From: Frédéric Lécaille <flecaille@haproxy.com>
Date: Thu, 7 Mar 2019 14:02:52 +0000 (+0100)
Subject: BUG/MAJOR: config: Wrong maxconn adjustment.
X-Git-Tag: v2.0-dev2~107
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2365fb0c9748b70ceada1094f59180e9e72b6b6b;p=thirdparty%2Fhaproxy.git

BUG/MAJOR: config: Wrong maxconn adjustment.

Before c8d5b95 the "maxconn" of the backend of dynamic "use_backend"
rules was not modified (this does not make sense and this is correct).
When implementing proxy_adjust_all_maxconn(), c8d5b95 commit missed this case.
With this patch we adjust the "maxconn" of the backend of such rules only if
they are not dynamic.

Without this patch reg-tests/http-rules/h00003.vtc could make haproxy crash.
---

diff --git a/src/proxy.c b/src/proxy.c
index e60b34a218..be810598ab 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -1521,9 +1521,14 @@ void proxy_adjust_all_maxconn()
 			 * the same backend or to the default backend.
 			 */
 			if (swrule1->be.backend != curproxy->defbe.be) {
+				/* note: swrule1->be.backend isn't a backend if the rule
+				 * is dynamic, it's an expression instead, so it must not
+				 * be dereferenced as a backend before being certain it is.
+				 */
 				list_for_each_entry(swrule2, &curproxy->switching_rules, list) {
 					if (swrule2 == swrule1) {
-						swrule1->be.backend->tot_fe_maxconn += curproxy->maxconn;
+						if (!swrule1->dynamic)
+							swrule1->be.backend->tot_fe_maxconn += curproxy->maxconn;
 						break;
 					}
 					else if (!swrule2->dynamic && swrule2->be.backend == swrule1->be.backend) {