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1 // Copyright (c) 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 "net/quic/crypto/crypto_utils.h" | |
6 | |
7 #include "crypto/hkdf.h" | |
8 #include "net/base/net_util.h" | |
9 #include "net/quic/crypto/crypto_handshake.h" | |
10 #include "net/quic/crypto/crypto_protocol.h" | |
11 #include "net/quic/crypto/quic_decrypter.h" | |
12 #include "net/quic/crypto/quic_encrypter.h" | |
13 #include "net/quic/crypto/quic_random.h" | |
14 #include "net/quic/quic_time.h" | |
15 #include "url/url_canon.h" | |
16 | |
17 using base::StringPiece; | |
18 using std::numeric_limits; | |
19 using std::string; | |
20 | |
21 namespace net { | |
22 | |
23 // static | |
24 void CryptoUtils::GenerateNonce(QuicWallTime now, | |
25 QuicRandom* random_generator, | |
26 StringPiece orbit, | |
27 string* nonce) { | |
28 // a 4-byte timestamp + 28 random bytes. | |
29 nonce->reserve(kNonceSize); | |
30 nonce->resize(kNonceSize); | |
31 | |
32 uint32 gmt_unix_time = static_cast<uint32>(now.ToUNIXSeconds()); | |
33 // The time in the nonce must be encoded in big-endian because the | |
34 // strike-register depends on the nonces being ordered by time. | |
35 (*nonce)[0] = static_cast<char>(gmt_unix_time >> 24); | |
36 (*nonce)[1] = static_cast<char>(gmt_unix_time >> 16); | |
37 (*nonce)[2] = static_cast<char>(gmt_unix_time >> 8); | |
38 (*nonce)[3] = static_cast<char>(gmt_unix_time); | |
39 size_t bytes_written = 4; | |
40 | |
41 if (orbit.size() == 8) { | |
42 memcpy(&(*nonce)[bytes_written], orbit.data(), orbit.size()); | |
43 bytes_written += orbit.size(); | |
44 } | |
45 | |
46 random_generator->RandBytes(&(*nonce)[bytes_written], | |
47 kNonceSize - bytes_written); | |
48 } | |
49 | |
50 // static | |
51 bool CryptoUtils::IsValidSNI(StringPiece sni) { | |
52 // TODO(rtenneti): Support RFC2396 hostname. | |
53 // NOTE: Microsoft does NOT enforce this spec, so if we throw away hostnames | |
54 // based on the above spec, we may be losing some hostnames that windows | |
55 // would consider valid. By far the most common hostname character NOT | |
56 // accepted by the above spec is '_'. | |
57 url::CanonHostInfo host_info; | |
58 string canonicalized_host(CanonicalizeHost(sni.as_string(), &host_info)); | |
59 return !host_info.IsIPAddress() && | |
60 IsCanonicalizedHostCompliant(canonicalized_host) && | |
61 sni.find_last_of('.') != string::npos; | |
62 } | |
63 | |
64 // static | |
65 string CryptoUtils::NormalizeHostname(const char* hostname) { | |
66 url::CanonHostInfo host_info; | |
67 string host(CanonicalizeHost(hostname, &host_info)); | |
68 | |
69 // Walk backwards over the string, stopping at the first trailing dot. | |
70 size_t host_end = host.length(); | |
71 while (host_end != 0 && host[host_end - 1] == '.') { | |
72 host_end--; | |
73 } | |
74 | |
75 // Erase the trailing dots. | |
76 if (host_end != host.length()) { | |
77 host.erase(host_end, host.length() - host_end); | |
78 } | |
79 return host; | |
80 } | |
81 | |
82 // static | |
83 bool CryptoUtils::DeriveKeys(StringPiece premaster_secret, | |
84 QuicTag aead, | |
85 StringPiece client_nonce, | |
86 StringPiece server_nonce, | |
87 const string& hkdf_input, | |
88 Perspective perspective, | |
89 CrypterPair* crypters, | |
90 string* subkey_secret) { | |
91 crypters->encrypter.reset(QuicEncrypter::Create(aead)); | |
92 crypters->decrypter.reset(QuicDecrypter::Create(aead)); | |
93 size_t key_bytes = crypters->encrypter->GetKeySize(); | |
94 size_t nonce_prefix_bytes = crypters->encrypter->GetNoncePrefixSize(); | |
95 size_t subkey_secret_bytes = | |
96 subkey_secret == nullptr ? 0 : premaster_secret.length(); | |
97 | |
98 StringPiece nonce = client_nonce; | |
99 string nonce_storage; | |
100 if (!server_nonce.empty()) { | |
101 nonce_storage = client_nonce.as_string() + server_nonce.as_string(); | |
102 nonce = nonce_storage; | |
103 } | |
104 | |
105 crypto::HKDF hkdf(premaster_secret, nonce, hkdf_input, key_bytes, | |
106 nonce_prefix_bytes, subkey_secret_bytes); | |
107 if (perspective == SERVER) { | |
108 if (!crypters->encrypter->SetKey(hkdf.server_write_key()) || | |
109 !crypters->encrypter->SetNoncePrefix(hkdf.server_write_iv()) || | |
110 !crypters->decrypter->SetKey(hkdf.client_write_key()) || | |
111 !crypters->decrypter->SetNoncePrefix(hkdf.client_write_iv())) { | |
112 return false; | |
113 } | |
114 } else { | |
115 if (!crypters->encrypter->SetKey(hkdf.client_write_key()) || | |
116 !crypters->encrypter->SetNoncePrefix(hkdf.client_write_iv()) || | |
117 !crypters->decrypter->SetKey(hkdf.server_write_key()) || | |
118 !crypters->decrypter->SetNoncePrefix(hkdf.server_write_iv())) { | |
119 return false; | |
120 } | |
121 } | |
122 if (subkey_secret != nullptr) { | |
123 hkdf.subkey_secret().CopyToString(subkey_secret); | |
124 } | |
125 | |
126 return true; | |
127 } | |
128 | |
129 // static | |
130 bool CryptoUtils::ExportKeyingMaterial(StringPiece subkey_secret, | |
131 StringPiece label, | |
132 StringPiece context, | |
133 size_t result_len, | |
134 string* result) { | |
135 for (size_t i = 0; i < label.length(); i++) { | |
136 if (label[i] == '\0') { | |
137 LOG(ERROR) << "ExportKeyingMaterial label may not contain NULs"; | |
138 return false; | |
139 } | |
140 } | |
141 // Create HKDF info input: null-terminated label + length-prefixed context | |
142 if (context.length() >= numeric_limits<uint32>::max()) { | |
143 LOG(ERROR) << "Context value longer than 2^32"; | |
144 return false; | |
145 } | |
146 uint32 context_length = static_cast<uint32>(context.length()); | |
147 string info = label.as_string(); | |
148 info.push_back('\0'); | |
149 info.append(reinterpret_cast<char*>(&context_length), sizeof(context_length)); | |
150 info.append(context.data(), context.length()); | |
151 | |
152 crypto::HKDF hkdf(subkey_secret, | |
153 StringPiece() /* no salt */, | |
154 info, | |
155 result_len, | |
156 0 /* no fixed IV */, | |
157 0 /* no subkey secret */); | |
158 hkdf.client_write_key().CopyToString(result); | |
159 return true; | |
160 } | |
161 | |
162 } // namespace net | |
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