remoting/protocol/auth_util.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "remoting/protocol/auth_util.h"
   6
   7 #include "base/base64.h"
   8 #include "base/logging.h"
   9 #include "base/strings/string_util.h"
  10 #include "crypto/hmac.h"
  11 #include "crypto/sha2.h"
  12 #include "net/base/net_errors.h"
  13 #include "net/socket/ssl_socket.h"
  14
  15 namespace remoting {
  16 namespace protocol {
  17
  18 const char kClientAuthSslExporterLabel[] =
  19     "EXPORTER-remoting-channel-auth-client";
  20 const char kHostAuthSslExporterLabel[] =
  21     "EXPORTER-remoting-channel-auth-host";
  22
  23 const char kSslFakeHostName[] = "chromoting";
  24
  25 std::string GenerateSupportAuthToken(const std::string& jid,
  26                                      const std::string& access_code) {
  27   std::string sha256 = crypto::SHA256HashString(jid + " " + access_code);
  28   std::string sha256_base64;
  29   if (!base::Base64Encode(sha256, &sha256_base64)) {
  30     LOG(FATAL) << "Failed to encode auth token";
  31   }
  32   return sha256_base64;
  33 }
  34
  35 bool VerifySupportAuthToken(const std::string& jid,
  36                             const std::string& access_code,
  37                             const std::string& auth_token) {
  38   std::string expected_token =
  39       GenerateSupportAuthToken(jid, access_code);
  40   return expected_token == auth_token;
  41 }
  42
  43 // static
  44 std::string GetAuthBytes(net::SSLSocket* socket,
  45                          const base::StringPiece& label,
  46                          const base::StringPiece& shared_secret) {
  47   // Get keying material from SSL.
  48   unsigned char key_material[kAuthDigestLength];
  49   int export_result = socket->ExportKeyingMaterial(
  50       label, false, "", key_material, kAuthDigestLength);
  51   if (export_result != net::OK) {
  52     LOG(ERROR) << "Error fetching keying material: " << export_result;
  53     return std::string();
  54   }
  55
  56   // Generate auth digest based on the keying material and shared secret.
  57   crypto::HMAC response(crypto::HMAC::SHA256);
  58   if (!response.Init(key_material, kAuthDigestLength)) {
  59     NOTREACHED() << "HMAC::Init failed";
  60     return std::string();
  61   }
  62   unsigned char out_bytes[kAuthDigestLength];
  63   if (!response.Sign(shared_secret, out_bytes, kAuthDigestLength)) {
  64     NOTREACHED() << "HMAC::Sign failed";
  65     return std::string();
  66   }
  67
  68   return std::string(out_bytes, out_bytes + kAuthDigestLength);
  69 }
  70
  71 }  // namespace protocol
  72 }  // namespace remoting