components/webcrypto/algorithms/aes_gcm.cc

   1 // Copyright 2014 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 <openssl/evp.h>
   6 #include <vector>
   7
   8 #include "base/logging.h"
   9 #include "base/stl_util.h"
  10 #include "components/webcrypto/algorithms/aes.h"
  11 #include "components/webcrypto/algorithms/util_openssl.h"
  12 #include "components/webcrypto/crypto_data.h"
  13 #include "components/webcrypto/key.h"
  14 #include "components/webcrypto/status.h"
  15 #include "components/webcrypto/webcrypto_util.h"
  16 #include "crypto/openssl_util.h"
  17 #include "crypto/scoped_openssl_types.h"
  18 #include "third_party/WebKit/public/platform/WebCryptoAlgorithmParams.h"
  19
  20 namespace webcrypto {
  21
  22 namespace {
  23
  24 const EVP_AEAD* GetAesGcmAlgorithmFromKeySize(size_t key_size_bytes) {
  25   switch (key_size_bytes) {
  26     case 16:
  27       return EVP_aead_aes_128_gcm();
  28     case 32:
  29       return EVP_aead_aes_256_gcm();
  30     default:
  31       return NULL;
  32   }
  33 }
  34
  35 Status AesGcmEncryptDecrypt(EncryptOrDecrypt mode,
  36                             const blink::WebCryptoAlgorithm& algorithm,
  37                             const blink::WebCryptoKey& key,
  38                             const CryptoData& data,
  39                             std::vector<uint8_t>* buffer) {
  40   const std::vector<uint8_t>& raw_key = GetSymmetricKeyData(key);
  41   const blink::WebCryptoAesGcmParams* params = algorithm.aesGcmParams();
  42
  43   unsigned int tag_length_bits;
  44   Status status = GetAesGcmTagLengthInBits(params, &tag_length_bits);
  45   if (status.IsError())
  46     return status;
  47
  48   return AeadEncryptDecrypt(
  49       mode, raw_key, data, tag_length_bits / 8, CryptoData(params->iv()),
  50       CryptoData(params->optionalAdditionalData()),
  51       GetAesGcmAlgorithmFromKeySize(raw_key.size()), buffer);
  52 }
  53
  54 class AesGcmImplementation : public AesAlgorithm {
  55  public:
  56   AesGcmImplementation() : AesAlgorithm("GCM") {}
  57
  58   Status Encrypt(const blink::WebCryptoAlgorithm& algorithm,
  59                  const blink::WebCryptoKey& key,
  60                  const CryptoData& data,
  61                  std::vector<uint8_t>* buffer) const override {
  62     return AesGcmEncryptDecrypt(ENCRYPT, algorithm, key, data, buffer);
  63   }
  64
  65   Status Decrypt(const blink::WebCryptoAlgorithm& algorithm,
  66                  const blink::WebCryptoKey& key,
  67                  const CryptoData& data,
  68                  std::vector<uint8_t>* buffer) const override {
  69     return AesGcmEncryptDecrypt(DECRYPT, algorithm, key, data, buffer);
  70   }
  71 };
  72
  73 }  // namespace
  74
  75 scoped_ptr<AlgorithmImplementation> CreateAesGcmImplementation() {
  76   return make_scoped_ptr(new AesGcmImplementation);
  77 }
  78
  79 }  // namespace webcrypto