Check for embedded PAC scripts when migrating proxy pref for DRP.

chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.h"
 
 #include <string>
 
+#include "base/base64.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/prefs/pref_service.h"
 #include "base/prefs/scoped_user_pref_update.h"
 #include "base/strings/string_util.h"
 #include "base/time/time.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/metrics/chrome_metrics_service_accessor.h"
 #include "chrome/browser/prefs/proxy_prefs.h"
 #include "chrome/browser/profiles/profile.h"
@@ skipping 33 matching lines @@
 // Searches |proxy_rules| for any Data Reduction Proxies, even if they don't
 // match a currently configured Data Reduction Proxy.
 bool ContainsDataReductionProxyDefaultHostSuffix(
     const net::ProxyConfig::ProxyRules& proxy_rules) {
   return ContainsDataReductionProxyDefaultHostSuffix(
              proxy_rules.proxies_for_http) ||
          ContainsDataReductionProxyDefaultHostSuffix(
              proxy_rules.proxies_for_https);
 }
 
+// Extract the embedded |pac_script| from the given |pac_url|. Returns true if
+// extraction was successful, otherwise returns false.
+bool GetEmbeddedPacScript(const std::string& pac_url, std::string* pac_script) {

[bengr, 2015/06/08 18:26:33]

Can the pac_script be const? Can it ever be null?

[sclittle, 2015/06/08 18:47:45]

I've updated the comment to clarify that pac_script can't be null, and that the
extracted PAC script is stored in it.

+  const std::string kPacURLPrefix =
+      "data:application/x-ns-proxy-autoconfig;base64,";
+  return StartsWithASCII(pac_url, kPacURLPrefix, true) &&
+         base::Base64Decode(pac_url.substr(kPacURLPrefix.size()), pac_script);

[bengr, 2015/06/08 18:26:33]

Will the pac always be base64?

[sclittle, 2015/06/08 18:47:45]

Yes, according to the way that the DRP was enabled in M35-. Base64Decode will
return false if decoding is unsuccessful.

+}
+
 }  // namespace
 
 // The Data Reduction Proxy has been turned into a "best effort" proxy,
 // meaning it is used only if the effective proxy configuration resolves to
 // DIRECT for a URL. It no longer can be a ProxyConfig in the proxy preference
 // hierarchy. This method removes the Data Reduction Proxy configuration from
 // prefs, if present. |proxy_pref_name| is the name of the proxy pref.
 void DataReductionProxyChromeSettings::MigrateDataReductionProxyOffProxyPrefs(
     PrefService* prefs) {
   ProxyPrefMigrationResult proxy_pref_status =
       MigrateDataReductionProxyOffProxyPrefsHelper(prefs);
+  LOG(WARNING) << "MigrateDataReductionProxyOffProxyPrefs "
+               << proxy_pref_status;
   UMA_HISTOGRAM_ENUMERATION("DataReductionProxy.ProxyPrefMigrationResult",
                             proxy_pref_status,
                             DataReductionProxyChromeSettings::PROXY_PREF_MAX);
 }
 
 DataReductionProxyChromeSettings::ProxyPrefMigrationResult
 DataReductionProxyChromeSettings::MigrateDataReductionProxyOffProxyPrefsHelper(
     PrefService* prefs) {
   base::DictionaryValue* dict =
       (base::DictionaryValue*)prefs->GetUserPrefValue(prefs::kProxy);
   if (!dict)
     return PROXY_PREF_NOT_CLEARED;
 
   // Clear empty "proxy" dictionary created by a bug. See http://crbug/448172.
   if (dict->empty()) {
     prefs->ClearPref(prefs::kProxy);
     return PROXY_PREF_CLEARED_EMPTY;
   }
 
   std::string mode;
   if (!dict->GetString("mode", &mode))
     return PROXY_PREF_NOT_CLEARED;
   // Clear "system" proxy entry since this is the default. This entry was
   // created by bug (http://crbug/448172).
   if (ProxyModeToString(ProxyPrefs::MODE_SYSTEM) == mode) {
     prefs->ClearPref(prefs::kProxy);
     return PROXY_PREF_CLEARED_MODE_SYSTEM;
   }
-  if (ProxyModeToString(ProxyPrefs::MODE_FIXED_SERVERS) != mode)
-    return PROXY_PREF_NOT_CLEARED;
-  std::string proxy_server;
-  if (!dict->GetString("server", &proxy_server))
-    return PROXY_PREF_NOT_CLEARED;
-  net::ProxyConfig::ProxyRules proxy_rules;
-  proxy_rules.ParseFromString(proxy_server);
-  // Clear the proxy pref if it matches a currently configured Data Reduction
-  // Proxy, or if the proxy host ends with ".googlezip.net", in order to ensure
-  // that any DRP in the pref is cleared even if the DRP configuration was
-  // changed. See http://crbug.com/476610.
-  ProxyPrefMigrationResult rv;
-  if (Config()->ContainsDataReductionProxy(proxy_rules))
-    rv = PROXY_PREF_CLEARED_DRP;
-  else if (ContainsDataReductionProxyDefaultHostSuffix(proxy_rules))
-    rv = PROXY_PREF_CLEARED_GOOGLEZIP;
-  else
-    return PROXY_PREF_NOT_CLEARED;
 
-  prefs->ClearPref(prefs::kProxy);
-  return rv;
+  // From M36 to M40, the DRP was configured using MODE_FIXED_SERVERS in the
+  // proxy pref.
+  if (ProxyModeToString(ProxyPrefs::MODE_FIXED_SERVERS) == mode) {
+    std::string proxy_server;
+    if (!dict->GetString("server", &proxy_server))
+      return PROXY_PREF_NOT_CLEARED;
+    net::ProxyConfig::ProxyRules proxy_rules;
+    proxy_rules.ParseFromString(proxy_server);
+    // Clear the proxy pref if it matches a currently configured Data Reduction
+    // Proxy, or if the proxy host ends with ".googlezip.net", in order to
+    // ensure that any DRP in the pref is cleared even if the DRP configuration
+    // was changed. See http://crbug.com/476610.
+    ProxyPrefMigrationResult rv;
+    if (Config()->ContainsDataReductionProxy(proxy_rules))
+      rv = PROXY_PREF_CLEARED_DRP;
+    else if (ContainsDataReductionProxyDefaultHostSuffix(proxy_rules))
+      rv = PROXY_PREF_CLEARED_GOOGLEZIP;
+    else
+      return PROXY_PREF_NOT_CLEARED;
+
+    prefs->ClearPref(prefs::kProxy);
+    return rv;
+  }
+
+  // Before M35, the DRP was configured using a PAC script base64 encoded into a
+  // PAC url.
+  if (ProxyModeToString(ProxyPrefs::MODE_PAC_SCRIPT) == mode) {
+    std::string pac_url;
+    std::string pac_script;
+    if (!dict->GetString("pac_url", &pac_url) ||
+        !GetEmbeddedPacScript(pac_url, &pac_script)) {
+      return PROXY_PREF_NOT_CLEARED;
+    }
+
+    // In M35 and earlier, the way of specifying the DRP in a PAC script would
+    // always include the port number after the host even if the port number
+    // could be implied, so searching for ".googlezip.net:" in the PAC script
+    // indicates whether there's a proxy in that PAC script with a host of the
+    // form "*.googlezip.net".
+    if (pac_script.find(".googlezip.net:") == std::string::npos)
+      return PROXY_PREF_NOT_CLEARED;
+
+    prefs->ClearPref(prefs::kProxy);
+    return PROXY_PREF_CLEARED_PAC_GOOGLEZIP;
+  }
+
+  return PROXY_PREF_NOT_CLEARED;
 }
 
 DataReductionProxyChromeSettings::DataReductionProxyChromeSettings()
     : data_reduction_proxy::DataReductionProxySettings() {
 }
 
 DataReductionProxyChromeSettings::~DataReductionProxyChromeSettings() {
 }
 
 void DataReductionProxyChromeSettings::Shutdown() {
@@ skipping 59 matching lines @@
 #elif defined(OS_OPENBSD)
   return data_reduction_proxy::Client::CHROME_OPENBSD;
 #elif defined(OS_SOLARIS)
   return data_reduction_proxy::Client::CHROME_SOLARIS;
 #elif defined(OS_QNX)
   return data_reduction_proxy::Client::CHROME_QNX;
 #else
   return data_reduction_proxy::Client::UNKNOWN;
 #endif
 }