From: Theodore Ts'o <tytso@mit.edu> stable inclusion from stable-v6.6.114 commit 01829af7656b56d83682b3491265d583d502e502 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ID6BW2 CVE: CVE-2025-40198 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 8ecb790ea8c3fc69e77bace57f14cf0d7c177bd8 ] Unlike other strings in the ext4 superblock, we rely on tune2fs to make sure s_mount_opts is NUL terminated. Harden parse_apply_sb_mount_options() by treating s_mount_opts as a potential __nonstring. Cc: stable@vger.kernel.org Fixes: 8b67f04ab9de ("ext4: Add mount options in superblock") Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Message-ID: <20250916-tune2fs-v2-1-d594dc7486f0@mit.edu> Signed-off-by: Theodore Ts'o <tytso@mit.edu> [ added sizeof() third argument to strscpy_pad() ] Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yongjian Sun <sunyongjian1@huawei.com> --- fs/ext4/super.c | 17 +++++------------ 1 file changed, 5 insertions(+), 12 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index f68fbe8c82ff..3a3baff2d08f 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2592,7 +2592,7 @@ static int parse_apply_sb_mount_options(struct super_block *sb, struct ext4_fs_context *m_ctx) { struct ext4_sb_info *sbi = EXT4_SB(sb); - char *s_mount_opts = NULL; + char s_mount_opts[65]; struct ext4_fs_context *s_ctx = NULL; struct fs_context *fc = NULL; int ret = -ENOMEM; @@ -2600,15 +2600,11 @@ static int parse_apply_sb_mount_options(struct super_block *sb, if (!sbi->s_es->s_mount_opts[0]) return 0; - s_mount_opts = kstrndup(sbi->s_es->s_mount_opts, - sizeof(sbi->s_es->s_mount_opts), - GFP_KERNEL); - if (!s_mount_opts) - return ret; + strscpy_pad(s_mount_opts, sbi->s_es->s_mount_opts, sizeof(s_mount_opts)); fc = kzalloc(sizeof(struct fs_context), GFP_KERNEL); if (!fc) - goto out_free; + return -ENOMEM; s_ctx = kzalloc(sizeof(struct ext4_fs_context), GFP_KERNEL); if (!s_ctx) @@ -2640,11 +2636,8 @@ static int parse_apply_sb_mount_options(struct super_block *sb, ret = 0; out_free: - if (fc) { - ext4_fc_free(fc); - kfree(fc); - } - kfree(s_mount_opts); + ext4_fc_free(fc); + kfree(fc); return ret; } -- 2.39.2