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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/aead_base_encrypter.h" | |
6 | |
7 #include <openssl/err.h> | |
8 #include <openssl/evp.h> | |
9 #include <string.h> | |
10 | |
11 #include "base/memory/scoped_ptr.h" | |
12 | |
13 using base::StringPiece; | |
14 | |
15 namespace net { | |
16 | |
17 namespace { | |
18 | |
19 // In debug builds only, log OpenSSL error stack. Then clear OpenSSL error | |
20 // stack. | |
21 void DLogOpenSslErrors() { | |
22 #ifdef NDEBUG | |
23 while (ERR_get_error()) {} | |
24 #else | |
25 while (unsigned long error = ERR_get_error()) { | |
26 char buf[120]; | |
27 ERR_error_string_n(error, buf, arraysize(buf)); | |
28 DLOG(ERROR) << "OpenSSL error: " << buf; | |
29 } | |
30 #endif | |
31 } | |
32 | |
33 } // namespace | |
34 | |
35 AeadBaseEncrypter::AeadBaseEncrypter(const EVP_AEAD* aead_alg, | |
36 size_t key_size, | |
37 size_t auth_tag_size, | |
38 size_t nonce_prefix_size) | |
39 : aead_alg_(aead_alg), | |
40 key_size_(key_size), | |
41 auth_tag_size_(auth_tag_size), | |
42 nonce_prefix_size_(nonce_prefix_size) { | |
43 DCHECK_LE(key_size_, sizeof(key_)); | |
44 DCHECK_LE(nonce_prefix_size_, sizeof(nonce_prefix_)); | |
45 } | |
46 | |
47 AeadBaseEncrypter::~AeadBaseEncrypter() {} | |
48 | |
49 bool AeadBaseEncrypter::SetKey(StringPiece key) { | |
50 DCHECK_EQ(key.size(), key_size_); | |
51 if (key.size() != key_size_) { | |
52 return false; | |
53 } | |
54 memcpy(key_, key.data(), key.size()); | |
55 | |
56 EVP_AEAD_CTX_cleanup(ctx_.get()); | |
57 | |
58 if (!EVP_AEAD_CTX_init(ctx_.get(), aead_alg_, key_, key_size_, | |
59 auth_tag_size_, nullptr)) { | |
60 DLogOpenSslErrors(); | |
61 return false; | |
62 } | |
63 | |
64 return true; | |
65 } | |
66 | |
67 bool AeadBaseEncrypter::SetNoncePrefix(StringPiece nonce_prefix) { | |
68 DCHECK_EQ(nonce_prefix.size(), nonce_prefix_size_); | |
69 if (nonce_prefix.size() != nonce_prefix_size_) { | |
70 return false; | |
71 } | |
72 memcpy(nonce_prefix_, nonce_prefix.data(), nonce_prefix.size()); | |
73 return true; | |
74 } | |
75 | |
76 bool AeadBaseEncrypter::Encrypt(StringPiece nonce, | |
77 StringPiece associated_data, | |
78 StringPiece plaintext, | |
79 unsigned char* output) { | |
80 if (nonce.size() != nonce_prefix_size_ + sizeof(QuicPacketSequenceNumber)) { | |
81 return false; | |
82 } | |
83 | |
84 size_t ciphertext_len; | |
85 if (!EVP_AEAD_CTX_seal( | |
86 ctx_.get(), output, &ciphertext_len, | |
87 plaintext.size() + auth_tag_size_, | |
88 reinterpret_cast<const uint8_t*>(nonce.data()), nonce.size(), | |
89 reinterpret_cast<const uint8_t*>(plaintext.data()), plaintext.size(), | |
90 reinterpret_cast<const uint8_t*>(associated_data.data()), | |
91 associated_data.size())) { | |
92 DLogOpenSslErrors(); | |
93 return false; | |
94 } | |
95 | |
96 return true; | |
97 } | |
98 | |
99 bool AeadBaseEncrypter::EncryptPacket(QuicPacketSequenceNumber sequence_number, | |
100 StringPiece associated_data, | |
101 StringPiece plaintext, | |
102 char* output, | |
103 size_t* output_length, | |
104 size_t max_output_length) { | |
105 size_t ciphertext_size = GetCiphertextSize(plaintext.length()); | |
106 if (max_output_length < ciphertext_size) { | |
107 return false; | |
108 } | |
109 // TODO(ianswett): Introduce a check to ensure that we don't encrypt with the | |
110 // same sequence number twice. | |
111 const size_t nonce_size = nonce_prefix_size_ + sizeof(sequence_number); | |
112 memcpy(output, nonce_prefix_, nonce_prefix_size_); | |
113 memcpy(output + nonce_prefix_size_, &sequence_number, | |
114 sizeof(sequence_number)); | |
115 if (!Encrypt(StringPiece(output, nonce_size), associated_data, plaintext, | |
116 reinterpret_cast<unsigned char*>(output))) { | |
117 return false; | |
118 } | |
119 *output_length = ciphertext_size; | |
120 return true; | |
121 } | |
122 | |
123 size_t AeadBaseEncrypter::GetKeySize() const { return key_size_; } | |
124 | |
125 size_t AeadBaseEncrypter::GetNoncePrefixSize() const { | |
126 return nonce_prefix_size_; | |
127 } | |
128 | |
129 size_t AeadBaseEncrypter::GetMaxPlaintextSize(size_t ciphertext_size) const { | |
130 return ciphertext_size - auth_tag_size_; | |
131 } | |
132 | |
133 size_t AeadBaseEncrypter::GetCiphertextSize(size_t plaintext_size) const { | |
134 return plaintext_size + auth_tag_size_; | |
135 } | |
136 | |
137 StringPiece AeadBaseEncrypter::GetKey() const { | |
138 return StringPiece(reinterpret_cast<const char*>(key_), key_size_); | |
139 } | |
140 | |
141 StringPiece AeadBaseEncrypter::GetNoncePrefix() const { | |
142 if (nonce_prefix_size_ == 0) { | |
143 return StringPiece(); | |
144 } | |
145 return StringPiece(reinterpret_cast<const char*>(nonce_prefix_), | |
146 nonce_prefix_size_); | |
147 } | |
148 | |
149 } // namespace net | |
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