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des.c

/*
 * FreeSec: libcrypt for NetBSD
 *
 * Copyright (c) 1994 David Burren
 * All rights reserved.
 *
 * Adapted for FreeBSD-2.0 by Geoffrey M. Rehmet
 *    this file should now *only* export crypt(), in order to make
 *    binaries of libcrypt exportable from the USA
 *
 * Adapted for FreeBSD-4.0 by Mark R V Murray
 *    this file should now *only* export crypt_des(), in order to make
 *    a module that can be optionally included in libcrypt.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the author nor the names of other contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This is an original implementation of the DES and the crypt(3) interfaces
 * by David Burren <davidb@werj.com.au>.
 *
 * An excellent reference on the underlying algorithm (and related
 * algorithms) is:
 *
 *    B. Schneier, Applied Cryptography: protocols, algorithms,
 *    and source code in C, John Wiley & Sons, 1994.
 *
 * Note that in that book's description of DES the lookups for the initial,
 * pbox, and final permutations are inverted (this has been brought to the
 * attention of the author).  A list of errata for this book has been
 * posted to the sci.crypt newsgroup by the author and is available for FTP.
 *
 * ARCHITECTURE ASSUMPTIONS:
 *    It is assumed that the 8-byte arrays passed by reference can be
 *    addressed as arrays of u_int32_t's (ie. the CPU is not picky about
 *    alignment).
 */

#define __FORCE_GLIBC
#include <sys/cdefs.h>
#include <sys/types.h>
#include <sys/param.h>
#include <netinet/in.h>
#include <pwd.h>
#include <string.h>
#include <crypt.h>

/* Re-entrantify me -- all this junk needs to be in 
 * struct crypt_data to make this really reentrant... */
static u_char     inv_key_perm[64];
static u_char     inv_comp_perm[56];
static u_char     u_sbox[8][64];
static u_char     un_pbox[32];
static u_int32_t en_keysl[16], en_keysr[16];
static u_int32_t de_keysl[16], de_keysr[16];
static u_int32_t ip_maskl[8][256], ip_maskr[8][256];
static u_int32_t fp_maskl[8][256], fp_maskr[8][256];
static u_int32_t key_perm_maskl[8][128], key_perm_maskr[8][128];
static u_int32_t comp_maskl[8][128], comp_maskr[8][128];
static u_int32_t saltbits;
static u_int32_t old_salt;
static u_int32_t old_rawkey0, old_rawkey1;


/* Static stuff that stays resident and doesn't change after 
 * being initialized, and therefore doesn't need to be made 
 * reentrant. */
static u_char     init_perm[64], final_perm[64];
static u_char     m_sbox[4][4096];
static u_int32_t psbox[4][256];




/* A pile of data */
static const u_char     ascii64[] = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

static const u_char     IP[64] = {
      58, 50, 42, 34, 26, 18, 10,  2, 60, 52, 44, 36, 28, 20, 12,  4,
      62, 54, 46, 38, 30, 22, 14,  6, 64, 56, 48, 40, 32, 24, 16,  8,
      57, 49, 41, 33, 25, 17,  9,  1, 59, 51, 43, 35, 27, 19, 11,  3,
      61, 53, 45, 37, 29, 21, 13,  5, 63, 55, 47, 39, 31, 23, 15,  7
};

static const u_char     key_perm[56] = {
      57, 49, 41, 33, 25, 17,  9,  1, 58, 50, 42, 34, 26, 18,
      10,  2, 59, 51, 43, 35, 27, 19, 11,  3, 60, 52, 44, 36,
      63, 55, 47, 39, 31, 23, 15,  7, 62, 54, 46, 38, 30, 22,
      14,  6, 61, 53, 45, 37, 29, 21, 13,  5, 28, 20, 12,  4
};

static const u_char     key_shifts[16] = {
      1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1
};

static const u_char     comp_perm[48] = {
      14, 17, 11, 24,  1,  5,  3, 28, 15,  6, 21, 10,
      23, 19, 12,  4, 26,  8, 16,  7, 27, 20, 13,  2,
      41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48,
      44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32
};

/*
 *    No E box is used, as it's replaced by some ANDs, shifts, and ORs.
 */

static const u_char     sbox[8][64] = {
      {
            14,  4, 13,  1,  2, 15, 11,  8,  3, 10,  6, 12,  5,  9,  0,  7,
             0, 15,  7,  4, 14,  2, 13,  1, 10,  6, 12, 11,  9,  5,  3,  8,
             4,  1, 14,  8, 13,  6,  2, 11, 15, 12,  9,  7,  3, 10,  5,  0,
            15, 12,  8,  2,  4,  9,  1,  7,  5, 11,  3, 14, 10,  0,  6, 13
      },
      {
            15,  1,  8, 14,  6, 11,  3,  4,  9,  7,  2, 13, 12,  0,  5, 10,
             3, 13,  4,  7, 15,  2,  8, 14, 12,  0,  1, 10,  6,  9, 11,  5,
             0, 14,  7, 11, 10,  4, 13,  1,  5,  8, 12,  6,  9,  3,  2, 15,
            13,  8, 10,  1,  3, 15,  4,  2, 11,  6,  7, 12,  0,  5, 14,  9
      },
      {
            10,  0,  9, 14,  6,  3, 15,  5,  1, 13, 12,  7, 11,  4,  2,  8,
            13,  7,  0,  9,  3,  4,  6, 10,  2,  8,  5, 14, 12, 11, 15,  1,
            13,  6,  4,  9,  8, 15,  3,  0, 11,  1,  2, 12,  5, 10, 14,  7,
             1, 10, 13,  0,  6,  9,  8,  7,  4, 15, 14,  3, 11,  5,  2, 12
      },
      {
             7, 13, 14,  3,  0,  6,  9, 10,  1,  2,  8,  5, 11, 12,  4, 15,
            13,  8, 11,  5,  6, 15,  0,  3,  4,  7,  2, 12,  1, 10, 14,  9,
            10,  6,  9,  0, 12, 11,  7, 13, 15,  1,  3, 14,  5,  2,  8,  4,
             3, 15,  0,  6, 10,  1, 13,  8,  9,  4,  5, 11, 12,  7,  2, 14
      },
      {
             2, 12,  4,  1,  7, 10, 11,  6,  8,  5,  3, 15, 13,  0, 14,  9,
            14, 11,  2, 12,  4,  7, 13,  1,  5,  0, 15, 10,  3,  9,  8,  6,
             4,  2,  1, 11, 10, 13,  7,  8, 15,  9, 12,  5,  6,  3,  0, 14,
            11,  8, 12,  7,  1, 14,  2, 13,  6, 15,  0,  9, 10,  4,  5,  3
      },
      {
            12,  1, 10, 15,  9,  2,  6,  8,  0, 13,  3,  4, 14,  7,  5, 11,
            10, 15,  4,  2,  7, 12,  9,  5,  6,  1, 13, 14,  0, 11,  3,  8,
             9, 14, 15,  5,  2,  8, 12,  3,  7,  0,  4, 10,  1, 13, 11,  6,
             4,  3,  2, 12,  9,  5, 15, 10, 11, 14,  1,  7,  6,  0,  8, 13
      },
      {
             4, 11,  2, 14, 15,  0,  8, 13,  3, 12,  9,  7,  5, 10,  6,  1,
            13,  0, 11,  7,  4,  9,  1, 10, 14,  3,  5, 12,  2, 15,  8,  6,
             1,  4, 11, 13, 12,  3,  7, 14, 10, 15,  6,  8,  0,  5,  9,  2,
             6, 11, 13,  8,  1,  4, 10,  7,  9,  5,  0, 15, 14,  2,  3, 12
      },
      {
            13,  2,  8,  4,  6, 15, 11,  1, 10,  9,  3, 14,  5,  0, 12,  7,
             1, 15, 13,  8, 10,  3,  7,  4, 12,  5,  6, 11,  0, 14,  9,  2,
             7, 11,  4,  1,  9, 12, 14,  2,  0,  6, 10, 13, 15,  3,  5,  8,
             2,  1, 14,  7,  4, 10,  8, 13, 15, 12,  9,  0,  3,  5,  6, 11
      }
};

static const u_char     pbox[32] = {
      16,  7, 20, 21, 29, 12, 28, 17,  1, 15, 23, 26,  5, 18, 31, 10,
       2,  8, 24, 14, 32, 27,  3,  9, 19, 13, 30,  6, 22, 11,  4, 25
};

static const u_int32_t bits32[32] =
{
      0x80000000, 0x40000000, 0x20000000, 0x10000000,
      0x08000000, 0x04000000, 0x02000000, 0x01000000,
      0x00800000, 0x00400000, 0x00200000, 0x00100000,
      0x00080000, 0x00040000, 0x00020000, 0x00010000,
      0x00008000, 0x00004000, 0x00002000, 0x00001000,
      0x00000800, 0x00000400, 0x00000200, 0x00000100,
      0x00000080, 0x00000040, 0x00000020, 0x00000010,
      0x00000008, 0x00000004, 0x00000002, 0x00000001
};

static const u_char     bits8[8] = { 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01 };
static const u_int32_t *bits28, *bits24;


static int 
ascii_to_bin(char ch)
{
      if (ch > 'z')
            return(0);
      if (ch >= 'a')
            return(ch - 'a' + 38);
      if (ch > 'Z')
            return(0);
      if (ch >= 'A')
            return(ch - 'A' + 12);
      if (ch > '9')
            return(0);
      if (ch >= '.')
            return(ch - '.');
      return(0);
}

static void
des_init(void)
{
      int   i, j, b, k, inbit, obit;
      u_int32_t   *p, *il, *ir, *fl, *fr;
      static int des_initialised = 0;

      if (des_initialised==1)
          return;

      old_rawkey0 = old_rawkey1 = 0L;
      saltbits = 0L;
      old_salt = 0L;
      bits24 = (bits28 = bits32 + 4) + 4;

      /*
       * Invert the S-boxes, reordering the input bits.
       */
      for (i = 0; i < 8; i++)
            for (j = 0; j < 64; j++) {
                  b = (j & 0x20) | ((j & 1) << 4) | ((j >> 1) & 0xf);
                  u_sbox[i][j] = sbox[i][b];
            }

      /*
       * Convert the inverted S-boxes into 4 arrays of 8 bits.
       * Each will handle 12 bits of the S-box input.
       */
      for (b = 0; b < 4; b++)
            for (i = 0; i < 64; i++)
                  for (j = 0; j < 64; j++)
                        m_sbox[b][(i << 6) | j] =
                              (u_char)((u_sbox[(b << 1)][i] << 4) |
                              u_sbox[(b << 1) + 1][j]);

      /*
       * Set up the initial & final permutations into a useful form, and
       * initialise the inverted key permutation.
       */
      for (i = 0; i < 64; i++) {
            init_perm[final_perm[i] = IP[i] - 1] = (u_char)i;
            inv_key_perm[i] = 255;
      }

      /*
       * Invert the key permutation and initialise the inverted key
       * compression permutation.
       */
      for (i = 0; i < 56; i++) {
            inv_key_perm[key_perm[i] - 1] = (u_char)i;
            inv_comp_perm[i] = 255;
      }

      /*
       * Invert the key compression permutation.
       */
      for (i = 0; i < 48; i++) {
            inv_comp_perm[comp_perm[i] - 1] = (u_char)i;
      }

      /*
       * Set up the OR-mask arrays for the initial and final permutations,
       * and for the key initial and compression permutations.
       */
      for (k = 0; k < 8; k++) {
            for (i = 0; i < 256; i++) {
                  *(il = &ip_maskl[k][i]) = 0L;
                  *(ir = &ip_maskr[k][i]) = 0L;
                  *(fl = &fp_maskl[k][i]) = 0L;
                  *(fr = &fp_maskr[k][i]) = 0L;
                  for (j = 0; j < 8; j++) {
                        inbit = 8 * k + j;
                        if (i & bits8[j]) {
                              if ((obit = init_perm[inbit]) < 32)
                                    *il |= bits32[obit];
                              else
                                    *ir |= bits32[obit-32];
                              if ((obit = final_perm[inbit]) < 32)
                                    *fl |= bits32[obit];
                              else
                                    *fr |= bits32[obit - 32];
                        }
                  }
            }
            for (i = 0; i < 128; i++) {
                  *(il = &key_perm_maskl[k][i]) = 0L;
                  *(ir = &key_perm_maskr[k][i]) = 0L;
                  for (j = 0; j < 7; j++) {
                        inbit = 8 * k + j;
                        if (i & bits8[j + 1]) {
                              if ((obit = inv_key_perm[inbit]) == 255)
                                    continue;
                              if (obit < 28)
                                    *il |= bits28[obit];
                              else
                                    *ir |= bits28[obit - 28];
                        }
                  }
                  *(il = &comp_maskl[k][i]) = 0L;
                  *(ir = &comp_maskr[k][i]) = 0L;
                  for (j = 0; j < 7; j++) {
                        inbit = 7 * k + j;
                        if (i & bits8[j + 1]) {
                              if ((obit=inv_comp_perm[inbit]) == 255)
                                    continue;
                              if (obit < 24)
                                    *il |= bits24[obit];
                              else
                                    *ir |= bits24[obit - 24];
                        }
                  }
            }
      }

      /*
       * Invert the P-box permutation, and convert into OR-masks for
       * handling the output of the S-box arrays setup above.
       */
      for (i = 0; i < 32; i++)
            un_pbox[pbox[i] - 1] = (u_char)i;

      for (b = 0; b < 4; b++)
            for (i = 0; i < 256; i++) {
                  *(p = &psbox[b][i]) = 0L;
                  for (j = 0; j < 8; j++) {
                        if (i & bits8[j])
                              *p |= bits32[un_pbox[8 * b + j]];
                  }
            }

      des_initialised = 1;
}


static void
setup_salt(long salt)
{
      u_int32_t   obit, saltbit;
      int   i;

      if (salt == old_salt)
            return;
      old_salt = salt;

      saltbits = 0L;
      saltbit = 1;
      obit = 0x800000;
      for (i = 0; i < 24; i++) {
            if (salt & saltbit)
                  saltbits |= obit;
            saltbit <<= 1;
            obit >>= 1;
      }
}


static int
des_setkey(const char *key)
{
      u_int32_t   k0, k1, rawkey0, rawkey1;
      int         shifts, round;

      des_init();

      rawkey0 = ntohl(*(const u_int32_t *) key);
      rawkey1 = ntohl(*(const u_int32_t *) (key + 4));

      if ((rawkey0 | rawkey1)
          && rawkey0 == old_rawkey0
          && rawkey1 == old_rawkey1) {
            /*
             * Already setup for this key.
             * This optimisation fails on a zero key (which is weak and
             * has bad parity anyway) in order to simplify the starting
             * conditions.
             */
            return(0);
      }
      old_rawkey0 = rawkey0;
      old_rawkey1 = rawkey1;

      /*
       *    Do key permutation and split into two 28-bit subkeys.
       */
      k0 = key_perm_maskl[0][rawkey0 >> 25]
         | key_perm_maskl[1][(rawkey0 >> 17) & 0x7f]
         | key_perm_maskl[2][(rawkey0 >> 9) & 0x7f]
         | key_perm_maskl[3][(rawkey0 >> 1) & 0x7f]
         | key_perm_maskl[4][rawkey1 >> 25]
         | key_perm_maskl[5][(rawkey1 >> 17) & 0x7f]
         | key_perm_maskl[6][(rawkey1 >> 9) & 0x7f]
         | key_perm_maskl[7][(rawkey1 >> 1) & 0x7f];
      k1 = key_perm_maskr[0][rawkey0 >> 25]
         | key_perm_maskr[1][(rawkey0 >> 17) & 0x7f]
         | key_perm_maskr[2][(rawkey0 >> 9) & 0x7f]
         | key_perm_maskr[3][(rawkey0 >> 1) & 0x7f]
         | key_perm_maskr[4][rawkey1 >> 25]
         | key_perm_maskr[5][(rawkey1 >> 17) & 0x7f]
         | key_perm_maskr[6][(rawkey1 >> 9) & 0x7f]
         | key_perm_maskr[7][(rawkey1 >> 1) & 0x7f];
      /*
       *    Rotate subkeys and do compression permutation.
       */
      shifts = 0;
      for (round = 0; round < 16; round++) {
            u_int32_t   t0, t1;

            shifts += key_shifts[round];

            t0 = (k0 << shifts) | (k0 >> (28 - shifts));
            t1 = (k1 << shifts) | (k1 >> (28 - shifts));

            de_keysl[15 - round] =
            en_keysl[round] = comp_maskl[0][(t0 >> 21) & 0x7f]
                        | comp_maskl[1][(t0 >> 14) & 0x7f]
                        | comp_maskl[2][(t0 >> 7) & 0x7f]
                        | comp_maskl[3][t0 & 0x7f]
                        | comp_maskl[4][(t1 >> 21) & 0x7f]
                        | comp_maskl[5][(t1 >> 14) & 0x7f]
                        | comp_maskl[6][(t1 >> 7) & 0x7f]
                        | comp_maskl[7][t1 & 0x7f];

            de_keysr[15 - round] =
            en_keysr[round] = comp_maskr[0][(t0 >> 21) & 0x7f]
                        | comp_maskr[1][(t0 >> 14) & 0x7f]
                        | comp_maskr[2][(t0 >> 7) & 0x7f]
                        | comp_maskr[3][t0 & 0x7f]
                        | comp_maskr[4][(t1 >> 21) & 0x7f]
                        | comp_maskr[5][(t1 >> 14) & 0x7f]
                        | comp_maskr[6][(t1 >> 7) & 0x7f]
                        | comp_maskr[7][t1 & 0x7f];
      }
      return(0);
}


static int
do_des(     u_int32_t l_in, u_int32_t r_in, u_int32_t *l_out, u_int32_t *r_out, int count)
{
      /*
       *    l_in, r_in, l_out, and r_out are in pseudo-"big-endian" format.
       */
      u_int32_t   l, r, *kl, *kr, *kl1, *kr1;
      u_int32_t   f, r48l, r48r;
      int         round;

      if (count == 0) {
            return(1);
      } else if (count > 0) {
            /*
             * Encrypting
             */
            kl1 = en_keysl;
            kr1 = en_keysr;
      } else {
            /*
             * Decrypting
             */
            count = -count;
            kl1 = de_keysl;
            kr1 = de_keysr;
      }

      /*
       *    Do initial permutation (IP).
       */
      l = ip_maskl[0][l_in >> 24]
        | ip_maskl[1][(l_in >> 16) & 0xff]
        | ip_maskl[2][(l_in >> 8) & 0xff]
        | ip_maskl[3][l_in & 0xff]
        | ip_maskl[4][r_in >> 24]
        | ip_maskl[5][(r_in >> 16) & 0xff]
        | ip_maskl[6][(r_in >> 8) & 0xff]
        | ip_maskl[7][r_in & 0xff];
      r = ip_maskr[0][l_in >> 24]
        | ip_maskr[1][(l_in >> 16) & 0xff]
        | ip_maskr[2][(l_in >> 8) & 0xff]
        | ip_maskr[3][l_in & 0xff]
        | ip_maskr[4][r_in >> 24]
        | ip_maskr[5][(r_in >> 16) & 0xff]
        | ip_maskr[6][(r_in >> 8) & 0xff]
        | ip_maskr[7][r_in & 0xff];

      while (count--) {
            /*
             * Do each round.
             */
            kl = kl1;
            kr = kr1;
            round = 16;
            while (round--) {
                  /*
                   * Expand R to 48 bits (simulate the E-box).
                   */
                  r48l  = ((r & 0x00000001) << 23)
                        | ((r & 0xf8000000) >> 9)
                        | ((r & 0x1f800000) >> 11)
                        | ((r & 0x01f80000) >> 13)
                        | ((r & 0x001f8000) >> 15);

                  r48r  = ((r & 0x0001f800) << 7)
                        | ((r & 0x00001f80) << 5)
                        | ((r & 0x000001f8) << 3)
                        | ((r & 0x0000001f) << 1)
                        | ((r & 0x80000000) >> 31);
                  /*
                   * Do salting for crypt() and friends, and
                   * XOR with the permuted key.
                   */
                  f = (r48l ^ r48r) & saltbits;
                  r48l ^= f ^ *kl++;
                  r48r ^= f ^ *kr++;
                  /*
                   * Do sbox lookups (which shrink it back to 32 bits)
                   * and do the pbox permutation at the same time.
                   */
                  f = psbox[0][m_sbox[0][r48l >> 12]]
                    | psbox[1][m_sbox[1][r48l & 0xfff]]
                    | psbox[2][m_sbox[2][r48r >> 12]]
                    | psbox[3][m_sbox[3][r48r & 0xfff]];
                  /*
                   * Now that we've permuted things, complete f().
                   */
                  f ^= l;
                  l = r;
                  r = f;
            }
            r = l;
            l = f;
      }
      /*
       * Do final permutation (inverse of IP).
       */
      *l_out      = fp_maskl[0][l >> 24]
            | fp_maskl[1][(l >> 16) & 0xff]
            | fp_maskl[2][(l >> 8) & 0xff]
            | fp_maskl[3][l & 0xff]
            | fp_maskl[4][r >> 24]
            | fp_maskl[5][(r >> 16) & 0xff]
            | fp_maskl[6][(r >> 8) & 0xff]
            | fp_maskl[7][r & 0xff];
      *r_out      = fp_maskr[0][l >> 24]
            | fp_maskr[1][(l >> 16) & 0xff]
            | fp_maskr[2][(l >> 8) & 0xff]
            | fp_maskr[3][l & 0xff]
            | fp_maskr[4][r >> 24]
            | fp_maskr[5][(r >> 16) & 0xff]
            | fp_maskr[6][(r >> 8) & 0xff]
            | fp_maskr[7][r & 0xff];
      return(0);
}


#if 0
static int
des_cipher(const char *in, char *out, u_int32_t salt, int count)
{
      u_int32_t   l_out, r_out, rawl, rawr;
      int         retval;
      union {
            u_int32_t   *ui32;
            const char  *c;
      } trans;

      des_init();

      setup_salt(salt);

      trans.c = in;
      rawl = ntohl(*trans.ui32++);
      rawr = ntohl(*trans.ui32);

      retval = do_des(rawl, rawr, &l_out, &r_out, count);

      trans.c = out;
      *trans.ui32++ = htonl(l_out);
      *trans.ui32 = htonl(r_out);
      return(retval);
}
#endif


void
setkey(const char *key)
{
      int   i, j;
      u_int32_t   packed_keys[2];
      u_char      *p;

      p = (u_char *) packed_keys;

      for (i = 0; i < 8; i++) {
            p[i] = 0;
            for (j = 0; j < 8; j++)
                  if (*key++ & 1)
                        p[i] |= bits8[j];
      }
      des_setkey(p);
}


void
encrypt(char *block, int flag)
{
      u_int32_t   io[2];
      u_char      *p;
      int   i, j;

      des_init();

      setup_salt(0L);
      p = block;
      for (i = 0; i < 2; i++) {
            io[i] = 0L;
            for (j = 0; j < 32; j++)
                  if (*p++ & 1)
                        io[i] |= bits32[j];
      }
      do_des(io[0], io[1], io, io + 1, flag ? -1 : 1);
      for (i = 0; i < 2; i++)
            for (j = 0; j < 32; j++)
                  block[(i << 5) | j] = (io[i] & bits32[j]) ? 1 : 0;
}

char *
__des_crypt(const char *key, const char *setting)
{
      u_int32_t   count, salt, l, r0, r1, keybuf[2];
      u_char            *p, *q;
      static char output[21];

      des_init();

      /*
       * Copy the key, shifting each character up by one bit
       * and padding with zeros.
       */
      q = (u_char *)keybuf;
      while (q - (u_char *)keybuf - 8) {
            *q++ = *key << 1;
            if (*(q - 1))
                  key++;
      }
      if (des_setkey((char *)keybuf))
            return(NULL);

#if 0
      if (*setting == _PASSWORD_EFMT1) {
            int         i;
            /*
             * "new"-style:
             *    setting - underscore, 4 bytes of count, 4 bytes of salt
             *    key - unlimited characters
             */
            for (i = 1, count = 0L; i < 5; i++)
                  count |= ascii_to_bin(setting[i]) << ((i - 1) * 6);

            for (i = 5, salt = 0L; i < 9; i++)
                  salt |= ascii_to_bin(setting[i]) << ((i - 5) * 6);

            while (*key) {
                  /*
                   * Encrypt the key with itself.
                   */
                  if (des_cipher((char *)keybuf, (char *)keybuf, 0L, 1))
                        return(NULL);
                  /*
                   * And XOR with the next 8 characters of the key.
                   */
                  q = (u_char *)keybuf;
                  while (q - (u_char *)keybuf - 8 && *key)
                        *q++ ^= *key++ << 1;

                  if (des_setkey((char *)keybuf))
                        return(NULL);
            }
            strncpy(output, setting, 9);

            /*
             * Double check that we weren't given a short setting.
             * If we were, the above code will probably have created
             * wierd values for count and salt, but we don't really care.
             * Just make sure the output string doesn't have an extra
             * NUL in it.
             */
            output[9] = '\0';
            p = (u_char *)output + strlen(output);
      } else 
#endif
      {
            /*
             * "old"-style:
             *    setting - 2 bytes of salt
             *    key - up to 8 characters
             */
            count = 25;

            salt = (ascii_to_bin(setting[1]) << 6)
                 |  ascii_to_bin(setting[0]);

            output[0] = setting[0];
            /*
             * If the encrypted password that the salt was extracted from
             * is only 1 character long, the salt will be corrupted.  We
             * need to ensure that the output string doesn't have an extra
             * NUL in it!
             */
            output[1] = setting[1] ? setting[1] : output[0];

            p = (u_char *)output + 2;
      }
      setup_salt(salt);
      /*
       * Do it.
       */
      if (do_des(0L, 0L, &r0, &r1, (int)count))
            return(NULL);
      /*
       * Now encode the result...
       */
      l = (r0 >> 8);
      *p++ = ascii64[(l >> 18) & 0x3f];
      *p++ = ascii64[(l >> 12) & 0x3f];
      *p++ = ascii64[(l >> 6) & 0x3f];
      *p++ = ascii64[l & 0x3f];

      l = (r0 << 16) | ((r1 >> 16) & 0xffff);
      *p++ = ascii64[(l >> 18) & 0x3f];
      *p++ = ascii64[(l >> 12) & 0x3f];
      *p++ = ascii64[(l >> 6) & 0x3f];
      *p++ = ascii64[l & 0x3f];

      l = r1 << 2;
      *p++ = ascii64[(l >> 12) & 0x3f];
      *p++ = ascii64[(l >> 6) & 0x3f];
      *p++ = ascii64[l & 0x3f];
      *p = 0;

      return(output);
}


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