Fix redefinition of _GNU_SOURCE.

[uclibc-ng.git] / libcrypt / 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).
 */

#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>
#include "libcrypt.h"
#include "des_tables.c"

/* Re-entrantify me -- all this junk needs to be in
 * struct crypt_data to make this really reentrant... */
static u_int32_t en_keysl[16], en_keysr[16];
static u_int32_t de_keysl[16], de_keysr[16];
static u_int32_t saltbits;
static u_int32_t old_salt;
static u_int32_t old_rawkey0, old_rawkey1;

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

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_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 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)
{
        static int des_initialised = 0;

        if (des_initialised==1)
                return;

        old_rawkey0 = old_rawkey1 = 0L;
        saltbits = 0L;
        old_salt = 0L;

        des_initialised = 1;
}

static void
setup_salt(u_int32_t 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 void
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;
        }
        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];
        }
}


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;
        }
        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;
                do {
                        /* 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;
                } while (--round);
                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((char *)p);
}


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

        des_init();

        setup_salt(0L);
        p = (u_char*)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 unsigned char *key, const unsigned 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++;
        }
        des_setkey((char *)keybuf);

#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;

                        des_setkey((char *)keybuf);
                }
                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);
}