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 #include <string.h>
17
18 #include "common/md5.h"
19
20 namespace google_breakpad {
21
22 #ifndef WORDS_BIGENDIAN
23 #define byteReverse(buf, len) /* Nothing */
24 #else
25 /*
26 * Note: this code is harmless on little-endian machines.
27 */
28 static void byteReverse(unsigned char *buf, unsigned longs)
29 {
30 u32 t;
31 do {
32 t = (u32) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
33 ((unsigned) buf[1] << 8 | buf[0]);
34 *(u32 *) buf = t;
35 buf += 4;
36 } while (--longs);
37 }
38 #endif
39
40 static void MD5Transform(u32 buf[4], u32 const in[16]);
41
42 /*
43 * Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
44 * initialization constants.
45 */
MD5Init(struct MD5Context * ctx)46 void MD5Init(struct MD5Context *ctx)
47 {
48 ctx->buf[0] = 0x67452301;
49 ctx->buf[1] = 0xefcdab89;
50 ctx->buf[2] = 0x98badcfe;
51 ctx->buf[3] = 0x10325476;
52
53 ctx->bits[0] = 0;
54 ctx->bits[1] = 0;
55 }
56
57 /*
58 * Update context to reflect the concatenation of another buffer full
59 * of bytes.
60 */
MD5Update(struct MD5Context * ctx,unsigned char const * buf,size_t len)61 void MD5Update(struct MD5Context *ctx, unsigned char const *buf, size_t len)
62 {
63 u32 t;
64
65 /* Update bitcount */
66
67 t = ctx->bits[0];
68 if ((ctx->bits[0] = t + ((u32) len << 3)) < t)
69 ctx->bits[1]++; /* Carry from low to high */
70 ctx->bits[1] += len >> 29;
71
72 t = (t >> 3) & 0x3f; /* Bytes already in shsInfo->data */
73
74 /* Handle any leading odd-sized chunks */
75
76 if (t) {
77 unsigned char *p = (unsigned char *) ctx->in + t;
78
79 t = 64 - t;
80 if (len < t) {
81 memcpy(p, buf, len);
82 return;
83 }
84 memcpy(p, buf, t);
85 byteReverse(ctx->in, 16);
86 MD5Transform(ctx->buf, (u32 *) ctx->in);
87 buf += t;
88 len -= t;
89 }
90 /* Process data in 64-byte chunks */
91
92 while (len >= 64) {
93 memcpy(ctx->in, buf, 64);
94 byteReverse(ctx->in, 16);
95 MD5Transform(ctx->buf, (u32 *) ctx->in);
96 buf += 64;
97 len -= 64;
98 }
99
100 /* Handle any remaining bytes of data. */
101
102 memcpy(ctx->in, buf, len);
103 }
104
105 /*
106 * Final wrapup - pad to 64-byte boundary with the bit pattern
107 * 1 0* (64-bit count of bits processed, MSB-first)
108 */
MD5Final(unsigned char digest[16],struct MD5Context * ctx)109 void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
110 {
111 unsigned count;
112 unsigned char *p;
113
114 /* Compute number of bytes mod 64 */
115 count = (ctx->bits[0] >> 3) & 0x3F;
116
117 /* Set the first char of padding to 0x80. This is safe since there is
118 always at least one byte free */
119 p = ctx->in + count;
120 *p++ = 0x80;
121
122 /* Bytes of padding needed to make 64 bytes */
123 count = 64 - 1 - count;
124
125 /* Pad out to 56 mod 64 */
126 if (count < 8) {
127 /* Two lots of padding: Pad the first block to 64 bytes */
128 memset(p, 0, count);
129 byteReverse(ctx->in, 16);
130 MD5Transform(ctx->buf, (u32 *) ctx->in);
131
132 /* Now fill the next block with 56 bytes */
133 memset(ctx->in, 0, 56);
134 } else {
135 /* Pad block to 56 bytes */
136 memset(p, 0, count - 8);
137 }
138 byteReverse(ctx->in, 14);
139
140 /* Append length in bits and transform */
141 ((u32 *) ctx->in)[14] = ctx->bits[0];
142 ((u32 *) ctx->in)[15] = ctx->bits[1];
143
144 MD5Transform(ctx->buf, (u32 *) ctx->in);
145 byteReverse((unsigned char *) ctx->buf, 4);
146 memcpy(digest, ctx->buf, 16);
147 memset(ctx, 0, sizeof(*ctx)); /* In case it's sensitive */
148 }
149
150 /* The four core functions - F1 is optimized somewhat */
151
152 /* #define F1(x, y, z) (x & y | ~x & z) */
153 #define F1(x, y, z) (z ^ (x & (y ^ z)))
154 #define F2(x, y, z) F1(z, x, y)
155 #define F3(x, y, z) (x ^ y ^ z)
156 #define F4(x, y, z) (y ^ (x | ~z))
157
158 /* This is the central step in the MD5 algorithm. */
159 #define MD5STEP(f, w, x, y, z, data, s) \
160 ( w += f(x, y, z) + data, w = w<<s | w>>(32-s), w += x )
161
162 /*
163 * The core of the MD5 algorithm, this alters an existing MD5 hash to
164 * reflect the addition of 16 longwords of new data. MD5Update blocks
165 * the data and converts bytes into longwords for this routine.
166 */
MD5Transform(u32 buf[4],u32 const in[16])167 static void MD5Transform(u32 buf[4], u32 const in[16])
168 {
169 u32 a, b, c, d;
170
171 a = buf[0];
172 b = buf[1];
173 c = buf[2];
174 d = buf[3];
175
176 MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
177 MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
178 MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
179 MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
180 MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
181 MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
182 MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
183 MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
184 MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
185 MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
186 MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
187 MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
188 MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
189 MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
190 MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
191 MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
192
193 MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
194 MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
195 MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
196 MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
197 MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
198 MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
199 MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
200 MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
201 MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
202 MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
203 MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
204 MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
205 MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
206 MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
207 MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
208 MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
209
210 MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
211 MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
212 MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
213 MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
214 MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
215 MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
216 MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
217 MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
218 MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
219 MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
220 MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
221 MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
222 MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
223 MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
224 MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
225 MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
226
227 MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
228 MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
229 MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
230 MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
231 MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
232 MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
233 MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
234 MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
235 MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
236 MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
237 MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
238 MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
239 MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
240 MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
241 MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
242 MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
243
244 buf[0] += a;
245 buf[1] += b;
246 buf[2] += c;
247 buf[3] += d;
248 }
249
250 } // namespace google_breakpad
251
252