dict-client: Fix potential crash if iteration fails to send the command

diff --git a/src/lib-dict/dict-client.c b/src/lib-dict/dict-client.c
index 43cf4adb2d403ff05486ccb66f738d5cd55775e4..2ecaa1ecfdb703f961811df1bdbdeddbb010a200 100644 (file)
--- a/src/lib-dict/dict-client.c
+++ b/src/lib-dict/dict-client.c
@@ -108,6 +108,7 @@ struct client_dict_iterate_context {
 
        bool cmd_sent;
        bool seen_results;
+       bool iterating;
        bool finished;
        bool deinit;
 };
@@ -1073,13 +1074,17 @@ client_dict_iter_api_callback(struct client_dict_iterate_context *ctx,
                                  cmd->query);
                }
        }
-       if (ctx->ctx.async_callback != NULL) {
+       if (ctx->ctx.async_callback == NULL) {
+               /* synchronous lookup */
+               io_loop_stop(dict->dict.ioloop);
+       } else if (ctx->iterating) {
+               /* We're already in client_dict_iterate(). Don't call the
+                  async callback, because it would just recurse and possibly
+                  break. */
+       } else {
                dict_pre_api_callback(&dict->dict);
                ctx->ctx.async_callback(ctx->ctx.async_context);
                dict_post_api_callback(&dict->dict);
-       } else {
-               /* synchronous lookup */
-               io_loop_stop(dict->dict.ioloop);
        }
 }
 
@@ -1220,7 +1225,9 @@ static bool client_dict_iterate(struct dict_iterate_context *_ctx,
        }
        if (!ctx->cmd_sent) {
                ctx->cmd_sent = TRUE;
+               ctx->iterating = TRUE;
                client_dict_iterate_cmd_send(ctx);
+               ctx->iterating = FALSE;
                return client_dict_iterate(_ctx, key_r, values_r);
        }
        ctx->ctx.has_more = !ctx->finished;