1/*
2 *  Copyright 2011 The WebRTC Project Authors. All rights reserved.
3 *
4 *  Use of this source code is governed by a BSD-style license
5 *  that can be found in the LICENSE file in the root of the source
6 *  tree. An additional intellectual property rights grant can be found
7 *  in the file PATENTS.  All contributing project authors may
8 *  be found in the AUTHORS file in the root of the source tree.
9 */
10
11#include "webrtc/base/messagedigest.h"
12
13#include <string.h>
14
15#include "webrtc/base/basictypes.h"
16#include "webrtc/base/sslconfig.h"
17#if SSL_USE_OPENSSL
18#include "webrtc/base/openssldigest.h"
19#else
20#include "webrtc/base/md5digest.h"
21#include "webrtc/base/sha1digest.h"
22#endif
23#include "webrtc/base/scoped_ptr.h"
24#include "webrtc/base/stringencode.h"
25
26namespace rtc {
27
28// From RFC 4572.
29const char DIGEST_MD5[]     = "md5";
30const char DIGEST_SHA_1[]   = "sha-1";
31const char DIGEST_SHA_224[] = "sha-224";
32const char DIGEST_SHA_256[] = "sha-256";
33const char DIGEST_SHA_384[] = "sha-384";
34const char DIGEST_SHA_512[] = "sha-512";
35
36static const size_t kBlockSize = 64;  // valid for SHA-256 and down
37
38MessageDigest* MessageDigestFactory::Create(const std::string& alg) {
39#if SSL_USE_OPENSSL
40  MessageDigest* digest = new OpenSSLDigest(alg);
41  if (digest->Size() == 0) {  // invalid algorithm
42    delete digest;
43    digest = NULL;
44  }
45  return digest;
46#else
47  MessageDigest* digest = NULL;
48  if (alg == DIGEST_MD5) {
49    digest = new Md5Digest();
50  } else if (alg == DIGEST_SHA_1) {
51    digest = new Sha1Digest();
52  }
53  return digest;
54#endif
55}
56
57bool IsFips180DigestAlgorithm(const std::string& alg) {
58  // These are the FIPS 180 algorithms.  According to RFC 4572 Section 5,
59  // "Self-signed certificates (for which legacy certificates are not a
60  // consideration) MUST use one of the FIPS 180 algorithms (SHA-1,
61  // SHA-224, SHA-256, SHA-384, or SHA-512) as their signature algorithm,
62  // and thus also MUST use it to calculate certificate fingerprints."
63  return alg == DIGEST_SHA_1 ||
64         alg == DIGEST_SHA_224 ||
65         alg == DIGEST_SHA_256 ||
66         alg == DIGEST_SHA_384 ||
67         alg == DIGEST_SHA_512;
68}
69
70size_t ComputeDigest(MessageDigest* digest, const void* input, size_t in_len,
71                     void* output, size_t out_len) {
72  digest->Update(input, in_len);
73  return digest->Finish(output, out_len);
74}
75
76size_t ComputeDigest(const std::string& alg, const void* input, size_t in_len,
77                     void* output, size_t out_len) {
78  scoped_ptr<MessageDigest> digest(MessageDigestFactory::Create(alg));
79  return (digest) ?
80      ComputeDigest(digest.get(), input, in_len, output, out_len) :
81      0;
82}
83
84std::string ComputeDigest(MessageDigest* digest, const std::string& input) {
85  scoped_ptr<char[]> output(new char[digest->Size()]);
86  ComputeDigest(digest, input.data(), input.size(),
87                output.get(), digest->Size());
88  return hex_encode(output.get(), digest->Size());
89}
90
91bool ComputeDigest(const std::string& alg, const std::string& input,
92                   std::string* output) {
93  scoped_ptr<MessageDigest> digest(MessageDigestFactory::Create(alg));
94  if (!digest) {
95    return false;
96  }
97  *output = ComputeDigest(digest.get(), input);
98  return true;
99}
100
101std::string ComputeDigest(const std::string& alg, const std::string& input) {
102  std::string output;
103  ComputeDigest(alg, input, &output);
104  return output;
105}
106
107// Compute a RFC 2104 HMAC: H(K XOR opad, H(K XOR ipad, text))
108size_t ComputeHmac(MessageDigest* digest,
109                   const void* key, size_t key_len,
110                   const void* input, size_t in_len,
111                   void* output, size_t out_len) {
112  // We only handle algorithms with a 64-byte blocksize.
113  // TODO: Add BlockSize() method to MessageDigest.
114  size_t block_len = kBlockSize;
115  if (digest->Size() > 32) {
116    return 0;
117  }
118  // Copy the key to a block-sized buffer to simplify padding.
119  // If the key is longer than a block, hash it and use the result instead.
120  scoped_ptr<uint8_t[]> new_key(new uint8_t[block_len]);
121  if (key_len > block_len) {
122    ComputeDigest(digest, key, key_len, new_key.get(), block_len);
123    memset(new_key.get() + digest->Size(), 0, block_len - digest->Size());
124  } else {
125    memcpy(new_key.get(), key, key_len);
126    memset(new_key.get() + key_len, 0, block_len - key_len);
127  }
128  // Set up the padding from the key, salting appropriately for each padding.
129  scoped_ptr<uint8_t[]> o_pad(new uint8_t[block_len]);
130  scoped_ptr<uint8_t[]> i_pad(new uint8_t[block_len]);
131  for (size_t i = 0; i < block_len; ++i) {
132    o_pad[i] = 0x5c ^ new_key[i];
133    i_pad[i] = 0x36 ^ new_key[i];
134  }
135  // Inner hash; hash the inner padding, and then the input buffer.
136  scoped_ptr<uint8_t[]> inner(new uint8_t[digest->Size()]);
137  digest->Update(i_pad.get(), block_len);
138  digest->Update(input, in_len);
139  digest->Finish(inner.get(), digest->Size());
140  // Outer hash; hash the outer padding, and then the result of the inner hash.
141  digest->Update(o_pad.get(), block_len);
142  digest->Update(inner.get(), digest->Size());
143  return digest->Finish(output, out_len);
144}
145
146size_t ComputeHmac(const std::string& alg, const void* key, size_t key_len,
147                   const void* input, size_t in_len,
148                   void* output, size_t out_len) {
149  scoped_ptr<MessageDigest> digest(MessageDigestFactory::Create(alg));
150  if (!digest) {
151    return 0;
152  }
153  return ComputeHmac(digest.get(), key, key_len,
154                     input, in_len, output, out_len);
155}
156
157std::string ComputeHmac(MessageDigest* digest, const std::string& key,
158                        const std::string& input) {
159  scoped_ptr<char[]> output(new char[digest->Size()]);
160  ComputeHmac(digest, key.data(), key.size(),
161              input.data(), input.size(), output.get(), digest->Size());
162  return hex_encode(output.get(), digest->Size());
163}
164
165bool ComputeHmac(const std::string& alg, const std::string& key,
166                 const std::string& input, std::string* output) {
167  scoped_ptr<MessageDigest> digest(MessageDigestFactory::Create(alg));
168  if (!digest) {
169    return false;
170  }
171  *output = ComputeHmac(digest.get(), key, input);
172  return true;
173}
174
175std::string ComputeHmac(const std::string& alg, const std::string& key,
176                        const std::string& input) {
177  std::string output;
178  ComputeHmac(alg, key, input, &output);
179  return output;
180}
181
182}  // namespace rtc
183