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#include "fcint.h"
18
19struct MD5Context {
20        FcChar32 buf[4];
21        FcChar32 bits[2];
22        unsigned char in[64];
23};
24
25static void MD5Init(struct MD5Context *ctx);
26static void MD5Update(struct MD5Context *ctx, const unsigned char *buf, unsigned len);
27static void MD5Final(unsigned char digest[16], struct MD5Context *ctx);
28static void MD5Transform(FcChar32 buf[4], FcChar32 in[16]);
29
30#ifndef WORDS_BIGENDIAN
31#define byteReverse(buf, len)	/* Nothing */
32#else
33/*
34 * Note: this code is harmless on little-endian machines.
35 */
36void byteReverse(unsigned char *buf, unsigned longs)
37{
38    FcChar32 t;
39    do {
40	t = (FcChar32) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
41	    ((unsigned) buf[1] << 8 | buf[0]);
42	*(FcChar32 *) buf = t;
43	buf += 4;
44    } while (--longs);
45}
46#endif
47
48/*
49 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
50 * initialization constants.
51 */
52static void MD5Init(struct MD5Context *ctx)
53{
54    ctx->buf[0] = 0x67452301;
55    ctx->buf[1] = 0xefcdab89;
56    ctx->buf[2] = 0x98badcfe;
57    ctx->buf[3] = 0x10325476;
58
59    ctx->bits[0] = 0;
60    ctx->bits[1] = 0;
61}
62
63/*
64 * Update context to reflect the concatenation of another buffer full
65 * of bytes.
66 */
67static void MD5Update(struct MD5Context *ctx, const unsigned char *buf, unsigned len)
68{
69    FcChar32 t;
70
71    /* Update bitcount */
72
73    t = ctx->bits[0];
74    if ((ctx->bits[0] = t + ((FcChar32) len << 3)) < t)
75	ctx->bits[1]++; 	/* Carry from low to high */
76    ctx->bits[1] += len >> 29;
77
78    t = (t >> 3) & 0x3f;	/* Bytes already in shsInfo->data */
79
80    /* Handle any leading odd-sized chunks */
81
82    if (t) {
83	unsigned char *p = (unsigned char *) ctx->in + t;
84
85	t = 64 - t;
86	if (len < t) {
87	    memcpy(p, buf, len);
88	    return;
89	}
90	memcpy(p, buf, t);
91	byteReverse(ctx->in, 16);
92	MD5Transform(ctx->buf, (FcChar32 *) ctx->in);
93	buf += t;
94	len -= t;
95    }
96    /* Process data in 64-byte chunks */
97
98    while (len >= 64) {
99	memcpy(ctx->in, buf, 64);
100	byteReverse(ctx->in, 16);
101	MD5Transform(ctx->buf, (FcChar32 *) ctx->in);
102	buf += 64;
103	len -= 64;
104    }
105
106    /* Handle any remaining bytes of data. */
107
108    memcpy(ctx->in, buf, len);
109}
110
111/*
112 * Final wrapup - pad to 64-byte boundary with the bit pattern
113 * 1 0* (64-bit count of bits processed, MSB-first)
114 */
115static void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
116{
117    unsigned count;
118    unsigned char *p;
119
120    /* Compute number of bytes mod 64 */
121    count = (ctx->bits[0] >> 3) & 0x3F;
122
123    /* Set the first char of padding to 0x80.  This is safe since there is
124       always at least one byte free */
125    p = ctx->in + count;
126    *p++ = 0x80;
127
128    /* Bytes of padding needed to make 64 bytes */
129    count = 64 - 1 - count;
130
131    /* Pad out to 56 mod 64 */
132    if (count < 8) {
133	/* Two lots of padding:  Pad the first block to 64 bytes */
134	memset(p, 0, count);
135	byteReverse(ctx->in, 16);
136	MD5Transform(ctx->buf, (FcChar32 *) ctx->in);
137
138	/* Now fill the next block with 56 bytes */
139	memset(ctx->in, 0, 56);
140    } else {
141	/* Pad block to 56 bytes */
142	memset(p, 0, count - 8);
143    }
144    byteReverse(ctx->in, 14);
145
146    /* Append length in bits and transform */
147    ((FcChar32 *) ctx->in)[14] = ctx->bits[0];
148    ((FcChar32 *) ctx->in)[15] = ctx->bits[1];
149
150    MD5Transform(ctx->buf, (FcChar32 *) ctx->in);
151    byteReverse((unsigned char *) ctx->buf, 4);
152    memcpy(digest, ctx->buf, 16);
153    memset(ctx, 0, sizeof(*ctx));        /* In case it's sensitive */
154}
155
156
157/* The four core functions - F1 is optimized somewhat */
158
159/* #define F1(x, y, z) (x & y | ~x & z) */
160#define F1(x, y, z) (z ^ (x & (y ^ z)))
161#define F2(x, y, z) F1(z, x, y)
162#define F3(x, y, z) (x ^ y ^ z)
163#define F4(x, y, z) (y ^ (x | ~z))
164
165/* This is the central step in the MD5 algorithm. */
166#define MD5STEP(f, w, x, y, z, data, s) \
167	( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
168
169/*
170 * The core of the MD5 algorithm, this alters an existing MD5 hash to
171 * reflect the addition of 16 longwords of new data.  MD5Update blocks
172 * the data and converts bytes into longwords for this routine.
173 */
174static void MD5Transform(FcChar32 buf[4], FcChar32 in[16])
175{
176    register FcChar32 a, b, c, d;
177
178    a = buf[0];
179    b = buf[1];
180    c = buf[2];
181    d = buf[3];
182
183    MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
184    MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
185    MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
186    MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
187    MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
188    MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
189    MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
190    MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
191    MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
192    MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
193    MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
194    MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
195    MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
196    MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
197    MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
198    MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
199
200    MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
201    MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
202    MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
203    MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
204    MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
205    MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
206    MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
207    MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
208    MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
209    MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
210    MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
211    MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
212    MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
213    MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
214    MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
215    MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
216
217    MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
218    MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
219    MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
220    MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
221    MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
222    MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
223    MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
224    MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
225    MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
226    MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
227    MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
228    MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
229    MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
230    MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
231    MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
232    MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
233
234    MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
235    MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
236    MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
237    MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
238    MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
239    MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
240    MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
241    MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
242    MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
243    MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
244    MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
245    MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
246    MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
247    MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
248    MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
249    MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
250
251    buf[0] += a;
252    buf[1] += b;
253    buf[2] += c;
254    buf[3] += d;
255}
256