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 * LIC: GPL
17 *
18 */
19#include <string.h>		/* for memcpy() */
20#include "md5.h"
21
22void byteReverse(unsigned char *buf, unsigned longs);
23
24/*
25 * Note: this code is harmless on little-endian machines.
26 */
27void byteReverse(unsigned char *buf, unsigned longs)
28{
29    uint32 t;
30    do {
31	t = (uint32) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
32	    ((unsigned) buf[1] << 8 | buf[0]);
33	*(uint32 *) buf = t;
34	buf += 4;
35    } while (--longs);
36}
37
38/*
39 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
40 * initialization constants.
41 */
42void MD5Init(struct MD5Context *ctx)
43{
44    ctx->buf[0] = 0x67452301;
45    ctx->buf[1] = 0xefcdab89;
46    ctx->buf[2] = 0x98badcfe;
47    ctx->buf[3] = 0x10325476;
48
49    ctx->bits[0] = 0;
50    ctx->bits[1] = 0;
51}
52
53/*
54 * Update context to reflect the concatenation of another buffer full
55 * of bytes.
56 */
57void MD5Update(struct MD5Context *ctx, unsigned char const *buf, unsigned len)
58{
59    uint32 t;
60
61    /* Update bitcount */
62
63    t = ctx->bits[0];
64    if ((ctx->bits[0] = t + ((uint32) len << 3)) < t)
65	ctx->bits[1]++;		/* Carry from low to high */
66    ctx->bits[1] += len >> 29;
67
68    t = (t >> 3) & 0x3f;	/* Bytes already in shsInfo->data */
69
70    /* Handle any leading odd-sized chunks */
71
72    if (t) {
73	unsigned char *p = (unsigned char *) ctx->in + t;
74
75	t = 64 - t;
76	if (len < t) {
77	    memcpy(p, buf, len);
78	    return;
79	}
80	memcpy(p, buf, t);
81	byteReverse(ctx->in, 16);
82	MD5Transform(ctx->buf, (uint32 *) ctx->in);
83	buf += t;
84	len -= t;
85    }
86    /* Process data in 64-byte chunks */
87
88    while (len >= 64) {
89	memcpy(ctx->in, buf, 64);
90	byteReverse(ctx->in, 16);
91	MD5Transform(ctx->buf, (uint32 *) ctx->in);
92	buf += 64;
93	len -= 64;
94    }
95
96    /* Handle any remaining bytes of data. */
97
98    memcpy(ctx->in, buf, len);
99}
100
101/*
102 * Final wrapup - pad to 64-byte boundary with the bit pattern
103 * 1 0* (64-bit count of bits processed, MSB-first)
104 */
105void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
106{
107    unsigned count;
108    unsigned char *p;
109
110    /* Compute number of bytes mod 64 */
111    count = (ctx->bits[0] >> 3) & 0x3F;
112
113    /* Set the first char of padding to 0x80.  This is safe since there is
114       always at least one byte free */
115    p = ctx->in + count;
116    *p++ = 0x80;
117
118    /* Bytes of padding needed to make 64 bytes */
119    count = 64 - 1 - count;
120
121    /* Pad out to 56 mod 64 */
122    if (count < 8) {
123	/* Two lots of padding:  Pad the first block to 64 bytes */
124	memset(p, 0, count);
125	byteReverse(ctx->in, 16);
126	MD5Transform(ctx->buf, (uint32 *) ctx->in);
127
128	/* Now fill the next block with 56 bytes */
129	memset(ctx->in, 0, 56);
130    } else {
131	/* Pad block to 56 bytes */
132	memset(p, 0, count - 8);
133    }
134    byteReverse(ctx->in, 14);
135
136    /* Append length in bits and transform */
137    ((uint32 *) ctx->in)[14] = ctx->bits[0];
138    ((uint32 *) ctx->in)[15] = ctx->bits[1];
139
140    MD5Transform(ctx->buf, (uint32 *) ctx->in);
141    byteReverse((unsigned char *) ctx->buf, 4);
142    memcpy(digest, ctx->buf, 16);
143    memset(ctx, 0, sizeof(ctx));	/* In case it's sensitive */
144}
145
146#ifndef ASM_MD5
147
148/* The four core functions - F1 is optimized somewhat */
149
150/* #define F1(x, y, z) (x & y | ~x & z) */
151#define F1(x, y, z) (z ^ (x & (y ^ z)))
152#define F2(x, y, z) F1(z, x, y)
153#define F3(x, y, z) (x ^ y ^ z)
154#define F4(x, y, z) (y ^ (x | ~z))
155
156/* This is the central step in the MD5 algorithm. */
157#define MD5STEP(f, w, x, y, z, data, s) \
158	( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
159
160/*
161 * The core of the MD5 algorithm, this alters an existing MD5 hash to
162 * reflect the addition of 16 longwords of new data.  MD5Update blocks
163 * the data and converts bytes into longwords for this routine.
164 */
165void MD5Transform(uint32 buf[4], uint32 const in[16])
166{
167    register uint32 a, b, c, d;
168
169    a = buf[0];
170    b = buf[1];
171    c = buf[2];
172    d = buf[3];
173
174    MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
175    MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
176    MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
177    MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
178    MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
179    MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
180    MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
181    MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
182    MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
183    MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
184    MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
185    MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
186    MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
187    MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
188    MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
189    MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
190
191    MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
192    MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
193    MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
194    MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
195    MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
196    MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
197    MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
198    MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
199    MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
200    MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
201    MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
202    MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
203    MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
204    MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
205    MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
206    MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
207
208    MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
209    MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
210    MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
211    MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
212    MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
213    MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
214    MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
215    MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
216    MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
217    MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
218    MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
219    MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
220    MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
221    MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
222    MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
223    MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
224
225    MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
226    MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
227    MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
228    MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
229    MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
230    MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
231    MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
232    MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
233    MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
234    MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
235    MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
236    MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
237    MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
238    MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
239    MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
240    MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
241
242    buf[0] += a;
243    buf[1] += b;
244    buf[2] += c;
245    buf[3] += d;
246}
247
248#endif
249