src/src/auths/md5.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) University of Cambridge 1995 - 2018 */
   6 /* See the file NOTICE for conditions of use and distribution. */
   7
   8 #ifndef STAND_ALONE
   9 #include "../exim.h"
  10
  11 /* For stand-alone testing, we need to have the structure defined, and
  12 to be able to do I/O */
  13
  14 #else
  15 #include <stdio.h>
  16 #include "../mytypes.h"
  17 typedef struct md5 {
  18   unsigned int length;
  19   unsigned int abcd[4];
  20   }
  21 md5;
  22 #endif
  23
  24
  25
  26 /*************************************************
  27 *        Start off a new MD5 computation.        *
  28 *************************************************/
  29
  30 /*
  31 Argument:  pointer to md5 storage structure
  32 Returns:   nothing
  33 */
  34
  35 void
  36 md5_start(md5 *base)
  37 {
  38 base->abcd[0] = 0x67452301;
  39 base->abcd[1] = 0xefcdab89;
  40 base->abcd[2] = 0x98badcfe;
  41 base->abcd[3] = 0x10325476;
  42 base->length = 0;
  43 }
  44
  45
  46
  47 /*************************************************
  48 *       Process another 64-byte block            *
  49 *************************************************/
  50
  51 /* This function implements central part of the algorithm which is described
  52 in RFC 1321.
  53
  54 Arguments:
  55   base       pointer to md5 storage structure
  56   text       pointer to next 64 bytes of subject text
  57
  58 Returns:     nothing
  59 */
  60
  61 void
  62 md5_mid(md5 *base, const uschar *text)
  63 {
  64 register unsigned int a = base->abcd[0];
  65 register unsigned int b = base->abcd[1];
  66 register unsigned int c = base->abcd[2];
  67 register unsigned int d = base->abcd[3];
  68 unsigned int X[16];
  69 base->length += 64;
  70
  71 /* Load the 64 bytes into a set of working integers, treating them as 32-bit
  72 numbers in little-endian order. */
  73
  74 for (int i = 0; i < 16; i++)
  75   {
  76   X[i] = (unsigned int)(text[0]) |
  77          ((unsigned int)(text[1]) << 8) |
  78          ((unsigned int)(text[2]) << 16) |
  79          ((unsigned int)(text[3]) << 24);
  80   text += 4;
  81   }
  82
  83 /* For each round of processing there is a function to be applied. We define it
  84 as a macro each time round. */
  85
  86 /***********************************************
  87 *                    Round 1                   *
  88 *            F(X,Y,Z) = XY v not(X) Z          *
  89 * a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s) *
  90 ***********************************************/
  91
  92 #define OP(a, b, c, d, k, s, ti) \
  93      a += ((b & c) | (~b & d)) + X[k] + (unsigned int)ti; \
  94      a = b + ((a << s) | (a >> (32 - s)))
  95
  96 OP(a, b, c, d,  0,  7, 0xd76aa478);
  97 OP(d, a, b, c,  1, 12, 0xe8c7b756);
  98 OP(c, d, a, b,  2, 17, 0x242070db);
  99 OP(b, c, d, a,  3, 22, 0xc1bdceee);
 100 OP(a, b, c, d,  4,  7, 0xf57c0faf);
 101 OP(d, a, b, c,  5, 12, 0x4787c62a);
 102 OP(c, d, a, b,  6, 17, 0xa8304613);
 103 OP(b, c, d, a,  7, 22, 0xfd469501);
 104 OP(a, b, c, d,  8,  7, 0x698098d8);
 105 OP(d, a, b, c,  9, 12, 0x8b44f7af);
 106 OP(c, d, a, b, 10, 17, 0xffff5bb1);
 107 OP(b, c, d, a, 11, 22, 0x895cd7be);
 108 OP(a, b, c, d, 12,  7, 0x6b901122);
 109 OP(d, a, b, c, 13, 12, 0xfd987193);
 110 OP(c, d, a, b, 14, 17, 0xa679438e);
 111 OP(b, c, d, a, 15, 22, 0x49b40821);
 112
 113 #undef OP
 114
 115 /***********************************************
 116 *                    Round 2                   *
 117 *            F(X,Y,Z) = XZ v Y not(Z)          *
 118 * a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s) *
 119 ***********************************************/
 120
 121 #define OP(a, b, c, d, k, s, ti) \
 122      a += ((b & d) | (c & ~d)) + X[k] + (unsigned int)ti; \
 123      a = b + ((a << s) | (a >> (32 - s)))
 124
 125 OP(a, b, c, d,  1,  5, 0xf61e2562);
 126 OP(d, a, b, c,  6,  9, 0xc040b340);
 127 OP(c, d, a, b, 11, 14, 0x265e5a51);
 128 OP(b, c, d, a,  0, 20, 0xe9b6c7aa);
 129 OP(a, b, c, d,  5,  5, 0xd62f105d);
 130 OP(d, a, b, c, 10,  9, 0x02441453);
 131 OP(c, d, a, b, 15, 14, 0xd8a1e681);
 132 OP(b, c, d, a,  4, 20, 0xe7d3fbc8);
 133 OP(a, b, c, d,  9,  5, 0x21e1cde6);
 134 OP(d, a, b, c, 14,  9, 0xc33707d6);
 135 OP(c, d, a, b,  3, 14, 0xf4d50d87);
 136 OP(b, c, d, a,  8, 20, 0x455a14ed);
 137 OP(a, b, c, d, 13,  5, 0xa9e3e905);
 138 OP(d, a, b, c,  2,  9, 0xfcefa3f8);
 139 OP(c, d, a, b,  7, 14, 0x676f02d9);
 140 OP(b, c, d, a, 12, 20, 0x8d2a4c8a);
 141
 142 #undef OP
 143
 144 /***********************************************
 145 *                    Round 3                   *
 146 *            F(X,Y,Z) = X xor Y xor Z          *
 147 * a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s) *
 148 ***********************************************/
 149
 150 #define OP(a, b, c, d, k, s, ti) \
 151      a += (b ^ c ^ d) + X[k] + (unsigned int)ti; \
 152      a = b + ((a << s) | (a >> (32 - s)))
 153
 154 OP(a, b, c, d,  5,  4, 0xfffa3942);
 155 OP(d, a, b, c,  8, 11, 0x8771f681);
 156 OP(c, d, a, b, 11, 16, 0x6d9d6122);
 157 OP(b, c, d, a, 14, 23, 0xfde5380c);
 158 OP(a, b, c, d,  1,  4, 0xa4beea44);
 159 OP(d, a, b, c,  4, 11, 0x4bdecfa9);
 160 OP(c, d, a, b,  7, 16, 0xf6bb4b60);
 161 OP(b, c, d, a, 10, 23, 0xbebfbc70);
 162 OP(a, b, c, d, 13,  4, 0x289b7ec6);
 163 OP(d, a, b, c,  0, 11, 0xeaa127fa);
 164 OP(c, d, a, b,  3, 16, 0xd4ef3085);
 165 OP(b, c, d, a,  6, 23, 0x04881d05);
 166 OP(a, b, c, d,  9,  4, 0xd9d4d039);
 167 OP(d, a, b, c, 12, 11, 0xe6db99e5);
 168 OP(c, d, a, b, 15, 16, 0x1fa27cf8);
 169 OP(b, c, d, a,  2, 23, 0xc4ac5665);
 170
 171 #undef OP
 172
 173 /***********************************************
 174 *                    Round 4                   *
 175 *          F(X,Y,Z) = Y xor (X v not(Z))       *
 176 * a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s) *
 177 ***********************************************/
 178
 179 #define OP(a, b, c, d, k, s, ti) \
 180      a += (c ^ (b | ~d)) + X[k] + (unsigned int)ti; \
 181      a = b + ((a << s) | (a >> (32 - s)))
 182
 183 OP(a, b, c, d,  0,  6, 0xf4292244);
 184 OP(d, a, b, c,  7, 10, 0x432aff97);
 185 OP(c, d, a, b, 14, 15, 0xab9423a7);
 186 OP(b, c, d, a,  5, 21, 0xfc93a039);
 187 OP(a, b, c, d, 12,  6, 0x655b59c3);
 188 OP(d, a, b, c,  3, 10, 0x8f0ccc92);
 189 OP(c, d, a, b, 10, 15, 0xffeff47d);
 190 OP(b, c, d, a,  1, 21, 0x85845dd1);
 191 OP(a, b, c, d,  8,  6, 0x6fa87e4f);
 192 OP(d, a, b, c, 15, 10, 0xfe2ce6e0);
 193 OP(c, d, a, b,  6, 15, 0xa3014314);
 194 OP(b, c, d, a, 13, 21, 0x4e0811a1);
 195 OP(a, b, c, d,  4,  6, 0xf7537e82);
 196 OP(d, a, b, c, 11, 10, 0xbd3af235);
 197 OP(c, d, a, b,  2, 15, 0x2ad7d2bb);
 198 OP(b, c, d, a,  9, 21, 0xeb86d391);
 199
 200 #undef OP
 201
 202 /* Add the new values back into the accumulators. */
 203
 204 base->abcd[0] += a;
 205 base->abcd[1] += b;
 206 base->abcd[2] += c;
 207 base->abcd[3] += d;
 208 }
 209
 210
 211
 212
 213 /*************************************************
 214 *     Process the final text string              *
 215 *************************************************/
 216
 217 /* The string may be of any length. It is padded out according to the rules
 218 for computing MD5 digests. The final result is then converted to text form
 219 and returned.
 220
 221 Arguments:
 222   base      pointer to the md5 storage structure
 223   text      pointer to the final text vector
 224   length    length of the final text vector
 225   digest    points to 16 bytes in which to place the result
 226
 227 Returns:    nothing
 228 */
 229
 230 void
 231 md5_end(md5 *base, const uschar *text, int length, uschar *digest)
 232 {
 233 uschar work[64];
 234
 235 /* Process in chunks of 64 until we have less than 64 bytes left. */
 236
 237 while (length >= 64)
 238   {
 239   md5_mid(base, text);
 240   text += 64;
 241   length -= 64;
 242   }
 243
 244 /* If the remaining string contains more than 55 bytes, we must pad it
 245 out to 64, process it, and then set up the final chunk as 56 bytes of
 246 padding. If it has less than 56 bytes, we pad it out to 56 bytes as the
 247 final chunk. */
 248
 249 memcpy(work, text, length);
 250 work[length] = 0x80;
 251
 252 if (length > 55)
 253   {
 254   memset(work+length+1, 0, 63-length);
 255   md5_mid(base, work);
 256   base->length -= 64;
 257   memset(work, 0, 56);
 258   }
 259 else
 260   {
 261   memset(work+length+1, 0, 55-length);
 262   }
 263
 264 /* The final 8 bytes of the final chunk are a 64-bit representation of the
 265 length of the input string *bits*, before padding, low order word first, and
 266 low order bytes first in each word. This implementation is designed for short
 267 strings, and so operates with a single int counter only. */
 268
 269 length += base->length;   /* Total length in bytes */
 270 length <<= 3;             /* Total length in bits */
 271
 272 work[56] = length         & 0xff;
 273 work[57] = (length >>  8) & 0xff;
 274 work[58] = (length >> 16) & 0xff;
 275 work[59] = (length >> 24) & 0xff;
 276
 277 memset(work+60, 0, 4);
 278
 279 /* Process the final 64-byte chunk */
 280
 281 md5_mid(base, work);
 282
 283 /* Pass back the result, low-order byte first in each word. */
 284
 285 for (int i = 0; i < 4; i++)
 286   {
 287   register int x = base->abcd[i];
 288   *digest++ =  x        & 0xff;
 289   *digest++ = (x >>  8) & 0xff;
 290   *digest++ = (x >> 16) & 0xff;
 291   *digest++ = (x >> 24) & 0xff;
 292   }
 293 }
 294
 295
 296
 297 /*************************************************
 298 **************************************************
 299 *             Stand-alone test program           *
 300 **************************************************
 301 *************************************************/
 302
 303 #if defined STAND_ALONE & !defined CRAM_STAND_ALONE
 304
 305 /* Test values */
 306
 307 static uschar *tests[] = {
 308   "", "d41d8cd98f00b204e9800998ecf8427e",
 309
 310   "a", "0cc175b9c0f1b6a831c399e269772661",
 311
 312   "abc", "900150983cd24fb0d6963f7d28e17f72",
 313
 314   "message digest", "f96b697d7cb7938d525a2f31aaf161d0",
 315
 316   "abcdefghijklmnopqrstuvwxyz", "c3fcd3d76192e4007dfb496cca67e13b",
 317
 318   "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
 319      "d174ab98d277d9f5a5611c2c9f419d9f",
 320
 321   "1234567890123456789012345678901234567890123456789012345678901234567890"
 322   "1234567890",
 323     "57edf4a22be3c955ac49da2e2107b67a",
 324
 325   "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
 326   "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
 327   "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
 328     "a0842fcc02167127b0bb9a7c38e71ba8"
 329 };
 330
 331 int main(void)
 332 {
 333 md5 base;
 334 int i = 0x01020304;
 335 uschar *ctest = US (&i);
 336 uschar buffer[256];
 337 uschar digest[16];
 338 printf("Checking md5: %s-endian\n", (ctest[0] == 0x04)? "little" : "big");
 339
 340 for (i = 0; i < sizeof(tests)/sizeof(uschar *); i += 2)
 341   {
 342   uschar s[33];
 343   printf("%s\nShould be: %s\n", tests[i], tests[i+1]);
 344   md5_start(&base);
 345   md5_end(&base, tests[i], strlen(tests[i]), digest);
 346   for (int j = 0; j < 16; j++) sprintf(s+2*j, "%02x", digest[j]);
 347   printf("Computed:  %s\n", s);
 348   if (strcmp(s, tests[i+1]) != 0) printf("*** No match ***\n");
 349   printf("\n");
 350   }
 351 }
 352 #endif
 353
 354 /* End of md5.c */