From fe37229f7cf1b90c146aa5b970006ebe7f4291fd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Grubbstr=C3=B6m=20=28Grubba=29?=
<grubba@grubba.org>
Date: Fri, 30 Oct 2020 12:21:38 +0100
Subject: [PATCH] Protocols.DNS: Improved error handling when calling async
callbacks.
Do not complain if the originator for an asynchronous request has
gone away.
Do not output a misleading message about failing to read the UDP
packet or connection refused, if it is the user callback that fails.
Fixes #10057.
---
.gitattributes | 1 -
lib/modules/Protocols.pmod/DNS.pmod | 16 +++++++++++++---
2 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/.gitattributes b/.gitattributes
index c506618ef1..45046235ef 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -141,7 +141,6 @@ testfont binary
/lib/modules/Parser.pmod/module.pmod foreign_ident
/lib/modules/Pike.pmod foreign_ident
/lib/modules/Pike.pmod/module.pmod foreign_ident
-/lib/modules/Protocols.pmod/DNS.pmod foreign_ident
/lib/modules/Protocols.pmod/HTTP.pmod/Query.pike foreign_ident
/lib/modules/Protocols.pmod/HTTP.pmod/Session.pike foreign_ident
/lib/modules/Protocols.pmod/IMAP.pmod/imap_server.pike foreign_ident
diff --git a/lib/modules/Protocols.pmod/DNS.pmod b/lib/modules/Protocols.pmod/DNS.pmod
index d7fa2dabe6..30621c0831 100644
--- a/lib/modules/Protocols.pmod/DNS.pmod
+++ b/lib/modules/Protocols.pmod/DNS.pmod
@@ -1,4 +1,4 @@
-// $Id: DNS.pmod,v 1.81 2003/10/21 03:10:39 nilsson Exp $
+// $Id$
// Not yet finished -- Fredrik Hubinette
//! Domain Name System
@@ -1132,18 +1132,28 @@ class async_client
static private void rec_data(mapping m)
{
mixed err;
+ mapping res;
if (err = catch {
if(m->port != 53 || !has_value(nameservers, m->ip)) return;
sscanf(m->data,"%2c",int id);
object r=requests[id];
if(!r) return;
m_delete(requests,id);
- r->callback(r->domain,decode_res(m->data),@r->args);
- destruct(r);
+ res = decode_res(m->data);
}) {
werror("DNS: Failed to read UDP packet. Connection refused?\n%s\n",
describe_backtrace(err));
}
+ // NB: The callback may have gone away during our processing.
+ // Don't complain if that is the case.
+ if (r->callback && (err = catch {
+ r->callback(r->domain, res, @r->args);
+ })) {
+ werror("DNS: Callback failed:\n"
+ "%s\n",
+ describe_backtrace(err));
+ }
+ destruct(r);
}
static private void generic_get(string d,
--
GitLab