Avoiding null pointer dereference (jonas#1096)

[tk: fixed C90 compliance and tweaked error messages]

src/graph-v1.c

@@ -474,7 +474,8 @@ graph_symbol_to_ascii(const struct graph_symbol *symbol)
 }
 
 static void
-graph_foreach_symbol(const struct graph *graph, const struct graph_canvas *canvas, graph_symbol_iterator_fn fn, void *data)
+graph_foreach_symbol(const struct graph *graph, const struct graph_canvas *canvas,
+		     graph_symbol_iterator_fn fn, void *data)
 {
 	int i;
 
@@ -491,19 +492,23 @@ struct graph *
 init_graph_v1(void)
 {
 	struct graph_v1 *graph = calloc(1, sizeof(*graph));
-	struct graph *api = &graph->api;
-
-	api->private = graph;
-	api->done = done_graph;
-	api->done_rendering = done_graph_rendering;
-	api->add_commit = graph_add_commit;
-	api->add_parent = graph_add_parent;
-	api->render_parents = graph_render_parents;
-	api->is_merge = graph_is_merge;
-	api->foreach_symbol = graph_foreach_symbol;
-	api->symbol_to_ascii = graph_symbol_to_ascii;
-	api->symbol_to_utf8 = graph_symbol_to_utf8;
-	api->symbol_to_chtype = graph_symbol_to_chtype;
+	struct graph *api = NULL;
+
+	if (graph) {
+		api = &graph->api;
+
+		api->private = graph;
+		api->done = done_graph;
+		api->done_rendering = done_graph_rendering;
+		api->add_commit = graph_add_commit;
+		api->add_parent = graph_add_parent;
+		api->render_parents = graph_render_parents;
+		api->is_merge = graph_is_merge;
+		api->foreach_symbol = graph_foreach_symbol;
+		api->symbol_to_ascii = graph_symbol_to_ascii;
+		api->symbol_to_utf8 = graph_symbol_to_utf8;
+		api->symbol_to_chtype = graph_symbol_to_chtype;
+	}
 
 	return api;
 }

src/graph-v2.c

@@ -111,16 +111,17 @@ static const char *intern_string(const char *str)
 }
 
 struct id_color {
-	char *id;
 	size_t color;
+	char id[1];
 };
 
 static struct id_color *
 id_color_new(const char *id, size_t color)
 {
-	struct id_color *node = malloc(sizeof(struct id_color));
+	struct id_color *node = malloc(sizeof(struct id_color) + strlen(id));
 
-	node->id = (char *) malloc(strlen(id) + 1);
+	if (!node)
+		die("Failed to allocate color");
 	strcpy(node->id, id);
 	node->color = color;
 
@@ -130,7 +131,6 @@ id_color_new(const char *id, size_t color)
 static void
 id_color_delete(struct id_color *node)
 {
-	free(node->id);
 	free(node);
 }
 
@@ -1228,23 +1228,23 @@ struct graph *
 init_graph_v2(void)
 {
 	struct graph_v2 *graph = calloc(1, sizeof(*graph));
-	struct graph *api;
-
-	if (!graph)
-		return NULL;
-
-	api = &graph->api;
-	api->private = graph;
-	api->done = done_graph;
-	api->done_rendering = done_graph_rendering;
-	api->add_commit = graph_add_commit;
-	api->add_parent = graph_add_parent;
-	api->is_merge = graph_is_merge;
-	api->render_parents = graph_render_parents;
-	api->foreach_symbol = graph_foreach_symbol;
-	api->symbol_to_ascii = graph_symbol_to_ascii;
-	api->symbol_to_utf8 = graph_symbol_to_utf8;
-	api->symbol_to_chtype = graph_symbol_to_chtype;
+	struct graph *api = NULL;
+
+	if (graph) {
+		api = &graph->api;
+
+		api->private = graph;
+		api->done = done_graph;
+		api->done_rendering = done_graph_rendering;
+		api->add_commit = graph_add_commit;
+		api->add_parent = graph_add_parent;
+		api->render_parents = graph_render_parents;
+		api->is_merge = graph_is_merge;
+		api->foreach_symbol = graph_foreach_symbol;
+		api->symbol_to_ascii = graph_symbol_to_ascii;
+		api->symbol_to_utf8 = graph_symbol_to_utf8;
+		api->symbol_to_chtype = graph_symbol_to_chtype;
+	}
 
 	return api;
 }

src/io.c

@@ -49,6 +49,8 @@ encoding_open(const char *fromcode)
 	}
 
 	encoding = calloc(1, sizeof(*encoding) + len);
+	if (!encoding)
+		die("Failed to allocate encoding");
 	strcpy(encoding->fromcode, fromcode);
 	encoding->cd = iconv_open(ENCODING_UTF8, fromcode);
 	if (encoding->cd == ICONV_NONE) {

src/line.c

@@ -194,7 +194,7 @@ init_line_info_color_pair(struct line_info *info, enum line_type type,
 	}
 
 	if (!realloc_color_pair(&color_pair, color_pairs, 1))
-		die("Failed to alloc color pair");
+		die("Failed to allocate color pair");
 
 	color_pair[color_pairs] = info;
 	info->color_pair = color_pairs++;

src/util.c

@@ -447,7 +447,7 @@ chunk_allocator(void *mem, size_t type_size, size_t chunk_size, size_t size, siz
 		char *tmp = realloc(mem, newsize);
 
 		if (!tmp)
-			return NULL;
+			die("Unable to reallocate chunk");
 
 		if (num_chunks_new > num_chunks) {
 			size_t oldsize = num_chunks * chunk_size * type_size;

test/tools/test-graph.c

@@ -64,7 +64,7 @@ main(int argc, const char *argv[])
 	}
 
 	if (!(graph = init_graph(GRAPH_DISPLAY_V2)))
-		die("Failed to allocated graph");
+		die("Failed to allocate graph");
 
 	if (argc > 1 && !strcmp(argv[1], "--ascii"))
 		graph_fn = graph->symbol_to_ascii;