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 "google_apis/gaia/oauth2_access_token_fetcher_impl.h"
6
7#include <algorithm>
8#include <string>
9#include <vector>
10
11#include "base/json/json_reader.h"
12#include "base/metrics/histogram.h"
13#include "base/metrics/sparse_histogram.h"
14#include "base/strings/string_util.h"
15#include "base/strings/stringprintf.h"
16#include "base/time/time.h"
17#include "base/values.h"
18#include "google_apis/gaia/gaia_urls.h"
19#include "google_apis/gaia/google_service_auth_error.h"
20#include "net/base/escape.h"
21#include "net/base/load_flags.h"
22#include "net/http/http_status_code.h"
23#include "net/url_request/url_fetcher.h"
24#include "net/url_request/url_request_context_getter.h"
25#include "net/url_request/url_request_status.h"
26
27using net::ResponseCookies;
28using net::URLFetcher;
29using net::URLFetcherDelegate;
30using net::URLRequestContextGetter;
31using net::URLRequestStatus;
32
33namespace {
34static const char kGetAccessTokenBodyFormat[] =
35    "client_id=%s&"
36    "client_secret=%s&"
37    "grant_type=refresh_token&"
38    "refresh_token=%s";
39
40static const char kGetAccessTokenBodyWithScopeFormat[] =
41    "client_id=%s&"
42    "client_secret=%s&"
43    "grant_type=refresh_token&"
44    "refresh_token=%s&"
45    "scope=%s";
46
47static const char kAccessTokenKey[] = "access_token";
48static const char kExpiresInKey[] = "expires_in";
49static const char kErrorKey[] = "error";
50
51// Enumerated constants for logging server responses on 400 errors, matching
52// RFC 6749.
53enum OAuth2ErrorCodesForHistogram {
54  OAUTH2_ACCESS_ERROR_INVALID_REQUEST = 0,
55  OAUTH2_ACCESS_ERROR_INVALID_CLIENT,
56  OAUTH2_ACCESS_ERROR_INVALID_GRANT,
57  OAUTH2_ACCESS_ERROR_UNAUTHORIZED_CLIENT,
58  OAUTH2_ACCESS_ERROR_UNSUPPORTED_GRANT_TYPE,
59  OAUTH2_ACCESS_ERROR_INVALID_SCOPE,
60  OAUTH2_ACCESS_ERROR_UNKNOWN,
61  OAUTH2_ACCESS_ERROR_COUNT
62};
63
64OAuth2ErrorCodesForHistogram OAuth2ErrorToHistogramValue(
65    const std::string& error) {
66  if (error == "invalid_request")
67    return OAUTH2_ACCESS_ERROR_INVALID_REQUEST;
68  else if (error == "invalid_client")
69    return OAUTH2_ACCESS_ERROR_INVALID_CLIENT;
70  else if (error == "invalid_grant")
71    return OAUTH2_ACCESS_ERROR_INVALID_GRANT;
72  else if (error == "unauthorized_client")
73    return OAUTH2_ACCESS_ERROR_UNAUTHORIZED_CLIENT;
74  else if (error == "unsupported_grant_type")
75    return OAUTH2_ACCESS_ERROR_UNSUPPORTED_GRANT_TYPE;
76  else if (error == "invalid_scope")
77    return OAUTH2_ACCESS_ERROR_INVALID_SCOPE;
78
79  return OAUTH2_ACCESS_ERROR_UNKNOWN;
80}
81
82static GoogleServiceAuthError CreateAuthError(URLRequestStatus status) {
83  CHECK(!status.is_success());
84  if (status.status() == URLRequestStatus::CANCELED) {
85    return GoogleServiceAuthError(GoogleServiceAuthError::REQUEST_CANCELED);
86  } else {
87    DLOG(WARNING) << "Could not reach Google Accounts servers: errno "
88                  << status.error();
89    return GoogleServiceAuthError::FromConnectionError(status.error());
90  }
91}
92
93static URLFetcher* CreateFetcher(URLRequestContextGetter* getter,
94                                 const GURL& url,
95                                 const std::string& body,
96                                 URLFetcherDelegate* delegate) {
97  bool empty_body = body.empty();
98  URLFetcher* result = net::URLFetcher::Create(
99      0, url, empty_body ? URLFetcher::GET : URLFetcher::POST, delegate);
100
101  result->SetRequestContext(getter);
102  result->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
103                       net::LOAD_DO_NOT_SAVE_COOKIES);
104  // Fetchers are sometimes cancelled because a network change was detected,
105  // especially at startup and after sign-in on ChromeOS. Retrying once should
106  // be enough in those cases; let the fetcher retry up to 3 times just in case.
107  // http://crbug.com/163710
108  result->SetAutomaticallyRetryOnNetworkChanges(3);
109
110  if (!empty_body)
111    result->SetUploadData("application/x-www-form-urlencoded", body);
112
113  return result;
114}
115
116scoped_ptr<base::DictionaryValue> ParseGetAccessTokenResponse(
117    const net::URLFetcher* source) {
118  CHECK(source);
119
120  std::string data;
121  source->GetResponseAsString(&data);
122  scoped_ptr<base::Value> value(base::JSONReader::Read(data));
123  if (!value.get() || value->GetType() != base::Value::TYPE_DICTIONARY)
124    value.reset();
125
126  return scoped_ptr<base::DictionaryValue>(
127      static_cast<base::DictionaryValue*>(value.release()));
128}
129
130}  // namespace
131
132OAuth2AccessTokenFetcherImpl::OAuth2AccessTokenFetcherImpl(
133    OAuth2AccessTokenConsumer* consumer,
134    net::URLRequestContextGetter* getter,
135    const std::string& refresh_token)
136    : OAuth2AccessTokenFetcher(consumer),
137      getter_(getter),
138      refresh_token_(refresh_token),
139      state_(INITIAL) {}
140
141OAuth2AccessTokenFetcherImpl::~OAuth2AccessTokenFetcherImpl() {}
142
143void OAuth2AccessTokenFetcherImpl::CancelRequest() { fetcher_.reset(); }
144
145void OAuth2AccessTokenFetcherImpl::Start(
146    const std::string& client_id,
147    const std::string& client_secret,
148    const std::vector<std::string>& scopes) {
149  client_id_ = client_id;
150  client_secret_ = client_secret;
151  scopes_ = scopes;
152  StartGetAccessToken();
153}
154
155void OAuth2AccessTokenFetcherImpl::StartGetAccessToken() {
156  CHECK_EQ(INITIAL, state_);
157  state_ = GET_ACCESS_TOKEN_STARTED;
158  fetcher_.reset(
159      CreateFetcher(getter_,
160                    MakeGetAccessTokenUrl(),
161                    MakeGetAccessTokenBody(
162                        client_id_, client_secret_, refresh_token_, scopes_),
163                    this));
164  fetcher_->Start();  // OnURLFetchComplete will be called.
165}
166
167void OAuth2AccessTokenFetcherImpl::EndGetAccessToken(
168    const net::URLFetcher* source) {
169  CHECK_EQ(GET_ACCESS_TOKEN_STARTED, state_);
170  state_ = GET_ACCESS_TOKEN_DONE;
171
172  URLRequestStatus status = source->GetStatus();
173  int histogram_value =
174      status.is_success() ? source->GetResponseCode() : status.error();
175  UMA_HISTOGRAM_SPARSE_SLOWLY("Gaia.ResponseCodesForOAuth2AccessToken",
176                              histogram_value);
177  if (!status.is_success()) {
178    OnGetTokenFailure(CreateAuthError(status));
179    return;
180  }
181
182  switch (source->GetResponseCode()) {
183    case net::HTTP_OK:
184      break;
185    case net::HTTP_FORBIDDEN:
186      // HTTP_FORBIDDEN (403) is treated as temporary error, because it may be
187      // '403 Rate Limit Exeeded.'
188      OnGetTokenFailure(
189          GoogleServiceAuthError(GoogleServiceAuthError::SERVICE_UNAVAILABLE));
190      return;
191    case net::HTTP_BAD_REQUEST: {
192      // HTTP_BAD_REQUEST (400) usually contains error as per
193      // http://tools.ietf.org/html/rfc6749#section-5.2.
194      std::string gaia_error;
195      if (!ParseGetAccessTokenFailureResponse(source, &gaia_error)) {
196        OnGetTokenFailure(
197            GoogleServiceAuthError(GoogleServiceAuthError::SERVICE_ERROR));
198        return;
199      }
200
201      OAuth2ErrorCodesForHistogram access_error(
202          OAuth2ErrorToHistogramValue(gaia_error));
203      UMA_HISTOGRAM_ENUMERATION("Gaia.BadRequestTypeForOAuth2AccessToken",
204                                access_error,
205                                OAUTH2_ACCESS_ERROR_COUNT);
206
207      OnGetTokenFailure(
208          access_error == OAUTH2_ACCESS_ERROR_INVALID_GRANT
209              ? GoogleServiceAuthError(
210                    GoogleServiceAuthError::INVALID_GAIA_CREDENTIALS)
211              : GoogleServiceAuthError(GoogleServiceAuthError::SERVICE_ERROR));
212      return;
213    }
214    default: {
215      if (source->GetResponseCode() >= net::HTTP_INTERNAL_SERVER_ERROR) {
216        // 5xx is always treated as transient.
217        OnGetTokenFailure(GoogleServiceAuthError(
218            GoogleServiceAuthError::SERVICE_UNAVAILABLE));
219      } else {
220        // The other errors are treated as permanent error.
221        DLOG(ERROR) << "Unexpected persistent error: http_status="
222                    << source->GetResponseCode();
223        OnGetTokenFailure(GoogleServiceAuthError(
224            GoogleServiceAuthError::INVALID_GAIA_CREDENTIALS));
225      }
226      return;
227    }
228  }
229
230  // The request was successfully fetched and it returned OK.
231  // Parse out the access token and the expiration time.
232  std::string access_token;
233  int expires_in;
234  if (!ParseGetAccessTokenSuccessResponse(source, &access_token, &expires_in)) {
235    DLOG(WARNING) << "Response doesn't match expected format";
236    OnGetTokenFailure(
237        GoogleServiceAuthError(GoogleServiceAuthError::SERVICE_UNAVAILABLE));
238    return;
239  }
240  // The token will expire in |expires_in| seconds. Take a 10% error margin to
241  // prevent reusing a token too close to its expiration date.
242  OnGetTokenSuccess(
243      access_token,
244      base::Time::Now() + base::TimeDelta::FromSeconds(9 * expires_in / 10));
245}
246
247void OAuth2AccessTokenFetcherImpl::OnGetTokenSuccess(
248    const std::string& access_token,
249    const base::Time& expiration_time) {
250  FireOnGetTokenSuccess(access_token, expiration_time);
251}
252
253void OAuth2AccessTokenFetcherImpl::OnGetTokenFailure(
254    const GoogleServiceAuthError& error) {
255  state_ = ERROR_STATE;
256  FireOnGetTokenFailure(error);
257}
258
259void OAuth2AccessTokenFetcherImpl::OnURLFetchComplete(
260    const net::URLFetcher* source) {
261  CHECK(source);
262  CHECK(state_ == GET_ACCESS_TOKEN_STARTED);
263  EndGetAccessToken(source);
264}
265
266// static
267GURL OAuth2AccessTokenFetcherImpl::MakeGetAccessTokenUrl() {
268  return GaiaUrls::GetInstance()->oauth2_token_url();
269}
270
271// static
272std::string OAuth2AccessTokenFetcherImpl::MakeGetAccessTokenBody(
273    const std::string& client_id,
274    const std::string& client_secret,
275    const std::string& refresh_token,
276    const std::vector<std::string>& scopes) {
277  std::string enc_client_id = net::EscapeUrlEncodedData(client_id, true);
278  std::string enc_client_secret =
279      net::EscapeUrlEncodedData(client_secret, true);
280  std::string enc_refresh_token =
281      net::EscapeUrlEncodedData(refresh_token, true);
282  if (scopes.empty()) {
283    return base::StringPrintf(kGetAccessTokenBodyFormat,
284                              enc_client_id.c_str(),
285                              enc_client_secret.c_str(),
286                              enc_refresh_token.c_str());
287  } else {
288    std::string scopes_string = JoinString(scopes, ' ');
289    return base::StringPrintf(
290        kGetAccessTokenBodyWithScopeFormat,
291        enc_client_id.c_str(),
292        enc_client_secret.c_str(),
293        enc_refresh_token.c_str(),
294        net::EscapeUrlEncodedData(scopes_string, true).c_str());
295  }
296}
297
298// static
299bool OAuth2AccessTokenFetcherImpl::ParseGetAccessTokenSuccessResponse(
300    const net::URLFetcher* source,
301    std::string* access_token,
302    int* expires_in) {
303  CHECK(access_token);
304  scoped_ptr<base::DictionaryValue> value = ParseGetAccessTokenResponse(source);
305  if (value.get() == NULL)
306    return false;
307
308  return value->GetString(kAccessTokenKey, access_token) &&
309         value->GetInteger(kExpiresInKey, expires_in);
310}
311
312// static
313bool OAuth2AccessTokenFetcherImpl::ParseGetAccessTokenFailureResponse(
314    const net::URLFetcher* source,
315    std::string* error) {
316  CHECK(error);
317  scoped_ptr<base::DictionaryValue> value = ParseGetAccessTokenResponse(source);
318  if (value.get() == NULL)
319    return false;
320  return value->GetString(kErrorKey, error);
321}
322