On Wed, 4 Sep 2024 15:39:37 -0400, Kent Overstreet wrote:
> On Tue, Sep 03, 2024 at 10:13:02AM GMT, Edward Adam Davis wrote:
> > Because the value of m.btree_bitmap_shift is 69 in this case, it cause
> > shift-out-of-bounds in member_to_text.
> >
> > Add a check for btree_bitmap_shift in validate_member, when it bigger than
> > 64
> > return -BCH_ERR_invalid_sb_members.
> > Simultaneously adjust the output mode of btree_bitmap_shift in
> > member_to_text.
> >
> > #syz test
> >
> > diff --git a/fs/bcachefs/sb-members.c b/fs/bcachefs/sb-members.c
> > index 39196f2a4197..85a4245ea6a3 100644
> > --- a/fs/bcachefs/sb-members.c
> > +++ b/fs/bcachefs/sb-members.c
> > @@ -162,6 +162,12 @@ static int validate_member(struct printbuf *err,
> > return -BCH_ERR_invalid_sb_members;
> > }
> >
> > + if (m.btree_bitmap_shift > 64) {
>
> should be >=, no?
Yes, you are right, here should be "if (m.btree_bitmap_shift >= 64)"
>
> > + prt_printf(err, "device %u: too many big bitmap shift (got %u,
> > max 64)",
> > + i, m.btree_bitmap_shift);
> > + return -BCH_ERR_invalid_sb_members;
> > + }
> > +
> > return 0;
> > }
> >
> > @@ -245,8 +251,7 @@ static void member_to_text(struct printbuf *out,
> > prt_printf(out, "(none)");
> > prt_newline(out);
> >
> > - prt_printf(out, "Btree allocated bitmap blocksize:\t");
> > - prt_units_u64(out, 1ULL << m.btree_bitmap_shift);
> > + prt_printf(out, "Btree allocated bitmap shift: %d\t",
> > m.btree_bitmap_shift);
> > prt_newline(out);
> >
> > prt_printf(out, "Btree allocated bitmap:\t");
BR,
Edward
