Certificate Transparency: Require SCTs for EV certificates.

net/socket/ssl_client_socket_nss.cc

 // Copyright (c) 2012 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.
 
 // This file includes code SSLClientSocketNSS::DoVerifyCertComplete() derived
 // from AuthCertificateCallback() in
 // mozilla/security/manager/ssl/src/nsNSSCallbacks.cpp.
 
 /* ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
@@ skipping 74 matching lines @@
 #include "crypto/nss_util_internal.h"
 #include "crypto/rsa_private_key.h"
 #include "crypto/scoped_nss_types.h"
 #include "net/base/address_list.h"
 #include "net/base/connection_type_histograms.h"
 #include "net/base/dns_util.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
 #include "net/base/net_log.h"
 #include "net/cert/asn1_util.h"
+#include "net/cert/cert_policy_enforcer.h"
 #include "net/cert/cert_status_flags.h"
 #include "net/cert/cert_verifier.h"
 #include "net/cert/ct_ev_whitelist.h"
 #include "net/cert/ct_verifier.h"
 #include "net/cert/ct_verify_result.h"
 #include "net/cert/scoped_nss_types.h"
 #include "net/cert/sct_status_flags.h"
 #include "net/cert/single_request_cert_verifier.h"
 #include "net/cert/x509_certificate_net_log_param.h"
 #include "net/cert/x509_util.h"
@@ skipping 2714 matching lines @@
       ssl_config_(ssl_config),
       cert_verifier_(context.cert_verifier),
       cert_transparency_verifier_(context.cert_transparency_verifier),
       channel_id_service_(context.channel_id_service),
       ssl_session_cache_shard_(context.ssl_session_cache_shard),
       completed_handshake_(false),
       next_handshake_state_(STATE_NONE),
       nss_fd_(NULL),
       net_log_(transport_->socket()->NetLog()),
       transport_security_state_(context.transport_security_state),
+      policy_enforcer_(context.cert_policy_enforcer),
       valid_thread_id_(base::kInvalidThreadId) {
   EnterFunction("");
   InitCore();
   LeaveFunction("");
 }
 
 SSLClientSocketNSS::~SSLClientSocketNSS() {
   EnterFunction("");
   Disconnect();
   LeaveFunction("");
@@ skipping 661 matching lines @@
       (result == OK ||
        (IsCertificateError(result) && IsCertStatusMinorError(cert_status))) &&
       !transport_security_state_->CheckPublicKeyPins(
           host_and_port_.host(),
           server_cert_verify_result_.is_issued_by_known_root,
           server_cert_verify_result_.public_key_hashes,
           &pinning_failure_log_)) {
     result = ERR_SSL_PINNED_KEY_NOT_IN_CERT_CHAIN;
   }
 
-  scoped_refptr<ct::EVCertsWhitelist> ev_whitelist =
-      SSLConfigService::GetEVCertsWhitelist();
-  if (server_cert_verify_result_.cert_status & CERT_STATUS_IS_EV) {
-    if (ev_whitelist.get() && ev_whitelist->IsValid()) {
-      const SHA256HashValue fingerprint(
-          X509Certificate::CalculateFingerprint256(
-              server_cert_verify_result_.verified_cert->os_cert_handle()));
-
-      UMA_HISTOGRAM_BOOLEAN(
-          "Net.SSL_EVCertificateInWhitelist",
-          ev_whitelist->ContainsCertificateHash(
-              std::string(reinterpret_cast<const char*>(fingerprint.data), 8)));
-    }
-  }
-
   if (result == OK) {
     // Only check Certificate Transparency if there were no other errors with
     // the connection.
     VerifyCT();
 
     // Only cache the session if the certificate verified successfully.
     core_->CacheSessionIfNecessary();
   }
 
   completed_handshake_ = true;
@@ skipping 17 matching lines @@
       &ct_verify_result_,
       net_log_);
   // TODO(ekasper): wipe stapled_ocsp_response and sct_list_from_tls_extension
   // from the state after verification is complete, to conserve memory.
 
   VLOG(1) << "CT Verification complete: result " << result
           << " Invalid scts: " << ct_verify_result_.invalid_scts.size()
           << " Verified scts: " << ct_verify_result_.verified_scts.size()
           << " scts from unknown logs: "
           << ct_verify_result_.unknown_logs_scts.size();
+
+  if ((server_cert_verify_result_.cert_status & CERT_STATUS_IS_EV) &&
+      (policy_enforcer_)) {

[Ryan Sleevi, 2014/11/06 00:16:43]

Let's make sure we 'fail closed', which also addresses Matt's concern re:
contexts

if (!policy_enforcer) {
  server_cert_verify_result_.cert_status &= ~CERT_STATUS_IS_EV;
} else {
  ....
}

This guarantees we'll never grant EV for anything that doesn't go through the CT
check, and everything that does can just have it disabled if necessary (Finch or
bool, tomato tomato)

[Eran Messeri, 2014/11/20 11:49:56]

Done.

+    scoped_refptr<ct::EVCertsWhitelist> ev_whitelist =
+        SSLConfigService::GetEVCertsWhitelist();
+
+    if (!policy_enforcer_->DoesConformToCTEVPolicy(
+            server_cert_verify_result_.verified_cert.get(), ev_whitelist.get(),
+            ct_verify_result_)) {
+      VLOG(1) << "EV certificate without enough SCTs, removing EV status.";
+      server_cert_verify_result_.cert_status &= ~CERT_STATUS_IS_EV;
+    }
+  }
 }
 
 void SSLClientSocketNSS::LogConnectionTypeMetrics() const {
   UpdateConnectionTypeHistograms(CONNECTION_SSL);
   int ssl_version = SSLConnectionStatusToVersion(
       core_->state().ssl_connection_status);
   switch (ssl_version) {
     case SSL_CONNECTION_VERSION_SSL2:
       UpdateConnectionTypeHistograms(CONNECTION_SSL_SSL2);
       break;
@@ skipping 50 matching lines @@
 scoped_refptr<X509Certificate>
 SSLClientSocketNSS::GetUnverifiedServerCertificateChain() const {
   return core_->state().server_cert.get();
 }
 
 ChannelIDService* SSLClientSocketNSS::GetChannelIDService() const {
   return channel_id_service_;
 }
 
 }  // namespace net