1 /*
2 * Copyright (C) 2012 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 <sys/types.h>
18 #include <unistd.h>
19
20 /**
21 * When a key is being migrated from a software keymaster implementation
22 * to a hardware keymaster implementation, the first 4 bytes of the key_blob
23 * given to the hardware implementation will be equal to SOFT_KEY_MAGIC.
24 * The hardware implementation should import these PKCS#8 format keys which
25 * are encoded like this:
26 *
27 * 4-byte SOFT_KEY_MAGIC
28 *
29 * 4-byte 32-bit integer big endian for public_key_length
30 *
31 * public_key_length bytes of public key
32 *
33 * 4-byte 32-bit integer big endian for private_key_length
34 *
35 * private_key_length bytes of private key
36 */
37 static const uint8_t SOFT_KEY_MAGIC[] = { 'P', 'K', '#', '8' };
38
get_softkey_header_size()39 size_t get_softkey_header_size() {
40 return sizeof(SOFT_KEY_MAGIC);
41 }
42
add_softkey_header(uint8_t * key_blob,size_t key_blob_length)43 uint8_t* add_softkey_header(uint8_t* key_blob, size_t key_blob_length) {
44 if (key_blob_length < sizeof(SOFT_KEY_MAGIC)) {
45 return NULL;
46 }
47
48 memcpy(key_blob, SOFT_KEY_MAGIC, sizeof(SOFT_KEY_MAGIC));
49
50 return key_blob + sizeof(SOFT_KEY_MAGIC);
51 }
52
is_softkey(const uint8_t * key_blob,const size_t key_blob_length)53 bool is_softkey(const uint8_t* key_blob, const size_t key_blob_length) {
54 if (key_blob_length < sizeof(SOFT_KEY_MAGIC)) {
55 return false;
56 }
57
58 return !memcmp(key_blob, SOFT_KEY_MAGIC, sizeof(SOFT_KEY_MAGIC));
59 }
60