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author | Gabriel Krisman Bertazi <krisman@suse.de> | 2024-02-21 12:14:03 -0500 |
---|---|---|
committer | Gabriel Krisman Bertazi <krisman@suse.de> | 2024-02-27 16:55:34 -0500 |
commit | 2824083db76cb9d4b7910607b367e93b02912865 (patch) | |
tree | fd26e1664e0ab9123ddce62ffc27220445c88281 /include/linux/fs.h | |
parent | 0906fbb2f7ad6ae4b1bee8777bf83171a12c10b0 (diff) | |
download | linux-2824083db76cb9d4b7910607b367e93b02912865.tar.gz |
ovl: Always reject mounting over case-insensitive directories
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>
Diffstat (limited to 'include/linux/fs.h')
-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 e6ba0cc6f2eeea..a0eb8b5759a6fe 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3282,6 +3282,15 @@ 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 *); |