1// Copyright (c) 2011 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// The original file was copied from sqlite, and was in the public domain.
6
7/*
8 * This code implements the MD5 message-digest algorithm.
9 * The algorithm is due to Ron Rivest.  This code was
10 * written by Colin Plumb in 1993, no copyright is claimed.
11 * This code is in the public domain; do with it what you wish.
12 *
13 * Equivalent code is available from RSA Data Security, Inc.
14 * This code has been tested against that, and is equivalent,
15 * except that you don't need to include two pages of legalese
16 * with every copy.
17 *
18 * To compute the message digest of a chunk of bytes, declare an
19 * MD5Context structure, pass it to MD5Init, call MD5Update as
20 * needed on buffers full of bytes, and then call MD5Final, which
21 * will fill a supplied 16-byte array with the digest.
22 */
23
24#include "base/md5.h"
25
26#include <stddef.h>
27
28namespace {
29
30struct Context {
31  uint32_t buf[4];
32  uint32_t bits[2];
33  uint8_t in[64];
34};
35
36/*
37 * Note: this code is harmless on little-endian machines.
38 */
39void byteReverse(uint8_t* buf, unsigned longs) {
40  do {
41    uint32_t temp = static_cast<uint32_t>(
42        static_cast<unsigned>(buf[3]) << 8 |
43        buf[2]) << 16 |
44        (static_cast<unsigned>(buf[1]) << 8 | buf[0]);
45    *reinterpret_cast<uint32_t*>(buf) = temp;
46    buf += 4;
47  } while (--longs);
48}
49
50/* The four core functions - F1 is optimized somewhat */
51
52/* #define F1(x, y, z) (x & y | ~x & z) */
53#define F1(x, y, z) (z ^ (x & (y ^ z)))
54#define F2(x, y, z) F1(z, x, y)
55#define F3(x, y, z) (x ^ y ^ z)
56#define F4(x, y, z) (y ^ (x | ~z))
57
58/* This is the central step in the MD5 algorithm. */
59#define MD5STEP(f, w, x, y, z, data, s) \
60  (w += f(x, y, z) + data, w = w << s | w >> (32 - s), w += x)
61
62/*
63 * The core of the MD5 algorithm, this alters an existing MD5 hash to
64 * reflect the addition of 16 longwords of new data.  MD5Update blocks
65 * the data and converts bytes into longwords for this routine.
66 */
67void MD5Transform(uint32_t buf[4], const uint32_t in[16]) {
68  uint32_t a, b, c, d;
69
70  a = buf[0];
71  b = buf[1];
72  c = buf[2];
73  d = buf[3];
74
75  MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
76  MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
77  MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
78  MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
79  MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
80  MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
81  MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
82  MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
83  MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
84  MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
85  MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
86  MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
87  MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
88  MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
89  MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
90  MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
91
92  MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
93  MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
94  MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
95  MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
96  MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
97  MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
98  MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
99  MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
100  MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
101  MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
102  MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
103  MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
104  MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
105  MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
106  MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
107  MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
108
109  MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
110  MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
111  MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
112  MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
113  MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
114  MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
115  MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
116  MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
117  MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
118  MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
119  MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
120  MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
121  MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
122  MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
123  MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
124  MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
125
126  MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
127  MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
128  MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
129  MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
130  MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
131  MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
132  MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
133  MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
134  MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
135  MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
136  MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
137  MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
138  MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
139  MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
140  MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
141  MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
142
143  buf[0] += a;
144  buf[1] += b;
145  buf[2] += c;
146  buf[3] += d;
147}
148
149}  // namespace
150
151namespace base {
152
153/*
154 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
155 * initialization constants.
156 */
157void MD5Init(MD5Context* context) {
158  struct Context* ctx = reinterpret_cast<struct Context*>(context);
159  ctx->buf[0] = 0x67452301;
160  ctx->buf[1] = 0xefcdab89;
161  ctx->buf[2] = 0x98badcfe;
162  ctx->buf[3] = 0x10325476;
163  ctx->bits[0] = 0;
164  ctx->bits[1] = 0;
165}
166
167/*
168 * Update context to reflect the concatenation of another buffer full
169 * of bytes.
170 */
171void MD5Update(MD5Context* context, const StringPiece& data) {
172  struct Context* ctx = reinterpret_cast<struct Context*>(context);
173  const uint8_t* buf = reinterpret_cast<const uint8_t*>(data.data());
174  size_t len = data.size();
175
176  /* Update bitcount */
177
178  uint32_t t = ctx->bits[0];
179  if ((ctx->bits[0] = t + (static_cast<uint32_t>(len) << 3)) < t)
180    ctx->bits[1]++; /* Carry from low to high */
181  ctx->bits[1] += static_cast<uint32_t>(len >> 29);
182
183  t = (t >> 3) & 0x3f; /* Bytes already in shsInfo->data */
184
185  /* Handle any leading odd-sized chunks */
186
187  if (t) {
188    uint8_t* p = static_cast<uint8_t*>(ctx->in + t);
189
190    t = 64 - t;
191    if (len < t) {
192      memcpy(p, buf, len);
193      return;
194    }
195    memcpy(p, buf, t);
196    byteReverse(ctx->in, 16);
197    MD5Transform(ctx->buf, reinterpret_cast<uint32_t*>(ctx->in));
198    buf += t;
199    len -= t;
200  }
201
202  /* Process data in 64-byte chunks */
203
204  while (len >= 64) {
205    memcpy(ctx->in, buf, 64);
206    byteReverse(ctx->in, 16);
207    MD5Transform(ctx->buf, reinterpret_cast<uint32_t*>(ctx->in));
208    buf += 64;
209    len -= 64;
210  }
211
212  /* Handle any remaining bytes of data. */
213
214  memcpy(ctx->in, buf, len);
215}
216
217/*
218 * Final wrapup - pad to 64-byte boundary with the bit pattern
219 * 1 0* (64-bit count of bits processed, MSB-first)
220 */
221void MD5Final(MD5Digest* digest, MD5Context* context) {
222  struct Context* ctx = reinterpret_cast<struct Context*>(context);
223  unsigned count;
224  uint8_t* p;
225
226  /* Compute number of bytes mod 64 */
227  count = (ctx->bits[0] >> 3) & 0x3F;
228
229  /* Set the first char of padding to 0x80.  This is safe since there is
230     always at least one byte free */
231  p = ctx->in + count;
232  *p++ = 0x80;
233
234  /* Bytes of padding needed to make 64 bytes */
235  count = 64 - 1 - count;
236
237  /* Pad out to 56 mod 64 */
238  if (count < 8) {
239    /* Two lots of padding:  Pad the first block to 64 bytes */
240    memset(p, 0, count);
241    byteReverse(ctx->in, 16);
242    MD5Transform(ctx->buf, reinterpret_cast<uint32_t*>(ctx->in));
243
244    /* Now fill the next block with 56 bytes */
245    memset(ctx->in, 0, 56);
246  } else {
247    /* Pad block to 56 bytes */
248    memset(p, 0, count - 8);
249  }
250  byteReverse(ctx->in, 14);
251
252  /* Append length in bits and transform */
253  memcpy(&ctx->in[14 * sizeof(ctx->bits[0])], &ctx->bits[0],
254         sizeof(ctx->bits[0]));
255  memcpy(&ctx->in[15 * sizeof(ctx->bits[1])], &ctx->bits[1],
256         sizeof(ctx->bits[1]));
257
258  MD5Transform(ctx->buf, reinterpret_cast<uint32_t*>(ctx->in));
259  byteReverse(reinterpret_cast<uint8_t*>(ctx->buf), 4);
260  memcpy(digest->a, ctx->buf, 16);
261  memset(ctx, 0, sizeof(*ctx)); /* In case it's sensitive */
262}
263
264void MD5IntermediateFinal(MD5Digest* digest, const MD5Context* context) {
265  /* MD5Final mutates the MD5Context*. Make a copy for generating the
266     intermediate value. */
267  MD5Context context_copy;
268  memcpy(&context_copy, context, sizeof(context_copy));
269  MD5Final(digest, &context_copy);
270}
271
272std::string MD5DigestToBase16(const MD5Digest& digest) {
273  static char const zEncode[] = "0123456789abcdef";
274
275  std::string ret;
276  ret.resize(32);
277
278  for (int i = 0, j = 0; i < 16; i++, j += 2) {
279    uint8_t a = digest.a[i];
280    ret[j] = zEncode[(a >> 4) & 0xf];
281    ret[j + 1] = zEncode[a & 0xf];
282  }
283  return ret;
284}
285
286void MD5Sum(const void* data, size_t length, MD5Digest* digest) {
287  MD5Context ctx;
288  MD5Init(&ctx);
289  MD5Update(&ctx, StringPiece(reinterpret_cast<const char*>(data), length));
290  MD5Final(digest, &ctx);
291}
292
293std::string MD5String(const StringPiece& str) {
294  MD5Digest digest;
295  MD5Sum(str.data(), str.length(), &digest);
296  return MD5DigestToBase16(digest);
297}
298
299}  // namespace base
300