From: Taylor Blau <me@ttaylorr.com>
Date: Wed, 12 Jul 2023 23:38:13 +0000 (-0400)
Subject: commit-graph.c: prevent overflow in `merge_commit_graph()`
X-Git-Tag: v2.42.0-rc0~39^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d76e0a744d3a8c1713f0e913325cab7da92f01ef;p=thirdparty%2Fgit.git

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

When merging two commit graphs, ensure that we don't attempt to merge
two graphs which, when combined, have more total commits than the 32-bit
unsigned maximum.

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 d9795e3aa4..8333ce8e04 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -2179,6 +2179,11 @@ static void merge_commit_graph(struct write_commit_graph_context *ctx,
 	uint32_t i;
 	uint32_t offset = g->num_commits_in_base;
 
+	if (unsigned_add_overflows(ctx->commits.nr, g->num_commits))
+		die(_("cannot merge graph %s, too many commits: %"PRIuMAX),
+		    oid_to_hex(&g->oid),
+		    (uintmax_t)st_add(ctx->commits.nr, g->num_commits));
+
 	ALLOC_GROW(ctx->commits.list, ctx->commits.nr + g->num_commits, ctx->commits.alloc);
 
 	for (i = 0; i < g->num_commits; i++) {