From: Willy Tarreau <w@1wt.eu>
Date: Wed, 3 Oct 2018 08:20:19 +0000 (+0200)
Subject: BUG/MINOR: backend: check that the mux installed properly
X-Git-Tag: v1.9-dev4~89
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=33dd4ef81245bb868b22f99b9be45d0791131eec;p=thirdparty%2Fhaproxy.git

BUG/MINOR: backend: check that the mux installed properly

The return value from conn_install_mux() was not checked, so if an
inconsistency happens in the code, or a memory allocation fails while
initializing the mux, we can crash while using an uninitialized mux.
In practice the code inconsistency does not really happen since we
cannot configure such a situation, except during development, but
the out of memory condition could definitely happen.

This should be backported to 1.8 (the code is a bit different there,
there are two calls to conn_install_mux()).
---

diff --git a/src/backend.c b/src/backend.c
index e66ee4a4b0..b154b80457 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -1189,7 +1189,8 @@ int connect_server(struct stream *s)
 		else
 			return SF_ERR_INTERNAL;  /* how did we get there ? */
 
-		conn_install_mux_be(srv_conn, srv_cs);
+		if (conn_install_mux_be(srv_conn, srv_cs) < 0)
+			return SF_ERR_INTERNAL;
 
 		/* process the case where the server requires the PROXY protocol to be sent */
 		srv_conn->send_proxy_ofs = 0;