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