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[netbsd-mini2440.git] / bin / ed / cbc.c

/*      $NetBSD: cbc.c,v 1.20 2009/07/26 02:06:37 dholland Exp $        */

/* cbc.c: This file contains the encryption routines for the ed line editor */
/*-
 * Copyright (c) 1993 The Regents of the University of California.
 * All rights reserved.
 *
 * 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 University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *      from: @(#)bdes.c        5.5 (Berkeley) 6/27/91
 */

/*-
 * Copyright (c) 1993 Andrew Moore, Talke Studio.
 * All rights reserved.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *      from: @(#)bdes.c        5.5 (Berkeley) 6/27/91
 */

#include <sys/cdefs.h>
#ifndef lint
#if 0
static char *rcsid = "@(#)cbc.c,v 1.2 1994/02/01 00:34:36 alm Exp";
#else
__RCSID("$NetBSD: cbc.c,v 1.20 2009/07/26 02:06:37 dholland Exp $");
#endif
#endif /* not lint */

#include <sys/types.h>
#include <ctype.h>
#include <errno.h>
#include <pwd.h>
#ifdef DES
#include <time.h>
#endif

#include "ed.h"


/*
 * Define a divisor for rand() that yields a uniform distribution in the
 * range 0-255.
 */
#define RAND_DIV (((unsigned) RAND_MAX + 1) >> 8)

/*
 * BSD and System V systems offer special library calls that do
 * block move_liness and fills, so if possible we take advantage of them
 */
#define MEMCPY(dest,src,len)    memcpy((dest),(src),(len))
#define MEMZERO(dest,len)       memset((dest), 0, (len))

/* Hide the calls to the primitive encryption routines. */
#define DES_KEY(buf) \
        if (des_setkey(buf)) \
                des_error("des_setkey");
#define DES_XFORM(buf) \
        if (des_cipher(buf, buf, 0L, (inverse ? -1 : 1))) \
                des_error("des_cipher");

/*
 * read/write - no error checking
 */
#define READ(buf, n, fp)        fread(buf, sizeof(char), n, fp)
#define WRITE(buf, n, fp)       fwrite(buf, sizeof(char), n, fp)

/*
 * some things to make references easier
 */
typedef char Desbuf[8];
#define CHAR(x,i)       (x[i])
#define UCHAR(x,i)      (x[i])
#define BUFFER(x)       (x)
#define UBUFFER(x)      (x)

#ifdef DES
/*
 * global variables and related macros
 */

static Desbuf ivec;                     /* initialization vector */
static Desbuf pvec;                     /* padding vector */
static char bits[] = {                  /* used to extract bits from a char */
        '\200', '\100', '\040', '\020', '\010', '\004', '\002', '\001'
};
static int pflag;                       /* 1 to preserve parity bits */

static char des_buf[8]; /* shared buffer for get_des_char/put_des_char */
static int des_ct = 0;          /* count for get_des_char/put_des_char */
static int des_n = 0;           /* index for put_des_char/get_des_char */
#endif


static void des_error(const char *);
static int hex_to_binary(int, int);
static void expand_des_key(char *, char *);
static void set_des_key(char *);
static int cbc_decode(char *, FILE *);
static int cbc_encode(char *, int, FILE *);


/* init_des_cipher: initialize DES */
void
init_des_cipher(void)
{
#ifdef DES
        int i;

        des_ct = des_n = 0;

        /* initialize the initialization vector */
        MEMZERO(ivec, 8);

        /* intialize the padding vector */
        srand((unsigned) time((time_t *) 0));
        for (i = 0; i < 8; i++)
                CHAR(pvec, i) = (char) (rand()/RAND_DIV);
#endif
}


/* get_des_char: return next char in an encrypted file */
int
get_des_char(FILE *fp)
{
#ifdef DES
        if (des_n >= des_ct) {
                des_n = 0;
                des_ct = cbc_decode(des_buf, fp);
        }
        return (des_ct > 0) ? (unsigned char) des_buf[des_n++] : EOF;
#else
        return EOF;
#endif
}


/* put_des_char: write a char to an encrypted file; return char written */
int
put_des_char(int c, FILE *fp)
{
#ifdef DES
        if (des_n == sizeof des_buf) {
                des_ct = cbc_encode(des_buf, des_n, fp);
                des_n = 0;
        }
        return (des_ct >= 0) ? (unsigned char) (des_buf[des_n++] = c) : EOF;
#else
        return EOF;
#endif
}


/* flush_des_file: flush an encrypted file's output; return status */
int
flush_des_file(FILE *fp)
{
#ifdef DES
        if (des_n == sizeof des_buf) {
                des_ct = cbc_encode(des_buf, des_n, fp);
                des_n = 0;
        }
        return (des_ct >= 0 && cbc_encode(des_buf, des_n, fp) >= 0) ? 0 : EOF;
#else
        return EOF;
#endif
}

#ifdef DES
/*
 * get keyword from tty or stdin
 */
int
get_keyword(void)
{
        char *p;                /* used to obtain the key */
        Desbuf msgbuf;                  /* I/O buffer */

        /*
         * get the key
         */
        if (*(p = getpass("Enter key: "))) {

                /*
                 * copy it, nul-padded, into the key area
                 */
                expand_des_key(BUFFER(msgbuf), p);
                MEMZERO(p, _PASSWORD_LEN);
                set_des_key(msgbuf);
                MEMZERO(msgbuf, sizeof msgbuf);
                return 1;
        }
        return 0;
}


/*
 * print a warning message and, possibly, terminate
 */
static void
des_error(const char *s /* the message */)
{
        (void)sprintf(errmsg, "%s", s ? s : strerror(errno));
}

/*
 * map a hex character to an integer
 */
static int
hex_to_binary(int c /* char to be converted */,
              int radix /* base (2 to 16) */)
{
        switch(c) {
        case '0':               return(0x0);
        case '1':               return(0x1);
        case '2':               return(radix > 2 ? 0x2 : -1);
        case '3':               return(radix > 3 ? 0x3 : -1);
        case '4':               return(radix > 4 ? 0x4 : -1);
        case '5':               return(radix > 5 ? 0x5 : -1);
        case '6':               return(radix > 6 ? 0x6 : -1);
        case '7':               return(radix > 7 ? 0x7 : -1);
        case '8':               return(radix > 8 ? 0x8 : -1);
        case '9':               return(radix > 9 ? 0x9 : -1);
        case 'A': case 'a':     return(radix > 10 ? 0xa : -1);
        case 'B': case 'b':     return(radix > 11 ? 0xb : -1);
        case 'C': case 'c':     return(radix > 12 ? 0xc : -1);
        case 'D': case 'd':     return(radix > 13 ? 0xd : -1);
        case 'E': case 'e':     return(radix > 14 ? 0xe : -1);
        case 'F': case 'f':     return(radix > 15 ? 0xf : -1);
        }
        /*
         * invalid character
         */
        return(-1);
}

/*
 * convert the key to a bit pattern
 */
static void
expand_des_key(char *obuf /* bit pattern */, char *inbuf /* the key itself */)
{
        int i, j;                       /* counter in a for loop */
        int nbuf[64];                   /* used for hex/key translation */

        /*
         * leading '0x' or '0X' == hex key
         */
        if (inbuf[0] == '0' && (inbuf[1] == 'x' || inbuf[1] == 'X')) {
                inbuf = &inbuf[2];
                /*
                 * now translate it, bombing on any illegal hex digit
                 */
                for (i = 0; inbuf[i] && i < 16; i++)
                        if ((nbuf[i] = hex_to_binary((int) inbuf[i], 16)) == -1)
                                des_error("bad hex digit in key");
                while (i < 16)
                        nbuf[i++] = 0;
                for (i = 0; i < 8; i++)
                        obuf[i] =
                            ((nbuf[2*i]&0xf)<<4) | (nbuf[2*i+1]&0xf);
                /* preserve parity bits */
                pflag = 1;
                return;
        }
        /*
         * leading '0b' or '0B' == binary key
         */
        if (inbuf[0] == '0' && (inbuf[1] == 'b' || inbuf[1] == 'B')) {
                inbuf = &inbuf[2];
                /*
                 * now translate it, bombing on any illegal binary digit
                 */
                for (i = 0; inbuf[i] && i < 16; i++)
                        if ((nbuf[i] = hex_to_binary((int) inbuf[i], 2)) == -1)
                                des_error("bad binary digit in key");
                while (i < 64)
                        nbuf[i++] = 0;
                for (i = 0; i < 8; i++)
                        for (j = 0; j < 8; j++)
                                obuf[i] = (obuf[i]<<1)|nbuf[8*i+j];
                /* preserve parity bits */
                pflag = 1;
                return;
        }
        /*
         * no special leader -- ASCII
         */
        (void)strncpy(obuf, inbuf, 8);
}

/*****************
 * DES FUNCTIONS *
 *****************/
/*
 * This sets the DES key and (if you're using the deszip version)
 * the direction of the transformation.  This uses the Sun
 * to map the 64-bit key onto the 56 bits that the key schedule
 * generation routines use: the old way, which just uses the user-
 * supplied 64 bits as is, and the new way, which resets the parity
 * bit to be the same as the low-order bit in each character.  The
 * new way generates a greater variety of key schedules, since many
 * systems set the parity (high) bit of each character to 0, and the
 * DES ignores the low order bit of each character.
 */
static void
set_des_key(Desbuf buf /* key block */)
{
        int i, j;                               /* counter in a for loop */
        int par;                                /* parity counter */

        /*
         * if the parity is not preserved, flip it
         */
        if (!pflag) {
                for (i = 0; i < 8; i++) {
                        par = 0;
                        for (j = 1; j < 8; j++)
                                if ((bits[j]&UCHAR(buf, i)) != 0)
                                        par++;
                        if ((par&01) == 01)
                                UCHAR(buf, i) = UCHAR(buf, i)&0177;
                        else
                                UCHAR(buf, i) = (UCHAR(buf, i)&0177)|0200;
                }
        }

        DES_KEY(UBUFFER(buf));
}


/*
 * This encrypts using the Cipher Block Chaining mode of DES
 */
static int
cbc_encode(char *msgbuf, int n, FILE *fp)
{
        int inverse = 0;        /* 0 to encrypt, 1 to decrypt */

        /*
         * do the transformation
         */
        if (n == 8) {
                for (n = 0; n < 8; n++)
                        CHAR(msgbuf, n) ^= CHAR(ivec, n);
                DES_XFORM(UBUFFER(msgbuf));
                MEMCPY(BUFFER(ivec), BUFFER(msgbuf), 8);
                return WRITE(BUFFER(msgbuf), 8, fp);
        }
        /*
         * at EOF or last block -- in either case, the last byte contains
         * the character representation of the number of bytes in it
         */
/*
        MEMZERO(msgbuf +  n, 8 - n);
*/
        /*
         *  Pad the last block randomly
         */
        (void)MEMCPY(BUFFER(msgbuf + n), BUFFER(pvec), 8 - n);
        CHAR(msgbuf, 7) = n;
        for (n = 0; n < 8; n++)
                CHAR(msgbuf, n) ^= CHAR(ivec, n);
        DES_XFORM(UBUFFER(msgbuf));
        return WRITE(BUFFER(msgbuf), 8, fp);
}

/*
 * This decrypts using the Cipher Block Chaining mode of DES
 */
static int
cbc_decode(char *msgbuf /* I/O buffer */,
           FILE *fp /* input file descriptor */)
{
        Desbuf inbuf;   /* temp buffer for initialization vector */
        int n;          /* number of bytes actually read */
        int c;          /* used to test for EOF */
        int inverse = 1;        /* 0 to encrypt, 1 to decrypt */

        if ((n = READ(BUFFER(msgbuf), 8, fp)) == 8) {
                /*
                 * do the transformation
                 */
                MEMCPY(BUFFER(inbuf), BUFFER(msgbuf), 8);
                DES_XFORM(UBUFFER(msgbuf));
                for (c = 0; c < 8; c++)
                        UCHAR(msgbuf, c) ^= UCHAR(ivec, c);
                MEMCPY(BUFFER(ivec), BUFFER(inbuf), 8);
                /*
                 * if the last one, handle it specially
                 */
                if ((c = fgetc(fp)) == EOF) {
                        n = CHAR(msgbuf, 7);
                        if (n < 0 || n > 7) {
                                des_error("decryption failed (block corrupted)");
                                return EOF;
                        }
                } else
                        (void)ungetc(c, fp);
                return n;
        }
        if (n > 0)
                des_error("decryption failed (incomplete block)");
        else if (n < 0)
                des_error("cannot read file");
        return EOF;
}
#endif  /* DES */