FreeBSD-5.3/bin/ed/cbc.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.
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/bin/ed/cbc.c,v 1.20 2004/04/06 20:06:47 markm Exp $");
#include <sys/types.h>
#include <errno.h>
#include <pwd.h>
#ifdef DES
#include <time.h>
#include <openssl/des.h>
#define ED_DES_INCLUDES
#endif
#include "ed.h"
/*
* 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_XFORM(buf) \
DES_ecb_encrypt(buf, buf, &schedule, \
inverse ? DES_DECRYPT : DES_ENCRYPT);
/*
* 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)
/*
* global variables and related macros
*/
enum { /* encrypt, decrypt, authenticate */
MODE_ENCRYPT, MODE_DECRYPT, MODE_AUTHENTICATE
} mode = MODE_ENCRYPT;
#ifdef DES
DES_cblock ivec; /* initialization vector */
DES_cblock pvec; /* padding vector */
#endif
char bits[] = { /* used to extract bits from a char */
'\200', '\100', '\040', '\020', '\010', '\004', '\002', '\001'
};
int pflag; /* 1 to preserve parity bits */
#ifdef DES
DES_key_schedule schedule; /* expanded DES key */
#endif
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(void)
{
#ifdef DES
int i;
des_ct = des_n = 0;
/* initialize the initialization vector */
MEMZERO(ivec, 8);
/* initialize the padding vector */
for (i = 0; i < 8; i++)
pvec[i] = (char) (arc4random() % 256);
#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) ? 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(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(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(void)
{
char *p; /* used to obtain the key */
DES_cblock msgbuf; /* I/O buffer */
/*
* get the key
*/
if (*(p = getpass("Enter key: "))) {
/*
* copy it, nul-padded, into the key area
*/
expand_des_key(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(const char *s)
{
errmsg = s ? s : strerror(errno);
}
/*
* map a hex character to an integer
*/
int
hex_to_binary(int c, int radix)
{
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
* obuf bit pattern
* kbuf the key itself
*/
void
expand_des_key(char *obuf, char *kbuf)
{
int i, j; /* counter in a for loop */
int nbuf[64]; /* used for hex/key translation */
/*
* leading '0x' or '0X' == hex key
*/
if (kbuf[0] == '0' && (kbuf[1] == 'x' || kbuf[1] == 'X')) {
kbuf = &kbuf[2];
/*
* now translate it, bombing on any illegal hex digit
*/
for (i = 0; kbuf[i] && i < 16; i++)
if ((nbuf[i] = hex_to_binary((int) kbuf[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 (kbuf[0] == '0' && (kbuf[1] == 'b' || kbuf[1] == 'B')) {
kbuf = &kbuf[2];
/*
* now translate it, bombing on any illegal binary digit
*/
for (i = 0; kbuf[i] && i < 16; i++)
if ((nbuf[i] = hex_to_binary((int) kbuf[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, kbuf, 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(DES_cblock *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] & (*buf)[i]) != 0)
par++;
if ((par & 0x01) == 0x01)
(*buf)[i] &= 0x7f;
else
(*buf)[i] = ((*buf)[i] & 0x7f) | 0x80;
}
}
DES_set_odd_parity(buf);
DES_set_key(buf, &schedule);
}
/*
* This encrypts using the Cipher Block Chaining mode of DES
*/
int
cbc_encode(unsigned 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++)
msgbuf[n] ^= ivec[n];
DES_XFORM((DES_cblock *)msgbuf);
MEMCPY(ivec, msgbuf, 8);
return WRITE(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(msgbuf + n, pvec, 8 - n);
msgbuf[7] = n;
for (n = 0; n < 8; n++)
msgbuf[n] ^= ivec[n];
DES_XFORM((DES_cblock *)msgbuf);
return WRITE(msgbuf, 8, fp);
}
/*
* This decrypts using the Cipher Block Chaining mode of DES
* msgbuf I/O buffer
* fp input file descriptor
*/
int
cbc_decode(unsigned char *msgbuf, FILE *fp)
{
DES_cblock tbuf; /* 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(msgbuf, 8, fp)) == 8) {
/*
* do the transformation
*/
MEMCPY(tbuf, msgbuf, 8);
DES_XFORM((DES_cblock *)msgbuf);
for (c = 0; c < 8; c++)
msgbuf[c] ^= ivec[c];
MEMCPY(ivec, tbuf, 8);
/*
* if the last one, handle it specially
*/
if ((c = fgetc(fp)) == EOF) {
n = 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 */