7e6cabd06e
Renumber cluase 4 to 3, per what everybody else did when BSD granted them permission to remove clause 3. My insistance on keeping the same numbering for legal reasons is too pedantic, so give up on that point. Submitted by: Jan Schaumann <jschauma@stevens.edu> Pull Request: https://github.com/freebsd/freebsd/pull/96
394 lines
9.7 KiB
C
394 lines
9.7 KiB
C
/* cbc.c: This file contains the encryption routines for the ed line editor */
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/*-
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* Copyright (c) 1993 The Regents of the University of California.
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* All rights reserved.
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*
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* Copyright (c) 1993 Andrew Moore, Talke Studio.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <errno.h>
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#include <pwd.h>
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#ifdef DES
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#include <time.h>
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#include <openssl/des.h>
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#define ED_DES_INCLUDES
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#endif
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#include "ed.h"
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/*
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* BSD and System V systems offer special library calls that do
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* block move_liness and fills, so if possible we take advantage of them
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*/
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#define MEMCPY(dest,src,len) memcpy((dest),(src),(len))
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#define MEMZERO(dest,len) memset((dest), 0, (len))
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/* Hide the calls to the primitive encryption routines. */
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#define DES_XFORM(buf) \
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DES_ecb_encrypt(buf, buf, &schedule, \
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inverse ? DES_DECRYPT : DES_ENCRYPT);
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/*
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* read/write - no error checking
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*/
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#define READ(buf, n, fp) fread(buf, sizeof(char), n, fp)
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#define WRITE(buf, n, fp) fwrite(buf, sizeof(char), n, fp)
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/*
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* global variables and related macros
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*/
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#ifdef DES
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static DES_cblock ivec; /* initialization vector */
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static DES_cblock pvec; /* padding vector */
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static char bits[] = { /* used to extract bits from a char */
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'\200', '\100', '\040', '\020', '\010', '\004', '\002', '\001'
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};
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static int pflag; /* 1 to preserve parity bits */
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static DES_key_schedule schedule; /* expanded DES key */
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static unsigned char des_buf[8];/* shared buffer for get_des_char/put_des_char */
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static int des_ct = 0; /* count for get_des_char/put_des_char */
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static int des_n = 0; /* index for put_des_char/get_des_char */
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#endif
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/* init_des_cipher: initialize DES */
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void
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init_des_cipher(void)
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{
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#ifdef DES
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des_ct = des_n = 0;
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/* initialize the initialization vector */
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MEMZERO(ivec, 8);
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/* initialize the padding vector */
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arc4random_buf(pvec, sizeof(pvec));
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#endif
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}
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/* get_des_char: return next char in an encrypted file */
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int
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get_des_char(FILE *fp)
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{
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#ifdef DES
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if (des_n >= des_ct) {
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des_n = 0;
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des_ct = cbc_decode(des_buf, fp);
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}
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return (des_ct > 0) ? des_buf[des_n++] : EOF;
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#else
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return (getc(fp));
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#endif
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}
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/* put_des_char: write a char to an encrypted file; return char written */
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int
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put_des_char(int c, FILE *fp)
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{
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#ifdef DES
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if (des_n == sizeof des_buf) {
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des_ct = cbc_encode(des_buf, des_n, fp);
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des_n = 0;
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}
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return (des_ct >= 0) ? (des_buf[des_n++] = c) : EOF;
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#else
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return (fputc(c, fp));
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#endif
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}
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/* flush_des_file: flush an encrypted file's output; return status */
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int
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flush_des_file(FILE *fp)
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{
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#ifdef DES
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if (des_n == sizeof des_buf) {
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des_ct = cbc_encode(des_buf, des_n, fp);
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des_n = 0;
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}
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return (des_ct >= 0 && cbc_encode(des_buf, des_n, fp) >= 0) ? 0 : EOF;
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#else
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return (fflush(fp));
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#endif
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}
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#ifdef DES
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/*
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* get keyword from tty or stdin
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*/
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int
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get_keyword(void)
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{
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char *p; /* used to obtain the key */
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DES_cblock msgbuf; /* I/O buffer */
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/*
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* get the key
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*/
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if ((p = getpass("Enter key: ")) != NULL && *p != '\0') {
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/*
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* copy it, nul-padded, into the key area
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*/
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expand_des_key(msgbuf, p);
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MEMZERO(p, _PASSWORD_LEN);
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set_des_key(&msgbuf);
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MEMZERO(msgbuf, sizeof msgbuf);
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return 1;
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}
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return 0;
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}
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/*
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* print a warning message and, possibly, terminate
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*/
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void
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des_error(const char *s)
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{
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errmsg = s ? s : strerror(errno);
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}
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/*
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* map a hex character to an integer
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*/
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int
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hex_to_binary(int c, int radix)
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{
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switch(c) {
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case '0': return(0x0);
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case '1': return(0x1);
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case '2': return(radix > 2 ? 0x2 : -1);
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case '3': return(radix > 3 ? 0x3 : -1);
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case '4': return(radix > 4 ? 0x4 : -1);
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case '5': return(radix > 5 ? 0x5 : -1);
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case '6': return(radix > 6 ? 0x6 : -1);
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case '7': return(radix > 7 ? 0x7 : -1);
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case '8': return(radix > 8 ? 0x8 : -1);
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case '9': return(radix > 9 ? 0x9 : -1);
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case 'A': case 'a': return(radix > 10 ? 0xa : -1);
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case 'B': case 'b': return(radix > 11 ? 0xb : -1);
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case 'C': case 'c': return(radix > 12 ? 0xc : -1);
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case 'D': case 'd': return(radix > 13 ? 0xd : -1);
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case 'E': case 'e': return(radix > 14 ? 0xe : -1);
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case 'F': case 'f': return(radix > 15 ? 0xf : -1);
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}
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/*
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* invalid character
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*/
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return(-1);
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}
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/*
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* convert the key to a bit pattern
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* obuf bit pattern
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* kbuf the key itself
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*/
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void
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expand_des_key(char *obuf, char *kbuf)
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{
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int i, j; /* counter in a for loop */
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int nbuf[64]; /* used for hex/key translation */
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/*
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* leading '0x' or '0X' == hex key
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*/
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if (kbuf[0] == '0' && (kbuf[1] == 'x' || kbuf[1] == 'X')) {
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kbuf = &kbuf[2];
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/*
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* now translate it, bombing on any illegal hex digit
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*/
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for (i = 0; i < 16 && kbuf[i]; i++)
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if ((nbuf[i] = hex_to_binary((int) kbuf[i], 16)) == -1)
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des_error("bad hex digit in key");
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while (i < 16)
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nbuf[i++] = 0;
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for (i = 0; i < 8; i++)
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obuf[i] =
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((nbuf[2*i]&0xf)<<4) | (nbuf[2*i+1]&0xf);
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/* preserve parity bits */
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pflag = 1;
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return;
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}
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/*
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* leading '0b' or '0B' == binary key
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*/
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if (kbuf[0] == '0' && (kbuf[1] == 'b' || kbuf[1] == 'B')) {
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kbuf = &kbuf[2];
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/*
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* now translate it, bombing on any illegal binary digit
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*/
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for (i = 0; i < 16 && kbuf[i]; i++)
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if ((nbuf[i] = hex_to_binary((int) kbuf[i], 2)) == -1)
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des_error("bad binary digit in key");
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while (i < 64)
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nbuf[i++] = 0;
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for (i = 0; i < 8; i++)
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for (j = 0; j < 8; j++)
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obuf[i] = (obuf[i]<<1)|nbuf[8*i+j];
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/* preserve parity bits */
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pflag = 1;
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return;
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}
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/*
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* no special leader -- ASCII
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*/
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(void)strncpy(obuf, kbuf, 8);
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}
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/*****************
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* DES FUNCTIONS *
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*****************/
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/*
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* This sets the DES key and (if you're using the deszip version)
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* the direction of the transformation. This uses the Sun
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* to map the 64-bit key onto the 56 bits that the key schedule
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* generation routines use: the old way, which just uses the user-
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* supplied 64 bits as is, and the new way, which resets the parity
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* bit to be the same as the low-order bit in each character. The
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* new way generates a greater variety of key schedules, since many
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* systems set the parity (high) bit of each character to 0, and the
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* DES ignores the low order bit of each character.
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*/
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void
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set_des_key(DES_cblock *buf) /* key block */
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{
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int i, j; /* counter in a for loop */
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int par; /* parity counter */
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/*
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* if the parity is not preserved, flip it
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*/
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if (!pflag) {
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for (i = 0; i < 8; i++) {
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par = 0;
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for (j = 1; j < 8; j++)
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if ((bits[j] & (*buf)[i]) != 0)
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par++;
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if ((par & 0x01) == 0x01)
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(*buf)[i] &= 0x7f;
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else
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(*buf)[i] = ((*buf)[i] & 0x7f) | 0x80;
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}
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}
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DES_set_odd_parity(buf);
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DES_set_key(buf, &schedule);
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}
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/*
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* This encrypts using the Cipher Block Chaining mode of DES
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*/
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int
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cbc_encode(unsigned char *msgbuf, int n, FILE *fp)
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{
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int inverse = 0; /* 0 to encrypt, 1 to decrypt */
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/*
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* do the transformation
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*/
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if (n == 8) {
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for (n = 0; n < 8; n++)
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msgbuf[n] ^= ivec[n];
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DES_XFORM((DES_cblock *)msgbuf);
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MEMCPY(ivec, msgbuf, 8);
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return WRITE(msgbuf, 8, fp);
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}
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/*
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* at EOF or last block -- in either case, the last byte contains
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* the character representation of the number of bytes in it
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*/
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/*
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MEMZERO(msgbuf + n, 8 - n);
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*/
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/*
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* Pad the last block randomly
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*/
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(void)MEMCPY(msgbuf + n, pvec, 8 - n);
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msgbuf[7] = n;
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for (n = 0; n < 8; n++)
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msgbuf[n] ^= ivec[n];
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DES_XFORM((DES_cblock *)msgbuf);
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return WRITE(msgbuf, 8, fp);
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}
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/*
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* This decrypts using the Cipher Block Chaining mode of DES
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* msgbuf I/O buffer
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* fp input file descriptor
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*/
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int
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cbc_decode(unsigned char *msgbuf, FILE *fp)
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{
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DES_cblock tbuf; /* temp buffer for initialization vector */
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int n; /* number of bytes actually read */
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int c; /* used to test for EOF */
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int inverse = 1; /* 0 to encrypt, 1 to decrypt */
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if ((n = READ(msgbuf, 8, fp)) == 8) {
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/*
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* do the transformation
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*/
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MEMCPY(tbuf, msgbuf, 8);
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DES_XFORM((DES_cblock *)msgbuf);
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for (c = 0; c < 8; c++)
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msgbuf[c] ^= ivec[c];
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MEMCPY(ivec, tbuf, 8);
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/*
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* if the last one, handle it specially
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*/
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if ((c = fgetc(fp)) == EOF) {
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n = msgbuf[7];
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if (n < 0 || n > 7) {
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des_error("decryption failed (block corrupted)");
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return EOF;
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}
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} else
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(void)ungetc(c, fp);
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return n;
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}
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if (n > 0)
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des_error("decryption failed (incomplete block)");
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else if (n < 0)
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des_error("cannot read file");
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return EOF;
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}
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#endif /* DES */
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