[PATCH 6.6 053/322] ecryptfs: Reject casefold directory inodes

Greg Kroah-Hartman
2024-02-03T04:11:55Z

From: Gabriel Krisman Bertazi <krisman@suse.de>

[ Upstream commit cd72c7ef5fed44272272a105b1da22810c91be69 ]

Even though it seems to be able to resolve some names of
case-insensitive directories, the lack of d_hash and d_compare means we
end up with a broken state in the d_cache. Considering it was never a
goal to support these two together, and we are preparing to use
d_revalidate in case-insensitive filesystems, which would make the
combination even more broken, reject any attempt to get a casefolded
inode from ecryptfs.

Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ecryptfs/inode.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 5ab4b87888a7..795e9fe2f721 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -78,6 +78,14 @@ static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,

if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
return ERR_PTR(-EXDEV);
+
+ /* Reject dealing with casefold directories. */
+ if (IS_CASEFOLDED(lower_inode)) {
+ pr_err_ratelimited("%s: Can't handle casefolded directory.\n",
+ __func__);
+ return ERR_PTR(-EREMOTE);
+ }
+
if (!igrab(lower_inode))
return ERR_PTR(-ESTALE);
inode = iget5_locked(sb, (unsigned long)lower_inode,
--
2.43.0