On Tue, Aug 20, 2024 at 03:11:45PM GMT, Lizhi Xu wrote: > When journal v2 entry nr overflow, it will cause the value of ja->nr to > be incorrect, this will result in the allocated memory to ja->buckets > being too small, leading to out of bounds access in bch2_dev_journal_init. > > Reported-by: [email protected] > Signed-off-by: Lizhi Xu <[email protected]> > --- > fs/bcachefs/journal_sb.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/fs/bcachefs/journal_sb.c b/fs/bcachefs/journal_sb.c > index db80e506e3ab..db2b2100e4e5 100644 > --- a/fs/bcachefs/journal_sb.c > +++ b/fs/bcachefs/journal_sb.c > @@ -119,6 +119,11 @@ static int bch2_sb_journal_v2_validate(struct bch_sb > *sb, struct bch_sb_field *f > for (i = 0; i < nr; i++) { > b[i].start = le64_to_cpu(journal->d[i].start); > b[i].end = b[i].start + le64_to_cpu(journal->d[i].nr); > + if (le64_to_cpu(journal->d[i].nr) > UINT_MAX) { > + prt_printf(err, "journal v2 entry d[%u].nr %llu > overflow\n", > + i, le64_to_cpu(journal->d[i].nr)); > + goto err; > + }
no, you need to sum up _all_ the entries and verify the total doesn't overflow UINT_MAX
