4750 Commits

Author SHA1 Message Date
Tyler Hicks
aa0c0227d3 ima: Use correct type for the args_p member of ima_rule_entry.lsm elements
Make args_p be of the char pointer type rather than have it be a void
pointer that gets casted to char pointer when it is used. It is a simple
NUL-terminated string as returned by match_strdup().

Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-07-20 13:28:14 -04:00
Tyler Hicks
39e5993d0d ima: Shallow copy the args_p member of ima_rule_entry.lsm elements
The args_p member is a simple string that is allocated by
ima_rule_init(). Shallow copy it like other non-LSM references in
ima_rule_entry structs.

There are no longer any necessary error path cleanups to do in
ima_lsm_copy_rule().

Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-07-20 13:28:13 -04:00
Tyler Hicks
5f3e92657b ima: Fail rule parsing when appraise_flag=blacklist is unsupportable
Verifying that a file hash is not blacklisted is currently only
supported for files with appended signatures (modsig).  In the future,
this might change.

For now, the "appraise_flag" option is only appropriate for appraise
actions and its "blacklist" value is only appropriate when
CONFIG_IMA_APPRAISE_MODSIG is enabled and "appraise_flag=blacklist" is
only appropriate when "appraise_type=imasig|modsig" is also present.
Make this clear at policy load so that IMA policy authors don't assume
that other uses of "appraise_flag=blacklist" are supported.

Fixes: 273df864cf74 ("ima: Check against blacklisted hashes for files with modsig")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reivewed-by: Nayna Jain <nayna@linux.ibm.com>
Tested-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-07-20 13:06:26 -04:00
Adrian Reber
124ea650d3 capabilities: Introduce CAP_CHECKPOINT_RESTORE
This patch introduces CAP_CHECKPOINT_RESTORE, a new capability facilitating
checkpoint/restore for non-root users.

Over the last years, The CRIU (Checkpoint/Restore In Userspace) team has
been asked numerous times if it is possible to checkpoint/restore a
process as non-root. The answer usually was: 'almost'.

The main blocker to restore a process as non-root was to control the PID
of the restored process. This feature available via the clone3 system
call, or via /proc/sys/kernel/ns_last_pid is unfortunately guarded by
CAP_SYS_ADMIN.

In the past two years, requests for non-root checkpoint/restore have
increased due to the following use cases:
* Checkpoint/Restore in an HPC environment in combination with a
  resource manager distributing jobs where users are always running as
  non-root. There is a desire to provide a way to checkpoint and
  restore long running jobs.
* Container migration as non-root
* We have been in contact with JVM developers who are integrating
  CRIU into a Java VM to decrease the startup time. These
  checkpoint/restore applications are not meant to be running with
  CAP_SYS_ADMIN.

We have seen the following workarounds:
* Use a setuid wrapper around CRIU:
  See https://github.com/FredHutch/slurm-examples/blob/master/checkpointer/lib/checkpointer/checkpointer-suid.c
* Use a setuid helper that writes to ns_last_pid.
  Unfortunately, this helper delegation technique is impossible to use
  with clone3, and is thus prone to races.
  See https://github.com/twosigma/set_ns_last_pid
* Cycle through PIDs with fork() until the desired PID is reached:
  This has been demonstrated to work with cycling rates of 100,000 PIDs/s
  See https://github.com/twosigma/set_ns_last_pid
* Patch out the CAP_SYS_ADMIN check from the kernel
* Run the desired application in a new user and PID namespace to provide
  a local CAP_SYS_ADMIN for controlling PIDs. This technique has limited
  use in typical container environments (e.g., Kubernetes) as /proc is
  typically protected with read-only layers (e.g., /proc/sys) for
  hardening purposes. Read-only layers prevent additional /proc mounts
  (due to proc's SB_I_USERNS_VISIBLE property), making the use of new
  PID namespaces limited as certain applications need access to /proc
  matching their PID namespace.

The introduced capability allows to:
* Control PIDs when the current user is CAP_CHECKPOINT_RESTORE capable
  for the corresponding PID namespace via ns_last_pid/clone3.
* Open files in /proc/pid/map_files when the current user is
  CAP_CHECKPOINT_RESTORE capable in the root namespace, useful for
  recovering files that are unreachable via the file system such as
  deleted files, or memfd files.

See corresponding selftest for an example with clone3().

Signed-off-by: Adrian Reber <areber@redhat.com>
Signed-off-by: Nicolas Viennot <Nicolas.Viennot@twosigma.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20200719100418.2112740-2-areber@redhat.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2020-07-19 20:14:42 +02:00
Tyler Hicks
eb624fe214 ima: Fail rule parsing when the KEY_CHECK hook is combined with an invalid cond
The KEY_CHECK function only supports the uid, pcr, and keyrings
conditionals. Make this clear at policy load so that IMA policy authors
don't assume that other conditionals are supported.

Fixes: 5808611cccb2 ("IMA: Add KEY_CHECK func to measure keys")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-07-16 21:53:55 -04:00
Tyler Hicks
db2045f589 ima: Fail rule parsing when the KEXEC_CMDLINE hook is combined with an invalid cond
The KEXEC_CMDLINE hook function only supports the pcr conditional. Make
this clear at policy load so that IMA policy authors don't assume that
other conditionals are supported.

Since KEXEC_CMDLINE's inception, ima_match_rules() has always returned
true on any loaded KEXEC_CMDLINE rule without any consideration for
other conditionals present in the rule. Make it clear that pcr is the
only supported KEXEC_CMDLINE conditional by returning an error during
policy load.

An example of why this is a problem can be explained with the following
rule:

 dont_measure func=KEXEC_CMDLINE obj_type=foo_t

An IMA policy author would have assumed that rule is valid because the
parser accepted it but the result was that measurements for all
KEXEC_CMDLINE operations would be disabled.

Fixes: b0935123a183 ("IMA: Define a new hook to measure the kexec boot command line arguments")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-07-16 21:53:55 -04:00
Tyler Hicks
712183437e ima: Fail rule parsing when buffer hook functions have an invalid action
Buffer based hook functions, such as KEXEC_CMDLINE and KEY_CHECK, can
only measure. The process_buffer_measurement() function quietly ignores
all actions except measure so make this behavior clear at the time of
policy load.

The parsing of the keyrings conditional had a check to ensure that it
was only specified with measure actions but the check should be on the
hook function and not the keyrings conditional since
"appraise func=KEY_CHECK" is not a valid rule.

Fixes: b0935123a183 ("IMA: Define a new hook to measure the kexec boot command line arguments")
Fixes: 5808611cccb2 ("IMA: Add KEY_CHECK func to measure keys")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-07-16 21:53:55 -04:00
Tyler Hicks
2bdd737c56 ima: Free the entire rule if it fails to parse
Use ima_free_rule() to fix memory leaks of allocated ima_rule_entry
members, such as .fsname and .keyrings, when an error is encountered
during rule parsing.

Set the args_p pointer to NULL after freeing it in the error path of
ima_lsm_rule_init() so that it isn't freed twice.

This fixes a memory leak seen when loading an rule that contains an
additional piece of allocated memory, such as an fsname, followed by an
invalid conditional:

 # echo "measure fsname=tmpfs bad=cond" > /sys/kernel/security/ima/policy
 -bash: echo: write error: Invalid argument
 # echo scan > /sys/kernel/debug/kmemleak
 # cat /sys/kernel/debug/kmemleak
 unreferenced object 0xffff98e7e4ece6c0 (size 8):
   comm "bash", pid 672, jiffies 4294791843 (age 21.855s)
   hex dump (first 8 bytes):
     74 6d 70 66 73 00 6b a5                          tmpfs.k.
   backtrace:
     [<00000000abab7413>] kstrdup+0x2e/0x60
     [<00000000f11ede32>] ima_parse_add_rule+0x7d4/0x1020
     [<00000000f883dd7a>] ima_write_policy+0xab/0x1d0
     [<00000000b17cf753>] vfs_write+0xde/0x1d0
     [<00000000b8ddfdea>] ksys_write+0x68/0xe0
     [<00000000b8e21e87>] do_syscall_64+0x56/0xa0
     [<0000000089ea7b98>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: f1b08bbcbdaf ("ima: define a new policy condition based on the filesystem name")
Fixes: 2b60c0ecedf8 ("IMA: Read keyrings= option from the IMA policy")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-07-16 21:53:55 -04:00
Tyler Hicks
465aee77aa ima: Free the entire rule when deleting a list of rules
Create a function, ima_free_rule(), to free all memory associated with
an ima_rule_entry. Use the new function to fix memory leaks of allocated
ima_rule_entry members, such as .fsname and .keyrings, when deleting a
list of rules.

Make the existing ima_lsm_free_rule() function specific to the LSM
audit rule array of an ima_rule_entry and require that callers make an
additional call to kfree to free the ima_rule_entry itself.

This fixes a memory leak seen when loading by a valid rule that contains
an additional piece of allocated memory, such as an fsname, followed by
an invalid rule that triggers a policy load failure:

 # echo -e "dont_measure fsname=securityfs\nbad syntax" > \
    /sys/kernel/security/ima/policy
 -bash: echo: write error: Invalid argument
 # echo scan > /sys/kernel/debug/kmemleak
 # cat /sys/kernel/debug/kmemleak
 unreferenced object 0xffff9bab67ca12c0 (size 16):
   comm "bash", pid 684, jiffies 4295212803 (age 252.344s)
   hex dump (first 16 bytes):
     73 65 63 75 72 69 74 79 66 73 00 6b 6b 6b 6b a5  securityfs.kkkk.
   backtrace:
     [<00000000adc80b1b>] kstrdup+0x2e/0x60
     [<00000000d504cb0d>] ima_parse_add_rule+0x7d4/0x1020
     [<00000000444825ac>] ima_write_policy+0xab/0x1d0
     [<000000002b7f0d6c>] vfs_write+0xde/0x1d0
     [<0000000096feedcf>] ksys_write+0x68/0xe0
     [<0000000052b544a2>] do_syscall_64+0x56/0xa0
     [<000000007ead1ba7>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: f1b08bbcbdaf ("ima: define a new policy condition based on the filesystem name")
Fixes: 2b60c0ecedf8 ("IMA: Read keyrings= option from the IMA policy")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-07-16 21:53:55 -04:00
Tyler Hicks
9ff8a616df ima: Have the LSM free its audit rule
Ask the LSM to free its audit rule rather than directly calling kfree().
Both AppArmor and SELinux do additional work in their audit_rule_free()
hooks. Fix memory leaks by allowing the LSMs to perform necessary work.

Fixes: b16942455193 ("ima: use the lsm policy update notifier")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Cc: Janne Karhunen <janne.karhunen@gmail.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-07-16 21:53:55 -04:00
Lakshmi Ramasubramanian
34e980bb83 IMA: Add audit log for failure conditions
process_buffer_measurement() and ima_alloc_key_entry() functions need to
log an audit message for auditing integrity measurement failures.

Add audit message in these two functions. Remove "pr_devel" log message
in process_buffer_measurement().

Sample audit messages:

[    6.303048] audit: type=1804 audit(1592506281.627:2): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=kernel op=measuring_key cause=ENOMEM comm="swapper/0" name=".builtin_trusted_keys" res=0 errno=-12

[    8.019432] audit: type=1804 audit(1592506283.344:10): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 op=measuring_kexec_cmdline cause=hashing_error comm="systemd" name="kexec-cmdline" res=0 errno=-22

Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-07-16 21:48:36 -04:00
Lakshmi Ramasubramanian
2f845882ec integrity: Add errno field in audit message
Error code is not included in the audit messages logged by
the integrity subsystem.

Define a new function integrity_audit_message() that takes error code
in the "errno" parameter. Add "errno" field in the audit messages logged
by the integrity subsystem and set the value passed in the "errno"
parameter.

[    6.303048] audit: type=1804 audit(1592506281.627:2): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=kernel op=measuring_key cause=ENOMEM comm="swapper/0" name=".builtin_trusted_keys" res=0 errno=-12

[    7.987647] audit: type=1802 audit(1592506283.312:9): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 op=policy_update cause=completed comm="systemd" res=1 errno=0

[    8.019432] audit: type=1804 audit(1592506283.344:10): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 op=measuring_kexec_cmdline cause=hashing_error comm="systemd" name="kexec-cmdline" res=0 errno=-22

Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: Steve Grubb <sgrubb@redhat.com>
Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-07-16 21:48:11 -04:00
Eric Biggers
beb4ee6770 Smack: fix use-after-free in smk_write_relabel_self()
smk_write_relabel_self() frees memory from the task's credentials with
no locking, which can easily cause a use-after-free because multiple
tasks can share the same credentials structure.

Fix this by using prepare_creds() and commit_creds() to correctly modify
the task's credentials.

Reproducer for "BUG: KASAN: use-after-free in smk_write_relabel_self":

	#include <fcntl.h>
	#include <pthread.h>
	#include <unistd.h>

	static void *thrproc(void *arg)
	{
		int fd = open("/sys/fs/smackfs/relabel-self", O_WRONLY);
		for (;;) write(fd, "foo", 3);
	}

	int main()
	{
		pthread_t t;
		pthread_create(&t, NULL, thrproc, NULL);
		thrproc(NULL);
	}

Reported-by: syzbot+e6416dabb497a650da40@syzkaller.appspotmail.com
Fixes: 38416e53936e ("Smack: limited capability for changing process label")
Cc: <stable@vger.kernel.org> # v4.4+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2020-07-14 11:19:58 -07:00
Ondrej Mosnacek
54b27f9287 selinux: complete the inlining of hashtab functions
Move (most of) the definitions of hashtab_search() and hashtab_insert()
to the header file. In combination with the previous patch, this avoids
calling the callbacks indirectly by function pointers and allows for
better optimization, leading to a drastic performance improvement of
these operations.

With this patch, I measured a speed up in the following areas (measured
on x86_64 F32 VM with 4 CPUs):
  1. Policy load (`load_policy`) - takes ~150 ms instead of ~230 ms.
  2. `chcon -R unconfined_u:object_r:user_tmp_t:s0:c381,c519 /tmp/linux-src`
     where /tmp/linux-src is an extracted linux-5.7 source tarball -
     takes ~522 ms instead of ~576 ms. This is because of many
     symtab_search() calls in string_to_context_struct() when there are
     many categories specified in the context.
  3. `stress-ng --msg 1 --msg-ops 10000000` - takes 12.41 s instead of
     13.95 s (consumes 18.6 s of kernel CPU time instead of 21.6 s).
     This is thanks to security_transition_sid() being ~43% faster after
     this patch.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-07-09 19:08:16 -04:00
Ondrej Mosnacek
24def7bb92 selinux: prepare for inlining of hashtab functions
Refactor searching and inserting into hashtabs to pave the way for
converting hashtab_search() and hashtab_insert() to inline functions in
the next patch. This will avoid indirect calls and allow the compiler to
better optimize individual callers, leading to a significant performance
improvement.

In order to avoid the indirect calls, the key hashing and comparison
callbacks need to be extracted from the hashtab struct and passed
directly to hashtab_search()/_insert() by the callers so that the
callback address is always known at compile time. The kernel's
rhashtable library (<linux/rhashtable*.h>) does the same thing.

This of course makes the hashtab functions slightly easier to misuse by
passing a wrong callback set, but unfortunately there is no better way
to implement a hash table that is both generic and efficient in C. This
patch tries to somewhat mitigate this by only calling the hashtab
functions in the same file where the corresponding callbacks are
defined (wrapping them into more specialized functions as needed).

Note that this patch doesn't bring any benefit without also moving the
definitions of hashtab_search() and -_insert() to the header file, which
is done in a follow-up patch for easier review of the hashtab.c changes
in this patch.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-07-09 19:05:36 -04:00
Ondrej Mosnacek
237389e301 selinux: specialize symtab insert and search functions
This encapsulates symtab a little better and will help with further
refactoring later.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-07-08 20:21:43 -04:00
Richard Guy Briggs
d7481b24b8 audit: issue CWD record to accompany LSM_AUDIT_DATA_* records
The LSM_AUDIT_DATA_* records for PATH, FILE, IOCTL_OP, DENTRY and INODE
are incomplete without the task context of the AUDIT Current Working
Directory record.  Add it.

This record addition can't use audit_dummy_context to determine whether
or not to store the record information since the LSM_AUDIT_DATA_*
records are initiated by various LSMs independent of any audit rules.
context->in_syscall is used to determine if it was called in user
context like audit_getname.

Please see the upstream issue
https://github.com/linux-audit/audit-kernel/issues/96

Adapted from Vladis Dronov's v2 patch.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-07-08 19:02:11 -04:00
lihao
2c3d8dfece selinux: Fix spelling mistakes in the comments
Fix spelling mistakes in the comments
    quering==>querying

Signed-off-by: lihao <fly.lihao@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-07-08 12:15:52 -04:00
Christoph Hellwig
a1f9b1c043 integrity/ima: switch to using __kernel_read
__kernel_read has a bunch of additional sanity checks, and this moves
the set_fs out of non-core code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-08 08:27:57 +02:00
Linus Torvalds
615bc218d6 Two simple fixes for v5.8:
1) Fix hook iteration and default value for inode_copy_up_xattr
 	from KP Singh <kpsingh@google.com>
 
 2) Fix the key_permission LSM hook function type
 	from Sami Tolvanen <samitolvanen@google.com>
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Merge tag 'fixes-v5.8-rc3-a' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull security subsystem fixes from James Morris:
 "Two simple fixes for v5.8:

   - Fix hook iteration and default value for inode_copy_up_xattr
     (KP Singh)

   - Fix the key_permission LSM hook function type (Sami Tolvanen)"

* tag 'fixes-v5.8-rc3-a' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  security: Fix hook iteration and default value for inode_copy_up_xattr
  security: fix the key_permission LSM hook function type
2020-06-30 12:21:53 -07:00
Ethan Edwards
65d96351b1 selinux: fixed a checkpatch warning with the sizeof macro
`sizeof buf` changed to `sizeof(buf)`

Signed-off-by: Ethan Edwards <ethancarteredwards@gmail.com>
[PM: rewrote the subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-06-29 19:26:17 -04:00
Maurizio Drocco
20c59ce010 ima: extend boot_aggregate with kernel measurements
Registers 8-9 are used to store measurements of the kernel and its
command line (e.g., grub2 bootloader with tpm module enabled). IMA
should include them in the boot aggregate. Registers 8-9 should be
only included in non-SHA1 digests to avoid ambiguity.

Signed-off-by: Maurizio Drocco <maurizio.drocco@ibm.com>
Reviewed-by: Bruno Meneguele <bmeneg@redhat.com>
Tested-by: Bruno Meneguele <bmeneg@redhat.com>  (TPM 1.2, TPM 2.0)
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-06-24 20:47:24 -04:00
Christoph Hellwig
3f1266f1f8 block: move block-related definitions out of fs.h
Move most of the block related definition out of fs.h into more suitable
headers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-24 09:16:02 -06:00
Stephen Smalley
7383c0f94d selinux: log error messages on required process class / permissions
In general SELinux no longer treats undefined object classes or permissions
in the policy as a fatal error, instead handling them in accordance with
handle_unknown. However, the process class and process transition and
dyntransition permissions are still required to be defined due to
dependencies on these definitions for default labeling behaviors,
role and range transitions in older policy versions that lack an explicit
class field, and role allow checking.  Log error messages in these cases
since otherwise the policy load will fail silently with no indication
to the user as to the underlying cause.  While here, fix the checking for
process transition / dyntransition so that omitting either permission is
handled as an error; both are needed in order to ensure that role allow
checking is consistently applied.

Reported-by: bauen1 <j2468h@googlemail.com>
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-06-23 20:57:01 -04:00
Jonathan Lebon
c8e222616c selinux: allow reading labels before policy is loaded
This patch does for `getxattr` what commit 3e3e24b42043 ("selinux: allow
labeling before policy is loaded") did for `setxattr`; it allows
querying the current SELinux label on disk before the policy is loaded.

One of the motivations described in that commit message also drives this
patch: for Fedora CoreOS (and eventually RHEL CoreOS), we want to be
able to move the root filesystem for example, from xfs to ext4 on RAID,
on first boot, at initrd time.[1]

Because such an operation works at the filesystem level, we need to be
able to read the SELinux labels first from the original root, and apply
them to the files of the new root. The previous commit enabled the
second part of this process; this commit enables the first part.

[1] https://github.com/coreos/fedora-coreos-tracker/issues/94

Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Jonathan Lebon <jlebon@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-06-23 20:42:38 -04:00
KP Singh
23e390cdbe security: Fix hook iteration and default value for inode_copy_up_xattr
inode_copy_up_xattr returns 0 to indicate the acceptance of the xattr
and 1 to reject it. If the LSM does not know about the xattr, it's
expected to return -EOPNOTSUPP, which is the correct default value for
this hook. BPF LSM, currently, uses 0 as the default value and thereby
falsely allows all overlay fs xattributes to be copied up.

The iteration logic is also updated from the "bail-on-fail"
call_int_hook to continue on the non-decisive -EOPNOTSUPP and bail out
on other values.

Fixes: 98e828a0650f ("security: Refactor declaration of LSM hooks")
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: James Morris <jmorris@namei.org>
2020-06-23 16:39:23 -07:00
Linus Torvalds
817d914d17 selinux/stable-5.8 PR 20200621
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Merge tag 'selinux-pr-20200621' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull SELinux fixes from Paul Moore:
 "Three small patches to fix problems in the SELinux code, all found via
  clang.

  Two patches fix potential double-free conditions and one fixes an
  undefined return value"

* tag 'selinux-pr-20200621' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: fix undefined return of cond_evaluate_expr
  selinux: fix a double free in cond_read_node()/cond_read_list()
  selinux: fix double free
2020-06-21 15:41:24 -07:00
Tom Rix
8231b0b9c3 selinux: fix undefined return of cond_evaluate_expr
clang static analysis reports an undefined return

security/selinux/ss/conditional.c:79:2: warning: Undefined or garbage value returned to caller [core.uninitialized.UndefReturn]
        return s[0];
        ^~~~~~~~~~~

static int cond_evaluate_expr( ...
{
	u32 i;
	int s[COND_EXPR_MAXDEPTH];

	for (i = 0; i < expr->len; i++)
	  ...

	return s[0];

When expr->len is 0, the loop which sets s[0] never runs.

So return -1 if the loop never runs.

Cc: stable@vger.kernel.org
Signed-off-by: Tom Rix <trix@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-06-17 17:36:40 -04:00
Tom Rix
aa449a7965 selinux: fix a double free in cond_read_node()/cond_read_list()
Clang static analysis reports this double free error

security/selinux/ss/conditional.c:139:2: warning: Attempt to free released memory [unix.Malloc]
        kfree(node->expr.nodes);
        ^~~~~~~~~~~~~~~~~~~~~~~

When cond_read_node fails, it calls cond_node_destroy which frees the
node but does not poison the entry in the node list.  So when it
returns to its caller cond_read_list, cond_read_list deletes the
partial list.  The latest entry in the list will be deleted twice.

So instead of freeing the node in cond_read_node, let list freeing in
code_read_list handle the freeing the problem node along with all of the
earlier nodes.

Because cond_read_node no longer does any error handling, the goto's
the error case are redundant.  Instead just return the error code.

Cc: stable@vger.kernel.org
Fixes: 60abd3181db2 ("selinux: convert cond_list to array")
Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-06-16 20:25:19 -04:00
glider@google.com
f0fe00d497 security: allow using Clang's zero initialization for stack variables
In addition to -ftrivial-auto-var-init=pattern (used by
CONFIG_INIT_STACK_ALL now) Clang also supports zero initialization for
locals enabled by -ftrivial-auto-var-init=zero. The future of this flag
is still being debated (see https://bugs.llvm.org/show_bug.cgi?id=45497).
Right now it is guarded by another flag,
-enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang,
which means it may not be supported by future Clang releases. Another
possible resolution is that -ftrivial-auto-var-init=zero will persist
(as certain users have already started depending on it), but the name
of the guard flag will change.

In the meantime, zero initialization has proven itself as a good
production mitigation measure against uninitialized locals. Unlike pattern
initialization, which has a higher chance of triggering existing bugs,
zero initialization provides safe defaults for strings, pointers, indexes,
and sizes. On the other hand, pattern initialization remains safer for
return values. Chrome OS and Android are moving to using zero
initialization for production builds.

Performance-wise, the difference between pattern and zero initialization
is usually negligible, although the generated code for zero
initialization is more compact.

This patch renames CONFIG_INIT_STACK_ALL to CONFIG_INIT_STACK_ALL_PATTERN
and introduces another config option, CONFIG_INIT_STACK_ALL_ZERO, that
enables zero initialization for locals if the corresponding flags are
supported by Clang.

Cc: Kees Cook <keescook@chromium.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/r/20200616083435.223038-1-glider@google.com
Reviewed-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-06-16 02:06:23 -07:00
Gustavo A. R. Silva
eb492c627a ima: Replace zero-length array with flexible-array
There is a regular need in the kernel to provide a way to declare having a
dynamically sized set of trailing elements in a structure. Kernel code should
always use “flexible array members”[1] for these cases. The older style of
one-element or zero-length arrays should no longer be used[2].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://github.com/KSPP/linux/issues/21

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-06-15 23:08:32 -05:00
Linus Torvalds
4a87b197c1 Add additional LSM hooks for SafeSetID
SafeSetID is capable of making allow/deny decisions for set*uid calls
 on a system, and we want to add similar functionality for set*gid
 calls. The work to do that is not yet complete, so probably won't make
 it in for v5.8, but we are looking to get this simple patch in for
 v5.8 since we have it ready. We are planning on the rest of the work
 for extending the SafeSetID LSM being merged during the v5.9 merge
 window.
 
 This patch was sent to the security mailing list and there were no objections.
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Merge tag 'LSM-add-setgid-hook-5.8-author-fix' of git://github.com/micah-morton/linux

Pull SafeSetID update from Micah Morton:
 "Add additional LSM hooks for SafeSetID

  SafeSetID is capable of making allow/deny decisions for set*uid calls
  on a system, and we want to add similar functionality for set*gid
  calls.

  The work to do that is not yet complete, so probably won't make it in
  for v5.8, but we are looking to get this simple patch in for v5.8
  since we have it ready.

  We are planning on the rest of the work for extending the SafeSetID
  LSM being merged during the v5.9 merge window"

* tag 'LSM-add-setgid-hook-5.8-author-fix' of git://github.com/micah-morton/linux:
  security: Add LSM hooks to set*gid syscalls
2020-06-14 11:39:31 -07:00
Thomas Cedeno
39030e1351 security: Add LSM hooks to set*gid syscalls
The SafeSetID LSM uses the security_task_fix_setuid hook to filter
set*uid() syscalls according to its configured security policy. In
preparation for adding analagous support in the LSM for set*gid()
syscalls, we add the requisite hook here. Tested by putting print
statements in the security_task_fix_setgid hook and seeing them get hit
during kernel boot.

Signed-off-by: Thomas Cedeno <thomascedeno@google.com>
Signed-off-by: Micah Morton <mortonm@chromium.org>
2020-06-14 10:52:02 -07:00
Linus Torvalds
6adc19fd13 Kbuild updates for v5.8 (2nd)
- fix build rules in binderfs sample
 
  - fix build errors when Kbuild recurses to the top Makefile
 
  - covert '---help---' in Kconfig to 'help'
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Merge tag 'kbuild-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull more Kbuild updates from Masahiro Yamada:

 - fix build rules in binderfs sample

 - fix build errors when Kbuild recurses to the top Makefile

 - covert '---help---' in Kconfig to 'help'

* tag 'kbuild-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  treewide: replace '---help---' in Kconfig files with 'help'
  kbuild: fix broken builds because of GZIP,BZIP2,LZOP variables
  samples: binderfs: really compile this sample and fix build issues
2020-06-13 13:29:16 -07:00
Masahiro Yamada
a7f7f6248d treewide: replace '---help---' in Kconfig files with 'help'
Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.

This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.

There are a variety of indentation styles found.

  a) 4 spaces + '---help---'
  b) 7 spaces + '---help---'
  c) 8 spaces + '---help---'
  d) 1 space + 1 tab + '---help---'
  e) 1 tab + '---help---'    (correct indentation)
  f) 1 tab + 1 space + '---help---'
  g) 1 tab + 2 spaces + '---help---'

In order to convert all of them to 1 tab + 'help', I ran the
following commend:

  $ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-14 01:57:21 +09:00
Linus Torvalds
6c32978414 Notifications over pipes + Keyring notifications
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Merge tag 'notifications-20200601' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull notification queue from David Howells:
 "This adds a general notification queue concept and adds an event
  source for keys/keyrings, such as linking and unlinking keys and
  changing their attributes.

  Thanks to Debarshi Ray, we do have a pull request to use this to fix a
  problem with gnome-online-accounts - as mentioned last time:

     https://gitlab.gnome.org/GNOME/gnome-online-accounts/merge_requests/47

  Without this, g-o-a has to constantly poll a keyring-based kerberos
  cache to find out if kinit has changed anything.

  [ There are other notification pending: mount/sb fsinfo notifications
    for libmount that Karel Zak and Ian Kent have been working on, and
    Christian Brauner would like to use them in lxc, but let's see how
    this one works first ]

  LSM hooks are included:

   - A set of hooks are provided that allow an LSM to rule on whether or
     not a watch may be set. Each of these hooks takes a different
     "watched object" parameter, so they're not really shareable. The
     LSM should use current's credentials. [Wanted by SELinux & Smack]

   - A hook is provided to allow an LSM to rule on whether or not a
     particular message may be posted to a particular queue. This is
     given the credentials from the event generator (which may be the
     system) and the watch setter. [Wanted by Smack]

  I've provided SELinux and Smack with implementations of some of these
  hooks.

  WHY
  ===

  Key/keyring notifications are desirable because if you have your
  kerberos tickets in a file/directory, your Gnome desktop will monitor
  that using something like fanotify and tell you if your credentials
  cache changes.

  However, we also have the ability to cache your kerberos tickets in
  the session, user or persistent keyring so that it isn't left around
  on disk across a reboot or logout. Keyrings, however, cannot currently
  be monitored asynchronously, so the desktop has to poll for it - not
  so good on a laptop. This facility will allow the desktop to avoid the
  need to poll.

  DESIGN DECISIONS
  ================

   - The notification queue is built on top of a standard pipe. Messages
     are effectively spliced in. The pipe is opened with a special flag:

        pipe2(fds, O_NOTIFICATION_PIPE);

     The special flag has the same value as O_EXCL (which doesn't seem
     like it will ever be applicable in this context)[?]. It is given up
     front to make it a lot easier to prohibit splice&co from accessing
     the pipe.

     [?] Should this be done some other way?  I'd rather not use up a new
         O_* flag if I can avoid it - should I add a pipe3() system call
         instead?

     The pipe is then configured::

        ioctl(fds[1], IOC_WATCH_QUEUE_SET_SIZE, queue_depth);
        ioctl(fds[1], IOC_WATCH_QUEUE_SET_FILTER, &filter);

     Messages are then read out of the pipe using read().

   - It should be possible to allow write() to insert data into the
     notification pipes too, but this is currently disabled as the
     kernel has to be able to insert messages into the pipe *without*
     holding pipe->mutex and the code to make this work needs careful
     auditing.

   - sendfile(), splice() and vmsplice() are disabled on notification
     pipes because of the pipe->mutex issue and also because they
     sometimes want to revert what they just did - but one or more
     notification messages might've been interleaved in the ring.

   - The kernel inserts messages with the wait queue spinlock held. This
     means that pipe_read() and pipe_write() have to take the spinlock
     to update the queue pointers.

   - Records in the buffer are binary, typed and have a length so that
     they can be of varying size.

     This allows multiple heterogeneous sources to share a common
     buffer; there are 16 million types available, of which I've used
     just a few, so there is scope for others to be used. Tags may be
     specified when a watchpoint is created to help distinguish the
     sources.

   - Records are filterable as types have up to 256 subtypes that can be
     individually filtered. Other filtration is also available.

   - Notification pipes don't interfere with each other; each may be
     bound to a different set of watches. Any particular notification
     will be copied to all the queues that are currently watching for it
     - and only those that are watching for it.

   - When recording a notification, the kernel will not sleep, but will
     rather mark a queue as having lost a message if there's
     insufficient space. read() will fabricate a loss notification
     message at an appropriate point later.

   - The notification pipe is created and then watchpoints are attached
     to it, using one of:

        keyctl_watch_key(KEY_SPEC_SESSION_KEYRING, fds[1], 0x01);
        watch_mount(AT_FDCWD, "/", 0, fd, 0x02);
        watch_sb(AT_FDCWD, "/mnt", 0, fd, 0x03);

     where in both cases, fd indicates the queue and the number after is
     a tag between 0 and 255.

   - Watches are removed if either the notification pipe is destroyed or
     the watched object is destroyed. In the latter case, a message will
     be generated indicating the enforced watch removal.

  Things I want to avoid:

   - Introducing features that make the core VFS dependent on the
     network stack or networking namespaces (ie. usage of netlink).

   - Dumping all this stuff into dmesg and having a daemon that sits
     there parsing the output and distributing it as this then puts the
     responsibility for security into userspace and makes handling
     namespaces tricky. Further, dmesg might not exist or might be
     inaccessible inside a container.

   - Letting users see events they shouldn't be able to see.

  TESTING AND MANPAGES
  ====================

   - The keyutils tree has a pipe-watch branch that has keyctl commands
     for making use of notifications. Proposed manual pages can also be
     found on this branch, though a couple of them really need to go to
     the main manpages repository instead.

     If the kernel supports the watching of keys, then running "make
     test" on that branch will cause the testing infrastructure to spawn
     a monitoring process on the side that monitors a notifications pipe
     for all the key/keyring changes induced by the tests and they'll
     all be checked off to make sure they happened.

        https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/keyutils.git/log/?h=pipe-watch

   - A test program is provided (samples/watch_queue/watch_test) that
     can be used to monitor for keyrings, mount and superblock events.
     Information on the notifications is simply logged to stdout"

* tag 'notifications-20200601' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  smack: Implement the watch_key and post_notification hooks
  selinux: Implement the watch_key security hook
  keys: Make the KEY_NEED_* perms an enum rather than a mask
  pipe: Add notification lossage handling
  pipe: Allow buffers to be marked read-whole-or-error for notifications
  Add sample notification program
  watch_queue: Add a key/keyring notification facility
  security: Add hooks to rule on setting a watch
  pipe: Add general notification queue support
  pipe: Add O_NOTIFICATION_PIPE
  security: Add a hook for the point of notification insertion
  uapi: General notification queue definitions
2020-06-13 09:56:21 -07:00
Linus Torvalds
923ea1631e ima: mprotect performance fix
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Merge tag 'integrity-v5.8-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

Pull integrity fix from Mimi Zohar:
 "ima mprotect performance fix"

* tag 'integrity-v5.8-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  ima: fix mprotect checking
2020-06-12 12:02:41 -07:00
Mimi Zohar
4235b1a4ef ima: fix mprotect checking
Make sure IMA is enabled before checking mprotect change.  Addresses
report of a 3.7% regression of boot-time.dhcp.

Fixes: 8eb613c0b8f1 ("ima: verify mprotect change is consistent with mmap policy")
Reported-by: kernel test robot <rong.a.chen@intel.com>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Tested-by: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-06-12 11:30:18 -04:00
Tom Rix
65de50969a selinux: fix double free
Clang's static analysis tool reports these double free memory errors.

security/selinux/ss/services.c:2987:4: warning: Attempt to free released memory [unix.Malloc]
                        kfree(bnames[i]);
                        ^~~~~~~~~~~~~~~~
security/selinux/ss/services.c:2990:2: warning: Attempt to free released memory [unix.Malloc]
        kfree(bvalues);
        ^~~~~~~~~~~~~~

So improve the security_get_bools error handling by freeing these variables
and setting their return pointers to NULL and the return len to 0

Cc: stable@vger.kernel.org
Signed-off-by: Tom Rix <trix@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-06-10 22:10:35 -04:00
Linus Torvalds
52435c86bf overlayfs update for 5.8
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Merge tag 'ovl-update-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs updates from Miklos Szeredi:
 "Fixes:

   - Resolve mount option conflicts consistently

   - Sync before remount R/O

   - Fix file handle encoding corner cases

   - Fix metacopy related issues

   - Fix an unintialized return value

   - Add missing permission checks for underlying layers

  Optimizations:

   - Allow multipe whiteouts to share an inode

   - Optimize small writes by inheriting SB_NOSEC from upper layer

   - Do not call ->syncfs() multiple times for sync(2)

   - Do not cache negative lookups on upper layer

   - Make private internal mounts longterm"

* tag 'ovl-update-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (27 commits)
  ovl: remove unnecessary lock check
  ovl: make oip->index bool
  ovl: only pass ->ki_flags to ovl_iocb_to_rwf()
  ovl: make private mounts longterm
  ovl: get rid of redundant members in struct ovl_fs
  ovl: add accessor for ofs->upper_mnt
  ovl: initialize error in ovl_copy_xattr
  ovl: drop negative dentry in upper layer
  ovl: check permission to open real file
  ovl: call secutiry hook in ovl_real_ioctl()
  ovl: verify permissions in ovl_path_open()
  ovl: switch to mounter creds in readdir
  ovl: pass correct flags for opening real directory
  ovl: fix redirect traversal on metacopy dentries
  ovl: initialize OVL_UPPERDATA in ovl_lookup()
  ovl: use only uppermetacopy state in ovl_lookup()
  ovl: simplify setting of origin for index lookup
  ovl: fix out of bounds access warning in ovl_check_fb_len()
  ovl: return required buffer size for file handles
  ovl: sync dirty data when remounting to ro mode
  ...
2020-06-09 15:40:50 -07:00
Linus Torvalds
595a56ac1b linux-kselftest-kunit-5.8-rc1
This Kunit update for Linux 5.8-rc1 consists of:
 
 - Several config fragment fixes from Anders Roxell to improve
   test coverage.
 - Improvements to kunit run script to use defconfig as default and
   restructure the code for config/build/exec/parse from Vitor Massaru Iha
   and David Gow.
 - Miscellaneous documentation warn fix.
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Merge tag 'linux-kselftest-kunit-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull Kunit updates from Shuah Khan:
 "This consists of:

   - Several config fragment fixes from Anders Roxell to improve test
     coverage.

   - Improvements to kunit run script to use defconfig as default and
     restructure the code for config/build/exec/parse from Vitor Massaru
     Iha and David Gow.

   - Miscellaneous documentation warn fix"

* tag 'linux-kselftest-kunit-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  security: apparmor: default KUNIT_* fragments to KUNIT_ALL_TESTS
  fs: ext4: default KUNIT_* fragments to KUNIT_ALL_TESTS
  drivers: base: default KUNIT_* fragments to KUNIT_ALL_TESTS
  lib: Kconfig.debug: default KUNIT_* fragments to KUNIT_ALL_TESTS
  kunit: default KUNIT_* fragments to KUNIT_ALL_TESTS
  kunit: Kconfig: enable a KUNIT_ALL_TESTS fragment
  kunit: Fix TabError, remove defconfig code and handle when there is no kunitconfig
  kunit: use KUnit defconfig by default
  kunit: use --build_dir=.kunit as default
  Documentation: test.h - fix warnings
  kunit: kunit_tool: Separate out config/build/exec/parse
2020-06-09 10:04:47 -07:00
Michel Lespinasse
c1e8d7c6a7 mmap locking API: convert mmap_sem comments
Convert comments that reference mmap_sem to reference mmap_lock instead.

[akpm@linux-foundation.org: fix up linux-next leftovers]
[akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil]
[akpm@linux-foundation.org: more linux-next fixups, per Michel]

Signed-off-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 09:39:14 -07:00
Linus Torvalds
a2b447066c Tag summary
+ Features
   - Replace zero-length array with flexible-array
   - add a valid state flags check
   - add consistency check between state and dfa diff encode flags
   - add apparmor subdir to proc attr interface
   - fail unpack if profile mode is unknown
   - add outofband transition and use it in xattr match
   - ensure that dfa state tables have entries
 
 + Cleanups
   - Use true and false for bool variable
   - Remove semicolon
   - Clean code by removing redundant instructions
   - Replace two seq_printf() calls by seq_puts() in aa_label_seq_xprint()
   - remove duplicate check of xattrs on profile attachment
   - remove useless aafs_create_symlink
 
 + Bug fixes
   - Fix memory leak of profile proxy
   - fix introspection of of task mode for unconfined tasks
   - fix nnp subset test for unconfined
   - check/put label on apparmor_sk_clone_security()
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Merge tag 'apparmor-pr-2020-06-07' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor

Pull apparmor updates from John Johansen:
 "Features:
   - Replace zero-length array with flexible-array
   - add a valid state flags check
   - add consistency check between state and dfa diff encode flags
   - add apparmor subdir to proc attr interface
   - fail unpack if profile mode is unknown
   - add outofband transition and use it in xattr match
   - ensure that dfa state tables have entries

  Cleanups:
   - Use true and false for bool variable
   - Remove semicolon
   - Clean code by removing redundant instructions
   - Replace two seq_printf() calls by seq_puts() in aa_label_seq_xprint()
   - remove duplicate check of xattrs on profile attachment
   - remove useless aafs_create_symlink

  Bug fixes:
   - Fix memory leak of profile proxy
   - fix introspection of of task mode for unconfined tasks
   - fix nnp subset test for unconfined
   - check/put label on apparmor_sk_clone_security()"

* tag 'apparmor-pr-2020-06-07' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor:
  apparmor: Fix memory leak of profile proxy
  apparmor: fix introspection of of task mode for unconfined tasks
  apparmor: check/put label on apparmor_sk_clone_security()
  apparmor: Use true and false for bool variable
  security/apparmor/label.c: Clean code by removing redundant instructions
  apparmor: Replace zero-length array with flexible-array
  apparmor: ensure that dfa state tables have entries
  apparmor: remove duplicate check of xattrs on profile attachment.
  apparmor: add outofband transition and use it in xattr match
  apparmor: fail unpack if profile mode is unknown
  apparmor: fix nnp subset test for unconfined
  apparmor: remove useless aafs_create_symlink
  apparmor: add proc subdir to attrs
  apparmor: add consistency check between state and dfa diff encode flags
  apparmor: add a valid state flags check
  AppArmor: Remove semicolon
  apparmor: Replace two seq_printf() calls by seq_puts() in aa_label_seq_xprint()
2020-06-07 16:04:49 -07:00
Roberto Sassu
8b8c704d91 ima: Remove __init annotation from ima_pcrread()
Commit 6cc7c266e5b4 ("ima: Call ima_calc_boot_aggregate() in
ima_eventdigest_init()") added a call to ima_calc_boot_aggregate() so that
the digest can be recalculated for the boot_aggregate measurement entry if
the 'd' template field has been requested. For the 'd' field, only SHA1 and
MD5 digests are accepted.

Given that ima_eventdigest_init() does not have the __init annotation, all
functions called should not have it. This patch removes __init from
ima_pcrread().

Cc: stable@vger.kernel.org
Fixes:  6cc7c266e5b4 ("ima: Call ima_calc_boot_aggregate() in ima_eventdigest_init()")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-07 16:03:09 -07:00
John Johansen
3622ad25d4 apparmor: Fix memory leak of profile proxy
When the proxy isn't replaced and the profile is removed, the proxy
is being leaked resulting in a kmemleak check message of

unreferenced object 0xffff888077a3a490 (size 16):
  comm "apparmor_parser", pid 128041, jiffies 4322684109 (age 1097.028s)
  hex dump (first 16 bytes):
    03 00 00 00 00 00 00 00 b0 92 fd 4b 81 88 ff ff  ...........K....
  backtrace:
    [<0000000084d5daf2>] aa_alloc_proxy+0x58/0xe0
    [<00000000ecc0e21a>] aa_alloc_profile+0x159/0x1a0
    [<000000004cc9ce15>] unpack_profile+0x275/0x1c40
    [<000000007332b3ca>] aa_unpack+0x1e7/0x7e0
    [<00000000e25e31bd>] aa_replace_profiles+0x18a/0x1d10
    [<00000000350d9415>] policy_update+0x237/0x650
    [<000000003fbf934e>] profile_load+0x122/0x160
    [<0000000047f7b781>] vfs_write+0x139/0x290
    [<000000008ad12358>] ksys_write+0xcd/0x170
    [<000000001a9daa7b>] do_syscall_64+0x70/0x310
    [<00000000b9efb0cf>] entry_SYSCALL_64_after_hwframe+0x49/0xb3

Make sure to cleanup the profile's embedded label which will result
on the proxy being properly freed.

Fixes: 637f688dc3dc ("apparmor: switch from profiles to using labels on contexts")
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-06-07 13:38:55 -07:00
John Johansen
dd2569fbb0 apparmor: fix introspection of of task mode for unconfined tasks
Fix two issues with introspecting the task mode.

1. If a task is attached to a unconfined profile that is not the
   ns->unconfined profile then. Mode the mode is always reported
   as -

      $ ps -Z
      LABEL                               PID TTY          TIME CMD
      unconfined                         1287 pts/0    00:00:01 bash
      test (-)                           1892 pts/0    00:00:00 ps

   instead of the correct value of (unconfined) as shown below

      $ ps -Z
      LABEL                               PID TTY          TIME CMD
      unconfined                         2483 pts/0    00:00:01 bash
      test (unconfined)                  3591 pts/0    00:00:00 ps

2. if a task is confined by a stack of profiles that are unconfined
   the output of label mode is again the incorrect value of (-) like
   above, instead of (unconfined). This is because the visibile
   profile count increment is skipped by the special casing of
   unconfined.

Fixes: f1bd904175e8 ("apparmor: add the base fns() for domain labels")
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-06-07 13:38:55 -07:00
Mauricio Faria de Oliveira
3b646abc5b apparmor: check/put label on apparmor_sk_clone_security()
Currently apparmor_sk_clone_security() does not check for existing
label/peer in the 'new' struct sock; it just overwrites it, if any
(with another reference to the label of the source sock.)

    static void apparmor_sk_clone_security(const struct sock *sk,
                                           struct sock *newsk)
    {
            struct aa_sk_ctx *ctx = SK_CTX(sk);
            struct aa_sk_ctx *new = SK_CTX(newsk);

            new->label = aa_get_label(ctx->label);
            new->peer = aa_get_label(ctx->peer);
    }

This might leak label references, which might overflow under load.
Thus, check for and put labels, to prevent such errors.

Note this is similarly done on:

    static int apparmor_socket_post_create(struct socket *sock, ...)
    ...
            if (sock->sk) {
                    struct aa_sk_ctx *ctx = SK_CTX(sock->sk);

                    aa_put_label(ctx->label);
                    ctx->label = aa_get_label(label);
            }
    ...

Context:
-------

The label reference count leak is observed if apparmor_sock_graft()
is called previously: this sets the 'ctx->label' field by getting
a reference to the current label (later overwritten, without put.)

    static void apparmor_sock_graft(struct sock *sk, ...)
    {
            struct aa_sk_ctx *ctx = SK_CTX(sk);

            if (!ctx->label)
                    ctx->label = aa_get_current_label();
    }

And that is the case on crypto/af_alg.c:af_alg_accept():

    int af_alg_accept(struct sock *sk, struct socket *newsock, ...)
    ...
            struct sock *sk2;
            ...
            sk2 = sk_alloc(...);
            ...
            security_sock_graft(sk2, newsock);
            security_sk_clone(sk, sk2);
    ...

Apparently both calls are done on their own right, especially for
other LSMs, being introduced in 2010/2014, before apparmor socket
mediation in 2017 (see commits [1,2,3,4]).

So, it looks OK there! Let's fix the reference leak in apparmor.

Test-case:
---------

Exercise that code path enough to overflow label reference count.

    $ cat aa-refcnt-af_alg.c
    #include <stdio.h>
    #include <string.h>
    #include <unistd.h>
    #include <sys/socket.h>
    #include <linux/if_alg.h>

    int main() {
            int sockfd;
            struct sockaddr_alg sa;

            /* Setup the crypto API socket */
            sockfd = socket(AF_ALG, SOCK_SEQPACKET, 0);
            if (sockfd < 0) {
                    perror("socket");
                    return 1;
            }

            memset(&sa, 0, sizeof(sa));
            sa.salg_family = AF_ALG;
            strcpy((char *) sa.salg_type, "rng");
            strcpy((char *) sa.salg_name, "stdrng");

            if (bind(sockfd, (struct sockaddr *) &sa, sizeof(sa)) < 0) {
                    perror("bind");
                    return 1;
            }

            /* Accept a "connection" and close it; repeat. */
            while (!close(accept(sockfd, NULL, 0)));

            return 0;
    }

    $ gcc -o aa-refcnt-af_alg aa-refcnt-af_alg.c

    $ ./aa-refcnt-af_alg
    <a few hours later>

    [ 9928.475953] refcount_t overflow at apparmor_sk_clone_security+0x37/0x70 in aa-refcnt-af_alg[1322], uid/euid: 1000/1000
    ...
    [ 9928.507443] RIP: 0010:apparmor_sk_clone_security+0x37/0x70
    ...
    [ 9928.514286]  security_sk_clone+0x33/0x50
    [ 9928.514807]  af_alg_accept+0x81/0x1c0 [af_alg]
    [ 9928.516091]  alg_accept+0x15/0x20 [af_alg]
    [ 9928.516682]  SYSC_accept4+0xff/0x210
    [ 9928.519609]  SyS_accept+0x10/0x20
    [ 9928.520190]  do_syscall_64+0x73/0x130
    [ 9928.520808]  entry_SYSCALL_64_after_hwframe+0x3d/0xa2

Note that other messages may be seen, not just overflow, depending on
the value being incremented by kref_get(); on another run:

    [ 7273.182666] refcount_t: saturated; leaking memory.
    ...
    [ 7273.185789] refcount_t: underflow; use-after-free.

Kprobes:
-------

Using kprobe events to monitor sk -> sk_security -> label -> count (kref):

Original v5.7 (one reference leak every iteration)

 ... (af_alg_accept+0x0/0x1c0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd2
 ... (af_alg_release_parent+0x0/0xd0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd4
 ... (af_alg_accept+0x0/0x1c0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd3
 ... (af_alg_release_parent+0x0/0xd0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd5
 ... (af_alg_accept+0x0/0x1c0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd4
 ... (af_alg_release_parent+0x0/0xd0) label=0xffff8a0f36c25eb0 label_refcnt=0x11fd6

Patched v5.7 (zero reference leak per iteration)

 ... (af_alg_accept+0x0/0x1c0) label=0xffff9ff376c25eb0 label_refcnt=0x593
 ... (af_alg_release_parent+0x0/0xd0) label=0xffff9ff376c25eb0 label_refcnt=0x594
 ... (af_alg_accept+0x0/0x1c0) label=0xffff9ff376c25eb0 label_refcnt=0x593
 ... (af_alg_release_parent+0x0/0xd0) label=0xffff9ff376c25eb0 label_refcnt=0x594
 ... (af_alg_accept+0x0/0x1c0) label=0xffff9ff376c25eb0 label_refcnt=0x593
 ... (af_alg_release_parent+0x0/0xd0) label=0xffff9ff376c25eb0 label_refcnt=0x594

Commits:
-------

[1] commit 507cad355fc9 ("crypto: af_alg - Make sure sk_security is initialized on accept()ed sockets")
[2] commit 4c63f83c2c2e ("crypto: af_alg - properly label AF_ALG socket")
[3] commit 2acce6aa9f65 ("Networking") a.k.a ("crypto: af_alg - Avoid sock_graft call warning)
[4] commit 56974a6fcfef ("apparmor: add base infastructure for socket mediation")

Fixes: 56974a6fcfef ("apparmor: add base infastructure for socket mediation")
Reported-by: Brian Moyles <bmoyles@netflix.com>
Signed-off-by: Mauricio Faria de Oliveira <mfo@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2020-06-07 13:38:56 -07:00
Linus Torvalds
3c0ad98c2e integrity-v5.8
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Merge tag 'integrity-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

Pull integrity updates from Mimi Zohar:
 "The main changes are extending the TPM 2.0 PCR banks with bank
  specific file hashes, calculating the "boot_aggregate" based on other
  TPM PCR banks, using the default IMA hash algorithm, instead of SHA1,
  as the basis for the cache hash table key, and preventing the mprotect
  syscall to circumvent an IMA mmap appraise policy rule.

   - In preparation for extending TPM 2.0 PCR banks with bank specific
     digests, commit 0b6cf6b97b7e ("tpm: pass an array of
     tpm_extend_digest structures to tpm_pcr_extend()") modified
     tpm_pcr_extend(). The original SHA1 file digests were
     padded/truncated, before being extended into the other TPM PCR
     banks. This pull request calculates and extends the TPM PCR banks
     with bank specific file hashes completing the above change.

   - The "boot_aggregate", the first IMA measurement list record, is the
     "trusted boot" link between the pre-boot environment and the
     running OS. With TPM 2.0, the "boot_aggregate" record is not
     limited to being based on the SHA1 TPM PCR bank, but can be
     calculated based on any enabled bank, assuming the hash algorithm
     is also enabled in the kernel.

  Other changes include the following and five other bug fixes/code
  clean up:

   - supporting both a SHA1 and a larger "boot_aggregate" digest in a
     custom template format containing both the the SHA1 ('d') and
     larger digests ('d-ng') fields.

   - Initial hash table key fix, but additional changes would be good"

* tag 'integrity-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  ima: Directly free *entry in ima_alloc_init_template() if digests is NULL
  ima: Call ima_calc_boot_aggregate() in ima_eventdigest_init()
  ima: Directly assign the ima_default_policy pointer to ima_rules
  ima: verify mprotect change is consistent with mmap policy
  evm: Fix possible memory leak in evm_calc_hmac_or_hash()
  ima: Set again build_ima_appraise variable
  ima: Remove redundant policy rule set in add_rules()
  ima: Fix ima digest hash table key calculation
  ima: Use ima_hash_algo for collision detection in the measurement list
  ima: Calculate and extend PCR with digests in ima_template_entry
  ima: Allocate and initialize tfm for each PCR bank
  ima: Switch to dynamically allocated buffer for template digests
  ima: Store template digest directly in ima_template_entry
  ima: Evaluate error in init_ima()
  ima: Switch to ima_hash_algo for boot aggregate
2020-06-06 09:39:05 -07:00
Roberto Sassu
42413b4980 ima: Directly free *entry in ima_alloc_init_template() if digests is NULL
To support multiple template digests, the static array entry->digest has
been replaced with a dynamically allocated array in commit aa724fe18a8a
("ima: Switch to dynamically allocated buffer for template digests"). The
array is allocated in ima_alloc_init_template() and if the returned pointer
is NULL, ima_free_template_entry() is called.

However, (*entry)->template_desc is not yet initialized while it is used by
ima_free_template_entry(). This patch fixes the issue by directly freeing
*entry without calling ima_free_template_entry().

Fixes: aa724fe18a8a ("ima: Switch to dynamically allocated buffer for template digests")
Reported-by: syzbot+223310b454ba6b75974e@syzkaller.appspotmail.com
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2020-06-05 06:04:11 -04:00
Linus Torvalds
886d7de631 Merge branch 'akpm' (patches from Andrew)
Merge yet more updates from Andrew Morton:

 - More MM work. 100ish more to go. Mike Rapoport's "mm: remove
   __ARCH_HAS_5LEVEL_HACK" series should fix the current ppc issue

 - Various other little subsystems

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (127 commits)
  lib/ubsan.c: fix gcc-10 warnings
  tools/testing/selftests/vm: remove duplicate headers
  selftests: vm: pkeys: fix multilib builds for x86
  selftests: vm: pkeys: use the correct page size on powerpc
  selftests/vm/pkeys: override access right definitions on powerpc
  selftests/vm/pkeys: test correct behaviour of pkey-0
  selftests/vm/pkeys: introduce a sub-page allocator
  selftests/vm/pkeys: detect write violation on a mapped access-denied-key page
  selftests/vm/pkeys: associate key on a mapped page and detect write violation
  selftests/vm/pkeys: associate key on a mapped page and detect access violation
  selftests/vm/pkeys: improve checks to determine pkey support
  selftests/vm/pkeys: fix assertion in test_pkey_alloc_exhaust()
  selftests/vm/pkeys: fix number of reserved powerpc pkeys
  selftests/vm/pkeys: introduce powerpc support
  selftests/vm/pkeys: introduce generic pkey abstractions
  selftests: vm: pkeys: use the correct huge page size
  selftests/vm/pkeys: fix alloc_random_pkey() to make it really random
  selftests/vm/pkeys: fix assertion in pkey_disable_set/clear()
  selftests/vm/pkeys: fix pkey_disable_clear()
  selftests: vm: pkeys: add helpers for pkey bits
  ...
2020-06-04 19:18:29 -07:00