commit-graph.c: prevent overflow in `verify_commit_graph()`

In a similar spirit as previous commits, ensure that we don't overflow
when trying to read an OID out of an existing commit-graph during
verification.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/commit-graph.c b/commit-graph.c
index 54697e7a4d51929a7f07fd04546f760b08ac0685..dc5bcfe05b3abb55ad1479d84c8bf9c182e98e14 100644 (file)
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -2585,7 +2585,7 @@ int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
        for (i = 0; i < g->num_commits; i++) {
                struct commit *graph_commit;
 
-               oidread(&cur_oid, g->chunk_oid_lookup + g->hash_len * i);
+               oidread(&cur_oid, g->chunk_oid_lookup + st_mult(g->hash_len, i));
 
                if (i && oidcmp(&prev_oid, &cur_oid) >= 0)
                        graph_report(_("commit-graph has incorrect OID order: %s then %s"),
@@ -2633,7 +2633,7 @@ int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags)
                timestamp_t generation;
 
                display_progress(progress, i + 1);
-               oidread(&cur_oid, g->chunk_oid_lookup + g->hash_len * i);
+               oidread(&cur_oid, g->chunk_oid_lookup + st_mult(g->hash_len, i));
 
                graph_commit = lookup_commit(r, &cur_oid);
                odb_commit = (struct commit *)create_object(r, &cur_oid, alloc_commit_node(r));