commit-graph: verify contents match checksum

[thirdparty/git.git] / commit-graph.c

diff --git a/commit-graph.c b/commit-graph.c
index 3ac28b5eb5c63fd081424fa8354ca15d3dc58cc8..aca9e5e2dc994fdd4febce79982efd323f6558db 100644 (file)
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -833,6 +833,7 @@ void write_commit_graph(const char *obj_dir,
        oids.nr = 0;
 }
 
+#define VERIFY_COMMIT_GRAPH_ERROR_HASH 2
 static int verify_commit_graph_error;
 
 static void graph_report(const char *fmt, ...)
@@ -852,8 +853,10 @@ static void graph_report(const char *fmt, ...)
 int verify_commit_graph(struct repository *r, struct commit_graph *g)
 {
        uint32_t i, cur_fanout_pos = 0;
-       struct object_id prev_oid, cur_oid;
+       struct object_id prev_oid, cur_oid, checksum;
        int generation_zero = 0;
+       struct hashfile *f;
+       int devnull;
 
        if (!g) {
                graph_report("no commit-graph file loaded");
@@ -872,6 +875,15 @@ int verify_commit_graph(struct repository *r, struct commit_graph *g)
        if (verify_commit_graph_error)
                return verify_commit_graph_error;
 
+       devnull = open("/dev/null", O_WRONLY);
+       f = hashfd(devnull, NULL);
+       hashwrite(f, g->data, g->data_len - g->hash_len);
+       finalize_hashfile(f, checksum.hash, CSUM_CLOSE);
+       if (hashcmp(checksum.hash, g->data + g->data_len - g->hash_len)) {
+               graph_report(_("the commit-graph file has incorrect checksum and is likely corrupt"));
+               verify_commit_graph_error = VERIFY_COMMIT_GRAPH_ERROR_HASH;
+       }
+
        for (i = 0; i < g->num_commits; i++) {
                struct commit *graph_commit;
 
@@ -909,7 +921,7 @@ int verify_commit_graph(struct repository *r, struct commit_graph *g)
                cur_fanout_pos++;
        }
 
-       if (verify_commit_graph_error)
+       if (verify_commit_graph_error & ~VERIFY_COMMIT_GRAPH_ERROR_HASH)
                return verify_commit_graph_error;
 
        for (i = 0; i < g->num_commits; i++) {