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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_decrypter.h" | |
6 | |
7 #include <openssl/err.h> | |
8 #include <openssl/evp.h> | |
9 | |
10 #include "base/memory/scoped_ptr.h" | |
11 | |
12 using base::StringPiece; | |
13 | |
14 namespace net { | |
15 | |
16 namespace { | |
17 | |
18 // Clear OpenSSL error stack. | |
19 void ClearOpenSslErrors() { | |
20 while (ERR_get_error()) {} | |
21 } | |
22 | |
23 // In debug builds only, log OpenSSL error stack. Then clear OpenSSL error | |
24 // stack. | |
25 void DLogOpenSslErrors() { | |
26 #ifdef NDEBUG | |
27 ClearOpenSslErrors(); | |
28 #else | |
29 while (unsigned long error = ERR_get_error()) { | |
30 char buf[120]; | |
31 ERR_error_string_n(error, buf, arraysize(buf)); | |
32 DLOG(ERROR) << "OpenSSL error: " << buf; | |
33 } | |
34 #endif | |
35 } | |
36 | |
37 } // namespace | |
38 | |
39 AeadBaseDecrypter::AeadBaseDecrypter(const EVP_AEAD* aead_alg, | |
40 size_t key_size, | |
41 size_t auth_tag_size, | |
42 size_t nonce_prefix_size) | |
43 : aead_alg_(aead_alg), | |
44 key_size_(key_size), | |
45 auth_tag_size_(auth_tag_size), | |
46 nonce_prefix_size_(nonce_prefix_size) { | |
47 DCHECK_LE(key_size_, sizeof(key_)); | |
48 DCHECK_LE(nonce_prefix_size_, sizeof(nonce_prefix_)); | |
49 } | |
50 | |
51 AeadBaseDecrypter::~AeadBaseDecrypter() {} | |
52 | |
53 bool AeadBaseDecrypter::SetKey(StringPiece key) { | |
54 DCHECK_EQ(key.size(), key_size_); | |
55 if (key.size() != key_size_) { | |
56 return false; | |
57 } | |
58 memcpy(key_, key.data(), key.size()); | |
59 | |
60 EVP_AEAD_CTX_cleanup(ctx_.get()); | |
61 if (!EVP_AEAD_CTX_init(ctx_.get(), aead_alg_, key_, key_size_, | |
62 auth_tag_size_, nullptr)) { | |
63 DLogOpenSslErrors(); | |
64 return false; | |
65 } | |
66 | |
67 return true; | |
68 } | |
69 | |
70 bool AeadBaseDecrypter::SetNoncePrefix(StringPiece nonce_prefix) { | |
71 DCHECK_EQ(nonce_prefix.size(), nonce_prefix_size_); | |
72 if (nonce_prefix.size() != nonce_prefix_size_) { | |
73 return false; | |
74 } | |
75 memcpy(nonce_prefix_, nonce_prefix.data(), nonce_prefix.size()); | |
76 return true; | |
77 } | |
78 | |
79 bool AeadBaseDecrypter::Decrypt(StringPiece nonce, | |
80 const StringPiece& associated_data, | |
81 const StringPiece& ciphertext, | |
82 uint8* output, | |
83 size_t* output_length, | |
84 size_t max_output_length) { | |
85 if (ciphertext.length() < auth_tag_size_ || | |
86 nonce.size() != nonce_prefix_size_ + sizeof(QuicPacketSequenceNumber)) { | |
87 return false; | |
88 } | |
89 | |
90 if (!EVP_AEAD_CTX_open( | |
91 ctx_.get(), output, output_length, max_output_length, | |
92 reinterpret_cast<const uint8_t*>(nonce.data()), nonce.size(), | |
93 reinterpret_cast<const uint8_t*>(ciphertext.data()), | |
94 ciphertext.size(), | |
95 reinterpret_cast<const uint8_t*>(associated_data.data()), | |
96 associated_data.size())) { | |
97 // Because QuicFramer does trial decryption, decryption errors are expected | |
98 // when encryption level changes. So we don't log decryption errors. | |
99 ClearOpenSslErrors(); | |
100 return false; | |
101 } | |
102 return true; | |
103 } | |
104 | |
105 bool AeadBaseDecrypter::DecryptPacket(QuicPacketSequenceNumber sequence_number, | |
106 const StringPiece& associated_data, | |
107 const StringPiece& ciphertext, | |
108 char* output, | |
109 size_t* output_length, | |
110 size_t max_output_length) { | |
111 if (ciphertext.length() < auth_tag_size_) { | |
112 return false; | |
113 } | |
114 | |
115 uint8 nonce[sizeof(nonce_prefix_) + sizeof(sequence_number)]; | |
116 const size_t nonce_size = nonce_prefix_size_ + sizeof(sequence_number); | |
117 DCHECK_LE(nonce_size, sizeof(nonce)); | |
118 memcpy(nonce, nonce_prefix_, nonce_prefix_size_); | |
119 memcpy(nonce + nonce_prefix_size_, &sequence_number, sizeof(sequence_number)); | |
120 return Decrypt(StringPiece(reinterpret_cast<char*>(nonce), nonce_size), | |
121 associated_data, ciphertext, reinterpret_cast<uint8*>(output), | |
122 output_length, max_output_length); | |
123 } | |
124 | |
125 StringPiece AeadBaseDecrypter::GetKey() const { | |
126 return StringPiece(reinterpret_cast<const char*>(key_), key_size_); | |
127 } | |
128 | |
129 StringPiece AeadBaseDecrypter::GetNoncePrefix() const { | |
130 if (nonce_prefix_size_ == 0) { | |
131 return StringPiece(); | |
132 } | |
133 return StringPiece(reinterpret_cast<const char*>(nonce_prefix_), | |
134 nonce_prefix_size_); | |
135 } | |
136 | |
137 } // namespace net | |
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