syzbot reported a null-ptr-deref in bch2_fs_start. [0] When a sb is marked clear but doesn't have a clean section bch2_read_superblock_clean returns NULL which PTR_ERR_OR_ZERO lets through, eventually leading to a null ptr dereference down the line. Adjust read sb clean to return an ERR_PTR indicating the invalid clean section.
[0] https://syzkaller.appspot.com/bug?extid=1cecc37d87c4286e5543 Reported-by: [email protected] Closes: https://syzkaller.appspot.com/bug?extid=1cecc37d87c4286e5543 Signed-off-by: Diogo Jahchan Koike <[email protected]> --- fs/bcachefs/sb-clean.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/bcachefs/sb-clean.c b/fs/bcachefs/sb-clean.c index c57d42bb8d1b..025848a9c4c0 100644 --- a/fs/bcachefs/sb-clean.c +++ b/fs/bcachefs/sb-clean.c @@ -155,7 +155,7 @@ struct bch_sb_field_clean *bch2_read_superblock_clean(struct bch_fs *c) SET_BCH_SB_CLEAN(c->disk_sb.sb, false); c->sb.clean = false; mutex_unlock(&c->sb_lock); - return NULL; + return ERR_PTR(-BCH_ERR_invalid_sb_clean); } clean = kmemdup(sb_clean, vstruct_bytes(&sb_clean->field), -- 2.43.0
