chrome/browser/safe_browsing/safe_browsing_util.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/browser/safe_browsing/safe_browsing_util.h"
   6
   7 #include "base/logging.h"
   8 #include "base/strings/string_util.h"
   9 #include "base/strings/stringprintf.h"
  10 #include "chrome/browser/browser_process.h"
  11 #include "chrome/browser/safe_browsing/chunk.pb.h"
  12 #include "components/google/core/browser/google_util.h"
  13 #include "crypto/sha2.h"
  14 #include "net/base/escape.h"
  15 #include "url/gurl.h"
  16 #include "url/url_util.h"
  17
  18 #if defined(OS_WIN)
  19 #include "chrome/installer/util/browser_distribution.h"
  20 #endif
  21
  22 static const char kReportParams[] = "?tpl=%s&url=%s";
  23
  24 SBFullHash SBFullHashForString(const base::StringPiece& str) {
  25   SBFullHash h;
  26   crypto::SHA256HashString(str, &h.full_hash, sizeof(h.full_hash));
  27   return h;
  28 }
  29
  30 // SBCachedFullHashResult ------------------------------------------------------
  31
  32 SBCachedFullHashResult::SBCachedFullHashResult() {}
  33
  34 SBCachedFullHashResult::SBCachedFullHashResult(
  35     const base::Time& in_expire_after)
  36     : expire_after(in_expire_after) {}
  37
  38 SBCachedFullHashResult::~SBCachedFullHashResult() {}
  39
  40 // SBChunkData -----------------------------------------------------------------
  41
  42 // TODO(shess): Right now this contains a scoped_ptr<ChunkData> so that the
  43 // proto buffer isn't copied all over the place, then these are contained in a
  44 // ScopedVector for purposes of passing things around between tasks.  This seems
  45 // convoluted.  Maybe it would make sense to have an overall container class
  46 // returning references to a nested per-chunk class?
  47
  48 SBChunkData::SBChunkData() {
  49 }
  50
  51 SBChunkData::SBChunkData(safe_browsing::ChunkData* raw_data)
  52     : chunk_data_(raw_data) {
  53   DCHECK(chunk_data_.get());
  54 }
  55
  56 SBChunkData::~SBChunkData() {
  57 }
  58
  59 bool SBChunkData::ParseFrom(const unsigned char* data, size_t length) {
  60   scoped_ptr<safe_browsing::ChunkData> chunk(new safe_browsing::ChunkData());
  61   if (!chunk->ParseFromArray(data, length))
  62     return false;
  63
  64   if (chunk->chunk_type() != safe_browsing::ChunkData::ADD &&
  65       chunk->chunk_type() != safe_browsing::ChunkData::SUB) {
  66     return false;
  67   }
  68
  69   size_t hash_size = 0;
  70   if (chunk->prefix_type() == safe_browsing::ChunkData::PREFIX_4B) {
  71     hash_size = sizeof(SBPrefix);
  72   } else if (chunk->prefix_type() == safe_browsing::ChunkData::FULL_32B) {
  73     hash_size = sizeof(SBFullHash);
  74   } else {
  75     return false;
  76   }
  77
  78   const size_t hash_count = chunk->hashes().size() / hash_size;
  79   if (hash_count * hash_size != chunk->hashes().size())
  80     return false;
  81
  82   if (chunk->chunk_type() == safe_browsing::ChunkData::SUB &&
  83       static_cast<size_t>(chunk->add_numbers_size()) != hash_count) {
  84     return false;
  85   }
  86
  87   chunk_data_.swap(chunk);
  88   return true;
  89 }
  90
  91 int SBChunkData::ChunkNumber() const {
  92   return chunk_data_->chunk_number();
  93 }
  94
  95 bool SBChunkData::IsAdd() const {
  96   return chunk_data_->chunk_type() == safe_browsing::ChunkData::ADD;
  97 }
  98
  99 bool SBChunkData::IsSub() const {
 100   return chunk_data_->chunk_type() == safe_browsing::ChunkData::SUB;
 101 }
 102
 103 int SBChunkData::AddChunkNumberAt(size_t i) const {
 104   DCHECK(IsSub());
 105   DCHECK((IsPrefix() && i < PrefixCount()) ||
 106          (IsFullHash() && i < FullHashCount()));
 107   return chunk_data_->add_numbers(i);
 108 }
 109
 110 bool SBChunkData::IsPrefix() const {
 111   return chunk_data_->prefix_type() == safe_browsing::ChunkData::PREFIX_4B;
 112 }
 113
 114 size_t SBChunkData::PrefixCount() const {
 115   DCHECK(IsPrefix());
 116   return chunk_data_->hashes().size() / sizeof(SBPrefix);
 117 }
 118
 119 SBPrefix SBChunkData::PrefixAt(size_t i) const {
 120   DCHECK(IsPrefix());
 121   DCHECK_LT(i, PrefixCount());
 122
 123   SBPrefix prefix;
 124   memcpy(&prefix, chunk_data_->hashes().data() + i * sizeof(SBPrefix),
 125          sizeof(SBPrefix));
 126   return prefix;
 127 }
 128
 129 bool SBChunkData::IsFullHash() const {
 130   return chunk_data_->prefix_type() == safe_browsing::ChunkData::FULL_32B;
 131 }
 132
 133 size_t SBChunkData::FullHashCount() const {
 134   DCHECK(IsFullHash());
 135   return chunk_data_->hashes().size() / sizeof(SBFullHash);
 136 }
 137
 138 SBFullHash SBChunkData::FullHashAt(size_t i) const {
 139   DCHECK(IsFullHash());
 140   DCHECK_LT(i, FullHashCount());
 141
 142   SBFullHash full_hash;
 143   memcpy(&full_hash, chunk_data_->hashes().data() + i * sizeof(SBFullHash),
 144          sizeof(SBFullHash));
 145   return full_hash;
 146 }
 147
 148 // SBListChunkRanges -----------------------------------------------------------
 149
 150 SBListChunkRanges::SBListChunkRanges(const std::string& n)
 151     : name(n) {
 152 }
 153
 154 // SBChunkDelete ---------------------------------------------------------------
 155
 156 SBChunkDelete::SBChunkDelete() : is_sub_del(false) {}
 157
 158 SBChunkDelete::~SBChunkDelete() {}
 159
 160 // Utility functions -----------------------------------------------------------
 161
 162 namespace {
 163 bool IsKnownList(const std::string& name) {
 164   for (size_t i = 0; i < arraysize(safe_browsing_util::kAllLists); ++i) {
 165     if (!strcmp(safe_browsing_util::kAllLists[i], name.c_str())) {
 166       return true;
 167     }
 168   }
 169   return false;
 170 }
 171 }  // namespace
 172
 173 namespace safe_browsing_util {
 174
 175 // Listnames that browser can process.
 176 // TODO(shess): This shouldn't be OS-driven <http://crbug.com/394379>
 177 #if defined(OS_ANDROID)
 178 // NOTE(shess): This difference is also reflected in the store name in
 179 // safe_browsing_database.cc.
 180 const char kMalwareList[] = "goog-mobilemalware-shavar";
 181 const char kPhishingList[] = "goog-mobilephish-shavar";
 182 #else
 183 const char kMalwareList[] = "goog-malware-shavar";
 184 const char kPhishingList[] = "goog-phish-shavar";
 185 #endif
 186 const char kBinUrlList[] = "goog-badbinurl-shavar";
 187 const char kCsdWhiteList[] = "goog-csdwhite-sha256";
 188 const char kDownloadWhiteList[] = "goog-downloadwhite-digest256";
 189 const char kExtensionBlacklist[] = "goog-badcrxids-digestvar";
 190 const char kSideEffectFreeWhitelist[] = "goog-sideeffectfree-shavar";
 191 const char kIPBlacklist[] = "goog-badip-digest256";
 192
 193 const char* kAllLists[8] = {
 194   kMalwareList,
 195   kPhishingList,
 196   kBinUrlList,
 197   kCsdWhiteList,
 198   kDownloadWhiteList,
 199   kExtensionBlacklist,
 200   kSideEffectFreeWhitelist,
 201   kIPBlacklist,
 202 };
 203
 204 ListType GetListId(const base::StringPiece& name) {
 205   ListType id;
 206   if (name == safe_browsing_util::kMalwareList) {
 207     id = MALWARE;
 208   } else if (name == safe_browsing_util::kPhishingList) {
 209     id = PHISH;
 210   } else if (name == safe_browsing_util::kBinUrlList) {
 211     id = BINURL;
 212   } else if (name == safe_browsing_util::kCsdWhiteList) {
 213     id = CSDWHITELIST;
 214   } else if (name == safe_browsing_util::kDownloadWhiteList) {
 215     id = DOWNLOADWHITELIST;
 216   } else if (name == safe_browsing_util::kExtensionBlacklist) {
 217     id = EXTENSIONBLACKLIST;
 218   } else if (name == safe_browsing_util::kSideEffectFreeWhitelist) {
 219     id = SIDEEFFECTFREEWHITELIST;
 220   } else if (name == safe_browsing_util::kIPBlacklist) {
 221     id = IPBLACKLIST;
 222   } else {
 223     id = INVALID;
 224   }
 225   return id;
 226 }
 227
 228 bool GetListName(ListType list_id, std::string* list) {
 229   switch (list_id) {
 230     case MALWARE:
 231       *list = safe_browsing_util::kMalwareList;
 232       break;
 233     case PHISH:
 234       *list = safe_browsing_util::kPhishingList;
 235       break;
 236     case BINURL:
 237       *list = safe_browsing_util::kBinUrlList;
 238       break;
 239     case CSDWHITELIST:
 240       *list = safe_browsing_util::kCsdWhiteList;
 241       break;
 242     case DOWNLOADWHITELIST:
 243       *list = safe_browsing_util::kDownloadWhiteList;
 244       break;
 245     case EXTENSIONBLACKLIST:
 246       *list = safe_browsing_util::kExtensionBlacklist;
 247       break;
 248     case SIDEEFFECTFREEWHITELIST:
 249       *list = safe_browsing_util::kSideEffectFreeWhitelist;
 250       break;
 251     case IPBLACKLIST:
 252       *list = safe_browsing_util::kIPBlacklist;
 253       break;
 254     default:
 255       return false;
 256   }
 257   DCHECK(IsKnownList(*list));
 258   return true;
 259 }
 260
 261 std::string Unescape(const std::string& url) {
 262   std::string unescaped_str(url);
 263   std::string old_unescaped_str;
 264   const int kMaxLoopIterations = 1024;
 265   int loop_var = 0;
 266   do {
 267     old_unescaped_str = unescaped_str;
 268     unescaped_str = net::UnescapeURLComponent(old_unescaped_str,
 269         net::UnescapeRule::CONTROL_CHARS | net::UnescapeRule::SPACES |
 270         net::UnescapeRule::URL_SPECIAL_CHARS);
 271   } while (unescaped_str != old_unescaped_str && ++loop_var <=
 272            kMaxLoopIterations);
 273
 274   return unescaped_str;
 275 }
 276
 277 std::string Escape(const std::string& url) {
 278   std::string escaped_str;
 279   const char* kHexString = "0123456789ABCDEF";
 280   for (size_t i = 0; i < url.length(); i++) {
 281     unsigned char c = static_cast<unsigned char>(url[i]);
 282     if (c <= ' ' || c > '~' || c == '#' || c == '%') {
 283       escaped_str.push_back('%');
 284       escaped_str.push_back(kHexString[c >> 4]);
 285       escaped_str.push_back(kHexString[c & 0xf]);
 286     } else {
 287       escaped_str.push_back(c);
 288     }
 289   }
 290
 291   return escaped_str;
 292 }
 293
 294 std::string RemoveConsecutiveChars(const std::string& str, const char c) {
 295   std::string output(str);
 296   std::string string_to_find;
 297   std::string::size_type loc = 0;
 298   string_to_find.append(2, c);
 299   while ((loc = output.find(string_to_find, loc)) != std::string::npos) {
 300     output.erase(loc, 1);
 301   }
 302
 303   return output;
 304 }
 305
 306 // Canonicalizes url as per Google Safe Browsing Specification.
 307 // See section 6.1 in
 308 // http://code.google.com/p/google-safe-browsing/wiki/Protocolv2Spec.
 309 void CanonicalizeUrl(const GURL& url,
 310                      std::string* canonicalized_hostname,
 311                      std::string* canonicalized_path,
 312                      std::string* canonicalized_query) {
 313   DCHECK(url.is_valid());
 314
 315   // We only canonicalize "normal" URLs.
 316   if (!url.IsStandard())
 317     return;
 318
 319   // Following canonicalization steps are excluded since url parsing takes care
 320   // of those :-
 321   // 1. Remove any tab (0x09), CR (0x0d), and LF (0x0a) chars from url.
 322   //    (Exclude escaped version of these chars).
 323   // 2. Normalize hostname to 4 dot-seperated decimal values.
 324   // 3. Lowercase hostname.
 325   // 4. Resolve path sequences "/../" and "/./".
 326
 327   // That leaves us with the following :-
 328   // 1. Remove fragment in URL.
 329   GURL url_without_fragment;
 330   GURL::Replacements f_replacements;
 331   f_replacements.ClearRef();
 332   f_replacements.ClearUsername();
 333   f_replacements.ClearPassword();
 334   url_without_fragment = url.ReplaceComponents(f_replacements);
 335
 336   // 2. Do URL unescaping until no more hex encoded characters exist.
 337   std::string url_unescaped_str(Unescape(url_without_fragment.spec()));
 338   url::Parsed parsed;
 339   url::ParseStandardURL(url_unescaped_str.data(), url_unescaped_str.length(),
 340                         &parsed);
 341
 342   // 3. In hostname, remove all leading and trailing dots.
 343   const std::string host =
 344       (parsed.host.len > 0)
 345           ? url_unescaped_str.substr(parsed.host.begin, parsed.host.len)
 346           : std::string();
 347   std::string host_without_end_dots;
 348   base::TrimString(host, ".", &host_without_end_dots);
 349
 350   // 4. In hostname, replace consecutive dots with a single dot.
 351   std::string host_without_consecutive_dots(RemoveConsecutiveChars(
 352       host_without_end_dots, '.'));
 353
 354   // 5. In path, replace runs of consecutive slashes with a single slash.
 355   std::string path =
 356       (parsed.path.len > 0)
 357           ? url_unescaped_str.substr(parsed.path.begin, parsed.path.len)
 358           : std::string();
 359   std::string path_without_consecutive_slash(RemoveConsecutiveChars(path, '/'));
 360
 361   url::Replacements<char> hp_replacements;
 362   hp_replacements.SetHost(
 363       host_without_consecutive_dots.data(),
 364       url::Component(0, host_without_consecutive_dots.length()));
 365   hp_replacements.SetPath(
 366       path_without_consecutive_slash.data(),
 367       url::Component(0, path_without_consecutive_slash.length()));
 368
 369   std::string url_unescaped_with_can_hostpath;
 370   url::StdStringCanonOutput output(&url_unescaped_with_can_hostpath);
 371   url::Parsed temp_parsed;
 372   url::ReplaceComponents(url_unescaped_str.data(),
 373                          url_unescaped_str.length(),
 374                          parsed,
 375                          hp_replacements,
 376                          NULL,
 377                          &output,
 378                          &temp_parsed);
 379   output.Complete();
 380
 381   // 6. Step needed to revert escaping done in url::ReplaceComponents.
 382   url_unescaped_with_can_hostpath = Unescape(url_unescaped_with_can_hostpath);
 383
 384   // 7. After performing all above steps, percent-escape all chars in url which
 385   // are <= ASCII 32, >= 127, #, %. Escapes must be uppercase hex characters.
 386   std::string escaped_canon_url_str(Escape(url_unescaped_with_can_hostpath));
 387   url::Parsed final_parsed;
 388   url::ParseStandardURL(escaped_canon_url_str.data(),
 389                         escaped_canon_url_str.length(),
 390                         &final_parsed);
 391
 392   if (canonicalized_hostname && final_parsed.host.len > 0) {
 393     *canonicalized_hostname =
 394         escaped_canon_url_str.substr(final_parsed.host.begin,
 395                                      final_parsed.host.len);
 396   }
 397   if (canonicalized_path && final_parsed.path.len > 0) {
 398     *canonicalized_path = escaped_canon_url_str.substr(final_parsed.path.begin,
 399                                                        final_parsed.path.len);
 400   }
 401   if (canonicalized_query && final_parsed.query.len > 0) {
 402     *canonicalized_query = escaped_canon_url_str.substr(
 403         final_parsed.query.begin, final_parsed.query.len);
 404   }
 405 }
 406
 407 void GenerateHostsToCheck(const GURL& url, std::vector<std::string>* hosts) {
 408   hosts->clear();
 409
 410   std::string canon_host;
 411   CanonicalizeUrl(url, &canon_host, NULL, NULL);
 412
 413   const std::string host = canon_host;  // const sidesteps GCC bugs below!
 414   if (host.empty())
 415     return;
 416
 417   // Per the Safe Browsing Protocol v2 spec, we try the host, and also up to 4
 418   // hostnames formed by starting with the last 5 components and successively
 419   // removing the leading component.  The last component isn't examined alone,
 420   // since it's the TLD or a subcomponent thereof.
 421   //
 422   // Note that we don't need to be clever about stopping at the "real" eTLD --
 423   // the data on the server side has been filtered to ensure it will not
 424   // blacklist a whole TLD, and it's not significantly slower on our side to
 425   // just check too much.
 426   //
 427   // Also note that because we have a simple blacklist, not some sort of complex
 428   // whitelist-in-blacklist or vice versa, it doesn't matter what order we check
 429   // these in.
 430   const size_t kMaxHostsToCheck = 4;
 431   bool skipped_last_component = false;
 432   for (std::string::const_reverse_iterator i(host.rbegin());
 433        i != host.rend() && hosts->size() < kMaxHostsToCheck; ++i) {
 434     if (*i == '.') {
 435       if (skipped_last_component)
 436         hosts->push_back(std::string(i.base(), host.end()));
 437       else
 438         skipped_last_component = true;
 439     }
 440   }
 441   hosts->push_back(host);
 442 }
 443
 444 void GeneratePathsToCheck(const GURL& url, std::vector<std::string>* paths) {
 445   paths->clear();
 446
 447   std::string canon_path;
 448   std::string canon_query;
 449   CanonicalizeUrl(url, NULL, &canon_path, &canon_query);
 450
 451   const std::string path = canon_path;   // const sidesteps GCC bugs below!
 452   const std::string query = canon_query;
 453   if (path.empty())
 454     return;
 455
 456   // Per the Safe Browsing Protocol v2 spec, we try the exact path with/without
 457   // the query parameters, and also up to 4 paths formed by starting at the root
 458   // and adding more path components.
 459   //
 460   // As with the hosts above, it doesn't matter what order we check these in.
 461   const size_t kMaxPathsToCheck = 4;
 462   for (std::string::const_iterator i(path.begin());
 463        i != path.end() && paths->size() < kMaxPathsToCheck; ++i) {
 464     if (*i == '/')
 465       paths->push_back(std::string(path.begin(), i + 1));
 466   }
 467
 468   if (!paths->empty() && paths->back() != path)
 469     paths->push_back(path);
 470
 471   if (!query.empty())
 472     paths->push_back(path + "?" + query);
 473 }
 474
 475 void GeneratePatternsToCheck(const GURL& url, std::vector<std::string>* urls) {
 476   std::vector<std::string> hosts, paths;
 477   GenerateHostsToCheck(url, &hosts);
 478   GeneratePathsToCheck(url, &paths);
 479   for (size_t h = 0; h < hosts.size(); ++h) {
 480     for (size_t p = 0; p < paths.size(); ++p) {
 481       urls->push_back(hosts[h] + paths[p]);
 482     }
 483   }
 484 }
 485
 486 GURL GeneratePhishingReportUrl(const std::string& report_page,
 487                                const std::string& url_to_report,
 488                                bool is_client_side_detection) {
 489   const std::string current_esc = net::EscapeQueryParamValue(url_to_report,
 490                                                              true);
 491
 492 #if defined(OS_WIN)
 493   BrowserDistribution* dist = BrowserDistribution::GetDistribution();
 494   std::string client_name(dist->GetSafeBrowsingName());
 495 #else
 496   std::string client_name("googlechrome");
 497 #endif
 498   if (is_client_side_detection)
 499     client_name.append("_csd");
 500
 501   GURL report_url(report_page + base::StringPrintf(kReportParams,
 502                                                    client_name.c_str(),
 503                                                    current_esc.c_str()));
 504   return google_util::AppendGoogleLocaleParam(
 505       report_url, g_browser_process->GetApplicationLocale());
 506 }
 507
 508 SBFullHash StringToSBFullHash(const std::string& hash_in) {
 509   DCHECK_EQ(crypto::kSHA256Length, hash_in.size());
 510   SBFullHash hash_out;
 511   memcpy(hash_out.full_hash, hash_in.data(), crypto::kSHA256Length);
 512   return hash_out;
 513 }
 514
 515 std::string SBFullHashToString(const SBFullHash& hash) {
 516   DCHECK_EQ(crypto::kSHA256Length, sizeof(hash.full_hash));
 517   return std::string(hash.full_hash, sizeof(hash.full_hash));
 518 }
 519
 520 }  // namespace safe_browsing_util