1 /*
2 * Copyright 2020 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 <crypto_utils/android_pubkey.h>
18 #include <fuzzer/FuzzedDataProvider.h>
19 #include <string.h>
20 #include <memory>
21 #include <openssl/obj_mac.h>
22 #include <openssl/rsa.h>
23 #include <cstdio>
24 #include <limits>
25
26 #define ANDROID_PUBKEY_MODULUS_SIZE_WORDS (ANDROID_PUBKEY_MODULUS_SIZE / 4)
27
LLVMFuzzerTestOneInput(const uint8_t * data,std::size_t size)28 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, std::size_t size) {
29 if (size < 2050) {
30 return 0;
31 }
32
33 FuzzedDataProvider fdp(data, size);
34
35 uint8_t buffer[ANDROID_PUBKEY_ENCODED_SIZE];
36 uint32_t modulus_size_words = ANDROID_PUBKEY_MODULUS_SIZE_WORDS;
37 memcpy(buffer, &modulus_size_words, sizeof(uint32_t));
38
39 uint32_t n0inv = fdp.ConsumeIntegralInRange<uint32_t>(0,std::numeric_limits<uint32_t>::max());
40 memcpy(buffer+sizeof(uint32_t), &n0inv, sizeof(uint32_t));
41
42 std::string s = fdp.ConsumeBytesAsString(ANDROID_PUBKEY_MODULUS_SIZE);
43 uint8_t* modulus = (uint8_t*)s.c_str();
44 memcpy(buffer+sizeof(uint32_t)*2, modulus,
45 sizeof(uint8_t)*ANDROID_PUBKEY_MODULUS_SIZE);
46
47 std::string ss = fdp.ConsumeBytesAsString(ANDROID_PUBKEY_MODULUS_SIZE);
48 uint8_t* rr = (uint8_t*)ss.c_str();
49 memcpy(buffer+sizeof(uint32_t)*2+ANDROID_PUBKEY_MODULUS_SIZE, rr,
50 sizeof(uint8_t)*ANDROID_PUBKEY_MODULUS_SIZE);
51
52 int flip = fdp.ConsumeIntegralInRange<uint32_t>(0,1);
53 buffer[ANDROID_PUBKEY_ENCODED_SIZE-1] = (uint8_t)(flip == 0 ? 3 : 65537);
54
55 RSA* new_key = nullptr;
56 android_pubkey_decode(buffer, sizeof(uint8_t)*ANDROID_PUBKEY_ENCODED_SIZE, &new_key);
57
58 uint8_t key_data[ANDROID_PUBKEY_ENCODED_SIZE];
59 android_pubkey_encode(new_key, key_data, sizeof(key_data));
60
61 assert(0 == memcmp(buffer, key_data, sizeof(buffer)));
62
63 RSA_free(new_key);
64
65 return 0;
66 }
67