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Merge patch series "ecryptfs: convert to the new mount API"

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Eric Sandeen <sandeen@redhat.com> says:

This is lightly tested with the kernel tests present in ecryptfs-utils,
but it could certainly use a bit more testing and review, particularly
with invalid mount option sets.

This one is a little unique compared to other filesystems in that I
allocate both an fs context and the *sbi in .init_fs_context; the *sbi
is long-lived, and the context is only present during the initial mount.

Allocating sbi with the filesystem context means we can set options
into it directly, rather than needing to do it after parsing. And it's
particularly simple to do it this way given that there is no remount.

* patches from https://lore.kernel.org/r/20241028143359.605061-1-sandeen@redhat.com:
  ecryptfs: Convert ecryptfs to use the new mount API
  ecryptfs: Factor out mount option validation

Link: https://lore.kernel.org/r/20241028143359.605061-1-sandeen@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Christian Brauner 2024-11-15 11:50:59 +01:00
commit 2cc789654a
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GPG Key ID: 91C61BC06578DCA2
1 changed files with 204 additions and 195 deletions
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399
fs/ecryptfs/main.c
View File

@ -15,10 +15,10 @@
#include <linux/module.h>
#include <linux/namei.h>
#include <linux/skbuff.h>
#include <linux/mount.h>
#include <linux/pagemap.h>
#include <linux/key.h>
#include <linux/parser.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/fs_stack.h>
#include <linux/slab.h>
#include <linux/magic.h>
@ -153,32 +153,30 @@ void ecryptfs_put_lower_file(struct inode *inode)
}
}
enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
ecryptfs_opt_ecryptfs_key_bytes,
ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
ecryptfs_opt_check_dev_ruid,
ecryptfs_opt_err };
enum {
Opt_sig, Opt_ecryptfs_sig, Opt_cipher, Opt_ecryptfs_cipher,
Opt_ecryptfs_key_bytes, Opt_passthrough, Opt_xattr_metadata,
Opt_encrypted_view, Opt_fnek_sig, Opt_fn_cipher,
Opt_fn_cipher_key_bytes, Opt_unlink_sigs, Opt_mount_auth_tok_only,
Opt_check_dev_ruid
};
static const match_table_t tokens = {
{ecryptfs_opt_sig, "sig=%s"},
{ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
{ecryptfs_opt_cipher, "cipher=%s"},
{ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
{ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
{ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
{ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
{ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
{ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
{ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
{ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
{ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
{ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
{ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
{ecryptfs_opt_err, NULL}
static const struct fs_parameter_spec ecryptfs_fs_param_spec[] = {
fsparam_string ("sig", Opt_sig),
fsparam_string ("ecryptfs_sig", Opt_ecryptfs_sig),
fsparam_string ("cipher", Opt_cipher),
fsparam_string ("ecryptfs_cipher", Opt_ecryptfs_cipher),
fsparam_u32 ("ecryptfs_key_bytes", Opt_ecryptfs_key_bytes),
fsparam_flag ("ecryptfs_passthrough", Opt_passthrough),
fsparam_flag ("ecryptfs_xattr_metadata", Opt_xattr_metadata),
fsparam_flag ("ecryptfs_encrypted_view", Opt_encrypted_view),
fsparam_string ("ecryptfs_fnek_sig", Opt_fnek_sig),
fsparam_string ("ecryptfs_fn_cipher", Opt_fn_cipher),
fsparam_u32 ("ecryptfs_fn_key_bytes", Opt_fn_cipher_key_bytes),
fsparam_flag ("ecryptfs_unlink_sigs", Opt_unlink_sigs),
fsparam_flag ("ecryptfs_mount_auth_tok_only", Opt_mount_auth_tok_only),
fsparam_flag ("ecryptfs_check_dev_ruid", Opt_check_dev_ruid),
{}
};
static int ecryptfs_init_global_auth_toks(
@ -219,19 +217,20 @@ static void ecryptfs_init_mount_crypt_stat(
mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
}
struct ecryptfs_fs_context {
/* Mount option status trackers */
bool check_ruid;
bool sig_set;
bool cipher_name_set;
bool cipher_key_bytes_set;
bool fn_cipher_name_set;
bool fn_cipher_key_bytes_set;
};
/**
* ecryptfs_parse_options
* @sbi: The ecryptfs super block
* @options: The options passed to the kernel
* @check_ruid: set to 1 if device uid should be checked against the ruid
*
* Parse mount options:
* debug=N - ecryptfs_verbosity level for debug output
* sig=XXX - description(signature) of the key to use
*
* Returns the dentry object of the lower-level (lower/interposed)
* directory; We want to mount our stackable file system on top of
* that lower directory.
* ecryptfs_parse_param
* @fc: The ecryptfs filesystem context
* @param: The mount parameter to parse
*
* The signature of the key to use must be the description of a key
* already in the keyring. Mounting will fail if the key can not be
@ -239,143 +238,118 @@ static void ecryptfs_init_mount_crypt_stat(
*
* Returns zero on success; non-zero on error
*/
static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
uid_t *check_ruid)
static int ecryptfs_parse_param(
struct fs_context *fc,
struct fs_parameter *param)
{
char *p;
int rc = 0;
int sig_set = 0;
int cipher_name_set = 0;
int fn_cipher_name_set = 0;
int cipher_key_bytes;
int cipher_key_bytes_set = 0;
int fn_cipher_key_bytes;
int fn_cipher_key_bytes_set = 0;
int rc;
int opt;
struct fs_parse_result result;
struct ecryptfs_fs_context *ctx = fc->fs_private;
struct ecryptfs_sb_info *sbi = fc->s_fs_info;
struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
&sbi->mount_crypt_stat;
substring_t args[MAX_OPT_ARGS];
int token;
char *sig_src;
char *cipher_name_src;
char *fn_cipher_name_src;
char *fnek_src;
char *cipher_key_bytes_src;
char *fn_cipher_key_bytes_src;
u8 cipher_code;
*check_ruid = 0;
opt = fs_parse(fc, ecryptfs_fs_param_spec, param, &result);
if (opt < 0)
return opt;
if (!options) {
rc = -EINVAL;
goto out;
}
ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
while ((p = strsep(&options, ",")) != NULL) {
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case ecryptfs_opt_sig:
case ecryptfs_opt_ecryptfs_sig:
sig_src = args[0].from;
rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
sig_src, 0);
if (rc) {
printk(KERN_ERR "Error attempting to register "
"global sig; rc = [%d]\n", rc);
goto out;
}
sig_set = 1;
break;
case ecryptfs_opt_cipher:
case ecryptfs_opt_ecryptfs_cipher:
cipher_name_src = args[0].from;
strscpy(mount_crypt_stat->global_default_cipher_name,
cipher_name_src);
cipher_name_set = 1;
break;
case ecryptfs_opt_ecryptfs_key_bytes:
cipher_key_bytes_src = args[0].from;
cipher_key_bytes =
(int)simple_strtol(cipher_key_bytes_src,
&cipher_key_bytes_src, 0);
mount_crypt_stat->global_default_cipher_key_size =
cipher_key_bytes;
cipher_key_bytes_set = 1;
break;
case ecryptfs_opt_passthrough:
mount_crypt_stat->flags |=
ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
break;
case ecryptfs_opt_xattr_metadata:
mount_crypt_stat->flags |=
ECRYPTFS_XATTR_METADATA_ENABLED;
break;
case ecryptfs_opt_encrypted_view:
mount_crypt_stat->flags |=
ECRYPTFS_XATTR_METADATA_ENABLED;
mount_crypt_stat->flags |=
ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
break;
case ecryptfs_opt_fnek_sig:
fnek_src = args[0].from;
strscpy(mount_crypt_stat->global_default_fnek_sig,
fnek_src);
rc = ecryptfs_add_global_auth_tok(
mount_crypt_stat,
mount_crypt_stat->global_default_fnek_sig,
ECRYPTFS_AUTH_TOK_FNEK);
if (rc) {
printk(KERN_ERR "Error attempting to register "
"global fnek sig [%s]; rc = [%d]\n",
mount_crypt_stat->global_default_fnek_sig,
rc);
goto out;
}
mount_crypt_stat->flags |=
(ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
| ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
break;
case ecryptfs_opt_fn_cipher:
fn_cipher_name_src = args[0].from;
strscpy(mount_crypt_stat->global_default_fn_cipher_name,
fn_cipher_name_src);
fn_cipher_name_set = 1;
break;
case ecryptfs_opt_fn_cipher_key_bytes:
fn_cipher_key_bytes_src = args[0].from;
fn_cipher_key_bytes =
(int)simple_strtol(fn_cipher_key_bytes_src,
&fn_cipher_key_bytes_src, 0);
mount_crypt_stat->global_default_fn_cipher_key_bytes =
fn_cipher_key_bytes;
fn_cipher_key_bytes_set = 1;
break;
case ecryptfs_opt_unlink_sigs:
mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
break;
case ecryptfs_opt_mount_auth_tok_only:
mount_crypt_stat->flags |=
ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
break;
case ecryptfs_opt_check_dev_ruid:
*check_ruid = 1;
break;
case ecryptfs_opt_err:
default:
printk(KERN_WARNING
"%s: eCryptfs: unrecognized option [%s]\n",
__func__, p);
switch (opt) {
case Opt_sig:
case Opt_ecryptfs_sig:
rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
param->string, 0);
if (rc) {
printk(KERN_ERR "Error attempting to register "
"global sig; rc = [%d]\n", rc);
return rc;
}
ctx->sig_set = 1;
break;
case Opt_cipher:
case Opt_ecryptfs_cipher:
strscpy(mount_crypt_stat->global_default_cipher_name,
param->string);
ctx->cipher_name_set = 1;
break;
case Opt_ecryptfs_key_bytes:
mount_crypt_stat->global_default_cipher_key_size =
result.uint_32;
ctx->cipher_key_bytes_set = 1;
break;
case Opt_passthrough:
mount_crypt_stat->flags |=
ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
break;
case Opt_xattr_metadata:
mount_crypt_stat->flags |= ECRYPTFS_XATTR_METADATA_ENABLED;
break;
case Opt_encrypted_view:
mount_crypt_stat->flags |= ECRYPTFS_XATTR_METADATA_ENABLED;
mount_crypt_stat->flags |= ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
break;
case Opt_fnek_sig:
strscpy(mount_crypt_stat->global_default_fnek_sig,
param->string);
rc = ecryptfs_add_global_auth_tok(
mount_crypt_stat,
mount_crypt_stat->global_default_fnek_sig,
ECRYPTFS_AUTH_TOK_FNEK);
if (rc) {
printk(KERN_ERR "Error attempting to register "
"global fnek sig [%s]; rc = [%d]\n",
mount_crypt_stat->global_default_fnek_sig, rc);
return rc;
}
mount_crypt_stat->flags |=
(ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
| ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
break;
case Opt_fn_cipher:
strscpy(mount_crypt_stat->global_default_fn_cipher_name,
param->string);
ctx->fn_cipher_name_set = 1;
break;
case Opt_fn_cipher_key_bytes:
mount_crypt_stat->global_default_fn_cipher_key_bytes =
result.uint_32;
ctx->fn_cipher_key_bytes_set = 1;
break;
case Opt_unlink_sigs:
mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
break;
case Opt_mount_auth_tok_only:
mount_crypt_stat->flags |= ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
break;
case Opt_check_dev_ruid:
ctx->check_ruid = 1;
break;
default:
return -EINVAL;
}
if (!sig_set) {
return 0;
}
static int ecryptfs_validate_options(struct fs_context *fc)
{
int rc = 0;
u8 cipher_code;
struct ecryptfs_fs_context *ctx = fc->fs_private;
struct ecryptfs_sb_info *sbi = fc->s_fs_info;
struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
mount_crypt_stat = &sbi->mount_crypt_stat;
if (!ctx->sig_set) {
rc = -EINVAL;
ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
"auth tok signature as a mount "
"parameter; see the eCryptfs README\n");
goto out;
}
if (!cipher_name_set) {
if (!ctx->cipher_name_set) {
int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
@ -383,13 +357,13 @@ static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
ECRYPTFS_DEFAULT_CIPHER);
}
if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
&& !fn_cipher_name_set)
&& !ctx->fn_cipher_name_set)
strcpy(mount_crypt_stat->global_default_fn_cipher_name,
mount_crypt_stat->global_default_cipher_name);
if (!cipher_key_bytes_set)
if (!ctx->cipher_key_bytes_set)
mount_crypt_stat->global_default_cipher_key_size = 0;
if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
&& !fn_cipher_key_bytes_set)
&& !ctx->fn_cipher_key_bytes_set)
mount_crypt_stat->global_default_fn_cipher_key_bytes =
mount_crypt_stat->global_default_cipher_key_size;
@ -453,45 +427,35 @@ struct kmem_cache *ecryptfs_sb_info_cache;
static struct file_system_type ecryptfs_fs_type;
/*
* ecryptfs_mount
* @fs_type: The filesystem type that the superblock should belong to
* @flags: The flags associated with the mount
* @dev_name: The path to mount over
* @raw_data: The options passed into the kernel
* ecryptfs_get_tree
* @fc: The filesystem context
*/
static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
const char *dev_name, void *raw_data)
static int ecryptfs_get_tree(struct fs_context *fc)
{
struct super_block *s;
struct ecryptfs_sb_info *sbi;
struct ecryptfs_fs_context *ctx = fc->fs_private;
struct ecryptfs_sb_info *sbi = fc->s_fs_info;
struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
struct ecryptfs_dentry_info *root_info;
const char *err = "Getting sb failed";
struct inode *inode;
struct path path;
uid_t check_ruid;
int rc;
sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
if (!sbi) {
rc = -ENOMEM;
goto out;
}
if (!dev_name) {
if (!fc->source) {
rc = -EINVAL;
err = "Device name cannot be null";
goto out;
}
rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
mount_crypt_stat = &sbi->mount_crypt_stat;
rc = ecryptfs_validate_options(fc);
if (rc) {
err = "Error parsing options";
err = "Error validationg options";
goto out;
}
mount_crypt_stat = &sbi->mount_crypt_stat;
s = sget(fs_type, NULL, set_anon_super, flags, NULL);
s = sget_fc(fc, NULL, set_anon_super_fc);
if (IS_ERR(s)) {
rc = PTR_ERR(s);
goto out;
@ -510,7 +474,7 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags
s->s_d_op = &ecryptfs_dops;
err = "Reading sb failed";
rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
rc = kern_path(fc->source, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
if (rc) {
ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
goto out1;
@ -529,7 +493,8 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags
goto out_free;
}
if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
if (ctx->check_ruid &&
!uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
rc = -EPERM;
printk(KERN_ERR "Mount of device (uid: %d) not owned by "
"requested user (uid: %d)\n",
@ -544,7 +509,7 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags
* Set the POSIX ACL flag based on whether they're enabled in the lower
* mount.
*/
s->s_flags = flags & ~SB_POSIXACL;
s->s_flags = fc->sb_flags & ~SB_POSIXACL;
s->s_flags |= path.dentry->d_sb->s_flags & SB_POSIXACL;
/**
@ -587,19 +552,19 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags
root_info->lower_path = path;
s->s_flags |= SB_ACTIVE;
return dget(s->s_root);
fc->root = dget(s->s_root);
return 0;
out_free:
path_put(&path);
out1:
deactivate_locked_super(s);
out:
if (sbi) {
if (sbi)
ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
kmem_cache_free(ecryptfs_sb_info_cache, sbi);
}
printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
return ERR_PTR(rc);
return rc;
}
/**
@ -618,10 +583,54 @@ static void ecryptfs_kill_block_super(struct super_block *sb)
kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
}
static void ecryptfs_free_fc(struct fs_context *fc)
{
struct ecryptfs_fs_context *ctx = fc->fs_private;
struct ecryptfs_sb_info *sbi = fc->s_fs_info;
kfree(ctx);
if (sbi) {
ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
kmem_cache_free(ecryptfs_sb_info_cache, sbi);
}
}
static const struct fs_context_operations ecryptfs_context_ops = {
.free = ecryptfs_free_fc,
.parse_param = ecryptfs_parse_param,
.get_tree = ecryptfs_get_tree,
.reconfigure = NULL,
};
static int ecryptfs_init_fs_context(struct fs_context *fc)
{
struct ecryptfs_fs_context *ctx;
struct ecryptfs_sb_info *sbi = NULL;
ctx = kzalloc(sizeof(struct ecryptfs_fs_context), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
if (!sbi) {
kfree(ctx);
ctx = NULL;
return -ENOMEM;
}
ecryptfs_init_mount_crypt_stat(&sbi->mount_crypt_stat);
fc->fs_private = ctx;
fc->s_fs_info = sbi;
fc->ops = &ecryptfs_context_ops;
return 0;
}
static struct file_system_type ecryptfs_fs_type = {
.owner = THIS_MODULE,
.name = "ecryptfs",
.mount = ecryptfs_mount,
.init_fs_context = ecryptfs_init_fs_context,
.parameters = ecryptfs_fs_param_spec,
.kill_sb = ecryptfs_kill_block_super,
.fs_flags = 0
};