Handle cases when user cert database has NULL slots

chromeos/network/onc/onc_certificate_importer_impl.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chromeos/network/onc/onc_certificate_importer_impl.h"
 
 #include <cert.h>
 #include <keyhi.h>
 #include <pk11pub.h>
 
 #include "base/base64.h"
 #include "base/logging.h"
 #include "base/values.h"
 #include "chromeos/network/network_event_log.h"
 #include "chromeos/network/onc/onc_utils.h"
 #include "components/onc/onc_constants.h"
+#include "crypto/scoped_nss_types.h"
 #include "net/base/crypto_module.h"
 #include "net/base/net_errors.h"
 #include "net/cert/nss_cert_database.h"
 #include "net/cert/x509_certificate.h"
 
 #define ONC_LOG_WARNING(message)                                \
   NET_LOG_DEBUG("ONC Certificate Import Warning", message)
 #define ONC_LOG_ERROR(message)                                  \
   NET_LOG_ERROR("ONC Certificate Import Error", message)
 
@@ skipping 284 matching lines @@
   }
 
   std::string decoded_pkcs12;
   if (!base::Base64Decode(pkcs12_data, &decoded_pkcs12)) {
     ONC_LOG_ERROR(
         "Unable to base64 decode PKCS#12 data: \"" + pkcs12_data + "\".");
     return false;
   }
 
   // Since this has a private key, always use the private module.
-  scoped_refptr<net::CryptoModule> module(net::CryptoModule::CreateFromHandle(
-      target_nssdb_->GetPrivateSlot().get()));
+  crypto::ScopedPK11Slot private_slot(target_nssdb_->GetPrivateSlot());
+  if (!private_slot)
+    return false;
+  scoped_refptr<net::CryptoModule> module(
+      net::CryptoModule::CreateFromHandle(private_slot.get()));
   net::CertificateList imported_certs;
 
   int import_result = target_nssdb_->ImportFromPKCS12(
       module.get(), decoded_pkcs12, base::string16(), false, &imported_certs);
   if (import_result != net::OK) {
     ONC_LOG_ERROR(
         base::StringPrintf("Unable to import client certificate (error %s)",
                            net::ErrorToString(import_result)));
     return false;
   }
@@ skipping 20 matching lines @@
     PK11_SetPrivateKeyNickname(private_key, const_cast<char*>(guid.c_str()));
     SECKEY_DestroyPrivateKey(private_key);
   } else {
     ONC_LOG_WARNING("Unable to find private key for certificate.");
   }
   return true;
 }
 
 }  // namespace onc
 }  // namespace chromeos