From: Witold Kręcicki <wpk@isc.org>
Date: Thu, 3 Jan 2019 12:06:39 +0000 (+0100)
Subject: When a forwarder fails and we're not in a forward-only mode we
X-Git-Tag: v9.13.6~50^2
X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=cfa2804e5a13aedd4fb36496f995cfdc7eb7a6c5;p=thirdparty%2Fbind9.git

When a forwarder fails and we're not in a forward-only mode we
go back to regular resolution. When this happens the fetch timer is
already running, and we might end up in a situation where we we create
a fetch for qname-minimized query and after that the timer is triggered
and the query is retried (fctx_try) - which causes relaunching of
qname-minimization fetch - and since we already have a qmin fetch
for this fctx - assertion failure.

This fix stops the timer when doing qname minimization - qmin fetch
internal timer should take care of all the possible timeouts.
---

diff --git a/CHANGES b/CHANGES
index c3be4bc5b18..201b7f2c248 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,7 @@
+5138.	[bug]		Under some circumstances named could hit an assertion
+			failure when doing qname minimization when using
+			forwarders. [GL #797]
+
 5137.	[func]		named now logs messages whenever a mirror zone becomes
 			usable or unusable for resolution purposes. [GL #818]
 
diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index da9083010e5..1d63e86ec00 100644
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -4040,9 +4040,11 @@ fctx_try(fetchctx_t *fctx, bool retrying, bool badcache) {
 		options &= ~DNS_FETCHOPT_QMINIMIZE;
 		fctx_increference(fctx);
 		task = res->buckets[bucketnum].task;
+		fctx_stoptimer(fctx);
 		result = dns_resolver_createfetch(fctx->res, &fctx->qminname,
 						  fctx->qmintype, &fctx->domain,
-						  &fctx->nameservers, NULL, NULL, 0,
+						  &fctx->nameservers,
+						  NULL, NULL, 0,
 						  options, 0, fctx->qc, task,
 						  resume_qmin, fctx,
 						  &fctx->qminrrset, NULL,
@@ -4371,13 +4373,12 @@ fctx_timeout(isc_task_t *task, isc_event_t *event) {
 		 * timer.
 		 */
 		result = fctx_starttimer(fctx);
-		if (result != ISC_R_SUCCESS)
+		if (result != ISC_R_SUCCESS) {
 			fctx_done(fctx, result, __LINE__);
-		else
-			/*
-			 * Keep trying.
-			 */
+		} else {
+			/* Keep trying */
 			fctx_try(fctx, true, false);
+		}
 	}
 
 	isc_event_free(&event);