From: Stephan Bosch <stephan.bosch@dovecot.fi>
Date: Mon, 3 Apr 2017 22:32:07 +0000 (+0200)
Subject: lib-http: client: Fixed race condition between DNS refresh lookup and a soft connecti... 
X-Git-Tag: 2.2.31.rc1~183
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=05e721c729fa857deb188d5d04f2200c7dcf4983;p=thirdparty%2Fdovecot%2Fcore.git

lib-http: client: Fixed race condition between DNS refresh lookup and a soft connection timeout.

The refreshing DNS lookup cleared all the IPs, but the soft connection timeout (and maybe other code) still relied on them.
Adding tests everywhere for host->ips_count == 0 is annoying, so I changed the DNS lookup code such that the stale IPs remain present while the DNS lookup is being performed.
The pending lookup prevents new connections through http_client_host_refresh(), so this will not create potentially useless connections.
---

diff --git a/src/lib-http/http-client-host.c b/src/lib-http/http-client-host.c
index b6f68f6981..dc3e592385 100644
--- a/src/lib-http/http-client-host.c
+++ b/src/lib-http/http-client-host.c
@@ -108,8 +108,6 @@ static void http_client_host_lookup
 	i_assert(!host->explicit_ip);
 	i_assert(host->dns_lookup == NULL);
 
-	host->ips_count = 0;
-
 	if (client->set.dns_client != NULL) {
 		http_client_host_debug(host,
 			"Performing asynchronous DNS lookup");
@@ -147,9 +145,7 @@ static void http_client_host_lookup
 		host->ips_count = ips_count;
 		host->ips = i_new(struct ip_addr, ips_count);
 		memcpy(host->ips, ips, ips_count * sizeof(*ips));
-	}
 
-	if (host->ips_count > 0) {
 		host->ips_timeout = ioloop_timeval;
 		timeval_add_msecs(&host->ips_timeout, client->set.dns_ttl_msecs);
 	}