[PATCH 6.1] ext4: filesystems without casefold feature cannot be mounted with siphash

[PATCH 6.1] ext4: filesystems without casefold feature cannot be mounted with siphash

[vgiraud.opensource]

From: Lizhi Xu <lizhi.xu@windriver.com>

commit 985b67cd86392310d9e9326de941c22fc9340eec upstream.

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@syzkaller.appspotmail.com
Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
Link: https://patch.msgid.link/20240605012335.44086-1-lizhi.xu@windriver.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Bruno VERNAY <bruno.vernay@se.com>
Signed-off-by: Victor Giraud <vgiraud.opensource@witekio.com>
---
 fs/ext4/super.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 53f1deb049ec..ca1d9a36aba2 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3547,6 +3547,14 @@ int ext4_feature_set_ok(struct super_block *sb, int readonly)
 	}
 #endif
 
+	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;
 
-- 
2.34.1

Re: [PATCH 6.1] ext4: filesystems without casefold feature cannot be mounted with siphash

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

The upstream commit SHA1 provided is correct: 985b67cd86392310d9e9326de941c22fc9340eec

WARNING: Author mismatch between patch and upstream commit:
Backport author: vgiraud.opensource@witekio.com
Commit author: Lizhi Xu<lizhi.xu@windriver.com>


Status in newer kernel trees:
6.13.y | Present (exact SHA1)
6.12.y | Present (exact SHA1)
6.6.y | Not found
6.1.y | Not found

Note: The patch differs from the upstream commit:
---
1:  985b67cd86392 < -:  ------------- ext4: filesystems without casefold feature cannot be mounted with siphash
-:  ------------- > 1:  ade03c938cb51 ext4: filesystems without casefold feature cannot be mounted with siphash
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.1.y        |  Success    |  Failed    |

Build Errors:
Build error for stable/linux-6.1.y:
    ssh: connect to host 192.168.1.58 port 22: No route to host

Re: [PATCH 6.1] ext4: filesystems without casefold feature cannot be mounted with siphash

[Vasiliy Kovalev]

A backport requires the fix commit a2187431c395 ("ext4: fix error message when rejecting the default hash").
and a prerequisite commit db9345d9e6f0 ("ext4: factor out ext4_hash_info_init()")

See the patch series: https://lore.kernel.org/all/20241118102050.16077-1-kovalev@altlinux.org/t/#u

--
Thanks,
Vasiliy