1/*
2 * written by Colin Plumb in 1993, no copyright is claimed.
3 * This code is in the public domain; do with it what you wish.
4 *
5 * Equivalent code is available from RSA Data Security, Inc.
6 * This code has been tested against that, and is equivalent,
7 * except that you don't need to include two pages of legalese
8 * with every copy.
9 *
10 * To compute the message digest of a chunk of bytes, declare an
11 * MD5Context structure, pass it to MD5Init, call MD5Update as
12 * needed on buffers full of bytes, and then call MD5Final, which
13 * will fill a supplied 16-byte array with the digest.
14 */
15
16#include <string.h>
17
18#include "common/md5.h"
19
20namespace google_breakpad {
21
22#ifndef WORDS_BIGENDIAN
23#define byteReverse(buf, len)   /* Nothing */
24#else
25/*
26 * Note: this code is harmless on little-endian machines.
27 */
28static void byteReverse(unsigned char *buf, unsigned longs)
29{
30  u32 t;
31  do {
32    t = (u32) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
33      ((unsigned) buf[1] << 8 | buf[0]);
34    *(u32 *) buf = t;
35    buf += 4;
36  } while (--longs);
37}
38#endif
39
40static void MD5Transform(u32 buf[4], u32 const in[16]);
41
42/*
43 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
44 * initialization constants.
45 */
46void MD5Init(struct MD5Context *ctx)
47{
48  ctx->buf[0] = 0x67452301;
49  ctx->buf[1] = 0xefcdab89;
50  ctx->buf[2] = 0x98badcfe;
51  ctx->buf[3] = 0x10325476;
52
53  ctx->bits[0] = 0;
54  ctx->bits[1] = 0;
55}
56
57/*
58 * Update context to reflect the concatenation of another buffer full
59 * of bytes.
60 */
61void MD5Update(struct MD5Context *ctx, unsigned char const *buf, size_t len)
62{
63  u32 t;
64
65  /* Update bitcount */
66
67  t = ctx->bits[0];
68  if ((ctx->bits[0] = t + ((u32) len << 3)) < t)
69    ctx->bits[1]++;         /* Carry from low to high */
70  ctx->bits[1] += len >> 29;
71
72  t = (t >> 3) & 0x3f;        /* Bytes already in shsInfo->data */
73
74  /* Handle any leading odd-sized chunks */
75
76  if (t) {
77    unsigned char *p = (unsigned char *) ctx->in + t;
78
79    t = 64 - t;
80    if (len < t) {
81      memcpy(p, buf, len);
82      return;
83    }
84    memcpy(p, buf, t);
85    byteReverse(ctx->in, 16);
86    MD5Transform(ctx->buf, (u32 *) ctx->in);
87    buf += t;
88    len -= t;
89  }
90  /* Process data in 64-byte chunks */
91
92  while (len >= 64) {
93    memcpy(ctx->in, buf, 64);
94    byteReverse(ctx->in, 16);
95    MD5Transform(ctx->buf, (u32 *) ctx->in);
96    buf += 64;
97    len -= 64;
98  }
99
100  /* Handle any remaining bytes of data. */
101
102  memcpy(ctx->in, buf, len);
103}
104
105/*
106 * Final wrapup - pad to 64-byte boundary with the bit pattern
107 * 1 0* (64-bit count of bits processed, MSB-first)
108 */
109void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
110{
111  unsigned count;
112  unsigned char *p;
113
114  /* Compute number of bytes mod 64 */
115  count = (ctx->bits[0] >> 3) & 0x3F;
116
117  /* Set the first char of padding to 0x80.  This is safe since there is
118     always at least one byte free */
119  p = ctx->in + count;
120  *p++ = 0x80;
121
122  /* Bytes of padding needed to make 64 bytes */
123  count = 64 - 1 - count;
124
125  /* Pad out to 56 mod 64 */
126  if (count < 8) {
127    /* Two lots of padding:  Pad the first block to 64 bytes */
128    memset(p, 0, count);
129    byteReverse(ctx->in, 16);
130    MD5Transform(ctx->buf, (u32 *) ctx->in);
131
132    /* Now fill the next block with 56 bytes */
133    memset(ctx->in, 0, 56);
134  } else {
135    /* Pad block to 56 bytes */
136    memset(p, 0, count - 8);
137  }
138  byteReverse(ctx->in, 14);
139
140  /* Append length in bits and transform */
141  ((u32 *) ctx->in)[14] = ctx->bits[0];
142  ((u32 *) ctx->in)[15] = ctx->bits[1];
143
144  MD5Transform(ctx->buf, (u32 *) ctx->in);
145  byteReverse((unsigned char *) ctx->buf, 4);
146  memcpy(digest, ctx->buf, 16);
147  memset(ctx, 0, sizeof(*ctx));        /* In case it's sensitive */
148}
149
150/* The four core functions - F1 is optimized somewhat */
151
152/* #define F1(x, y, z) (x & y | ~x & z) */
153#define F1(x, y, z) (z ^ (x & (y ^ z)))
154#define F2(x, y, z) F1(z, x, y)
155#define F3(x, y, z) (x ^ y ^ z)
156#define F4(x, y, z) (y ^ (x | ~z))
157
158/* This is the central step in the MD5 algorithm. */
159#define MD5STEP(f, w, x, y, z, data, s) \
160  ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
161
162/*
163 * The core of the MD5 algorithm, this alters an existing MD5 hash to
164 * reflect the addition of 16 longwords of new data.  MD5Update blocks
165 * the data and converts bytes into longwords for this routine.
166 */
167static void MD5Transform(u32 buf[4], u32 const in[16])
168{
169  u32 a, b, c, d;
170
171  a = buf[0];
172  b = buf[1];
173  c = buf[2];
174  d = buf[3];
175
176  MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
177  MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
178  MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
179  MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
180  MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
181  MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
182  MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
183  MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
184  MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
185  MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
186  MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
187  MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
188  MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
189  MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
190  MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
191  MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
192
193  MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
194  MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
195  MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
196  MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
197  MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
198  MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
199  MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
200  MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
201  MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
202  MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
203  MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
204  MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
205  MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
206  MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
207  MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
208  MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
209
210  MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
211  MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
212  MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
213  MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
214  MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
215  MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
216  MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
217  MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
218  MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
219  MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
220  MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
221  MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
222  MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
223  MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
224  MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
225  MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
226
227  MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
228  MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
229  MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
230  MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
231  MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
232  MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
233  MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
234  MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
235  MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
236  MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
237  MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
238  MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
239  MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
240  MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
241  MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
242  MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
243
244  buf[0] += a;
245  buf[1] += b;
246  buf[2] += c;
247  buf[3] += d;
248}
249
250}  // namespace google_breakpad
251
252