components/webcrypto/algorithms/aes.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 "components/webcrypto/algorithms/aes.h"
   6
   7 #include "base/logging.h"
   8 #include "components/webcrypto/algorithms/util_openssl.h"
   9 #include "components/webcrypto/crypto_data.h"
  10 #include "components/webcrypto/jwk.h"
  11 #include "components/webcrypto/key.h"
  12 #include "components/webcrypto/status.h"
  13 #include "components/webcrypto/webcrypto_util.h"
  14 #include "third_party/WebKit/public/platform/WebCryptoKeyAlgorithm.h"
  15
  16 namespace webcrypto {
  17
  18 namespace {
  19
  20 // Creates an AES algorithm name for the given key size (in bytes). For
  21 // instance "A128CBC" is the result of suffix="CBC", keylen_bytes=16.
  22 std::string MakeJwkAesAlgorithmName(const std::string& suffix,
  23                                     size_t keylen_bytes) {
  24   if (keylen_bytes == 16)
  25     return std::string("A128") + suffix;
  26   if (keylen_bytes == 24)
  27     return std::string("A192") + suffix;
  28   if (keylen_bytes == 32)
  29     return std::string("A256") + suffix;
  30   return std::string();
  31 }
  32
  33 }  // namespace
  34
  35 AesAlgorithm::AesAlgorithm(blink::WebCryptoKeyUsageMask all_key_usages,
  36                            const std::string& jwk_suffix)
  37     : all_key_usages_(all_key_usages), jwk_suffix_(jwk_suffix) {
  38 }
  39
  40 AesAlgorithm::AesAlgorithm(const std::string& jwk_suffix)
  41     : all_key_usages_(blink::WebCryptoKeyUsageEncrypt |
  42                       blink::WebCryptoKeyUsageDecrypt |
  43                       blink::WebCryptoKeyUsageWrapKey |
  44                       blink::WebCryptoKeyUsageUnwrapKey),
  45       jwk_suffix_(jwk_suffix) {
  46 }
  47
  48 Status AesAlgorithm::GenerateKey(const blink::WebCryptoAlgorithm& algorithm,
  49                                  bool extractable,
  50                                  blink::WebCryptoKeyUsageMask usages,
  51                                  GenerateKeyResult* result) const {
  52   Status status = CheckKeyCreationUsages(all_key_usages_, usages, false);
  53   if (status.IsError())
  54     return status;
  55
  56   unsigned int keylen_bits;
  57   status = GetAesKeyGenLengthInBits(algorithm.aesKeyGenParams(), &keylen_bits);
  58   if (status.IsError())
  59     return status;
  60
  61   return GenerateWebCryptoSecretKey(
  62       blink::WebCryptoKeyAlgorithm::createAes(algorithm.id(), keylen_bits),
  63       extractable, usages, keylen_bits, result);
  64 }
  65
  66 Status AesAlgorithm::VerifyKeyUsagesBeforeImportKey(
  67     blink::WebCryptoKeyFormat format,
  68     blink::WebCryptoKeyUsageMask usages) const {
  69   switch (format) {
  70     case blink::WebCryptoKeyFormatRaw:
  71     case blink::WebCryptoKeyFormatJwk:
  72       return CheckKeyCreationUsages(all_key_usages_, usages, false);
  73     default:
  74       return Status::ErrorUnsupportedImportKeyFormat();
  75   }
  76 }
  77
  78 Status AesAlgorithm::ImportKeyRaw(const CryptoData& key_data,
  79                                   const blink::WebCryptoAlgorithm& algorithm,
  80                                   bool extractable,
  81                                   blink::WebCryptoKeyUsageMask usages,
  82                                   blink::WebCryptoKey* key) const {
  83   const unsigned int keylen_bytes = key_data.byte_length();
  84   Status status = VerifyAesKeyLengthForImport(keylen_bytes);
  85   if (status.IsError())
  86     return status;
  87
  88   // No possibility of overflow.
  89   unsigned int keylen_bits = keylen_bytes * 8;
  90
  91   return CreateWebCryptoSecretKey(
  92       key_data,
  93       blink::WebCryptoKeyAlgorithm::createAes(algorithm.id(), keylen_bits),
  94       extractable, usages, key);
  95 }
  96
  97 Status AesAlgorithm::ImportKeyJwk(const CryptoData& key_data,
  98                                   const blink::WebCryptoAlgorithm& algorithm,
  99                                   bool extractable,
 100                                   blink::WebCryptoKeyUsageMask usages,
 101                                   blink::WebCryptoKey* key) const {
 102   std::vector<uint8_t> raw_data;
 103   JwkReader jwk;
 104   Status status = ReadSecretKeyNoExpectedAlg(key_data, extractable, usages,
 105                                              &raw_data, &jwk);
 106   if (status.IsError())
 107     return status;
 108
 109   bool has_jwk_alg;
 110   std::string jwk_alg;
 111   status = jwk.GetAlg(&jwk_alg, &has_jwk_alg);
 112   if (status.IsError())
 113     return status;
 114
 115   if (has_jwk_alg) {
 116     std::string expected_algorithm_name =
 117         MakeJwkAesAlgorithmName(jwk_suffix_, raw_data.size());
 118
 119     if (jwk_alg != expected_algorithm_name) {
 120       // Give a different error message if the key length was wrong.
 121       if (jwk_alg == MakeJwkAesAlgorithmName(jwk_suffix_, 16) ||
 122           jwk_alg == MakeJwkAesAlgorithmName(jwk_suffix_, 24) ||
 123           jwk_alg == MakeJwkAesAlgorithmName(jwk_suffix_, 32)) {
 124         return Status::ErrorJwkIncorrectKeyLength();
 125       }
 126       return Status::ErrorJwkAlgorithmInconsistent();
 127     }
 128   }
 129
 130   return ImportKeyRaw(CryptoData(raw_data), algorithm, extractable, usages,
 131                       key);
 132 }
 133
 134 Status AesAlgorithm::ExportKeyRaw(const blink::WebCryptoKey& key,
 135                                   std::vector<uint8_t>* buffer) const {
 136   *buffer = GetSymmetricKeyData(key);
 137   return Status::Success();
 138 }
 139
 140 Status AesAlgorithm::ExportKeyJwk(const blink::WebCryptoKey& key,
 141                                   std::vector<uint8_t>* buffer) const {
 142   const std::vector<uint8_t>& raw_data = GetSymmetricKeyData(key);
 143
 144   WriteSecretKeyJwk(CryptoData(raw_data),
 145                     MakeJwkAesAlgorithmName(jwk_suffix_, raw_data.size()),
 146                     key.extractable(), key.usages(), buffer);
 147
 148   return Status::Success();
 149 }
 150
 151 Status AesAlgorithm::DeserializeKeyForClone(
 152     const blink::WebCryptoKeyAlgorithm& algorithm,
 153     blink::WebCryptoKeyType type,
 154     bool extractable,
 155     blink::WebCryptoKeyUsageMask usages,
 156     const CryptoData& key_data,
 157     blink::WebCryptoKey* key) const {
 158   return ImportKeyRaw(key_data, CreateAlgorithm(algorithm.id()), extractable,
 159                       usages, key);
 160 }
 161
 162 Status AesAlgorithm::GetKeyLength(
 163     const blink::WebCryptoAlgorithm& key_length_algorithm,
 164     bool* has_length_bits,
 165     unsigned int* length_bits) const {
 166   return GetAesKeyLength(key_length_algorithm, has_length_bits, length_bits);
 167 }
 168
 169 }  // namespace webcrypto