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| 1 // Copyright (c) 2011 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 "crypto/encryptor.h" | |
| 6 | |
| 7 #include <openssl/aes.h> | |
| 8 #include <openssl/evp.h> | |
| 9 #include <stddef.h> | |
| 10 #include <stdint.h> | |
| 11 | |
| 12 #include "base/logging.h" | |
| 13 #include "base/strings/string_util.h" | |
| 14 #include "crypto/openssl_util.h" | |
| 15 #include "crypto/symmetric_key.h" | |
| 16 | |
| 17 namespace crypto { | |
| 18 | |
| 19 namespace { | |
| 20 | |
| 21 const EVP_CIPHER* GetCipherForKey(SymmetricKey* key) { | |
| 22 switch (key->key().length()) { | |
| 23 case 16: return EVP_aes_128_cbc(); | |
| 24 case 32: return EVP_aes_256_cbc(); | |
| 25 default: return NULL; | |
| 26 } | |
| 27 } | |
| 28 | |
| 29 // On destruction this class will cleanup the ctx, and also clear the OpenSSL | |
| 30 // ERR stack as a convenience. | |
| 31 class ScopedCipherCTX { | |
| 32 public: | |
| 33 explicit ScopedCipherCTX() { | |
| 34 EVP_CIPHER_CTX_init(&ctx_); | |
| 35 } | |
| 36 ~ScopedCipherCTX() { | |
| 37 EVP_CIPHER_CTX_cleanup(&ctx_); | |
| 38 ClearOpenSSLERRStack(FROM_HERE); | |
| 39 } | |
| 40 EVP_CIPHER_CTX* get() { return &ctx_; } | |
| 41 | |
| 42 private: | |
| 43 EVP_CIPHER_CTX ctx_; | |
| 44 }; | |
| 45 | |
| 46 } // namespace | |
| 47 | |
| 48 Encryptor::Encryptor() | |
| 49 : key_(NULL), | |
| 50 mode_(CBC) { | |
| 51 } | |
| 52 | |
| 53 Encryptor::~Encryptor() { | |
| 54 } | |
| 55 | |
| 56 bool Encryptor::Init(SymmetricKey* key, | |
| 57 Mode mode, | |
| 58 const base::StringPiece& iv) { | |
| 59 DCHECK(key); | |
| 60 DCHECK(mode == CBC || mode == CTR); | |
| 61 | |
| 62 EnsureOpenSSLInit(); | |
| 63 if (mode == CBC && iv.size() != AES_BLOCK_SIZE) | |
| 64 return false; | |
| 65 | |
| 66 if (GetCipherForKey(key) == NULL) | |
| 67 return false; | |
| 68 | |
| 69 key_ = key; | |
| 70 mode_ = mode; | |
| 71 iv.CopyToString(&iv_); | |
| 72 return true; | |
| 73 } | |
| 74 | |
| 75 bool Encryptor::Encrypt(const base::StringPiece& plaintext, | |
| 76 std::string* ciphertext) { | |
| 77 CHECK(!plaintext.empty() || (mode_ == CBC)); | |
| 78 return (mode_ == CTR) ? | |
| 79 CryptCTR(true, plaintext, ciphertext) : | |
| 80 Crypt(true, plaintext, ciphertext); | |
| 81 } | |
| 82 | |
| 83 bool Encryptor::Decrypt(const base::StringPiece& ciphertext, | |
| 84 std::string* plaintext) { | |
| 85 CHECK(!ciphertext.empty()); | |
| 86 return (mode_ == CTR) ? | |
| 87 CryptCTR(false, ciphertext, plaintext) : | |
| 88 Crypt(false, ciphertext, plaintext); | |
| 89 } | |
| 90 | |
| 91 bool Encryptor::Crypt(bool do_encrypt, | |
| 92 const base::StringPiece& input, | |
| 93 std::string* output) { | |
| 94 DCHECK(key_); // Must call Init() before En/De-crypt. | |
| 95 // Work on the result in a local variable, and then only transfer it to | |
| 96 // |output| on success to ensure no partial data is returned. | |
| 97 std::string result; | |
| 98 output->clear(); | |
| 99 | |
| 100 const EVP_CIPHER* cipher = GetCipherForKey(key_); | |
| 101 DCHECK(cipher); // Already handled in Init(); | |
| 102 | |
| 103 const std::string& key = key_->key(); | |
| 104 DCHECK_EQ(EVP_CIPHER_iv_length(cipher), iv_.length()); | |
| 105 DCHECK_EQ(EVP_CIPHER_key_length(cipher), key.length()); | |
| 106 | |
| 107 ScopedCipherCTX ctx; | |
| 108 if (!EVP_CipherInit_ex( | |
| 109 ctx.get(), cipher, NULL, reinterpret_cast<const uint8_t*>(key.data()), | |
| 110 reinterpret_cast<const uint8_t*>(iv_.data()), do_encrypt)) | |
| 111 return false; | |
| 112 | |
| 113 // When encrypting, add another block size of space to allow for any padding. | |
| 114 const size_t output_size = input.size() + (do_encrypt ? iv_.size() : 0); | |
| 115 CHECK_GT(output_size, 0u); | |
| 116 CHECK_GT(output_size + 1, input.size()); | |
| 117 uint8_t* out_ptr = | |
| 118 reinterpret_cast<uint8_t*>(base::WriteInto(&result, output_size + 1)); | |
| 119 int out_len; | |
| 120 if (!EVP_CipherUpdate(ctx.get(), out_ptr, &out_len, | |
| 121 reinterpret_cast<const uint8_t*>(input.data()), | |
| 122 input.length())) | |
| 123 return false; | |
| 124 | |
| 125 // Write out the final block plus padding (if any) to the end of the data | |
| 126 // just written. | |
| 127 int tail_len; | |
| 128 if (!EVP_CipherFinal_ex(ctx.get(), out_ptr + out_len, &tail_len)) | |
| 129 return false; | |
| 130 | |
| 131 out_len += tail_len; | |
| 132 DCHECK_LE(out_len, static_cast<int>(output_size)); | |
| 133 result.resize(out_len); | |
| 134 | |
| 135 output->swap(result); | |
| 136 return true; | |
| 137 } | |
| 138 | |
| 139 bool Encryptor::CryptCTR(bool do_encrypt, | |
| 140 const base::StringPiece& input, | |
| 141 std::string* output) { | |
| 142 if (!counter_.get()) { | |
| 143 LOG(ERROR) << "Counter value not set in CTR mode."; | |
| 144 return false; | |
| 145 } | |
| 146 | |
| 147 AES_KEY aes_key; | |
| 148 if (AES_set_encrypt_key(reinterpret_cast<const uint8_t*>(key_->key().data()), | |
| 149 key_->key().size() * 8, &aes_key) != 0) { | |
| 150 return false; | |
| 151 } | |
| 152 | |
| 153 const size_t out_size = input.size(); | |
| 154 CHECK_GT(out_size, 0u); | |
| 155 CHECK_GT(out_size + 1, input.size()); | |
| 156 | |
| 157 std::string result; | |
| 158 uint8_t* out_ptr = | |
| 159 reinterpret_cast<uint8_t*>(base::WriteInto(&result, out_size + 1)); | |
| 160 | |
| 161 uint8_t ivec[AES_BLOCK_SIZE] = { 0 }; | |
| 162 uint8_t ecount_buf[AES_BLOCK_SIZE] = { 0 }; | |
| 163 unsigned int block_offset = 0; | |
| 164 | |
| 165 counter_->Write(ivec); | |
| 166 | |
| 167 AES_ctr128_encrypt(reinterpret_cast<const uint8_t*>(input.data()), out_ptr, | |
| 168 input.size(), &aes_key, ivec, ecount_buf, &block_offset); | |
| 169 | |
| 170 // AES_ctr128_encrypt() updates |ivec|. Update the |counter_| here. | |
| 171 SetCounter(base::StringPiece(reinterpret_cast<const char*>(ivec), | |
| 172 AES_BLOCK_SIZE)); | |
| 173 | |
| 174 output->swap(result); | |
| 175 return true; | |
| 176 } | |
| 177 | |
| 178 } // namespace crypto | |
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Chromium Code Reviews
Issue 1909513003:
Rename crypto/ *_openssl files (Closed)
Base URL: https://chromium.googlesource.com/chromium/src.git@master