glibc-2.23: Fix CVE-2016-5417

[No upstream tracking] -- https://bugzilla.redhat.com/show_bug.cgi?id=1362534

resolv/res_init.c:Fix resource leak in resolver

The number of currently defined nameservers is stored in ->nscount,
whereas ->_u._ext.nscount is set by __libc_res_nsend only after local
initializations.

Upstream-Status: Backport
CVE: CVE-2016-5417
Signed-off-by: Andrej Valek <andrej.valek@siemens.com>
Signed-off-by: Pascal Bach <pascal.bach@siemens.com>

diff --git a/resolv/res_init.c b/resolv/res_init.c
index e0b6a80..6c951f5 100644
--- a/resolv/res_init.c
+++ b/resolv/res_init.c
@@ -594,7 +594,7 @@ __res_iclose(res_state statp, bool free_addr) {
 		statp->_vcsock = -1;
 		statp->_flags &= ~(RES_F_VC | RES_F_CONN);
 	}
-	for (ns = 0; ns < statp->_u._ext.nscount; ns++)
+	for (ns = 0; ns < statp->nscount; ns++)
 		if (statp->_u._ext.nsaddrs[ns]) {
 			if (statp->_u._ext.nssocks[ns] != -1) {
 				close_not_cancel_no_status(statp->_u._ext.nssocks[ns]);