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

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

[Rajani kantha]

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

[ 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@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: Rajani Kantha <rajanikantha@engineer.com>
---
 fs/ext4/super.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 0b2591c07166..2e9c14e2370f 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3546,6 +3546,13 @@ int ext4_feature_set_ok(struct super_block *sb, int readonly)
 		return 0;
 	}
 #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;
--
2.35.3

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

[Miguel García]

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

commit 985b67cd86392310d9e9326de941c22fc9340eec upstream.

This patch is a backport.

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+9177d065333561cd6fd0@syzkaller.appspotmail.com
Bug: https://syzkaller.appspot.com/bug?extid=9177d065333561cd6fd0
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: Miguel Garcia Roman <miguelgarciaroman8@gmail.com>
(cherry picked from commit 985b67cd86392310d9e9326de941c22fc9340eec)
---
 fs/ext4/super.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 53f1deb049ec..598712a72300 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3546,6 +3545,12 @@ int ext4_feature_set_ok(struct super_block *sb, int readonly)
 		return 0;
 	}
 #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.y] ext4: filesystems without casefold feature cannot be mounted with siphash

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

✅ All tests passed successfully. No issues detected.
No action required from the submitter.

The upstream commit SHA1 provided is correct: 985b67cd86392310d9e9326de941c22fc9340eec

WARNING: Author mismatch between patch and upstream commit:
Backport author: <miguelgarciaroman8@gmail.com>
Commit author: Lizhi Xu<lizhi.xu@windriver.com>

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

Note: The patch differs from the upstream commit:
---
1:  985b67cd86392 ! 1:  18c15fd3e33df ext4: filesystems without casefold feature cannot be mounted with siphash
    @@ Metadata
      ## Commit message ##
         ext4: filesystems without casefold feature cannot be mounted with siphash
     
    +    commit 985b67cd86392310d9e9326de941c22fc9340eec upstream.
    +
    +    This patch is a backport.
    +
         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
    +    Reported-by: syzbot+9177d065333561cd6fd0@syzkaller.appspotmail.com
    +    Bug: https://syzkaller.appspot.com/bug?extid=9177d065333561cd6fd0
         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: Miguel Garcia Roman <miguelgarciaroman8@gmail.com>
    +    (cherry picked from commit 985b67cd86392310d9e9326de941c22fc9340eec)
     
      ## fs/ext4/super.c ##
     @@ fs/ext4/super.c: int ext4_feature_set_ok(struct super_block *sb, int readonly)
    - 			 "mounted without CONFIG_UNICODE");
      		return 0;
      	}
    + #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");
    ++			 "Filesystem without casefold feature cannot be mounted with siphash");
     +		return 0;
     +	}
      
---

Results of testing on various branches:

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

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

[Greg KH]

On Sat, Apr 19, 2025 at 10:40:59AM +0200, Miguel García wrote:
> From: Lizhi Xu <lizhi.xu@windriver.com>
> 
> commit 985b67cd86392310d9e9326de941c22fc9340eec upstream.
> 
> This patch is a backport.

Why?

What about 6.6.y?

And what has been fixed since the last times this has been submitted for
inclusion and rejected?

Please don't ignore past efforts :(

thanks,

greg k-h