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1 // Copyright 2014 The Chromium Authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "components/network_time/network_time_tracker.h" | 5 #include "components/network_time/network_time_tracker.h" |
6 | 6 |
7 #include <stdint.h> | 7 #include <stdint.h> |
8 #include <utility> | 8 #include <utility> |
9 | 9 |
10 #include "base/i18n/time_formatting.h" | 10 #include "base/i18n/time_formatting.h" |
11 #include "base/json/json_reader.h" | |
11 #include "base/logging.h" | 12 #include "base/logging.h" |
12 #include "base/strings/utf_string_conversions.h" | 13 #include "base/strings/utf_string_conversions.h" |
13 #include "base/time/tick_clock.h" | 14 #include "base/time/tick_clock.h" |
14 #include "build/build_config.h" | 15 #include "build/build_config.h" |
16 #include "components/client_update_protocol/ecdsa.h" | |
15 #include "components/network_time/network_time_pref_names.h" | 17 #include "components/network_time/network_time_pref_names.h" |
16 #include "components/prefs/pref_registry_simple.h" | 18 #include "components/prefs/pref_registry_simple.h" |
17 #include "components/prefs/pref_service.h" | 19 #include "components/prefs/pref_service.h" |
20 #include "net/base/load_flags.h" | |
21 #include "net/http/http_response_headers.h" | |
22 #include "net/url_request/url_fetcher.h" | |
23 #include "url/gurl.h" | |
18 | 24 |
19 namespace network_time { | 25 namespace network_time { |
20 | 26 |
21 namespace { | 27 namespace { |
22 | 28 |
29 // Minimum number of minutes between time queries. | |
30 const uint32_t kMinimumQueryDelayMinutes = 60; | |
31 | |
23 // Number of time measurements performed in a given network time calculation. | 32 // Number of time measurements performed in a given network time calculation. |
24 const uint32_t kNumTimeMeasurements = 7; | 33 const uint32_t kNumTimeMeasurements = 7; |
25 | 34 |
26 // Amount of divergence allowed between wall clock and tick clock. | 35 // Amount of divergence allowed between wall clock and tick clock. |
27 const uint32_t kClockDivergenceSeconds = 60; | 36 const uint32_t kClockDivergenceSeconds = 60; |
28 | 37 |
29 // Maximum time lapse before deserialized data are considered stale. | 38 // Maximum time lapse before deserialized data are considered stale. |
30 const uint32_t kSerializedDataMaxAgeDays = 7; | 39 const uint32_t kSerializedDataMaxAgeDays = 7; |
31 | 40 |
32 // Name of a pref that stores the wall clock time, via |ToJsTime|. | 41 // Name of a pref that stores the wall clock time, via |ToJsTime|. |
33 const char kPrefTime[] = "local"; | 42 const char kPrefTime[] = "local"; |
34 | 43 |
35 // Name of a pref that stores the tick clock time, via |ToInternalValue|. | 44 // Name of a pref that stores the tick clock time, via |ToInternalValue|. |
36 const char kPrefTicks[] = "ticks"; | 45 const char kPrefTicks[] = "ticks"; |
37 | 46 |
38 // Name of a pref that stores the time uncertainty, via |ToInternalValue|. | 47 // Name of a pref that stores the time uncertainty, via |ToInternalValue|. |
39 const char kPrefUncertainty[] = "uncertainty"; | 48 const char kPrefUncertainty[] = "uncertainty"; |
40 | 49 |
41 // Name of a pref that stores the network time via |ToJsTime|. | 50 // Name of a pref that stores the network time via |ToJsTime|. |
42 const char kPrefNetworkTime[] = "network"; | 51 const char kPrefNetworkTime[] = "network"; |
43 | 52 |
53 // Time server's maximum allowable clock skew, in seconds. | |
54 const uint32_t kTimeServerMaxSkewSeconds = 10; | |
55 | |
56 const char kTimeServiceURL[] = "http://clients2.google.com/time/1/current"; | |
mmenke
2016/04/28 15:17:09
I thought there was a plan to move most google dom
mab
2016/04/29 19:42:07
I'll have to defer to waffles on the HSTS question
waffles
2016/04/29 19:51:22
mmenke: Please contact me (internally) with any ne
mmenke
2016/04/29 19:59:44
You're probably more knowledgeable here than I am.
| |
57 | |
58 // This is an ECDSA prime256v1 named-curve key. | |
59 const int kKeyVersion = 1; | |
60 const uint8_t kKeyPubBytes[] = { | |
61 0x30, 0x59, 0x30, 0x13, 0x06, 0x07, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x02, | |
62 0x01, 0x06, 0x08, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x03, 0x01, 0x07, 0x03, | |
63 0x42, 0x00, 0x04, 0xeb, 0xd8, 0xad, 0x0b, 0x8f, 0x75, 0xe8, 0x84, 0x36, | |
64 0x23, 0x48, 0x14, 0x24, 0xd3, 0x93, 0x42, 0x25, 0x43, 0xc1, 0xde, 0x36, | |
65 0x29, 0xc6, 0x95, 0xca, 0xeb, 0x28, 0x85, 0xff, 0x09, 0xdc, 0x08, 0xec, | |
66 0x45, 0x74, 0x6e, 0x4b, 0xc3, 0xa5, 0xfd, 0x8a, 0x2f, 0x02, 0xa0, 0x4b, | |
67 0xc3, 0xc6, 0xa4, 0x7b, 0xa4, 0x41, 0xfc, 0xa7, 0x02, 0x54, 0xab, 0xe3, | |
68 0xe4, 0xb1, 0x00, 0xf5, 0xd5, 0x09, 0x11}; | |
69 | |
70 std::string GetServerProof(const net::URLFetcher* source) { | |
71 const net::HttpResponseHeaders* response_headers = | |
72 source->GetResponseHeaders(); | |
73 if (!response_headers) { | |
74 return std::string(); | |
75 } | |
76 std::string proof; | |
77 return response_headers->EnumerateHeader(nullptr, "x-cup-server-proof", | |
78 &proof) | |
79 ? proof | |
80 : std::string(); | |
81 } | |
82 | |
44 } // namespace | 83 } // namespace |
45 | 84 |
46 // static | 85 // static |
47 void NetworkTimeTracker::RegisterPrefs(PrefRegistrySimple* registry) { | 86 void NetworkTimeTracker::RegisterPrefs(PrefRegistrySimple* registry) { |
48 registry->RegisterDictionaryPref(prefs::kNetworkTimeMapping, | 87 registry->RegisterDictionaryPref(prefs::kNetworkTimeMapping, |
49 new base::DictionaryValue()); | 88 new base::DictionaryValue()); |
50 } | 89 } |
51 | 90 |
52 NetworkTimeTracker::NetworkTimeTracker( | 91 NetworkTimeTracker::NetworkTimeTracker( |
53 std::unique_ptr<base::Clock> clock, | 92 std::unique_ptr<base::Clock> clock, |
54 std::unique_ptr<base::TickClock> tick_clock, | 93 std::unique_ptr<base::TickClock> tick_clock, |
55 PrefService* pref_service) | 94 PrefService* pref_service, |
56 : clock_(std::move(clock)), | 95 scoped_refptr<net::URLRequestContextGetter>& getter) |
96 : getter_(getter), | |
97 clock_(std::move(clock)), | |
57 tick_clock_(std::move(tick_clock)), | 98 tick_clock_(std::move(tick_clock)), |
58 pref_service_(pref_service) { | 99 pref_service_(pref_service) { |
59 const base::DictionaryValue* time_mapping = | 100 const base::DictionaryValue* time_mapping = |
60 pref_service_->GetDictionary(prefs::kNetworkTimeMapping); | 101 pref_service_->GetDictionary(prefs::kNetworkTimeMapping); |
61 double time_js = 0; | 102 double time_js = 0; |
62 double ticks_js = 0; | 103 double ticks_js = 0; |
63 double network_time_js = 0; | 104 double network_time_js = 0; |
64 double uncertainty_js = 0; | 105 double uncertainty_js = 0; |
65 if (time_mapping->GetDouble(kPrefTime, &time_js) && | 106 if (time_mapping->GetDouble(kPrefTime, &time_js) && |
66 time_mapping->GetDouble(kPrefTicks, &ticks_js) && | 107 time_mapping->GetDouble(kPrefTicks, &ticks_js) && |
67 time_mapping->GetDouble(kPrefUncertainty, &uncertainty_js) && | 108 time_mapping->GetDouble(kPrefUncertainty, &uncertainty_js) && |
68 time_mapping->GetDouble(kPrefNetworkTime, &network_time_js)) { | 109 time_mapping->GetDouble(kPrefNetworkTime, &network_time_js)) { |
69 time_at_last_measurement_ = base::Time::FromJsTime(time_js); | 110 time_at_last_measurement_ = base::Time::FromJsTime(time_js); |
70 ticks_at_last_measurement_ = base::TimeTicks::FromInternalValue( | 111 ticks_at_last_measurement_ = base::TimeTicks::FromInternalValue( |
71 static_cast<int64_t>(ticks_js)); | 112 static_cast<int64_t>(ticks_js)); |
72 network_time_uncertainty_ = base::TimeDelta::FromInternalValue( | 113 network_time_uncertainty_ = base::TimeDelta::FromInternalValue( |
73 static_cast<int64_t>(uncertainty_js)); | 114 static_cast<int64_t>(uncertainty_js)); |
74 network_time_at_last_measurement_ = base::Time::FromJsTime(network_time_js); | 115 network_time_at_last_measurement_ = base::Time::FromJsTime(network_time_js); |
75 } | 116 } |
76 base::Time now = clock_->Now(); | 117 base::Time now = clock_->Now(); |
77 if (ticks_at_last_measurement_ > tick_clock_->NowTicks() || | 118 if (ticks_at_last_measurement_ > tick_clock_->NowTicks() || |
78 time_at_last_measurement_ > now || | 119 time_at_last_measurement_ > now || |
79 now - time_at_last_measurement_ > | 120 now - time_at_last_measurement_ > |
80 base::TimeDelta::FromDays(kSerializedDataMaxAgeDays)) { | 121 base::TimeDelta::FromDays(kSerializedDataMaxAgeDays)) { |
81 // Drop saved mapping if either clock has run backward, or the data are too | 122 // Drop saved mapping if either clock has run backward, or the data are too |
82 // old. | 123 // old. |
83 pref_service_->ClearPref(prefs::kNetworkTimeMapping); | 124 pref_service_->ClearPref(prefs::kNetworkTimeMapping); |
84 network_time_at_last_measurement_ = base::Time(); // Reset. | 125 network_time_at_last_measurement_ = base::Time(); // Reset. |
85 } | 126 } |
127 | |
128 base::StringPiece public_key = {reinterpret_cast<const char*>(kKeyPubBytes), | |
129 sizeof(kKeyPubBytes)}; | |
130 | |
131 if (getter_) { | |
132 query_signer_ = | |
133 client_update_protocol::Ecdsa::Create(kKeyVersion, public_key); | |
134 base::TimeDelta period = | |
135 base::TimeDelta::FromMinutes(kMinimumQueryDelayMinutes); | |
136 query_timer_.Start(FROM_HERE, period, this, | |
137 &NetworkTimeTracker::QueryTimeService); | |
138 } | |
86 } | 139 } |
87 | 140 |
88 NetworkTimeTracker::~NetworkTimeTracker() { | 141 NetworkTimeTracker::~NetworkTimeTracker() { |
89 DCHECK(thread_checker_.CalledOnValidThread()); | 142 DCHECK(thread_checker_.CalledOnValidThread()); |
90 } | 143 } |
91 | 144 |
145 void NetworkTimeTracker::QueryTimeService() { | |
146 DCHECK(thread_checker_.CalledOnValidThread()); | |
147 | |
148 // If GetNetworkTime() returns true, the NetworkTimeTracker thinks it is in | |
149 // sync, so there is no need to query. | |
150 base::Time network_time; | |
151 if (GetNetworkTime(&network_time, nullptr)) { | |
152 return; | |
153 } | |
154 | |
155 std::string query_string; | |
156 query_signer_->SignRequest(nullptr, &query_string); | |
157 GURL url(kTimeServiceURL); | |
158 GURL::Replacements replacements; | |
159 replacements.SetQueryStr(query_string); | |
160 url = url.ReplaceComponents(replacements); | |
161 | |
162 // This cancels any outstanding fetch. | |
163 time_fetcher_ = net::URLFetcher::Create(url, net::URLFetcher::GET, this); | |
164 if (!time_fetcher_) { | |
165 DVLOG(1) << "tried to make fetch happen; failed"; | |
166 return; | |
167 } | |
168 time_fetcher_->SetRequestContext(getter_.get()); | |
169 // Not expecting any cookies, but just in case. | |
170 time_fetcher_->SetLoadFlags(net::LOAD_BYPASS_CACHE | net::LOAD_DISABLE_CACHE | | |
171 net::LOAD_DO_NOT_SAVE_COOKIES | | |
172 net::LOAD_DO_NOT_SEND_COOKIES | | |
173 net::LOAD_DO_NOT_SEND_AUTH_DATA); | |
174 time_fetcher_->Start(); | |
175 fetch_started_ = tick_clock_->NowTicks(); | |
176 } | |
177 | |
178 void NetworkTimeTracker::OnURLFetchComplete(const net::URLFetcher* source) { | |
179 DCHECK(thread_checker_.CalledOnValidThread()); | |
180 DCHECK(source); | |
181 if (source->GetStatus().status() != net::URLRequestStatus::SUCCESS && | |
182 source->GetResponseCode() != 200) { | |
183 DVLOG(1) << "fetch failed, status=" << source->GetStatus().status() | |
184 << ",code=" << source->GetResponseCode(); | |
185 return; | |
186 } | |
187 | |
188 std::string response_body; | |
189 if (!source->GetResponseAsString(&response_body)) { | |
190 DVLOG(1) << "failed to get response"; | |
191 return; | |
192 } | |
193 DCHECK(query_signer_); | |
194 if (!query_signer_->ValidateResponse(response_body, GetServerProof(source))) { | |
195 DVLOG(1) << "invalid signature"; | |
196 return; | |
197 } | |
198 response_body = response_body.substr(5); // Skips leading )]}'\n | |
199 base::JSONReader reader; | |
200 std::unique_ptr<base::Value> value = reader.Read(response_body); | |
201 if (!value) { | |
202 DVLOG(1) << "bad JSON"; | |
203 return; | |
204 } | |
205 const base::DictionaryValue* dict; | |
206 if (!value->GetAsDictionary(&dict)) { | |
207 DVLOG(1) << "not a dictionary"; | |
208 return; | |
209 } | |
210 double current_time_millis; | |
211 if (!dict->GetDouble("current_time_millis", ¤t_time_millis)) { | |
212 DVLOG(1) << "no current_time_millis"; | |
213 return; | |
214 } | |
215 // There is a "server_nonce" key here too, but it serves no purpose other than | |
216 // to make the server's response unpredictable. | |
217 base::Time current_time = base::Time::FromJsTime(current_time_millis); | |
218 // The extra 10 seconds comes from a property of the time server that we | |
219 // happen to know, which is its maximum allowable clock skew. It's unlikely | |
220 // that it would ever be that badly wrong, but all the same it's included here | |
221 // to document the very rough nature of the time service provided by this | |
222 // class. | |
223 base::TimeDelta resolution = | |
224 base::TimeDelta::FromMilliseconds(1) + | |
225 base::TimeDelta::FromSeconds(kTimeServerMaxSkewSeconds); | |
226 base::TimeDelta latency = tick_clock_->NowTicks() - fetch_started_; | |
227 UpdateNetworkTime(current_time, resolution, latency, tick_clock_->NowTicks()); | |
228 } | |
229 | |
92 void NetworkTimeTracker::UpdateNetworkTime(base::Time network_time, | 230 void NetworkTimeTracker::UpdateNetworkTime(base::Time network_time, |
93 base::TimeDelta resolution, | 231 base::TimeDelta resolution, |
94 base::TimeDelta latency, | 232 base::TimeDelta latency, |
95 base::TimeTicks post_time) { | 233 base::TimeTicks post_time) { |
96 DCHECK(thread_checker_.CalledOnValidThread()); | 234 DCHECK(thread_checker_.CalledOnValidThread()); |
97 DVLOG(1) << "Network time updating to " | 235 DVLOG(1) << "Network time updating to " |
98 << base::UTF16ToUTF8( | 236 << base::UTF16ToUTF8( |
99 base::TimeFormatFriendlyDateAndTime(network_time)); | 237 base::TimeFormatFriendlyDateAndTime(network_time)); |
100 // Update network time on every request to limit dependency on ticks lag. | 238 // Update network time on every request to limit dependency on ticks lag. |
101 // TODO(mad): Find a heuristic to avoid augmenting the | 239 // TODO(mad): Find a heuristic to avoid augmenting the |
(...skipping 23 matching lines...) Expand all Loading... | |
125 | 263 |
126 base::DictionaryValue time_mapping; | 264 base::DictionaryValue time_mapping; |
127 time_mapping.SetDouble(kPrefTime, time_at_last_measurement_.ToJsTime()); | 265 time_mapping.SetDouble(kPrefTime, time_at_last_measurement_.ToJsTime()); |
128 time_mapping.SetDouble(kPrefTicks, static_cast<double>( | 266 time_mapping.SetDouble(kPrefTicks, static_cast<double>( |
129 ticks_at_last_measurement_.ToInternalValue())); | 267 ticks_at_last_measurement_.ToInternalValue())); |
130 time_mapping.SetDouble(kPrefUncertainty, static_cast<double>( | 268 time_mapping.SetDouble(kPrefUncertainty, static_cast<double>( |
131 network_time_uncertainty_.ToInternalValue())); | 269 network_time_uncertainty_.ToInternalValue())); |
132 time_mapping.SetDouble(kPrefNetworkTime, | 270 time_mapping.SetDouble(kPrefNetworkTime, |
133 network_time_at_last_measurement_.ToJsTime()); | 271 network_time_at_last_measurement_.ToJsTime()); |
134 pref_service_->Set(prefs::kNetworkTimeMapping, time_mapping); | 272 pref_service_->Set(prefs::kNetworkTimeMapping, time_mapping); |
273 | |
274 if (getter_) { | |
275 query_timer_.Reset(); | |
276 } | |
135 } | 277 } |
136 | 278 |
137 bool NetworkTimeTracker::GetNetworkTime(base::Time* network_time, | 279 bool NetworkTimeTracker::GetNetworkTime(base::Time* network_time, |
138 base::TimeDelta* uncertainty) const { | 280 base::TimeDelta* uncertainty) const { |
139 DCHECK(thread_checker_.CalledOnValidThread()); | 281 DCHECK(thread_checker_.CalledOnValidThread()); |
140 DCHECK(network_time); | 282 DCHECK(network_time); |
141 if (network_time_at_last_measurement_.is_null()) { | 283 if (network_time_at_last_measurement_.is_null()) { |
142 return false; | 284 return false; |
143 } | 285 } |
144 DCHECK(!ticks_at_last_measurement_.is_null()); | 286 DCHECK(!ticks_at_last_measurement_.is_null()); |
(...skipping 16 matching lines...) Expand all Loading... | |
161 return false; | 303 return false; |
162 } | 304 } |
163 *network_time = network_time_at_last_measurement_ + tick_delta; | 305 *network_time = network_time_at_last_measurement_ + tick_delta; |
164 if (uncertainty) { | 306 if (uncertainty) { |
165 *uncertainty = network_time_uncertainty_ + divergence; | 307 *uncertainty = network_time_uncertainty_ + divergence; |
166 } | 308 } |
167 return true; | 309 return true; |
168 } | 310 } |
169 | 311 |
170 } // namespace network_time | 312 } // namespace network_time |
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