From: Gabriel Krisman Bertazi <krisman@suse.de>
Date: Fri, 11 Aug 2023 18:38:12 +0000 (-0400)
Subject: ecryptfs: Reject casefold directory inodes
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=cd72c7ef5fed44272272a105b1da22810c91be69;p=users%2Fjedix%2Flinux-maple.git

ecryptfs: Reject casefold directory inodes

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>
---

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index a25dd3d20008..00d8de9a448d 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,