From 1fa9b754c45de776ad53f16cdf9b2a02c71f3965 Mon Sep 17 00:00:00 2001
From: delphij <delphij@FreeBSD.org>
Date: Thu, 22 Jun 2017 05:10:16 +0000
Subject: [PATCH] Fix use-after-free introduced in r300388.

In r300388, endnetconfig() was called on nc_handle which would release
the associated netconfig structure, which means tmpnconf->nc_netid
would be a use-after-free.

Solve this by doing endnetconfig() in return paths instead.

Reported by:	jemalloc via kevlo
Reviewed by:	cem, ngie (earlier version)
MFC after:	3 days
Differential Revision:    https://reviews.freebsd.org/D11288
---
 lib/libc/rpc/rpcb_clnt.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/libc/rpc/rpcb_clnt.c b/lib/libc/rpc/rpcb_clnt.c
index f9d89c1ae814..8c9b8ca22bfb 100644
--- a/lib/libc/rpc/rpcb_clnt.c
+++ b/lib/libc/rpc/rpcb_clnt.c
@@ -499,14 +499,15 @@ local_rpcb(void)
 					hostname = IN6_LOCALHOST_STRING;
 			}
 		}
-		endnetconfig(nc_handle);
 		if (tmpnconf == NULL) {
+			endnetconfig(nc_handle);
 			rpc_createerr.cf_stat = RPC_UNKNOWNPROTO;
 			mutex_unlock(&loopnconf_lock);
 			return (NULL);
 		}
 		loopnconf = getnetconfigent(tmpnconf->nc_netid);
 		/* loopnconf is never freed */
+		endnetconfig(nc_handle);
 	}
 	mutex_unlock(&loopnconf_lock);
 	client = getclnthandle(hostname, loopnconf, NULL);