Refactoring of Cast-related crypto code

chrome/common/extensions/api/networking_private/networking_private_crypto.cc

 // Copyright 2014 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/common/extensions/api/networking_private/networking_private_crypto.h"
 
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/strings/string_util.h"
+#include "extensions/common/cast/cast_cert_validator.h"
+#include "net/cert/pem_tokenizer.h"
+
+namespace {
+
+namespace cast_crypto = ::extensions::core_api::cast_crypto;
+
+}  // namespace
+
 namespace networking_private_crypto {
 
-const uint8 kTrustedCAPublicKeyDER[] = {
-    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};
+bool VerifyCredentials(
+    const std::string& certificate,
+    const std::vector<std::string>& intermediate_certificates,
+    const std::string& signature,
+    const std::string& data,
+    const std::string& connected_mac) {
+  static const char kErrorPrefix[] = "Device verification failed. ";
 
-const size_t kTrustedCAPublicKeyDERLength = sizeof(kTrustedCAPublicKeyDER);
+  std::vector<std::string> headers;
+  headers.push_back("CERTIFICATE");
+
+  // Convert certificate from PEM to raw DER
+  net::PEMTokenizer pem_tok(certificate, headers);
+  if (!pem_tok.GetNext()) {
+    LOG(ERROR) << kErrorPrefix << "Failed to parse device certificate.";
+    return false;
+  }
+  std::string der_certificate = pem_tok.data();
+
+  // Convert intermediate certificates from PEM to raw DER
+  std::vector<std::string> der_intermediate_certificates;
+  for (size_t idx = 0; idx < intermediate_certificates.size(); ++idx) {
+    net::PEMTokenizer ica_pem_tok(intermediate_certificates[idx], headers);
+    if (ica_pem_tok.GetNext()) {
+      der_intermediate_certificates.push_back(ica_pem_tok.data());
+    } else {
+      LOG(WARNING) << "Failed to parse intermediate certificates.";
+    }
+  }
+
+  // Verify device certificate
+  scoped_ptr<cast_crypto::CertVerificationContext> verification_context;
+  cast_crypto::VerificationResult verification_result =
+      cast_crypto::VerifyDeviceCert(der_certificate,
+                                    der_intermediate_certificates,
+                                    &verification_context);
+
+  if (verification_result.Failure()) {
+    LOG(ERROR) << kErrorPrefix << verification_result.GetLogString();
+    return false;
+  }
+
+  // Check that the device listed in the certificate is correct.
+  // Something like evt_e161 001a11ffacdf
+  std::string common_name = verification_context->GetCommonName();
+  std::string translated_mac;
+  base::RemoveChars(connected_mac, ":", &translated_mac);
+  if (!EndsWith(common_name, translated_mac, false)) {
+    LOG(ERROR) << kErrorPrefix << "MAC addresses don't match.";
+    return false;
+  }
+
+  // Use the public key from verified certificate to verify |signature| over
+  // |data|.
+  verification_result =
+      verification_context->VerifySignatureOverData(signature, data);
+
+  if (verification_result.Failure()) {
+    LOG(ERROR) << kErrorPrefix << verification_result.GetLogString();
+    return false;
+  }
+  return true;
+}
 
 }  // namespace networking_private_crypto