1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "crypto/signature_creator.h"
6
7#include <openssl/evp.h>
8#include <openssl/rsa.h>
9#include <stddef.h>
10#include <stdint.h>
11
12#include "base/logging.h"
13#include "base/memory/scoped_ptr.h"
14#include "crypto/openssl_util.h"
15#include "crypto/rsa_private_key.h"
16#include "crypto/scoped_openssl_types.h"
17
18namespace crypto {
19
20namespace {
21
22const EVP_MD* ToOpenSSLDigest(SignatureCreator::HashAlgorithm hash_alg) {
23  switch (hash_alg) {
24    case SignatureCreator::SHA1:
25      return EVP_sha1();
26    case SignatureCreator::SHA256:
27      return EVP_sha256();
28  }
29  return NULL;
30}
31
32int ToOpenSSLDigestType(SignatureCreator::HashAlgorithm hash_alg) {
33  switch (hash_alg) {
34    case SignatureCreator::SHA1:
35      return NID_sha1;
36    case SignatureCreator::SHA256:
37      return NID_sha256;
38  }
39  return NID_undef;
40}
41
42}  // namespace
43
44// static
45SignatureCreator* SignatureCreator::Create(RSAPrivateKey* key,
46                                           HashAlgorithm hash_alg) {
47  OpenSSLErrStackTracer err_tracer(FROM_HERE);
48  scoped_ptr<SignatureCreator> result(new SignatureCreator);
49  const EVP_MD* const digest = ToOpenSSLDigest(hash_alg);
50  DCHECK(digest);
51  if (!digest) {
52    return NULL;
53  }
54  if (!EVP_DigestSignInit(result->sign_context_, NULL, digest, NULL,
55                          key->key())) {
56    return NULL;
57  }
58  return result.release();
59}
60
61// static
62bool SignatureCreator::Sign(RSAPrivateKey* key,
63                            HashAlgorithm hash_alg,
64                            const uint8_t* data,
65                            int data_len,
66                            std::vector<uint8_t>* signature) {
67  ScopedRSA rsa_key(EVP_PKEY_get1_RSA(key->key()));
68  if (!rsa_key)
69    return false;
70  signature->resize(RSA_size(rsa_key.get()));
71
72  unsigned int len = 0;
73  if (!RSA_sign(ToOpenSSLDigestType(hash_alg), data, data_len,
74                signature->data(), &len, rsa_key.get())) {
75    signature->clear();
76    return false;
77  }
78  signature->resize(len);
79  return true;
80}
81
82SignatureCreator::SignatureCreator()
83    : sign_context_(EVP_MD_CTX_create()) {
84}
85
86SignatureCreator::~SignatureCreator() {
87  EVP_MD_CTX_destroy(sign_context_);
88}
89
90bool SignatureCreator::Update(const uint8_t* data_part, int data_part_len) {
91  OpenSSLErrStackTracer err_tracer(FROM_HERE);
92  return !!EVP_DigestSignUpdate(sign_context_, data_part, data_part_len);
93}
94
95bool SignatureCreator::Final(std::vector<uint8_t>* signature) {
96  OpenSSLErrStackTracer err_tracer(FROM_HERE);
97
98  // Determine the maximum length of the signature.
99  size_t len = 0;
100  if (!EVP_DigestSignFinal(sign_context_, NULL, &len)) {
101    signature->clear();
102    return false;
103  }
104  signature->resize(len);
105
106  // Sign it.
107  if (!EVP_DigestSignFinal(sign_context_, signature->data(), &len)) {
108    signature->clear();
109    return false;
110  }
111  signature->resize(len);
112  return true;
113}
114
115}  // namespace crypto
116