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| author | Gabriel Krisman Bertazi <krisman@suse.de> | 2024-02-21 12:14:03 -0500 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2024-03-26 18:17:59 -0400 |
| commit | db6be34474de4acc683fb3b40b0224f17206eb8f (patch) | |
| tree | 27975c8abe6a968660f1446eac4a556ec48a21be /include | |
| parent | fe7670ede9aa69cd300a0daa584d493141efdc18 (diff) | |
| download | linux-stable-db6be34474de4acc683fb3b40b0224f17206eb8f.tar.gz linux-stable-db6be34474de4acc683fb3b40b0224f17206eb8f.tar.bz2 linux-stable-db6be34474de4acc683fb3b40b0224f17206eb8f.zip | |
ovl: Always reject mounting over case-insensitive directories
[ Upstream commit 2824083db76cb9d4b7910607b367e93b02912865 ]
overlayfs relies on the filesystem setting DCACHE_OP_HASH or
DCACHE_OP_COMPARE to reject mounting over case-insensitive directories.
Since commit bb9cd9106b22 ("fscrypt: Have filesystems handle their
d_ops"), we set ->d_op through a hook in ->d_lookup, which
means the root dentry won't have them, causing the mount to accidentally
succeed.
In v6.7-rc7, the following sequence will succeed to mount, but any
dentry other than the root dentry will be a "weird" dentry to ovl and
fail with EREMOTE.
mkfs.ext4 -O casefold lower.img
mount -O loop lower.img lower
mount -t overlay -o lowerdir=lower,upperdir=upper,workdir=work ovl /mnt
Mounting on a subdirectory fails, as expected, because DCACHE_OP_HASH
and DCACHE_OP_COMPARE are properly set by ->lookup.
Fix by explicitly rejecting superblocks that allow case-insensitive
dentries. Yes, this will be solved when we move d_op configuration back
to ->s_d_op. Yet, we better have an explicit fix to avoid messing up
again.
While there, re-sort the entries to have more descriptive error messages
first.
Fixes: bb9cd9106b22 ("fscrypt: Have filesystems handle their d_ops")
Acked-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20240221171412.10710-2-krisman@suse.de
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/fs.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index 7f659c26794b..98c718b0fe53 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3205,6 +3205,15 @@ extern int generic_check_addressable(unsigned, u64); extern void generic_set_encrypted_ci_d_ops(struct dentry *dentry); +static inline bool sb_has_encoding(const struct super_block *sb) +{ +#if IS_ENABLED(CONFIG_UNICODE) + return !!sb->s_encoding; +#else + return false; +#endif +} + int may_setattr(struct mnt_idmap *idmap, struct inode *inode, unsigned int ia_valid); int setattr_prepare(struct mnt_idmap *, struct dentry *, struct iattr *); |