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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdint.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include <keystore/keystore.h>
/**
* When a key is being migrated from a software keymaster implementation
* to a hardware keymaster implementation, the first 4 bytes of the key_blob
* given to the hardware implementation will be equal to SOFT_KEY_MAGIC.
* The hardware implementation should import these PKCS#8 format keys which
* are encoded like this:
*
* 4-byte SOFT_KEY_MAGIC
*
* 4-byte 32-bit integer big endian for public_key_length. This may be zero
* length which indicates the public key should be derived from the
* private key.
*
* public_key_length bytes of public key (may be empty)
*
* 4-byte 32-bit integer big endian for private_key_length
*
* private_key_length bytes of private key
*/
static const uint8_t SOFT_KEY_MAGIC[] = { 'P', 'K', '#', '8' };
size_t get_softkey_header_size() {
return sizeof(SOFT_KEY_MAGIC);
}
uint8_t* add_softkey_header(uint8_t* key_blob, size_t key_blob_length) {
if (key_blob_length < sizeof(SOFT_KEY_MAGIC)) {
return NULL;
}
memcpy(key_blob, SOFT_KEY_MAGIC, sizeof(SOFT_KEY_MAGIC));
return key_blob + sizeof(SOFT_KEY_MAGIC);
}
bool is_softkey(const uint8_t* key_blob, const size_t key_blob_length) {
if (key_blob_length < sizeof(SOFT_KEY_MAGIC)) {
return false;
}
return !memcmp(key_blob, SOFT_KEY_MAGIC, sizeof(SOFT_KEY_MAGIC));
}
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