chrome/common/extensions/permissions/chrome_permission_message_provider.cc

   1 // Copyright 2013 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 "chrome/common/extensions/permissions/chrome_permission_message_provider.h"
   6
   7 #include <vector>
   8
   9 #include "base/memory/scoped_vector.h"
  10 #include "base/metrics/field_trial.h"
  11 #include "base/stl_util.h"
  12 #include "base/strings/string_util.h"
  13 #include "base/strings/stringprintf.h"
  14 #include "chrome/common/extensions/permissions/chrome_permission_message_rules.h"
  15 #include "chrome/grit/generated_resources.h"
  16 #include "extensions/common/extensions_client.h"
  17 #include "extensions/common/permissions/permission_message.h"
  18 #include "extensions/common/permissions/permission_message_util.h"
  19 #include "extensions/common/permissions/permission_set.h"
  20 #include "extensions/common/url_pattern.h"
  21 #include "extensions/common/url_pattern_set.h"
  22 #include "grit/extensions_strings.h"
  23 #include "ui/base/l10n/l10n_util.h"
  24 #include "url/gurl.h"
  25
  26 namespace extensions {
  27
  28 namespace {
  29
  30 // Copyable wrapper to make CoalescedPermissionMessages comparable.
  31 class ComparablePermission {
  32  public:
  33   explicit ComparablePermission(const CoalescedPermissionMessage& msg)
  34       : msg_(&msg) {}
  35
  36   bool operator<(const ComparablePermission& rhs) const {
  37     if (msg_->message() < rhs.msg_->message())
  38       return true;
  39     if (msg_->message() > rhs.msg_->message())
  40       return false;
  41     return msg_->submessages() < rhs.msg_->submessages();
  42   }
  43
  44  private:
  45   const CoalescedPermissionMessage* msg_;
  46 };
  47 using ComparablePermissions = std::vector<ComparablePermission>;
  48
  49 }  // namespace
  50
  51 typedef std::set<PermissionMessage> PermissionMsgSet;
  52
  53 ChromePermissionMessageProvider::ChromePermissionMessageProvider() {
  54 }
  55
  56 ChromePermissionMessageProvider::~ChromePermissionMessageProvider() {
  57 }
  58
  59 CoalescedPermissionMessages
  60 ChromePermissionMessageProvider::GetPermissionMessages(
  61     const PermissionIDSet& permissions) const {
  62   std::vector<ChromePermissionMessageRule> rules =
  63       ChromePermissionMessageRule::GetAllRules();
  64
  65   // Apply each of the rules, in order, to generate the messages for the given
  66   // permissions. Once a permission is used in a rule, remove it from the set
  67   // of available permissions so it cannot be applied to subsequent rules.
  68   PermissionIDSet remaining_permissions = permissions;
  69   CoalescedPermissionMessages messages;
  70   for (const auto& rule : rules) {
  71     // Only apply the rule if we have all the required permission IDs.
  72     if (remaining_permissions.ContainsAllIDs(rule.required_permissions())) {
  73       // We can apply the rule. Add all the required permissions, and as many
  74       // optional permissions as we can, to the new message.
  75       PermissionIDSet used_permissions =
  76           remaining_permissions.GetAllPermissionsWithIDs(
  77               rule.all_permissions());
  78       messages.push_back(rule.GetPermissionMessage(used_permissions));
  79
  80       remaining_permissions =
  81           PermissionIDSet::Difference(remaining_permissions, used_permissions);
  82     }
  83   }
  84
  85   return messages;
  86 }
  87
  88 bool ChromePermissionMessageProvider::IsPrivilegeIncrease(
  89     const PermissionSet* old_permissions,
  90     const PermissionSet* new_permissions,
  91     Manifest::Type extension_type) const {
  92   // Things can't get worse than native code access.
  93   if (old_permissions->HasEffectiveFullAccess())
  94     return false;
  95
  96   // Otherwise, it's a privilege increase if the new one has full access.
  97   if (new_permissions->HasEffectiveFullAccess())
  98     return true;
  99
 100   if (IsHostPrivilegeIncrease(old_permissions, new_permissions, extension_type))
 101     return true;
 102
 103   if (IsAPIPrivilegeIncrease(old_permissions, new_permissions))
 104     return true;
 105
 106   if (IsManifestPermissionPrivilegeIncrease(old_permissions, new_permissions))
 107     return true;
 108
 109   return false;
 110 }
 111
 112 PermissionIDSet ChromePermissionMessageProvider::GetAllPermissionIDs(
 113     const PermissionSet* permissions,
 114     Manifest::Type extension_type) const {
 115   PermissionIDSet permission_ids;
 116   AddAPIPermissions(permissions, &permission_ids);
 117   AddManifestPermissions(permissions, &permission_ids);
 118   AddHostPermissions(permissions, &permission_ids, extension_type);
 119   return permission_ids;
 120 }
 121
 122 void ChromePermissionMessageProvider::AddAPIPermissions(
 123     const PermissionSet* permissions,
 124     PermissionIDSet* permission_ids) const {
 125   for (const APIPermission* permission : permissions->apis())
 126     permission_ids->InsertAll(permission->GetPermissions());
 127
 128   // A special hack: The warning message for declarativeWebRequest
 129   // permissions speaks about blocking parts of pages, which is a
 130   // subset of what the "<all_urls>" access allows. Therefore we
 131   // display only the "<all_urls>" warning message if both permissions
 132   // are required.
 133   // TODO(treib): The same should apply to other permissions that are implied by
 134   // "<all_urls>" (aka APIPermission::kHostsAll), such as kTab. This would
 135   // happen automatically if we didn't differentiate between API/Manifest/Host
 136   // permissions here.
 137   if (permissions->ShouldWarnAllHosts())
 138     permission_ids->erase(APIPermission::kDeclarativeWebRequest);
 139 }
 140
 141 void ChromePermissionMessageProvider::AddManifestPermissions(
 142     const PermissionSet* permissions,
 143     PermissionIDSet* permission_ids) const {
 144   for (const ManifestPermission* p : permissions->manifest_permissions())
 145     permission_ids->InsertAll(p->GetPermissions());
 146 }
 147
 148 void ChromePermissionMessageProvider::AddHostPermissions(
 149     const PermissionSet* permissions,
 150     PermissionIDSet* permission_ids,
 151     Manifest::Type extension_type) const {
 152   // Since platform apps always use isolated storage, they can't (silently)
 153   // access user data on other domains, so there's no need to prompt.
 154   // Note: this must remain consistent with IsHostPrivilegeIncrease.
 155   // See crbug.com/255229.
 156   if (extension_type == Manifest::TYPE_PLATFORM_APP)
 157     return;
 158
 159   if (permissions->ShouldWarnAllHosts()) {
 160     permission_ids->insert(APIPermission::kHostsAll);
 161   } else {
 162     URLPatternSet regular_hosts;
 163     ExtensionsClient::Get()->FilterHostPermissions(
 164         permissions->effective_hosts(), &regular_hosts, permission_ids);
 165
 166     std::set<std::string> hosts =
 167         permission_message_util::GetDistinctHosts(regular_hosts, true, true);
 168     if (!hosts.empty()) {
 169       permission_message_util::AddHostPermissions(
 170           permission_ids, hosts, permission_message_util::kReadWrite);
 171     }
 172   }
 173 }
 174
 175 bool ChromePermissionMessageProvider::IsAPIPrivilegeIncrease(
 176     const PermissionSet* old_permissions,
 177     const PermissionSet* new_permissions) const {
 178   PermissionIDSet old_ids;
 179   AddAPIPermissions(old_permissions, &old_ids);
 180   PermissionIDSet new_ids;
 181   AddAPIPermissions(new_permissions, &new_ids);
 182
 183   // A special hack: kFileSystemWriteDirectory implies kFileSystemDirectory.
 184   // TODO(sammc): Remove this. See http://crbug.com/284849.
 185   if (old_ids.ContainsID(APIPermission::kFileSystemWriteDirectory))
 186     old_ids.insert(APIPermission::kFileSystemDirectory);
 187
 188   return IsAPIOrManifestPrivilegeIncrease(old_ids, new_ids);
 189 }
 190
 191 bool ChromePermissionMessageProvider::IsManifestPermissionPrivilegeIncrease(
 192     const PermissionSet* old_permissions,
 193     const PermissionSet* new_permissions) const {
 194   PermissionIDSet old_ids;
 195   AddManifestPermissions(old_permissions, &old_ids);
 196   PermissionIDSet new_ids;
 197   AddManifestPermissions(new_permissions, &new_ids);
 198
 199   return IsAPIOrManifestPrivilegeIncrease(old_ids, new_ids);
 200 }
 201
 202 bool ChromePermissionMessageProvider::IsAPIOrManifestPrivilegeIncrease(
 203     const PermissionIDSet& old_ids,
 204     const PermissionIDSet& new_ids) const {
 205   // If all the IDs were already there, it's not a privilege increase.
 206   if (old_ids.Includes(new_ids))
 207     return false;
 208
 209   // Otherwise, check the actual messages - not all IDs result in a message,
 210   // and some messages can suppress others.
 211   CoalescedPermissionMessages old_messages = GetPermissionMessages(old_ids);
 212   CoalescedPermissionMessages new_messages = GetPermissionMessages(new_ids);
 213
 214   ComparablePermissions old_strings(old_messages.begin(), old_messages.end());
 215   ComparablePermissions new_strings(new_messages.begin(), new_messages.end());
 216
 217   std::sort(old_strings.begin(), old_strings.end());
 218   std::sort(new_strings.begin(), new_strings.end());
 219
 220   return !base::STLIncludes(old_strings, new_strings);
 221 }
 222
 223 bool ChromePermissionMessageProvider::IsHostPrivilegeIncrease(
 224     const PermissionSet* old_permissions,
 225     const PermissionSet* new_permissions,
 226     Manifest::Type extension_type) const {
 227   // Platform apps host permission changes do not count as privilege increases.
 228   // Note: this must remain consistent with AddHostPermissions.
 229   if (extension_type == Manifest::TYPE_PLATFORM_APP)
 230     return false;
 231
 232   // If the old permission set can access any host, then it can't be elevated.
 233   if (old_permissions->HasEffectiveAccessToAllHosts())
 234     return false;
 235
 236   // Likewise, if the new permission set has full host access, then it must be
 237   // a privilege increase.
 238   if (new_permissions->HasEffectiveAccessToAllHosts())
 239     return true;
 240
 241   const URLPatternSet& old_list = old_permissions->effective_hosts();
 242   const URLPatternSet& new_list = new_permissions->effective_hosts();
 243
 244   // TODO(jstritar): This is overly conservative with respect to subdomains.
 245   // For example, going from *.google.com to www.google.com will be
 246   // considered an elevation, even though it is not (http://crbug.com/65337).
 247   std::set<std::string> new_hosts_set(
 248       permission_message_util::GetDistinctHosts(new_list, false, false));
 249   std::set<std::string> old_hosts_set(
 250       permission_message_util::GetDistinctHosts(old_list, false, false));
 251   std::set<std::string> new_hosts_only =
 252       base::STLSetDifference<std::set<std::string> >(new_hosts_set,
 253                                                      old_hosts_set);
 254
 255   return !new_hosts_only.empty();
 256 }
 257
 258 }  // namespace extensions