clean up the imsg structure for getnameinfo lookup results.

fix a crash with ill-configured reverse address.

found by jturner@

ok jturner@ gilles@

diff --git a/usr.sbin/smtpd/resolver.c b/usr.sbin/smtpd/resolver.c
index fbb6ee0..c906cea 100644 (file)
--- a/usr.sbin/smtpd/resolver.c
+++ b/usr.sbin/smtpd/resolver.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: resolver.c,v 1.1 2018/07/25 16:00:48 eric Exp $       */
+/*     $OpenBSD: resolver.c,v 1.2 2018/08/29 17:56:17 eric Exp $       */
 
 /*
  * Copyright (c) 2017-2018 Eric Faurot <eric@openbsd.org>
@@ -207,8 +207,6 @@ resolver_dispatch_request(struct mproc *proc, struct imsg *imsg)
                m_create(proc, IMSG_GETNAMEINFO, reqid, 0, -1);
                m_add_int(proc, EAI_SYSTEM);
                m_add_int(proc, save_errno);
-               m_add_string(proc, "");
-               m_add_string(proc, "");
                m_close(proc);
                break;
 
@@ -286,13 +284,15 @@ resolver_dispatch_result(struct mproc *proc, struct imsg *imsg)
        case IMSG_GETNAMEINFO:
                m_get_int(&m, &gai_errno);
                m_get_int(&m, &errno);
-               m_get_string(&m, &host);
-               m_get_string(&m, &serv);
+               if (gai_errno == 0) {
+                       m_get_string(&m, &host);
+                       m_get_string(&m, &serv);
+               }
                m_end(&m);
 
                SPLAY_REMOVE(reqtree, &reqs, req);
-               req->cb_ni(req->arg, gai_errno, host[0] ? host : NULL,
-                   serv[0] ? serv : NULL);
+               req->cb_ni(req->arg, gai_errno, gai_errno ? NULL : host,
+                   gai_errno ? NULL : serv);
                free(req);
                break;
        }
@@ -344,8 +344,10 @@ resolver_getnameinfo_cb(struct asr_result *ar, void *arg)
        m_create(s->proc, IMSG_GETNAMEINFO, s->reqid, 0, -1);
        m_add_int(s->proc, ar->ar_gai_errno);
        m_add_int(s->proc, ar->ar_errno);
-       m_add_string(s->proc, s->host ? s->host : "");
-       m_add_string(s->proc, s->serv ? s->serv : "");
+       if (ar->ar_gai_errno == 0) {
+               m_add_string(s->proc, s->host);
+               m_add_string(s->proc, s->serv);
+       }
        m_close(s->proc);
 
        free(s->host);