_context_for_mount(struct file_system_type *fs_type,
unsigned int sb_flags)
{
return alloc_fs_context(fs_type, NULL, sb_flags, 0,
FS_CONTEXT_FOR_MOUNT);
}
EXPORT_SYMBOL(fs_context_for_mount);
struct fs_context *fs_context_for_reconfigure(struct dentry *dentry,
unsigned int sb_flags,
unsigned int sb_flags_mask)
{
return alloc_fs_context(dentry->d_sb->s_type, dentry, sb_flags,
sb_flags_mask, FS_CONTEXT_FOR_RECONFIGURE);
}
EXPORT_SYMBOL(fs_context_for_reconfigure);
struct fs_context *fs_context_for_submount(struct file_system_type *type,
struct dentry *reference)
{
return alloc_fs_context(type, reference, 0, 0, FS_CONTEXT_FOR_SUBMOUNT);
}
EXPORT_SYMBOL(fs_context_for_submount);
void fc_drop_locked(struct fs_context *fc)
{
struct super_block *sb = fc->root->d_sb;
dput(fc->root);
fc->root = NULL;
deactivate_locked_super(sb);
}
static void legacy_fs_context_free(struct fs_context *fc);
/**
* vfs_dup_fc_config: Duplicate a filesystem context.
* @src_fc: The context to copy.
*/
struct fs_context *vfs_dup_fs_context(struct fs_context *src_fc)
{
struct fs_context *fc;
int ret;
if (!src_fc->ops->dup)
return ERR_PTR(-EOPNOTSUPP);
fc = kmemdup(src_fc, sizeof(struct fs_context), GFP_KERNEL);
if (!fc)
return ERR_PTR(-ENOMEM);
fc->fs_private = NULL;
fc->s_fs_info = NULL;
fc->source = NULL;
fc->security = NULL;
get_filesystem(fc->fs_type);
get_net(fc->net_ns);
get_user_ns(fc->user_ns);
get_cred(fc->cred);
/* Can't call put until we've called ->dup */
ret = fc->ops->dup(fc, src_fc);
if (ret < 0)
goto err_fc;
ret = security_fs_context_dup(fc, src_fc);
if (ret < 0)
goto err_fc;
return fc;
err_fc:
put_fs_context(fc);
return ERR_PTR(ret);
}
EXPORT_SYMBOL(vfs_dup_fs_context);
#ifdef CONFIG_PRINTK
/**
* logfc - Log a message to a filesystem context
* @fc: The filesystem context to log to.
* @fmt: The format of the buffer.
*/
void logfc(struct fs_context *fc, const char *fmt, ...)
{
va_list va;
va_start(va, fmt);
switch (fmt[0]) {
case 'w':
vprintk_emit(0, LOGLEVEL_WARNING, NULL, 0, fmt, va);
break;
case 'e':
vprintk_emit(0, LOGLEVEL_ERR, NULL, 0, fmt, va);
break;
default:
vprintk_emit(0, LOGLEVEL_NOTICE, NULL, 0, fmt, va);
break;
}
pr_cont("\n");
va_end(va);
}
EXPORT_SYMBOL(logfc);
#endif
/**
* put_fs_context - Dispose of a superblock configuration context.
* @fc: The context to dispose of.
*/
void put_fs_context(struct fs_context *fc)
{
struct super_block *sb;
if (fc->root) {
sb = fc->root->d_sb;
dput(fc->root);
fc->root = NULL;
deactivate_super(sb);
}
if (fc->need_free && fc->ops && fc->ops->free)
fc->ops->free(fc);
security_free_mnt_opts(&fc->security);
put_net(fc->net_ns);
put_user_ns(fc->user_ns);
put_cred(fc->cred);
kfree(fc->subtype);
put_filesystem(fc->fs_type);
kfree(fc->source);
kfree(fc);
}
EXPORT_SYMBOL(put_fs_context);
/*
* Free the config for a filesystem that doesn't support fs_context.
*/
static void legacy_fs_context_free(struct fs_context *fc)
{
struct legacy_fs_context *ctx = fc->fs_private;
if (ctx) {
if (ctx->param_type == LEGACY_FS_INDIVIDUAL_PARAMS)
kfree(ctx->legacy_data);
kfree(ctx);
}
}
/*
* Duplicate a legacy config.
*/
static int legacy_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc)
{
struct legacy_fs_context *ctx;
struct legacy_fs_context *src_ctx = src_fc->fs_private;
ctx = kmemdup(src_ctx, sizeof(*src_ctx), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
if (ctx->param_type == LEGACY_FS_INDIVIDUAL_PARAMS) {
ctx->legacy_data = kmemdup(src_ctx->legacy_data,
src_ctx->data_size, GFP_KERNEL);
if (!ctx->legacy_data) {
kfree(ctx);
return -ENOMEM;
}
}
fc->fs_private = ctx;
return 0;
}
/*
* Add a parameter to a legacy config. We build up a comma-separated list of
* options.
*/
static int legacy_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
struct legacy_fs_context *ctx = fc->fs_private;
unsigned int size = ctx->data_size;
size_t len = 0;
if (strcmp(param->key, "source") == 0) {
if (param->type != fs_value_is_string)
return invalf(fc, "VFS: Legacy: Non-string source");
if (fc->source)
return invalf(fc, "VFS: Legacy: Multiple sources");
fc->source = param->string;
param->string = NULL;
return 0;
}
if ((fc->fs_type->fs_flags & FS_HAS_SUBTYPE) &&
strcmp(param->key, "subtype") == 0) {
if (param->type != fs_value_is_string)
return invalf(fc, "VFS: Legacy: Non-string subtype");
if (fc->subtype)
return invalf(fc, "VFS: Legacy: Multiple subtype");
fc->subtype = param->string;
param->string = NULL;
return 0;
}
if (ctx->param_type == LEGACY_FS_MONOLITHIC_PARAMS)
return invalf(fc, "VFS: Legacy: Can't mix monolithic and individual options");
switch (param->type) {
case fs_value_is_string:
len = 1 + param->size;
/* Fall through */
case fs_value_is_flag:
len += strlen(param->key);
break;
default:
return invalf(fc, "VFS: Legacy: Parameter type for '%s' not supported",
param->key);
}
if (len > PAGE_SIZE - 2 - size)
return invalf(fc, "VFS: Legacy: Cumulative options too large");
if (strchr(param->key, ',') ||
(param->type == fs_value_is_string &&
memchr(param->string, ',', param->size)))
return invalf(fc, "VFS: Legacy: Option '%s' contained comma",
param->key);
if (!ctx->legacy_data) {
ctx->legacy_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!ctx->legacy_data)
return -ENOMEM;
}
ctx->legacy_data[size++] = ',';
len = strlen(param->key);
memcpy(ctx->legacy_data + size, param->key, len);
size += len;
if (param->type == fs_value_is_string) {
ctx->legacy_data[size++] = '=';
memcpy(ctx->legacy_data + size, param->string, param->size);
size += param->size;
}
ctx->legacy_data[size] = '\0';
ctx->data_size = size;
ctx->param_type = LEGACY_FS_INDIVIDUAL_PARAMS;
return 0;
}
/*
* Add monolithic mount data.
*/
static int legacy_parse_monolithic(struct fs_context *fc, void *data)
{
struct legacy_fs_context *ctx = fc->fs_private;
if (ctx->param_type != LEGACY_FS_UNSET_PARAMS) {
pr_warn("VFS: Can't mix monolithic and individual options\n");
return -EINVAL;
}
ctx->legacy_data = data;
ctx->param_type = LEGACY_FS_MONOLITHIC_PARAMS;
if (!ctx->legacy_data)
return 0;
if (fc->fs_type->fs_flags & FS_BINARY_MOUNTDATA)
return 0;
return security_sb_eat_lsm_opts(ctx->legacy_data, &fc->security);
}
/*
* Get a mountable root with the legacy mount command.
*/
static int legacy_get_tree(struct fs_context *fc)
{
struct legacy_fs_context *ctx = fc->fs_private;
struct super_block *sb;
struct dentry *root;
root = fc->fs_type->mount(fc->fs_type, fc->sb_flags,
fc->source, ctx->legacy_data);
if (IS_ERR(root))
return PTR_ERR(root);
sb = root->d_sb;
BUG_ON(!sb);
fc->root = root;
return 0;
}
/*
* Handle remount.
*/
static int legacy_reconfigure(struct fs_context *fc)
{
struct legacy_fs_context *ctx = fc->fs_private;
struct super_block *sb = fc->root->d_sb;
if (!sb->s_op->remount_fs)
return 0;
return sb->s_op->remount_fs(sb, &fc->sb_flags,
ctx ? ctx->legacy_data : NULL);
}
const struct fs_context_operations legacy_fs_context_ops = {
.free = legacy_fs_context_free,
.dup = legacy_fs_context_dup,
.parse_param = legacy_parse_param,
.parse_monolithic = legacy_parse_monolithic,
.get_tree = legacy_get_tree,
.reconfigure = legacy_reconfigure,
};
/*
* Initialise a legacy context for a filesystem that doesn't support
* fs_context.
*/
static int legacy_init_fs_context(struct fs_context *fc)
{
fc->fs_private = kzalloc(sizeof(struct legacy_fs_context), GFP_KERNEL);
if (!fc->fs_private)
return -ENOMEM;
fc->ops = &legacy_fs_context_ops;
return 0;
}
int parse_monolithic_mount_data(struct fs_context *fc, void *data)
{
int (*monolithic_mount_data)(struct fs_context *, void *);
monolithic_mount_data = fc->ops->parse_monolithic;
if (!monolithic_mount_data)
monolithic_mount_data = generic_parse_monolithic;
return monolithic_mount_data(fc, data);
}

447
fs/fs_parser.c Normal file
View File

@ -0,0 +1,447 @@
/* Filesystem parameter parser.
*
* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/export.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/slab.h>
#include <linux/security.h>
#include <linux/namei.h>
#include "internal.h"
static const struct constant_table bool_names[] = {
{ "0", false },
{ "1", true },
{ "false", false },
{ "no", false },
{ "true", true },
{ "yes", true },
};
/**
* lookup_constant - Look up a constant by name in an ordered table
* @tbl: The table of constants to search.
* @tbl_size: The size of the table.
* @name: The name to look up.
* @not_found: The value to return if the name is not found.
*/
int __lookup_constant(const struct constant_table *tbl, size_t tbl_size,
const char *name, int not_found)
{
unsigned int i;
for (i = 0; i < tbl_size; i++)
if (strcmp(name, tbl[i].name) == 0)
return tbl[i].value;
return not_found;
}
EXPORT_SYMBOL(__lookup_constant);
static const struct fs_parameter_spec *fs_lookup_key(
const struct fs_parameter_description *desc,
const char *name)
{
const struct fs_parameter_spec *p;
if (!desc->specs)
return NULL;
for (p = desc->specs; p->name; p++)
if (strcmp(p->name, name) == 0)
return p;
return NULL;
}
/*
* fs_parse - Parse a filesystem configuration parameter
* @fc: The filesystem context to log errors through.
* @desc: The parameter description to use.
* @param: The parameter.
* @result: Where to place the result of the parse
*
* Parse a filesystem configuration parameter and attempt a conversion for a
* simple parameter for which this is requested. If successful, the determined
* parameter ID is placed into @result->key, the desired type is indicated in
* @result->t and any converted value is placed into an appropriate member of
* the union in @result.
*
* The function returns the parameter number if the parameter was matched,
* -ENOPARAM if it wasn't matched and @desc->ignore_unknown indicated that
* unknown parameters are okay and -EINVAL if there was a conversion issue or
* the parameter wasn't recognised and unknowns aren't okay.
*/
int fs_parse(struct fs_context *fc,
const struct fs_parameter_description *desc,
struct fs_parameter *param,
struct fs_parse_result *result)
{
const struct fs_parameter_spec *p;
const struct fs_parameter_enum *e;
int ret = -ENOPARAM, b;
result->has_value = !!param->string;
result->negated = false;
result->uint_64 = 0;
p = fs_lookup_key(desc, param->key);
if (!p) {
/* If we didn't find something that looks like "noxxx", see if
* "xxx" takes the "no"-form negative - but only if there
* wasn't an value.
*/
if (result->has_value)
goto unknown_parameter;
if (param->key[0] != 'n' || param->key[1] != 'o' || !param->key[2])
goto unknown_parameter;
p = fs_lookup_key(desc, param->key + 2);
if (!p)
goto unknown_parameter;
if (!(p->flags & fs_param_neg_with_no))
goto unknown_parameter;
result->boolean = false;
result->negated = true;
}
if (p->flags & fs_param_deprecated)
warnf(fc, "%s: Deprecated parameter '%s'",
desc->name, param->key);
if (result->negated)
goto okay;
/* Certain parameter types only take a string and convert it. */
switch (p->type) {
case __fs_param_wasnt_defined:
return -EINVAL;
case fs_param_is_u32:
case fs_param_is_u32_octal:
case fs_param_is_u32_hex:
case fs_param_is_s32:
case fs_param_is_u64:
case fs_param_is_enum:
case fs_param_is_string:
if (param->type != fs_value_is_string)
goto bad_value;
if (!result->has_value) {
if (p->flags & fs_param_v_optional)
goto okay;
goto bad_value;
}
/* Fall through */
default:
break;
}
/* Try to turn the type we were given into the type desired by the
* parameter and give an error if we can't.
*/
switch (p->type) {
case fs_param_is_flag:
if (param->type != fs_value_is_flag &&
(param->type != fs_value_is_string || result->has_value))
return invalf(fc, "%s: Unexpected value for '%s'",
desc->name, param->key);
result->boolean = true;
goto okay;
case fs_param_is_bool:
switch (param->type) {
case fs_value_is_flag:
result->boolean = true;
goto okay;
case fs_value_is_string:
if (param->size == 0) {
result->boolean = true;
goto okay;
}
b = lookup_constant(bool_names, param->string, -1);
if (b == -1)
goto bad_value;
result->boolean = b;
goto okay;
default:
goto bad_value;
}
case fs_param_is_u32:
ret = kstrtouint(param->string, 0, &result->uint_32);
goto maybe_okay;
case fs_param_is_u32_octal:
ret = kstrtouint(param->string, 8, &result->uint_32);
goto maybe_okay;
case fs_param_is_u32_hex:
ret = kstrtouint(param->string, 16, &result->uint_32);
goto maybe_okay;
case fs_param_is_s32:
ret = kstrtoint(param->string, 0, &result->int_32);
goto maybe_okay;
case fs_param_is_u64:
ret = kstrtoull(param->string, 0, &result->uint_64);
goto maybe_okay;
case fs_param_is_enum:
for (e = desc->enums; e->name[0]; e++) {
if (e->opt == p->opt &&
strcmp(e->name, param->string) == 0) {
result->uint_32 = e->value;
goto okay;
}
}
goto bad_value;
case fs_param_is_string:
goto okay;
case fs_param_is_blob:
if (param->type != fs_value_is_blob)
goto bad_value;
goto okay;
case fs_param_is_fd: {
if (param->type != fs_value_is_file)
goto bad_value;
goto okay;
}
case fs_param_is_blockdev:
case fs_param_is_path:
goto okay;
default:
BUG();
}
maybe_okay:
if (ret < 0)
goto bad_value;
okay:
return p->opt;
bad_value:
return invalf(fc, "%s: Bad value for '%s'", desc->name, param->key);
unknown_parameter:
return -ENOPARAM;
}
EXPORT_SYMBOL(fs_parse);
/**
* fs_lookup_param - Look up a path referred to by a parameter
* @fc: The filesystem context to log errors through.
* @param: The parameter.
* @want_bdev: T if want a blockdev
* @_path: The result of the lookup
*/
int fs_lookup_param(struct fs_context *fc,
struct fs_parameter *param,
bool want_bdev,
struct path *_path)
{
struct filename *f;
unsigned int flags = 0;
bool put_f;
int ret;
switch (param->type) {
case fs_value_is_string:
f = getname_kernel(param->string);
if (IS_ERR(f))
return PTR_ERR(f);
put_f = true;
break;
case fs_value_is_filename_empty:
flags = LOOKUP_EMPTY;
/* Fall through */
case fs_value_is_filename:
f = param->name;
put_f = false;
break;
default:
return invalf(fc, "%s: not usable as path", param->key);
}
ret = filename_lookup(param->dirfd, f, flags, _path, NULL);
if (ret < 0) {
errorf(fc, "%s: Lookup failure for '%s'", param->key, f->name);
goto out;
}
if (want_bdev &&
!S_ISBLK(d_backing_inode(_path->dentry)->i_mode)) {
path_put(_path);
_path->dentry = NULL;
_path->mnt = NULL;
errorf(fc, "%s: Non-blockdev passed as '%s'",
param->key, f->name);
ret = -ENOTBLK;
}
out:
if (put_f)
putname(f);
return ret;
}
EXPORT_SYMBOL(fs_lookup_param);
#ifdef CONFIG_VALIDATE_FS_PARSER
/**
* validate_constant_table - Validate a constant table
* @name: Name to use in reporting
* @tbl: The constant table to validate.
* @tbl_size: The size of the table.
* @low: The lowest permissible value.
* @high: The highest permissible value.
* @special: One special permissible value outside of the range.
*/
bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
int low, int high, int special)
{
size_t i;
bool good = true;
if (tbl_size == 0) {
pr_warn("VALIDATE C-TBL: Empty\n");
return true;
}
for (i = 0; i < tbl_size; i++) {
if (!tbl[i].name) {
pr_err("VALIDATE C-TBL[%zu]: Null\n", i);
good = false;
} else if (i > 0 && tbl[i - 1].name) {
int c = strcmp(tbl[i-1].name, tbl[i].name);
if (c == 0) {
pr_err("VALIDATE C-TBL[%zu]: Duplicate %s\n",
i, tbl[i].name);
good = false;
}
if (c > 0) {
pr_err("VALIDATE C-TBL[%zu]: Missorted %s>=%s\n",
i, tbl[i-1].name, tbl[i].name);
good = false;
}
}
if (tbl[i].value != special &&
(tbl[i].value < low || tbl[i].value > high)) {
pr_err("VALIDATE C-TBL[%zu]: %s->%d const out of range (%d-%d)\n",
i, tbl[i].name, tbl[i].value, low, high);
good = false;
}
}
return good;
}
/**
* fs_validate_description - Validate a parameter description
* @desc: The parameter description to validate.
*/
bool fs_validate_description(const struct fs_parameter_description *desc)
{
const struct fs_parameter_spec *param, *p2;
const struct fs_parameter_enum *e;
const char *name = desc->name;
unsigned int nr_params = 0;
bool good = true, enums = false;
pr_notice("*** VALIDATE %s ***\n", name);
if (!name[0]) {
pr_err("VALIDATE Parser: No name\n");
name = "Unknown";
good = false;
}
if (desc->specs) {
for (param = desc->specs; param->name; param++) {
enum fs_parameter_type t = param->type;
/* Check that the type is in range */
if (t == __fs_param_wasnt_defined ||
t >= nr__fs_parameter_type) {
pr_err("VALIDATE %s: PARAM[%s] Bad type %u\n",
name, param->name, t);
good = false;
} else if (t == fs_param_is_enum) {
enums = true;
}
/* Check for duplicate parameter names */
for (p2 = desc->specs; p2 < param; p2++) {
if (strcmp(param->name, p2->name) == 0) {
pr_err("VALIDATE %s: PARAM[%s]: Duplicate\n",
name, param->name);
good = false;
}
}
}
nr_params = param - desc->specs;
}
if (desc->enums) {
if (!nr_params) {
pr_err("VALIDATE %s: Enum table but no parameters\n",
name);
good = false;
goto no_enums;
}
if (!enums) {
pr_err("VALIDATE %s: Enum table but no enum-type values\n",
name);
good = false;
goto no_enums;
}
for (e = desc->enums; e->name[0]; e++) {
/* Check that all entries in the enum table have at
* least one parameter that uses them.
*/
for (param = desc->specs; param->name; param++) {
if (param->opt == e->opt &&
param->type != fs_param_is_enum) {
pr_err("VALIDATE %s: e[%lu] enum val for %s\n",
name, e - desc->enums, param->name);
good = false;
}
}
}
/* Check that all enum-type parameters have at least one enum
* value in the enum table.
*/
for (param = desc->specs; param->name; param++) {
if (param->type != fs_param_is_enum)
continue;
for (e = desc->enums; e->name[0]; e++)
if (e->opt == param->opt)
break;
if (!e->name[0]) {
pr_err("VALIDATE %s: PARAM[%s] enum with no values\n",
name, param->name);
good = false;
}
}
} else {
if (enums) {
pr_err("VALIDATE %s: enum-type values, but no enum table\n",
name);
good = false;
goto no_enums;
}
}
no_enums:
return good;
}
#endif /* CONFIG_VALIDATE_FS_PARSER */

360
fs/hugetlbfs/inode.c
View File

@ -27,7 +27,7 @@
#include <linux/backing-dev.h>
#include <linux/hugetlb.h>
#include <linux/pagevec.h>
#include <linux/parser.h>
#include <linux/fs_parser.h>
#include <linux/mman.h>
#include <linux/slab.h>
#include <linux/dnotify.h>
@ -45,11 +45,17 @@ const struct file_operations hugetlbfs_file_operations;
static const struct inode_operations hugetlbfs_dir_inode_operations;
static const struct inode_operations hugetlbfs_inode_operations;
struct hugetlbfs_config {
enum hugetlbfs_size_type { NO_SIZE, SIZE_STD, SIZE_PERCENT };
struct hugetlbfs_fs_context {
struct hstate *hstate;
unsigned long long max_size_opt;
unsigned long long min_size_opt;
long max_hpages;
long nr_inodes;
long min_hpages;
enum hugetlbfs_size_type max_val_type;
enum hugetlbfs_size_type min_val_type;
kuid_t uid;
kgid_t gid;
umode_t mode;
@ -57,22 +63,30 @@ struct hugetlbfs_config {
int sysctl_hugetlb_shm_group;
enum {
Opt_size, Opt_nr_inodes,
Opt_mode, Opt_uid, Opt_gid,
Opt_pagesize, Opt_min_size,
Opt_err,
enum hugetlb_param {
Opt_gid,
Opt_min_size,
Opt_mode,
Opt_nr_inodes,
Opt_pagesize,
Opt_size,
Opt_uid,
};
static const match_table_t tokens = {
{Opt_size, "size=%s"},
{Opt_nr_inodes, "nr_inodes=%s"},
{Opt_mode, "mode=%o"},
{Opt_uid, "uid=%u"},
{Opt_gid, "gid=%u"},
{Opt_pagesize, "pagesize=%s"},
{Opt_min_size, "min_size=%s"},
{Opt_err, NULL},
static const struct fs_parameter_spec hugetlb_param_specs[] = {
fsparam_u32 ("gid", Opt_gid),
fsparam_string("min_size", Opt_min_size),
fsparam_u32 ("mode", Opt_mode),
fsparam_string("nr_inodes", Opt_nr_inodes),
fsparam_string("pagesize", Opt_pagesize),
fsparam_string("size", Opt_size),
fsparam_u32 ("uid", Opt_uid),
{}
};
static const struct fs_parameter_description hugetlb_fs_parameters = {
.name = "hugetlbfs",
.specs = hugetlb_param_specs,
};
#ifdef CONFIG_NUMA
@ -708,16 +722,16 @@ static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
}
static struct inode *hugetlbfs_get_root(struct super_block *sb,
struct hugetlbfs_config *config)
struct hugetlbfs_fs_context *ctx)
{
struct inode *inode;
inode = new_inode(sb);
if (inode) {
inode->i_ino = get_next_ino();
inode->i_mode = S_IFDIR | config->mode;
inode->i_uid = config->uid;
inode->i_gid = config->gid;
inode->i_mode = S_IFDIR | ctx->mode;
inode->i_uid = ctx->uid;
inode->i_gid = ctx->gid;
inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
inode->i_op = &hugetlbfs_dir_inode_operations;
inode->i_fop = &simple_dir_operations;
@ -1093,8 +1107,6 @@ static const struct super_operations hugetlbfs_ops = {
.show_options = hugetlbfs_show_options,
};
enum hugetlbfs_size_type { NO_SIZE, SIZE_STD, SIZE_PERCENT };
/*
* Convert size option passed from command line to number of huge pages
* in the pool specified by hstate. Size option could be in bytes
@ -1117,170 +1129,151 @@ hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
return size_opt;
}
static int
hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
/*
* Parse one mount parameter.
*/
static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
char *p, *rest;
substring_t args[MAX_OPT_ARGS];
int option;
unsigned long long max_size_opt = 0, min_size_opt = 0;
enum hugetlbfs_size_type max_val_type = NO_SIZE, min_val_type = NO_SIZE;
struct hugetlbfs_fs_context *ctx = fc->fs_private;
struct fs_parse_result result;
char *rest;
unsigned long ps;
int opt;
if (!options)
opt = fs_parse(fc, &hugetlb_fs_parameters, param, &result);
if (opt < 0)
return opt;
switch (opt) {
case Opt_uid:
ctx->uid = make_kuid(current_user_ns(), result.uint_32);
if (!uid_valid(ctx->uid))
goto bad_val;
return 0;
while ((p = strsep(&options, ",")) != NULL) {
int token;
if (!*p)
continue;
case Opt_gid:
ctx->gid = make_kgid(current_user_ns(), result.uint_32);
if (!gid_valid(ctx->gid))
goto bad_val;
return 0;
token = match_token(p, tokens, args);
switch (token) {
case Opt_uid:
if (match_int(&args[0], &option))
goto bad_val;
pconfig->uid = make_kuid(current_user_ns(), option);
if (!uid_valid(pconfig->uid))
goto bad_val;
break;
case Opt_mode:
ctx->mode = result.uint_32 & 01777U;
return 0;
case Opt_gid:
if (match_int(&args[0], &option))
goto bad_val;
pconfig->gid = make_kgid(current_user_ns(), option);
if (!gid_valid(pconfig->gid))
goto bad_val;
break;
case Opt_size:
/* memparse() will accept a K/M/G without a digit */
if (!isdigit(param->string[0]))
goto bad_val;
ctx->max_size_opt = memparse(param->string, &rest);
ctx->max_val_type = SIZE_STD;
if (*rest == '%')
ctx->max_val_type = SIZE_PERCENT;
return 0;
case Opt_mode:
if (match_octal(&args[0], &option))
goto bad_val;
pconfig->mode = option & 01777U;
break;
case Opt_nr_inodes:
/* memparse() will accept a K/M/G without a digit */
if (!isdigit(param->string[0]))
goto bad_val;
ctx->nr_inodes = memparse(param->string, &rest);
return 0;
case Opt_size: {
/* memparse() will accept a K/M/G without a digit */
if (!isdigit(*args[0].from))
goto bad_val;
max_size_opt = memparse(args[0].from, &rest);
max_val_type = SIZE_STD;
if (*rest == '%')
max_val_type = SIZE_PERCENT;
break;
}
case Opt_nr_inodes:
/* memparse() will accept a K/M/G without a digit */
if (!isdigit(*args[0].from))
goto bad_val;
pconfig->nr_inodes = memparse(args[0].from, &rest);
break;
case Opt_pagesize: {
unsigned long ps;
ps = memparse(args[0].from, &rest);
pconfig->hstate = size_to_hstate(ps);
if (!pconfig->hstate) {
pr_err("Unsupported page size %lu MB\n",
ps >> 20);
return -EINVAL;
}
break;
}
case Opt_min_size: {
/* memparse() will accept a K/M/G without a digit */
if (!isdigit(*args[0].from))
goto bad_val;
min_size_opt = memparse(args[0].from, &rest);
min_val_type = SIZE_STD;
if (*rest == '%')
min_val_type = SIZE_PERCENT;
break;
}
default:
pr_err("Bad mount option: \"%s\"\n", p);
case Opt_pagesize:
ps = memparse(param->string, &rest);
ctx->hstate = size_to_hstate(ps);
if (!ctx->hstate) {
pr_err("Unsupported page size %lu MB\n", ps >> 20);
return -EINVAL;
break;
}
return 0;
case Opt_min_size:
/* memparse() will accept a K/M/G without a digit */
if (!isdigit(param->string[0]))
goto bad_val;
ctx->min_size_opt = memparse(param->string, &rest);
ctx->min_val_type = SIZE_STD;
if (*rest == '%')
ctx->min_val_type = SIZE_PERCENT;
return 0;
default:
return -EINVAL;
}
bad_val:
return invalf(fc, "hugetlbfs: Bad value '%s' for mount option '%s'\n",
param->string, param->key);
}
/*
* Validate the parsed options.
*/
static int hugetlbfs_validate(struct fs_context *fc)
{
struct hugetlbfs_fs_context *ctx = fc->fs_private;
/*
* Use huge page pool size (in hstate) to convert the size
* options to number of huge pages. If NO_SIZE, -1 is returned.
*/
pconfig->max_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
max_size_opt, max_val_type);
pconfig->min_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
min_size_opt, min_val_type);
ctx->max_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
ctx->max_size_opt,
ctx->max_val_type);
ctx->min_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
ctx->min_size_opt,
ctx->min_val_type);
/*
* If max_size was specified, then min_size must be smaller
*/
if (max_val_type > NO_SIZE &&
pconfig->min_hpages > pconfig->max_hpages) {
pr_err("minimum size can not be greater than maximum size\n");
if (ctx->max_val_type > NO_SIZE &&
ctx->min_hpages > ctx->max_hpages) {
pr_err("Minimum size can not be greater than maximum size\n");
return -EINVAL;
}
return 0;
bad_val:
pr_err("Bad value '%s' for mount option '%s'\n", args[0].from, p);
return -EINVAL;
}
static int
hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc)
{
int ret;
struct hugetlbfs_config config;
struct hugetlbfs_fs_context *ctx = fc->fs_private;
struct hugetlbfs_sb_info *sbinfo;
config.max_hpages = -1; /* No limit on size by default */
config.nr_inodes = -1; /* No limit on number of inodes by default */
config.uid = current_fsuid();
config.gid = current_fsgid();
config.mode = 0755;
config.hstate = &default_hstate;
config.min_hpages = -1; /* No default minimum size */
ret = hugetlbfs_parse_options(data, &config);
if (ret)
return ret;
sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
if (!sbinfo)
return -ENOMEM;
sb->s_fs_info = sbinfo;
sbinfo->hstate = config.hstate;
spin_lock_init(&sbinfo->stat_lock);
sbinfo->max_inodes = config.nr_inodes;
sbinfo->free_inodes = config.nr_inodes;
sbinfo->spool = NULL;
sbinfo->uid = config.uid;
sbinfo->gid = config.gid;
sbinfo->mode = config.mode;
sbinfo->hstate = ctx->hstate;
sbinfo->max_inodes = ctx->nr_inodes;
sbinfo->free_inodes = ctx->nr_inodes;
sbinfo->spool = NULL;
sbinfo->uid = ctx->uid;
sbinfo->gid = ctx->gid;
sbinfo->mode = ctx->mode;
/*
* Allocate and initialize subpool if maximum or minimum size is
* specified. Any needed reservations (for minimim size) are taken
* taken when the subpool is created.
*/
if (config.max_hpages != -1 || config.min_hpages != -1) {
sbinfo->spool = hugepage_new_subpool(config.hstate,
config.max_hpages,
config.min_hpages);
if (ctx->max_hpages != -1 || ctx->min_hpages != -1) {
sbinfo->spool = hugepage_new_subpool(ctx->hstate,
ctx->max_hpages,
ctx->min_hpages);
if (!sbinfo->spool)
goto out_free;
}
sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_blocksize = huge_page_size(config.hstate);
sb->s_blocksize_bits = huge_page_shift(config.hstate);
sb->s_blocksize = huge_page_size(ctx->hstate);
sb->s_blocksize_bits = huge_page_shift(ctx->hstate);
sb->s_magic = HUGETLBFS_MAGIC;
sb->s_op = &hugetlbfs_ops;
sb->s_time_gran = 1;
sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx));
if (!sb->s_root)
goto out_free;
return 0;
@ -1290,16 +1283,52 @@ hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
return -ENOMEM;
}
static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
static int hugetlbfs_get_tree(struct fs_context *fc)
{
return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
int err = hugetlbfs_validate(fc);
if (err)
return err;
return vfs_get_super(fc, vfs_get_independent_super, hugetlbfs_fill_super);
}
static void hugetlbfs_fs_context_free(struct fs_context *fc)
{
kfree(fc->fs_private);
}
static const struct fs_context_operations hugetlbfs_fs_context_ops = {
.free = hugetlbfs_fs_context_free,
.parse_param = hugetlbfs_parse_param,
.get_tree = hugetlbfs_get_tree,
};
static int hugetlbfs_init_fs_context(struct fs_context *fc)
{
struct hugetlbfs_fs_context *ctx;
ctx = kzalloc(sizeof(struct hugetlbfs_fs_context), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->max_hpages = -1; /* No limit on size by default */
ctx->nr_inodes = -1; /* No limit on number of inodes by default */
ctx->uid = current_fsuid();
ctx->gid = current_fsgid();
ctx->mode = 0755;
ctx->hstate = &default_hstate;
ctx->min_hpages = -1; /* No default minimum size */
ctx->max_val_type = NO_SIZE;
ctx->min_val_type = NO_SIZE;
fc->fs_private = ctx;
fc->ops = &hugetlbfs_fs_context_ops;
return 0;
}
static struct file_system_type hugetlbfs_fs_type = {
.name = "hugetlbfs",
.mount = hugetlbfs_mount,
.kill_sb = kill_litter_super,
.name = "hugetlbfs",
.init_fs_context = hugetlbfs_init_fs_context,
.parameters = &hugetlb_fs_parameters,
.kill_sb = kill_litter_super,
};
static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
@ -1384,8 +1413,29 @@ struct file *hugetlb_file_setup(const char *name, size_t size,
return file;
}
static struct vfsmount *__init mount_one_hugetlbfs(struct hstate *h)
{
struct fs_context *fc;
struct vfsmount *mnt;
fc = fs_context_for_mount(&hugetlbfs_fs_type, SB_KERNMOUNT);
if (IS_ERR(fc)) {
mnt = ERR_CAST(fc);
} else {
struct hugetlbfs_fs_context *ctx = fc->fs_private;
ctx->hstate = h;
mnt = fc_mount(fc);
put_fs_context(fc);
}
if (IS_ERR(mnt))
pr_err("Cannot mount internal hugetlbfs for page size %uK",
1U << (h->order + PAGE_SHIFT - 10));
return mnt;
}
static int __init init_hugetlbfs_fs(void)
{
struct vfsmount *mnt;
struct hstate *h;
int error;
int i;
@ -1408,24 +1458,16 @@ static int __init init_hugetlbfs_fs(void)
i = 0;
for_each_hstate(h) {
char buf[50];
unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10);
snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb);
hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type,
buf);
if (IS_ERR(hugetlbfs_vfsmount[i])) {
pr_err("Cannot mount internal hugetlbfs for "
"page size %uK", ps_kb);
error = PTR_ERR(hugetlbfs_vfsmount[i]);
hugetlbfs_vfsmount[i] = NULL;
mnt = mount_one_hugetlbfs(h);
if (IS_ERR(mnt) && i == 0) {
error = PTR_ERR(mnt);
goto out;
}
hugetlbfs_vfsmount[i] = mnt;
i++;
}
/* Non default hstates are optional */
if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx]))
return 0;
return 0;
out:
kmem_cache_destroy(hugetlbfs_inode_cachep);

13
fs/internal.h
View File

@ -17,6 +17,7 @@ struct linux_binprm;
struct path;
struct mount;
struct shrink_control;
struct fs_context;
/*
* block_dev.c
@ -51,9 +52,17 @@ int __generic_write_end(struct inode *inode, loff_t pos, unsigned copied,
*/
extern void __init chrdev_init(void);
/*
* fs_context.c
*/
extern int parse_monolithic_mount_data(struct fs_context *, void *);
extern void fc_drop_locked(struct fs_context *);
/*
* namei.c
*/
extern int filename_lookup(int dfd, struct filename *name, unsigned flags,
struct path *path, struct path *root);
extern int user_path_mountpoint_at(int, const char __user *, unsigned int, struct path *);
extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
const char *, unsigned int, struct path *);
@ -99,10 +108,8 @@ extern struct file *alloc_empty_file_noaccount(int, const struct cred *);
/*
* super.c
*/
extern int do_remount_sb(struct super_block *, int, void *, int);
extern int reconfigure_super(struct fs_context *);
extern bool trylock_super(struct super_block *sb);
extern struct dentry *mount_fs(struct file_system_type *,
int, const char *, void *);
extern struct super_block *user_get_super(dev_t);
/*

1
fs/kernfs/kernfs-internal.h
View File

@ -17,6 +17,7 @@
#include <linux/xattr.h>
#include <linux/kernfs.h>
#include <linux/fs_context.h>
struct kernfs_iattrs {
struct iattr ia_iattr;

119
fs/kernfs/mount.c
View File

@ -22,16 +22,6 @@
struct kmem_cache *kernfs_node_cache, *kernfs_iattrs_cache;
static int kernfs_sop_remount_fs(struct super_block *sb, int *flags, char *data)
{
struct kernfs_root *root = kernfs_info(sb)->root;
struct kernfs_syscall_ops *scops = root->syscall_ops;
if (scops && scops->remount_fs)
return scops->remount_fs(root, flags, data);
return 0;
}
static int kernfs_sop_show_options(struct seq_file *sf, struct dentry *dentry)
{
struct kernfs_root *root = kernfs_root(kernfs_dentry_node(dentry));
@ -60,7 +50,6 @@ const struct super_operations kernfs_sops = {
.drop_inode = generic_delete_inode,
.evict_inode = kernfs_evict_inode,
.remount_fs = kernfs_sop_remount_fs,
.show_options = kernfs_sop_show_options,
.show_path = kernfs_sop_show_path,
};
@ -222,7 +211,7 @@ struct dentry *kernfs_node_dentry(struct kernfs_node *kn,
} while (true);
}
static int kernfs_fill_super(struct super_block *sb, unsigned long magic)
static int kernfs_fill_super(struct super_block *sb, struct kernfs_fs_context *kfc)
{
struct kernfs_super_info *info = kernfs_info(sb);
struct inode *inode;
@ -233,7 +222,7 @@ static int kernfs_fill_super(struct super_block *sb, unsigned long magic)
sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
sb->s_blocksize = PAGE_SIZE;
sb->s_blocksize_bits = PAGE_SHIFT;
sb->s_magic = magic;
sb->s_magic = kfc->magic;
sb->s_op = &kernfs_sops;
sb->s_xattr = kernfs_xattr_handlers;
if (info->root->flags & KERNFS_ROOT_SUPPORT_EXPORTOP)
@ -263,21 +252,20 @@ static int kernfs_fill_super(struct super_block *sb, unsigned long magic)
return 0;
}
static int kernfs_test_super(struct super_block *sb, void *data)
static int kernfs_test_super(struct super_block *sb, struct fs_context *fc)
{
struct kernfs_super_info *sb_info = kernfs_info(sb);
struct kernfs_super_info *info = data;
struct kernfs_super_info *info = fc->s_fs_info;
return sb_info->root == info->root && sb_info->ns == info->ns;
}
static int kernfs_set_super(struct super_block *sb, void *data)
static int kernfs_set_super(struct super_block *sb, struct fs_context *fc)
{
int error;
error = set_anon_super(sb, data);
if (!error)
sb->s_fs_info = data;
return error;
struct kernfs_fs_context *kfc = fc->fs_private;
kfc->ns_tag = NULL;
return set_anon_super_fc(sb, fc);
}
/**
@ -294,63 +282,60 @@ const void *kernfs_super_ns(struct super_block *sb)
}
/**
* kernfs_mount_ns - kernfs mount helper
* @fs_type: file_system_type of the fs being mounted
* @flags: mount flags specified for the mount
* @root: kernfs_root of the hierarchy being mounted
* @magic: file system specific magic number
* @new_sb_created: tell the caller if we allocated a new superblock
* @ns: optional namespace tag of the mount
* kernfs_get_tree - kernfs filesystem access/retrieval helper
* @fc: The filesystem context.
*
* This is to be called from each kernfs user's file_system_type->mount()
* implementation, which should pass through the specified @fs_type and
* @flags, and specify the hierarchy and namespace tag to mount via @root
* and @ns, respectively.
*
* The return value can be passed to the vfs layer verbatim.
* This is to be called from each kernfs user's fs_context->ops->get_tree()
* implementation, which should set the specified ->@fs_type and ->@flags, and
* specify the hierarchy and namespace tag to mount via ->@root and ->@ns,
* respectively.
*/
struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
struct kernfs_root *root, unsigned long magic,
bool *new_sb_created, const void *ns)
int kernfs_get_tree(struct fs_context *fc)
{
struct kernfs_fs_context *kfc = fc->fs_private;
struct super_block *sb;
struct kernfs_super_info *info;
int error;
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (!info)
return ERR_PTR(-ENOMEM);
return -ENOMEM;
info->root = root;
info->ns = ns;
info->root = kfc->root;
info->ns = kfc->ns_tag;
INIT_LIST_HEAD(&info->node);
sb = sget_userns(fs_type, kernfs_test_super, kernfs_set_super, flags,
&init_user_ns, info);
if (IS_ERR(sb) || sb->s_fs_info != info)
kfree(info);
fc->s_fs_info = info;
sb = sget_fc(fc, kernfs_test_super, kernfs_set_super);
if (IS_ERR(sb))
return ERR_CAST(sb);
if (new_sb_created)
*new_sb_created = !sb->s_root;
return PTR_ERR(sb);
if (!sb->s_root) {
struct kernfs_super_info *info = kernfs_info(sb);
error = kernfs_fill_super(sb, magic);
kfc->new_sb_created = true;
error = kernfs_fill_super(sb, kfc);
if (error) {
deactivate_locked_super(sb);
return ERR_PTR(error);
return error;
}
sb->s_flags |= SB_ACTIVE;
mutex_lock(&kernfs_mutex);
list_add(&info->node, &root->supers);
list_add(&info->node, &info->root->supers);
mutex_unlock(&kernfs_mutex);
}
return dget(sb->s_root);
fc->root = dget(sb->s_root);
return 0;
}
void kernfs_free_fs_context(struct fs_context *fc)
{
/* Note that we don't deal with kfc->ns_tag here. */
kfree(fc->s_fs_info);
fc->s_fs_info = NULL;
}
/**
@ -377,36 +362,6 @@ void kernfs_kill_sb(struct super_block *sb)
kfree(info);
}
/**
* kernfs_pin_sb: try to pin the superblock associated with a kernfs_root
* @kernfs_root: the kernfs_root in question
* @ns: the namespace tag
*
* Pin the superblock so the superblock won't be destroyed in subsequent
* operations. This can be used to block ->kill_sb() which may be useful
* for kernfs users which dynamically manage superblocks.
*
* Returns NULL if there's no superblock associated to this kernfs_root, or
* -EINVAL if the superblock is being freed.
*/
struct super_block *kernfs_pin_sb(struct kernfs_root *root, const void *ns)
{
struct kernfs_super_info *info;
struct super_block *sb = NULL;
mutex_lock(&kernfs_mutex);
list_for_each_entry(info, &root->supers, node) {
if (info->ns == ns) {
sb = info->sb;
if (!atomic_inc_not_zero(&info->sb->s_active))
sb = ERR_PTR(-EINVAL);
break;
}
}
mutex_unlock(&kernfs_mutex);
return sb;
}
void __init kernfs_init(void)
{

5
fs/mount.h
View File

@ -146,3 +146,8 @@ static inline bool is_local_mountpoint(struct dentry *dentry)
return __is_local_mountpoint(dentry);
}
static inline bool is_anon_ns(struct mnt_namespace *ns)
{
return ns->seq == 0;
}

4
fs/namei.c
View File

@ -2331,8 +2331,8 @@ static int path_lookupat(struct nameidata *nd, unsigned flags, struct path *path
return err;
}
static int filename_lookup(int dfd, struct filename *name, unsigned flags,
struct path *path, struct path *root)
int filename_lookup(int dfd, struct filename *name, unsigned flags,
struct path *path, struct path *root)
{
int retval;
struct nameidata nd;

397
fs/namespace.c
View File

@ -27,6 +27,7 @@
#include <linux/task_work.h>
#include <linux/sched/task.h>
#include <uapi/linux/mount.h>
#include <linux/fs_context.h>
#include "pnode.h"
#include "internal.h"
@ -940,38 +941,81 @@ static struct mount *skip_mnt_tree(struct mount *p)
return p;
}
struct vfsmount *
vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)
/**
* vfs_create_mount - Create a mount for a configured superblock
* @fc: The configuration context with the superblock attached
*
* Create a mount to an already configured superblock. If necessary, the
* caller should invoke vfs_get_tree() before calling this.
*
* Note that this does not attach the mount to anything.
*/
struct vfsmount *vfs_create_mount(struct fs_context *fc)
{
struct mount *mnt;
struct dentry *root;
if (!type)
return ERR_PTR(-ENODEV);
if (!fc->root)
return ERR_PTR(-EINVAL);
mnt = alloc_vfsmnt(name);
mnt = alloc_vfsmnt(fc->source ?: "none");
if (!mnt)
return ERR_PTR(-ENOMEM);
if (flags & SB_KERNMOUNT)
if (fc->sb_flags & SB_KERNMOUNT)
mnt->mnt.mnt_flags = MNT_INTERNAL;
root = mount_fs(type, flags, name, data);
if (IS_ERR(root)) {
mnt_free_id(mnt);
free_vfsmnt(mnt);
return ERR_CAST(root);
}
atomic_inc(&fc->root->d_sb->s_active);
mnt->mnt.mnt_sb = fc->root->d_sb;
mnt->mnt.mnt_root = dget(fc->root);
mnt->mnt_mountpoint = mnt->mnt.mnt_root;
mnt->mnt_parent = mnt;
mnt->mnt.mnt_root = root;
mnt->mnt.mnt_sb = root->d_sb;
mnt->mnt_mountpoint = mnt->mnt.mnt_root;
mnt->mnt_parent = mnt;
lock_mount_hash();
list_add_tail(&mnt->mnt_instance, &root->d_sb->s_mounts);
list_add_tail(&mnt->mnt_instance, &mnt->mnt.mnt_sb->s_mounts);
unlock_mount_hash();
return &mnt->mnt;
}
EXPORT_SYMBOL(vfs_create_mount);
struct vfsmount *fc_mount(struct fs_context *fc)
{
int err = vfs_get_tree(fc);
if (!err) {
up_write(&fc->root->d_sb->s_umount);
return vfs_create_mount(fc);
}
return ERR_PTR(err);
}
EXPORT_SYMBOL(fc_mount);
struct vfsmount *vfs_kern_mount(struct file_system_type *type,
int flags, const char *name,
void *data)
{
struct fs_context *fc;
struct vfsmount *mnt;
int ret = 0;
if (!type)
return ERR_PTR(-EINVAL);
fc = fs_context_for_mount(type, flags);
if (IS_ERR(fc))
return ERR_CAST(fc);
if (name)
ret = vfs_parse_fs_string(fc, "source",
name, strlen(name));
if (!ret)
ret = parse_monolithic_mount_data(fc, data);
if (!ret)
mnt = fc_mount(fc);
else
mnt = ERR_PTR(ret);
put_fs_context(fc);
return mnt;
}
EXPORT_SYMBOL_GPL(vfs_kern_mount);
struct vfsmount *
@ -1013,27 +1057,6 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
mnt->mnt.mnt_flags = old->mnt.mnt_flags;
mnt->mnt.mnt_flags &= ~(MNT_WRITE_HOLD|MNT_MARKED|MNT_INTERNAL);
/* Don't allow unprivileged users to change mount flags */
if (flag & CL_UNPRIVILEGED) {
mnt->mnt.mnt_flags |= MNT_LOCK_ATIME;
if (mnt->mnt.mnt_flags & MNT_READONLY)
mnt->mnt.mnt_flags |= MNT_LOCK_READONLY;
if (mnt->mnt.mnt_flags & MNT_NODEV)
mnt->mnt.mnt_flags |= MNT_LOCK_NODEV;
if (mnt->mnt.mnt_flags & MNT_NOSUID)
mnt->mnt.mnt_flags |= MNT_LOCK_NOSUID;
if (mnt->mnt.mnt_flags & MNT_NOEXEC)
mnt->mnt.mnt_flags |= MNT_LOCK_NOEXEC;
}
/* Don't allow unprivileged users to reveal what is under a mount */
if ((flag & CL_UNPRIVILEGED) &&
(!(flag & CL_EXPIRE) || list_empty(&old->mnt_expire)))
mnt->mnt.mnt_flags |= MNT_LOCKED;
atomic_inc(&sb->s_active);
mnt->mnt.mnt_sb = sb;
@ -1464,6 +1487,29 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
static void shrink_submounts(struct mount *mnt);
static int do_umount_root(struct super_block *sb)
{
int ret = 0;
down_write(&sb->s_umount);
if (!sb_rdonly(sb)) {
struct fs_context *fc;
fc = fs_context_for_reconfigure(sb->s_root, SB_RDONLY,
SB_RDONLY);
if (IS_ERR(fc)) {
ret = PTR_ERR(fc);
} else {
ret = parse_monolithic_mount_data(fc, NULL);
if (!ret)
ret = reconfigure_super(fc);
put_fs_context(fc);
}
}
up_write(&sb->s_umount);
return ret;
}
static int do_umount(struct mount *mnt, int flags)
{
struct super_block *sb = mnt->mnt.mnt_sb;
@ -1529,11 +1575,7 @@ static int do_umount(struct mount *mnt, int flags)
*/
if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
return -EPERM;
down_write(&sb->s_umount);
if (!sb_rdonly(sb))
retval = do_remount_sb(sb, SB_RDONLY, NULL, 0);
up_write(&sb->s_umount);
return retval;
return do_umount_root(sb);
}
namespace_lock();
@ -1839,6 +1881,33 @@ int iterate_mounts(int (*f)(struct vfsmount *, void *), void *arg,
return 0;
}
static void lock_mnt_tree(struct mount *mnt)
{
struct mount *p;
for (p = mnt; p; p = next_mnt(p, mnt)) {
int flags = p->mnt.mnt_flags;
/* Don't allow unprivileged users to change mount flags */
flags |= MNT_LOCK_ATIME;
if (flags & MNT_READONLY)
flags |= MNT_LOCK_READONLY;
if (flags & MNT_NODEV)
flags |= MNT_LOCK_NODEV;
if (flags & MNT_NOSUID)
flags |= MNT_LOCK_NOSUID;
if (flags & MNT_NOEXEC)
flags |= MNT_LOCK_NOEXEC;
/* Don't allow unprivileged users to reveal what is under a mount */
if (list_empty(&p->mnt_expire))
flags |= MNT_LOCKED;
p->mnt.mnt_flags = flags;
}
}
static void cleanup_group_ids(struct mount *mnt, struct mount *end)
{
struct mount *p;
@ -1956,6 +2025,7 @@ static int attach_recursive_mnt(struct mount *source_mnt,
struct mountpoint *dest_mp,
struct path *parent_path)
{
struct user_namespace *user_ns = current->nsproxy->mnt_ns->user_ns;
HLIST_HEAD(tree_list);
struct mnt_namespace *ns = dest_mnt->mnt_ns;
struct mountpoint *smp;
@ -2006,6 +2076,9 @@ static int attach_recursive_mnt(struct mount *source_mnt,
child->mnt_mountpoint);
if (q)
mnt_change_mountpoint(child, smp, q);
/* Notice when we are propagating across user namespaces */
if (child->mnt_parent->mnt_ns->user_ns != user_ns)
lock_mnt_tree(child);
commit_tree(child);
}
put_mountpoint(smp);
@ -2313,7 +2386,7 @@ static int do_remount(struct path *path, int ms_flags, int sb_flags,
int err;
struct super_block *sb = path->mnt->mnt_sb;
struct mount *mnt = real_mount(path->mnt);
void *sec_opts = NULL;
struct fs_context *fc;
if (!check_mnt(mnt))
return -EINVAL;
@ -2324,24 +2397,22 @@ static int do_remount(struct path *path, int ms_flags, int sb_flags,
if (!can_change_locked_flags(mnt, mnt_flags))
return -EPERM;
if (data && !(sb->s_type->fs_flags & FS_BINARY_MOUNTDATA)) {
err = security_sb_eat_lsm_opts(data, &sec_opts);
if (err)
return err;
}
err = security_sb_remount(sb, sec_opts);
security_free_mnt_opts(&sec_opts);
if (err)
return err;
fc = fs_context_for_reconfigure(path->dentry, sb_flags, MS_RMT_MASK);
if (IS_ERR(fc))
return PTR_ERR(fc);
down_write(&sb->s_umount);
err = -EPERM;
if (ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) {
err = do_remount_sb(sb, sb_flags, data, 0);
if (!err)
set_mount_attributes(mnt, mnt_flags);
err = parse_monolithic_mount_data(fc, data);
if (!err) {
down_write(&sb->s_umount);
err = -EPERM;
if (ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) {
err = reconfigure_super(fc);
if (!err)
set_mount_attributes(mnt, mnt_flags);
}
up_write(&sb->s_umount);
}
up_write(&sb->s_umount);
put_fs_context(fc);
return err;
}
@ -2425,29 +2496,6 @@ static int do_move_mount(struct path *path, const char *old_name)
return err;
}
static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)
{
int err;
const char *subtype = strchr(fstype, '.');
if (subtype) {
subtype++;
err = -EINVAL;
if (!subtype[0])
goto err;
} else
subtype = "";
mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL);
err = -ENOMEM;
if (!mnt->mnt_sb->s_subtype)
goto err;
return mnt;
err:
mntput(mnt);
return ERR_PTR(err);
}
/*
* add a mount into a namespace's mount tree
*/
@ -2492,7 +2540,39 @@ static int do_add_mount(struct mount *newmnt, struct path *path, int mnt_flags)
return err;
}
static bool mount_too_revealing(struct vfsmount *mnt, int *new_mnt_flags);
static bool mount_too_revealing(const struct super_block *sb, int *new_mnt_flags);
/*
* Create a new mount using a superblock configuration and request it
* be added to the namespace tree.
*/
static int do_new_mount_fc(struct fs_context *fc, struct path *mountpoint,
unsigned int mnt_flags)
{
struct vfsmount *mnt;
struct super_block *sb = fc->root->d_sb;
int error;
error = security_sb_kern_mount(sb);
if (!error && mount_too_revealing(sb, &mnt_flags))
error = -EPERM;
if (unlikely(error)) {
fc_drop_locked(fc);
return error;
}
up_write(&sb->s_umount);
mnt = vfs_create_mount(fc);
if (IS_ERR(mnt))
return PTR_ERR(mnt);
error = do_add_mount(real_mount(mnt), mountpoint, mnt_flags);
if (error < 0)
mntput(mnt);
return error;
}
/*
* create a new mount for userspace and request it to be added into the
@ -2502,8 +2582,9 @@ static int do_new_mount(struct path *path, const char *fstype, int sb_flags,
int mnt_flags, const char *name, void *data)
{
struct file_system_type *type;
struct vfsmount *mnt;
int err;
struct fs_context *fc;
const char *subtype = NULL;
int err = 0;
if (!fstype)
return -EINVAL;
@ -2512,23 +2593,37 @@ static int do_new_mount(struct path *path, const char *fstype, int sb_flags,
if (!type)
return -ENODEV;
mnt = vfs_kern_mount(type, sb_flags, name, data);
if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&
!mnt->mnt_sb->s_subtype)
mnt = fs_set_subtype(mnt, fstype);
put_filesystem(type);
if (IS_ERR(mnt))
return PTR_ERR(mnt);
if (mount_too_revealing(mnt, &mnt_flags)) {
mntput(mnt);
return -EPERM;
if (type->fs_flags & FS_HAS_SUBTYPE) {
subtype = strchr(fstype, '.');
if (subtype) {
subtype++;
if (!*subtype) {
put_filesystem(type);
return -EINVAL;
}
} else {
subtype = "";
}
}
err = do_add_mount(real_mount(mnt), path, mnt_flags);
if (err)
mntput(mnt);
fc = fs_context_for_mount(type, sb_flags);
put_filesystem(type);
if (IS_ERR(fc))
return PTR_ERR(fc);
if (subtype)
err = vfs_parse_fs_string(fc, "subtype",
subtype, strlen(subtype));
if (!err && name)
err = vfs_parse_fs_string(fc, "source", name, strlen(name));
if (!err)
err = parse_monolithic_mount_data(fc, data);
if (!err)
err = vfs_get_tree(fc);
if (!err)
err = do_new_mount_fc(fc, path, mnt_flags);
put_fs_context(fc);
return err;
}
@ -2863,7 +2958,8 @@ static void dec_mnt_namespaces(struct ucounts *ucounts)
static void free_mnt_ns(struct mnt_namespace *ns)
{
ns_free_inum(&ns->ns);
if (!is_anon_ns(ns))
ns_free_inum(&ns->ns);
dec_mnt_namespaces(ns->ucounts);
put_user_ns(ns->user_ns);
kfree(ns);
@ -2878,7 +2974,7 @@ static void free_mnt_ns(struct mnt_namespace *ns)
*/
static atomic64_t mnt_ns_seq = ATOMIC64_INIT(1);
static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns)
static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns, bool anon)
{
struct mnt_namespace *new_ns;
struct ucounts *ucounts;
@ -2888,28 +2984,27 @@ static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns)
if (!ucounts)
return ERR_PTR(-ENOSPC);
new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL);
new_ns = kzalloc(sizeof(struct mnt_namespace), GFP_KERNEL);
if (!new_ns) {
dec_mnt_namespaces(ucounts);
return ERR_PTR(-ENOMEM);
}
ret = ns_alloc_inum(&new_ns->ns);
if (ret) {
kfree(new_ns);
dec_mnt_namespaces(ucounts);
return ERR_PTR(ret);
if (!anon) {
ret = ns_alloc_inum(&new_ns->ns);
if (ret) {
kfree(new_ns);
dec_mnt_namespaces(ucounts);
return ERR_PTR(ret);
}
}
new_ns->ns.ops = &mntns_operations;
new_ns->seq = atomic64_add_return(1, &mnt_ns_seq);
if (!anon)
new_ns->seq = atomic64_add_return(1, &mnt_ns_seq);
atomic_set(&new_ns->count, 1);
new_ns->root = NULL;
INIT_LIST_HEAD(&new_ns->list);
init_waitqueue_head(&new_ns->poll);
new_ns->event = 0;
new_ns->user_ns = get_user_ns(user_ns);
new_ns->ucounts = ucounts;
new_ns->mounts = 0;
new_ns->pending_mounts = 0;
return new_ns;
}
@ -2933,7 +3028,7 @@ struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns,
old = ns->root;
new_ns = alloc_mnt_ns(user_ns);
new_ns = alloc_mnt_ns(user_ns, false);
if (IS_ERR(new_ns))
return new_ns;
@ -2941,13 +3036,18 @@ struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns,
/* First pass: copy the tree topology */
copy_flags = CL_COPY_UNBINDABLE | CL_EXPIRE;
if (user_ns != ns->user_ns)
copy_flags |= CL_SHARED_TO_SLAVE | CL_UNPRIVILEGED;
copy_flags |= CL_SHARED_TO_SLAVE;
new = copy_tree(old, old->mnt.mnt_root, copy_flags);
if (IS_ERR(new)) {
namespace_unlock();
free_mnt_ns(new_ns);
return ERR_CAST(new);
}
if (user_ns != ns->user_ns) {
lock_mount_hash();
lock_mnt_tree(new);
unlock_mount_hash();
}
new_ns->root = new;
list_add_tail(&new_ns->list, &new->mnt_list);
@ -2988,37 +3088,25 @@ struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns,
return new_ns;
}
/**
* create_mnt_ns - creates a private namespace and adds a root filesystem
* @mnt: pointer to the new root filesystem mountpoint
*/
static struct mnt_namespace *create_mnt_ns(struct vfsmount *m)
{
struct mnt_namespace *new_ns = alloc_mnt_ns(&init_user_ns);
if (!IS_ERR(new_ns)) {
struct mount *mnt = real_mount(m);
mnt->mnt_ns = new_ns;
new_ns->root = mnt;
new_ns->mounts++;
list_add(&mnt->mnt_list, &new_ns->list);
} else {
mntput(m);
}
return new_ns;
}
struct dentry *mount_subtree(struct vfsmount *mnt, const char *name)
struct dentry *mount_subtree(struct vfsmount *m, const char *name)
{
struct mount *mnt = real_mount(m);
struct mnt_namespace *ns;
struct super_block *s;
struct path path;
int err;
ns = create_mnt_ns(mnt);
if (IS_ERR(ns))
ns = alloc_mnt_ns(&init_user_ns, true);
if (IS_ERR(ns)) {
mntput(m);
return ERR_CAST(ns);
}
mnt->mnt_ns = ns;
ns->root = mnt;
ns->mounts++;
list_add(&mnt->mnt_list, &ns->list);
err = vfs_path_lookup(mnt->mnt_root, mnt,
err = vfs_path_lookup(m->mnt_root, m,
name, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
put_mnt_ns(ns);
@ -3228,6 +3316,7 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
static void __init init_mount_tree(void)
{
struct vfsmount *mnt;
struct mount *m;
struct mnt_namespace *ns;
struct path root;
struct file_system_type *type;
@ -3240,10 +3329,14 @@ static void __init init_mount_tree(void)
if (IS_ERR(mnt))
panic("Can't create rootfs");
ns = create_mnt_ns(mnt);
ns = alloc_mnt_ns(&init_user_ns, false);
if (IS_ERR(ns))
panic("Can't allocate initial namespace");
m = real_mount(mnt);
m->mnt_ns = ns;
ns->root = m;
ns->mounts = 1;
list_add(&m->mnt_list, &ns->list);
init_task.nsproxy->mnt_ns = ns;
get_mnt_ns(ns);
@ -3297,10 +3390,10 @@ void put_mnt_ns(struct mnt_namespace *ns)
free_mnt_ns(ns);
}
struct vfsmount *kern_mount_data(struct file_system_type *type, void *data)
struct vfsmount *kern_mount(struct file_system_type *type)
{
struct vfsmount *mnt;
mnt = vfs_kern_mount(type, SB_KERNMOUNT, type->name, data);
mnt = vfs_kern_mount(type, SB_KERNMOUNT, type->name, NULL);
if (!IS_ERR(mnt)) {
/*
* it is a longterm mount, don't release mnt until
@ -3310,7 +3403,7 @@ struct vfsmount *kern_mount_data(struct file_system_type *type, void *data)
}
return mnt;
}
EXPORT_SYMBOL_GPL(kern_mount_data);
EXPORT_SYMBOL_GPL(kern_mount);
void kern_unmount(struct vfsmount *mnt)
{
@ -3352,7 +3445,8 @@ bool current_chrooted(void)
return chrooted;
}
static bool mnt_already_visible(struct mnt_namespace *ns, struct vfsmount *new,
static bool mnt_already_visible(struct mnt_namespace *ns,
const struct super_block *sb,
int *new_mnt_flags)
{
int new_flags = *new_mnt_flags;
@ -3364,7 +3458,7 @@ static bool mnt_already_visible(struct mnt_namespace *ns, struct vfsmount *new,
struct mount *child;
int mnt_flags;
if (mnt->mnt.mnt_sb->s_type != new->mnt_sb->s_type)
if (mnt->mnt.mnt_sb->s_type != sb->s_type)
continue;
/* This mount is not fully visible if it's root directory
@ -3415,7 +3509,7 @@ static bool mnt_already_visible(struct mnt_namespace *ns, struct vfsmount *new,
return visible;
}
static bool mount_too_revealing(struct vfsmount *mnt, int *new_mnt_flags)
static bool mount_too_revealing(const struct super_block *sb, int *new_mnt_flags)
{
const unsigned long required_iflags = SB_I_NOEXEC | SB_I_NODEV;
struct mnt_namespace *ns = current->nsproxy->mnt_ns;
@ -3425,7 +3519,7 @@ static bool mount_too_revealing(struct vfsmount *mnt, int *new_mnt_flags)
return false;
/* Can this filesystem be too revealing? */
s_iflags = mnt->mnt_sb->s_iflags;
s_iflags = sb->s_iflags;
if (!(s_iflags & SB_I_USERNS_VISIBLE))
return false;
@ -3435,7 +3529,7 @@ static bool mount_too_revealing(struct vfsmount *mnt, int *new_mnt_flags)
return true;
}
return !mnt_already_visible(ns, mnt, new_mnt_flags);
return !mnt_already_visible(ns, sb, new_mnt_flags);
}
bool mnt_may_suid(struct vfsmount *mnt)
@ -3484,6 +3578,9 @@ static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns)
!ns_capable(current_user_ns(), CAP_SYS_ADMIN))
return -EPERM;
if (is_anon_ns(mnt_ns))
return -EINVAL;
if (fs->users != 1)
return -EINVAL;

5
fs/pnode.c
View File

@ -214,7 +214,6 @@ static struct mount *next_group(struct mount *m, struct mount *origin)
}
/* all accesses are serialized by namespace_sem */
static struct user_namespace *user_ns;
static struct mount *last_dest, *first_source, *last_source, *dest_master;
static struct mountpoint *mp;
static struct hlist_head *list;
@ -260,9 +259,6 @@ static int propagate_one(struct mount *m)
type |= CL_MAKE_SHARED;
}
/* Notice when we are propagating across user namespaces */
if (m->mnt_ns->user_ns != user_ns)
type |= CL_UNPRIVILEGED;
child = copy_tree(last_source, last_source->mnt.mnt_root, type);
if (IS_ERR(child))
return PTR_ERR(child);
@ -303,7 +299,6 @@ int propagate_mnt(struct mount *dest_mnt, struct mountpoint *dest_mp,
* propagate_one(); everything is serialized by namespace_sem,
* so globals will do just fine.
*/
user_ns = current->nsproxy->mnt_ns->user_ns;
last_dest = dest_mnt;
first_source = source_mnt;
last_source = source_mnt;

3
fs/pnode.h
View File

@ -27,8 +27,7 @@
#define CL_MAKE_SHARED 0x08
#define CL_PRIVATE 0x10
#define CL_SHARED_TO_SLAVE 0x20
#define CL_UNPRIVILEGED 0x40
#define CL_COPY_MNT_NS_FILE 0x80
#define CL_COPY_MNT_NS_FILE 0x40
#define CL_COPY_ALL (CL_COPY_UNBINDABLE | CL_COPY_MNT_NS_FILE)

52
fs/proc/inode.c
View File

@ -24,7 +24,6 @@
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/mount.h>
#include <linux/magic.h>
#include <linux/uaccess.h>
@ -122,13 +121,12 @@ static int proc_show_options(struct seq_file *seq, struct dentry *root)
return 0;
}
static const struct super_operations proc_sops = {
const struct super_operations proc_sops = {
.alloc_inode = proc_alloc_inode,
.destroy_inode = proc_destroy_inode,
.drop_inode = generic_delete_inode,
.evict_inode = proc_evict_inode,
.statfs = simple_statfs,
.remount_fs = proc_remount,
.show_options = proc_show_options,
};
@ -488,51 +486,3 @@ struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
pde_put(de);
return inode;
}
int proc_fill_super(struct super_block *s, void *data, int silent)
{
struct pid_namespace *ns = get_pid_ns(s->s_fs_info);
struct inode *root_inode;
int ret;
if (!proc_parse_options(data, ns))
return -EINVAL;
/* User space would break if executables or devices appear on proc */
s->s_iflags |= SB_I_USERNS_VISIBLE | SB_I_NOEXEC | SB_I_NODEV;
s->s_flags |= SB_NODIRATIME | SB_NOSUID | SB_NOEXEC;
s->s_blocksize = 1024;
s->s_blocksize_bits = 10;
s->s_magic = PROC_SUPER_MAGIC;
s->s_op = &proc_sops;
s->s_time_gran = 1;
/*
* procfs isn't actually a stacking filesystem; however, there is
* too much magic going on inside it to permit stacking things on
* top of it
*/
s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
/* procfs dentries and inodes don't require IO to create */
s->s_shrink.seeks = 0;
pde_get(&proc_root);
root_inode = proc_get_inode(s, &proc_root);
if (!root_inode) {
pr_err("proc_fill_super: get root inode failed\n");
return -ENOMEM;
}
s->s_root = d_make_root(root_inode);
if (!s->s_root) {
pr_err("proc_fill_super: allocate dentry failed\n");
return -ENOMEM;
}
ret = proc_setup_self(s);
if (ret) {
return ret;
}
return proc_setup_thread_self(s);
}

5
fs/proc/internal.h
View File

@ -207,13 +207,12 @@ struct pde_opener {
struct completion *c;
} __randomize_layout;
extern const struct inode_operations proc_link_inode_operations;
extern const struct inode_operations proc_pid_link_inode_operations;
extern const struct super_operations proc_sops;
void proc_init_kmemcache(void);
void set_proc_pid_nlink(void);
extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *);
extern int proc_fill_super(struct super_block *, void *data, int flags);
extern void proc_entry_rundown(struct proc_dir_entry *);
/*
@ -271,10 +270,8 @@ static inline void proc_tty_init(void) {}
* root.c
*/
extern struct proc_dir_entry proc_root;
extern int proc_parse_options(char *options, struct pid_namespace *pid);
extern void proc_self_init(void);
extern int proc_remount(struct super_block *, int *, char *);
/*
* task_[no]mmu.c

230
fs/proc/root.c
View File

@ -19,86 +19,178 @@
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/user_namespace.h>
#include <linux/fs_context.h>
#include <linux/mount.h>
#include <linux/pid_namespace.h>
#include <linux/parser.h>
#include <linux/fs_parser.h>
#include <linux/cred.h>
#include <linux/magic.h>
#include <linux/slab.h>
#include "internal.h"
enum {
Opt_gid, Opt_hidepid, Opt_err,
struct proc_fs_context {
struct pid_namespace *pid_ns;
unsigned int mask;
int hidepid;
int gid;
};
static const match_table_t tokens = {
{Opt_hidepid, "hidepid=%u"},
{Opt_gid, "gid=%u"},
{Opt_err, NULL},
enum proc_param {
Opt_gid,
Opt_hidepid,
};
int proc_parse_options(char *options, struct pid_namespace *pid)
static const struct fs_parameter_spec proc_param_specs[] = {
fsparam_u32("gid", Opt_gid),
fsparam_u32("hidepid", Opt_hidepid),
{}
};
static const struct fs_parameter_description proc_fs_parameters = {
.name = "proc",
.specs = proc_param_specs,
};
static int proc_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
char *p;
substring_t args[MAX_OPT_ARGS];
int option;
struct proc_fs_context *ctx = fc->fs_private;
struct fs_parse_result result;
int opt;
if (!options)
return 1;
opt = fs_parse(fc, &proc_fs_parameters, param, &result);
if (opt < 0)
return opt;
while ((p = strsep(&options, ",")) != NULL) {
int token;
if (!*p)
continue;
switch (opt) {
case Opt_gid:
ctx->gid = result.uint_32;
break;
args[0].to = args[0].from = NULL;
token = match_token(p, tokens, args);
switch (token) {
case Opt_gid:
if (match_int(&args[0], &option))
return 0;
pid->pid_gid = make_kgid(current_user_ns(), option);
break;
case Opt_hidepid:
if (match_int(&args[0], &option))
return 0;
if (option < HIDEPID_OFF ||
option > HIDEPID_INVISIBLE) {
pr_err("proc: hidepid value must be between 0 and 2.\n");
return 0;
}
pid->hide_pid = option;
break;
default:
pr_err("proc: unrecognized mount option \"%s\" "
"or missing value\n", p);
return 0;
}
case Opt_hidepid:
ctx->hidepid = result.uint_32;
if (ctx->hidepid < HIDEPID_OFF ||
ctx->hidepid > HIDEPID_INVISIBLE)
return invalf(fc, "proc: hidepid value must be between 0 and 2.\n");
break;
default:
return -EINVAL;
}
return 1;
ctx->mask |= 1 << opt;
return 0;
}
int proc_remount(struct super_block *sb, int *flags, char *data)
static void proc_apply_options(struct super_block *s,
struct fs_context *fc,
struct pid_namespace *pid_ns,
struct user_namespace *user_ns)
{
struct proc_fs_context *ctx = fc->fs_private;
if (ctx->mask & (1 << Opt_gid))
pid_ns->pid_gid = make_kgid(user_ns, ctx->gid);
if (ctx->mask & (1 << Opt_hidepid))
pid_ns->hide_pid = ctx->hidepid;
}
static int proc_fill_super(struct super_block *s, struct fs_context *fc)
{
struct pid_namespace *pid_ns = get_pid_ns(s->s_fs_info);
struct inode *root_inode;
int ret;
proc_apply_options(s, fc, pid_ns, current_user_ns());
/* User space would break if executables or devices appear on proc */
s->s_iflags |= SB_I_USERNS_VISIBLE | SB_I_NOEXEC | SB_I_NODEV;
s->s_flags |= SB_NODIRATIME | SB_NOSUID | SB_NOEXEC;
s->s_blocksize = 1024;
s->s_blocksize_bits = 10;
s->s_magic = PROC_SUPER_MAGIC;
s->s_op = &proc_sops;
s->s_time_gran = 1;
/*
* procfs isn't actually a stacking filesystem; however, there is
* too much magic going on inside it to permit stacking things on
* top of it
*/
s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
/* procfs dentries and inodes don't require IO to create */
s->s_shrink.seeks = 0;
pde_get(&proc_root);
root_inode = proc_get_inode(s, &proc_root);
if (!root_inode) {
pr_err("proc_fill_super: get root inode failed\n");
return -ENOMEM;
}
s->s_root = d_make_root(root_inode);
if (!s->s_root) {
pr_err("proc_fill_super: allocate dentry failed\n");
return -ENOMEM;
}
ret = proc_setup_self(s);
if (ret) {
return ret;
}
return proc_setup_thread_self(s);
}
static int proc_reconfigure(struct fs_context *fc)
{
struct super_block *sb = fc->root->d_sb;
struct pid_namespace *pid = sb->s_fs_info;
sync_filesystem(sb);
return !proc_parse_options(data, pid);
proc_apply_options(sb, fc, pid, current_user_ns());
return 0;
}
static struct dentry *proc_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
static int proc_get_tree(struct fs_context *fc)
{
struct pid_namespace *ns;
struct proc_fs_context *ctx = fc->fs_private;
if (flags & SB_KERNMOUNT) {
ns = data;
data = NULL;
} else {
ns = task_active_pid_ns(current);
}
put_user_ns(fc->user_ns);
fc->user_ns = get_user_ns(ctx->pid_ns->user_ns);
fc->s_fs_info = ctx->pid_ns;
return vfs_get_super(fc, vfs_get_keyed_super, proc_fill_super);
}
return mount_ns(fs_type, flags, data, ns, ns->user_ns, proc_fill_super);
static void proc_fs_context_free(struct fs_context *fc)
{
struct proc_fs_context *ctx = fc->fs_private;
if (ctx->pid_ns)
put_pid_ns(ctx->pid_ns);
kfree(ctx);
}
static const struct fs_context_operations proc_fs_context_ops = {
.free = proc_fs_context_free,
.parse_param = proc_parse_param,
.get_tree = proc_get_tree,
.reconfigure = proc_reconfigure,
};
static int proc_init_fs_context(struct fs_context *fc)
{
struct proc_fs_context *ctx;
ctx = kzalloc(sizeof(struct proc_fs_context), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->pid_ns = get_pid_ns(task_active_pid_ns(current));
fc->fs_private = ctx;
fc->ops = &proc_fs_context_ops;
return 0;
}
static void proc_kill_sb(struct super_block *sb)
@ -115,10 +207,11 @@ static void proc_kill_sb(struct super_block *sb)
}
static struct file_system_type proc_fs_type = {
.name = "proc",
.mount = proc_mount,
.kill_sb = proc_kill_sb,
.fs_flags = FS_USERNS_MOUNT,
.name = "proc",
.init_fs_context = proc_init_fs_context,
.parameters = &proc_fs_parameters,
.kill_sb = proc_kill_sb,
.fs_flags = FS_USERNS_MOUNT,
};
void __init proc_root_init(void)
@ -156,7 +249,7 @@ static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentr
{
if (!proc_pid_lookup(dentry, flags))
return NULL;
return proc_lookup(dir, dentry, flags);
}
@ -209,9 +302,28 @@ struct proc_dir_entry proc_root = {
int pid_ns_prepare_proc(struct pid_namespace *ns)
{
struct proc_fs_context *ctx;
struct fs_context *fc;
struct vfsmount *mnt;
mnt = kern_mount_data(&proc_fs_type, ns);
fc = fs_context_for_mount(&proc_fs_type, SB_KERNMOUNT);
if (IS_ERR(fc))
return PTR_ERR(fc);
if (fc->user_ns != ns->user_ns) {
put_user_ns(fc->user_ns);
fc->user_ns = get_user_ns(ns->user_ns);
}
ctx = fc->fs_private;
if (ctx->pid_ns != ns) {
put_pid_ns(ctx->pid_ns);
get_pid_ns(ns);
ctx->pid_ns = ns;
}
mnt = fc_mount(fc);
put_fs_context(fc);
if (IS_ERR(mnt))
return PTR_ERR(mnt);

344
fs/super.c
View File

@ -35,6 +35,7 @@
#include <linux/fsnotify.h>
#include <linux/lockdep.h>
#include <linux/user_namespace.h>
#include <linux/fs_context.h>
#include <uapi/linux/mount.h>
#include "internal.h"
@ -475,6 +476,94 @@ void generic_shutdown_super(struct super_block *sb)
EXPORT_SYMBOL(generic_shutdown_super);
/**
* sget_fc - Find or create a superblock
* @fc: Filesystem context.
* @test: Comparison callback
* @set: Setup callback
*
* Find or create a superblock using the parameters stored in the filesystem
* context and the two callback functions.
*
* If an extant superblock is matched, then that will be returned with an
* elevated reference count that the caller must transfer or discard.
*
* If no match is made, a new superblock will be allocated and basic
* initialisation will be performed (s_type, s_fs_info and s_id will be set and
* the set() callback will be invoked), the superblock will be published and it
* will be returned in a partially constructed state with SB_BORN and SB_ACTIVE
* as yet unset.
*/
struct super_block *sget_fc(struct fs_context *fc,
int (*test)(struct super_block *, struct fs_context *),
int (*set)(struct super_block *, struct fs_context *))
{
struct super_block *s = NULL;
struct super_block *old;
struct user_namespace *user_ns = fc->global ? &init_user_ns : fc->user_ns;
int err;
if (!(fc->sb_flags & SB_KERNMOUNT) &&
fc->purpose != FS_CONTEXT_FOR_SUBMOUNT) {
/* Don't allow mounting unless the caller has CAP_SYS_ADMIN
* over the namespace.
*/
if (!(fc->fs_type->fs_flags & FS_USERNS_MOUNT)) {
if (!capable(CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);
} else {
if (!ns_capable(fc->user_ns, CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);
}
}
retry:
spin_lock(&sb_lock);
if (test) {
hlist_for_each_entry(old, &fc->fs_type->fs_supers, s_instances) {
if (test(old, fc))
goto share_extant_sb;
}
}
if (!s) {
spin_unlock(&sb_lock);
s = alloc_super(fc->fs_type, fc->sb_flags, user_ns);
if (!s)
return ERR_PTR(-ENOMEM);
goto retry;
}
s->s_fs_info = fc->s_fs_info;
err = set(s, fc);
if (err) {
s->s_fs_info = NULL;
spin_unlock(&sb_lock);
destroy_unused_super(s);
return ERR_PTR(err);
}
fc->s_fs_info = NULL;
s->s_type = fc->fs_type;
strlcpy(s->s_id, s->s_type->name, sizeof(s->s_id));
list_add_tail(&s->s_list, &super_blocks);
hlist_add_head(&s->s_instances, &s->s_type->fs_supers);
spin_unlock(&sb_lock);
get_filesystem(s->s_type);
register_shrinker_prepared(&s->s_shrink);
return s;
share_extant_sb:
if (user_ns != old->s_user_ns) {
spin_unlock(&sb_lock);
destroy_unused_super(s);
return ERR_PTR(-EBUSY);
}
if (!grab_super(old))
goto retry;
destroy_unused_super(s);
return old;
}
EXPORT_SYMBOL(sget_fc);
/**
* sget_userns - find or create a superblock
* @type: filesystem type superblock should belong to
@ -835,28 +924,35 @@ struct super_block *user_get_super(dev_t dev)
}
/**
* do_remount_sb - asks filesystem to change mount options.
* @sb: superblock in question
* @sb_flags: revised superblock flags
* @data: the rest of options
* @force: whether or not to force the change
* reconfigure_super - asks filesystem to change superblock parameters
* @fc: The superblock and configuration
*
* Alters the mount options of a mounted file system.
* Alters the configuration parameters of a live superblock.
*/
int do_remount_sb(struct super_block *sb, int sb_flags, void *data, int force)
int reconfigure_super(struct fs_context *fc)
{
struct super_block *sb = fc->root->d_sb;
int retval;
int remount_ro;
bool remount_ro = false;
bool force = fc->sb_flags & SB_FORCE;
if (fc->sb_flags_mask & ~MS_RMT_MASK)
return -EINVAL;
if (sb->s_writers.frozen != SB_UNFROZEN)
return -EBUSY;
retval = security_sb_remount(sb, fc->security);
if (retval)
return retval;
if (fc->sb_flags_mask & SB_RDONLY) {
#ifdef CONFIG_BLOCK
if (!(sb_flags & SB_RDONLY) && bdev_read_only(sb->s_bdev))
return -EACCES;
if (!(fc->sb_flags & SB_RDONLY) && bdev_read_only(sb->s_bdev))
return -EACCES;
#endif
remount_ro = (sb_flags & SB_RDONLY) && !sb_rdonly(sb);
remount_ro = (fc->sb_flags & SB_RDONLY) && !sb_rdonly(sb);
}
if (remount_ro) {
if (!hlist_empty(&sb->s_pins)) {
@ -867,13 +963,14 @@ int do_remount_sb(struct super_block *sb, int sb_flags, void *data, int force)
return 0;
if (sb->s_writers.frozen != SB_UNFROZEN)
return -EBUSY;
remount_ro = (sb_flags & SB_RDONLY) && !sb_rdonly(sb);
remount_ro = !sb_rdonly(sb);
}
}
shrink_dcache_sb(sb);
/* If we are remounting RDONLY and current sb is read/write,
make sure there are no rw files opened */
/* If we are reconfiguring to RDONLY and current sb is read/write,
* make sure there are no files open for writing.
*/
if (remount_ro) {
if (force) {
sb->s_readonly_remount = 1;
@ -885,8 +982,8 @@ int do_remount_sb(struct super_block *sb, int sb_flags, void *data, int force)
}
}
if (sb->s_op->remount_fs) {
retval = sb->s_op->remount_fs(sb, &sb_flags, data);
if (fc->ops->reconfigure) {
retval = fc->ops->reconfigure(fc);
if (retval) {
if (!force)
goto cancel_readonly;
@ -895,7 +992,9 @@ int do_remount_sb(struct super_block *sb, int sb_flags, void *data, int force)
sb->s_type->name, retval);
}
}
sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (sb_flags & MS_RMT_MASK);
WRITE_ONCE(sb->s_flags, ((sb->s_flags & ~fc->sb_flags_mask) |
(fc->sb_flags & fc->sb_flags_mask)));
/* Needs to be ordered wrt mnt_is_readonly() */
smp_wmb();
sb->s_readonly_remount = 0;
@ -922,10 +1021,15 @@ static void do_emergency_remount_callback(struct super_block *sb)
down_write(&sb->s_umount);
if (sb->s_root && sb->s_bdev && (sb->s_flags & SB_BORN) &&
!sb_rdonly(sb)) {
/*
* What lock protects sb->s_flags??
*/
do_remount_sb(sb, SB_RDONLY, NULL, 1);
struct fs_context *fc;
fc = fs_context_for_reconfigure(sb->s_root,
SB_RDONLY | SB_FORCE, SB_RDONLY);
if (!IS_ERR(fc)) {
if (parse_monolithic_mount_data(fc, NULL) == 0)
(void)reconfigure_super(fc);
put_fs_context(fc);
}
}
up_write(&sb->s_umount);
}
@ -1087,6 +1191,89 @@ struct dentry *mount_ns(struct file_system_type *fs_type,
EXPORT_SYMBOL(mount_ns);
int set_anon_super_fc(struct super_block *sb, struct fs_context *fc)
{
return set_anon_super(sb, NULL);
}
EXPORT_SYMBOL(set_anon_super_fc);
static int test_keyed_super(struct super_block *sb, struct fs_context *fc)
{
return sb->s_fs_info == fc->s_fs_info;
}
static int test_single_super(struct super_block *s, struct fs_context *fc)
{
return 1;
}
/**
* vfs_get_super - Get a superblock with a search key set in s_fs_info.
* @fc: The filesystem context holding the parameters
* @keying: How to distinguish superblocks
* @fill_super: Helper to initialise a new superblock
*
* Search for a superblock and create a new one if not found. The search
* criterion is controlled by @keying. If the search fails, a new superblock
* is created and @fill_super() is called to initialise it.
*
* @keying can take one of a number of values:
*
* (1) vfs_get_single_super - Only one superblock of this type may exist on the
* system. This is typically used for special system filesystems.
*
* (2) vfs_get_keyed_super - Multiple superblocks may exist, but they must have
* distinct keys (where the key is in s_fs_info). Searching for the same
* key again will turn up the superblock for that key.
*
* (3) vfs_get_independent_super - Multiple superblocks may exist and are
* unkeyed. Each call will get a new superblock.
*
* A permissions check is made by sget_fc() unless we're getting a superblock
* for a kernel-internal mount or a submount.
*/
int vfs_get_super(struct fs_context *fc,
enum vfs_get_super_keying keying,
int (*fill_super)(struct super_block *sb,
struct fs_context *fc))
{
int (*test)(struct super_block *, struct fs_context *);
struct super_block *sb;
switch (keying) {
case vfs_get_single_super:
test = test_single_super;
break;
case vfs_get_keyed_super:
test = test_keyed_super;
break;
case vfs_get_independent_super:
test = NULL;
break;
default:
BUG();
}
sb = sget_fc(fc, test, set_anon_super_fc);
if (IS_ERR(sb))
return PTR_ERR(sb);
if (!sb->s_root) {
int err = fill_super(sb, fc);
if (err) {
deactivate_locked_super(sb);
return err;
}
sb->s_flags |= SB_ACTIVE;
}
BUG_ON(fc->root);
fc->root = dget(sb->s_root);
return 0;
}
EXPORT_SYMBOL(vfs_get_super);
#ifdef CONFIG_BLOCK
static int set_bdev_super(struct super_block *s, void *data)
{
@ -1212,6 +1399,31 @@ struct dentry *mount_nodev(struct file_system_type *fs_type,
}
EXPORT_SYMBOL(mount_nodev);
static int reconfigure_single(struct super_block *s,
int flags, void *data)
{
struct fs_context *fc;
int ret;
/* The caller really need to be passing fc down into mount_single(),
* then a chunk of this can be removed. [Bollocks -- AV]
* Better yet, reconfiguration shouldn't happen, but rather the second
* mount should be rejected if the parameters are not compatible.
*/
fc = fs_context_for_reconfigure(s->s_root, flags, MS_RMT_MASK);
if (IS_ERR(fc))
return PTR_ERR(fc);
ret = parse_monolithic_mount_data(fc, data);
if (ret < 0)
goto out;
ret = reconfigure_super(fc);
out:
put_fs_context(fc);
return ret;
}
static int compare_single(struct super_block *s, void *p)
{
return 1;
@ -1229,41 +1441,64 @@ struct dentry *mount_single(struct file_system_type *fs_type,
return ERR_CAST(s);
if (!s->s_root) {
error = fill_super(s, data, flags & SB_SILENT ? 1 : 0);
if (error) {
deactivate_locked_super(s);
return ERR_PTR(error);
}
s->s_flags |= SB_ACTIVE;
if (!error)
s->s_flags |= SB_ACTIVE;
} else {
do_remount_sb(s, flags, data, 0);
error = reconfigure_single(s, flags, data);
}
if (unlikely(error)) {
deactivate_locked_super(s);
return ERR_PTR(error);
}
return dget(s->s_root);
}
EXPORT_SYMBOL(mount_single);
struct dentry *
mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
/**
* vfs_get_tree - Get the mountable root
* @fc: The superblock configuration context.
*
* The filesystem is invoked to get or create a superblock which can then later
* be used for mounting. The filesystem places a pointer to the root to be
* used for mounting in @fc->root.
*/
int vfs_get_tree(struct fs_context *fc)
{
struct dentry *root;
struct super_block *sb;
int error = -ENOMEM;
void *sec_opts = NULL;
int error;
if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {
error = security_sb_eat_lsm_opts(data, &sec_opts);
if (error)
return ERR_PTR(error);
if (fc->fs_type->fs_flags & FS_REQUIRES_DEV && !fc->source) {
errorf(fc, "Filesystem requires source device");
return -ENOENT;
}
root = type->mount(type, flags, name, data);
if (IS_ERR(root)) {
error = PTR_ERR(root);
goto out_free_secdata;
if (fc->root)
return -EBUSY;
/* Get the mountable root in fc->root, with a ref on the root and a ref
* on the superblock.
*/
error = fc->ops->get_tree(fc);
if (error < 0)
return error;
if (!fc->root) {
pr_err("Filesystem %s get_tree() didn't set fc->root\n",
fc->fs_type->name);
/* We don't know what the locking state of the superblock is -
* if there is a superblock.
*/
BUG();
}
sb = root->d_sb;
BUG_ON(!sb);
sb = fc->root->d_sb;
WARN_ON(!sb->s_bdi);
if (fc->subtype && !sb->s_subtype) {
sb->s_subtype = fc->subtype;
fc->subtype = NULL;
}
/*
* Write barrier is for super_cache_count(). We place it before setting
* SB_BORN as the data dependency between the two functions is the
@ -1273,14 +1508,10 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
smp_wmb();
sb->s_flags |= SB_BORN;
error = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
if (error)
goto out_sb;
if (!(flags & (MS_KERNMOUNT|MS_SUBMOUNT))) {
error = security_sb_kern_mount(sb);
if (error)
goto out_sb;
error = security_sb_set_mnt_opts(sb, fc->security, 0, NULL);
if (unlikely(error)) {
fc_drop_locked(fc);
return error;
}
/*
@ -1290,18 +1521,11 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
* violate this rule.
*/
WARN((sb->s_maxbytes < 0), "%s set sb->s_maxbytes to "
"negative value (%lld)\n", type->name, sb->s_maxbytes);
"negative value (%lld)\n", fc->fs_type->name, sb->s_maxbytes);
up_write(&sb->s_umount);
security_free_mnt_opts(&sec_opts);
return root;
out_sb:
dput(root);
deactivate_locked_super(sb);
out_free_secdata:
security_free_mnt_opts(&sec_opts);
return ERR_PTR(error);
return 0;
}
EXPORT_SYMBOL(vfs_get_tree);
/*
* Setup private BDI for given superblock. It gets automatically cleaned up

73
fs/sysfs/mount.c
View File

@ -13,34 +13,69 @@
#include <linux/magic.h>
#include <linux/mount.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/user_namespace.h>
#include <linux/fs_context.h>
#include <net/net_namespace.h>
#include "sysfs.h"
static struct kernfs_root *sysfs_root;
struct kernfs_node *sysfs_root_kn;
static struct dentry *sysfs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
static int sysfs_get_tree(struct fs_context *fc)
{
struct dentry *root;
void *ns;
bool new_sb = false;
struct kernfs_fs_context *kfc = fc->fs_private;
int ret;
if (!(flags & SB_KERNMOUNT)) {
ret = kernfs_get_tree(fc);
if (ret)
return ret;
if (kfc->new_sb_created)
fc->root->d_sb->s_iflags |= SB_I_USERNS_VISIBLE;
return 0;
}
static void sysfs_fs_context_free(struct fs_context *fc)
{
struct kernfs_fs_context *kfc = fc->fs_private;
if (kfc->ns_tag)
kobj_ns_drop(KOBJ_NS_TYPE_NET, kfc->ns_tag);
kernfs_free_fs_context(fc);
kfree(kfc);
}
static const struct fs_context_operations sysfs_fs_context_ops = {
.free = sysfs_fs_context_free,
.get_tree = sysfs_get_tree,
};
static int sysfs_init_fs_context(struct fs_context *fc)
{
struct kernfs_fs_context *kfc;
struct net *netns;
if (!(fc->sb_flags & SB_KERNMOUNT)) {
if (!kobj_ns_current_may_mount(KOBJ_NS_TYPE_NET))
return ERR_PTR(-EPERM);
return -EPERM;
}
ns = kobj_ns_grab_current(KOBJ_NS_TYPE_NET);
root = kernfs_mount_ns(fs_type, flags, sysfs_root,
SYSFS_MAGIC, &new_sb, ns);
if (!new_sb)
kobj_ns_drop(KOBJ_NS_TYPE_NET, ns);
else if (!IS_ERR(root))
root->d_sb->s_iflags |= SB_I_USERNS_VISIBLE;
kfc = kzalloc(sizeof(struct kernfs_fs_context), GFP_KERNEL);
if (!kfc)
return -ENOMEM;
return root;
kfc->ns_tag = netns = kobj_ns_grab_current(KOBJ_NS_TYPE_NET);
kfc->root = sysfs_root;
kfc->magic = SYSFS_MAGIC;
fc->fs_private = kfc;
fc->ops = &sysfs_fs_context_ops;
if (fc->user_ns)
put_user_ns(fc->user_ns);
fc->user_ns = get_user_ns(netns->user_ns);
fc->global = true;
return 0;
}
static void sysfs_kill_sb(struct super_block *sb)
@ -52,10 +87,10 @@ static void sysfs_kill_sb(struct super_block *sb)
}
static struct file_system_type sysfs_fs_type = {
.name = "sysfs",
.mount = sysfs_mount,
.kill_sb = sysfs_kill_sb,
.fs_flags = FS_USERNS_MOUNT,
.name = "sysfs",
.init_fs_context = sysfs_init_fs_context,
.kill_sb = sysfs_kill_sb,
.fs_flags = FS_USERNS_MOUNT,
};
int __init sysfs_init(void)

1
include/linux/errno.h
View File

@ -18,6 +18,7 @@
#define ERESTART_RESTARTBLOCK 516 /* restart by calling sys_restart_syscall */
#define EPROBE_DEFER 517 /* Driver requests probe retry */
#define EOPENSTALE 518 /* open found a stale dentry */
#define ENOPARAM 519 /* Parameter not supported */
/* Defined for the NFSv3 protocol */
#define EBADHANDLE 521 /* Illegal NFS file handle */

14
include/linux/fs.h
View File

@ -64,6 +64,8 @@ struct workqueue_struct;
struct iov_iter;
struct fscrypt_info;
struct fscrypt_operations;
struct fs_context;
struct fs_parameter_description;
extern void __init inode_init(void);
extern void __init inode_init_early(void);
@ -1349,6 +1351,7 @@ extern int send_sigurg(struct fown_struct *fown);
/* These sb flags are internal to the kernel */
#define SB_SUBMOUNT (1<<26)
#define SB_FORCE (1<<27)
#define SB_NOSEC (1<<28)
#define SB_BORN (1<<29)
#define SB_ACTIVE (1<<30)
@ -1459,7 +1462,7 @@ struct super_block {
* Filesystem subtype. If non-empty the filesystem type field
* in /proc/mounts will be "type.subtype"
*/
char *s_subtype;
const char *s_subtype;
const struct dentry_operations *s_d_op; /* default d_op for dentries */
@ -2170,6 +2173,8 @@ struct file_system_type {
#define FS_HAS_SUBTYPE 4
#define FS_USERNS_MOUNT 8 /* Can be mounted by userns root */
#define FS_RENAME_DOES_D_MOVE 32768 /* FS will handle d_move() during rename() internally. */
int (*init_fs_context)(struct fs_context *);
const struct fs_parameter_description *parameters;
struct dentry *(*mount) (struct file_system_type *, int,
const char *, void *);
void (*kill_sb) (struct super_block *);
@ -2225,8 +2230,12 @@ void kill_litter_super(struct super_block *sb);
void deactivate_super(struct super_block *sb);
void deactivate_locked_super(struct super_block *sb);
int set_anon_super(struct super_block *s, void *data);
int set_anon_super_fc(struct super_block *s, struct fs_context *fc);
int get_anon_bdev(dev_t *);
void free_anon_bdev(dev_t);
struct super_block *sget_fc(struct fs_context *fc,
int (*test)(struct super_block *, struct fs_context *),
int (*set)(struct super_block *, struct fs_context *));
struct super_block *sget_userns(struct file_system_type *type,
int (*test)(struct super_block *,void *),
int (*set)(struct super_block *,void *),
@ -2269,8 +2278,7 @@ mount_pseudo(struct file_system_type *fs_type, char *name,
extern int register_filesystem(struct file_system_type *);
extern int unregister_filesystem(struct file_system_type *);
extern struct vfsmount *kern_mount_data(struct file_system_type *, void *data);
#define kern_mount(type) kern_mount_data(type, NULL)
extern struct vfsmount *kern_mount(struct file_system_type *);
extern void kern_unmount(struct vfsmount *mnt);
extern int may_umount_tree(struct vfsmount *);
extern int may_umount(struct vfsmount *);

188
include/linux/fs_context.h Normal file
View File

@ -0,0 +1,188 @@
/* Filesystem superblock creation and reconfiguration context.
*
* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#ifndef _LINUX_FS_CONTEXT_H
#define _LINUX_FS_CONTEXT_H
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/security.h>
struct cred;
struct dentry;
struct file_operations;
struct file_system_type;
struct mnt_namespace;
struct net;
struct pid_namespace;
struct super_block;
struct user_namespace;
struct vfsmount;
struct path;
enum fs_context_purpose {
FS_CONTEXT_FOR_MOUNT, /* New superblock for explicit mount */
FS_CONTEXT_FOR_SUBMOUNT, /* New superblock for automatic submount */
FS_CONTEXT_FOR_RECONFIGURE, /* Superblock reconfiguration (remount) */
};
/*
* Type of parameter value.
*/
enum fs_value_type {
fs_value_is_undefined,
fs_value_is_flag, /* Value not given a value */
fs_value_is_string, /* Value is a string */
fs_value_is_blob, /* Value is a binary blob */
fs_value_is_filename, /* Value is a filename* + dirfd */
fs_value_is_filename_empty, /* Value is a filename* + dirfd + AT_EMPTY_PATH */
fs_value_is_file, /* Value is a file* */
};
/*
* Configuration parameter.
*/
struct fs_parameter {
const char *key; /* Parameter name */
enum fs_value_type type:8; /* The type of value here */
union {
char *string;
void *blob;
struct filename *name;
struct file *file;
};
size_t size;
int dirfd;
};
/*
* Filesystem context for holding the parameters used in the creation or
* reconfiguration of a superblock.
*
* Superblock creation fills in ->root whereas reconfiguration begins with this
* already set.
*
* See Documentation/filesystems/mounting.txt
*/
struct fs_context {
const struct fs_context_operations *ops;
struct file_system_type *fs_type;
void *fs_private; /* The filesystem's context */
struct dentry *root; /* The root and superblock */
struct user_namespace *user_ns; /* The user namespace for this mount */
struct net *net_ns; /* The network namespace for this mount */
const struct cred *cred; /* The mounter's credentials */
const char *source; /* The source name (eg. dev path) */
const char *subtype; /* The subtype to set on the superblock */
void *security; /* Linux S&M options */
void *s_fs_info; /* Proposed s_fs_info */
unsigned int sb_flags; /* Proposed superblock flags (SB_*) */
unsigned int sb_flags_mask; /* Superblock flags that were changed */
unsigned int lsm_flags; /* Information flags from the fs to the LSM */
enum fs_context_purpose purpose:8;
bool need_free:1; /* Need to call ops->free() */
bool global:1; /* Goes into &init_user_ns */
};
struct fs_context_operations {
void (*free)(struct fs_context *fc);
int (*dup)(struct fs_context *fc, struct fs_context *src_fc);
int (*parse_param)(struct fs_context *fc, struct fs_parameter *param);
int (*parse_monolithic)(struct fs_context *fc, void *data);
int (*get_tree)(struct fs_context *fc);
int (*reconfigure)(struct fs_context *fc);
};
/*
* fs_context manipulation functions.
*/
extern struct fs_context *fs_context_for_mount(struct file_system_type *fs_type,
unsigned int sb_flags);
extern struct fs_context *fs_context_for_reconfigure(struct dentry *dentry,
unsigned int sb_flags,
unsigned int sb_flags_mask);
extern struct fs_context *fs_context_for_submount(struct file_system_type *fs_type,
struct dentry *reference);
extern struct fs_context *vfs_dup_fs_context(struct fs_context *fc);
extern int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param);
extern int vfs_parse_fs_string(struct fs_context *fc, const char *key,
const char *value, size_t v_size);
extern int generic_parse_monolithic(struct fs_context *fc, void *data);
extern int vfs_get_tree(struct fs_context *fc);
extern void put_fs_context(struct fs_context *fc);
/*
* sget() wrapper to be called from the ->get_tree() op.
*/
enum vfs_get_super_keying {
vfs_get_single_super, /* Only one such superblock may exist */
vfs_get_keyed_super, /* Superblocks with different s_fs_info keys may exist */
vfs_get_independent_super, /* Multiple independent superblocks may exist */
};
extern int vfs_get_super(struct fs_context *fc,
enum vfs_get_super_keying keying,
int (*fill_super)(struct super_block *sb,
struct fs_context *fc));
extern const struct file_operations fscontext_fops;
#ifdef CONFIG_PRINTK
extern __attribute__((format(printf, 2, 3)))
void logfc(struct fs_context *fc, const char *fmt, ...);
#else
static inline __attribute__((format(printf, 2, 3)))
void logfc(struct fs_context *fc, const char *fmt, ...)
{
}
#endif
/**
* infof - Store supplementary informational message
* @fc: The context in which to log the informational message
* @fmt: The format string
*
* Store the supplementary informational message for the process if the process
* has enabled the facility.
*/
#define infof(fc, fmt, ...) ({ logfc(fc, "i "fmt, ## __VA_ARGS__); })
/**
* warnf - Store supplementary warning message
* @fc: The context in which to log the error message
* @fmt: The format string
*
* Store the supplementary warning message for the process if the process has
* enabled the facility.
*/
#define warnf(fc, fmt, ...) ({ logfc(fc, "w "fmt, ## __VA_ARGS__); })
/**
* errorf - Store supplementary error message
* @fc: The context in which to log the error message
* @fmt: The format string
*
* Store the supplementary error message for the process if the process has
* enabled the facility.
*/
#define errorf(fc, fmt, ...) ({ logfc(fc, "e "fmt, ## __VA_ARGS__); })
/**
* invalf - Store supplementary invalid argument error message
* @fc: The context in which to log the error message
* @fmt: The format string
*
* Store the supplementary error message for the process if the process has
* enabled the facility and return -EINVAL.
*/
#define invalf(fc, fmt, ...) ({ errorf(fc, fmt, ## __VA_ARGS__); -EINVAL; })
#endif /* _LINUX_FS_CONTEXT_H */

151
include/linux/fs_parser.h Normal file
View File

@ -0,0 +1,151 @@
/* Filesystem parameter description and parser
*
* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#ifndef _LINUX_FS_PARSER_H
#define _LINUX_FS_PARSER_H
#include <linux/fs_context.h>
struct path;
struct constant_table {
const char *name;
int value;
};
/*
* The type of parameter expected.
*/
enum fs_parameter_type {
__fs_param_wasnt_defined,
fs_param_is_flag,
fs_param_is_bool,
fs_param_is_u32,
fs_param_is_u32_octal,
fs_param_is_u32_hex,
fs_param_is_s32,
fs_param_is_u64,
fs_param_is_enum,
fs_param_is_string,
fs_param_is_blob,
fs_param_is_blockdev,
fs_param_is_path,
fs_param_is_fd,
nr__fs_parameter_type,
};
/*
* Specification of the type of value a parameter wants.
*
* Note that the fsparam_flag(), fsparam_string(), fsparam_u32(), ... macros
* should be used to generate elements of this type.
*/
struct fs_parameter_spec {
const char *name;
u8 opt; /* Option number (returned by fs_parse()) */
enum fs_parameter_type type:8; /* The desired parameter type */
unsigned short flags;
#define fs_param_v_optional 0x0001 /* The value is optional */
#define fs_param_neg_with_no 0x0002 /* "noxxx" is negative param */
#define fs_param_neg_with_empty 0x0004 /* "xxx=" is negative param */
#define fs_param_deprecated 0x0008 /* The param is deprecated */
};
struct fs_parameter_enum {
u8 opt; /* Option number (as fs_parameter_spec::opt) */
char name[14];
u8 value;
};
struct fs_parameter_description {
const char name[16]; /* Name for logging purposes */
const struct fs_parameter_spec *specs; /* List of param specifications */
const struct fs_parameter_enum *enums; /* Enum values */
};
/*
* Result of parse.
*/
struct fs_parse_result {
bool negated; /* T if param was "noxxx" */
bool has_value; /* T if value supplied to param */
union {
bool boolean; /* For spec_bool */
int int_32; /* For spec_s32/spec_enum */
unsigned int uint_32; /* For spec_u32{,_octal,_hex}/spec_enum */
u64 uint_64; /* For spec_u64 */
};
};
extern int fs_parse(struct fs_context *fc,
const struct fs_parameter_description *desc,
struct fs_parameter *value,
struct fs_parse_result *result);
extern int fs_lookup_param(struct fs_context *fc,
struct fs_parameter *param,
bool want_bdev,
struct path *_path);
extern int __lookup_constant(const struct constant_table tbl[], size_t tbl_size,
const char *name, int not_found);
#define lookup_constant(t, n, nf) __lookup_constant(t, ARRAY_SIZE(t), (n), (nf))
#ifdef CONFIG_VALIDATE_FS_PARSER
extern bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
int low, int high, int special);
extern bool fs_validate_description(const struct fs_parameter_description *desc);
#else
static inline bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
int low, int high, int special)
{ return true; }
static inline bool fs_validate_description(const struct fs_parameter_description *desc)
{ return true; }
#endif
/*
* Parameter type, name, index and flags element constructors. Use as:
*
* fsparam_xxxx("foo", Opt_foo)
*
* If existing helpers are not enough, direct use of __fsparam() would
* work, but any such case is probably a sign that new helper is needed.
* Helpers will remain stable; low-level implementation may change.
*/
#define __fsparam(TYPE, NAME, OPT, FLAGS) \
{ \
.name = NAME, \
.opt = OPT, \
.type = TYPE, \
.flags = FLAGS \
}
#define fsparam_flag(NAME, OPT) __fsparam(fs_param_is_flag, NAME, OPT, 0)
#define fsparam_flag_no(NAME, OPT) \
__fsparam(fs_param_is_flag, NAME, OPT, \
fs_param_neg_with_no)
#define fsparam_bool(NAME, OPT) __fsparam(fs_param_is_bool, NAME, OPT, 0)
#define fsparam_u32(NAME, OPT) __fsparam(fs_param_is_u32, NAME, OPT, 0)
#define fsparam_u32oct(NAME, OPT) \
__fsparam(fs_param_is_u32_octal, NAME, OPT, 0)
#define fsparam_u32hex(NAME, OPT) \
__fsparam(fs_param_is_u32_hex, NAME, OPT, 0)
#define fsparam_s32(NAME, OPT) __fsparam(fs_param_is_s32, NAME, OPT, 0)
#define fsparam_u64(NAME, OPT) __fsparam(fs_param_is_u64, NAME, OPT, 0)
#define fsparam_enum(NAME, OPT) __fsparam(fs_param_is_enum, NAME, OPT, 0)
#define fsparam_string(NAME, OPT) \
__fsparam(fs_param_is_string, NAME, OPT, 0)
#define fsparam_blob(NAME, OPT) __fsparam(fs_param_is_blob, NAME, OPT, 0)
#define fsparam_bdev(NAME, OPT) __fsparam(fs_param_is_blockdev, NAME, OPT, 0)
#define fsparam_path(NAME, OPT) __fsparam(fs_param_is_path, NAME, OPT, 0)
#define fsparam_fd(NAME, OPT) __fsparam(fs_param_is_fd, NAME, OPT, 0)
#endif /* _LINUX_FS_PARSER_H */

39
include/linux/kernfs.h
View File

@ -26,7 +26,9 @@ struct vm_area_struct;
struct super_block;
struct file_system_type;
struct poll_table_struct;
struct fs_context;
struct kernfs_fs_context;
struct kernfs_open_node;
struct kernfs_iattrs;
@ -168,7 +170,6 @@ struct kernfs_node {
* kernfs_node parameter.
*/
struct kernfs_syscall_ops {
int (*remount_fs)(struct kernfs_root *root, int *flags, char *data);
int (*show_options)(struct seq_file *sf, struct kernfs_root *root);
int (*mkdir)(struct kernfs_node *parent, const char *name,
@ -272,6 +273,18 @@ struct kernfs_ops {
#endif
};
/*
* The kernfs superblock creation/mount parameter context.
*/
struct kernfs_fs_context {
struct kernfs_root *root; /* Root of the hierarchy being mounted */
void *ns_tag; /* Namespace tag of the mount (or NULL) */
unsigned long magic; /* File system specific magic number */
/* The following are set/used by kernfs_mount() */
bool new_sb_created; /* Set to T if we allocated a new sb */
};
#ifdef CONFIG_KERNFS
static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn)
@ -359,11 +372,9 @@ __poll_t kernfs_generic_poll(struct kernfs_open_file *of,
void kernfs_notify(struct kernfs_node *kn);
const void *kernfs_super_ns(struct super_block *sb);
struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
struct kernfs_root *root, unsigned long magic,
bool *new_sb_created, const void *ns);
int kernfs_get_tree(struct fs_context *fc);
void kernfs_free_fs_context(struct fs_context *fc);
void kernfs_kill_sb(struct super_block *sb);
struct super_block *kernfs_pin_sb(struct kernfs_root *root, const void *ns);
void kernfs_init(void);
@ -465,11 +476,10 @@ static inline void kernfs_notify(struct kernfs_node *kn) { }
static inline const void *kernfs_super_ns(struct super_block *sb)
{ return NULL; }
static inline struct dentry *
kernfs_mount_ns(struct file_system_type *fs_type, int flags,
struct kernfs_root *root, unsigned long magic,
bool *new_sb_created, const void *ns)
{ return ERR_PTR(-ENOSYS); }
static inline int kernfs_get_tree(struct fs_context *fc)
{ return -ENOSYS; }
static inline void kernfs_free_fs_context(struct fs_context *fc) { }
static inline void kernfs_kill_sb(struct super_block *sb) { }
@ -552,13 +562,4 @@ static inline int kernfs_rename(struct kernfs_node *kn,
return kernfs_rename_ns(kn, new_parent, new_name, NULL);
}
static inline struct dentry *
kernfs_mount(struct file_system_type *fs_type, int flags,
struct kernfs_root *root, unsigned long magic,
bool *new_sb_created)
{
return kernfs_mount_ns(fs_type, flags, root,
magic, new_sb_created, NULL);
}
#endif /* __LINUX_KERNFS_H */

21
include/linux/lsm_hooks.h
View File

@ -76,6 +76,22 @@
* changes on the process such as clearing out non-inheritable signal
* state. This is called immediately after commit_creds().
*
* Security hooks for mount using fs_context.
* [See also Documentation/filesystems/mounting.txt]
*
* @fs_context_dup:
* Allocate and attach a security structure to sc->security. This pointer
* is initialised to NULL by the caller.
* @fc indicates the new filesystem context.
* @src_fc indicates the original filesystem context.
* @fs_context_parse_param:
* Userspace provided a parameter to configure a superblock. The LSM may
* reject it with an error and may use it for itself, in which case it
* should return 0; otherwise it should return -ENOPARAM to pass it on to
* the filesystem.
* @fc indicates the filesystem context.
* @param The parameter
*
* Security hooks for filesystem operations.
*
* @sb_alloc_security:
@ -1460,6 +1476,9 @@ union security_list_options {
void (*bprm_committing_creds)(struct linux_binprm *bprm);
void (*bprm_committed_creds)(struct linux_binprm *bprm);
int (*fs_context_dup)(struct fs_context *fc, struct fs_context *src_sc);
int (*fs_context_parse_param)(struct fs_context *fc, struct fs_parameter *param);
int (*sb_alloc_security)(struct super_block *sb);
void (*sb_free_security)(struct super_block *sb);
void (*sb_free_mnt_opts)(void *mnt_opts);
@ -1800,6 +1819,8 @@ struct security_hook_heads {
struct hlist_head bprm_check_security;
struct hlist_head bprm_committing_creds;
struct hlist_head bprm_committed_creds;
struct hlist_head fs_context_dup;
struct hlist_head fs_context_parse_param;
struct hlist_head sb_alloc_security;
struct hlist_head sb_free_security;
struct hlist_head sb_free_mnt_opts;

3
include/linux/mount.h
View File

@ -21,6 +21,7 @@ struct super_block;
struct vfsmount;
struct dentry;
struct mnt_namespace;
struct fs_context;
#define MNT_NOSUID 0x01
#define MNT_NODEV 0x02
@ -88,6 +89,8 @@ struct path;
extern struct vfsmount *clone_private_mount(const struct path *path);
struct file_system_type;
extern struct vfsmount *fc_mount(struct fs_context *fc);
extern struct vfsmount *vfs_create_mount(struct fs_context *fc);
extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
int flags, const char *name,
void *data);

18
include/linux/security.h
View File

@ -53,6 +53,9 @@ struct msg_msg;
struct xattr;
struct xfrm_sec_ctx;
struct mm_struct;
struct fs_context;
struct fs_parameter;
enum fs_value_type;
/* Default (no) options for the capable function */
#define CAP_OPT_NONE 0x0
@ -61,7 +64,7 @@ struct mm_struct;
/* If capable is being called by a setid function */
#define CAP_OPT_INSETID BIT(2)
/* LSM Agnostic defines for sb_set_mnt_opts */
/* LSM Agnostic defines for fs_context::lsm_flags */
#define SECURITY_LSM_NATIVE_LABELS 1
struct ctl_table;
@ -223,6 +226,8 @@ int security_bprm_set_creds(struct linux_binprm *bprm);
int security_bprm_check(struct linux_binprm *bprm);
void security_bprm_committing_creds(struct linux_binprm *bprm);
void security_bprm_committed_creds(struct linux_binprm *bprm);
int security_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc);
int security_fs_context_parse_param(struct fs_context *fc, struct fs_parameter *param);
int security_sb_alloc(struct super_block *sb);
void security_sb_free(struct super_block *sb);
void security_free_mnt_opts(void **mnt_opts);
@ -519,6 +524,17 @@ static inline void security_bprm_committed_creds(struct linux_binprm *bprm)
{
}
static inline int security_fs_context_dup(struct fs_context *fc,
struct fs_context *src_fc)
{
return 0;
}
static inline int security_fs_context_parse_param(struct fs_context *fc,
struct fs_parameter *param)
{
return -ENOPARAM;
}
static inline int security_sb_alloc(struct super_block *sb)
{
return 0;

94
ipc/mqueue.c
View File

@ -18,6 +18,7 @@
#include <linux/pagemap.h>
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/fs_context.h>
#include <linux/namei.h>
#include <linux/sysctl.h>
#include <linux/poll.h>
@ -42,6 +43,10 @@
#include <net/sock.h>
#include "util.h"
struct mqueue_fs_context {
struct ipc_namespace *ipc_ns;
};
#define MQUEUE_MAGIC 0x19800202
#define DIRENT_SIZE 20
#define FILENT_SIZE 80
@ -87,9 +92,11 @@ struct mqueue_inode_info {
unsigned long qsize; /* size of queue in memory (sum of all msgs) */
};
static struct file_system_type mqueue_fs_type;
static const struct inode_operations mqueue_dir_inode_operations;
static const struct file_operations mqueue_file_operations;
static const struct super_operations mqueue_super_ops;
static const struct fs_context_operations mqueue_fs_context_ops;
static void remove_notification(struct mqueue_inode_info *info);
static struct kmem_cache *mqueue_inode_cachep;
@ -322,7 +329,7 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
return ERR_PTR(ret);
}
static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
static int mqueue_fill_super(struct super_block *sb, struct fs_context *fc)
{
struct inode *inode;
struct ipc_namespace *ns = sb->s_fs_info;
@ -343,18 +350,56 @@ static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
return 0;
}
static struct dentry *mqueue_mount(struct file_system_type *fs_type,
int flags, const char *dev_name,
void *data)
static int mqueue_get_tree(struct fs_context *fc)
{
struct ipc_namespace *ns;
if (flags & SB_KERNMOUNT) {
ns = data;
data = NULL;
} else {
ns = current->nsproxy->ipc_ns;
}
return mount_ns(fs_type, flags, data, ns, ns->user_ns, mqueue_fill_super);
struct mqueue_fs_context *ctx = fc->fs_private;
put_user_ns(fc->user_ns);
fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns);
fc->s_fs_info = ctx->ipc_ns;
return vfs_get_super(fc, vfs_get_keyed_super, mqueue_fill_super);
}
static void mqueue_fs_context_free(struct fs_context *fc)
{
struct mqueue_fs_context *ctx = fc->fs_private;
if (ctx->ipc_ns)
put_ipc_ns(ctx->ipc_ns);
kfree(ctx);
}
static int mqueue_init_fs_context(struct fs_context *fc)
{
struct mqueue_fs_context *ctx;
ctx = kzalloc(sizeof(struct mqueue_fs_context), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns);
fc->fs_private = ctx;
fc->ops = &mqueue_fs_context_ops;
return 0;
}
static struct vfsmount *mq_create_mount(struct ipc_namespace *ns)
{
struct mqueue_fs_context *ctx;
struct fs_context *fc;
struct vfsmount *mnt;
fc = fs_context_for_mount(&mqueue_fs_type, SB_KERNMOUNT);
if (IS_ERR(fc))
return ERR_CAST(fc);
ctx = fc->fs_private;
put_ipc_ns(ctx->ipc_ns);
ctx->ipc_ns = get_ipc_ns(ns);
mnt = fc_mount(fc);
put_fs_context(fc);
return mnt;
}
static void init_once(void *foo)
@ -1522,15 +1567,22 @@ static const struct super_operations mqueue_super_ops = {
.statfs = simple_statfs,
};
static const struct fs_context_operations mqueue_fs_context_ops = {
.free = mqueue_fs_context_free,
.get_tree = mqueue_get_tree,
};
static struct file_system_type mqueue_fs_type = {
.name = "mqueue",
.mount = mqueue_mount,
.kill_sb = kill_litter_super,
.fs_flags = FS_USERNS_MOUNT,
.name = "mqueue",
.init_fs_context = mqueue_init_fs_context,
.kill_sb = kill_litter_super,
.fs_flags = FS_USERNS_MOUNT,
};
int mq_init_ns(struct ipc_namespace *ns)
{
struct vfsmount *m;
ns->mq_queues_count = 0;
ns->mq_queues_max = DFLT_QUEUESMAX;
ns->mq_msg_max = DFLT_MSGMAX;
@ -1538,12 +1590,10 @@ int mq_init_ns(struct ipc_namespace *ns)
ns->mq_msg_default = DFLT_MSG;
ns->mq_msgsize_default = DFLT_MSGSIZE;
ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
if (IS_ERR(ns->mq_mnt)) {
int err = PTR_ERR(ns->mq_mnt);
ns->mq_mnt = NULL;
return err;
}
m = mq_create_mount(ns);
if (IS_ERR(m))
return PTR_ERR(m);
ns->mq_mnt = m;
return 0;
}

2
ipc/namespace.c
View File

@ -42,7 +42,7 @@ static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
goto fail;
err = -ENOMEM;
ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
ns = kzalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
if (ns == NULL)
goto fail_dec;

49
kernel/cgroup/cgroup-internal.h
View File

@ -7,6 +7,7 @@
#include <linux/workqueue.h>
#include <linux/list.h>
#include <linux/refcount.h>
#include <linux/fs_context.h>
#define TRACE_CGROUP_PATH_LEN 1024
extern spinlock_t trace_cgroup_path_lock;
@ -36,6 +37,31 @@ extern void __init enable_debug_cgroup(void);
} \
} while (0)
/*
* The cgroup filesystem superblock creation/mount context.
*/
struct cgroup_fs_context {
struct kernfs_fs_context kfc;
struct cgroup_root *root;
struct cgroup_namespace *ns;
unsigned int flags; /* CGRP_ROOT_* flags */
/* cgroup1 bits */
bool cpuset_clone_children;
bool none; /* User explicitly requested empty subsystem */
bool all_ss; /* Seen 'all' option */
u16 subsys_mask; /* Selected subsystems */
char *name; /* Hierarchy name */
char *release_agent; /* Path for release notifications */
};
static inline struct cgroup_fs_context *cgroup_fc2context(struct fs_context *fc)
{
struct kernfs_fs_context *kfc = fc->fs_private;
return container_of(kfc, struct cgroup_fs_context, kfc);
}
/*
* A cgroup can be associated with multiple css_sets as different tasks may
* belong to different cgroups on different hierarchies. In the other
@ -117,16 +143,6 @@ struct cgroup_mgctx {
#define DEFINE_CGROUP_MGCTX(name) \
struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name)
struct cgroup_sb_opts {
u16 subsys_mask;
unsigned int flags;
char *release_agent;
bool cpuset_clone_children;
char *name;
/* User explicitly requested empty subsystem */
bool none;
};
extern struct mutex cgroup_mutex;
extern spinlock_t css_set_lock;
extern struct cgroup_subsys *cgroup_subsys[];
@ -197,12 +213,10 @@ int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
struct cgroup_namespace *ns);
void cgroup_free_root(struct cgroup_root *root);
void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts);
void init_cgroup_root(struct cgroup_fs_context *ctx);
int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask);
int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags,
struct cgroup_root *root, unsigned long magic,
struct cgroup_namespace *ns);
int cgroup_do_get_tree(struct fs_context *fc);
int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp);
void cgroup_migrate_finish(struct cgroup_mgctx *mgctx);
@ -246,14 +260,15 @@ extern const struct proc_ns_operations cgroupns_operations;
*/
extern struct cftype cgroup1_base_files[];
extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops;
extern const struct fs_parameter_description cgroup1_fs_parameters;
int proc_cgroupstats_show(struct seq_file *m, void *v);
bool cgroup1_ssid_disabled(int ssid);
void cgroup1_pidlist_destroy_all(struct cgroup *cgrp);
void cgroup1_release_agent(struct work_struct *work);
void cgroup1_check_for_release(struct cgroup *cgrp);
struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags,
void *data, unsigned long magic,
struct cgroup_namespace *ns);
int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param);
int cgroup1_get_tree(struct fs_context *fc);
int cgroup1_reconfigure(struct fs_context *ctx);
#endif /* __CGROUP_INTERNAL_H */

400
kernel/cgroup/cgroup-v1.c
View File

@ -13,9 +13,12 @@
#include <linux/delayacct.h>
#include <linux/pid_namespace.h>
#include <linux/cgroupstats.h>
#include <linux/fs_parser.h>
#include <trace/events/cgroup.h>
#define cg_invalf(fc, fmt, ...) invalf(fc, fmt, ## __VA_ARGS__)
/*
* pidlists linger the following amount before being destroyed. The goal
* is avoiding frequent destruction in the middle of consecutive read calls
@ -906,172 +909,195 @@ static int cgroup1_show_options(struct seq_file *seq, struct kernfs_root *kf_roo
return 0;
}
static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
enum cgroup1_param {
Opt_all,
Opt_clone_children,
Opt_cpuset_v2_mode,
Opt_name,
Opt_none,
Opt_noprefix,
Opt_release_agent,
Opt_xattr,
};
static const struct fs_parameter_spec cgroup1_param_specs[] = {
fsparam_flag ("all", Opt_all),
fsparam_flag ("clone_children", Opt_clone_children),
fsparam_flag ("cpuset_v2_mode", Opt_cpuset_v2_mode),
fsparam_string("name", Opt_name),
fsparam_flag ("none", Opt_none),
fsparam_flag ("noprefix", Opt_noprefix),
fsparam_string("release_agent", Opt_release_agent),
fsparam_flag ("xattr", Opt_xattr),
{}
};
const struct fs_parameter_description cgroup1_fs_parameters = {
.name = "cgroup1",
.specs = cgroup1_param_specs,
};
int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
char *token, *o = data;
bool all_ss = false, one_ss = false;
u16 mask = U16_MAX;
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
struct cgroup_subsys *ss;
struct fs_parse_result result;
int opt, i;
opt = fs_parse(fc, &cgroup1_fs_parameters, param, &result);
if (opt == -ENOPARAM) {
if (strcmp(param->key, "source") == 0) {
fc->source = param->string;
param->string = NULL;
return 0;
}
for_each_subsys(ss, i) {
if (strcmp(param->key, ss->legacy_name))
continue;
ctx->subsys_mask |= (1 << i);
return 0;
}
return cg_invalf(fc, "cgroup1: Unknown subsys name '%s'", param->key);
}
if (opt < 0)
return opt;
switch (opt) {
case Opt_none:
/* Explicitly have no subsystems */
ctx->none = true;
break;
case Opt_all:
ctx->all_ss = true;
break;
case Opt_noprefix:
ctx->flags |= CGRP_ROOT_NOPREFIX;
break;
case Opt_clone_children:
ctx->cpuset_clone_children = true;
break;
case Opt_cpuset_v2_mode:
ctx->flags |= CGRP_ROOT_CPUSET_V2_MODE;
break;
case Opt_xattr:
ctx->flags |= CGRP_ROOT_XATTR;
break;
case Opt_release_agent:
/* Specifying two release agents is forbidden */
if (ctx->release_agent)
return cg_invalf(fc, "cgroup1: release_agent respecified");
ctx->release_agent = param->string;
param->string = NULL;
break;
case Opt_name:
/* blocked by boot param? */
if (cgroup_no_v1_named)
return -ENOENT;
/* Can't specify an empty name */
if (!param->size)
return cg_invalf(fc, "cgroup1: Empty name");
if (param->size > MAX_CGROUP_ROOT_NAMELEN - 1)
return cg_invalf(fc, "cgroup1: Name too long");
/* Must match [\w.-]+ */
for (i = 0; i < param->size; i++) {
char c = param->string[i];
if (isalnum(c))
continue;
if ((c == '.') || (c == '-') || (c == '_'))
continue;
return cg_invalf(fc, "cgroup1: Invalid name");
}
/* Specifying two names is forbidden */
if (ctx->name)
return cg_invalf(fc, "cgroup1: name respecified");
ctx->name = param->string;
param->string = NULL;
break;
}
return 0;
}
static int check_cgroupfs_options(struct fs_context *fc)
{
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
u16 mask = U16_MAX;
u16 enabled = 0;
struct cgroup_subsys *ss;
int nr_opts = 0;
int i;
#ifdef CONFIG_CPUSETS
mask = ~((u16)1 << cpuset_cgrp_id);
#endif
for_each_subsys(ss, i)
if (cgroup_ssid_enabled(i) && !cgroup1_ssid_disabled(i))
enabled |= 1 << i;
memset(opts, 0, sizeof(*opts));
while ((token = strsep(&o, ",")) != NULL) {
nr_opts++;
if (!*token)
return -EINVAL;
if (!strcmp(token, "none")) {
/* Explicitly have no subsystems */
opts->none = true;
continue;
}
if (!strcmp(token, "all")) {
/* Mutually exclusive option 'all' + subsystem name */
if (one_ss)
return -EINVAL;
all_ss = true;
continue;
}
if (!strcmp(token, "noprefix")) {
opts->flags |= CGRP_ROOT_NOPREFIX;
continue;
}
if (!strcmp(token, "clone_children")) {
opts->cpuset_clone_children = true;
continue;
}
if (!strcmp(token, "cpuset_v2_mode")) {
opts->flags |= CGRP_ROOT_CPUSET_V2_MODE;
continue;
}
if (!strcmp(token, "xattr")) {
opts->flags |= CGRP_ROOT_XATTR;
continue;
}
if (!strncmp(token, "release_agent=", 14)) {
/* Specifying two release agents is forbidden */
if (opts->release_agent)
return -EINVAL;
opts->release_agent =
kstrndup(token + 14, PATH_MAX - 1, GFP_KERNEL);
if (!opts->release_agent)
return -ENOMEM;
continue;
}
if (!strncmp(token, "name=", 5)) {
const char *name = token + 5;
/* blocked by boot param? */
if (cgroup_no_v1_named)
return -ENOENT;
/* Can't specify an empty name */
if (!strlen(name))
return -EINVAL;
/* Must match [\w.-]+ */
for (i = 0; i < strlen(name); i++) {
char c = name[i];
if (isalnum(c))
continue;
if ((c == '.') || (c == '-') || (c == '_'))
continue;
return -EINVAL;
}
/* Specifying two names is forbidden */
if (opts->name)
return -EINVAL;
opts->name = kstrndup(name,
MAX_CGROUP_ROOT_NAMELEN - 1,
GFP_KERNEL);
if (!opts->name)
return -ENOMEM;
continue;
}
for_each_subsys(ss, i) {
if (strcmp(token, ss->legacy_name))
continue;
if (!cgroup_ssid_enabled(i))
continue;
if (cgroup1_ssid_disabled(i))
continue;
/* Mutually exclusive option 'all' + subsystem name */
if (all_ss)
return -EINVAL;
opts->subsys_mask |= (1 << i);
one_ss = true;
break;
}
if (i == CGROUP_SUBSYS_COUNT)
return -ENOENT;
}
ctx->subsys_mask &= enabled;
/*
* If the 'all' option was specified select all the subsystems,
* otherwise if 'none', 'name=' and a subsystem name options were
* not specified, let's default to 'all'
* In absense of 'none', 'name=' or subsystem name options,
* let's default to 'all'.
*/
if (all_ss || (!one_ss && !opts->none && !opts->name))
for_each_subsys(ss, i)
if (cgroup_ssid_enabled(i) && !cgroup1_ssid_disabled(i))
opts->subsys_mask |= (1 << i);
if (!ctx->subsys_mask && !ctx->none && !ctx->name)
ctx->all_ss = true;
if (ctx->all_ss) {
/* Mutually exclusive option 'all' + subsystem name */
if (ctx->subsys_mask)
return cg_invalf(fc, "cgroup1: subsys name conflicts with all");
/* 'all' => select all the subsystems */
ctx->subsys_mask = enabled;
}
/*
* We either have to specify by name or by subsystems. (So all
* empty hierarchies must have a name).
*/
if (!opts->subsys_mask && !opts->name)
return -EINVAL;
if (!ctx->subsys_mask && !ctx->name)
return cg_invalf(fc, "cgroup1: Need name or subsystem set");
/*
* Option noprefix was introduced just for backward compatibility
* with the old cpuset, so we allow noprefix only if mounting just
* the cpuset subsystem.
*/
if ((opts->flags & CGRP_ROOT_NOPREFIX) && (opts->subsys_mask & mask))
return -EINVAL;
if ((ctx->flags & CGRP_ROOT_NOPREFIX) && (ctx->subsys_mask & mask))
return cg_invalf(fc, "cgroup1: noprefix used incorrectly");
/* Can't specify "none" and some subsystems */
if (opts->subsys_mask && opts->none)
return -EINVAL;
if (ctx->subsys_mask && ctx->none)
return cg_invalf(fc, "cgroup1: none used incorrectly");
return 0;
}
static int cgroup1_remount(struct kernfs_root *kf_root, int *flags, char *data)
int cgroup1_reconfigure(struct fs_context *fc)
{
int ret = 0;
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
struct kernfs_root *kf_root = kernfs_root_from_sb(fc->root->d_sb);
struct cgroup_root *root = cgroup_root_from_kf(kf_root);
struct cgroup_sb_opts opts;
int ret = 0;
u16 added_mask, removed_mask;
cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
/* See what subsystems are wanted */
ret = parse_cgroupfs_options(data, &opts);
ret = check_cgroupfs_options(fc);
if (ret)
goto out_unlock;
if (opts.subsys_mask != root->subsys_mask || opts.release_agent)
if (ctx->subsys_mask != root->subsys_mask || ctx->release_agent)
pr_warn("option changes via remount are deprecated (pid=%d comm=%s)\n",
task_tgid_nr(current), current->comm);
added_mask = opts.subsys_mask & ~root->subsys_mask;
removed_mask = root->subsys_mask & ~opts.subsys_mask;
added_mask = ctx->subsys_mask & ~root->subsys_mask;
removed_mask = root->subsys_mask & ~ctx->subsys_mask;
/* Don't allow flags or name to change at remount */
if ((opts.flags ^ root->flags) ||
(opts.name && strcmp(opts.name, root->name))) {
pr_err("option or name mismatch, new: 0x%x \"%s\", old: 0x%x \"%s\"\n",
opts.flags, opts.name ?: "", root->flags, root->name);
if ((ctx->flags ^ root->flags) ||
(ctx->name && strcmp(ctx->name, root->name))) {
cg_invalf(fc, "option or name mismatch, new: 0x%x \"%s\", old: 0x%x \"%s\"",
ctx->flags, ctx->name ?: "", root->flags, root->name);
ret = -EINVAL;
goto out_unlock;
}
@ -1088,17 +1114,15 @@ static int cgroup1_remount(struct kernfs_root *kf_root, int *flags, char *data)
WARN_ON(rebind_subsystems(&cgrp_dfl_root, removed_mask));
if (opts.release_agent) {
if (ctx->release_agent) {
spin_lock(&release_agent_path_lock);
strcpy(root->release_agent_path, opts.release_agent);
strcpy(root->release_agent_path, ctx->release_agent);
spin_unlock(&release_agent_path_lock);
}
trace_cgroup_remount(root);
out_unlock:
kfree(opts.release_agent);
kfree(opts.name);
mutex_unlock(&cgroup_mutex);
return ret;
}
@ -1106,28 +1130,30 @@ static int cgroup1_remount(struct kernfs_root *kf_root, int *flags, char *data)
struct kernfs_syscall_ops cgroup1_kf_syscall_ops = {
.rename = cgroup1_rename,
.show_options = cgroup1_show_options,
.remount_fs = cgroup1_remount,
.mkdir = cgroup_mkdir,
.rmdir = cgroup_rmdir,
.show_path = cgroup_show_path,
};
struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags,
void *data, unsigned long magic,
struct cgroup_namespace *ns)
/*
* The guts of cgroup1 mount - find or create cgroup_root to use.
* Called with cgroup_mutex held; returns 0 on success, -E... on
* error and positive - in case when the candidate is busy dying.
* On success it stashes a reference to cgroup_root into given
* cgroup_fs_context; that reference is *NOT* counting towards the
* cgroup_root refcount.
*/
static int cgroup1_root_to_use(struct fs_context *fc)
{
struct cgroup_sb_opts opts;
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
struct cgroup_root *root;
struct cgroup_subsys *ss;
struct dentry *dentry;
int i, ret;
cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
/* First find the desired set of subsystems */
ret = parse_cgroupfs_options(data, &opts);
ret = check_cgroupfs_options(fc);
if (ret)
goto out_unlock;
return ret;
/*
* Destruction of cgroup root is asynchronous, so subsystems may
@ -1137,16 +1163,12 @@ struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags,
* starting. Testing ref liveliness is good enough.
*/
for_each_subsys(ss, i) {
if (!(opts.subsys_mask & (1 << i)) ||
if (!(ctx->subsys_mask & (1 << i)) ||
ss->root == &cgrp_dfl_root)
continue;
if (!percpu_ref_tryget_live(&ss->root->cgrp.self.refcnt)) {
mutex_unlock(&cgroup_mutex);
msleep(10);
ret = restart_syscall();
goto out_free;
}
if (!percpu_ref_tryget_live(&ss->root->cgrp.self.refcnt))
return 1; /* restart */
cgroup_put(&ss->root->cgrp);
}
@ -1161,8 +1183,8 @@ struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags,
* name matches but sybsys_mask doesn't, we should fail.
* Remember whether name matched.
*/
if (opts.name) {
if (strcmp(opts.name, root->name))
if (ctx->name) {
if (strcmp(ctx->name, root->name))
continue;
name_match = true;
}
@ -1171,19 +1193,18 @@ struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags,
* If we asked for subsystems (or explicitly for no
* subsystems) then they must match.
*/
if ((opts.subsys_mask || opts.none) &&
(opts.subsys_mask != root->subsys_mask)) {
if ((ctx->subsys_mask || ctx->none) &&
(ctx->subsys_mask != root->subsys_mask)) {
if (!name_match)
continue;
ret = -EBUSY;
goto out_unlock;
return -EBUSY;
}
if (root->flags ^ opts.flags)
if (root->flags ^ ctx->flags)
pr_warn("new mount options do not match the existing superblock, will be ignored\n");
ret = 0;
goto out_unlock;
ctx->root = root;
return 0;
}
/*
@ -1191,55 +1212,58 @@ struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags,
* specification is allowed for already existing hierarchies but we
* can't create new one without subsys specification.
*/
if (!opts.subsys_mask && !opts.none) {
ret = -EINVAL;
goto out_unlock;
}
if (!ctx->subsys_mask && !ctx->none)
return cg_invalf(fc, "cgroup1: No subsys list or none specified");
/* Hierarchies may only be created in the initial cgroup namespace. */
if (ns != &init_cgroup_ns) {
ret = -EPERM;
goto out_unlock;
}
if (ctx->ns != &init_cgroup_ns)
return -EPERM;
root = kzalloc(sizeof(*root), GFP_KERNEL);
if (!root) {
ret = -ENOMEM;
goto out_unlock;
}
if (!root)
return -ENOMEM;
init_cgroup_root(root, &opts);
ctx->root = root;
init_cgroup_root(ctx);
ret = cgroup_setup_root(root, opts.subsys_mask);
ret = cgroup_setup_root(root, ctx->subsys_mask);
if (ret)
cgroup_free_root(root);
return ret;
}
int cgroup1_get_tree(struct fs_context *fc)
{
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
int ret;
/* Check if the caller has permission to mount. */
if (!ns_capable(ctx->ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
ret = cgroup1_root_to_use(fc);
if (!ret && !percpu_ref_tryget_live(&ctx->root->cgrp.self.refcnt))
ret = 1; /* restart */
out_unlock:
if (!ret && !percpu_ref_tryget_live(&root->cgrp.self.refcnt)) {
mutex_unlock(&cgroup_mutex);
msleep(10);
ret = restart_syscall();
goto out_free;
}
mutex_unlock(&cgroup_mutex);
out_free:
kfree(opts.release_agent);
kfree(opts.name);
if (ret)
return ERR_PTR(ret);
if (!ret)
ret = cgroup_do_get_tree(fc);
dentry = cgroup_do_mount(&cgroup_fs_type, flags, root,
CGROUP_SUPER_MAGIC, ns);
if (!IS_ERR(dentry) && percpu_ref_is_dying(&root->cgrp.self.refcnt)) {
struct super_block *sb = dentry->d_sb;
dput(dentry);
if (!ret && percpu_ref_is_dying(&ctx->root->cgrp.self.refcnt)) {
struct super_block *sb = fc->root->d_sb;
dput(fc->root);
deactivate_locked_super(sb);
msleep(10);
dentry = ERR_PTR(restart_syscall());
ret = 1;
}
return dentry;
if (unlikely(ret > 0)) {
msleep(10);
return restart_syscall();
}
return ret;
}
static int __init cgroup1_wq_init(void)

223
kernel/cgroup/cgroup.c
View File

@ -54,6 +54,7 @@
#include <linux/proc_ns.h>
#include <linux/nsproxy.h>
#include <linux/file.h>
#include <linux/fs_parser.h>
#include <linux/sched/cputime.h>
#include <linux/psi.h>
#include <net/sock.h>
@ -1772,26 +1773,37 @@ int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
return len;
}
static int parse_cgroup_root_flags(char *data, unsigned int *root_flags)
enum cgroup2_param {
Opt_nsdelegate,
nr__cgroup2_params
};
static const struct fs_parameter_spec cgroup2_param_specs[] = {
fsparam_flag ("nsdelegate", Opt_nsdelegate),
{}
};
static const struct fs_parameter_description cgroup2_fs_parameters = {
.name = "cgroup2",
.specs = cgroup2_param_specs,
};
static int cgroup2_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
char *token;
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
struct fs_parse_result result;
int opt;
*root_flags = 0;
opt = fs_parse(fc, &cgroup2_fs_parameters, param, &result);
if (opt < 0)
return opt;
if (!data || *data == '\0')
switch (opt) {
case Opt_nsdelegate:
ctx->flags |= CGRP_ROOT_NS_DELEGATE;
return 0;
while ((token = strsep(&data, ",")) != NULL) {
if (!strcmp(token, "nsdelegate")) {
*root_flags |= CGRP_ROOT_NS_DELEGATE;
continue;
}
pr_err("cgroup2: unknown option \"%s\"\n", token);
return -EINVAL;
}
return 0;
return -EINVAL;
}
static void apply_cgroup_root_flags(unsigned int root_flags)
@ -1811,16 +1823,11 @@ static int cgroup_show_options(struct seq_file *seq, struct kernfs_root *kf_root
return 0;
}
static int cgroup_remount(struct kernfs_root *kf_root, int *flags, char *data)
static int cgroup_reconfigure(struct fs_context *fc)
{
unsigned int root_flags;
int ret;
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
ret = parse_cgroup_root_flags(data, &root_flags);
if (ret)
return ret;
apply_cgroup_root_flags(root_flags);
apply_cgroup_root_flags(ctx->flags);
return 0;
}
@ -1908,8 +1915,9 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp)
INIT_WORK(&cgrp->release_agent_work, cgroup1_release_agent);
}
void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts)
void init_cgroup_root(struct cgroup_fs_context *ctx)
{
struct cgroup_root *root = ctx->root;
struct cgroup *cgrp = &root->cgrp;
INIT_LIST_HEAD(&root->root_list);
@ -1918,12 +1926,12 @@ void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts)
init_cgroup_housekeeping(cgrp);
idr_init(&root->cgroup_idr);
root->flags = opts->flags;
if (opts->release_agent)
strscpy(root->release_agent_path, opts->release_agent, PATH_MAX);
if (opts->name)
strscpy(root->name, opts->name, MAX_CGROUP_ROOT_NAMELEN);
if (opts->cpuset_clone_children)
root->flags = ctx->flags;
if (ctx->release_agent)
strscpy(root->release_agent_path, ctx->release_agent, PATH_MAX);
if (ctx->name)
strscpy(root->name, ctx->name, MAX_CGROUP_ROOT_NAMELEN);
if (ctx->cpuset_clone_children)
set_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags);
}
@ -2028,60 +2036,104 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
return ret;
}
struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags,
struct cgroup_root *root, unsigned long magic,
struct cgroup_namespace *ns)
int cgroup_do_get_tree(struct fs_context *fc)
{
struct dentry *dentry;
bool new_sb = false;
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
int ret;
dentry = kernfs_mount(fs_type, flags, root->kf_root, magic, &new_sb);
ctx->kfc.root = ctx->root->kf_root;
if (fc->fs_type == &cgroup2_fs_type)
ctx->kfc.magic = CGROUP2_SUPER_MAGIC;
else
ctx->kfc.magic = CGROUP_SUPER_MAGIC;
ret = kernfs_get_tree(fc);
/*
* In non-init cgroup namespace, instead of root cgroup's dentry,
* we return the dentry corresponding to the cgroupns->root_cgrp.
*/
if (!IS_ERR(dentry) && ns != &init_cgroup_ns) {
if (!ret && ctx->ns != &init_cgroup_ns) {
struct dentry *nsdentry;
struct super_block *sb = dentry->d_sb;
struct super_block *sb = fc->root->d_sb;
struct cgroup *cgrp;
mutex_lock(&cgroup_mutex);
spin_lock_irq(&css_set_lock);
cgrp = cset_cgroup_from_root(ns->root_cset, root);
cgrp = cset_cgroup_from_root(ctx->ns->root_cset, ctx->root);
spin_unlock_irq(&css_set_lock);
mutex_unlock(&cgroup_mutex);
nsdentry = kernfs_node_dentry(cgrp->kn, sb);
dput(dentry);
if (IS_ERR(nsdentry))
dput(fc->root);
fc->root = nsdentry;
if (IS_ERR(nsdentry)) {
ret = PTR_ERR(nsdentry);
deactivate_locked_super(sb);
dentry = nsdentry;
}
}
if (!new_sb)
cgroup_put(&root->cgrp);
if (!ctx->kfc.new_sb_created)
cgroup_put(&ctx->root->cgrp);
return dentry;
return ret;
}
static struct dentry *cgroup_mount(struct file_system_type *fs_type,
int flags, const char *unused_dev_name,
void *data)
/*
* Destroy a cgroup filesystem context.
*/
static void cgroup_fs_context_free(struct fs_context *fc)
{
struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;
struct dentry *dentry;
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
kfree(ctx->name);
kfree(ctx->release_agent);
put_cgroup_ns(ctx->ns);
kernfs_free_fs_context(fc);
kfree(ctx);
}
static int cgroup_get_tree(struct fs_context *fc)
{
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
int ret;
get_cgroup_ns(ns);
cgrp_dfl_visible = true;
cgroup_get_live(&cgrp_dfl_root.cgrp);
ctx->root = &cgrp_dfl_root;
/* Check if the caller has permission to mount. */
if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) {
put_cgroup_ns(ns);
return ERR_PTR(-EPERM);
}
ret = cgroup_do_get_tree(fc);
if (!ret)
apply_cgroup_root_flags(ctx->flags);
return ret;
}
static const struct fs_context_operations cgroup_fs_context_ops = {
.free = cgroup_fs_context_free,
.parse_param = cgroup2_parse_param,
.get_tree = cgroup_get_tree,
.reconfigure = cgroup_reconfigure,
};
static const struct fs_context_operations cgroup1_fs_context_ops = {
.free = cgroup_fs_context_free,
.parse_param = cgroup1_parse_param,
.get_tree = cgroup1_get_tree,
.reconfigure = cgroup1_reconfigure,
};
/*
* Initialise the cgroup filesystem creation/reconfiguration context. Notably,
* we select the namespace we're going to use.
*/
static int cgroup_init_fs_context(struct fs_context *fc)
{
struct cgroup_fs_context *ctx;
ctx = kzalloc(sizeof(struct cgroup_fs_context), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
/*
* The first time anyone tries to mount a cgroup, enable the list
@ -2090,29 +2142,18 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
if (!use_task_css_set_links)
cgroup_enable_task_cg_lists();
if (fs_type == &cgroup2_fs_type) {
unsigned int root_flags;
ret = parse_cgroup_root_flags(data, &root_flags);
if (ret) {
put_cgroup_ns(ns);
return ERR_PTR(ret);
}
cgrp_dfl_visible = true;
cgroup_get_live(&cgrp_dfl_root.cgrp);
dentry = cgroup_do_mount(&cgroup2_fs_type, flags, &cgrp_dfl_root,
CGROUP2_SUPER_MAGIC, ns);
if (!IS_ERR(dentry))
apply_cgroup_root_flags(root_flags);
} else {
dentry = cgroup1_mount(&cgroup_fs_type, flags, data,
CGROUP_SUPER_MAGIC, ns);
}
put_cgroup_ns(ns);
return dentry;
ctx->ns = current->nsproxy->cgroup_ns;
get_cgroup_ns(ctx->ns);
fc->fs_private = &ctx->kfc;
if (fc->fs_type == &cgroup2_fs_type)
fc->ops = &cgroup_fs_context_ops;
else
fc->ops = &cgroup1_fs_context_ops;
if (fc->user_ns)
put_user_ns(fc->user_ns);
fc->user_ns = get_user_ns(ctx->ns->user_ns);
fc->global = true;
return 0;
}
static void cgroup_kill_sb(struct super_block *sb)
@ -2135,17 +2176,19 @@ static void cgroup_kill_sb(struct super_block *sb)
}
struct file_system_type cgroup_fs_type = {
.name = "cgroup",
.mount = cgroup_mount,
.kill_sb = cgroup_kill_sb,
.fs_flags = FS_USERNS_MOUNT,
.name = "cgroup",
.init_fs_context = cgroup_init_fs_context,
.parameters = &cgroup1_fs_parameters,
.kill_sb = cgroup_kill_sb,
.fs_flags = FS_USERNS_MOUNT,
};
static struct file_system_type cgroup2_fs_type = {
.name = "cgroup2",
.mount = cgroup_mount,
.kill_sb = cgroup_kill_sb,
.fs_flags = FS_USERNS_MOUNT,
.name = "cgroup2",
.init_fs_context = cgroup_init_fs_context,
.parameters = &cgroup2_fs_parameters,
.kill_sb = cgroup_kill_sb,
.fs_flags = FS_USERNS_MOUNT,
};
int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
@ -5280,7 +5323,6 @@ int cgroup_rmdir(struct kernfs_node *kn)
static struct kernfs_syscall_ops cgroup_kf_syscall_ops = {
.show_options = cgroup_show_options,
.remount_fs = cgroup_remount,
.mkdir = cgroup_mkdir,
.rmdir = cgroup_rmdir,
.show_path = cgroup_show_path,
@ -5347,11 +5389,12 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss, bool early)
*/
int __init cgroup_init_early(void)
{
static struct cgroup_sb_opts __initdata opts;
static struct cgroup_fs_context __initdata ctx;
struct cgroup_subsys *ss;
int i;
init_cgroup_root(&cgrp_dfl_root, &opts);
ctx.root = &cgrp_dfl_root;
init_cgroup_root(&ctx);
cgrp_dfl_root.cgrp.self.flags |= CSS_NO_REF;
RCU_INIT_POINTER(init_task.cgroups, &init_css_set);

54
kernel/cgroup/cpuset.c
View File

@ -39,6 +39,7 @@
#include <linux/memory.h>
#include <linux/export.h>
#include <linux/mount.h>
#include <linux/fs_context.h>
#include <linux/namei.h>
#include <linux/pagemap.h>
#include <linux/proc_fs.h>
@ -359,25 +360,52 @@ static inline bool is_in_v2_mode(void)
* users. If someone tries to mount the "cpuset" filesystem, we
* silently switch it to mount "cgroup" instead
*/
static struct dentry *cpuset_mount(struct file_system_type *fs_type,
int flags, const char *unused_dev_name, void *data)
static int cpuset_get_tree(struct fs_context *fc)
{
struct file_system_type *cgroup_fs = get_fs_type("cgroup");
struct dentry *ret = ERR_PTR(-ENODEV);
if (cgroup_fs) {
char mountopts[] =
"cpuset,noprefix,"
"release_agent=/sbin/cpuset_release_agent";
ret = cgroup_fs->mount(cgroup_fs, flags,
unused_dev_name, mountopts);
put_filesystem(cgroup_fs);
struct file_system_type *cgroup_fs;
struct fs_context *new_fc;
int ret;
cgroup_fs = get_fs_type("cgroup");
if (!cgroup_fs)
return -ENODEV;
new_fc = fs_context_for_mount(cgroup_fs, fc->sb_flags);
if (IS_ERR(new_fc)) {
ret = PTR_ERR(new_fc);
} else {
static const char agent_path[] = "/sbin/cpuset_release_agent";
ret = vfs_parse_fs_string(new_fc, "cpuset", NULL, 0);
if (!ret)
ret = vfs_parse_fs_string(new_fc, "noprefix", NULL, 0);
if (!ret)
ret = vfs_parse_fs_string(new_fc, "release_agent",
agent_path, sizeof(agent_path) - 1);
if (!ret)
ret = vfs_get_tree(new_fc);
if (!ret) { /* steal the result */
fc->root = new_fc->root;
new_fc->root = NULL;
}
put_fs_context(new_fc);
}
put_filesystem(cgroup_fs);
return ret;
}
static const struct fs_context_operations cpuset_fs_context_ops = {
.get_tree = cpuset_get_tree,
};
static int cpuset_init_fs_context(struct fs_context *fc)
{
fc->ops = &cpuset_fs_context_ops;
return 0;
}
static struct file_system_type cpuset_fs_type = {
.name = "cpuset",
.mount = cpuset_mount,
.name = "cpuset",
.init_fs_context = cpuset_init_fs_context,
};
/*

10
security/security.c
View File

@ -764,6 +764,16 @@ void security_bprm_committed_creds(struct linux_binprm *bprm)
call_void_hook(bprm_committed_creds, bprm);
}
int security_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc)
{
return call_int_hook(fs_context_dup, 0, fc, src_fc);
}
int security_fs_context_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
return call_int_hook(fs_context_parse_param, -ENOPARAM, fc, param);
}
int security_sb_alloc(struct super_block *sb)
{
return call_int_hook(sb_alloc_security, 0, sb);

88
security/selinux/hooks.c
View File

@ -48,6 +48,8 @@
#include <linux/fdtable.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <linux/tty.h>
@ -410,11 +412,11 @@ static inline int inode_doinit(struct inode *inode)
enum {
Opt_error = -1,
Opt_context = 1,
Opt_context = 0,
Opt_defcontext = 1,
Opt_fscontext = 2,
Opt_defcontext = 3,
Opt_rootcontext = 4,
Opt_seclabel = 5,
Opt_rootcontext = 3,
Opt_seclabel = 4,
};
#define A(s, has_arg) {#s, sizeof(#s) - 1, Opt_##s, has_arg}
@ -1067,6 +1069,7 @@ static int show_sid(struct seq_file *m, u32 sid)
if (!rc) {
bool has_comma = context && strchr(context, ',');
seq_putc(m, '=');
if (has_comma)
seq_putc(m, '\"');
seq_escape(m, context, "\"\n\\");
@ -1120,7 +1123,7 @@ static int selinux_sb_show_options(struct seq_file *m, struct super_block *sb)
}
if (sbsec->flags & SBLABEL_MNT) {
seq_putc(m, ',');
seq_puts(m, LABELSUPP_STR);
seq_puts(m, SECLABEL_STR);
}
return 0;
}
@ -2739,6 +2742,76 @@ static int selinux_umount(struct vfsmount *mnt, int flags)
FILESYSTEM__UNMOUNT, NULL);
}
static int selinux_fs_context_dup(struct fs_context *fc,
struct fs_context *src_fc)
{
const struct selinux_mnt_opts *src = src_fc->security;
struct selinux_mnt_opts *opts;
if (!src)
return 0;
fc->security = kzalloc(sizeof(struct selinux_mnt_opts), GFP_KERNEL);
if (!fc->security)
return -ENOMEM;
opts = fc->security;
if (src->fscontext) {
opts->fscontext = kstrdup(src->fscontext, GFP_KERNEL);
if (!opts->fscontext)
return -ENOMEM;
}
if (src->context) {
opts->context = kstrdup(src->context, GFP_KERNEL);
if (!opts->context)
return -ENOMEM;
}
if (src->rootcontext) {
opts->rootcontext = kstrdup(src->rootcontext, GFP_KERNEL);
if (!opts->rootcontext)
return -ENOMEM;
}
if (src->defcontext) {
opts->defcontext = kstrdup(src->defcontext, GFP_KERNEL);
if (!opts->defcontext)
return -ENOMEM;
}
return 0;
}
static const struct fs_parameter_spec selinux_param_specs[] = {
fsparam_string(CONTEXT_STR, Opt_context),
fsparam_string(DEFCONTEXT_STR, Opt_defcontext),
fsparam_string(FSCONTEXT_STR, Opt_fscontext),
fsparam_string(ROOTCONTEXT_STR, Opt_rootcontext),
fsparam_flag (SECLABEL_STR, Opt_seclabel),
{}
};
static const struct fs_parameter_description selinux_fs_parameters = {
.name = "SELinux",
.specs = selinux_param_specs,
};
static int selinux_fs_context_parse_param(struct fs_context *fc,
struct fs_parameter *param)
{
struct fs_parse_result result;
int opt, rc;
opt = fs_parse(fc, &selinux_fs_parameters, param, &result);
if (opt < 0)
return opt;
rc = selinux_add_opt(opt, param->string, &fc->security);
if (!rc) {
param->string = NULL;
rc = 1;
}
return rc;
}
/* inode security operations */
static int selinux_inode_alloc_security(struct inode *inode)
@ -6592,6 +6665,9 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(bprm_committing_creds, selinux_bprm_committing_creds),
LSM_HOOK_INIT(bprm_committed_creds, selinux_bprm_committed_creds),
LSM_HOOK_INIT(fs_context_dup, selinux_fs_context_dup),
LSM_HOOK_INIT(fs_context_parse_param, selinux_fs_context_parse_param),
LSM_HOOK_INIT(sb_alloc_security, selinux_sb_alloc_security),
LSM_HOOK_INIT(sb_free_security, selinux_sb_free_security),
LSM_HOOK_INIT(sb_eat_lsm_opts, selinux_sb_eat_lsm_opts),
@ -6837,6 +6913,8 @@ static __init int selinux_init(void)
else
pr_debug("SELinux: Starting in permissive mode\n");
fs_validate_description(&selinux_fs_parameters);
return 0;
}

10
security/selinux/include/security.h
View File

@ -59,11 +59,11 @@
#define SE_SBPROC 0x0200
#define SE_SBGENFS 0x0400
#define CONTEXT_STR "context="
#define FSCONTEXT_STR "fscontext="
#define ROOTCONTEXT_STR "rootcontext="
#define DEFCONTEXT_STR "defcontext="
#define LABELSUPP_STR "seclabel"
#define CONTEXT_STR "context"
#define FSCONTEXT_STR "fscontext"
#define ROOTCONTEXT_STR "rootcontext"
#define DEFCONTEXT_STR "defcontext"
#define SECLABEL_STR "seclabel"
struct netlbl_lsm_secattr;

19
security/smack/smack.h
View File

@ -196,22 +196,13 @@ struct smack_known_list_elem {
enum {
Opt_error = -1,
Opt_fsdefault = 1,
Opt_fsfloor = 2,
Opt_fshat = 3,
Opt_fsroot = 4,
Opt_fstransmute = 5,
Opt_fsdefault = 0,
Opt_fsfloor = 1,
Opt_fshat = 2,
Opt_fsroot = 3,
Opt_fstransmute = 4,
};
/*
* Mount options
*/
#define SMK_FSDEFAULT "smackfsdef="
#define SMK_FSFLOOR "smackfsfloor="
#define SMK_FSHAT "smackfshat="
#define SMK_FSROOT "smackfsroot="
#define SMK_FSTRANS "smackfstransmute="
#define SMACK_DELETE_OPTION "-DELETE"
#define SMACK_CIPSO_OPTION "-CIPSO"

92
security/smack/smack_lsm.c
View File

@ -43,6 +43,8 @@
#include <linux/shm.h>
#include <linux/binfmts.h>
#include <linux/parser.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include "smack.h"
#define TRANS_TRUE "TRUE"
@ -526,7 +528,6 @@ static int smack_syslog(int typefrom_file)
return rc;
}
/*
* Superblock Hooks.
*/
@ -631,6 +632,92 @@ static int smack_add_opt(int token, const char *s, void **mnt_opts)
return -EINVAL;
}
/**
* smack_fs_context_dup - Duplicate the security data on fs_context duplication
* @fc: The new filesystem context.
* @src_fc: The source filesystem context being duplicated.
*
* Returns 0 on success or -ENOMEM on error.
*/
static int smack_fs_context_dup(struct fs_context *fc,
struct fs_context *src_fc)
{
struct smack_mnt_opts *dst, *src = src_fc->security;
if (!src)
return 0;
fc->security = kzalloc(sizeof(struct smack_mnt_opts), GFP_KERNEL);
if (!fc->security)
return -ENOMEM;
dst = fc->security;
if (src->fsdefault) {
dst->fsdefault = kstrdup(src->fsdefault, GFP_KERNEL);
if (!dst->fsdefault)
return -ENOMEM;
}
if (src->fsfloor) {
dst->fsfloor = kstrdup(src->fsfloor, GFP_KERNEL);
if (!dst->fsfloor)
return -ENOMEM;
}
if (src->fshat) {
dst->fshat = kstrdup(src->fshat, GFP_KERNEL);
if (!dst->fshat)
return -ENOMEM;
}
if (src->fsroot) {
dst->fsroot = kstrdup(src->fsroot, GFP_KERNEL);
if (!dst->fsroot)
return -ENOMEM;
}
if (src->fstransmute) {
dst->fstransmute = kstrdup(src->fstransmute, GFP_KERNEL);
if (!dst->fstransmute)
return -ENOMEM;
}
return 0;
}
static const struct fs_parameter_spec smack_param_specs[] = {
fsparam_string("fsdefault", Opt_fsdefault),
fsparam_string("fsfloor", Opt_fsfloor),
fsparam_string("fshat", Opt_fshat),
fsparam_string("fsroot", Opt_fsroot),
fsparam_string("fstransmute", Opt_fstransmute),
{}
};
static const struct fs_parameter_description smack_fs_parameters = {
.name = "smack",
.specs = smack_param_specs,
};
/**
* smack_fs_context_parse_param - Parse a single mount parameter
* @fc: The new filesystem context being constructed.
* @param: The parameter.
*
* Returns 0 on success, -ENOPARAM to pass the parameter on or anything else on
* error.
*/
static int smack_fs_context_parse_param(struct fs_context *fc,
struct fs_parameter *param)
{
struct fs_parse_result result;
int opt, rc;
opt = fs_parse(fc, &smack_fs_parameters, param, &result);
if (opt < 0)
return opt;
rc = smack_add_opt(opt, param->string, &fc->security);
if (!rc)
param->string = NULL;
return rc;
}
static int smack_sb_eat_lsm_opts(char *options, void **mnt_opts)
{
char *from = options, *to = options;
@ -4495,6 +4582,9 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(ptrace_traceme, smack_ptrace_traceme),
LSM_HOOK_INIT(syslog, smack_syslog),
LSM_HOOK_INIT(fs_context_dup, smack_fs_context_dup),
LSM_HOOK_INIT(fs_context_parse_param, smack_fs_context_parse_param),
LSM_HOOK_INIT(sb_alloc_security, smack_sb_alloc_security),
LSM_HOOK_INIT(sb_free_security, smack_sb_free_security),
LSM_HOOK_INIT(sb_free_mnt_opts, smack_free_mnt_opts),