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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 "2sysincludes.h"
#include "2common.h"
#include "2sha.h"
#include "cryptolib.h"
#include "host_common.h"
#include "signature_digest.h"
uint8_t* PrependDigestInfo(unsigned int algorithm, uint8_t* digest) {
const int digest_size = vb2_digest_size(vb2_crypto_to_hash(algorithm));
const int digestinfo_size = digestinfo_size_map[algorithm];
const uint8_t* digestinfo = hash_digestinfo_map[algorithm];
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 */
if (algorithm >= kNumAlgorithms) {
VBDEBUG(("SignatureDigest() called with invalid algorithm!\n"));
} else if (VB2_SUCCESS == vb2_digest_buffer(buf, len,
vb2_crypto_to_hash(algorithm),
digest, sizeof(digest))) {
info_digest = PrependDigestInfo(algorithm, digest);
}
return info_digest;
}
uint8_t* SignatureBuf(const uint8_t* buf, uint64_t len, const char* key_file,
unsigned int algorithm) {
FILE* key_fp = NULL;
RSA* key = NULL;
uint8_t* signature = NULL;
uint8_t* signature_digest = SignatureDigest(buf, len, algorithm);
const int digest_size = vb2_digest_size(vb2_crypto_to_hash(algorithm));
int signature_digest_len = (digest_size + digestinfo_size_map[algorithm]);
key_fp = fopen(key_file, "r");
if (!key_fp) {
VBDEBUG(("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(siglen_map[algorithm]);
else
VBDEBUG(("SignatureBuf(): Couldn't read private key from file: %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. */
VBDEBUG(("SignatureBuf(): RSA_private_encrypt() failed.\n"));
}
fclose(key_fp);
if (key)
RSA_free(key);
free(signature_digest);
return signature;
}
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