On Fri, Feb 28, 2020 at 05:24:49PM +0100, Damien Robert wrote:
> When verifying a midx index with 0 objects, the
> m->num_objects - 1
> overflows to 4294967295.
>
> Fix this.
Makes sense. Such a midx shouldn't be generated in the first place, but
we should handle it robustly if we do see one.
> diff --git a/midx.c b/midx.c
> index 37ec28623a..6ffe013089 100644
> --- a/midx.c
> +++ b/midx.c
> @@ -1127,7 +1127,7 @@ int verify_midx_file(struct repository *r, const char *object_dir, unsigned flag
> if (flags & MIDX_PROGRESS)
> progress = start_sparse_progress(_("Verifying OID order in multi-pack-index"),
> m->num_objects - 1);
> - for (i = 0; i < m->num_objects - 1; i++) {
> + for (i = 0; i + 1 < m->num_objects; i++) {
> struct object_id oid1, oid2;
>
> nth_midxed_object_oid(&oid1, m, i);
[...] nth_midxed_object_oid(&oid2, m, i + 1);
Perhaps it would be simpler as:
for (i = 1; i < m->num_objects; i++) {
...
nth_midxed_object_oid(&oid1, m, i - 1);
nth_midxed_object_oid(&oid2, m, i);
...
}
Though I almost wonder if we should be catching "m->num_objects == 0"
early and declaring the midx to be bogus (it's not _technically_ wrong,
but I'd have to suspect a bug in anything that generated a 0-object midx
file).
-Peff
