From: Baptiste Assmann <bedis9@gmail.com>
Date: Wed, 28 Oct 2015 01:03:32 +0000 (+0100)
Subject: BUG/MAJOR: dns: first DNS response packet not matching queried hostname may lead... 
X-Git-Tag: v1.7-dev1~64
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fad0318c74257ce5deb7c68f68ca37cdf61cc9a9;p=thirdparty%2Fhaproxy.git

BUG/MAJOR: dns: first DNS response packet not matching queried hostname may lead to a loop

The status DNS_UPD_NAME_ERROR returned by dns_get_ip_from_response and
which means the queried name can't be found in the response was
improperly processed (fell into the default case).
This lead to a loop where HAProxy simply resend a new query as soon as
it got a response for this status and in the only case where such type
of response is the very first one received by the process.

This should be backported into 1.6 branch
---

diff --git a/src/server.c b/src/server.c
index dcc5961051..c92623d481 100644
--- a/src/server.c
+++ b/src/server.c
@@ -2620,6 +2620,17 @@ int snr_resolution_cb(struct dns_resolution *resolution, struct dns_nameserver *
 			}
 			goto stop_resolution;
 
+		case DNS_UPD_NAME_ERROR:
+			/* if this is not the last expected response, we ignore it */
+			if (resolution->nb_responses < nameserver->resolvers->count_nameservers)
+				return 0;
+			/* update resolution status to OTHER error type */
+			if (resolution->status != RSLV_STATUS_OTHER) {
+				resolution->status = RSLV_STATUS_OTHER;
+				resolution->last_status_change = now_ms;
+			}
+			goto stop_resolution;
+
 		default:
 			goto invalid;