libcrypt/md5.c

   1 /*
   2  * MD5C.C - RSA Data Security, Inc., MD5 message-digest algorithm
   3  *
   4  * Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
   5  * rights reserved.
   6  *
   7  * License to copy and use this software is granted provided that it
   8  * is identified as the "RSA Data Security, Inc. MD5 Message-Digest
   9  * Algorithm" in all material mentioning or referencing this software
  10  * or this function.
  11  *
  12  * License is also granted to make and use derivative works provided
  13  * that such works are identified as "derived from the RSA Data
  14  * Security, Inc. MD5 Message-Digest Algorithm" in all material
  15  * mentioning or referencing the derived work.
  16  *
  17  * RSA Data Security, Inc. makes no representations concerning either
  18  * the merchantability of this software or the suitability of this
  19  * software for any particular purpose. It is provided "as is"
  20  * without express or implied warranty of any kind.
  21  *
  22  * These notices must be retained in any copies of any part of this
  23  * documentation and/or software.
  24  *
  25  * $FreeBSD: src/lib/libmd/md5c.c,v 1.9.2.1 1999/08/29 14:57:12 peter Exp $
  26  *
  27  * This code is the same as the code published by RSA Inc.  It has been
  28  * edited for clarity and style only.
  29  *
  30  * ----------------------------------------------------------------------------
  31  * The md5_crypt() function was taken from freeBSD's libcrypt and contains
  32  * this license:
  33  *    "THE BEER-WARE LICENSE" (Revision 42):
  34  *     <phk@login.dknet.dk> wrote this file.  As long as you retain this notice you
  35  *     can do whatever you want with this stuff. If we meet some day, and you think
  36  *     this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
  37  *
  38  * $FreeBSD: src/lib/libcrypt/crypt.c,v 1.7.2.1 1999/08/29 14:56:33 peter Exp $
  39  *
  40  * ----------------------------------------------------------------------------
  41  * On April 19th, 2001 md5_crypt() was modified to make it reentrant
  42  * by Erik Andersen <andersen@uclibc.org>
  43  *
  44  *
  45  * June 28, 2001             Manuel Novoa III
  46  *
  47  * "Un-inlined" code using loops and static const tables in order to
  48  * reduce generated code size (on i386 from approx 4k to approx 2.5k).
  49  *
  50  * June 29, 2001             Manuel Novoa III
  51  *
  52  * Completely removed static PADDING array.
  53  *
  54  * Reintroduced the loop unrolling in MD5_Transform and added the
  55  * MD5_SIZE_OVER_SPEED option for configurability.  Define below as:
  56  *       0    fully unrolled loops
  57  *       1    partially unrolled (4 ops per loop)
  58  *       2    no unrolling -- introduces the need to swap 4 variables (slow)
  59  *       3    no unrolling and all 4 loops merged into one with switch
  60  *               in each loop (glacial)
  61  * On i386, sizes are roughly (-Os -fno-builtin):
  62  *     0: 3k     1: 2.5k     2: 2.2k     3: 2k
  63  *
  64  *
  65  * Since SuSv3 does not require crypt_r, modified again August 7, 2002
  66  * by Erik Andersen to remove reentrance stuff...
  67  */
  68
  69 /*
  70  * Valid values are  1 (fastest/largest) to 3 (smallest/slowest).
  71  */
  72 #define MD5_SIZE_OVER_SPEED 3
  73
  74 /**********************************************************************/
  75
  76 #include <sys/types.h>
  77 #include <string.h>
  78 #include <unistd.h>
  79 #include <stdio.h>
  80 #include <crypt.h>
  81 #include <sys/cdefs.h>
  82 #include "libcrypt.h"
  83
  84 /* MD5 context. */
  85 struct MD5Context {
  86   u_int32_t state[4];   /* state (ABCD) */
  87   u_int32_t count[2];   /* number of bits, modulo 2^64 (lsb first) */
  88   unsigned char buffer[64];     /* input buffer */
  89 };
  90
  91 static void   __md5_Init (struct MD5Context *);
  92 static void   __md5_Update (struct MD5Context *, const unsigned char *, unsigned int);
  93 static void   __md5_Pad (struct MD5Context *);
  94 static void   __md5_Final (unsigned char [16], struct MD5Context *);
  95 static void __md5_Transform __P((u_int32_t [4], const unsigned char [64]));
  96
  97
  98 #define MD5_MAGIC_STR "$1$"
  99 #define MD5_MAGIC_LEN (sizeof(MD5_MAGIC_STR) - 1)
 100 static const unsigned char __md5__magic[] = MD5_MAGIC_STR;
 101 static const unsigned char __md5_itoa64[] =             /* 0 ... 63 => ascii - 64 */
 102         "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 103
 104
 105 #ifdef i386
 106 #define __md5_Encode memcpy
 107 #define __md5_Decode memcpy
 108 #else /* i386 */
 109
 110 /*
 111  * __md5_Encodes input (u_int32_t) into output (unsigned char). Assumes len is
 112  * a multiple of 4.
 113  */
 114
 115 static void
 116 __md5_Encode (unsigned char *output, u_int32_t *input, unsigned int len)
 117 {
 118         unsigned int i, j;
 119
 120         for (i = 0, j = 0; j < len; i++, j += 4) {
 121                 output[j] = (unsigned char)(input[i] & 0xff);
 122                 output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);
 123                 output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
 124                 output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
 125         }
 126 }
 127
 128 /*
 129  * __md5_Decodes input (unsigned char) into output (u_int32_t). Assumes len is
 130  * a multiple of 4.
 131  */
 132
 133 static void
 134 __md5_Decode (u_int32_t *output, const unsigned char *input, unsigned int len)
 135 {
 136         unsigned int i, j;
 137
 138         for (i = 0, j = 0; j < len; i++, j += 4)
 139                 output[i] = ((u_int32_t)input[j]) | (((u_int32_t)input[j+1]) << 8) |
 140                     (((u_int32_t)input[j+2]) << 16) | (((u_int32_t)input[j+3]) << 24);
 141 }
 142 #endif /* i386 */
 143
 144 /* F, G, H and I are basic MD5 functions. */
 145 #define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
 146 #define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
 147 #define H(x, y, z) ((x) ^ (y) ^ (z))
 148 #define I(x, y, z) ((y) ^ ((x) | (~z)))
 149
 150 /* ROTATE_LEFT rotates x left n bits. */
 151 #define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
 152
 153 /*
 154  * FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
 155  * Rotation is separate from addition to prevent recomputation.
 156  */
 157 #define FF(a, b, c, d, x, s, ac) { \
 158         (a) += F ((b), (c), (d)) + (x) + (u_int32_t)(ac); \
 159         (a) = ROTATE_LEFT ((a), (s)); \
 160         (a) += (b); \
 161         }
 162 #define GG(a, b, c, d, x, s, ac) { \
 163         (a) += G ((b), (c), (d)) + (x) + (u_int32_t)(ac); \
 164         (a) = ROTATE_LEFT ((a), (s)); \
 165         (a) += (b); \
 166         }
 167 #define HH(a, b, c, d, x, s, ac) { \
 168         (a) += H ((b), (c), (d)) + (x) + (u_int32_t)(ac); \
 169         (a) = ROTATE_LEFT ((a), (s)); \
 170         (a) += (b); \
 171         }
 172 #define II(a, b, c, d, x, s, ac) { \
 173         (a) += I ((b), (c), (d)) + (x) + (u_int32_t)(ac); \
 174         (a) = ROTATE_LEFT ((a), (s)); \
 175         (a) += (b); \
 176         }
 177
 178 /* MD5 initialization. Begins an MD5 operation, writing a new context. */
 179
 180 static void __md5_Init (struct MD5Context *context)
 181 {
 182         context->count[0] = context->count[1] = 0;
 183
 184         /* Load magic initialization constants.  */
 185         context->state[0] = 0x67452301;
 186         context->state[1] = 0xefcdab89;
 187         context->state[2] = 0x98badcfe;
 188         context->state[3] = 0x10325476;
 189 }
 190
 191 /*
 192  * MD5 block update operation. Continues an MD5 message-digest
 193  * operation, processing another message block, and updating the
 194  * context.
 195  */
 196
 197 static void __md5_Update ( struct MD5Context *context, const unsigned char *input, unsigned int inputLen)
 198 {
 199         unsigned int i, idx, partLen;
 200
 201         /* Compute number of bytes mod 64 */
 202         idx = (unsigned int)((context->count[0] >> 3) & 0x3F);
 203
 204         /* Update number of bits */
 205         if ((context->count[0] += ((u_int32_t)inputLen << 3))
 206             < ((u_int32_t)inputLen << 3))
 207                 context->count[1]++;
 208         context->count[1] += ((u_int32_t)inputLen >> 29);
 209
 210         partLen = 64 - idx;
 211
 212         /* Transform as many times as possible. */
 213         if (inputLen >= partLen) {
 214                 memcpy((void *)&context->buffer[idx], (const void *)input,
 215                     partLen);
 216                 __md5_Transform (context->state, context->buffer);
 217
 218                 for (i = partLen; i + 63 < inputLen; i += 64)
 219                         __md5_Transform (context->state, &input[i]);
 220
 221                 idx = 0;
 222         }
 223         else
 224                 i = 0;
 225
 226         /* Buffer remaining input */
 227         memcpy ((void *)&context->buffer[idx], (const void *)&input[i],
 228             inputLen-i);
 229 }
 230
 231 /*
 232  * MD5 padding. Adds padding followed by original length.
 233  */
 234
 235 static void __md5_Pad ( struct MD5Context *context)
 236 {
 237         unsigned char bits[8];
 238         unsigned int idx, padLen;
 239         unsigned char PADDING[64];
 240
 241         memset(PADDING, 0, sizeof(PADDING));
 242         PADDING[0] = 0x80;
 243
 244         /* Save number of bits */
 245         __md5_Encode (bits, context->count, 8);
 246
 247         /* Pad out to 56 mod 64. */
 248         idx = (unsigned int)((context->count[0] >> 3) & 0x3f);
 249         padLen = (idx < 56) ? (56 - idx) : (120 - idx);
 250         __md5_Update (context, PADDING, padLen);
 251
 252         /* Append length (before padding) */
 253         __md5_Update (context, bits, 8);
 254 }
 255
 256 /*
 257  * MD5 finalization. Ends an MD5 message-digest operation, writing the
 258  * the message digest and zeroizing the context.
 259  */
 260
 261 static void __md5_Final ( unsigned char digest[16], struct MD5Context *context)
 262 {
 263         /* Do padding. */
 264         __md5_Pad (context);
 265
 266         /* Store state in digest */
 267         __md5_Encode (digest, context->state, 16);
 268
 269         /* Zeroize sensitive information. */
 270         memset ((void *)context, 0, sizeof (*context));
 271 }
 272
 273 /* MD5 basic transformation. Transforms state based on block. */
 274
 275 static void __md5_Transform (u_int32_t state[4], const unsigned char block[64])
 276 {
 277         u_int32_t a, b, c, d, x[16];
 278 #if MD5_SIZE_OVER_SPEED > 1
 279         u_int32_t temp;
 280         const char *ps;
 281
 282         static const char S[] = {
 283                 7, 12, 17, 22,
 284                 5, 9, 14, 20,
 285                 4, 11, 16, 23,
 286                 6, 10, 15, 21
 287         };
 288 #endif /* MD5_SIZE_OVER_SPEED > 1 */
 289
 290 #if MD5_SIZE_OVER_SPEED > 0
 291         const u_int32_t *pc;
 292         const char *pp;
 293         int i;
 294
 295         static const u_int32_t C[] = {
 296                                                                 /* round 1 */
 297                 0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee,
 298                 0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
 299                 0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
 300                 0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
 301                                                                 /* round 2 */
 302                 0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa,
 303                 0xd62f105d, 0x2441453,  0xd8a1e681, 0xe7d3fbc8,
 304                 0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,
 305                 0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
 306                                                                 /* round 3 */
 307                 0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c,
 308                 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
 309                 0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x4881d05,
 310                 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
 311                                                                 /* round 4 */
 312                 0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039,
 313                 0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
 314                 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
 315                 0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391
 316         };
 317
 318         static const char P[] = {
 319                 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, /* 1 */
 320                 1, 6, 11, 0, 5, 10, 15, 4, 9, 14, 3, 8, 13, 2, 7, 12, /* 2 */
 321                 5, 8, 11, 14, 1, 4, 7, 10, 13, 0, 3, 6, 9, 12, 15, 2, /* 3 */
 322                 0, 7, 14, 5, 12, 3, 10, 1, 8, 15, 6, 13, 4, 11, 2, 9  /* 4 */
 323         };
 324
 325 #endif /* MD5_SIZE_OVER_SPEED > 0 */
 326
 327         __md5_Decode (x, block, 64);
 328
 329         a = state[0]; b = state[1]; c = state[2]; d = state[3];
 330
 331 #if MD5_SIZE_OVER_SPEED > 2
 332         pc = C; pp = P; ps = S - 4;
 333
 334         for ( i = 0 ; i < 64 ; i++ ) {
 335                 if ((i&0x0f) == 0) ps += 4;
 336                 temp = a;
 337                 switch (i>>4) {
 338                         case 0:
 339                                 temp += F(b,c,d);
 340                                 break;
 341                         case 1:
 342                                 temp += G(b,c,d);
 343                                 break;
 344                         case 2:
 345                                 temp += H(b,c,d);
 346                                 break;
 347                         case 3:
 348                                 temp += I(b,c,d);
 349                                 break;
 350                 }
 351                 temp += x[(int)(*pp++)] + *pc++;
 352                 temp = ROTATE_LEFT(temp, ps[i&3]);
 353                 temp += b;
 354                 a = d; d = c; c = b; b = temp;
 355         }
 356 #elif MD5_SIZE_OVER_SPEED > 1
 357         pc = C; pp = P; ps = S;
 358
 359         /* Round 1 */
 360         for ( i = 0 ; i < 16 ; i++ ) {
 361                 FF (a, b, c, d, x[(int)(*pp++)], ps[i&0x3], *pc++);
 362                 temp = d; d = c; c = b; b = a; a = temp;
 363         }
 364
 365         /* Round 2 */
 366         ps += 4;
 367         for ( ; i < 32 ; i++ ) {
 368                 GG (a, b, c, d, x[(int)(*pp++)], ps[i&0x3], *pc++);
 369                 temp = d; d = c; c = b; b = a; a = temp;
 370         }
 371         /* Round 3 */
 372         ps += 4;
 373         for ( ; i < 48 ; i++ ) {
 374                 HH (a, b, c, d, x[(int)(*pp++)], ps[i&0x3], *pc++);
 375                 temp = d; d = c; c = b; b = a; a = temp;
 376         }
 377
 378         /* Round 4 */
 379         ps += 4;
 380         for ( ; i < 64 ; i++ ) {
 381                 II (a, b, c, d, x[(int)(*pp++)], ps[i&0x3], *pc++);
 382                 temp = d; d = c; c = b; b = a; a = temp;
 383         }
 384 #elif MD5_SIZE_OVER_SPEED > 0
 385         pc = C; pp = P;
 386
 387         /* Round 1 */
 388         for ( i = 0 ; i < 4 ; i++ ) {
 389                 FF (a, b, c, d, x[(int)(*pp++)],  7, *pc++);
 390                 FF (d, a, b, c, x[(int)(*pp++)], 12, *pc++);
 391                 FF (c, d, a, b, x[(int)(*pp++)], 17, *pc++);
 392                 FF (b, c, d, a, x[(int)(*pp++)], 22, *pc++);
 393         }
 394
 395         /* Round 2 */
 396         for ( i = 0 ; i < 4 ; i++ ) {
 397                 GG (a, b, c, d, x[(int)(*pp++)],  5, *pc++);
 398                 GG (d, a, b, c, x[(int)(*pp++)],  9, *pc++);
 399                 GG (c, d, a, b, x[(int)(*pp++)], 14, *pc++);
 400                 GG (b, c, d, a, x[(int)(*pp++)], 20, *pc++);
 401         }
 402         /* Round 3 */
 403         for ( i = 0 ; i < 4 ; i++ ) {
 404                 HH (a, b, c, d, x[(int)(*pp++)],  4, *pc++);
 405                 HH (d, a, b, c, x[(int)(*pp++)], 11, *pc++);
 406                 HH (c, d, a, b, x[(int)(*pp++)], 16, *pc++);
 407                 HH (b, c, d, a, x[(int)(*pp++)], 23, *pc++);
 408         }
 409
 410         /* Round 4 */
 411         for ( i = 0 ; i < 4 ; i++ ) {
 412                 II (a, b, c, d, x[(int)(*pp++)],  6, *pc++);
 413                 II (d, a, b, c, x[(int)(*pp++)], 10, *pc++);
 414                 II (c, d, a, b, x[(int)(*pp++)], 15, *pc++);
 415                 II (b, c, d, a, x[(int)(*pp++)], 21, *pc++);
 416         }
 417 #else
 418         /* Round 1 */
 419 #define S11 7
 420 #define S12 12
 421 #define S13 17
 422 #define S14 22
 423         FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
 424         FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
 425         FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
 426         FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
 427         FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
 428         FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
 429         FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
 430         FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
 431         FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
 432         FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
 433         FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
 434         FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
 435         FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
 436         FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
 437         FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
 438         FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */
 439
 440         /* Round 2 */
 441 #define S21 5
 442 #define S22 9
 443 #define S23 14
 444 #define S24 20
 445         GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
 446         GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
 447         GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
 448         GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
 449         GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
 450         GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
 451         GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
 452         GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
 453         GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
 454         GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
 455         GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
 456         GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
 457         GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
 458         GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
 459         GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
 460         GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */
 461
 462         /* Round 3 */
 463 #define S31 4
 464 #define S32 11
 465 #define S33 16
 466 #define S34 23
 467         HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
 468         HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
 469         HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
 470         HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
 471         HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
 472         HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
 473         HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
 474         HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
 475         HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
 476         HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
 477         HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
 478         HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
 479         HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
 480         HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
 481         HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
 482         HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */
 483
 484         /* Round 4 */
 485 #define S41 6
 486 #define S42 10
 487 #define S43 15
 488 #define S44 21
 489         II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
 490         II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
 491         II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
 492         II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
 493         II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
 494         II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
 495         II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
 496         II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
 497         II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
 498         II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
 499         II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
 500         II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
 501         II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
 502         II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
 503         II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
 504         II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */
 505 #endif
 506
 507         state[0] += a;
 508         state[1] += b;
 509         state[2] += c;
 510         state[3] += d;
 511
 512         /* Zeroize sensitive information. */
 513         memset ((void *)x, 0, sizeof (x));
 514 }
 515
 516
 517 static void __md5_to64( char *s, unsigned long v, int n)
 518 {
 519         while (--n >= 0) {
 520                 *s++ = __md5_itoa64[v&0x3f];
 521                 v >>= 6;
 522         }
 523 }
 524
 525 /*
 526  * UNIX password
 527  *
 528  * Use MD5 for what it is best at...
 529  */
 530
 531 char *__md5_crypt(const unsigned char *pw, const unsigned char *salt)
 532 {
 533         /* Static stuff */
 534         /* "$1$" + salt_up_to_8_chars + "$" + 22_bytes_of_hash + NUL */
 535         static char passwd[3 + 8 + 1 + 22 + 1];
 536
 537         const unsigned char *sp, *ep;
 538         char *p;
 539         unsigned char   final[17];      /* final[16] exists only to aid in looping */
 540         int sl,pl,i,pw_len;
 541         struct MD5Context ctx,ctx1;
 542         unsigned long l;
 543
 544         /* Refine the Salt first */
 545         sp = salt;
 546
 547         /* If it starts with the magic string, then skip that */
 548         if(!strncmp(sp,__md5__magic,MD5_MAGIC_LEN))
 549                 sp += MD5_MAGIC_LEN;
 550
 551         /* It stops at the first '$', max 8 chars */
 552         for(ep=sp;*ep && *ep != '$' && ep < (sp+8);ep++)
 553                 continue;
 554
 555         /* get the length of the true salt */
 556         sl = ep - sp;
 557
 558         __md5_Init(&ctx);
 559
 560         /* The password first, since that is what is most unknown */
 561         pw_len = strlen(pw);
 562         __md5_Update(&ctx,pw,pw_len);
 563
 564         /* Then our magic string */
 565         __md5_Update(&ctx,__md5__magic,MD5_MAGIC_LEN);
 566
 567         /* Then the raw salt */
 568         __md5_Update(&ctx,sp,sl);
 569
 570         /* Then just as many characters of the MD5(pw,salt,pw) */
 571         __md5_Init(&ctx1);
 572         __md5_Update(&ctx1,pw,pw_len);
 573         __md5_Update(&ctx1,sp,sl);
 574         __md5_Update(&ctx1,pw,pw_len);
 575         __md5_Final(final,&ctx1);
 576         for(pl = pw_len; pl > 0; pl -= 16)
 577                 __md5_Update(&ctx,final,pl>16 ? 16 : pl);
 578
 579         /* Don't leave anything around in vm they could use. */
 580         memset(final,0,sizeof final);
 581
 582         /* Then something really weird... */
 583         for (i = pw_len; i ; i >>= 1) {
 584                 __md5_Update(&ctx, ((i&1) ? final : (const unsigned char *) pw), 1);
 585         }
 586
 587         /* Now make the output string */
 588         strcpy(passwd,__md5__magic); /* 3 bytes */
 589         strncpy(passwd+MD5_MAGIC_LEN,(char*)sp,sl); /* 8 or less */
 590         passwd[MD5_MAGIC_LEN+sl] = '$';
 591
 592         __md5_Final(final,&ctx);
 593
 594         /*
 595          * and now, just to make sure things don't run too fast
 596          * On a 60 Mhz Pentium this takes 34 msec, so you would
 597          * need 30 seconds to build a 1000 entry dictionary...
 598          */
 599         for(i=0;i<1000;i++) {
 600                 __md5_Init(&ctx1);
 601                 if(i & 1)
 602                         __md5_Update(&ctx1,pw,pw_len);
 603                 else
 604                         __md5_Update(&ctx1,final,16);
 605
 606                 if(i % 3)
 607                         __md5_Update(&ctx1,sp,sl);
 608
 609                 if(i % 7)
 610                         __md5_Update(&ctx1,pw,pw_len);
 611
 612                 if(i & 1)
 613                         __md5_Update(&ctx1,final,16);
 614                 else
 615                         __md5_Update(&ctx1,pw,pw_len);
 616                 __md5_Final(final,&ctx1);
 617         }
 618
 619         /* Add 5*4+2 = 22 bytes of hash, + NUL byte. */
 620         p = passwd + MD5_MAGIC_LEN + sl + 1;
 621         final[16] = final[5];
 622         for ( i=0 ; i < 5 ; i++ ) {
 623                 l = (final[i]<<16) | (final[i+6]<<8) | final[i+12];
 624                 __md5_to64(p,l,4);
 625                 p += 4;
 626         }
 627         l = final[11];
 628         __md5_to64(p,l,2);
 629         p += 2;
 630         *p = '\0';
 631
 632         /* Don't leave anything around in vm they could use. */
 633         memset(final,0,sizeof final);
 634
 635         return passwd;
 636 }
 637