src/md5.c

   1 /* md5.c - MD5 Message-Digest Algorithm
   2  *      Copyright (C) 1995, 1996, 1998, 1999 Free Software Foundation, Inc.
   3  *
   4  * according to the definition of MD5 in RFC 1321 from April 1992.
   5  * NOTE: This is *not* the same file as the one from glibc.
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the
   9  * Free Software Foundation; either version 2, or (at your option) any
  10  * later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software Foundation,
  19  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  20  */
  21 /* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.  */
  22 /* heavily modified for GnuPG by <werner.koch@guug.de> */
  23 /* modified again for Sylpheed by <wk@gnupg.org> 2001-02-11 */
  24
  25
  26 /* Test values:
  27  * ""                  D4 1D 8C D9 8F 00 B2 04  E9 80 09 98 EC F8 42 7E
  28  * "a"                 0C C1 75 B9 C0 F1 B6 A8  31 C3 99 E2 69 77 26 61
  29  * "abc                90 01 50 98 3C D2 4F B0  D6 96 3F 7D 28 E1 7F 72
  30  * "message digest"    F9 6B 69 7D 7C B7 93 8D  52 5A 2F 31 AA F1 61 D0
  31  */
  32
  33 #include <config.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <assert.h>
  38
  39 #include "utils.h"
  40 #include "md5.h"
  41
  42
  43 /****************
  44  * Rotate a 32 bit integer by n bytes
  45  */
  46 #if defined(__GNUC__) && defined(__i386__)
  47 static inline u32
  48 rol( u32 x, int n)
  49 {
  50         __asm__("roll %%cl,%0"
  51                 :"=r" (x)
  52                 :"0" (x),"c" (n));
  53         return x;
  54 }
  55 #else
  56 #define rol(x,n) ( ((x) << (n)) | ((x) >> (32-(n))) )
  57 #endif
  58
  59
  60 void
  61 md5_init(MD5_CONTEXT *ctx)
  62 {
  63         ctx->A = 0x67452301;
  64         ctx->B = 0xefcdab89;
  65         ctx->C = 0x98badcfe;
  66         ctx->D = 0x10325476;
  67
  68         ctx->nblocks = 0;
  69         ctx->count = 0;
  70         ctx->finalized = 0;
  71 }
  72
  73 /* These are the four functions used in the four steps of the MD5 algorithm
  74    and defined in the RFC 1321.  The first function is a little bit optimized
  75    (as found in Colin Plumbs public domain implementation).  */
  76 /* #define FF(b, c, d) ((b & c) | (~b & d)) */
  77 #define FF(b, c, d) (d ^ (b & (c ^ d)))
  78 #define FG(b, c, d) FF (d, b, c)
  79 #define FH(b, c, d) (b ^ c ^ d)
  80 #define FI(b, c, d) (c ^ (b | ~d))
  81
  82
  83 /****************
  84  * transform n*64 bytes
  85  */
  86 static void
  87 transform(MD5_CONTEXT *ctx, const unsigned char *data)
  88 {
  89         u32 correct_words[16];
  90         u32 A = ctx->A;
  91         u32 B = ctx->B;
  92         u32 C = ctx->C;
  93         u32 D = ctx->D;
  94         u32 *cwp = correct_words;
  95
  96 #ifdef BIG_ENDIAN_HOST
  97         {
  98                 int i;
  99                 const unsigned char *p2, *p1;
 100
 101                 for (i = 0, p1 = data, p2 = (unsigned char*)correct_words;
 102                      i < 16; i++, p2 += 4) {
 103                         p2[3] = *p1++;
 104                         p2[2] = *p1++;
 105                         p2[1] = *p1++;
 106                         p2[0] = *p1++;
 107                 }
 108         }
 109 #else
 110         memcpy(correct_words, data, 64);
 111 #endif
 112
 113
 114 #define OP(a, b, c, d, s, T)                            \
 115         do {                                            \
 116                 a += FF (b, c, d) + (*cwp++) + T;       \
 117                 a = rol(a, s);                          \
 118                 a += b;                                 \
 119         } while (0)
 120
 121         /* Before we start, one word about the strange constants.
 122            They are defined in RFC 1321 as
 123
 124            T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
 125          */
 126
 127         /* Round 1.  */
 128         OP (A, B, C, D,  7, 0xd76aa478);
 129         OP (D, A, B, C, 12, 0xe8c7b756);
 130         OP (C, D, A, B, 17, 0x242070db);
 131         OP (B, C, D, A, 22, 0xc1bdceee);
 132         OP (A, B, C, D,  7, 0xf57c0faf);
 133         OP (D, A, B, C, 12, 0x4787c62a);
 134         OP (C, D, A, B, 17, 0xa8304613);
 135         OP (B, C, D, A, 22, 0xfd469501);
 136         OP (A, B, C, D,  7, 0x698098d8);
 137         OP (D, A, B, C, 12, 0x8b44f7af);
 138         OP (C, D, A, B, 17, 0xffff5bb1);
 139         OP (B, C, D, A, 22, 0x895cd7be);
 140         OP (A, B, C, D,  7, 0x6b901122);
 141         OP (D, A, B, C, 12, 0xfd987193);
 142         OP (C, D, A, B, 17, 0xa679438e);
 143         OP (B, C, D, A, 22, 0x49b40821);
 144
 145 #undef OP
 146 #define OP(f, a, b, c, d, k, s, T)  \
 147         do {                                                    \
 148                 a += f (b, c, d) + correct_words[k] + T;        \
 149                 a = rol(a, s);                                  \
 150                 a += b;                                         \
 151         } while (0)
 152
 153         /* Round 2.  */
 154         OP (FG, A, B, C, D,  1,  5, 0xf61e2562);
 155         OP (FG, D, A, B, C,  6,  9, 0xc040b340);
 156         OP (FG, C, D, A, B, 11, 14, 0x265e5a51);
 157         OP (FG, B, C, D, A,  0, 20, 0xe9b6c7aa);
 158         OP (FG, A, B, C, D,  5,  5, 0xd62f105d);
 159         OP (FG, D, A, B, C, 10,  9, 0x02441453);
 160         OP (FG, C, D, A, B, 15, 14, 0xd8a1e681);
 161         OP (FG, B, C, D, A,  4, 20, 0xe7d3fbc8);
 162         OP (FG, A, B, C, D,  9,  5, 0x21e1cde6);
 163         OP (FG, D, A, B, C, 14,  9, 0xc33707d6);
 164         OP (FG, C, D, A, B,  3, 14, 0xf4d50d87);
 165         OP (FG, B, C, D, A,  8, 20, 0x455a14ed);
 166         OP (FG, A, B, C, D, 13,  5, 0xa9e3e905);
 167         OP (FG, D, A, B, C,  2,  9, 0xfcefa3f8);
 168         OP (FG, C, D, A, B,  7, 14, 0x676f02d9);
 169         OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a);
 170
 171         /* Round 3.  */
 172         OP (FH, A, B, C, D,  5,  4, 0xfffa3942);
 173         OP (FH, D, A, B, C,  8, 11, 0x8771f681);
 174         OP (FH, C, D, A, B, 11, 16, 0x6d9d6122);
 175         OP (FH, B, C, D, A, 14, 23, 0xfde5380c);
 176         OP (FH, A, B, C, D,  1,  4, 0xa4beea44);
 177         OP (FH, D, A, B, C,  4, 11, 0x4bdecfa9);
 178         OP (FH, C, D, A, B,  7, 16, 0xf6bb4b60);
 179         OP (FH, B, C, D, A, 10, 23, 0xbebfbc70);
 180         OP (FH, A, B, C, D, 13,  4, 0x289b7ec6);
 181         OP (FH, D, A, B, C,  0, 11, 0xeaa127fa);
 182         OP (FH, C, D, A, B,  3, 16, 0xd4ef3085);
 183         OP (FH, B, C, D, A,  6, 23, 0x04881d05);
 184         OP (FH, A, B, C, D,  9,  4, 0xd9d4d039);
 185         OP (FH, D, A, B, C, 12, 11, 0xe6db99e5);
 186         OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8);
 187         OP (FH, B, C, D, A,  2, 23, 0xc4ac5665);
 188
 189         /* Round 4.  */
 190         OP (FI, A, B, C, D,  0,  6, 0xf4292244);
 191         OP (FI, D, A, B, C,  7, 10, 0x432aff97);
 192         OP (FI, C, D, A, B, 14, 15, 0xab9423a7);
 193         OP (FI, B, C, D, A,  5, 21, 0xfc93a039);
 194         OP (FI, A, B, C, D, 12,  6, 0x655b59c3);
 195         OP (FI, D, A, B, C,  3, 10, 0x8f0ccc92);
 196         OP (FI, C, D, A, B, 10, 15, 0xffeff47d);
 197         OP (FI, B, C, D, A,  1, 21, 0x85845dd1);
 198         OP (FI, A, B, C, D,  8,  6, 0x6fa87e4f);
 199         OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
 200         OP (FI, C, D, A, B,  6, 15, 0xa3014314);
 201         OP (FI, B, C, D, A, 13, 21, 0x4e0811a1);
 202         OP (FI, A, B, C, D,  4,  6, 0xf7537e82);
 203         OP (FI, D, A, B, C, 11, 10, 0xbd3af235);
 204         OP (FI, C, D, A, B,  2, 15, 0x2ad7d2bb);
 205         OP (FI, B, C, D, A,  9, 21, 0xeb86d391);
 206
 207         /* Put checksum in context given as argument.  */
 208         ctx->A += A;
 209         ctx->B += B;
 210         ctx->C += C;
 211         ctx->D += D;
 212 }
 213
 214
 215
 216 /* The routine updates the message-digest context to
 217  * account for the presence of each of the characters inBuf[0..inLen-1]
 218  * in the message whose digest is being computed.
 219  */
 220 void
 221 md5_update(MD5_CONTEXT *hd, const unsigned char *inbuf, size_t inlen)
 222 {
 223         if (hd->count == 64) { /* flush the buffer */
 224                 transform( hd, hd->buf );
 225                 hd->count = 0;
 226                 hd->nblocks++;
 227         }
 228         if (!inbuf)
 229                 return;
 230         if (hd->count) {
 231                 for (; inlen && hd->count < 64; inlen--)
 232                         hd->buf[hd->count++] = *inbuf++;
 233                 md5_update(hd, NULL, 0);
 234                 if (!inlen)
 235                         return;
 236         }
 237
 238         while (inlen >= 64) {
 239                 transform(hd, inbuf);
 240                 hd->count = 0;
 241                 hd->nblocks++;
 242                 inlen -= 64;
 243                 inbuf += 64;
 244         }
 245
 246         for (; inlen && hd->count < 64; inlen--)
 247                 hd->buf[hd->count++] = *inbuf++;
 248 }
 249
 250
 251
 252 /* The routine final terminates the message-digest computation and
 253  * ends with the desired message digest in mdContext->digest[0...15].
 254  * The handle is prepared for a new MD5 cycle.
 255  * Returns 16 bytes representing the digest.
 256  */
 257
 258 static void
 259 do_final(MD5_CONTEXT *hd)
 260 {
 261         u32 t, msb, lsb;
 262         unsigned char *p;
 263
 264         md5_update(hd, NULL, 0); /* flush */
 265
 266         msb = 0;
 267         t = hd->nblocks;
 268         if ((lsb = t << 6) < t) /* multiply by 64 to make a byte count */
 269                 msb++;
 270         msb += t >> 26;
 271         t = lsb;
 272         if ((lsb = t + hd->count) < t) /* add the count */
 273                 msb++;
 274         t = lsb;
 275         if ((lsb = t << 3) < t) /* multiply by 8 to make a bit count */
 276                 msb++;
 277         msb += t >> 29;
 278
 279         if (hd->count < 56) { /* enough room */
 280                 hd->buf[hd->count++] = 0x80; /* pad */
 281                 while(hd->count < 56)
 282                         hd->buf[hd->count++] = 0;  /* pad */
 283         } else { /* need one extra block */
 284                 hd->buf[hd->count++] = 0x80; /* pad character */
 285                 while (hd->count < 64)
 286                         hd->buf[hd->count++] = 0;
 287                 md5_update(hd, NULL, 0);  /* flush */
 288                 memset(hd->buf, 0, 56); /* fill next block with zeroes */
 289         }
 290
 291         /* append the 64 bit count */
 292         hd->buf[56] = lsb      ;
 293         hd->buf[57] = lsb >>  8;
 294         hd->buf[58] = lsb >> 16;
 295         hd->buf[59] = lsb >> 24;
 296         hd->buf[60] = msb      ;
 297         hd->buf[61] = msb >>  8;
 298         hd->buf[62] = msb >> 16;
 299         hd->buf[63] = msb >> 24;
 300         transform(hd, hd->buf);
 301
 302         p = hd->buf;
 303 #ifdef BIG_ENDIAN_HOST
 304 #define X(a) do { *p++ = hd->##a      ; *p++ = hd->##a >> 8;      \
 305                   *p++ = hd->##a >> 16; *p++ = hd->##a >> 24; } while(0)
 306 #else /* little endian */
 307         /*#define X(a) do { *(u32*)p = hd->##a ; p += 4; } while(0)*/
 308         /* Unixware's cpp doesn't like the above construct so we do it his way:
 309          * (reported by Allan Clark) */
 310 #define X(a) do { *(u32*)p = (*hd).a ; p += 4; } while(0)
 311 #endif
 312         X(A);
 313         X(B);
 314         X(C);
 315         X(D);
 316 #undef X
 317         hd->finalized = 1;
 318 }
 319
 320 void
 321 md5_final(unsigned char *digest, MD5_CONTEXT *ctx)
 322 {
 323         if (!ctx->finalized)
 324                 do_final(ctx);
 325         memcpy(digest, ctx->buf, 16);
 326 }
 327
 328 /*
 329  * Creates a MD5 digest in hex fomrat (lowercase letters) from the
 330  * string S.  hextdigest but be buffer of at lease 33 bytes!
 331  */
 332 void
 333 md5_hex_digest(char *hexdigest, const unsigned char *s)
 334 {
 335         int i;
 336         MD5_CTX_syl context;
 337         unsigned char digest[16];
 338
 339         md5_init(&context);
 340         md5_update(&context, s, strlen(s));
 341         md5_final(digest, &context);
 342
 343         for (i = 0; i < 16; i++)
 344                 sprintf(hexdigest + 2 * i, "%02x", digest[i]);
 345 }
 346
 347
 348 /*
 349 ** Function: md5_hmac
 350 ** taken from the file rfc2104.txt
 351 ** written by Martin Schaaf <mascha@ma-scha.de>
 352 */
 353 void
 354 md5_hmac(unsigned char *digest,
 355          const unsigned char* text, int text_len,
 356          const unsigned char* key, int key_len)
 357 {
 358         MD5_CTX_syl context;
 359         unsigned char k_ipad[64];    /* inner padding -
 360                                       * key XORd with ipad
 361                                       */
 362         unsigned char k_opad[64];    /* outer padding -
 363                                       * key XORd with opad
 364                                       */
 365         /* unsigned char tk[16]; */
 366         int i;
 367
 368         /* start out by storing key in pads */
 369         memset(k_ipad, 0, sizeof k_ipad);
 370         memset(k_opad, 0, sizeof k_opad);
 371         if (key_len > 64) {
 372                 /* if key is longer than 64 bytes reset it to key=MD5(key) */
 373                 MD5_CTX_syl tctx;
 374
 375                 md5_init(&tctx);
 376                 md5_update(&tctx, key, key_len);
 377                 md5_final(k_ipad, &tctx);
 378                 md5_final(k_opad, &tctx);
 379         } else {
 380                 memcpy(k_ipad, key, key_len);
 381                 memcpy(k_opad, key, key_len);
 382         }
 383
 384         /*
 385          * the HMAC_MD5 transform looks like:
 386          *
 387          * MD5(K XOR opad, MD5(K XOR ipad, text))
 388          *
 389          * where K is an n byte key
 390          * ipad is the byte 0x36 repeated 64 times
 391          * opad is the byte 0x5c repeated 64 times
 392          * and text is the data being protected
 393          */
 394
 395
 396         /* XOR key with ipad and opad values */
 397         for (i = 0; i < 64; i++) {
 398                 k_ipad[i] ^= 0x36;
 399                 k_opad[i] ^= 0x5c;
 400         }
 401
 402         /*
 403          * perform inner MD5
 404          */
 405         md5_init(&context);                   /* init context for 1st
 406                                                * pass */
 407         md5_update(&context, k_ipad, 64);     /* start with inner pad */
 408         md5_update(&context, text, text_len); /* then text of datagram */
 409         md5_final(digest, &context);          /* finish up 1st pass */
 410         /*
 411          * perform outer MD5
 412          */
 413         md5_init(&context);                   /* init context for 2nd
 414                                                * pass */
 415         md5_update(&context, k_opad, 64);     /* start with outer pad */
 416         md5_update(&context, digest, 16);     /* then results of 1st
 417                                                * hash */
 418         md5_final(digest, &context);          /* finish up 2nd pass */
 419 }
 420
 421
 422 void
 423 md5_hex_hmac(char *hexdigest,
 424              const unsigned char* text, int text_len,
 425              const unsigned char* key, int key_len)
 426 {
 427         unsigned char digest[16];
 428         int i;
 429
 430         md5_hmac(digest, text, text_len, key, key_len);
 431         for (i = 0; i < 16; i++)
 432                 sprintf(hexdigest + 2 * i, "%02x", digest[i]);
 433 }