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md5.c
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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 
18 /* This code slightly modified to fit into Samba by
19  abartlet@samba.org Jun 2001 */
20 
21 #include "md5.h"
22 
23 #include <string.h> /* for memmove */
24 
25 static void
26 MD5Transform (uint32 buf[4], uint32 const in[16]);
27 
28 /*
29  * Note: this code is harmless on little-endian machines.
30  */
31 static void
32 byteReverse (unsigned char *buf, unsigned longs)
33 {
34  uint32 t;
35  do
36  {
37  t = (uint32) ((unsigned) buf[3] << 8 | buf[2]) << 16
38  | ((unsigned) buf[1] << 8 | buf[0]);
39  *(uint32 *) buf = t;
40  buf += 4;
41  }
42  while (--longs);
43 }
44 
45 /*
46  * Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
47  * initialization constants.
48  */
49 void
50 MD5Init (struct MD5Context *ctx)
51 {
52  ctx->buf[0] = 0x67452301;
53  ctx->buf[1] = 0xefcdab89;
54  ctx->buf[2] = 0x98badcfe;
55  ctx->buf[3] = 0x10325476;
56 
57  ctx->bits[0] = 0;
58  ctx->bits[1] = 0;
59 }
60 
61 /*
62  * Update context to reflect the concatenation of another buffer full
63  * of bytes.
64  */
65 void
66 MD5Update (struct MD5Context *ctx, unsigned char const *buf, unsigned len)
67 {
68  register uint32 t;
69 
70  /* Update bitcount */
71 
72  t = ctx->bits[0];
73  if ((ctx->bits[0] = t + ((uint32) len << 3)) < t)
74  ctx->bits[1]++; /* Carry from low to high */
75  ctx->bits[1] += len >> 29;
76 
77  t = (t >> 3) & 0x3f; /* Bytes already in shsInfo->data */
78 
79  /* Handle any leading odd-sized chunks */
80 
81  if (t)
82  {
83  unsigned char *p = (unsigned char *) ctx->in + t;
84 
85  t = 64 - t;
86  if (len < t)
87  {
88  memmove (p, buf, len);
89  return;
90  }
91  memmove (p, buf, t);
92  byteReverse (ctx->in, 16);
93  MD5Transform (ctx->buf, (uint32 *) ctx->in);
94  buf += t;
95  len -= t;
96  }
97  /* Process data in 64-byte chunks */
98 
99  while (len >= 64)
100  {
101  memmove (ctx->in, buf, 64);
102  byteReverse (ctx->in, 16);
103  MD5Transform (ctx->buf, (uint32 *) ctx->in);
104  buf += 64;
105  len -= 64;
106  }
107 
108  /* Handle any remaining bytes of data. */
109 
110  memmove (ctx->in, buf, len);
111 }
112 
113 /*
114  * Final wrapup - pad to 64-byte boundary with the bit pattern
115  * 1 0* (64-bit count of bits processed, MSB-first)
116  */
117 void
118 MD5Final (unsigned char digest[16], struct MD5Context *ctx)
119 {
120  unsigned int count;
121  unsigned char *p;
122 
123  /* Compute number of bytes mod 64 */
124  count = (ctx->bits[0] >> 3) & 0x3F;
125 
126  /* Set the first char of padding to 0x80. This is safe since there is
127  always at least one byte free */
128  p = ctx->in + count;
129  *p++ = 0x80;
130 
131  /* Bytes of padding needed to make 64 bytes */
132  count = 64 - 1 - count;
133 
134  /* Pad out to 56 mod 64 */
135  if (count < 8)
136  {
137  /* Two lots of padding: Pad the first block to 64 bytes */
138  memset (p, 0, count);
139  byteReverse (ctx->in, 16);
140  MD5Transform (ctx->buf, (uint32 *) ctx->in);
141 
142  /* Now fill the next block with 56 bytes */
143  memset (ctx->in, 0, 56);
144  }
145  else
146  {
147  /* Pad block to 56 bytes */
148  memset (p, 0, count - 8);
149  }
150  byteReverse (ctx->in, 14);
151 
152  /* Append length in bits and transform */
153  ((uint32 *) ctx->in)[14] = ctx->bits[0];
154  ((uint32 *) ctx->in)[15] = ctx->bits[1];
155 
156  MD5Transform (ctx->buf, (uint32 *) ctx->in);
157  byteReverse ((unsigned char *) ctx->buf, 4);
158  memmove (digest, ctx->buf, 16);
159  memset (ctx, 0, sizeof (*ctx)); /* In case it's sensitive */
160 }
161 
162 /* The four core functions - F1 is optimized somewhat */
163 
164 /* #define F1(x, y, z) (x & y | ~x & z) */
165 #define F1(x, y, z) (z ^ (x & (y ^ z)))
166 #define F2(x, y, z) F1 (z, x, y)
167 #define F3(x, y, z) (x ^ y ^ z)
168 #define F4(x, y, z) (y ^ (x | ~z))
169 
170 /* This is the central step in the MD5 algorithm. */
171 #define MD5STEP(f, w, x, y, z, data, s) \
172  (w += f (x, y, z) + data, w = w << s | w >> (32 - s), w += x)
173 
174 /*
175  * The core of the MD5 algorithm, this alters an existing MD5 hash to
176  * reflect the addition of 16 longwords of new data. MD5Update blocks
177  * the data and converts bytes into longwords for this routine.
178  */
179 static void
180 MD5Transform (uint32 buf[4], uint32 const in[16])
181 {
182  register uint32 a, b, c, d;
183 
184  a = buf[0];
185  b = buf[1];
186  c = buf[2];
187  d = buf[3];
188 
189  MD5STEP (F1, a, b, c, d, in[0] + 0xd76aa478, 7);
190  MD5STEP (F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
191  MD5STEP (F1, c, d, a, b, in[2] + 0x242070db, 17);
192  MD5STEP (F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
193  MD5STEP (F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
194  MD5STEP (F1, d, a, b, c, in[5] + 0x4787c62a, 12);
195  MD5STEP (F1, c, d, a, b, in[6] + 0xa8304613, 17);
196  MD5STEP (F1, b, c, d, a, in[7] + 0xfd469501, 22);
197  MD5STEP (F1, a, b, c, d, in[8] + 0x698098d8, 7);
198  MD5STEP (F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
199  MD5STEP (F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
200  MD5STEP (F1, b, c, d, a, in[11] + 0x895cd7be, 22);
201  MD5STEP (F1, a, b, c, d, in[12] + 0x6b901122, 7);
202  MD5STEP (F1, d, a, b, c, in[13] + 0xfd987193, 12);
203  MD5STEP (F1, c, d, a, b, in[14] + 0xa679438e, 17);
204  MD5STEP (F1, b, c, d, a, in[15] + 0x49b40821, 22);
205 
206  MD5STEP (F2, a, b, c, d, in[1] + 0xf61e2562, 5);
207  MD5STEP (F2, d, a, b, c, in[6] + 0xc040b340, 9);
208  MD5STEP (F2, c, d, a, b, in[11] + 0x265e5a51, 14);
209  MD5STEP (F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
210  MD5STEP (F2, a, b, c, d, in[5] + 0xd62f105d, 5);
211  MD5STEP (F2, d, a, b, c, in[10] + 0x02441453, 9);
212  MD5STEP (F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
213  MD5STEP (F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
214  MD5STEP (F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
215  MD5STEP (F2, d, a, b, c, in[14] + 0xc33707d6, 9);
216  MD5STEP (F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
217  MD5STEP (F2, b, c, d, a, in[8] + 0x455a14ed, 20);
218  MD5STEP (F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
219  MD5STEP (F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
220  MD5STEP (F2, c, d, a, b, in[7] + 0x676f02d9, 14);
221  MD5STEP (F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
222 
223  MD5STEP (F3, a, b, c, d, in[5] + 0xfffa3942, 4);
224  MD5STEP (F3, d, a, b, c, in[8] + 0x8771f681, 11);
225  MD5STEP (F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
226  MD5STEP (F3, b, c, d, a, in[14] + 0xfde5380c, 23);
227  MD5STEP (F3, a, b, c, d, in[1] + 0xa4beea44, 4);
228  MD5STEP (F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
229  MD5STEP (F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
230  MD5STEP (F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
231  MD5STEP (F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
232  MD5STEP (F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
233  MD5STEP (F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
234  MD5STEP (F3, b, c, d, a, in[6] + 0x04881d05, 23);
235  MD5STEP (F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
236  MD5STEP (F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
237  MD5STEP (F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
238  MD5STEP (F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
239 
240  MD5STEP (F4, a, b, c, d, in[0] + 0xf4292244, 6);
241  MD5STEP (F4, d, a, b, c, in[7] + 0x432aff97, 10);
242  MD5STEP (F4, c, d, a, b, in[14] + 0xab9423a7, 15);
243  MD5STEP (F4, b, c, d, a, in[5] + 0xfc93a039, 21);
244  MD5STEP (F4, a, b, c, d, in[12] + 0x655b59c3, 6);
245  MD5STEP (F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
246  MD5STEP (F4, c, d, a, b, in[10] + 0xffeff47d, 15);
247  MD5STEP (F4, b, c, d, a, in[1] + 0x85845dd1, 21);
248  MD5STEP (F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
249  MD5STEP (F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
250  MD5STEP (F4, c, d, a, b, in[6] + 0xa3014314, 15);
251  MD5STEP (F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
252  MD5STEP (F4, a, b, c, d, in[4] + 0xf7537e82, 6);
253  MD5STEP (F4, d, a, b, c, in[11] + 0xbd3af235, 10);
254  MD5STEP (F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
255  MD5STEP (F4, b, c, d, a, in[9] + 0xeb86d391, 21);
256 
257  buf[0] += a;
258  buf[1] += b;
259  buf[2] += c;
260  buf[3] += d;
261 }
#define uint32
Definition: genrand.c:54
unsigned char in[64]
Definition: md5.h:50
#define F2(x, y, z)
Definition: md5.c:166
#define F1(x, y, z)
Definition: md5.c:165
uint32 buf[4]
Definition: md5.h:48
uint32 bits[2]
Definition: md5.h:49
static void byteReverse(unsigned char *buf, unsigned longs)
Definition: md5.c:32
#define MD5STEP(f, w, x, y, z, data, s)
Definition: md5.c:171
#define F3(x, y, z)
Definition: md5.c:167
static void MD5Transform(uint32 buf[4], uint32 const in[16])
Definition: md5.c:180
#define F4(x, y, z)
Definition: md5.c:168
void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
Definition: md5.c:118
void MD5Init(struct MD5Context *ctx)
Definition: md5.c:50
Definition: md5.h:46
void MD5Update(struct MD5Context *ctx, unsigned char const *buf, unsigned len)
Definition: md5.c:66