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
27static void byteSwap(UWORD32 *buf, unsigned words) {
28  md5byte *p;
29
30  /* Only swap bytes for big endian machines */
31  int i = 1;
32
33  if (*(char *)&i == 1) return;
34
35  p = (md5byte *)buf;
36
37  do {
38    *buf++ = (UWORD32)((unsigned)p[3] << 8 | p[2]) << 16 |
39             ((unsigned)p[1] << 8 | p[0]);
40    p += 4;
41  } while (--words);
42}
43
44/*
45 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
46 * initialization constants.
47 */
48void MD5Init(struct MD5Context *ctx) {
49  ctx->buf[0] = 0x67452301;
50  ctx->buf[1] = 0xefcdab89;
51  ctx->buf[2] = 0x98badcfe;
52  ctx->buf[3] = 0x10325476;
53
54  ctx->bytes[0] = 0;
55  ctx->bytes[1] = 0;
56}
57
58/*
59 * Update context to reflect the concatenation of another buffer full
60 * of bytes.
61 */
62void MD5Update(struct MD5Context *ctx, md5byte const *buf, unsigned len) {
63  UWORD32 t;
64
65  /* Update byte count */
66
67  t = ctx->bytes[0];
68
69  if ((ctx->bytes[0] = t + len) < t)
70    ctx->bytes[1]++; /* Carry from low to high */
71
72  t = 64 - (t & 0x3f); /* Space available in ctx->in (at least 1) */
73
74  if (t > len) {
75    memcpy((md5byte *)ctx->in + 64 - t, buf, len);
76    return;
77  }
78
79  /* First chunk is an odd size */
80  memcpy((md5byte *)ctx->in + 64 - t, buf, t);
81  byteSwap(ctx->in, 16);
82  MD5Transform(ctx->buf, ctx->in);
83  buf += t;
84  len -= t;
85
86  /* Process data in 64-byte chunks */
87  while (len >= 64) {
88    memcpy(ctx->in, buf, 64);
89    byteSwap(ctx->in, 16);
90    MD5Transform(ctx->buf, ctx->in);
91    buf += 64;
92    len -= 64;
93  }
94
95  /* Handle any remaining bytes of data. */
96  memcpy(ctx->in, buf, len);
97}
98
99/*
100 * Final wrapup - pad to 64-byte boundary with the bit pattern
101 * 1 0* (64-bit count of bits processed, MSB-first)
102 */
103void MD5Final(md5byte digest[16], struct MD5Context *ctx) {
104  int count = ctx->bytes[0] & 0x3f; /* Number of bytes in ctx->in */
105  md5byte *p = (md5byte *)ctx->in + count;
106
107  /* Set the first char of padding to 0x80.  There is always room. */
108  *p++ = 0x80;
109
110  /* Bytes of padding needed to make 56 bytes (-8..55) */
111  count = 56 - 1 - count;
112
113  if (count < 0) { /* Padding forces an extra block */
114    memset(p, 0, count + 8);
115    byteSwap(ctx->in, 16);
116    MD5Transform(ctx->buf, ctx->in);
117    p = (md5byte *)ctx->in;
118    count = 56;
119  }
120
121  memset(p, 0, count);
122  byteSwap(ctx->in, 14);
123
124  /* Append length in bits and transform */
125  ctx->in[14] = ctx->bytes[0] << 3;
126  ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
127  MD5Transform(ctx->buf, ctx->in);
128
129  byteSwap(ctx->buf, 4);
130  memcpy(digest, ctx->buf, 16);
131  memset(ctx, 0, sizeof(*ctx)); /* In case it's sensitive */
132}
133
134#ifndef ASM_MD5
135
136/* The four core functions - F1 is optimized somewhat */
137
138/* #define F1(x, y, z) (x & y | ~x & z) */
139#define F1(x, y, z) (z ^ (x & (y ^ z)))
140#define F2(x, y, z) F1(z, x, y)
141#define F3(x, y, z) (x ^ y ^ z)
142#define F4(x, y, z) (y ^ (x | ~z))
143
144/* This is the central step in the MD5 algorithm. */
145#define MD5STEP(f, w, x, y, z, in, s) \
146  (w += f(x, y, z) + in, w = (w << s | w >> (32 - s)) + x)
147
148#if defined(__clang__) && defined(__has_attribute)
149#if __has_attribute(no_sanitize)
150#define VPX_NO_UNSIGNED_OVERFLOW_CHECK \
151  __attribute__((no_sanitize("unsigned-integer-overflow")))
152#endif
153#endif
154
155#ifndef VPX_NO_UNSIGNED_OVERFLOW_CHECK
156#define VPX_NO_UNSIGNED_OVERFLOW_CHECK
157#endif
158
159/*
160 * The core of the MD5 algorithm, this alters an existing MD5 hash to
161 * reflect the addition of 16 longwords of new data.  MD5Update blocks
162 * the data and converts bytes into longwords for this routine.
163 */
164VPX_NO_UNSIGNED_OVERFLOW_CHECK void MD5Transform(UWORD32 buf[4],
165                                                 UWORD32 const in[16]) {
166  register UWORD32 a, b, c, d;
167
168  a = buf[0];
169  b = buf[1];
170  c = buf[2];
171  d = buf[3];
172
173  MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
174  MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
175  MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
176  MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
177  MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
178  MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
179  MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
180  MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
181  MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
182  MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
183  MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
184  MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
185  MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
186  MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
187  MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
188  MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
189
190  MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
191  MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
192  MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
193  MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
194  MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
195  MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
196  MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
197  MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
198  MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
199  MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
200  MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
201  MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
202  MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
203  MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
204  MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
205  MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
206
207  MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
208  MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
209  MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
210  MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
211  MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
212  MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
213  MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
214  MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
215  MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
216  MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
217  MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
218  MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
219  MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
220  MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
221  MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
222  MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
223
224  MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
225  MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
226  MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
227  MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
228  MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
229  MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
230  MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
231  MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
232  MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
233  MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
234  MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
235  MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
236  MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
237  MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
238  MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
239  MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
240
241  buf[0] += a;
242  buf[1] += b;
243  buf[2] += c;
244  buf[3] += d;
245}
246
247#undef VPX_NO_UNSIGNED_OVERFLOW_CHECK
248
249#endif
250