1 /*
2 * written by Colin Plumb in 1993, no copyright is claimed.
3 * This code is in the public domain; do with it what you wish.
4 *
5 * Equivalent code is available from RSA Data Security, Inc.
6 * This code has been tested against that, and is equivalent,
7 * except that you don't need to include two pages of legalese
8 * with every copy.
9 *
10 * To compute the message digest of a chunk of bytes, declare an
11 * MD5Context structure, pass it to MD5Init, call MD5Update as
12 * needed on buffers full of bytes, and then call MD5Final, which
13 * will fill a supplied 16-byte array with the digest.
14 */
15
16 #ifdef HAVE_CONFIG_H
17 #include <config.h> // Must come first
18 #endif
19
20 #include <string.h>
21
22 #include "common/md5.h"
23
24 namespace google_breakpad {
25
26 #ifndef WORDS_BIGENDIAN
27 #define byteReverse(buf, len) /* Nothing */
28 #else
29 /*
30 * Note: this code is harmless on little-endian machines.
31 */
32 static void byteReverse(unsigned char *buf, unsigned longs)
33 {
34 u32 t;
35 do {
36 t = (u32) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
37 ((unsigned) buf[1] << 8 | buf[0]);
38 *(u32*) buf = t;
39 buf += 4;
40 } while (--longs);
41 }
42 #endif
43
44 static void MD5Transform(u32 buf[4], u32 const in[16]);
45
46 /*
47 * Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
48 * initialization constants.
49 */
MD5Init(struct MD5Context * ctx)50 void 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 */
MD5Update(struct MD5Context * ctx,unsigned char const * buf,size_t len)65 void MD5Update(struct MD5Context *ctx, unsigned char const *buf, size_t len)
66 {
67 u32 t;
68
69 /* Update bitcount */
70
71 t = ctx->bits[0];
72 if ((ctx->bits[0] = t + ((u32) len << 3)) < t)
73 ctx->bits[1]++; /* Carry from low to high */
74 ctx->bits[1] += len >> 29;
75
76 t = (t >> 3) & 0x3f; /* Bytes already in shsInfo->data */
77
78 /* Handle any leading odd-sized chunks */
79
80 if (t) {
81 unsigned char *p = (unsigned char*) ctx->in + t;
82
83 t = 64 - t;
84 if (len < t) {
85 memcpy(p, buf, len);
86 return;
87 }
88 memcpy(p, buf, t);
89 byteReverse(ctx->in, 16);
90 MD5Transform(ctx->buf, (u32*) ctx->in);
91 buf += t;
92 len -= t;
93 }
94 /* Process data in 64-byte chunks */
95
96 while (len >= 64) {
97 memcpy(ctx->in, buf, 64);
98 byteReverse(ctx->in, 16);
99 MD5Transform(ctx->buf, (u32*) ctx->in);
100 buf += 64;
101 len -= 64;
102 }
103
104 /* Handle any remaining bytes of data. */
105
106 memcpy(ctx->in, buf, len);
107 }
108
109 /*
110 * Final wrapup - pad to 64-byte boundary with the bit pattern
111 * 1 0* (64-bit count of bits processed, MSB-first)
112 */
MD5Final(unsigned char digest[16],struct MD5Context * ctx)113 void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
114 {
115 unsigned count;
116 unsigned char *p;
117
118 /* Compute number of bytes mod 64 */
119 count = (ctx->bits[0] >> 3) & 0x3F;
120
121 /* Set the first char of padding to 0x80. This is safe since there is
122 always at least one byte free */
123 p = ctx->in + count;
124 *p++ = 0x80;
125
126 /* Bytes of padding needed to make 64 bytes */
127 count = 64 - 1 - count;
128
129 /* Pad out to 56 mod 64 */
130 if (count < 8) {
131 /* Two lots of padding: Pad the first block to 64 bytes */
132 memset(p, 0, count);
133 byteReverse(ctx->in, 16);
134 MD5Transform(ctx->buf, (u32*) ctx->in);
135
136 /* Now fill the next block with 56 bytes */
137 memset(ctx->in, 0, 56);
138 } else {
139 /* Pad block to 56 bytes */
140 memset(p, 0, count - 8);
141 }
142 byteReverse(ctx->in, 14);
143
144 /* Append length in bits and transform */
145 memcpy(&ctx->in[14], &ctx->bits[0], sizeof(u32));
146 memcpy(&ctx->in[15], &ctx->bits[1], sizeof(u32));
147
148 MD5Transform(ctx->buf, (u32*) ctx->in);
149 byteReverse((unsigned char*) ctx->buf, 4);
150 memcpy(digest, ctx->buf, 16);
151 memset(ctx, 0, sizeof(*ctx)); /* In case it's sensitive */
152 }
153
154 /* The four core functions - F1 is optimized somewhat */
155
156 /* #define F1(x, y, z) (x & y | ~x & z) */
157 #define F1(x, y, z) (z ^ (x & (y ^ z)))
158 #define F2(x, y, z) F1(z, x, y)
159 #define F3(x, y, z) (x ^ y ^ z)
160 #define F4(x, y, z) (y ^ (x | ~z))
161
162 /* This is the central step in the MD5 algorithm. */
163 #define MD5STEP(f, w, x, y, z, data, s) \
164 ( w += f(x, y, z) + data, w = w<<s | w>>(32-s), w += x )
165
166 /*
167 * The core of the MD5 algorithm, this alters an existing MD5 hash to
168 * reflect the addition of 16 longwords of new data. MD5Update blocks
169 * the data and converts bytes into longwords for this routine.
170 */
MD5Transform(u32 buf[4],u32 const in[16])171 static void MD5Transform(u32 buf[4], u32 const in[16])
172 {
173 u32 a, b, c, d;
174
175 a = buf[0];
176 b = buf[1];
177 c = buf[2];
178 d = buf[3];
179
180 MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
181 MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
182 MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
183 MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
184 MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
185 MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
186 MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
187 MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
188 MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
189 MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
190 MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
191 MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
192 MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
193 MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
194 MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
195 MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
196
197 MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
198 MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
199 MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
200 MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
201 MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
202 MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
203 MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
204 MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
205 MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
206 MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
207 MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
208 MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
209 MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
210 MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
211 MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
212 MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
213
214 MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
215 MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
216 MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
217 MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
218 MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
219 MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
220 MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
221 MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
222 MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
223 MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
224 MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
225 MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
226 MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
227 MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
228 MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
229 MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
230
231 MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
232 MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
233 MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
234 MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
235 MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
236 MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
237 MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
238 MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
239 MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
240 MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
241 MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
242 MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
243 MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
244 MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
245 MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
246 MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
247
248 buf[0] += a;
249 buf[1] += b;
250 buf[2] += c;
251 buf[3] += d;
252 }
253
254 } // namespace google_breakpad
255
256