mdw@git.distorted.org.uk Git - secnet/blob - md5.c

   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  * [I interpet this as a blanket permision -iwj.]
   7  *
   8  * Equivalent code is available from RSA Data Security, Inc.
   9  * This code has been tested against that, and is equivalent,
  10  * except that you don't need to include two pages of legalese
  11  * with every copy.
  12  *
  13  * To compute the message digest of a chunk of bytes, declare an
  14  * MD5Context structure, pass it to MD5Init, call MD5Update as
  15  * needed on buffers full of bytes, and then call MD5Final, which
  16  * will fill a supplied 16-byte array with the digest.
  17  *
  18  * Changed so as no longer to depend on Colin Plumb's `usual.h' header
  19  * definitions; now uses stuff from dpkg's config.h.
  20  *  - Ian Jackson <ijackson@nyx.cs.du.edu>.
  21  * Still in the public domain.
  22  */
  23
  24 #include "secnet.h"
  25 #include <string.h>             /* for memcpy() */
  26 #include "md5.h"
  27
  28 #ifdef WORDS_BIGENDIAN
  29 static void
  30 byteSwap(uint32_t *buf, int words)
  31 {
  32         md5byte *p = (md5byte *)buf;
  33
  34         do {
  35                 *buf++ = (uint32_t)((unsigned)p[3] << 8 | p[2]) << 16 |
  36                         ((unsigned)p[1] << 8 | p[0]);
  37                 p += 4;
  38         } while (--words);
  39 }
  40 #else
  41 #define byteSwap(buf,words)
  42 #endif
  43
  44 /*
  45  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
  46  * initialization constants.
  47  */
  48 static void
  49 MD5Init(struct MD5Context *ctx)
  50 {
  51         ctx->buf[0] = 0x67452301;
  52         ctx->buf[1] = 0xefcdab89;
  53         ctx->buf[2] = 0x98badcfe;
  54         ctx->buf[3] = 0x10325476;
  55
  56         ctx->bytes[0] = 0;
  57         ctx->bytes[1] = 0;
  58 }
  59
  60 /*
  61  * Update context to reflect the concatenation of another buffer full
  62  * of bytes.
  63  */
  64 static void
  65 MD5Update(struct MD5Context *ctx, md5byte const *buf, unsigned len)
  66 {
  67         uint32_t t;
  68
  69         /* Update byte count */
  70
  71         t = ctx->bytes[0];
  72         if ((ctx->bytes[0] = t + len) < t)
  73                 ctx->bytes[1]++;        /* Carry from low to high */
  74
  75         t = 64 - (t & 0x3f);    /* Space available in ctx->in (at least 1) */
  76         if (t > len) {
  77                 memcpy((md5byte *)ctx->in + 64 - t, buf, len);
  78                 return;
  79         }
  80         /* First chunk is an odd size */
  81         memcpy((md5byte *)ctx->in + 64 - t, buf, t);
  82         byteSwap(ctx->in, 16);
  83         MD5Transform(ctx->buf, ctx->in);
  84         buf += t;
  85         len -= t;
  86
  87         /* Process data in 64-byte chunks */
  88         while (len >= 64) {
  89                 memcpy(ctx->in, buf, 64);
  90                 byteSwap(ctx->in, 16);
  91                 MD5Transform(ctx->buf, ctx->in);
  92                 buf += 64;
  93                 len -= 64;
  94         }
  95
  96         /* Handle any remaining bytes of data. */
  97         memcpy(ctx->in, buf, len);
  98 }
  99
 100 /*
 101  * Final wrapup - pad to 64-byte boundary with the bit pattern
 102  * 1 0* (64-bit count of bits processed, MSB-first)
 103  */
 104 static void
 105 MD5Final(md5byte digest[16], struct MD5Context *ctx)
 106 {
 107         int count = ctx->bytes[0] & 0x3f;       /* Number of bytes in ctx->in */
 108         md5byte *p = (md5byte *)ctx->in + count;
 109
 110         /* Set the first char of padding to 0x80.  There is always room. */
 111         *p++ = 0x80;
 112
 113         /* Bytes of padding needed to make 56 bytes (-8..55) */
 114         count = 56 - 1 - count;
 115
 116         if (count < 0) {        /* Padding forces an extra block */
 117                 memset(p, 0, count + 8);
 118                 byteSwap(ctx->in, 16);
 119                 MD5Transform(ctx->buf, ctx->in);
 120                 p = (md5byte *)ctx->in;
 121                 count = 56;
 122         }
 123         memset(p, 0, count);
 124         byteSwap(ctx->in, 14);
 125
 126         /* Append length in bits and transform */
 127         ctx->in[14] = ctx->bytes[0] << 3;
 128         ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
 129         MD5Transform(ctx->buf, ctx->in);
 130
 131         byteSwap(ctx->buf, 4);
 132         memcpy(digest, ctx->buf, 16);
 133         memset(ctx, 0, sizeof *ctx);    /* In case it's sensitive */
 134 }
 135
 136 #ifndef ASM_MD5
 137
 138 /* The four core functions - F1 is optimized somewhat */
 139
 140 /* #define F1(x, y, z) (x & y | ~x & z) */
 141 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 142 #define F2(x, y, z) F1(z, x, y)
 143 #define F3(x, y, z) (x ^ y ^ z)
 144 #define F4(x, y, z) (y ^ (x | ~z))
 145
 146 /* This is the central step in the MD5 algorithm. */
 147 #define MD5STEP(f,w,x,y,z,in,s) \
 148          (w += f(x,y,z) + in, w = (w<<s | w>>(32-s)) + x)
 149
 150 /*
 151  * The core of the MD5 algorithm, this alters an existing MD5 hash to
 152  * reflect the addition of 16 longwords of new data.  MD5Update blocks
 153  * the data and converts bytes into longwords for this routine.
 154  */
 155 static void
 156 MD5Transform(uint32_t buf[4], uint32_t const in[16])
 157 {
 158         register uint32_t a, b, c, d;
 159
 160         a = buf[0];
 161         b = buf[1];
 162         c = buf[2];
 163         d = buf[3];
 164
 165         MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
 166         MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
 167         MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
 168         MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
 169         MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
 170         MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
 171         MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
 172         MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
 173         MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
 174         MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
 175         MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
 176         MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
 177         MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
 178         MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
 179         MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
 180         MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
 181
 182         MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
 183         MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
 184         MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
 185         MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
 186         MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
 187         MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
 188         MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
 189         MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
 190         MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
 191         MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
 192         MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
 193         MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
 194         MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
 195         MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
 196         MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
 197         MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 198
 199         MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
 200         MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
 201         MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
 202         MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
 203         MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
 204         MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
 205         MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
 206         MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
 207         MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
 208         MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
 209         MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
 210         MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
 211         MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
 212         MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
 213         MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
 214         MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 215
 216         MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
 217         MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
 218         MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
 219         MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
 220         MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
 221         MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
 222         MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
 223         MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
 224         MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
 225         MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
 226         MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
 227         MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
 228         MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
 229         MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
 230         MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
 231         MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 232
 233         buf[0] += a;
 234         buf[1] += b;
 235         buf[2] += c;
 236         buf[3] += d;
 237 }
 238
 239 #endif
 240
 241 static void *md5_init(void)
 242 {
 243     struct MD5Context *ctx;
 244
 245     NEW(ctx);
 246     MD5Init(ctx);
 247
 248     return ctx;
 249 }
 250
 251 static void md5_update(void *sst, const void *buf, int32_t len)
 252 {
 253     struct MD5Context *ctx=sst;
 254
 255     MD5Update(ctx,buf,len);
 256 }
 257
 258 static void md5_final(void *sst, uint8_t *digest)
 259 {
 260     struct MD5Context *ctx=sst;
 261
 262     MD5Final(digest,ctx);
 263     free(ctx);
 264 }
 265
 266 struct md5 {
 267     closure_t cl;
 268     struct hash_if ops;
 269 };
 270
 271 void md5_module(dict_t *dict)
 272 {
 273     struct md5 *st;
 274     void *ctx;
 275     cstring_t testinput="12345\n";
 276     uint8_t expected[16]=
 277         {0xd5,0x77,0x27,0x3f,0xf8,0x85,0xc3,0xf8,
 278          0x4d,0xad,0xb8,0x57,0x8b,0xb4,0x13,0x99};
 279     uint8_t digest[16];
 280     int i;
 281
 282     NEW(st);
 283     st->cl.description="md5";
 284     st->cl.type=CL_HASH;
 285     st->cl.apply=NULL;
 286     st->cl.interface=&st->ops;
 287     st->ops.len=16;
 288     st->ops.init=md5_init;
 289     st->ops.update=md5_update;
 290     st->ops.final=md5_final;
 291
 292     dict_add(dict,"md5",new_closure(&st->cl));
 293
 294     ctx=md5_init();
 295     md5_update(ctx,testinput,strlen(testinput));
 296     md5_final(ctx,digest);
 297     for (i=0; i<16; i++) {
 298         if (digest[i]!=expected[i]) {
 299             fatal("md5 module failed self-test");
 300         }
 301     }
 302 }