Quan Nguyen | f7538e0 | 2015-05-21 00:49:11 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2015 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
Janis Danisevskis | f54cc93 | 2017-05-10 15:29:10 -0700 | [diff] [blame] | 17 | #include <keymaster/km_openssl/iso18033kdf.h> |
Quan Nguyen | f7538e0 | 2015-05-21 00:49:11 -0700 | [diff] [blame] | 18 | |
Quan Nguyen | f7538e0 | 2015-05-21 00:49:11 -0700 | [diff] [blame] | 19 | #include <openssl/evp.h> |
| 20 | |
Janis Danisevskis | f54cc93 | 2017-05-10 15:29:10 -0700 | [diff] [blame] | 21 | #include <keymaster/km_openssl/openssl_utils.h> |
| 22 | |
Quan Nguyen | f7538e0 | 2015-05-21 00:49:11 -0700 | [diff] [blame] | 23 | namespace keymaster { |
| 24 | |
| 25 | inline size_t min(size_t a, size_t b) { |
| 26 | return (a < b) ? a : b; |
| 27 | } |
| 28 | |
| 29 | bool Iso18033Kdf::GenerateKey(const uint8_t* info, size_t info_len, uint8_t* output, |
| 30 | size_t output_len) { |
Shawn Willden | fb9b2a4 | 2017-12-21 12:35:06 -0700 | [diff] [blame] | 31 | if (!is_initialized_ || output == nullptr) return false; |
Quan Nguyen | f7538e0 | 2015-05-21 00:49:11 -0700 | [diff] [blame] | 32 | |
| 33 | /* Check whether output length is too long as specified in ISO/IEC 18033-2. */ |
Shawn Willden | fb9b2a4 | 2017-12-21 12:35:06 -0700 | [diff] [blame] | 34 | if ((0xFFFFFFFFULL + start_counter_) * digest_size_ < (uint64_t)output_len) return false; |
Quan Nguyen | f7538e0 | 2015-05-21 00:49:11 -0700 | [diff] [blame] | 35 | |
| 36 | EVP_MD_CTX ctx; |
| 37 | EvpMdCtxCleaner ctxCleaner(&ctx); |
| 38 | EVP_MD_CTX_init(&ctx); |
| 39 | |
| 40 | size_t num_blocks = (output_len + digest_size_ - 1) / digest_size_; |
Shawn Willden | fb9b2a4 | 2017-12-21 12:35:06 -0700 | [diff] [blame] | 41 | UniquePtr<uint8_t[]> counter(new (std::nothrow) uint8_t[4]); |
| 42 | UniquePtr<uint8_t[]> digest_result(new (std::nothrow) uint8_t[digest_size_]); |
| 43 | if (!counter.get() || !digest_result.get()) return false; |
Quan Nguyen | f7538e0 | 2015-05-21 00:49:11 -0700 | [diff] [blame] | 44 | for (size_t block = 0; block < num_blocks; block++) { |
| 45 | switch (digest_type_) { |
| 46 | case KM_DIGEST_SHA1: |
Shawn Willden | fb9b2a4 | 2017-12-21 12:35:06 -0700 | [diff] [blame] | 47 | if (!EVP_DigestInit_ex(&ctx, EVP_sha1(), nullptr /* default digest */)) return false; |
Quan Nguyen | f7538e0 | 2015-05-21 00:49:11 -0700 | [diff] [blame] | 48 | break; |
| 49 | case KM_DIGEST_SHA_2_256: |
Shawn Willden | fb9b2a4 | 2017-12-21 12:35:06 -0700 | [diff] [blame] | 50 | if (!EVP_DigestInit_ex(&ctx, EVP_sha256(), nullptr /* default digest */)) return false; |
Quan Nguyen | f7538e0 | 2015-05-21 00:49:11 -0700 | [diff] [blame] | 51 | break; |
| 52 | default: |
| 53 | return false; |
| 54 | } |
| 55 | |
| 56 | if (!EVP_DigestUpdate(&ctx, secret_key_.get(), secret_key_len_) || |
| 57 | !Uint32ToBigEndianByteArray(block + start_counter_, counter.get()) || |
| 58 | !EVP_DigestUpdate(&ctx, counter.get(), 4)) |
| 59 | return false; |
| 60 | |
| 61 | if (info != nullptr && info_len > 0) { |
Shawn Willden | fb9b2a4 | 2017-12-21 12:35:06 -0700 | [diff] [blame] | 62 | if (!EVP_DigestUpdate(&ctx, info, info_len)) return false; |
Quan Nguyen | f7538e0 | 2015-05-21 00:49:11 -0700 | [diff] [blame] | 63 | } |
| 64 | |
| 65 | /* OpenSSL does not accept size_t parameter. */ |
| 66 | uint32_t uint32_digest_size_ = digest_size_; |
| 67 | if (!EVP_DigestFinal_ex(&ctx, digest_result.get(), &uint32_digest_size_) || |
| 68 | uint32_digest_size_ != digest_size_) |
| 69 | return false; |
| 70 | |
| 71 | size_t block_start = digest_size_ * block; |
| 72 | size_t block_length = min(digest_size_, output_len - block_start); |
| 73 | memcpy(output + block_start, digest_result.get(), block_length); |
| 74 | } |
| 75 | return true; |
| 76 | } |
| 77 | |
| 78 | } // namespace keymaster |