des.c

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/*
 * Copyright (C) 1998,1999,2000,2001 Nikos Mavroyanopoulos
 * 
 * This library is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU Library General Public License as published 
 * by the Free Software Foundation; either version 2 of the License, or 
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
 
/* Sofware DES functions
 * written 12 Dec 1986 by Phil Karn, KA9Q; large sections adapted from
 * the 1977 public-domain program by Jim Gillogly
 * Modified for additional speed - 6 December 1988 Phil Karn
 * Modified for parameterized key schedules - Jan 1991 Phil Karn
 * Callers now allocate a key schedule as follows:
 *  kn = (char (*)[8])malloc(sizeof(char) * 8 * 16);
 *  or
 *  char kn[16][8];
 */
 
/* modified in order to use the libmcrypt API by Nikos Mavroyanopoulos 
 * All modifications are placed under the license of libmcrypt.
 */
 
#include <config.h>
 
#if HAVE_STRING_H
#include <string.h>
#endif /* HAVE_STRING_H */
 
#include <freetds/tds.h>
#include <freetds/bytes.h>
#include "des.h"
 
void
tds_des_set_odd_parity(des_cblock key)
{
 
    int i;
    unsigned char parity;
 
    for (i = 0; i < 8; i++) {
        parity = key[i];
 
        parity ^= parity >> 4;
        parity ^= parity >> 2;
        parity ^= parity >> 1;
 
        key[i] = (key[i] & 0xfe) | (parity & 1);
    }
}
 
#ifndef HAVE_NETTLE
 
static void permute_ip(des_cblock inblock, DES_KEY * key, des_cblock outblock);
static void permute_fp(des_cblock inblock, DES_KEY * key, des_cblock outblock);
static void perminit_ip(DES_KEY * key);
static void spinit(DES_KEY * key);
static void perminit_fp(DES_KEY * key);
static TDS_UINT f(DES_KEY * key, register TDS_UINT r, register unsigned char *subkey);
 
/* Tables defined in the Data Encryption Standard documents */
 
/* initial permutation IP */
static const char ip[] = {
    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
};
 
/* final permutation IP^-1 */
static const char fp[] = {
    40, 8, 48, 16, 56, 24, 64, 32,
    39, 7, 47, 15, 55, 23, 63, 31,
    38, 6, 46, 14, 54, 22, 62, 30,
    37, 5, 45, 13, 53, 21, 61, 29,
    36, 4, 44, 12, 52, 20, 60, 28,
    35, 3, 43, 11, 51, 19, 59, 27,
    34, 2, 42, 10, 50, 18, 58, 26,
    33, 1, 41, 9, 49, 17, 57, 25
};
 
/* expansion operation matrix
 * This is for reference only; it is unused in the code
 * as the f() function performs it implicitly for speed
 */
#ifdef notdef
static char ei[] = {
    32, 1, 2, 3, 4, 5,
    4, 5, 6, 7, 8, 9,
    8, 9, 10, 11, 12, 13,
    12, 13, 14, 15, 16, 17,
    16, 17, 18, 19, 20, 21,
    20, 21, 22, 23, 24, 25,
    24, 25, 26, 27, 28, 29,
    28, 29, 30, 31, 32, 1
};
#endif
 
/* permuted choice table (key) */
static const char pc1[] = {
    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
};
 
/* number left rotations of pc1 */
static const char totrot[] = {
    1, 2, 4, 6, 8, 10, 12, 14, 15, 17, 19, 21, 23, 25, 27, 28
};
 
/* permuted choice key (table) */
static const char pc2[] = {
    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
};
 
/* The (in)famous S-boxes */
static const char si[8][64] = {
    /* S1 */
    {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},
 
    /* S2 */
    {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},
 
    /* S3 */
    {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},
 
    /* S4 */
    {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},
 
    /* S5 */
    {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},
 
    /* S6 */
    {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},
 
    /* S7 */
    {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},
 
    /* S8 */
    {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},
 
};
 
#ifdef notdef
/* 32-bit permutation function P used on the output of the S-boxes */
static const char p32i[] = {
    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
};
#endif
 
#define P32I_INDEX_ROW(n,i,a,b,c,d) \
    n==a ? 0+i : n==b ? 1+i : n==c ? 2+i : n==d ? 3+i
#define P32I_INDEX(n) \
    (P32I_INDEX_ROW(n, 0, 16, 7, 20, 21) :\
     P32I_INDEX_ROW(n, 4, 29, 12, 28, 17) :\
     P32I_INDEX_ROW(n, 8, 1, 15, 23, 26) :\
     P32I_INDEX_ROW(n,12, 5, 18, 31, 10) :\
     P32I_INDEX_ROW(n,16, 2, 8, 24, 14) :\
     P32I_INDEX_ROW(n,20, 32, 27, 3, 9) :\
     P32I_INDEX_ROW(n,24, 19, 13, 30, 6) :\
     P32I_INDEX_ROW(n,28, 22, 11, 4, 25) : 0x7f)
 
static const char pbox[32] = {
    P32I_INDEX( 1),
    P32I_INDEX( 2),
    P32I_INDEX( 3),
    P32I_INDEX( 4),
    P32I_INDEX( 5),
    P32I_INDEX( 6),
    P32I_INDEX( 7),
    P32I_INDEX( 8),
    P32I_INDEX( 9),
    P32I_INDEX(10),
    P32I_INDEX(11),
    P32I_INDEX(12),
    P32I_INDEX(13),
    P32I_INDEX(14),
    P32I_INDEX(15),
    P32I_INDEX(16),
    P32I_INDEX(17),
    P32I_INDEX(18),
    P32I_INDEX(19),
    P32I_INDEX(20),
    P32I_INDEX(21),
    P32I_INDEX(22),
    P32I_INDEX(23),
    P32I_INDEX(24),
    P32I_INDEX(25),
    P32I_INDEX(26),
    P32I_INDEX(27),
    P32I_INDEX(28),
    P32I_INDEX(29),
    P32I_INDEX(30),
    P32I_INDEX(31),
    P32I_INDEX(32),
};
 
/* End of DES-defined tables */
 
/* Lookup tables initialized once only at startup by des_init() */
 
/* bit 0 is left-most in byte */
static const int bytebit[] = {
    0200, 0100, 040, 020, 010, 04, 02, 01
};
 
static const int nibblebit[] = {
    010, 04, 02, 01
};
 
/* Allocate space and initialize DES lookup arrays
 * mode == 0: standard Data Encryption Algorithm
 */
static int
des_init(DES_KEY * key)
{
 
    spinit(key);
    perminit_ip(key);
    perminit_fp(key);
 
    return 0;
}
 
 
/* Set key (initialize key schedule array) */
int
tds_des_set_key(DES_KEY * dkey, const des_cblock user_key, size_t len)
{
    char pc1m[56];      /* place to modify pc1 into */
    char pcr[56];       /* place to rotate pc1 into */
    register int i, j, l;
    int m;
 
    memset(dkey, '\0', sizeof(DES_KEY));
    des_init(dkey);
 
    /* Clear key schedule */
 
 
    for (j = 0; j < 56; j++) {  /* convert pc1 to bits of key */
        l = pc1[j] - 1; /* integer bit location  */
        m = l & 07; /* find bit              */
        pc1m[j] = (user_key[l >> 3] &   /* find which key byte l is in */
               bytebit[m])  /* and which bit of that byte */
            ? 1 : 0;    /* and store 1-bit result */
 
    }
    for (i = 0; i < 16; i++) {  /* key chunk for each iteration */
        for (j = 0; j < 56; j++)    /* rotate pc1 the right amount */
            pcr[j] = pc1m[(l = j + totrot[i]) < (j < 28 ? 28 : 56) ? l : l - 28];
        /* rotate left and right halves independently */
        for (j = 0; j < 48; j++) {  /* select bits individually */
            /* check bit that goes to kn[j] */
            if (pcr[pc2[j] - 1]) {
                /* mask it in if it's there */
                l = j % 6;
                dkey->kn[i][j / 6] |= bytebit[l] >> 2;
            }
        }
    }
    return 0;
}
 
/* In-place encryption of 64-bit block */
void
tds_des_encrypt(DES_KEY * key, des_cblock block)
{
    register TDS_UINT left, right;
    register unsigned char *knp;
    TDS_UINT work[2];   /* Working data storage */
 
    permute_ip(block, key, (unsigned char *) work); /* Initial Permutation */
    left = TDS_GET_A4BE(&work[0]);
    right = TDS_GET_A4BE(&work[1]);
 
    /* Do the 16 rounds.
     * The rounds are numbered from 0 to 15. On even rounds
     * the right half is fed to f() and the result exclusive-ORs
     * the left half; on odd rounds the reverse is done.
     */
    knp = &key->kn[0][0];
    left ^= f(key, right, knp);
    knp += 8;
    right ^= f(key, left, knp);
    knp += 8;
    left ^= f(key, right, knp);
    knp += 8;
    right ^= f(key, left, knp);
    knp += 8;
    left ^= f(key, right, knp);
    knp += 8;
    right ^= f(key, left, knp);
    knp += 8;
    left ^= f(key, right, knp);
    knp += 8;
    right ^= f(key, left, knp);
    knp += 8;
    left ^= f(key, right, knp);
    knp += 8;
    right ^= f(key, left, knp);
    knp += 8;
    left ^= f(key, right, knp);
    knp += 8;
    right ^= f(key, left, knp);
    knp += 8;
    left ^= f(key, right, knp);
    knp += 8;
    right ^= f(key, left, knp);
    knp += 8;
    left ^= f(key, right, knp);
    knp += 8;
    right ^= f(key, left, knp);
 
    /* Left/right half swap, plus byte swap if little-endian */
    TDS_PUT_A4BE(&work[0], right);
    TDS_PUT_A4BE(&work[1], left);
    permute_fp((unsigned char *) work, key, block); /* Inverse initial permutation */
}
 
/* In-place decryption of 64-bit block. This function is the mirror
 * image of encryption; exactly the same steps are taken, but in
 * reverse order
 */
#if 0
void
_mcrypt_decrypt(DES_KEY * key, unsigned char *block)
{
    register TDS_UINT left, right;
    register unsigned char *knp;
    TDS_UINT work[2];   /* Working data storage */
 
    permute_ip(block, key, (unsigned char *) work); /* Initial permutation */
 
    /* Left/right half swap, plus byte swap if little-endian */
    right = TDS_GET_A4BE(&work[0]);
    left  = TDS_GET_A4BE(&work[1]);
    /* Do the 16 rounds in reverse order.
     * The rounds are numbered from 15 to 0. On even rounds
     * the right half is fed to f() and the result exclusive-ORs
     * the left half; on odd rounds the reverse is done.
     */
    knp = &key->kn[15][0];
    right ^= f(key, left, knp);
    knp -= 8;
    left ^= f(key, right, knp);
    knp -= 8;
    right ^= f(key, left, knp);
    knp -= 8;
    left ^= f(key, right, knp);
    knp -= 8;
    right ^= f(key, left, knp);
    knp -= 8;
    left ^= f(key, right, knp);
    knp -= 8;
    right ^= f(key, left, knp);
    knp -= 8;
    left ^= f(key, right, knp);
    knp -= 8;
    right ^= f(key, left, knp);
    knp -= 8;
    left ^= f(key, right, knp);
    knp -= 8;
    right ^= f(key, left, knp);
    knp -= 8;
    left ^= f(key, right, knp);
    knp -= 8;
    right ^= f(key, left, knp);
    knp -= 8;
    left ^= f(key, right, knp);
    knp -= 8;
    right ^= f(key, left, knp);
    knp -= 8;
    left ^= f(key, right, knp);
 
    TDS_PUT_A4BE(&work[0], left);
    TDS_PUT_A4BE(&work[1], right);
    permute_fp((unsigned char *) work, key, block); /* Inverse initial permutation */
}
#endif
 
/* Permute inblock with perm */
static void
permute_ip(des_cblock inblock, DES_KEY * key, des_cblock outblock)
{
    register unsigned char *ib, *ob;    /* ptr to input or output block */
    register unsigned char *p, *q;
    register int j;
 
    /* Clear output block */
    memset(outblock, '\0', 8);
 
    ib = inblock;
    for (j = 0; j < 16; j += 2, ib++) { /* for each input nibble */
        ob = outblock;
        p = key->iperm[j][(*ib >> 4) & 0xf];
        q = key->iperm[j + 1][*ib & 0xf];
        /* and each output byte, OR the masks together */
        *ob++ |= *p++ | *q++;
        *ob++ |= *p++ | *q++;
        *ob++ |= *p++ | *q++;
        *ob++ |= *p++ | *q++;
        *ob++ |= *p++ | *q++;
        *ob++ |= *p++ | *q++;
        *ob++ |= *p++ | *q++;
        *ob++ |= *p++ | *q++;
    }
}
 
/* Permute inblock with perm */
static void
permute_fp(des_cblock inblock, DES_KEY * key, des_cblock outblock)
{
    register unsigned char *ib, *ob;    /* ptr to input or output block */
    register unsigned char *p, *q;
    register int j;
 
    /* Clear output block */
    memset(outblock, '\0', 8);
 
    ib = inblock;
    for (j = 0; j < 16; j += 2, ib++) { /* for each input nibble */
        ob = outblock;
        p = key->fperm[j][(*ib >> 4) & 0xf];
        q = key->fperm[j + 1][*ib & 0xf];
        /* and each output byte, OR the masks together */
        *ob++ |= *p++ | *q++;
        *ob++ |= *p++ | *q++;
        *ob++ |= *p++ | *q++;
        *ob++ |= *p++ | *q++;
        *ob++ |= *p++ | *q++;
        *ob++ |= *p++ | *q++;
        *ob++ |= *p++ | *q++;
        *ob++ |= *p++ | *q++;
    }
}
 
/* The nonlinear function f(r,k), the heart of DES */
static TDS_UINT
f(DES_KEY * key, register TDS_UINT r, register unsigned char *subkey)
{
    register const TDS_UINT *spp;
    register TDS_UINT rval, rt;
    register int er;
 
#ifdef  TRACE
        tdsdump_log(TDS_DBG_FUNC,
                    "f(%08lx, %02x %02x %02x %02x %02x %02x %02x %02x) = ",
                    r, subkey[0], subkey[1], subkey[2], subkey[3], subkey[4],
                    subkey[5], subkey[6], subkey[7]);
#endif
    /* Run E(R) ^ K through the combined S & P boxes.
     * This code takes advantage of a convenient regularity in
     * E, namely that each group of 6 bits in E(R) feeding
     * a single S-box is a contiguous segment of R.
     */
    subkey += 7;
 
    /* Compute E(R) for each block of 6 bits, and run thru boxes */
    er = ((int) r << 1) | ((r & 0x80000000) ? 1 : 0);
    spp = &key->sp[7][0];
    rval = spp[(er ^ *subkey--) & 0x3f];
    spp -= 64;
    rt = (TDS_UINT) r >> 3;
    rval |= spp[((int) rt ^ *subkey--) & 0x3f];
    spp -= 64;
    rt >>= 4;
    rval |= spp[((int) rt ^ *subkey--) & 0x3f];
    spp -= 64;
    rt >>= 4;
    rval |= spp[((int) rt ^ *subkey--) & 0x3f];
    spp -= 64;
    rt >>= 4;
    rval |= spp[((int) rt ^ *subkey--) & 0x3f];
    spp -= 64;
    rt >>= 4;
    rval |= spp[((int) rt ^ *subkey--) & 0x3f];
    spp -= 64;
    rt >>= 4;
    rval |= spp[((int) rt ^ *subkey--) & 0x3f];
    spp -= 64;
    rt >>= 4;
    rt |= (r & 1) << 5;
    rval |= spp[((int) rt ^ *subkey) & 0x3f];
#ifdef  TRACE
        tdsdump_log(TDS_DBG_FUNC, " %08lx\n", rval);
#endif
    return rval;
}
 
/* initialize a perm array */
static void
perminit_ip(DES_KEY * key)
{
    register int l, j, k;
    int i, m;
 
    /* Clear the permutation array */
    memset(key->iperm, '\0', 16 * 16 * 8);
 
    for (i = 0; i < 16; i++)    /* each input nibble position */
        for (j = 0; j < 16; j++)    /* each possible input nibble */
            for (k = 0; k < 64; k++) {  /* each output bit position */
                l = ip[k] - 1;  /* where does this bit come from */
                if ((l >> 2) != i)  /* does it come from input posn? */
                    continue;   /* if not, bit k is 0    */
                if (!(j & nibblebit[l & 3]))
                    continue;   /* any such bit in input? */
                m = k & 07; /* which bit is this in the byte */
                key->iperm[i][j][k >> 3] |= bytebit[m];
            }
}
 
static void
perminit_fp(DES_KEY * key)
{
    register int l, j, k;
    int i, m;
 
    /* Clear the permutation array */
    memset(key->fperm, '\0', 16 * 16 * 8);
 
    for (i = 0; i < 16; i++)    /* each input nibble position */
        for (j = 0; j < 16; j++)    /* each possible input nibble */
            for (k = 0; k < 64; k++) {  /* each output bit position */
                l = fp[k] - 1;  /* where does this bit come from */
                if ((l >> 2) != i)  /* does it come from input posn? */
                    continue;   /* if not, bit k is 0    */
                if (!(j & nibblebit[l & 3]))
                    continue;   /* any such bit in input? */
                m = k & 07; /* which bit is this in the byte */
                key->fperm[i][j][k >> 3] |= bytebit[m];
            }
}
 
/* Initialize the lookup table for the combined S and P boxes */
static void
spinit(DES_KEY * key)
{
    int i, s, j, rowcol;
    TDS_UINT val;
 
    for (s = 0; s < 8; s++) {   /* For each S-box */
        for (i = 0; i < 64; i++) {  /* For each possible input */
            val = 0;
            /* The row number is formed from the first and last
             * bits; the column number is from the middle 4
             */
            rowcol = (i & 32) | ((i & 1) ? 16 : 0) | ((i >> 1) & 0xf);
            for (j = 0; j < 4; j++) {   /* For each output bit */
                if (si[s][rowcol] & (8 >> j)) {
                    val |= 1L << (31 - pbox[4 * s + j]);
                }
            }
            key->sp[s][i] = val;
        }
    }
}
 
#endif
 
/* ECB MODE */
 
int
tds_des_ecb_encrypt(const void *plaintext, size_t len, DES_KEY * akey,
                    unsigned char *output)
{
        size_t j;
    const unsigned char *plain = (const unsigned char *) plaintext;
 
    for (j = 0; j < len / 8; j++) {
        memcpy(&output[j * 8], &plain[j * 8], 8);
        tds_des_encrypt(akey, &output[j * 8]);
    }
    if (j == 0 && len != 0)
        return -1;  /* no blocks were encrypted */
    return 0;
}