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 "base/basictypes.h"
27
28namespace {
29
30struct Context {
31  uint32 buf[4];
32  uint32 bits[2];
33  unsigned char in[64];
34};
35
36/*
37 * Note: this code is harmless on little-endian machines.
38 */
39void byteReverse(unsigned char *buf, unsigned longs) {
40        uint32 t;
41        do {
42                t = (uint32)((unsigned)buf[3]<<8 | buf[2]) << 16 |
43                            ((unsigned)buf[1]<<8 | buf[0]);
44                *(uint32 *)buf = t;
45                buf += 4;
46        } while (--longs);
47}
48
49/* The four core functions - F1 is optimized somewhat */
50
51/* #define F1(x, y, z) (x & y | ~x & z) */
52#define F1(x, y, z) (z ^ (x & (y ^ z)))
53#define F2(x, y, z) F1(z, x, y)
54#define F3(x, y, z) (x ^ y ^ z)
55#define F4(x, y, z) (y ^ (x | ~z))
56
57/* This is the central step in the MD5 algorithm. */
58#define MD5STEP(f, w, x, y, z, data, s) \
59        ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
60
61/*
62 * The core of the MD5 algorithm, this alters an existing MD5 hash to
63 * reflect the addition of 16 longwords of new data.  MD5Update blocks
64 * the data and converts bytes into longwords for this routine.
65 */
66void MD5Transform(uint32 buf[4], const uint32 in[16]) {
67        register uint32 a, b, c, d;
68
69        a = buf[0];
70        b = buf[1];
71        c = buf[2];
72        d = buf[3];
73
74        MD5STEP(F1, a, b, c, d, in[ 0]+0xd76aa478,  7);
75        MD5STEP(F1, d, a, b, c, in[ 1]+0xe8c7b756, 12);
76        MD5STEP(F1, c, d, a, b, in[ 2]+0x242070db, 17);
77        MD5STEP(F1, b, c, d, a, in[ 3]+0xc1bdceee, 22);
78        MD5STEP(F1, a, b, c, d, in[ 4]+0xf57c0faf,  7);
79        MD5STEP(F1, d, a, b, c, in[ 5]+0x4787c62a, 12);
80        MD5STEP(F1, c, d, a, b, in[ 6]+0xa8304613, 17);
81        MD5STEP(F1, b, c, d, a, in[ 7]+0xfd469501, 22);
82        MD5STEP(F1, a, b, c, d, in[ 8]+0x698098d8,  7);
83        MD5STEP(F1, d, a, b, c, in[ 9]+0x8b44f7af, 12);
84        MD5STEP(F1, c, d, a, b, in[10]+0xffff5bb1, 17);
85        MD5STEP(F1, b, c, d, a, in[11]+0x895cd7be, 22);
86        MD5STEP(F1, a, b, c, d, in[12]+0x6b901122,  7);
87        MD5STEP(F1, d, a, b, c, in[13]+0xfd987193, 12);
88        MD5STEP(F1, c, d, a, b, in[14]+0xa679438e, 17);
89        MD5STEP(F1, b, c, d, a, in[15]+0x49b40821, 22);
90
91        MD5STEP(F2, a, b, c, d, in[ 1]+0xf61e2562,  5);
92        MD5STEP(F2, d, a, b, c, in[ 6]+0xc040b340,  9);
93        MD5STEP(F2, c, d, a, b, in[11]+0x265e5a51, 14);
94        MD5STEP(F2, b, c, d, a, in[ 0]+0xe9b6c7aa, 20);
95        MD5STEP(F2, a, b, c, d, in[ 5]+0xd62f105d,  5);
96        MD5STEP(F2, d, a, b, c, in[10]+0x02441453,  9);
97        MD5STEP(F2, c, d, a, b, in[15]+0xd8a1e681, 14);
98        MD5STEP(F2, b, c, d, a, in[ 4]+0xe7d3fbc8, 20);
99        MD5STEP(F2, a, b, c, d, in[ 9]+0x21e1cde6,  5);
100        MD5STEP(F2, d, a, b, c, in[14]+0xc33707d6,  9);
101        MD5STEP(F2, c, d, a, b, in[ 3]+0xf4d50d87, 14);
102        MD5STEP(F2, b, c, d, a, in[ 8]+0x455a14ed, 20);
103        MD5STEP(F2, a, b, c, d, in[13]+0xa9e3e905,  5);
104        MD5STEP(F2, d, a, b, c, in[ 2]+0xfcefa3f8,  9);
105        MD5STEP(F2, c, d, a, b, in[ 7]+0x676f02d9, 14);
106        MD5STEP(F2, b, c, d, a, in[12]+0x8d2a4c8a, 20);
107
108        MD5STEP(F3, a, b, c, d, in[ 5]+0xfffa3942,  4);
109        MD5STEP(F3, d, a, b, c, in[ 8]+0x8771f681, 11);
110        MD5STEP(F3, c, d, a, b, in[11]+0x6d9d6122, 16);
111        MD5STEP(F3, b, c, d, a, in[14]+0xfde5380c, 23);
112        MD5STEP(F3, a, b, c, d, in[ 1]+0xa4beea44,  4);
113        MD5STEP(F3, d, a, b, c, in[ 4]+0x4bdecfa9, 11);
114        MD5STEP(F3, c, d, a, b, in[ 7]+0xf6bb4b60, 16);
115        MD5STEP(F3, b, c, d, a, in[10]+0xbebfbc70, 23);
116        MD5STEP(F3, a, b, c, d, in[13]+0x289b7ec6,  4);
117        MD5STEP(F3, d, a, b, c, in[ 0]+0xeaa127fa, 11);
118        MD5STEP(F3, c, d, a, b, in[ 3]+0xd4ef3085, 16);
119        MD5STEP(F3, b, c, d, a, in[ 6]+0x04881d05, 23);
120        MD5STEP(F3, a, b, c, d, in[ 9]+0xd9d4d039,  4);
121        MD5STEP(F3, d, a, b, c, in[12]+0xe6db99e5, 11);
122        MD5STEP(F3, c, d, a, b, in[15]+0x1fa27cf8, 16);
123        MD5STEP(F3, b, c, d, a, in[ 2]+0xc4ac5665, 23);
124
125        MD5STEP(F4, a, b, c, d, in[ 0]+0xf4292244,  6);
126        MD5STEP(F4, d, a, b, c, in[ 7]+0x432aff97, 10);
127        MD5STEP(F4, c, d, a, b, in[14]+0xab9423a7, 15);
128        MD5STEP(F4, b, c, d, a, in[ 5]+0xfc93a039, 21);
129        MD5STEP(F4, a, b, c, d, in[12]+0x655b59c3,  6);
130        MD5STEP(F4, d, a, b, c, in[ 3]+0x8f0ccc92, 10);
131        MD5STEP(F4, c, d, a, b, in[10]+0xffeff47d, 15);
132        MD5STEP(F4, b, c, d, a, in[ 1]+0x85845dd1, 21);
133        MD5STEP(F4, a, b, c, d, in[ 8]+0x6fa87e4f,  6);
134        MD5STEP(F4, d, a, b, c, in[15]+0xfe2ce6e0, 10);
135        MD5STEP(F4, c, d, a, b, in[ 6]+0xa3014314, 15);
136        MD5STEP(F4, b, c, d, a, in[13]+0x4e0811a1, 21);
137        MD5STEP(F4, a, b, c, d, in[ 4]+0xf7537e82,  6);
138        MD5STEP(F4, d, a, b, c, in[11]+0xbd3af235, 10);
139        MD5STEP(F4, c, d, a, b, in[ 2]+0x2ad7d2bb, 15);
140        MD5STEP(F4, b, c, d, a, in[ 9]+0xeb86d391, 21);
141
142        buf[0] += a;
143        buf[1] += b;
144        buf[2] += c;
145        buf[3] += d;
146}
147
148}  // namespace
149
150namespace base {
151
152/*
153 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
154 * initialization constants.
155 */
156void MD5Init(MD5Context* context) {
157        struct Context *ctx = (struct Context *)context;
158        ctx->buf[0] = 0x67452301;
159        ctx->buf[1] = 0xefcdab89;
160        ctx->buf[2] = 0x98badcfe;
161        ctx->buf[3] = 0x10325476;
162        ctx->bits[0] = 0;
163        ctx->bits[1] = 0;
164}
165
166/*
167 * Update context to reflect the concatenation of another buffer full
168 * of bytes.
169 */
170void MD5Update(MD5Context* context, const StringPiece& data) {
171        const unsigned char* inbuf = (const unsigned char*)data.data();
172        size_t len = data.size();
173        struct Context *ctx = (struct Context *)context;
174        const unsigned char* buf = (const unsigned char*)inbuf;
175        uint32 t;
176
177        /* Update bitcount */
178
179        t = ctx->bits[0];
180        if ((ctx->bits[0] = t + ((uint32)len << 3)) < t)
181                ctx->bits[1]++; /* Carry from low to high */
182        ctx->bits[1] += static_cast<uint32>(len >> 29);
183
184        t = (t >> 3) & 0x3f;    /* Bytes already in shsInfo->data */
185
186        /* Handle any leading odd-sized chunks */
187
188        if (t) {
189                unsigned char *p = (unsigned char *)ctx->in + t;
190
191                t = 64-t;
192                if (len < t) {
193                        memcpy(p, buf, len);
194                        return;
195                }
196                memcpy(p, buf, t);
197                byteReverse(ctx->in, 16);
198                MD5Transform(ctx->buf, (uint32 *)ctx->in);
199                buf += t;
200                len -= t;
201        }
202
203        /* Process data in 64-byte chunks */
204
205        while (len >= 64) {
206                memcpy(ctx->in, buf, 64);
207                byteReverse(ctx->in, 16);
208                MD5Transform(ctx->buf, (uint32 *)ctx->in);
209                buf += 64;
210                len -= 64;
211        }
212
213        /* Handle any remaining bytes of data. */
214
215        memcpy(ctx->in, buf, len);
216}
217
218/*
219 * Final wrapup - pad to 64-byte boundary with the bit pattern
220 * 1 0* (64-bit count of bits processed, MSB-first)
221 */
222void MD5Final(MD5Digest* digest, MD5Context* context) {
223        struct Context *ctx = (struct Context *)context;
224        unsigned count;
225        unsigned char *p;
226
227        /* Compute number of bytes mod 64 */
228        count = (ctx->bits[0] >> 3) & 0x3F;
229
230        /* Set the first char of padding to 0x80.  This is safe since there is
231           always at least one byte free */
232        p = ctx->in + count;
233        *p++ = 0x80;
234
235        /* Bytes of padding needed to make 64 bytes */
236        count = 64 - 1 - count;
237
238        /* Pad out to 56 mod 64 */
239        if (count < 8) {
240                /* Two lots of padding:  Pad the first block to 64 bytes */
241                memset(p, 0, count);
242                byteReverse(ctx->in, 16);
243                MD5Transform(ctx->buf, (uint32 *)ctx->in);
244
245                /* Now fill the next block with 56 bytes */
246                memset(ctx->in, 0, 56);
247        } else {
248                /* Pad block to 56 bytes */
249                memset(p, 0, count-8);
250        }
251        byteReverse(ctx->in, 14);
252
253        /* Append length in bits and transform */
254        memcpy(&ctx->in[14 * sizeof(ctx->bits[0])],
255               &ctx->bits[0],
256               sizeof(ctx->bits[0]));
257        memcpy(&ctx->in[15 * sizeof(ctx->bits[1])],
258               &ctx->bits[1],
259               sizeof(ctx->bits[1]));
260
261        MD5Transform(ctx->buf, (uint32 *)ctx->in);
262        byteReverse((unsigned char *)ctx->buf, 4);
263        memcpy(digest->a, ctx->buf, 16);
264        memset(ctx, 0, sizeof(*ctx));    /* In case it's sensitive */
265}
266
267void MD5IntermediateFinal(MD5Digest* digest, const MD5Context* context) {
268  /* MD5Final mutates the MD5Context*. Make a copy for generating the
269     intermediate value. */
270  MD5Context context_copy;
271  memcpy(&context_copy, context, sizeof(context_copy));
272  MD5Final(digest, &context_copy);
273}
274
275std::string MD5DigestToBase16(const MD5Digest& digest) {
276  static char const zEncode[] = "0123456789abcdef";
277
278  std::string ret;
279  ret.resize(32);
280
281  int j = 0;
282  for (int i = 0; i < 16; i ++) {
283    int a = digest.a[i];
284    ret[j++] = zEncode[(a>>4)&0xf];
285    ret[j++] = zEncode[a & 0xf];
286  }
287  return ret;
288}
289
290void MD5Sum(const void* data, size_t length, MD5Digest* digest) {
291  MD5Context ctx;
292  MD5Init(&ctx);
293  MD5Update(&ctx,
294            StringPiece(reinterpret_cast<const char*>(data), length));
295  MD5Final(digest, &ctx);
296}
297
298std::string MD5String(const StringPiece& str) {
299  MD5Digest digest;
300  MD5Sum(str.data(), str.length(), &digest);
301  return MD5DigestToBase16(digest);
302}
303
304}  // namespace base
305