MFC r320216: 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)
Approved by:	re (kib)

1 files changed, 2 insertions, 1 deletions

diff --git a/lib/libc/rpc/rpcb_clnt.c b/lib/libc/rpc/rpcb_clnt.c
index f9d89c1..8c9b8ca 100644
--- a/lib/libc/rpc/rpcb_clnt.c
+++ b/lib/libc/rpc/rpcb_clnt.c
@@ -499,14 +499,15 @@ try_nconf:
 					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);