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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 "net/cert/ct_ev_whitelist.h" | |
6 | |
7 #include <set> | |
8 | |
9 #include "base/big_endian.h" | |
10 #include "base/file_util.h" | |
11 #include "base/lazy_instance.h" | |
12 #include "base/logging.h" | |
13 | |
14 namespace net { | |
15 | |
16 namespace ct { | |
17 | |
18 namespace { | |
19 base::LazyInstance<std::set<std::string> >::Leaky g_current_ev_whitelist = | |
20 LAZY_INSTANCE_INITIALIZER; | |
21 | |
22 uint8 kCertHashLengthBits = 64; // 8 bytes | |
23 uint64 kGolombMParameterBits = 47; // 2^47 | |
wtc
2014/08/14 02:04:43
Add 'const' to these two constants.
Eran Messeri
2014/08/14 11:55:07
Done.
| |
24 | |
25 } | |
wtc
2014/08/14 02:04:43
Add a comment:
} // namespace
Eran Messeri
2014/08/14 11:55:07
Done.
| |
26 | |
27 namespace internal { | |
28 | |
29 BitStreamReader::BitStreamReader(const char* source, size_t length) : | |
30 source_(source), length_(length), curr_byte_(0), curr_bit_(7) { | |
31 } | |
32 | |
33 bool BitStreamReader::ReadUnaryEncoding(uint64* out) { | |
34 uint64 res(0); | |
35 if (!HasMoreBits()) { | |
36 return false; | |
37 } | |
38 | |
39 uint8 b = ReadBit(); | |
40 while (HasMoreBits() && b) { | |
41 res += 1; | |
42 b = ReadBit(); | |
43 } | |
44 | |
45 *out = res; | |
46 return true; | |
47 } | |
48 | |
49 bool BitStreamReader::ReadBits(uint8 num_bits, uint64* out) { | |
50 if (num_bits > 64) | |
51 return false; | |
52 | |
53 if (BitsLeft() < num_bits) | |
54 return false; | |
55 | |
56 uint64 res(0); | |
57 for (uint8 i = 0; i < num_bits; ++i) { | |
58 res |= (static_cast<uint64>(ReadBit()) << (num_bits - (i + 1))); | |
59 } | |
60 | |
61 *out = res; | |
62 return true; | |
63 } | |
64 | |
65 uint64 BitStreamReader::BitsLeft() { | |
66 if (curr_byte_ == length_) | |
67 return 0; | |
68 return (length_ - (curr_byte_ + 1)) * 8 + curr_bit_ + 1; | |
69 } | |
70 | |
71 bool BitStreamReader::HasMoreBits() { | |
72 return BitsLeft() > 0; | |
73 } | |
74 | |
75 uint8 BitStreamReader::ReadBit() { | |
76 DCHECK(HasMoreBits()); | |
77 DCHECK(curr_bit_ < 8 && curr_bit_ >= 0); | |
78 uint8 res = (source_[curr_byte_] & (1 << curr_bit_)) >> curr_bit_; | |
79 curr_bit_--; | |
80 if (curr_bit_ < 0) { | |
81 curr_byte_ += 1; | |
82 curr_bit_ = 7; | |
83 } | |
84 | |
85 return res; | |
86 } | |
87 | |
88 void SetEVWhitelistData(std::set<std::string> ev_whitelist) { | |
89 g_current_ev_whitelist.Get().swap(ev_whitelist); | |
90 } | |
91 | |
92 bool UncompressEVWhitelist( | |
93 const std::string& compressed_whitelist, | |
94 std::set<std::string>* uncompressed_list) { | |
95 BitStreamReader reader( | |
96 compressed_whitelist.data(), compressed_whitelist.size()); | |
97 std::set<std::string> result; | |
98 | |
99 VLOG(1) << "Uncompressing EV whitelist of size " | |
100 << compressed_whitelist.size(); | |
101 uint64 curr_hash(0); | |
102 if (!reader.ReadBits(kCertHashLengthBits, &curr_hash)) { | |
103 VLOG(1) << "Failed reading first hash."; | |
104 return false; | |
105 } | |
106 char hash_bytes[8]; | |
107 base::WriteBigEndian(hash_bytes, curr_hash); | |
108 result.insert(std::string(hash_bytes, 8)); | |
109 uint64 M = static_cast<uint64>(1) << kGolombMParameterBits; | |
110 | |
111 while (reader.BitsLeft() > kGolombMParameterBits) { | |
112 uint64 read_prefix(0); | |
113 if (!reader.ReadUnaryEncoding(&read_prefix)) { | |
114 VLOG(1) << "Failed reading unary-encoded prefix."; | |
115 return false; | |
116 } | |
117 | |
118 uint64 r(0); | |
119 if (!reader.ReadBits(kGolombMParameterBits, &r)) { | |
120 VLOG(1) << "Failed reading " << kGolombMParameterBits << " bits."; | |
121 return false; | |
122 } | |
123 | |
124 uint64 curr_diff = read_prefix * M + r; | |
125 uint64 next_hash = curr_hash + curr_diff; | |
126 | |
127 base::WriteBigEndian(hash_bytes, next_hash); | |
128 result.insert(std::string(hash_bytes, 8)); | |
129 curr_hash = next_hash; | |
130 } | |
131 | |
132 uncompressed_list->swap(result); | |
133 return true; | |
134 } | |
135 | |
136 } // namespace internal | |
137 | |
138 void SetEVWhitelistFromFile(const base::FilePath& compressed_whitelist_file) { | |
139 VLOG(1) << "Setting EV whitelist from file: " | |
140 << compressed_whitelist_file.value(); | |
141 std::string compressed_list; | |
142 if (!base::ReadFileToString(compressed_whitelist_file, &compressed_list)) { | |
143 VLOG(1) << "Failed reading from " << compressed_whitelist_file.value(); | |
144 return; | |
145 } | |
146 | |
147 std::set<std::string> uncompressed_list; | |
148 if (!internal::UncompressEVWhitelist(compressed_list, &uncompressed_list)) { | |
149 VLOG(1) << "Failed uncompressing."; | |
150 return; | |
151 } | |
152 VLOG(1) << "Uncompressing succeeded, hashes: " << uncompressed_list.size(); | |
153 | |
154 internal::SetEVWhitelistData(uncompressed_list); | |
155 } | |
156 | |
157 bool IsCertificateHashInWhitelist(const std::string& cert_hash) { | |
158 return g_current_ev_whitelist.Get().find(cert_hash) != | |
159 g_current_ev_whitelist.Get().end(); | |
160 } | |
161 | |
162 } // namespace ct | |
163 | |
164 } // namespace net | |
165 | |
166 | |
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