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 = 43 reinterpret_cast<uint8*>(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 = 74 reinterpret_cast<uint8*>(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 105
