[PATCH 6.6.y] ext4: filesystems without casefold feature cannot be mounted with siphash

[PATCH 6.6.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 71ced0ada9a2..7522bd019639 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3626,6 +3626,13 @@ 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

Re: [PATCH 6.6.y] ext4: filesystems without casefold feature cannot be mounted with siphash

[Greg KH]

On Fri, Jan 24, 2025 at 02:23:17AM +0100, Rajani kantha wrote:
> 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(+)

Why are you submitting this for these 2 kernels?  Why are they required
for them?  You didn't provide any information here at all :(

And what about the fix for this commit?  You forgot that.  Please send a
proper series of backports and make sure you actually tested them.

thanks,

gre gk-h