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/* Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*
* Host functions for verified boot.
*/
#include "2sysincludes.h"
#include "2common.h"
#include "2sha.h"
#include "cryptolib.h"
#include "host_common.h"
#include "host_keyblock.h"
#include "vboot_common.h"
VbKeyBlockHeader* KeyBlockCreate(const VbPublicKey* data_key,
const VbPrivateKey* signing_key,
uint64_t flags) {
VbKeyBlockHeader* h;
uint64_t signed_size = sizeof(VbKeyBlockHeader) + data_key->key_size;
uint64_t block_size = (signed_size + VB2_SHA512_DIGEST_SIZE +
(signing_key ?
siglen_map[signing_key->algorithm] : 0));
uint8_t* data_key_dest;
uint8_t* block_sig_dest;
uint8_t* block_chk_dest;
VbSignature *sigtmp;
/* Allocate key block */
h = (VbKeyBlockHeader*)malloc(block_size);
if (!h)
return NULL;
data_key_dest = (uint8_t*)(h + 1);
block_chk_dest = data_key_dest + data_key->key_size;
block_sig_dest = block_chk_dest + VB2_SHA512_DIGEST_SIZE;
Memcpy(h->magic, KEY_BLOCK_MAGIC, KEY_BLOCK_MAGIC_SIZE);
h->header_version_major = KEY_BLOCK_HEADER_VERSION_MAJOR;
h->header_version_minor = KEY_BLOCK_HEADER_VERSION_MINOR;
h->key_block_size = block_size;
h->key_block_flags = flags;
/* Copy data key */
PublicKeyInit(&h->data_key, data_key_dest, data_key->key_size);
PublicKeyCopy(&h->data_key, data_key);
/* Set up signature structs so we can calculate the signatures */
SignatureInit(&h->key_block_checksum, block_chk_dest,
VB2_SHA512_DIGEST_SIZE, signed_size);
if (signing_key)
SignatureInit(&h->key_block_signature, block_sig_dest,
siglen_map[signing_key->algorithm], signed_size);
else
Memset(&h->key_block_signature, 0, sizeof(VbSignature));
/* Calculate checksum */
struct vb2_signature *chk = vb2_sha512_signature((uint8_t*)h, signed_size);
SignatureCopy(&h->key_block_checksum, (VbSignature *)chk);
free(chk);
/* Calculate signature */
if (signing_key) {
sigtmp = CalculateSignature((uint8_t*)h, signed_size, signing_key);
SignatureCopy(&h->key_block_signature, sigtmp);
free(sigtmp);
}
/* Return the header */
return h;
}
/* TODO(gauravsh): This could easily be integrated into KeyBlockCreate()
* since the code is almost a mirror - I have kept it as such to avoid changing
* the existing interface. */
VbKeyBlockHeader* KeyBlockCreate_external(const VbPublicKey* data_key,
const char* signing_key_pem_file,
uint64_t algorithm,
uint64_t flags,
const char* external_signer) {
VbKeyBlockHeader* h;
uint64_t signed_size = sizeof(VbKeyBlockHeader) + data_key->key_size;
uint64_t block_size = (signed_size + VB2_SHA512_DIGEST_SIZE +
siglen_map[algorithm]);
uint8_t* data_key_dest;
uint8_t* block_sig_dest;
uint8_t* block_chk_dest;
VbSignature *sigtmp;
/* Allocate key block */
h = (VbKeyBlockHeader*)malloc(block_size);
if (!h)
return NULL;
if (!signing_key_pem_file || !data_key || !external_signer)
return NULL;
data_key_dest = (uint8_t*)(h + 1);
block_chk_dest = data_key_dest + data_key->key_size;
block_sig_dest = block_chk_dest + VB2_SHA512_DIGEST_SIZE;
Memcpy(h->magic, KEY_BLOCK_MAGIC, KEY_BLOCK_MAGIC_SIZE);
h->header_version_major = KEY_BLOCK_HEADER_VERSION_MAJOR;
h->header_version_minor = KEY_BLOCK_HEADER_VERSION_MINOR;
h->key_block_size = block_size;
h->key_block_flags = flags;
/* Copy data key */
PublicKeyInit(&h->data_key, data_key_dest, data_key->key_size);
PublicKeyCopy(&h->data_key, data_key);
/* Set up signature structs so we can calculate the signatures */
SignatureInit(&h->key_block_checksum, block_chk_dest,
VB2_SHA512_DIGEST_SIZE, signed_size);
SignatureInit(&h->key_block_signature, block_sig_dest,
siglen_map[algorithm], signed_size);
/* Calculate checksum */
struct vb2_signature *chk = vb2_sha512_signature((uint8_t*)h, signed_size);
SignatureCopy(&h->key_block_checksum, (VbSignature *)chk);
free(chk);
/* Calculate signature */
sigtmp = CalculateSignature_external((uint8_t*)h, signed_size,
signing_key_pem_file, algorithm,
external_signer);
SignatureCopy(&h->key_block_signature, sigtmp);
free(sigtmp);
/* Return the header */
return h;
}
/* Read a key block from a .keyblock file. Caller owns the returned
* pointer, and must free it with free().
*
* Returns NULL if error. */
VbKeyBlockHeader* KeyBlockRead(const char* filename) {
VbKeyBlockHeader* block;
uint64_t file_size;
block = (VbKeyBlockHeader*)ReadFile(filename, &file_size);
if (!block) {
VBDEBUG(("Error reading key block file: %s\n", filename));
return NULL;
}
/* Verify the hash of the key block, since we can do that without
* the public signing key. */
if (0 != KeyBlockVerify(block, file_size, NULL, 1)) {
VBDEBUG(("Invalid key block file: %s\n", filename));
free(block);
return NULL;
}
return block;
}
/* Write a key block to a file in .keyblock format. */
int KeyBlockWrite(const char* filename, const VbKeyBlockHeader* key_block) {
if (0 != WriteFile(filename, key_block, key_block->key_block_size)) {
VBDEBUG(("KeyBlockWrite() error writing key block\n"));
return 1;
}
return 0;
}
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