From: Aki Tuomi <aki.tuomi@open-xchange.com>
Date: Mon, 3 Oct 2022 15:45:36 +0000 (+0300)
Subject: lib-dns: dns-lua - Return error correctly
X-Git-Tag: 2.4.0~3584
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7045e226957fef5980bbdd9a749ec3f143f241ab;p=thirdparty%2Fdovecot%2Fcore.git

lib-dns: dns-lua - Return error correctly

Code was checking wrong place in stack, and thus only returned top of stack.
Check the right place for error.

Broken in a4e3ea5089400ab2037d3bdd0daa0ed351c1be46
---

diff --git a/src/lib-dns/dns-lua.c b/src/lib-dns/dns-lua.c
index 0ed7c43494..946cca9447 100644
--- a/src/lib-dns/dns-lua.c
+++ b/src/lib-dns/dns-lua.c
@@ -31,7 +31,7 @@ static int
 lua_dns_client_async_continue(lua_State *L, int status ATTR_UNUSED,
 			      lua_KContext ctx ATTR_UNUSED)
 {
-	if (lua_isnil(L, -1))
+	if (lua_isnil(L, -3))
 		return 3;
 	else
 		return 1;
@@ -56,7 +56,7 @@ lua_dns_client_lookup_callback(const struct dns_lookup_result *result,
 	}
 
 	if (lua_lookup->resume)
-		dlua_pcall_yieldable_resume(L, 1);
+		dlua_pcall_yieldable_resume(L, result->ret == 0 ? 1 : 3);
 	i_free(lua_lookup);
 }
 
diff --git a/src/lib-lua/test-dns-lua.c b/src/lib-lua/test-dns-lua.c
index fd43dd036c..3aa4b5de03 100644
--- a/src/lib-lua/test-dns-lua.c
+++ b/src/lib-lua/test-dns-lua.c
@@ -141,6 +141,10 @@ static void test_dns_lua(void)
 "  assert(#arr == 2)\n"
 "  assert(arr[1] == '127.0.0.1')\n"
 "  assert(arr[2] == '127.0.0.2')\n"
+"  local arr, error, errno = client:lookup('invalid..name')\n"
+"  assert(arr == nil)\n"
+"  assert(errno == -4)\n"
+"  assert(error == \"Unknown host\")\n"
 "end\n";
 	test_begin("dns lua lookup");