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/* Copyright (c) 2010 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.
*/
#include <openssl/pem.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "2common.h"
#include "2rsa.h"
#include "2sha.h"
#include "2sysincludes.h"
#include "host_common.h"
#include "host_signature2.h"
#include "signature_digest.h"
uint8_t* PrependDigestInfo(enum vb2_hash_algorithm hash_alg, uint8_t* digest)
{
const int digest_size = vb2_digest_size(hash_alg);
uint32_t digestinfo_size = 0;
const uint8_t* digestinfo = NULL;
if (VB2_SUCCESS != vb2_digest_info(hash_alg, &digestinfo,
&digestinfo_size))
return NULL;
uint8_t* p = malloc(digestinfo_size + digest_size);
memcpy(p, digestinfo, digestinfo_size);
memcpy(p + digestinfo_size, digest, digest_size);
return p;
}
uint8_t* SignatureDigest(const uint8_t* buf, uint64_t len,
unsigned int algorithm)
{
uint8_t* info_digest = NULL;
uint8_t digest[VB2_SHA512_DIGEST_SIZE]; /* Longest digest */
enum vb2_hash_algorithm hash_alg;
if (algorithm >= VB2_ALG_COUNT) {
fprintf(stderr,
"SignatureDigest(): Called with invalid algorithm!\n");
return NULL;
}
hash_alg = vb2_crypto_to_hash(algorithm);
if (VB2_SUCCESS == vb2_digest_buffer(buf, len, hash_alg,
digest, sizeof(digest))) {
info_digest = PrependDigestInfo(hash_alg, digest);
}
return info_digest;
}
uint8_t* SignatureBuf(const uint8_t* buf, uint64_t len, const char* key_file,
unsigned int algorithm)
{
const enum vb2_hash_algorithm hash_alg = vb2_crypto_to_hash(algorithm);
FILE* key_fp = NULL;
RSA* key = NULL;
uint8_t* signature = NULL;
uint8_t* signature_digest = SignatureDigest(buf, len, algorithm);
if (!signature_digest) {
fprintf(stderr, "SignatureBuf(): "
"Couldn't get signature digest\n");
return NULL;
}
const int digest_size = vb2_digest_size(hash_alg);
uint32_t digestinfo_size = 0;
const uint8_t* digestinfo = NULL;
if (VB2_SUCCESS != vb2_digest_info(hash_alg, &digestinfo,
&digestinfo_size)) {
fprintf(stderr, "SignatureBuf(): Couldn't get digest info\n");
free(signature_digest);
return NULL;
}
int signature_digest_len = digest_size + digestinfo_size;
key_fp = fopen(key_file, "r");
if (!key_fp) {
fprintf(stderr, "SignatureBuf(): Couldn't open key file: %s\n",
key_file);
free(signature_digest);
return NULL;
}
if ((key = PEM_read_RSAPrivateKey(key_fp, NULL, NULL, NULL)))
signature = (uint8_t *)malloc(
vb2_rsa_sig_size(vb2_crypto_to_signature(algorithm)));
else
fprintf(stderr, "SignatureBuf(): "
"Couldn't read private key from: %s\n", key_file);
if (signature) {
if (-1 == RSA_private_encrypt(
signature_digest_len, /* Input length. */
signature_digest, /* Input data. */
signature, /* Output signature. */
key, /* Key to use. */
RSA_PKCS1_PADDING)) /* Padding to use. */
fprintf(stderr, "SignatureBuf(): "
"RSA_private_encrypt() failed.\n");
}
fclose(key_fp);
if (key)
RSA_free(key);
free(signature_digest);
return signature;
}
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