chrome/browser/net/packed_ct_ev_whitelist.cc

   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
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/net/packed_ct_ev_whitelist.h"
   6
   7 #include <string.h>
   8
   9 #include <algorithm>
  10
  11 #include "base/big_endian.h"
  12 #include "base/files/file_util.h"
  13 #include "base/lazy_instance.h"
  14 #include "base/logging.h"
  15 #include "chrome/browser/net/bit_stream_reader.h"
  16 #include "content/public/browser/browser_thread.h"
  17 #include "net/ssl/ssl_config_service.h"
  18
  19 namespace {
  20 const uint8_t kCertHashLengthBits = 64;  // 8 bytes
  21 const uint8_t kCertHashLength = kCertHashLengthBits / 8;
  22 const uint64_t kGolombMParameterBits = 47;  // 2^47
  23
  24 void SetEVWhitelistInSSLConfigService(
  25     const scoped_refptr<net::ct::EVCertsWhitelist>& new_whitelist) {
  26   VLOG(1) << "Setting new EV Certs whitelist.";
  27   net::SSLConfigService::SetEVCertsWhitelist(new_whitelist);
  28 }
  29
  30 int TruncatedHashesComparator(const void* v1, const void* v2) {
  31   const uint64_t& h1(*(static_cast<const uint64_t*>(v1)));
  32   const uint64_t& h2(*(static_cast<const uint64_t*>(v2)));
  33   if (h1 < h2)
  34     return -1;
  35   else if (h1 > h2)
  36     return 1;
  37   return 0;
  38 }
  39 }  // namespace
  40
  41 void SetEVCertsWhitelist(scoped_refptr<net::ct::EVCertsWhitelist> whitelist) {
  42   if (!whitelist->IsValid()) {
  43     VLOG(1) << "EV Certs whitelist is not valid, not setting.";
  44     return;
  45   }
  46
  47   base::Closure assign_cb =
  48       base::Bind(SetEVWhitelistInSSLConfigService, whitelist);
  49   content::BrowserThread::PostTask(
  50       content::BrowserThread::IO, FROM_HERE, assign_cb);
  51 }
  52
  53 bool PackedEVCertsWhitelist::UncompressEVWhitelist(
  54     const std::string& compressed_whitelist,
  55     std::vector<uint64_t>* uncompressed_list) {
  56   internal::BitStreamReader reader(base::StringPiece(
  57       compressed_whitelist.data(), compressed_whitelist.size()));
  58   std::vector<uint64_t> result;
  59
  60   VLOG(1) << "Uncompressing EV whitelist of size "
  61           << compressed_whitelist.size();
  62   uint64_t curr_hash(0);
  63   if (!reader.ReadBits(kCertHashLengthBits, &curr_hash)) {
  64     VLOG(1) << "Failed reading first hash.";
  65     return false;
  66   }
  67   result.push_back(curr_hash);
  68   // M is the tunable parameter used by the Golomb coding.
  69   static const uint64_t kGolombParameterM = static_cast<uint64_t>(1)
  70                                             << kGolombMParameterBits;
  71
  72   while (reader.BitsLeft() > kGolombMParameterBits) {
  73     uint64_t read_prefix = 0;
  74     if (!reader.ReadUnaryEncoding(&read_prefix)) {
  75       VLOG(1) << "Failed reading unary-encoded prefix.";
  76       return false;
  77     }
  78     if (read_prefix > (UINT64_MAX / kGolombParameterM)) {
  79       VLOG(1) << "Received value that would cause overflow: " << read_prefix;
  80       return false;
  81     }
  82
  83     uint64_t r = 0;
  84     if (!reader.ReadBits(kGolombMParameterBits, &r)) {
  85       VLOG(1) << "Failed reading " << kGolombMParameterBits << " bits.";
  86       return false;
  87     }
  88     DCHECK_LT(r, kGolombParameterM);
  89
  90     uint64_t curr_diff = read_prefix * kGolombParameterM + r;
  91     curr_hash += curr_diff;
  92
  93     result.push_back(curr_hash);
  94   }
  95
  96   uncompressed_list->swap(result);
  97   return true;
  98 }
  99
 100 PackedEVCertsWhitelist::PackedEVCertsWhitelist(
 101     const std::string& compressed_whitelist) {
 102   if (!UncompressEVWhitelist(compressed_whitelist, &whitelist_)) {
 103     whitelist_.clear();
 104     return;
 105   }
 106 }
 107
 108 PackedEVCertsWhitelist::~PackedEVCertsWhitelist() {
 109 }
 110
 111 bool PackedEVCertsWhitelist::ContainsCertificateHash(
 112     const std::string& certificate_hash) const {
 113   DCHECK(!whitelist_.empty());
 114   uint64_t hash_to_lookup;
 115
 116   base::ReadBigEndian(certificate_hash.data(), &hash_to_lookup);
 117   return bsearch(&hash_to_lookup,
 118                  &whitelist_[0],
 119                  whitelist_.size(),
 120                  kCertHashLength,
 121                  TruncatedHashesComparator) != NULL;
 122 }
 123
 124 bool PackedEVCertsWhitelist::IsValid() const {
 125   return whitelist_.size() > 0;
 126 }