md5_utils.c revision ba164dffc5a6795bce97fae02b51ccf3330e15e4 
1/*
2 * This code implements the MD5 message-digest algorithm.
3 * The algorithm is due to Ron Rivest.  This code was
4 * written by Colin Plumb in 1993, no copyright is claimed.
5 * This code is in the public domain; do with it what you wish.
6 *
7 * Equivalent code is available from RSA Data Security, Inc.
8 * This code has been tested against that, and is equivalent,
9 * except that you don't need to include two pages of legalese
10 * with every copy.
11 *
12 * To compute the message digest of a chunk of bytes, declare an
13 * MD5Context structure, pass it to MD5Init, call MD5Update as
14 * needed on buffers full of bytes, and then call MD5Final, which
15 * will fill a supplied 16-byte array with the digest.
16 *
17 * Changed so as no longer to depend on Colin Plumb's `usual.h' header
18 * definitions
19 *  - Ian Jackson <ian@chiark.greenend.org.uk>.
20 * Still in the public domain.
21 */
22
23#include <string.h>   /* for memcpy() */
24
25#include "md5_utils.h"
26
27void
28byteSwap(UWORD32 *buf, unsigned words) {
29  md5byte *p;
30
31  /* Only swap bytes for big endian machines */
32  int i = 1;
33
34  if (*(char *)&i == 1)
35    return;
36
37  p = (md5byte *)buf;
38
39  do {
40    *buf++ = (UWORD32)((unsigned)p[3] << 8 | p[2]) << 16 |
41             ((unsigned)p[1] << 8 | p[0]);
42    p += 4;
43  } while (--words);
44}
45
46/*
47 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
48 * initialization constants.
49 */
50void
51MD5Init(struct MD5Context *ctx) {
52  ctx->buf[0] = 0x67452301;
53  ctx->buf[1] = 0xefcdab89;
54  ctx->buf[2] = 0x98badcfe;
55  ctx->buf[3] = 0x10325476;
56
57  ctx->bytes[0] = 0;
58  ctx->bytes[1] = 0;
59}
60
61/*
62 * Update context to reflect the concatenation of another buffer full
63 * of bytes.
64 */
65void
66MD5Update(struct MD5Context *ctx, md5byte const *buf, unsigned len) {
67  UWORD32 t;
68
69  /* Update byte count */
70
71  t = ctx->bytes[0];
72
73  if ((ctx->bytes[0] = t + len) < t)
74    ctx->bytes[1]++;  /* Carry from low to high */
75
76  t = 64 - (t & 0x3f);  /* Space available in ctx->in (at least 1) */
77
78  if (t > len) {
79    memcpy((md5byte *)ctx->in + 64 - t, buf, len);
80    return;
81  }
82
83  /* First chunk is an odd size */
84  memcpy((md5byte *)ctx->in + 64 - t, buf, t);
85  byteSwap(ctx->in, 16);
86  MD5Transform(ctx->buf, ctx->in);
87  buf += t;
88  len -= t;
89
90  /* Process data in 64-byte chunks */
91  while (len >= 64) {
92    memcpy(ctx->in, buf, 64);
93    byteSwap(ctx->in, 16);
94    MD5Transform(ctx->buf, ctx->in);
95    buf += 64;
96    len -= 64;
97  }
98
99  /* Handle any remaining bytes of data. */
100  memcpy(ctx->in, buf, len);
101}
102
103/*
104 * Final wrapup - pad to 64-byte boundary with the bit pattern
105 * 1 0* (64-bit count of bits processed, MSB-first)
106 */
107void
108MD5Final(md5byte digest[16], struct MD5Context *ctx) {
109  int count = ctx->bytes[0] & 0x3f; /* Number of bytes in ctx->in */
110  md5byte *p = (md5byte *)ctx->in + count;
111
112  /* Set the first char of padding to 0x80.  There is always room. */
113  *p++ = 0x80;
114
115  /* Bytes of padding needed to make 56 bytes (-8..55) */
116  count = 56 - 1 - count;
117
118  if (count < 0) {  /* Padding forces an extra block */
119    memset(p, 0, count + 8);
120    byteSwap(ctx->in, 16);
121    MD5Transform(ctx->buf, ctx->in);
122    p = (md5byte *)ctx->in;
123    count = 56;
124  }
125
126  memset(p, 0, count);
127  byteSwap(ctx->in, 14);
128
129  /* Append length in bits and transform */
130  ctx->in[14] = ctx->bytes[0] << 3;
131  ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
132  MD5Transform(ctx->buf, ctx->in);
133
134  byteSwap(ctx->buf, 4);
135  memcpy(digest, ctx->buf, 16);
136  memset(ctx, 0, sizeof(*ctx)); /* In case it's sensitive */
137}
138
139#ifndef ASM_MD5
140
141/* The four core functions - F1 is optimized somewhat */
142
143/* #define F1(x, y, z) (x & y | ~x & z) */
144#define F1(x, y, z) (z ^ (x & (y ^ z)))
145#define F2(x, y, z) F1(z, x, y)
146#define F3(x, y, z) (x ^ y ^ z)
147#define F4(x, y, z) (y ^ (x | ~z))
148
149/* This is the central step in the MD5 algorithm. */
150#define MD5STEP(f,w,x,y,z,in,s) \
151  (w += f(x,y,z) + in, w = (w<<s | w>>(32-s)) + x)
152
153/*
154 * The core of the MD5 algorithm, this alters an existing MD5 hash to
155 * reflect the addition of 16 longwords of new data.  MD5Update blocks
156 * the data and converts bytes into longwords for this routine.
157 */
158void
159MD5Transform(UWORD32 buf[4], UWORD32 const in[16]) {
160  register UWORD32 a, b, c, d;
161
162  a = buf[0];
163  b = buf[1];
164  c = buf[2];
165  d = buf[3];
166
167  MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
168  MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
169  MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
170  MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
171  MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
172  MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
173  MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
174  MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
175  MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
176  MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
177  MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
178  MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
179  MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
180  MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
181  MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
182  MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
183
184  MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
185  MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
186  MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
187  MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
188  MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
189  MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
190  MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
191  MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
192  MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
193  MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
194  MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
195  MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
196  MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
197  MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
198  MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
199  MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
200
201  MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
202  MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
203  MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
204  MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
205  MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
206  MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
207  MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
208  MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
209  MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
210  MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
211  MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
212  MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
213  MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
214  MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
215  MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
216  MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
217
218  MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
219  MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
220  MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
221  MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
222  MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
223  MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
224  MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
225  MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
226  MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
227  MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
228  MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
229  MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
230  MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
231  MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
232  MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
233  MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
234
235  buf[0] += a;
236  buf[1] += b;
237  buf[2] += c;
238  buf[3] += d;
239}
240
241#endif
242