Update CastSocket connection flow to check for receiver credentials.

chrome/browser/extensions/api/cast_channel/cast_auth_util.cc

Index: chrome/browser/extensions/api/cast_channel/cast_auth_util.cc
===================================================================
--- chrome/browser/extensions/api/cast_channel/cast_auth_util.cc	(revision 0)
+++ chrome/browser/extensions/api/cast_channel/cast_auth_util.cc	(revision 0)
@@ -0,0 +1,223 @@
+// 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 "chrome/browser/extensions/api/cast_channel/cast_auth_util.h"
+
+#include <cert.h>
+#include <cryptohi.h>
+#include <pk11pub.h>
+#include <seccomon.h>
+#include <string.h>

[Ryan Sleevi, 2013/10/23 19:14:05]

Why string.h? What function is being used from here that I missed?

[Munjal (Google), 2013/10/23 20:08:56]

Done. Meant #include <string>

+
+#include "chrome/browser/extensions/api/cast_channel/cast_channel.pb.h"
+#include "chrome/browser/extensions/api/cast_channel/cast_message_util.h"
+#include "crypto/nss_util.h"
+#include "crypto/scoped_nss_types.h"
+#include "net/cert/x509_certificate.h"
+
+namespace {
+
+// Public key of the certificate with which the peer cert should be signed.
+static const unsigned char kCAPublicKeyDER[] = {
+  0x30, 0x82, 0x03, 0x87, 0x30, 0x82, 0x02, 0x6f, 0xa0, 0x03, 0x02, 0x01,
+  0x02, 0x02, 0x01, 0x01, 0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86,
+  0xf7, 0x0d, 0x01, 0x01, 0x05, 0x05, 0x00, 0x30, 0x7c, 0x31, 0x0b, 0x30,
+  0x09, 0x06, 0x03, 0x55, 0x04, 0x06, 0x13, 0x02, 0x55, 0x53, 0x31, 0x13,
+  0x30, 0x11, 0x06, 0x03, 0x55, 0x04, 0x08, 0x0c, 0x0a, 0x43, 0x61, 0x6c,
+  0x69, 0x66, 0x6f, 0x72, 0x6e, 0x69, 0x61, 0x31, 0x16, 0x30, 0x14, 0x06,
+  0x03, 0x55, 0x04, 0x07, 0x0c, 0x0d, 0x4d, 0x6f, 0x75, 0x6e, 0x74, 0x61,
+  0x69, 0x6e, 0x20, 0x56, 0x69, 0x65, 0x77, 0x31, 0x13, 0x30, 0x11, 0x06,
+  0x03, 0x55, 0x04, 0x0a, 0x0c, 0x0a, 0x47, 0x6f, 0x6f, 0x67, 0x6c, 0x65,
+  0x20, 0x49, 0x6e, 0x63, 0x31, 0x12, 0x30, 0x10, 0x06, 0x03, 0x55, 0x04,
+  0x0b, 0x0c, 0x09, 0x47, 0x6f, 0x6f, 0x67, 0x6c, 0x65, 0x20, 0x54, 0x56,
+  0x31, 0x17, 0x30, 0x15, 0x06, 0x03, 0x55, 0x04, 0x03, 0x0c, 0x0e, 0x45,
+  0x75, 0x72, 0x65, 0x6b, 0x61, 0x20, 0x52, 0x6f, 0x6f, 0x74, 0x20, 0x43,
+  0x41, 0x30, 0x1e, 0x17, 0x0d, 0x31, 0x32, 0x31, 0x32, 0x31, 0x39, 0x30,
+  0x30, 0x34, 0x37, 0x31, 0x32, 0x5a, 0x17, 0x0d, 0x33, 0x32, 0x31, 0x32,
+  0x31, 0x34, 0x30, 0x30, 0x34, 0x37, 0x31, 0x32, 0x5a, 0x30, 0x7d, 0x31,
+  0x0b, 0x30, 0x09, 0x06, 0x03, 0x55, 0x04, 0x06, 0x13, 0x02, 0x55, 0x53,
+  0x31, 0x13, 0x30, 0x11, 0x06, 0x03, 0x55, 0x04, 0x08, 0x0c, 0x0a, 0x43,
+  0x61, 0x6c, 0x69, 0x66, 0x6f, 0x72, 0x6e, 0x69, 0x61, 0x31, 0x16, 0x30,
+  0x14, 0x06, 0x03, 0x55, 0x04, 0x07, 0x0c, 0x0d, 0x4d, 0x6f, 0x75, 0x6e,
+  0x74, 0x61, 0x69, 0x6e, 0x20, 0x56, 0x69, 0x65, 0x77, 0x31, 0x13, 0x30,
+  0x11, 0x06, 0x03, 0x55, 0x04, 0x0a, 0x0c, 0x0a, 0x47, 0x6f, 0x6f, 0x67,
+  0x6c, 0x65, 0x20, 0x49, 0x6e, 0x63, 0x31, 0x12, 0x30, 0x10, 0x06, 0x03,
+  0x55, 0x04, 0x0b, 0x0c, 0x09, 0x47, 0x6f, 0x6f, 0x67, 0x6c, 0x65, 0x20,
+  0x54, 0x56, 0x31, 0x18, 0x30, 0x16, 0x06, 0x03, 0x55, 0x04, 0x03, 0x0c,
+  0x0f, 0x45, 0x75, 0x72, 0x65, 0x6b, 0x61, 0x20, 0x47, 0x65, 0x6e, 0x31,
+  0x20, 0x49, 0x43, 0x41, 0x30, 0x82, 0x01, 0x22, 0x30, 0x0d, 0x06, 0x09,
+  0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x01, 0x05, 0x00, 0x03,
+  0x82, 0x01, 0x0f, 0x00, 0x30, 0x82, 0x01, 0x0a, 0x02, 0x82, 0x01, 0x01,
+  0x00, 0xbc, 0x22, 0x80, 0xbd, 0x80, 0xf6, 0x3a, 0x21, 0x00, 0x3b, 0xae,
+  0x76, 0x5e, 0x35, 0x7f, 0x3d, 0xc3, 0x64, 0x5c, 0x55, 0x94, 0x86, 0x34,
+  0x2f, 0x05, 0x87, 0x28, 0xcd, 0xf7, 0x69, 0x8c, 0x17, 0xb3, 0x50, 0xa7,
+  0xb8, 0x82, 0xfa, 0xdf, 0xc7, 0x43, 0x2d, 0xd6, 0x7e, 0xab, 0xa0, 0x6f,
+  0xb7, 0x13, 0x72, 0x80, 0xa4, 0x47, 0x15, 0xc1, 0x20, 0x99, 0x50, 0xcd,
+  0xec, 0x14, 0x62, 0x09, 0x5b, 0xa4, 0x98, 0xcd, 0xd2, 0x41, 0xb6, 0x36,
+  0x4e, 0xff, 0xe8, 0x2e, 0x32, 0x30, 0x4a, 0x81, 0xa8, 0x42, 0xa3, 0x6c,
+  0x9b, 0x33, 0x6e, 0xca, 0xb2, 0xf5, 0x53, 0x66, 0xe0, 0x27, 0x53, 0x86,
+  0x1a, 0x85, 0x1e, 0xa7, 0x39, 0x3f, 0x4a, 0x77, 0x8e, 0xfb, 0x54, 0x66,
+  0x66, 0xfb, 0x58, 0x54, 0xc0, 0x5e, 0x39, 0xc7, 0xf5, 0x50, 0x06, 0x0b,
+  0xe0, 0x8a, 0xd4, 0xce, 0xe1, 0x6a, 0x55, 0x1f, 0x8b, 0x17, 0x00, 0xe6,
+  0x69, 0xa3, 0x27, 0xe6, 0x08, 0x25, 0x69, 0x3c, 0x12, 0x9d, 0x8d, 0x05,
+  0x2c, 0xd6, 0x2e, 0xa2, 0x31, 0xde, 0xb4, 0x52, 0x50, 0xd6, 0x20, 0x49,
+  0xde, 0x71, 0xa0, 0xf9, 0xad, 0x20, 0x40, 0x12, 0xf1, 0xdd, 0x25, 0xeb,
+  0xd5, 0xe6, 0xb8, 0x36, 0xf4, 0xd6, 0x8f, 0x7f, 0xca, 0x43, 0xdc, 0xd7,
+  0x10, 0x5b, 0xe6, 0x3f, 0x51, 0x8a, 0x85, 0xb3, 0xf3, 0xff, 0xf6, 0x03,
+  0x2d, 0xcb, 0x23, 0x4f, 0x9c, 0xad, 0x18, 0xe7, 0x93, 0x05, 0x8c, 0xac,
+  0x52, 0x9a, 0xf7, 0x4c, 0xe9, 0x99, 0x7a, 0xbe, 0x6e, 0x7e, 0x4d, 0x0a,
+  0xe3, 0xc6, 0x1c, 0xa9, 0x93, 0xfa, 0x3a, 0xa5, 0x91, 0x5d, 0x1c, 0xbd,
+  0x66, 0xeb, 0xcc, 0x60, 0xdc, 0x86, 0x74, 0xca, 0xcf, 0xf8, 0x92, 0x1c,
+  0x98, 0x7d, 0x57, 0xfa, 0x61, 0x47, 0x9e, 0xab, 0x80, 0xb7, 0xe4, 0x48,
+  0x80, 0x2a, 0x92, 0xc5, 0x1b, 0x02, 0x03, 0x01, 0x00, 0x01, 0xa3, 0x13,
+  0x30, 0x11, 0x30, 0x0f, 0x06, 0x03, 0x55, 0x1d, 0x13, 0x04, 0x08, 0x30,
+  0x06, 0x01, 0x01, 0xff, 0x02, 0x01, 0x01, 0x30, 0x0d, 0x06, 0x09, 0x2a,
+  0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x05, 0x05, 0x00, 0x03, 0x82,
+  0x01, 0x01, 0x00, 0x8b, 0xd4, 0xa1, 0xb1, 0xcf, 0x5d, 0xcd, 0x7b, 0x6c,
+  0x48, 0x4a, 0x41, 0x1f, 0x53, 0x2f, 0x18, 0x2d, 0x32, 0x45, 0xff, 0x9e,
+  0xab, 0xd3, 0x73, 0x3e, 0x1f, 0x22, 0xd7, 0xea, 0xfa, 0x01, 0xe6, 0x73,
+  0x03, 0x0f, 0x2b, 0xc6, 0x25, 0xbb, 0xa5, 0xee, 0xc5, 0xf5, 0x45, 0xcb,
+  0x24, 0x12, 0x2a, 0xad, 0xc2, 0x5d, 0x05, 0xf4, 0x7a, 0xf5, 0xc2, 0x9b,
+  0x10, 0x16, 0x5a, 0xd1, 0x0a, 0x73, 0xc5, 0x16, 0x39, 0xa0, 0x10, 0xca,
+  0xd1, 0x68, 0x85, 0x9e, 0xfb, 0x9e, 0x26, 0x83, 0x8e, 0x58, 0xf3, 0x77,
+  0xa0, 0x4e, 0xe5, 0xdb, 0x97, 0xbe, 0x2d, 0x00, 0x5f, 0xf5, 0x94, 0xdb,
+  0xb1, 0x9d, 0x65, 0x6b, 0xfd, 0xf0, 0xd1, 0x04, 0x51, 0xdf, 0xcc, 0x92,
+  0xa6, 0x99, 0x2d, 0x71, 0xf5, 0x4d, 0xd5, 0x23, 0xfe, 0x33, 0x1c, 0xa9,
+  0xb4, 0xab, 0xc5, 0xbf, 0x1a, 0xb8, 0xd1, 0x80, 0xef, 0x89, 0xc9, 0xe2,
+  0x1f, 0x9c, 0x4c, 0x48, 0x3b, 0xa2, 0xfa, 0x02, 0x0a, 0xdc, 0x84, 0x01,
+  0x8a, 0x87, 0x02, 0xfb, 0x59, 0xee, 0xa7, 0x4c, 0x04, 0x7d, 0x74, 0x99,
+  0x87, 0x6a, 0x25, 0x44, 0xad, 0x16, 0xaa, 0xec, 0x4e, 0x35, 0x1b, 0x7c,
+  0x7b, 0x84, 0xc9, 0xb1, 0x3f, 0xe1, 0x82, 0x70, 0xe5, 0x0d, 0xe7, 0xd9,
+  0x6d, 0xfa, 0x95, 0xb6, 0xc5, 0xe4, 0x1e, 0xe8, 0x11, 0x9b, 0xd8, 0xb2,
+  0xf3, 0xa4, 0xfd, 0x13, 0xf3, 0x83, 0x4f, 0xf7, 0x07, 0x14, 0x20, 0xbb,
+  0x22, 0xa5, 0xa6, 0x8f, 0xd6, 0xb5, 0xdb, 0xa9, 0x74, 0x78, 0xe2, 0x93,
+  0x0d, 0xe5, 0x23, 0x2f, 0x05, 0x17, 0xe0, 0xb2, 0x97, 0x67, 0x34, 0x4d,
+  0x0f, 0x9c, 0x76, 0x43, 0x7b, 0xa6, 0x21, 0x4a, 0x56, 0x05, 0xf6, 0x2a,
+  0x7c, 0xf2, 0x7f, 0x12, 0x94, 0x82, 0x26, 0x29, 0x07, 0xf0, 0x0b, 0x6c,
+  0x6c, 0x79, 0x14, 0xb0, 0x74, 0xd5, 0x6c };
+
+typedef scoped_ptr_malloc<
+    CERTCertificate,
+    crypto::NSSDestroyer<CERTCertificate, CERT_DestroyCertificate> >
+ScopedCERTCertificate;
+
+// Parses out DeviceAuthMessage from CastMessage
+static bool ParseAuthMessage(
+    const extensions::api::cast_channel::CastMessage& challenge_reply,
+    extensions::api::cast_channel::DeviceAuthMessage* auth_message) {
+  if (challenge_reply.payload_type() !=
+      extensions::api::cast_channel::CastMessage_PayloadType_BINARY) {
+    DVLOG(1) << "Wrong payload type in challenge reply";
+    return false;
+  }
+  if (!challenge_reply.has_payload_binary()) {
+    DVLOG(1) << "Payload type is binary but payload_binary field not set";
+    return false;
+  }
+  if (!auth_message->ParseFromString(challenge_reply.payload_binary())) {
+    DVLOG(1) << "Cannot parse binary payload into DeviceAuthMessage";
+    return false;
+  }
+  DVLOG(1) << "Auth message: " << AuthMessageToString(*auth_message);
+  if (auth_message->has_error()) {
+    DVLOG(1) << "Auth message error: " << auth_message->error().error_type();
+    return false;
+  }
+  if (!auth_message->has_response()) {
+    DVLOG(1) << "Auth message has no response field";
+    return false;
+  }
+  return true;
+}
+
+// Authenticates the given credentials:
+// 1. |signature| verification of |data| using |certificate|.
+// 2. |certificate| is signed by a trusted CA.
+bool VerifyCredentials(const std::string& certificate,
+                       const std::string& signature,
+                       const std::string& data) {
+  crypto::EnsureNSSInit();
+  SECItem der_cert;
+  der_cert.type = siDERCertBuffer;
+  // Make a copy of certificate string so it is safe to type cast.
+  std::string certificate_copy(certificate);

[Ryan Sleevi, 2013/10/23 19:14:05]

Don't make a copy; NSS will not modify this buffer. Just cast.

[Munjal (Google), 2013/10/23 20:08:56]

Done.

[Munjal (Google), 2013/10/23 20:08:56]

Done.

+  der_cert.data = reinterpret_cast<unsigned char*>(const_cast<char*>(
+      certificate_copy.data()));
+  der_cert.len = certificate_copy.length();
+
+  // Parse into a certificate structure.
+  ScopedCERTCertificate cert(CERT_NewTempCertificate(
+      CERT_GetDefaultCertDB(), &der_cert, NULL, PR_FALSE, PR_TRUE));
+  if (!cert.get()) {
+     DVLOG(1) << "Failed to parse certificate.";
+     return false;
+  }
+
+  // Check that the certificate is signed by trusted CA.
+  SECItem trusted_ca_key_der_item;
+  trusted_ca_key_der_item.type = siDERCertBuffer;
+  trusted_ca_key_der_item.data = const_cast<unsigned char*>(kCAPublicKeyDER);
+  trusted_ca_key_der_item.len = sizeof(kCAPublicKeyDER);
+  crypto::ScopedSECKEYPublicKey ca_public_key(
+      SECKEY_ImportDERPublicKey(&trusted_ca_key_der_item, CKK_RSA));
+  SECStatus verified = CERT_VerifySignedDataWithPublicKey(
+      &cert->signatureWrap, ca_public_key.get(), NULL);
+  if (verified != SECSuccess) {
+    DVLOG(1)<< "Cert not signed by trusted CA";
+    return false;
+  }
+
+  // Verify that the |signature| matches |data|.
+  crypto::ScopedSECKEYPublicKey public_key(CERT_ExtractPublicKey(cert.get()));
+  if (!public_key.get()) {
+    DVLOG(1) << "Unable to extract public key from certificate.";
+    return false;
+  }
+  SECItem signature_item;
+  signature_item.type = siBuffer;
+  // Make a copy of signature string to it is safe to type cast.
+  std::string signature_copy(signature);

[Ryan Sleevi, 2013/10/23 19:14:05]

Don't make a copy

[Munjal (Google), 2013/10/23 20:08:56]

Done.

+  signature_item.data = reinterpret_cast<unsigned char*>(
+      const_cast<char*>(signature_copy.data()));
+  signature_item.len = signature_copy.length();
+  verified = VFY_VerifyDataDirect(
+      reinterpret_cast<unsigned char*>(const_cast<char*>(data.c_str())),

[Ryan Sleevi, 2013/10/23 19:14:05]

.data()

[Munjal (Google), 2013/10/23 20:08:56]

Done.

+      data.size(),
+      public_key.get(),
+      &signature_item,
+      SEC_OID_PKCS1_RSA_ENCRYPTION,
+      SEC_OID_SHA1, NULL, NULL);
+
+  if (verified != SECSuccess) {
+    DVLOG(1) << "Signed blobs did not match.";
+    return false;
+  }
+  return true;
+}
+
+}  // namespace
+
+namespace extensions {
+namespace api {
+namespace cast_channel {
+
+bool AuthenticateChallengeReply(const CastMessage& challenge_reply,
+                                const std::string& peer_cert) {
+  if (peer_cert.empty())
+    return false;
+
+  DVLOG(1) << "Challenge reply: " << CastMessageToString(challenge_reply);
+  DeviceAuthMessage auth_message;
+  if (!ParseAuthMessage(challenge_reply, &auth_message))
+    return false;
+
+  const AuthResponse& response = auth_message.response();
+  return VerifyCredentials(response.client_auth_certificate(),
+                           response.signature(),
+                           peer_cert);
+}
+
+}  // namespace cast_channel
+}  // namespace api
+}  // namespace extensions