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bcachefs: return err ptr instead of null in read sb clean

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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: syzbot+1cecc37d87c4286e5543@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=1cecc37d87c4286e5543
Signed-off-by: Diogo Jahchan Koike <djahchankoike@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Diogo Jahchan Koike 2024-09-10 18:18:34 -03:00 committed by Kent Overstreet
parent abb43dd677
commit 025c55a4c7
1 changed files with 1 additions and 1 deletions
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2
fs/bcachefs/sb-clean.c
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@ -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),