src/chrome/common/extensions/features/simple_feature.cc

   1 // Copyright (c) 2012 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/features/simple_feature.h"
   6
   7 #include <map>
   8 #include <vector>
   9
  10 #include "base/command_line.h"
  11 #include "base/lazy_instance.h"
  12 #include "base/sha1.h"
  13 #include "base/strings/string_number_conversions.h"
  14 #include "base/strings/string_util.h"
  15 #include "base/strings/stringprintf.h"
  16 #include "chrome/common/chrome_switches.h"
  17 #include "chrome/common/extensions/features/feature_channel.h"
  18
  19 using chrome::VersionInfo;
  20
  21 namespace extensions {
  22
  23 namespace {
  24
  25 struct Mappings {
  26   Mappings() {
  27     extension_types["extension"] = Manifest::TYPE_EXTENSION;
  28     extension_types["theme"] = Manifest::TYPE_THEME;
  29     extension_types["legacy_packaged_app"] = Manifest::TYPE_LEGACY_PACKAGED_APP;
  30     extension_types["hosted_app"] = Manifest::TYPE_HOSTED_APP;
  31     extension_types["platform_app"] = Manifest::TYPE_PLATFORM_APP;
  32     extension_types["shared_module"] = Manifest::TYPE_SHARED_MODULE;
  33
  34     contexts["blessed_extension"] = Feature::BLESSED_EXTENSION_CONTEXT;
  35     contexts["unblessed_extension"] = Feature::UNBLESSED_EXTENSION_CONTEXT;
  36     contexts["content_script"] = Feature::CONTENT_SCRIPT_CONTEXT;
  37     contexts["web_page"] = Feature::WEB_PAGE_CONTEXT;
  38
  39     locations["component"] = Feature::COMPONENT_LOCATION;
  40
  41     platforms["chromeos"] = Feature::CHROMEOS_PLATFORM;
  42     platforms["linux"] = Feature::LINUX_PLATFORM;
  43     platforms["macosx"] = Feature::MACOSX_PLATFORM;
  44     platforms["windows"] = Feature::WIN_PLATFORM;
  45
  46     channels["trunk"] = VersionInfo::CHANNEL_UNKNOWN;
  47     channels["canary"] = VersionInfo::CHANNEL_CANARY;
  48     channels["dev"] = VersionInfo::CHANNEL_DEV;
  49     channels["beta"] = VersionInfo::CHANNEL_BETA;
  50     channels["stable"] = VersionInfo::CHANNEL_STABLE;
  51   }
  52
  53   std::map<std::string, Manifest::Type> extension_types;
  54   std::map<std::string, Feature::Context> contexts;
  55   std::map<std::string, Feature::Location> locations;
  56   std::map<std::string, Feature::Platform> platforms;
  57   std::map<std::string, VersionInfo::Channel> channels;
  58 };
  59
  60 base::LazyInstance<Mappings> g_mappings = LAZY_INSTANCE_INITIALIZER;
  61
  62 std::string GetChannelName(VersionInfo::Channel channel) {
  63   typedef std::map<std::string, VersionInfo::Channel> ChannelsMap;
  64   ChannelsMap channels = g_mappings.Get().channels;
  65   for (ChannelsMap::iterator i = channels.begin(); i != channels.end(); ++i) {
  66     if (i->second == channel)
  67       return i->first;
  68   }
  69   NOTREACHED();
  70   return "unknown";
  71 }
  72
  73 // TODO(aa): Can we replace all this manual parsing with JSON schema stuff?
  74
  75 void ParseSet(const base::DictionaryValue* value,
  76               const std::string& property,
  77               std::set<std::string>* set) {
  78   const base::ListValue* list_value = NULL;
  79   if (!value->GetList(property, &list_value))
  80     return;
  81
  82   set->clear();
  83   for (size_t i = 0; i < list_value->GetSize(); ++i) {
  84     std::string str_val;
  85     CHECK(list_value->GetString(i, &str_val)) << property << " " << i;
  86     set->insert(str_val);
  87   }
  88 }
  89
  90 template<typename T>
  91 void ParseEnum(const std::string& string_value,
  92                T* enum_value,
  93                const std::map<std::string, T>& mapping) {
  94   typename std::map<std::string, T>::const_iterator iter =
  95       mapping.find(string_value);
  96   CHECK(iter != mapping.end()) << string_value;
  97   *enum_value = iter->second;
  98 }
  99
 100 template<typename T>
 101 void ParseEnum(const base::DictionaryValue* value,
 102                const std::string& property,
 103                T* enum_value,
 104                const std::map<std::string, T>& mapping) {
 105   std::string string_value;
 106   if (!value->GetString(property, &string_value))
 107     return;
 108
 109   ParseEnum(string_value, enum_value, mapping);
 110 }
 111
 112 template<typename T>
 113 void ParseEnumSet(const base::DictionaryValue* value,
 114                   const std::string& property,
 115                   std::set<T>* enum_set,
 116                   const std::map<std::string, T>& mapping) {
 117   if (!value->HasKey(property))
 118     return;
 119
 120   enum_set->clear();
 121
 122   std::string property_string;
 123   if (value->GetString(property, &property_string)) {
 124     if (property_string == "all") {
 125       for (typename std::map<std::string, T>::const_iterator j =
 126                mapping.begin(); j != mapping.end(); ++j) {
 127         enum_set->insert(j->second);
 128       }
 129     }
 130     return;
 131   }
 132
 133   std::set<std::string> string_set;
 134   ParseSet(value, property, &string_set);
 135   for (std::set<std::string>::iterator iter = string_set.begin();
 136        iter != string_set.end(); ++iter) {
 137     T enum_value = static_cast<T>(0);
 138     ParseEnum(*iter, &enum_value, mapping);
 139     enum_set->insert(enum_value);
 140   }
 141 }
 142
 143 void ParseURLPatterns(const base::DictionaryValue* value,
 144                       const std::string& key,
 145                       URLPatternSet* set) {
 146   const base::ListValue* matches = NULL;
 147   if (value->GetList(key, &matches)) {
 148     set->ClearPatterns();
 149     for (size_t i = 0; i < matches->GetSize(); ++i) {
 150       std::string pattern;
 151       CHECK(matches->GetString(i, &pattern));
 152       set->AddPattern(URLPattern(URLPattern::SCHEME_ALL, pattern));
 153     }
 154   }
 155 }
 156
 157 // Gets a human-readable name for the given extension type, suitable for giving
 158 // to developers in an error message.
 159 std::string GetDisplayName(Manifest::Type type) {
 160   switch (type) {
 161     case Manifest::TYPE_UNKNOWN:
 162       return "unknown";
 163     case Manifest::TYPE_EXTENSION:
 164       return "extension";
 165     case Manifest::TYPE_HOSTED_APP:
 166       return "hosted app";
 167     case Manifest::TYPE_LEGACY_PACKAGED_APP:
 168       return "legacy packaged app";
 169     case Manifest::TYPE_PLATFORM_APP:
 170       return "packaged app";
 171     case Manifest::TYPE_THEME:
 172       return "theme";
 173     case Manifest::TYPE_USER_SCRIPT:
 174       return "user script";
 175     case Manifest::TYPE_SHARED_MODULE:
 176       return "shared module";
 177   }
 178   NOTREACHED();
 179   return "";
 180 }
 181
 182 // Gets a human-readable name for the given context type, suitable for giving
 183 // to developers in an error message.
 184 std::string GetDisplayName(Feature::Context context) {
 185   switch (context) {
 186     case Feature::UNSPECIFIED_CONTEXT:
 187       return "unknown";
 188     case Feature::BLESSED_EXTENSION_CONTEXT:
 189       // "privileged" is vague but hopefully the developer will understand that
 190       // means background or app window.
 191       return "privileged page";
 192     case Feature::UNBLESSED_EXTENSION_CONTEXT:
 193       // "iframe" is a bit of a lie/oversimplification, but that's the most
 194       // common unblessed context.
 195       return "extension iframe";
 196     case Feature::CONTENT_SCRIPT_CONTEXT:
 197       return "content script";
 198     case Feature::WEB_PAGE_CONTEXT:
 199       return "web page";
 200   }
 201   NOTREACHED();
 202   return "";
 203 }
 204
 205 // Gets a human-readable list of the display names (pluralized, comma separated
 206 // with the "and" in the correct place) for each of |enum_types|.
 207 template <typename EnumType>
 208 std::string ListDisplayNames(const std::vector<EnumType> enum_types) {
 209   std::string display_name_list;
 210   for (size_t i = 0; i < enum_types.size(); ++i) {
 211     // Pluralize type name.
 212     display_name_list += GetDisplayName(enum_types[i]) + "s";
 213     // Comma-separate entries, with an Oxford comma if there is more than 2
 214     // total entries.
 215     if (enum_types.size() > 2) {
 216       if (i < enum_types.size() - 2)
 217         display_name_list += ", ";
 218       else if (i == enum_types.size() - 2)
 219         display_name_list += ", and ";
 220     } else if (enum_types.size() == 2 && i == 0) {
 221       display_name_list += " and ";
 222     }
 223   }
 224   return display_name_list;
 225 }
 226
 227 std::string HashExtensionId(const std::string& extension_id) {
 228   const std::string id_hash = base::SHA1HashString(extension_id);
 229   DCHECK(id_hash.length() == base::kSHA1Length);
 230   return base::HexEncode(id_hash.c_str(), id_hash.length());
 231 }
 232
 233 }  // namespace
 234
 235 SimpleFeature::SimpleFeature()
 236   : location_(UNSPECIFIED_LOCATION),
 237     min_manifest_version_(0),
 238     max_manifest_version_(0),
 239     channel_(VersionInfo::CHANNEL_UNKNOWN),
 240     has_parent_(false),
 241     channel_has_been_set_(false) {
 242 }
 243
 244 SimpleFeature::SimpleFeature(const SimpleFeature& other)
 245     : whitelist_(other.whitelist_),
 246       extension_types_(other.extension_types_),
 247       contexts_(other.contexts_),
 248       matches_(other.matches_),
 249       location_(other.location_),
 250       platforms_(other.platforms_),
 251       min_manifest_version_(other.min_manifest_version_),
 252       max_manifest_version_(other.max_manifest_version_),
 253       channel_(other.channel_),
 254       has_parent_(other.has_parent_),
 255       channel_has_been_set_(other.channel_has_been_set_) {
 256 }
 257
 258 SimpleFeature::~SimpleFeature() {
 259 }
 260
 261 bool SimpleFeature::Equals(const SimpleFeature& other) const {
 262   return whitelist_ == other.whitelist_ &&
 263       extension_types_ == other.extension_types_ &&
 264       contexts_ == other.contexts_ &&
 265       matches_ == other.matches_ &&
 266       location_ == other.location_ &&
 267       platforms_ == other.platforms_ &&
 268       min_manifest_version_ == other.min_manifest_version_ &&
 269       max_manifest_version_ == other.max_manifest_version_ &&
 270       channel_ == other.channel_ &&
 271       has_parent_ == other.has_parent_ &&
 272       channel_has_been_set_ == other.channel_has_been_set_;
 273 }
 274
 275 std::string SimpleFeature::Parse(const base::DictionaryValue* value) {
 276   ParseURLPatterns(value, "matches", &matches_);
 277   ParseSet(value, "whitelist", &whitelist_);
 278   ParseSet(value, "dependencies", &dependencies_);
 279   ParseEnumSet<Manifest::Type>(value, "extension_types", &extension_types_,
 280                                 g_mappings.Get().extension_types);
 281   ParseEnumSet<Context>(value, "contexts", &contexts_,
 282                         g_mappings.Get().contexts);
 283   ParseEnum<Location>(value, "location", &location_,
 284                       g_mappings.Get().locations);
 285   ParseEnumSet<Platform>(value, "platforms", &platforms_,
 286                          g_mappings.Get().platforms);
 287   value->GetInteger("min_manifest_version", &min_manifest_version_);
 288   value->GetInteger("max_manifest_version", &max_manifest_version_);
 289   ParseEnum<VersionInfo::Channel>(
 290       value, "channel", &channel_,
 291       g_mappings.Get().channels);
 292
 293   no_parent_ = false;
 294   value->GetBoolean("noparent", &no_parent_);
 295
 296   // The "trunk" channel uses VersionInfo::CHANNEL_UNKNOWN, so we need to keep
 297   // track of whether the channel has been set or not separately.
 298   channel_has_been_set_ |= value->HasKey("channel");
 299   if (!channel_has_been_set_ && dependencies_.empty())
 300     return name() + ": Must supply a value for channel or dependencies.";
 301
 302   if (matches_.is_empty() && contexts_.count(WEB_PAGE_CONTEXT) != 0) {
 303     return name() + ": Allowing web_page contexts requires supplying a value " +
 304         "for matches.";
 305   }
 306
 307   return std::string();
 308 }
 309
 310 Feature::Availability SimpleFeature::IsAvailableToManifest(
 311     const std::string& extension_id,
 312     Manifest::Type type,
 313     Location location,
 314     int manifest_version,
 315     Platform platform) const {
 316   // Component extensions can access any feature.
 317   if (location == COMPONENT_LOCATION)
 318     return CreateAvailability(IS_AVAILABLE, type);
 319
 320   if (!whitelist_.empty()) {
 321     if (!IsIdInWhitelist(extension_id)) {
 322       // TODO(aa): This is gross. There should be a better way to test the
 323       // whitelist.
 324       CommandLine* command_line = CommandLine::ForCurrentProcess();
 325       if (!command_line->HasSwitch(switches::kWhitelistedExtensionID))
 326         return CreateAvailability(NOT_FOUND_IN_WHITELIST, type);
 327
 328       std::string whitelist_switch_value =
 329           CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
 330               switches::kWhitelistedExtensionID);
 331       if (extension_id != whitelist_switch_value)
 332         return CreateAvailability(NOT_FOUND_IN_WHITELIST, type);
 333     }
 334   }
 335
 336   // HACK(kalman): user script -> extension. Solve this in a more generic way
 337   // when we compile feature files.
 338   Manifest::Type type_to_check = (type == Manifest::TYPE_USER_SCRIPT) ?
 339       Manifest::TYPE_EXTENSION : type;
 340   if (!extension_types_.empty() &&
 341       extension_types_.find(type_to_check) == extension_types_.end()) {
 342     return CreateAvailability(INVALID_TYPE, type);
 343   }
 344
 345   if (location_ != UNSPECIFIED_LOCATION && location_ != location)
 346     return CreateAvailability(INVALID_LOCATION, type);
 347
 348   if (!platforms_.empty() &&
 349       platforms_.find(platform) == platforms_.end())
 350     return CreateAvailability(INVALID_PLATFORM, type);
 351
 352   if (min_manifest_version_ != 0 && manifest_version < min_manifest_version_)
 353     return CreateAvailability(INVALID_MIN_MANIFEST_VERSION, type);
 354
 355   if (max_manifest_version_ != 0 && manifest_version > max_manifest_version_)
 356     return CreateAvailability(INVALID_MAX_MANIFEST_VERSION, type);
 357
 358   if (channel_has_been_set_ && channel_ < GetCurrentChannel())
 359     return CreateAvailability(UNSUPPORTED_CHANNEL, type);
 360
 361   return CreateAvailability(IS_AVAILABLE, type);
 362 }
 363
 364 Feature::Availability SimpleFeature::IsAvailableToContext(
 365     const Extension* extension,
 366     SimpleFeature::Context context,
 367     const GURL& url,
 368     SimpleFeature::Platform platform) const {
 369   if (extension) {
 370     Availability result = IsAvailableToManifest(
 371         extension->id(),
 372         extension->GetType(),
 373         ConvertLocation(extension->location()),
 374         extension->manifest_version(),
 375         platform);
 376     if (!result.is_available())
 377       return result;
 378   }
 379
 380   if (!contexts_.empty() && contexts_.find(context) == contexts_.end())
 381     return CreateAvailability(INVALID_CONTEXT, context);
 382
 383   if (!matches_.is_empty() && !matches_.MatchesURL(url))
 384     return CreateAvailability(INVALID_URL, url);
 385
 386   return CreateAvailability(IS_AVAILABLE);
 387 }
 388
 389 std::string SimpleFeature::GetAvailabilityMessage(
 390     AvailabilityResult result,
 391     Manifest::Type type,
 392     const GURL& url,
 393     Context context) const {
 394   switch (result) {
 395     case IS_AVAILABLE:
 396       return std::string();
 397     case NOT_FOUND_IN_WHITELIST:
 398       return base::StringPrintf(
 399           "'%s' is not allowed for specified extension ID.",
 400           name().c_str());
 401     case INVALID_URL:
 402       return base::StringPrintf("'%s' is not allowed on %s.",
 403                                 name().c_str(), url.spec().c_str());
 404     case INVALID_TYPE:
 405       return base::StringPrintf(
 406           "'%s' is only allowed for %s, but this is a %s.",
 407           name().c_str(),
 408           ListDisplayNames(std::vector<Manifest::Type>(
 409               extension_types_.begin(), extension_types_.end())).c_str(),
 410           GetDisplayName(type).c_str());
 411     case INVALID_CONTEXT:
 412       return base::StringPrintf(
 413           "'%s' is only allowed to run in %s, but this is a %s",
 414           name().c_str(),
 415           ListDisplayNames(std::vector<Context>(
 416               contexts_.begin(), contexts_.end())).c_str(),
 417           GetDisplayName(context).c_str());
 418     case INVALID_LOCATION:
 419       return base::StringPrintf(
 420           "'%s' is not allowed for specified install location.",
 421           name().c_str());
 422     case INVALID_PLATFORM:
 423       return base::StringPrintf(
 424           "'%s' is not allowed for specified platform.",
 425           name().c_str());
 426     case INVALID_MIN_MANIFEST_VERSION:
 427       return base::StringPrintf(
 428           "'%s' requires manifest version of at least %d.",
 429           name().c_str(),
 430           min_manifest_version_);
 431     case INVALID_MAX_MANIFEST_VERSION:
 432       return base::StringPrintf(
 433           "'%s' requires manifest version of %d or lower.",
 434           name().c_str(),
 435           max_manifest_version_);
 436     case NOT_PRESENT:
 437       return base::StringPrintf(
 438           "'%s' requires a different Feature that is not present.",
 439           name().c_str());
 440     case UNSUPPORTED_CHANNEL:
 441       return base::StringPrintf(
 442           "'%s' requires Google Chrome %s channel or newer, but this is the "
 443               "%s channel.",
 444           name().c_str(),
 445           GetChannelName(channel_).c_str(),
 446           GetChannelName(GetCurrentChannel()).c_str());
 447   }
 448
 449   NOTREACHED();
 450   return std::string();
 451 }
 452
 453 Feature::Availability SimpleFeature::CreateAvailability(
 454     AvailabilityResult result) const {
 455   return Availability(
 456       result, GetAvailabilityMessage(result, Manifest::TYPE_UNKNOWN, GURL(),
 457                                      UNSPECIFIED_CONTEXT));
 458 }
 459
 460 Feature::Availability SimpleFeature::CreateAvailability(
 461     AvailabilityResult result, Manifest::Type type) const {
 462   return Availability(result, GetAvailabilityMessage(result, type, GURL(),
 463                                                      UNSPECIFIED_CONTEXT));
 464 }
 465
 466 Feature::Availability SimpleFeature::CreateAvailability(
 467     AvailabilityResult result,
 468     const GURL& url) const {
 469   return Availability(
 470       result, GetAvailabilityMessage(result, Manifest::TYPE_UNKNOWN, url,
 471                                      UNSPECIFIED_CONTEXT));
 472 }
 473
 474 Feature::Availability SimpleFeature::CreateAvailability(
 475     AvailabilityResult result,
 476     Context context) const {
 477   return Availability(
 478       result, GetAvailabilityMessage(result, Manifest::TYPE_UNKNOWN, GURL(),
 479                                      context));
 480 }
 481
 482 std::set<Feature::Context>* SimpleFeature::GetContexts() {
 483   return &contexts_;
 484 }
 485
 486 bool SimpleFeature::IsInternal() const {
 487   NOTREACHED();
 488   return false;
 489 }
 490
 491 bool SimpleFeature::IsIdInWhitelist(const std::string& extension_id) const {
 492   return IsIdInWhitelist(extension_id, whitelist_);
 493 }
 494
 495 // static
 496 bool SimpleFeature::IsIdInWhitelist(const std::string& extension_id,
 497                                     const std::set<std::string>& whitelist) {
 498   // Belt-and-suspenders philosophy here. We should be pretty confident by this
 499   // point that we've validated the extension ID format, but in case something
 500   // slips through, we avoid a class of attack where creative ID manipulation
 501   // leads to hash collisions.
 502   if (extension_id.length() != 32)  // 128 bits / 4 = 32 mpdecimal characters
 503     return false;
 504
 505   if (whitelist.find(extension_id) != whitelist.end() ||
 506       whitelist.find(HashExtensionId(extension_id)) != whitelist.end()) {
 507     return true;
 508   }
 509
 510   return false;
 511 }
 512
 513 }  // namespace extensions