On Tue, Jul 30, 2024 at 12:10:19PM GMT, Edward Adam Davis wrote: > syzbot report slab-out-of-bounds in journal_entry_dev_usage_to_text, > it because vstruct_bytes(entry) smaller than sizeof(struct > jset_entry_dev_usage), overflow occurs when calculating the difference in > jset_entry_dev_usage_nr_types(u). > > Reported-by: [email protected] > Closes: https://syzkaller.appspot.com/bug?extid=05d7520be047c9be86e0 > Signed-off-by: Edward Adam Davis <[email protected]> > --- > fs/bcachefs/sb-clean.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/fs/bcachefs/sb-clean.c b/fs/bcachefs/sb-clean.c > index 47f10ab57f40..278e1a25159a 100644 > --- a/fs/bcachefs/sb-clean.c > +++ b/fs/bcachefs/sb-clean.c > @@ -310,6 +310,9 @@ static void bch2_sb_clean_to_text(struct printbuf *out, > struct bch_sb *sb, > !entry->u64s) > continue; > > + if (vstruct_bytes(entry) < sizeof(struct jset_entry_dev_usage)) > + continue;
This is wrong: you haven't checked the entry type and you're assuming it's a dev_usage entry. The check should go in journal_entry_dev_usage_to_text().
