content/child/webcrypto/webcrypto_util.h

   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 #ifndef CONTENT_CHILD_WEBCRYPTO_WEBCRYPTO_UTIL_H_
   6 #define CONTENT_CHILD_WEBCRYPTO_WEBCRYPTO_UTIL_H_
   7
   8 #include <stdint.h>
   9 #include <string>
  10
  11 #include "base/values.h"
  12 #include "content/common/content_export.h"
  13 #include "third_party/WebKit/public/platform/WebCryptoAlgorithm.h"
  14 #include "third_party/WebKit/public/platform/WebCryptoKey.h"
  15
  16 namespace content {
  17
  18 namespace webcrypto {
  19
  20 class Status;
  21
  22 // Creates a WebCryptoAlgorithm without any parameters.
  23 CONTENT_EXPORT blink::WebCryptoAlgorithm CreateAlgorithm(
  24     blink::WebCryptoAlgorithmId id);
  25
  26 // Creates an HMAC import algorithm whose inner hash algorithm is determined by
  27 // the specified algorithm ID. It is an error to call this method with a hash
  28 // algorithm that is not SHA*.
  29 CONTENT_EXPORT blink::WebCryptoAlgorithm CreateHmacImportAlgorithm(
  30     blink::WebCryptoAlgorithmId hash_id,
  31     unsigned int length_bits);
  32
  33 // Same as above but without specifying a length.
  34 CONTENT_EXPORT blink::WebCryptoAlgorithm CreateHmacImportAlgorithmNoLength(
  35     blink::WebCryptoAlgorithmId hash_id);
  36
  37 // Creates an import algorithm for RSA algorithms that take a hash.
  38 // It is an error to call this with a hash_id that is not a SHA*.
  39 CONTENT_EXPORT blink::WebCryptoAlgorithm CreateRsaHashedImportAlgorithm(
  40     blink::WebCryptoAlgorithmId id,
  41     blink::WebCryptoAlgorithmId hash_id);
  42
  43 // Creates an import algorithm for EC keys.
  44 CONTENT_EXPORT blink::WebCryptoAlgorithm CreateEcImportAlgorithm(
  45     blink::WebCryptoAlgorithmId id,
  46     blink::WebCryptoNamedCurve named_curve);
  47
  48 // Returns true if the set bits in b make up a subset of the set bits in a.
  49 bool ContainsKeyUsages(blink::WebCryptoKeyUsageMask a,
  50                        blink::WebCryptoKeyUsageMask b);
  51
  52 bool KeyUsageAllows(const blink::WebCryptoKey& key,
  53                     const blink::WebCryptoKeyUsage usage);
  54
  55 Status GetAesGcmTagLengthInBits(const blink::WebCryptoAesGcmParams* params,
  56                                 unsigned int* tag_length_bits);
  57
  58 Status GetAesKeyGenLengthInBits(const blink::WebCryptoAesKeyGenParams* params,
  59                                 unsigned int* keylen_bits);
  60
  61 Status GetHmacKeyGenLengthInBits(const blink::WebCryptoHmacKeyGenParams* params,
  62                                  unsigned int* keylen_bits);
  63
  64 // Gets the requested key length in bits for an HMAC import operation.
  65 Status GetHmacImportKeyLengthBits(
  66     const blink::WebCryptoHmacImportParams* params,
  67     unsigned int key_data_byte_length,
  68     unsigned int* keylen_bits);
  69
  70 Status VerifyAesKeyLengthForImport(unsigned int keylen_bytes);
  71
  72 Status CheckKeyCreationUsages(blink::WebCryptoKeyUsageMask all_possible_usages,
  73                               blink::WebCryptoKeyUsageMask actual_usages,
  74                               bool allow_empty_usages);
  75
  76 // Extracts the public exponent and modulus length from the Blink parameters.
  77 // On success it is guaranteed that:
  78 //   * public_exponent is either 3 or 65537
  79 //   * modulus_length_bits is a multiple of 8
  80 //   * modulus_length is >= 256
  81 //   * modulus_length is <= 16K
  82 Status GetRsaKeyGenParameters(
  83     const blink::WebCryptoRsaHashedKeyGenParams* params,
  84     unsigned int* public_exponent,
  85     unsigned int* modulus_length_bits);
  86
  87 // Verifies that |usages| is valid when importing a key of the given format.
  88 Status VerifyUsagesBeforeImportAsymmetricKey(
  89     blink::WebCryptoKeyFormat format,
  90     blink::WebCryptoKeyUsageMask all_public_key_usages,
  91     blink::WebCryptoKeyUsageMask all_private_key_usages,
  92     blink::WebCryptoKeyUsageMask usages);
  93
  94 // Truncates an octet string to a particular bit length. This is accomplished by
  95 // resizing to the closest byte length, and then zero-ing the unused
  96 // least-significant bits of the final byte.
  97 //
  98 // It is an error to call this function with a bit length that is larger than
  99 // that of |bytes|.
 100 //
 101 // TODO(eroman): This operation is not yet defined by the WebCrypto spec,
 102 // however this is a reasonable interpretation:
 103 // https://www.w3.org/Bugs/Public/show_bug.cgi?id=27402
 104 void TruncateToBitLength(size_t length_bits, std::vector<uint8_t>* bytes);
 105
 106 // Rounds a bit count (up) to the nearest byte count.
 107 //
 108 // This is mathematically equivalent to (x + 7) / 8, however has no
 109 // possibility of integer overflow.
 110 template <typename T>
 111 T NumBitsToBytes(T x) {
 112   return (x / 8) + (7 + (x % 8)) / 8;
 113 }
 114
 115 // The "get key length" operation for AES keys.
 116 Status GetAesKeyLength(const blink::WebCryptoAlgorithm& key_length_algorithm,
 117                        bool* has_length_bits,
 118                        unsigned int* length_bits);
 119
 120 // The "get key length" operation for HMAC keys.
 121 Status GetHmacKeyLength(const blink::WebCryptoAlgorithm& key_length_algorithm,
 122                         bool* has_length_bits,
 123                         unsigned int* length_bits);
 124
 125 // Splits the combined usages given to GenerateKey() into the respective usages
 126 // for the public key and private key. Returns an error if the usages are
 127 // invalid.
 128 Status GetUsagesForGenerateAsymmetricKey(
 129     blink::WebCryptoKeyUsageMask combined_usages,
 130     blink::WebCryptoKeyUsageMask all_public_usages,
 131     blink::WebCryptoKeyUsageMask all_private_usages,
 132     blink::WebCryptoKeyUsageMask* public_usages,
 133     blink::WebCryptoKeyUsageMask* private_usages);
 134
 135 }  // namespace webcrypto
 136
 137 }  // namespace content
 138
 139 #endif  // CONTENT_CHILD_WEBCRYPTO_WEBCRYPTO_UTIL_H_