This is a note to let you know that I've just added the patch titled ext4: filesystems without casefold feature cannot be mounted with siphash to the 6.11-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ext4-filesystems-without-casefold-feature-cannot-be-.patch and it can be found in the queue-6.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit cdab430227e0f6cf201ab478053b27113923d6fe Author: Lizhi Xu <lizhi.xu@xxxxxxxxxxxxx> Date: Wed Jun 5 09:23:35 2024 +0800 ext4: filesystems without casefold feature cannot be mounted with siphash [ 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> diff --git a/fs/ext4/super.c b/fs/ext4/super.c index cd3328b031534..4b6609f44fdc4 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;