From: Theodore Ts'o tytso@mit.edu
[ 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 --- 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 527f53bfe1b1f..16a6c249580e3 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2506,7 +2506,7 @@ 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; @@ -2514,15 +2514,11 @@ 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) @@ -2554,11 +2550,8 @@ 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; }