Update third_party/nss to NSS 3.15.4.

nss/lib/ckfw/builtins/bfind.c

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef BUILTINS_H
 #include "builtins.h"
 #endif /* BUILTINS_H */
 
 /*
  * builtins/find.c
@@ skipping 97 matching lines @@
   CK_ATTRIBUTE_PTR a,
   const NSSItem *b
 )
 {
   PRBool prb;
 
   if( a->ulValueLen != b->size ) {
     /* match a decoded serial number */
     if ((a->type == CKA_SERIAL_NUMBER) && (a->ulValueLen < b->size)) {
         int len;
-        unsigned char *data;
+        unsigned char *data = NULL;
 
         len = builtins_derUnwrapInt(b->data,b->size,&data);
-        if ((len == a->ulValueLen) && 
-                nsslibc_memequal(a->pValue, data, len, (PRStatus *)NULL)) {
+        if (data &&
+            (len == a->ulValueLen) && 
+            nsslibc_memequal(a->pValue, data, len, (PRStatus *)NULL)) {
             return CK_TRUE;
         }
     }
     return CK_FALSE;
   }
 
   prb = nsslibc_memequal(a->pValue, b->data, b->size, (PRStatus *)NULL);
 
   if( PR_TRUE == prb ) {
     return CK_TRUE;
@@ skipping 108 matching lines @@
  loser:
   nss_ZFreeIf(temp);
   nss_ZFreeIf(fo);
   nss_ZFreeIf(rv);
   if ((NSSArena *)NULL != arena) {
      NSSArena_Destroy(arena);
   }
   return (NSSCKMDFindObjects *)NULL;
 }