[PATCH AUTOSEL 6.11 18/76] ext4: filesystems without casefold feature cannot be mounted with siphash

[Sasha Levin]

From: Lizhi Xu <lizhi.xu@xxxxxxxxxxxxx>

[ Upstream commit 985b67cd86392310d9e9326de941c22fc9340eec ]

When mounting the ext4 filesystem, if the default hash version is set to
DX_HASH_SIPHASH but the casefold feature is not set, exit the mounting.

Reported-by: syzbot+340581ba9dceb7e06fb3@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Lizhi Xu <lizhi.xu@xxxxxxxxxxxxx>
Link: https://patch.msgid.link/20240605012335.44086-1-lizhi.xu@xxxxxxxxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/ext4/super.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 93c016b186c07..e8e32cf3e2228 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3583,6 +3583,13 @@ int ext4_feature_set_ok(struct super_block *sb, int readonly)
 			 "mounted without CONFIG_UNICODE");
 		return 0;
 	}
+	if (EXT4_SB(sb)->s_es->s_def_hash_version == DX_HASH_SIPHASH &&
+	    !ext4_has_feature_casefold(sb)) {
+		ext4_msg(sb, KERN_ERR,
+			 "Filesystem without casefold feature cannot be "
+			 "mounted with siphash");
+		return 0;
+	}
 
 	if (readonly)
 		return 1;
-- 
2.43.0