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ecryptfs: Factor out mount option validation

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Under the new mount API, mount options are parsed one at a time.
Any validation that examines multiple options must be done after parsing
is complete, so factor out a ecryptfs_validate_options() which can be
called separately.

To facilitate this, temporarily move the local variables that tracked
whether various options have been set in the parsing function, into the
ecryptfs_mount_crypt_stat structure so that they can be examined later.

These will be moved to a more ephemeral struct in the mount api conversion
patch to follow.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Link: https://lore.kernel.org/r/20241028143359.605061-2-sandeen@redhat.com
Acked-by: Tyler Hicks <code@tyhicks.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Eric Sandeen 2024-10-28 09:32:38 -05:00 committed by Christian Brauner
parent b4201b51d9
commit 56bd06c264
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
2 changed files with 38 additions and 24 deletions
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7
fs/ecryptfs/ecryptfs_kernel.h
View File

@ -343,6 +343,13 @@ struct ecryptfs_mount_crypt_stat {
unsigned char global_default_fn_cipher_name[
ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
char global_default_fnek_sig[ECRYPTFS_SIG_SIZE_HEX + 1];
/* 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;
};
/* superblock private data. */

55
fs/ecryptfs/main.c
View File

@ -239,18 +239,12 @@ 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_options(struct ecryptfs_sb_info *sbi, char *options)
{
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;
struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
&sbi->mount_crypt_stat;
substring_t args[MAX_OPT_ARGS];
@ -261,9 +255,6 @@ static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
char *fnek_src;
char *cipher_key_bytes_src;
char *fn_cipher_key_bytes_src;
u8 cipher_code;
*check_ruid = 0;
if (!options) {
rc = -EINVAL;
@ -285,14 +276,14 @@ static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
"global sig; rc = [%d]\n", rc);
goto out;
}
sig_set = 1;
mount_crypt_stat->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;
mount_crypt_stat->cipher_name_set = 1;
break;
case ecryptfs_opt_ecryptfs_key_bytes:
cipher_key_bytes_src = args[0].from;
@ -301,7 +292,7 @@ static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
&cipher_key_bytes_src, 0);
mount_crypt_stat->global_default_cipher_key_size =
cipher_key_bytes;
cipher_key_bytes_set = 1;
mount_crypt_stat->cipher_key_bytes_set = 1;
break;
case ecryptfs_opt_passthrough:
mount_crypt_stat->flags |=
@ -340,7 +331,7 @@ static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
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;
mount_crypt_stat->fn_cipher_name_set = 1;
break;
case ecryptfs_opt_fn_cipher_key_bytes:
fn_cipher_key_bytes_src = args[0].from;
@ -349,7 +340,7 @@ static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
&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;
mount_crypt_stat->fn_cipher_key_bytes_set = 1;
break;
case ecryptfs_opt_unlink_sigs:
mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
@ -359,7 +350,7 @@ static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
break;
case ecryptfs_opt_check_dev_ruid:
*check_ruid = 1;
mount_crypt_stat->check_ruid = 1;
break;
case ecryptfs_opt_err:
default:
@ -368,14 +359,25 @@ static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
__func__, p);
}
}
if (!sig_set) {
out:
return rc;
}
static int ecryptfs_validate_options(
struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
{
int rc = 0;
u8 cipher_code;
if (!mount_crypt_stat->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 (!mount_crypt_stat->cipher_name_set) {
int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
@ -383,13 +385,13 @@ 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)
&& !mount_crypt_stat->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 (!mount_crypt_stat->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)
&& !mount_crypt_stat->fn_cipher_key_bytes_set)
mount_crypt_stat->global_default_fn_cipher_key_bytes =
mount_crypt_stat->global_default_cipher_key_size;
@ -469,7 +471,6 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags
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);
@ -484,12 +485,17 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags
goto out;
}
rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
rc = ecryptfs_parse_options(sbi, raw_data);
if (rc) {
err = "Error parsing options";
goto out;
}
mount_crypt_stat = &sbi->mount_crypt_stat;
rc = ecryptfs_validate_options(mount_crypt_stat);
if (rc) {
err = "Error validationg options";
goto out;
}
s = sget(fs_type, NULL, set_anon_super, flags, NULL);
if (IS_ERR(s)) {
@ -529,7 +535,8 @@ 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 (mount_crypt_stat->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",