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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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