SIGSEGV on murder frontend if backend times out on TLS connection

[MASHtm]

My frontends use TLS connections to my backends. Recently one of our backends got loaded due to twoskip locking issues reported earlier. Afterwards I found many coredumps on my frontends all complaining about a NULL Ptr parsing the capabilities. As far as I can tell this is due to the fact that in backend.c the returncode of backend_starttls() is not checked and backend_login is called unconditionally. This is at least true for 2.5.x and HEAD.

This should fix it IMO (based on 2.5.x)

--- backend.c.orig	2016-10-13 01:04:09.392344552 +0200
+++ backend.c	2017-10-17 14:58:24.862930400 +0200
@@ -1016,7 +1016,10 @@
     prot_setisclient(ret->out, 1);
 
     /* Start TLS if required */
-    if (do_tls) r = backend_starttls(ret, NULL, NULL, NULL);
+    if (do_tls) {
+        r = backend_starttls(ret, NULL, NULL, NULL);
+        if (r) goto error;
+    }
 
     /* Login to the server */
     if (prot->type == TYPE_SPEC)

[elliefm]

Patch looks good, thanks! Applying it to the current branches now...