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| 1 // Copyright 2014 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/host/gnubby_util.h" |
| 6 |
| 7 #include <algorithm> |
| 8 #include <vector> |
| 9 |
| 10 #include "base/base64.h" |
| 11 #include "base/json/json_reader.h" |
| 12 #include "base/json/json_writer.h" |
| 13 #include "base/logging.h" |
| 14 #include "base/memory/scoped_ptr.h" |
| 15 #include "base/values.h" |
| 16 #include "remoting/base/logging.h" |
| 17 |
| 18 namespace remoting { |
| 19 |
| 20 namespace { |
| 21 |
| 22 // Failure code to use when the code from the webapp response isn't available. |
| 23 const int kGnubbyResponseFail = 1; |
| 24 |
| 25 const int kSsh2AgentcGnubbySignRequest = 101; // 0x65 |
| 26 const int kSsh2AgentcGnubbySignResponse = 102; // 0x66 |
| 27 |
| 28 const char kAppIdHash[] = "appIdHash"; |
| 29 const char kChallengeHash[] = "challengeHash"; |
| 30 const char kCode[] = "code"; |
| 31 const char kKeyHandle[] = "keyHandle"; |
| 32 const char kResponseData[] = "responseData"; |
| 33 const char kSignData[] = "signData"; |
| 34 const char kSignReply[] = "sign_helper_reply"; |
| 35 const char kSignRequest[] = "sign_helper_request"; |
| 36 const char kSignatureData[] = "signatureData"; |
| 37 const char kTimeout[] = "timeout"; |
| 38 const char kType[] = "type"; |
| 39 const char kVersion[] = "version"; |
| 40 |
| 41 void WebSafeBase64Encode(const std::string& data, std::string* encoded_data) { |
| 42 base::Base64Encode(data, encoded_data); |
| 43 |
| 44 std::replace(encoded_data->begin(), encoded_data->end(), '+', '-'); |
| 45 std::replace(encoded_data->begin(), encoded_data->end(), '/', '_'); |
| 46 encoded_data->erase( |
| 47 std::remove(encoded_data->begin(), encoded_data->end(), '='), |
| 48 encoded_data->end()); |
| 49 } |
| 50 |
| 51 void WebSafeBase64Decode(const std::string& encoded_data, std::string* data) { |
| 52 std::string temp(encoded_data); |
| 53 std::replace(temp.begin(), temp.end(), '-', '+'); |
| 54 std::replace(temp.begin(), temp.end(), '_', '/'); |
| 55 |
| 56 int num_equals = temp.length() % 3; |
| 57 temp.append(num_equals, '='); |
| 58 |
| 59 base::Base64Decode(temp, data); |
| 60 } |
| 61 |
| 62 bool DecodeDataFromDictionary(const base::DictionaryValue& dictionary, |
| 63 const std::string& path, |
| 64 std::string* data) { |
| 65 std::string encoded_data; |
| 66 bool result = dictionary.GetString(path, &encoded_data); |
| 67 if (result) { |
| 68 WebSafeBase64Decode(encoded_data, data); |
| 69 } else { |
| 70 LOG(ERROR) << "Failed to get dictionary value " << path; |
| 71 data->erase(); |
| 72 } |
| 73 return result; |
| 74 } |
| 75 |
| 76 // Class to read gnubby blob data. |
| 77 class BlobReader { |
| 78 public: |
| 79 // Create a blob with the given data. Does not take ownership of the memory. |
| 80 BlobReader(const uint8_t* data, size_t data_len); |
| 81 virtual ~BlobReader(); |
| 82 |
| 83 // Read a byte from the blob. Returns true on success. |
| 84 bool ReadByte(uint8_t* value); |
| 85 |
| 86 // Read a four byte size from the blob. Returns true on success. |
| 87 bool ReadSize(size_t* value); |
| 88 |
| 89 // Read a size-prefixed blob. Returns true on success. |
| 90 bool ReadBlobReader(scoped_ptr<BlobReader>* value); |
| 91 |
| 92 // Read a size-prefixed string from the blob. Returns true on success. |
| 93 bool ReadString(std::string* value); |
| 94 |
| 95 private: |
| 96 // The blob data. |
| 97 const uint8_t* data_; |
| 98 |
| 99 // The length of the blob data. |
| 100 size_t data_len_; |
| 101 |
| 102 // The current read index. |
| 103 size_t index_; |
| 104 |
| 105 DISALLOW_COPY_AND_ASSIGN(BlobReader); |
| 106 }; |
| 107 |
| 108 // Class to write gnubby blob data. |
| 109 class BlobWriter { |
| 110 public: |
| 111 BlobWriter(); |
| 112 virtual ~BlobWriter(); |
| 113 |
| 114 // Write a byte to the blob. |
| 115 void WriteByte(uint8_t value); |
| 116 |
| 117 // Write a four byte size to the blob. |
| 118 void WriteSize(size_t value); |
| 119 |
| 120 // Write a size-prefixed blob to the blob. |
| 121 void WriteBlobWriter(const BlobWriter& value); |
| 122 |
| 123 // Write a size-prefixed string to the blob. |
| 124 void WriteString(const std::string& value); |
| 125 |
| 126 // Returns the blob data. |
| 127 std::string GetData() const; |
| 128 |
| 129 private: |
| 130 // The blob data. |
| 131 std::vector<uint8_t> data_; |
| 132 |
| 133 DISALLOW_COPY_AND_ASSIGN(BlobWriter); |
| 134 }; |
| 135 |
| 136 BlobReader::BlobReader(const uint8_t* data, size_t data_len) |
| 137 : data_(data), data_len_(data_len), index_(0) {} |
| 138 |
| 139 BlobReader::~BlobReader() {} |
| 140 |
| 141 bool BlobReader::ReadByte(uint8_t* value) { |
| 142 if (data_len_ < index_) { |
| 143 *value = 0; |
| 144 return false; |
| 145 } |
| 146 *value = data_[index_++]; |
| 147 return true; |
| 148 } |
| 149 |
| 150 bool BlobReader::ReadSize(size_t* value) { |
| 151 if (data_len_ < (index_ + 4)) { |
| 152 *value = 0; |
| 153 return false; |
| 154 } |
| 155 *value = ((data_[index_] & 255) << 24) + ((data_[index_ + 1] & 255) << 16) + |
| 156 ((data_[index_ + 2] & 255) << 8) + (data_[index_ + 3] & 255); |
| 157 index_ += 4; |
| 158 return true; |
| 159 } |
| 160 |
| 161 bool BlobReader::ReadBlobReader(scoped_ptr<BlobReader>* value) { |
| 162 size_t blob_size; |
| 163 if (!ReadSize(&blob_size) || data_len_ < (index_ + blob_size)) { |
| 164 value->reset(); |
| 165 return 0; |
| 166 } |
| 167 value->reset(new BlobReader(data_ + index_, blob_size)); |
| 168 index_ += blob_size; |
| 169 return true; |
| 170 } |
| 171 |
| 172 bool BlobReader::ReadString(std::string* value) { |
| 173 size_t length; |
| 174 if (!ReadSize(&length) || data_len_ < (index_ + length)) { |
| 175 value->erase(); |
| 176 return 0; |
| 177 } |
| 178 value->assign(reinterpret_cast<const char*>(data_ + index_), length); |
| 179 index_ += length; |
| 180 return true; |
| 181 } |
| 182 |
| 183 BlobWriter::BlobWriter() {} |
| 184 |
| 185 BlobWriter::~BlobWriter() {} |
| 186 |
| 187 void BlobWriter::WriteByte(uint8_t value) { data_.push_back(value); } |
| 188 |
| 189 void BlobWriter::WriteSize(size_t value) { |
| 190 data_.push_back((value & 0xff000000) >> 24); |
| 191 data_.push_back((value & 0xff0000) >> 16); |
| 192 data_.push_back((value & 0xff00) >> 8); |
| 193 data_.push_back(value & 0xff); |
| 194 } |
| 195 |
| 196 void BlobWriter::WriteBlobWriter(const BlobWriter& value) { |
| 197 WriteString(value.GetData()); |
| 198 } |
| 199 |
| 200 void BlobWriter::WriteString(const std::string& value) { |
| 201 WriteSize(value.length()); |
| 202 data_.insert(data_.end(), value.begin(), value.end()); |
| 203 } |
| 204 |
| 205 std::string BlobWriter::GetData() const { |
| 206 return std::string(reinterpret_cast<const char*>(data_.data()), data_.size()); |
| 207 } |
| 208 |
| 209 } // namespace |
| 210 |
| 211 bool GetJsonFromGnubbyRequest(const char* data, |
| 212 int data_len, |
| 213 std::string* json) { |
| 214 json->empty(); |
| 215 |
| 216 BlobReader ssh_request(reinterpret_cast<const uint8_t*>(data), data_len); |
| 217 scoped_ptr<BlobReader> blob; |
| 218 if (!ssh_request.ReadBlobReader(&blob)) |
| 219 return false; |
| 220 |
| 221 uint8_t cmd = 0; |
| 222 uint8_t timeout = 0; |
| 223 size_t request_count = 0; |
| 224 bool result = blob->ReadByte(&cmd); |
| 225 result = result && blob->ReadByte(&timeout); |
| 226 result = result && blob->ReadSize(&request_count); |
| 227 if (!result || cmd != kSsh2AgentcGnubbySignRequest) |
| 228 return false; |
| 229 |
| 230 base::DictionaryValue request; |
| 231 request.SetString(kType, kSignRequest); |
| 232 request.SetInteger(kTimeout, timeout); |
| 233 |
| 234 base::ListValue* sign_requests = new base::ListValue(); |
| 235 request.Set(kSignData, sign_requests); |
| 236 |
| 237 for (unsigned int i = 0; i < request_count; ++i) { |
| 238 scoped_ptr<BlobReader> sign_request; |
| 239 std::string version; |
| 240 std::string challenge_hash; |
| 241 std::string origin_hash; |
| 242 std::string key_handle; |
| 243 |
| 244 if (!(blob->ReadBlobReader(&sign_request) && |
| 245 sign_request->ReadString(&version) && |
| 246 sign_request->ReadString(&challenge_hash) && |
| 247 sign_request->ReadString(&origin_hash) && |
| 248 sign_request->ReadString(&key_handle))) |
| 249 return false; |
| 250 |
| 251 std::string encoded_origin_hash; |
| 252 std::string encoded_challenge_hash; |
| 253 std::string encoded_key_handle; |
| 254 |
| 255 WebSafeBase64Encode(origin_hash, &encoded_origin_hash); |
| 256 WebSafeBase64Encode(challenge_hash, &encoded_challenge_hash); |
| 257 WebSafeBase64Encode(key_handle, &encoded_key_handle); |
| 258 |
| 259 base::DictionaryValue* request = new base::DictionaryValue(); |
| 260 request->SetString(kAppIdHash, encoded_origin_hash); |
| 261 request->SetString(kChallengeHash, encoded_challenge_hash); |
| 262 request->SetString(kKeyHandle, encoded_key_handle); |
| 263 request->SetString(kVersion, version); |
| 264 sign_requests->Append(request); |
| 265 } |
| 266 |
| 267 base::JSONWriter::Write(&request, json); |
| 268 return true; |
| 269 } |
| 270 |
| 271 void GetGnubbyResponseFromJson(const std::string& json, std::string* data) { |
| 272 data->erase(); |
| 273 |
| 274 scoped_ptr<base::Value> json_value(base::JSONReader::Read(json)); |
| 275 base::DictionaryValue* reply; |
| 276 if (json_value && json_value->GetAsDictionary(&reply)) { |
| 277 BlobWriter response; |
| 278 response.WriteByte(kSsh2AgentcGnubbySignResponse); |
| 279 |
| 280 int code; |
| 281 if (reply->GetInteger(kCode, &code) && code == 0) { |
| 282 response.WriteSize(code); |
| 283 |
| 284 std::string type; |
| 285 if (!(reply->GetString(kType, &type) && type == kSignReply)) { |
| 286 LOG(ERROR) << "Invalid type"; |
| 287 return; |
| 288 } |
| 289 |
| 290 base::DictionaryValue* reply_data; |
| 291 if (!reply->GetDictionary(kResponseData, &reply_data)) { |
| 292 LOG(ERROR) << "Invalid response data"; |
| 293 return; |
| 294 } |
| 295 |
| 296 BlobWriter tmp; |
| 297 std::string version; |
| 298 if (reply_data->GetString(kVersion, &version)) { |
| 299 tmp.WriteString(version); |
| 300 } else { |
| 301 tmp.WriteSize(0); |
| 302 } |
| 303 |
| 304 std::string challenge_hash; |
| 305 if (!DecodeDataFromDictionary( |
| 306 *reply_data, kChallengeHash, &challenge_hash)) { |
| 307 LOG(ERROR) << "Invalid challenge hash"; |
| 308 return; |
| 309 } |
| 310 tmp.WriteString(challenge_hash); |
| 311 |
| 312 std::string app_id_hash; |
| 313 if (!DecodeDataFromDictionary(*reply_data, kAppIdHash, &app_id_hash)) { |
| 314 LOG(ERROR) << "Invalid app id hash"; |
| 315 return; |
| 316 } |
| 317 tmp.WriteString(app_id_hash); |
| 318 |
| 319 std::string key_handle; |
| 320 if (!DecodeDataFromDictionary(*reply_data, kKeyHandle, &key_handle)) { |
| 321 LOG(ERROR) << "Invalid key handle"; |
| 322 return; |
| 323 } |
| 324 tmp.WriteString(key_handle); |
| 325 |
| 326 std::string signature_data; |
| 327 if (!DecodeDataFromDictionary( |
| 328 *reply_data, kSignatureData, &signature_data)) { |
| 329 LOG(ERROR) << "Invalid signature data"; |
| 330 return; |
| 331 } |
| 332 tmp.WriteString(signature_data); |
| 333 |
| 334 response.WriteBlobWriter(tmp); |
| 335 } else { |
| 336 response.WriteSize(kGnubbyResponseFail); |
| 337 } |
| 338 |
| 339 BlobWriter ssh_response; |
| 340 ssh_response.WriteBlobWriter(response); |
| 341 data->assign(ssh_response.GetData()); |
| 342 } else { |
| 343 LOG(ERROR) << "Could not parse json: " << json; |
| 344 } |
| 345 } |
| 346 |
| 347 } // namespace remoting |
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