1 /*
2  * Copyright (C) 2019 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 
17 #include "adb/crypto/rsa_2048_key.h"
18 
19 #include <android-base/logging.h>
20 #include <crypto_utils/android_pubkey.h>
21 #include <openssl/bn.h>
22 #include <openssl/rsa.h>
23 #include <sysdeps/env.h>
24 
25 namespace adb {
26 namespace crypto {
27 
28 bool CalculatePublicKey(std::string* out, RSA* private_key) {
29     uint8_t binary_key_data[ANDROID_PUBKEY_ENCODED_SIZE];
30     if (!android_pubkey_encode(private_key, binary_key_data, sizeof(binary_key_data))) {
31         LOG(ERROR) << "Failed to convert to public key";
32         return false;
33     }
34 
35     size_t expected_length;
36     if (!EVP_EncodedLength(&expected_length, sizeof(binary_key_data))) {
37         LOG(ERROR) << "Public key too large to base64 encode";
38         return false;
39     }
40 
41     out->resize(expected_length);
42     size_t actual_length = EVP_EncodeBlock(reinterpret_cast<uint8_t*>(out->data()), binary_key_data,
43                                            sizeof(binary_key_data));
44     out->resize(actual_length);
45     out->append(" ");
46     out->append(sysdeps::GetLoginNameUTF8());
47     out->append("@");
48     out->append(sysdeps::GetHostNameUTF8());
49     return true;
50 }
51 
52 std::optional<Key> CreateRSA2048Key() {
53     bssl::UniquePtr<EVP_PKEY> pkey(EVP_PKEY_new());
54     bssl::UniquePtr<BIGNUM> exponent(BN_new());
55     bssl::UniquePtr<RSA> rsa(RSA_new());
56     if (!pkey || !exponent || !rsa) {
57         LOG(ERROR) << "Failed to allocate key";
58         return std::nullopt;
59     }
60 
61     BN_set_word(exponent.get(), RSA_F4);
62     RSA_generate_key_ex(rsa.get(), 2048, exponent.get(), nullptr);
63     EVP_PKEY_set1_RSA(pkey.get(), rsa.get());
64 
65     return std::optional<Key>{Key(std::move(pkey), adb::proto::KeyType::RSA_2048)};
66 }
67 
68 }  // namespace crypto
69 }  // namespace adb
70