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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/symmetric_key.h" |
| 6 |
| 7 #include <openssl/evp.h> |
| 8 #include <openssl/rand.h> |
| 9 |
| 10 #include <algorithm> |
| 11 |
| 12 #include "base/logging.h" |
| 13 #include "base/memory/scoped_ptr.h" |
| 14 #include "base/strings/string_util.h" |
| 15 #include "crypto/openssl_util.h" |
| 16 |
| 17 namespace crypto { |
| 18 |
| 19 SymmetricKey::~SymmetricKey() { |
| 20 std::fill(key_.begin(), key_.end(), '\0'); // Zero out the confidential key. |
| 21 } |
| 22 |
| 23 // static |
| 24 SymmetricKey* SymmetricKey::GenerateRandomKey(Algorithm algorithm, |
| 25 size_t key_size_in_bits) { |
| 26 DCHECK_EQ(AES, algorithm); |
| 27 |
| 28 // Whitelist supported key sizes to avoid accidentaly relying on |
| 29 // algorithms available in NSS but not BoringSSL and vice |
| 30 // versa. Note that BoringSSL does not support AES-192. |
| 31 if (key_size_in_bits != 128 && key_size_in_bits != 256) |
| 32 return NULL; |
| 33 |
| 34 size_t key_size_in_bytes = key_size_in_bits / 8; |
| 35 DCHECK_EQ(key_size_in_bits, key_size_in_bytes * 8); |
| 36 |
| 37 if (key_size_in_bytes == 0) |
| 38 return NULL; |
| 39 |
| 40 OpenSSLErrStackTracer err_tracer(FROM_HERE); |
| 41 scoped_ptr<SymmetricKey> key(new SymmetricKey); |
| 42 uint8* key_data = reinterpret_cast<uint8*>( |
| 43 base::WriteInto(&key->key_, key_size_in_bytes + 1)); |
| 44 |
| 45 int rv = RAND_bytes(key_data, static_cast<int>(key_size_in_bytes)); |
| 46 return rv == 1 ? key.release() : NULL; |
| 47 } |
| 48 |
| 49 // static |
| 50 SymmetricKey* SymmetricKey::DeriveKeyFromPassword(Algorithm algorithm, |
| 51 const std::string& password, |
| 52 const std::string& salt, |
| 53 size_t iterations, |
| 54 size_t key_size_in_bits) { |
| 55 DCHECK(algorithm == AES || algorithm == HMAC_SHA1); |
| 56 |
| 57 if (algorithm == AES) { |
| 58 // Whitelist supported key sizes to avoid accidentaly relying on |
| 59 // algorithms available in NSS but not BoringSSL and vice |
| 60 // versa. Note that BoringSSL does not support AES-192. |
| 61 if (key_size_in_bits != 128 && key_size_in_bits != 256) |
| 62 return NULL; |
| 63 } |
| 64 |
| 65 size_t key_size_in_bytes = key_size_in_bits / 8; |
| 66 DCHECK_EQ(key_size_in_bits, key_size_in_bytes * 8); |
| 67 |
| 68 if (key_size_in_bytes == 0) |
| 69 return NULL; |
| 70 |
| 71 OpenSSLErrStackTracer err_tracer(FROM_HERE); |
| 72 scoped_ptr<SymmetricKey> key(new SymmetricKey); |
| 73 uint8* key_data = reinterpret_cast<uint8*>( |
| 74 base::WriteInto(&key->key_, key_size_in_bytes + 1)); |
| 75 int rv = PKCS5_PBKDF2_HMAC_SHA1(password.data(), password.length(), |
| 76 reinterpret_cast<const uint8*>(salt.data()), |
| 77 salt.length(), iterations, |
| 78 static_cast<int>(key_size_in_bytes), |
| 79 key_data); |
| 80 return rv == 1 ? key.release() : NULL; |
| 81 } |
| 82 |
| 83 // static |
| 84 SymmetricKey* SymmetricKey::Import(Algorithm algorithm, |
| 85 const std::string& raw_key) { |
| 86 if (algorithm == AES) { |
| 87 // Whitelist supported key sizes to avoid accidentaly relying on |
| 88 // algorithms available in NSS but not BoringSSL and vice |
| 89 // versa. Note that BoringSSL does not support AES-192. |
| 90 if (raw_key.size() != 128/8 && raw_key.size() != 256/8) |
| 91 return NULL; |
| 92 } |
| 93 |
| 94 scoped_ptr<SymmetricKey> key(new SymmetricKey); |
| 95 key->key_ = raw_key; |
| 96 return key.release(); |
| 97 } |
| 98 |
| 99 bool SymmetricKey::GetRawKey(std::string* raw_key) { |
| 100 *raw_key = key_; |
| 101 return true; |
| 102 } |
| 103 |
| 104 } // namespace crypto |
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