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