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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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