commit-graph: fix buffer read-overflow
[gitweb.git] / commit-graph.c
index 40c855f1855595fbf5b285008d3c829e6a2f41eb..359e782deed65ec5478c59b1f439adb90aabf124 100644 (file)
@@ -84,16 +84,10 @@ static int commit_graph_compatible(struct repository *r)
 struct commit_graph *load_commit_graph_one(const char *graph_file)
 {
        void *graph_map;
-       const unsigned char *data, *chunk_lookup;
        size_t graph_size;
        struct stat st;
-       uint32_t i;
-       struct commit_graph *graph;
+       struct commit_graph *ret;
        int fd = git_open(graph_file);
-       uint64_t last_chunk_offset;
-       uint32_t last_chunk_id;
-       uint32_t graph_signature;
-       unsigned char graph_version, hash_version;
 
        if (fd < 0)
                return NULL;
@@ -108,27 +102,55 @@ struct commit_graph *load_commit_graph_one(const char *graph_file)
                die(_("graph file %s is too small"), graph_file);
        }
        graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
+       ret = parse_commit_graph(graph_map, fd, graph_size);
+
+       if (!ret) {
+               munmap(graph_map, graph_size);
+               close(fd);
+               exit(1);
+       }
+
+       return ret;
+}
+
+struct commit_graph *parse_commit_graph(void *graph_map, int fd,
+                                       size_t graph_size)
+{
+       const unsigned char *data, *chunk_lookup;
+       uint32_t i;
+       struct commit_graph *graph;
+       uint64_t last_chunk_offset;
+       uint32_t last_chunk_id;
+       uint32_t graph_signature;
+       unsigned char graph_version, hash_version;
+
+       if (!graph_map)
+               return NULL;
+
+       if (graph_size < GRAPH_MIN_SIZE)
+               return NULL;
+
        data = (const unsigned char *)graph_map;
 
        graph_signature = get_be32(data);
        if (graph_signature != GRAPH_SIGNATURE) {
                error(_("graph signature %X does not match signature %X"),
                      graph_signature, GRAPH_SIGNATURE);
-               goto cleanup_fail;
+               return NULL;
        }
 
        graph_version = *(unsigned char*)(data + 4);
        if (graph_version != GRAPH_VERSION) {
                error(_("graph version %X does not match version %X"),
                      graph_version, GRAPH_VERSION);
-               goto cleanup_fail;
+               return NULL;
        }
 
        hash_version = *(unsigned char*)(data + 5);
        if (hash_version != GRAPH_OID_VERSION) {
                error(_("hash version %X does not match version %X"),
                      hash_version, GRAPH_OID_VERSION);
-               goto cleanup_fail;
+               return NULL;
        }
 
        graph = alloc_commit_graph();
@@ -143,16 +165,27 @@ struct commit_graph *load_commit_graph_one(const char *graph_file)
        last_chunk_offset = 8;
        chunk_lookup = data + 8;
        for (i = 0; i < graph->num_chunks; i++) {
-               uint32_t chunk_id = get_be32(chunk_lookup + 0);
-               uint64_t chunk_offset = get_be64(chunk_lookup + 4);
+               uint32_t chunk_id;
+               uint64_t chunk_offset;
                int chunk_repeated = 0;
 
+               if (data + graph_size - chunk_lookup <
+                   GRAPH_CHUNKLOOKUP_WIDTH) {
+                       error(_("chunk lookup table entry missing; graph file may be incomplete"));
+                       free(graph);
+                       return NULL;
+               }
+
+               chunk_id = get_be32(chunk_lookup + 0);
+               chunk_offset = get_be64(chunk_lookup + 4);
+
                chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
 
                if (chunk_offset > graph_size - GIT_MAX_RAWSZ) {
                        error(_("improper chunk offset %08x%08x"), (uint32_t)(chunk_offset >> 32),
                              (uint32_t)chunk_offset);
-                       goto cleanup_fail;
+                       free(graph);
+                       return NULL;
                }
 
                switch (chunk_id) {
@@ -187,7 +220,8 @@ struct commit_graph *load_commit_graph_one(const char *graph_file)
 
                if (chunk_repeated) {
                        error(_("chunk id %08x appears multiple times"), chunk_id);
-                       goto cleanup_fail;
+                       free(graph);
+                       return NULL;
                }
 
                if (last_chunk_id == GRAPH_CHUNKID_OIDLOOKUP)
@@ -201,11 +235,6 @@ struct commit_graph *load_commit_graph_one(const char *graph_file)
        }
 
        return graph;
-
-cleanup_fail:
-       munmap(graph_map, graph_size);
-       close(fd);
-       exit(1);
 }
 
 static void prepare_commit_graph_one(struct repository *r, const char *obj_dir)
@@ -230,8 +259,7 @@ static void prepare_commit_graph_one(struct repository *r, const char *obj_dir)
  */
 static int prepare_commit_graph(struct repository *r)
 {
-       struct alternate_object_database *alt;
-       char *obj_dir;
+       struct object_directory *odb;
        int config_value;
 
        if (r->objects->commit_graph_attempted)
@@ -252,13 +280,11 @@ static int prepare_commit_graph(struct repository *r)
        if (!commit_graph_compatible(r))
                return 0;
 
-       obj_dir = r->objects->objectdir;
-       prepare_commit_graph_one(r, obj_dir);
        prepare_alt_odb(r);
-       for (alt = r->objects->alt_odb_list;
-            !r->objects->commit_graph && alt;
-            alt = alt->next)
-               prepare_commit_graph_one(r, alt->path);
+       for (odb = r->objects->odb;
+            !r->objects->commit_graph && odb;
+            odb = odb->next)
+               prepare_commit_graph_one(r, odb->path);
        return !!r->objects->commit_graph;
 }
 
@@ -641,26 +667,29 @@ static void add_missing_parents(struct packed_oid_list *oids, struct commit *com
 
 static void close_reachable(struct packed_oid_list *oids, int report_progress)
 {
-       int i;
+       int i, j;
        struct commit *commit;
        struct progress *progress = NULL;
-       int j = 0;
 
        if (report_progress)
                progress = start_delayed_progress(
-                       _("Annotating commits in commit graph"), 0);
+                       _("Loading known commits in commit graph"), j = 0);
        for (i = 0; i < oids->nr; i++) {
                display_progress(progress, ++j);
                commit = lookup_commit(the_repository, &oids->list[i]);
                if (commit)
                        commit->object.flags |= UNINTERESTING;
        }
+       stop_progress(&progress);
 
        /*
         * As this loop runs, oids->nr may grow, but not more
         * than the number of missing commits in the reachable
         * closure.
         */
+       if (report_progress)
+               progress = start_delayed_progress(
+                       _("Expanding reachable commits in commit graph"), j = 0);
        for (i = 0; i < oids->nr; i++) {
                display_progress(progress, ++j);
                commit = lookup_commit(the_repository, &oids->list[i]);
@@ -668,7 +697,11 @@ static void close_reachable(struct packed_oid_list *oids, int report_progress)
                if (commit && !parse_commit(commit))
                        add_missing_parents(oids, commit);
        }
+       stop_progress(&progress);
 
+       if (report_progress)
+               progress = start_delayed_progress(
+                       _("Clearing commit marks in commit graph"), j = 0);
        for (i = 0; i < oids->nr; i++) {
                display_progress(progress, ++j);
                commit = lookup_commit(the_repository, &oids->list[i]);