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 #include <stddef.h> 10 #include <stdint.h> 11 12 #include <algorithm> 13 14 #include "base/logging.h" 15 #include "base/memory/scoped_ptr.h" 16 #include "base/strings/string_util.h" 17 #include "crypto/openssl_util.h" 18 19 namespace crypto { 20 21 SymmetricKey::~SymmetricKey() { 22 std::fill(key_.begin(), key_.end(), '\0'); // Zero out the confidential key. 23 } 24 25 // static 26 SymmetricKey* SymmetricKey::GenerateRandomKey(Algorithm algorithm, 27 size_t key_size_in_bits) { 28 DCHECK_EQ(AES, algorithm); 29 30 // Whitelist supported key sizes to avoid accidentaly relying on 31 // algorithms available in NSS but not BoringSSL and vice 32 // versa. Note that BoringSSL does not support AES-192. 33 if (key_size_in_bits != 128 && key_size_in_bits != 256) 34 return NULL; 35 36 size_t key_size_in_bytes = key_size_in_bits / 8; 37 DCHECK_EQ(key_size_in_bits, key_size_in_bytes * 8); 38 39 if (key_size_in_bytes == 0) 40 return NULL; 41 42 OpenSSLErrStackTracer err_tracer(FROM_HERE); 43 scoped_ptr<SymmetricKey> key(new SymmetricKey); 44 uint8_t* key_data = reinterpret_cast<uint8_t*>( 45 base::WriteInto(&key->key_, key_size_in_bytes + 1)); 46 47 int rv = RAND_bytes(key_data, static_cast<int>(key_size_in_bytes)); 48 return rv == 1 ? key.release() : NULL; 49 } 50 51 // static 52 SymmetricKey* SymmetricKey::DeriveKeyFromPassword(Algorithm algorithm, 53 const std::string& password, 54 const std::string& salt, 55 size_t iterations, 56 size_t key_size_in_bits) { 57 DCHECK(algorithm == AES || algorithm == HMAC_SHA1); 58 59 if (algorithm == AES) { 60 // Whitelist supported key sizes to avoid accidentaly relying on 61 // algorithms available in NSS but not BoringSSL and vice 62 // versa. Note that BoringSSL does not support AES-192. 63 if (key_size_in_bits != 128 && key_size_in_bits != 256) 64 return NULL; 65 } 66 67 size_t key_size_in_bytes = key_size_in_bits / 8; 68 DCHECK_EQ(key_size_in_bits, key_size_in_bytes * 8); 69 70 if (key_size_in_bytes == 0) 71 return NULL; 72 73 OpenSSLErrStackTracer err_tracer(FROM_HERE); 74 scoped_ptr<SymmetricKey> key(new SymmetricKey); 75 uint8_t* key_data = reinterpret_cast<uint8_t*>( 76 base::WriteInto(&key->key_, key_size_in_bytes + 1)); 77 int rv = PKCS5_PBKDF2_HMAC_SHA1( 78 password.data(), password.length(), 79 reinterpret_cast<const uint8_t*>(salt.data()), salt.length(), iterations, 80 static_cast<int>(key_size_in_bytes), key_data); 81 return rv == 1 ? key.release() : NULL; 82 } 83 84 // static 85 SymmetricKey* SymmetricKey::Import(Algorithm algorithm, 86 const std::string& raw_key) { 87 if (algorithm == AES) { 88 // Whitelist supported key sizes to avoid accidentaly relying on 89 // algorithms available in NSS but not BoringSSL and vice 90 // versa. Note that BoringSSL does not support AES-192. 91 if (raw_key.size() != 128/8 && raw_key.size() != 256/8) 92 return NULL; 93 } 94 95 scoped_ptr<SymmetricKey> key(new SymmetricKey); 96 key->key_ = raw_key; 97 return key.release(); 98 } 99 100 bool SymmetricKey::GetRawKey(std::string* raw_key) { 101 *raw_key = key_; 102 return true; 103 } 104 105 } // namespace crypto 106
