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 /* Minor tweaks for use from Omega:
19 *
20 * + Use WORDS_BIGENDIAN (probed by autoconf) to check endianness.
21 * + uint32 -> uint32_t (as defined by netinet/in.h).
22 * + Internal functions are now static.
23 * + Fix sizeof(ctx) to sizeof(*ctx) (bug picked up by Stanford checker on
24 * this code incorporated into the Linux kernel).
25 * + Renamed to .cc and compiled as C++.
26 * + Changed MD5Context.in to uint32_t instead of unsigned char, and
27 * byteReverse to take "uint32_t *" instead of "unsigned char *".
28 */
29
30 #include <config.h>
31
32 #include <cstring> /* for memcpy() */
33 #include "md5.h"
34
35 using namespace std;
36
37 #ifndef WORDS_BIGENDIAN
38 #define byteReverse(buf, len) /* Nothing */
39 #else
40 static void byteReverse(uint32_t *buf, unsigned longs);
41
42 #ifndef ASM_MD5
43 /*
44 * Note: this code is harmless on little-endian machines.
45 */
byteReverse(uint32_t * buf,unsigned longs)46 static void byteReverse(uint32_t *buf, unsigned longs)
47 {
48 uint32_t t;
49 do {
50 unsigned char * p = (unsigned char *)buf;
51 t = (uint32_t) ((unsigned) p[3] << 8 | p[2]) << 16 |
52 ((unsigned) p[1] << 8 | p[0]);
53 *buf++ = t;
54 } while (--longs);
55 }
56 #endif
57 #endif
58
59 static void MD5Transform(uint32_t buf[4], uint32_t const in[16]);
60
61 /*
62 * Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
63 * initialization constants.
64 */
MD5Init(struct MD5Context * ctx)65 void MD5Init(struct MD5Context *ctx)
66 {
67 ctx->buf[0] = 0x67452301;
68 ctx->buf[1] = 0xefcdab89;
69 ctx->buf[2] = 0x98badcfe;
70 ctx->buf[3] = 0x10325476;
71
72 ctx->bits[0] = 0;
73 ctx->bits[1] = 0;
74 }
75
76 /*
77 * Update context to reflect the concatenation of another buffer full
78 * of bytes.
79 */
MD5Update(struct MD5Context * ctx,unsigned char const * buf,unsigned len)80 void MD5Update(struct MD5Context *ctx, unsigned char const *buf, unsigned len)
81 {
82 uint32_t t;
83
84 /* Update bitcount */
85
86 t = ctx->bits[0];
87 if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t)
88 ctx->bits[1]++; /* Carry from low to high */
89 ctx->bits[1] += len >> 29;
90
91 t = (t >> 3) & 0x3f; /* Bytes already in shsInfo->data */
92
93 /* Handle any leading odd-sized chunks */
94
95 if (t) {
96 unsigned char *p = (unsigned char *) ctx->in + t;
97
98 t = 64 - t;
99 if (len < t) {
100 memcpy(p, buf, len);
101 return;
102 }
103 memcpy(p, buf, t);
104 byteReverse(ctx->in, 16);
105 MD5Transform(ctx->buf, ctx->in);
106 buf += t;
107 len -= t;
108 }
109 /* Process data in 64-byte chunks */
110
111 while (len >= 64) {
112 memcpy(ctx->in, buf, 64);
113 byteReverse(ctx->in, 16);
114 MD5Transform(ctx->buf, ctx->in);
115 buf += 64;
116 len -= 64;
117 }
118
119 /* Handle any remaining bytes of data. */
120
121 memcpy(ctx->in, buf, len);
122 }
123
124 /*
125 * Final wrapup - pad to 64-byte boundary with the bit pattern
126 * 1 0* (64-bit count of bits processed, MSB-first)
127 */
MD5Final(unsigned char digest[16],struct MD5Context * ctx)128 void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
129 {
130 unsigned count;
131 unsigned char *p;
132
133 /* Compute number of bytes mod 64 */
134 count = (ctx->bits[0] >> 3) & 0x3F;
135
136 /* Set the first char of padding to 0x80. This is safe since there is
137 always at least one byte free */
138 p = (unsigned char *)ctx->in + count;
139 *p++ = 0x80;
140
141 /* Bytes of padding needed to make 64 bytes */
142 count = 64 - 1 - count;
143
144 /* Pad out to 56 mod 64 */
145 if (count < 8) {
146 /* Two lots of padding: Pad the first block to 64 bytes */
147 memset(p, 0, count);
148 byteReverse(ctx->in, 16);
149 MD5Transform(ctx->buf, ctx->in);
150
151 /* Now fill the next block with 56 bytes */
152 memset(ctx->in, 0, 56);
153 } else {
154 /* Pad block to 56 bytes */
155 memset(p, 0, count - 8);
156 byteReverse(ctx->in, 14);
157 }
158
159 /* Append length in bits and transform */
160 ctx->in[14] = ctx->bits[0];
161 ctx->in[15] = ctx->bits[1];
162
163 MD5Transform(ctx->buf, ctx->in);
164 byteReverse(ctx->buf, 4);
165 memcpy(digest, ctx->buf, 16);
166 memset(ctx, 0, sizeof(*ctx)); /* In case it's sensitive */
167 }
168
169 #ifndef ASM_MD5
170
171 /* The four core functions - F1 is optimized somewhat */
172
173 /* #define F1(x, y, z) (x & y | ~x & z) */
174 #define F1(x, y, z) (z ^ (x & (y ^ z)))
175 #define F2(x, y, z) F1(z, x, y)
176 #define F3(x, y, z) (x ^ y ^ z)
177 #define F4(x, y, z) (y ^ (x | ~z))
178
179 /* This is the central step in the MD5 algorithm. */
180 #define MD5STEP(f, w, x, y, z, data, s) \
181 ( w += f(x, y, z) + data, w = w<<s | w>>(32-s), w += x )
182
183 /*
184 * The core of the MD5 algorithm, this alters an existing MD5 hash to
185 * reflect the addition of 16 longwords of new data. MD5Update blocks
186 * the data and converts bytes into longwords for this routine.
187 */
MD5Transform(uint32_t buf[4],uint32_t const in[16])188 static void MD5Transform(uint32_t buf[4], uint32_t const in[16])
189 {
190 uint32_t a, b, c, d;
191
192 a = buf[0];
193 b = buf[1];
194 c = buf[2];
195 d = buf[3];
196
197 MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
198 MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
199 MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
200 MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
201 MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
202 MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
203 MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
204 MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
205 MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
206 MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
207 MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
208 MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
209 MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
210 MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
211 MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
212 MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
213
214 MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
215 MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
216 MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
217 MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
218 MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
219 MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
220 MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
221 MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
222 MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
223 MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
224 MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
225 MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
226 MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
227 MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
228 MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
229 MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
230
231 MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
232 MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
233 MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
234 MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
235 MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
236 MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
237 MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
238 MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
239 MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
240 MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
241 MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
242 MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
243 MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
244 MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
245 MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
246 MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
247
248 MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
249 MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
250 MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
251 MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
252 MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
253 MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
254 MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
255 MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
256 MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
257 MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
258 MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
259 MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
260 MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
261 MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
262 MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
263 MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
264
265 buf[0] += a;
266 buf[1] += b;
267 buf[2] += c;
268 buf[3] += d;
269 }
270
271 #endif
272