428 lines
11 KiB
C
428 lines
11 KiB
C
/* 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.
|
|
*
|
|
* 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
|
|
* $Id: cbc.c,v 1.6 1996/08/11 16:48:11 ache Exp $
|
|
*/
|
|
|
|
#ifndef lint
|
|
static char * const rcsid = "@(#)cbc.c,v 1.2 1994/02/01 00:34:36 alm Exp";
|
|
#endif /* not lint */
|
|
|
|
#include <sys/types.h>
|
|
#include <errno.h>
|
|
#include <pwd.h>
|
|
|
|
#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)
|
|
|
|
/*
|
|
* global variables and related macros
|
|
*/
|
|
|
|
enum { /* encrypt, decrypt, authenticate */
|
|
MODE_ENCRYPT, MODE_DECRYPT, MODE_AUTHENTICATE
|
|
} mode = MODE_ENCRYPT;
|
|
|
|
Desbuf ivec; /* initialization vector */
|
|
Desbuf pvec; /* padding vector */
|
|
char bits[] = { /* used to extract bits from a char */
|
|
'\200', '\100', '\040', '\020', '\010', '\004', '\002', '\001'
|
|
};
|
|
int pflag; /* 1 to preserve parity bits */
|
|
|
|
unsigned char des_buf[8]; /* shared buffer for get_des_char/put_des_char */
|
|
int des_ct = 0; /* count for get_des_char/put_des_char */
|
|
int des_n = 0; /* index for put_des_char/get_des_char */
|
|
|
|
|
|
/* init_des_cipher: initialize DES */
|
|
void
|
|
init_des_cipher()
|
|
{
|
|
#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(fp)
|
|
FILE *fp;
|
|
{
|
|
#ifdef DES
|
|
if (des_n >= des_ct) {
|
|
des_n = 0;
|
|
des_ct = cbc_decode(des_buf, fp);
|
|
}
|
|
return (des_ct > 0) ? des_buf[des_n++] : EOF;
|
|
#else
|
|
return (getc(fp));
|
|
#endif
|
|
}
|
|
|
|
|
|
/* put_des_char: write a char to an encrypted file; return char written */
|
|
int
|
|
put_des_char(c, fp)
|
|
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) ? (des_buf[des_n++] = c) : EOF;
|
|
#else
|
|
return (fputc(c, fp));
|
|
#endif
|
|
}
|
|
|
|
|
|
/* flush_des_file: flush an encrypted file's output; return status */
|
|
int
|
|
flush_des_file(fp)
|
|
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 (fflush(fp));
|
|
#endif
|
|
}
|
|
|
|
#ifdef DES
|
|
/*
|
|
* get keyword from tty or stdin
|
|
*/
|
|
int
|
|
get_keyword()
|
|
{
|
|
register 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
|
|
*/
|
|
void
|
|
des_error(s)
|
|
char *s; /* the message */
|
|
{
|
|
(void)sprintf(errmsg, "%s", s ? s : strerror(errno));
|
|
}
|
|
|
|
/*
|
|
* map a hex character to an integer
|
|
*/
|
|
int
|
|
hex_to_binary(c, radix)
|
|
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
|
|
*/
|
|
void
|
|
expand_des_key(obuf, ibuf)
|
|
char *obuf; /* bit pattern */
|
|
char *ibuf; /* the key itself */
|
|
{
|
|
register int i, j; /* counter in a for loop */
|
|
int nbuf[64]; /* used for hex/key translation */
|
|
|
|
/*
|
|
* leading '0x' or '0X' == hex key
|
|
*/
|
|
if (ibuf[0] == '0' && (ibuf[1] == 'x' || ibuf[1] == 'X')) {
|
|
ibuf = &ibuf[2];
|
|
/*
|
|
* now translate it, bombing on any illegal hex digit
|
|
*/
|
|
for (i = 0; ibuf[i] && i < 16; i++)
|
|
if ((nbuf[i] = hex_to_binary((int) ibuf[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 (ibuf[0] == '0' && (ibuf[1] == 'b' || ibuf[1] == 'B')) {
|
|
ibuf = &ibuf[2];
|
|
/*
|
|
* now translate it, bombing on any illegal binary digit
|
|
*/
|
|
for (i = 0; ibuf[i] && i < 16; i++)
|
|
if ((nbuf[i] = hex_to_binary((int) ibuf[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, ibuf, 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.
|
|
*/
|
|
void
|
|
set_des_key(buf)
|
|
Desbuf buf; /* key block */
|
|
{
|
|
register int i, j; /* counter in a for loop */
|
|
register 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
|
|
*/
|
|
int
|
|
cbc_encode(msgbuf, n, fp)
|
|
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
|
|
*/
|
|
int
|
|
cbc_decode(msgbuf, fp)
|
|
char *msgbuf; /* I/O buffer */
|
|
FILE *fp; /* input file descriptor */
|
|
{
|
|
Desbuf ibuf; /* temp buffer for initialization vector */
|
|
register int n; /* number of bytes actually read */
|
|
register 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(ibuf), BUFFER(msgbuf), 8);
|
|
DES_XFORM(UBUFFER(msgbuf));
|
|
for (c = 0; c < 8; c++)
|
|
UCHAR(msgbuf, c) ^= UCHAR(ivec, c);
|
|
MEMCPY(BUFFER(ivec), BUFFER(ibuf), 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 */
|