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 <stdint.h> 18 #include <string.h> 19 #include <sys/types.h> 20 #include <unistd.h> 21 22 #include <keystore/keystore.h> 23 24 /** 25 * When a key is being migrated from a software keymaster implementation 26 * to a hardware keymaster implementation, the first 4 bytes of the key_blob 27 * given to the hardware implementation will be equal to SOFT_KEY_MAGIC. 28 * The hardware implementation should import these PKCS#8 format keys which 29 * are encoded like this: 30 * 31 * 4-byte SOFT_KEY_MAGIC 32 * 33 * 4-byte 32-bit integer big endian for public_key_length. This may be zero 34 * length which indicates the public key should be derived from the 35 * private key. 36 * 37 * public_key_length bytes of public key (may be empty) 38 * 39 * 4-byte 32-bit integer big endian for private_key_length 40 * 41 * private_key_length bytes of private key 42 */ 43 static const uint8_t SOFT_KEY_MAGIC[] = { 'P', 'K', '#', '8' }; 44 45 size_t get_softkey_header_size() { 46 return sizeof(SOFT_KEY_MAGIC); 47 } 48 49 uint8_t* add_softkey_header(uint8_t* key_blob, size_t key_blob_length) { 50 if (key_blob_length < sizeof(SOFT_KEY_MAGIC)) { 51 return NULL; 52 } 53 54 memcpy(key_blob, SOFT_KEY_MAGIC, sizeof(SOFT_KEY_MAGIC)); 55 56 return key_blob + sizeof(SOFT_KEY_MAGIC); 57 } 58 59 bool is_softkey(const uint8_t* key_blob, const size_t key_blob_length) { 60 if (key_blob_length < sizeof(SOFT_KEY_MAGIC)) { 61 return false; 62 } 63 64 return !memcmp(key_blob, SOFT_KEY_MAGIC, sizeof(SOFT_KEY_MAGIC)); 65 } 66
