cbc.c revision 7165
116Salm/* cbc.c: This file contains the encryption routines for the ed line editor */ 216Salm/*- 31057Salm * Copyright (c) 1993 The Regents of the University of California. 416Salm * All rights reserved. 516Salm * 61057Salm * Copyright (c) 1993 Andrew Moore, Talke Studio. 71057Salm * All rights reserved. 816Salm * 916Salm * Redistribution and use in source and binary forms, with or without 1016Salm * modification, are permitted provided that the following conditions 1116Salm * are met: 1216Salm * 1. Redistributions of source code must retain the above copyright 1316Salm * notice, this list of conditions and the following disclaimer. 1416Salm * 2. Redistributions in binary form must reproduce the above copyright 1516Salm * notice, this list of conditions and the following disclaimer in the 1616Salm * documentation and/or other materials provided with the distribution. 1716Salm * 3. All advertising materials mentioning features or use of this software 1816Salm * must display the following acknowledgement: 1916Salm * This product includes software developed by the University of 2016Salm * California, Berkeley and its contributors. 2116Salm * 4. Neither the name of the University nor the names of its contributors 2216Salm * may be used to endorse or promote products derived from this software 2316Salm * without specific prior written permission. 2416Salm * 2516Salm * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 2616Salm * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 2716Salm * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2816Salm * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 2916Salm * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 3016Salm * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 3116Salm * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 3216Salm * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 3316Salm * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 3416Salm * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 3516Salm * SUCH DAMAGE. 361057Salm * 371057Salm * from: @(#)bdes.c 5.5 (Berkeley) 6/27/91 387165Sjoerg * $Id: cbc.c,v 1.4 1994/09/24 02:55:24 davidg Exp $ 3916Salm */ 4016Salm 4116Salm#ifndef lint 421297Salmstatic char *rcsid = "@(#)cbc.c,v 1.2 1994/02/01 00:34:36 alm Exp"; 4316Salm#endif /* not lint */ 4416Salm 451057Salm#include <sys/types.h> 461057Salm#include <ctype.h> 4716Salm#include <errno.h> 4816Salm#include <pwd.h> 4916Salm 5016Salm#include "ed.h" 5116Salm 521057Salm 5316Salm/* 5416Salm * Define a divisor for rand() that yields a uniform distribution in the 5516Salm * range 0-255. 5616Salm */ 5716Salm#define RAND_DIV (((unsigned) RAND_MAX + 1) >> 8) 5816Salm 5916Salm/* 6016Salm * BSD and System V systems offer special library calls that do 611057Salm * block move_liness and fills, so if possible we take advantage of them 6216Salm */ 6316Salm#define MEMCPY(dest,src,len) memcpy((dest),(src),(len)) 6416Salm#define MEMZERO(dest,len) memset((dest), 0, (len)) 6516Salm 6616Salm/* Hide the calls to the primitive encryption routines. */ 6716Salm#define DES_KEY(buf) \ 6816Salm if (des_setkey(buf)) \ 691057Salm des_error("des_setkey"); 7016Salm#define DES_XFORM(buf) \ 7116Salm if (des_cipher(buf, buf, 0L, (inverse ? -1 : 1))) \ 721057Salm des_error("des_cipher"); 7316Salm 7416Salm/* 7516Salm * read/write - no error checking 7616Salm */ 7716Salm#define READ(buf, n, fp) fread(buf, sizeof(char), n, fp) 7816Salm#define WRITE(buf, n, fp) fwrite(buf, sizeof(char), n, fp) 7916Salm 8016Salm/* 8116Salm * some things to make references easier 8216Salm */ 8316Salmtypedef char Desbuf[8]; 8416Salm#define CHAR(x,i) (x[i]) 8516Salm#define UCHAR(x,i) (x[i]) 8616Salm#define BUFFER(x) (x) 8716Salm#define UBUFFER(x) (x) 8816Salm 8916Salm/* 9016Salm * global variables and related macros 9116Salm */ 9216Salm 9316Salmenum { /* encrypt, decrypt, authenticate */ 9416Salm MODE_ENCRYPT, MODE_DECRYPT, MODE_AUTHENTICATE 9516Salm} mode = MODE_ENCRYPT; 9616Salm 9716SalmDesbuf ivec; /* initialization vector */ 9816SalmDesbuf pvec; /* padding vector */ 9916Salmchar bits[] = { /* used to extract bits from a char */ 10016Salm '\200', '\100', '\040', '\020', '\010', '\004', '\002', '\001' 10116Salm}; 10216Salmint pflag; /* 1 to preserve parity bits */ 10316Salm 1041057Salmunsigned char des_buf[8]; /* shared buffer for get_des_char/put_des_char */ 1051057Salmint des_ct = 0; /* count for get_des_char/put_des_char */ 1061057Salmint des_n = 0; /* index for put_des_char/get_des_char */ 10716Salm 10816Salm 1091057Salm/* init_des_cipher: initialize DES */ 11016Salmvoid 1111057Salminit_des_cipher() 11216Salm{ 11316Salm#ifdef DES 11416Salm int i; 11516Salm 11616Salm des_ct = des_n = 0; 11716Salm 1187165Sjoerg /* initialize the initialization vector */ 11916Salm MEMZERO(ivec, 8); 12016Salm 12116Salm /* intialize the padding vector */ 12216Salm srand((unsigned) time((time_t *) 0)); 12316Salm for (i = 0; i < 8; i++) 12416Salm CHAR(pvec, i) = (char) (rand()/RAND_DIV); 12516Salm#endif 12616Salm} 12716Salm 12816Salm 1291057Salm/* get_des_char: return next char in an encrypted file */ 1301057Salmint 1311057Salmget_des_char(fp) 13216Salm FILE *fp; 13316Salm{ 13416Salm#ifdef DES 13516Salm if (des_n >= des_ct) { 13616Salm des_n = 0; 1371057Salm des_ct = cbc_decode(des_buf, fp); 13816Salm } 13916Salm return (des_ct > 0) ? des_buf[des_n++] : EOF; 1407165Sjoerg#else 1417165Sjoerg return (getc(fp)); 14216Salm#endif 14316Salm} 14416Salm 14516Salm 1461057Salm/* put_des_char: write a char to an encrypted file; return char written */ 1471057Salmint 1481057Salmput_des_char(c, fp) 14916Salm int c; 15016Salm FILE *fp; 15116Salm{ 15216Salm#ifdef DES 15316Salm if (des_n == sizeof des_buf) { 1541057Salm des_ct = cbc_encode(des_buf, des_n, fp); 15516Salm des_n = 0; 15616Salm } 15716Salm return (des_ct >= 0) ? (des_buf[des_n++] = c) : EOF; 1587165Sjoerg#else 1597165Sjoerg return (fputc(c, fp)); 16016Salm#endif 16116Salm} 16216Salm 16316Salm 1641057Salm/* flush_des_file: flush an encrypted file's output; return status */ 1651057Salmint 1661057Salmflush_des_file(fp) 16716Salm FILE *fp; 16816Salm{ 16916Salm#ifdef DES 17016Salm if (des_n == sizeof des_buf) { 1711057Salm des_ct = cbc_encode(des_buf, des_n, fp); 17216Salm des_n = 0; 17316Salm } 1741057Salm return (des_ct >= 0 && cbc_encode(des_buf, des_n, fp) >= 0) ? 0 : EOF; 1757165Sjoerg#else 1767165Sjoerg return (fflush(fp)); 17716Salm#endif 17816Salm} 17916Salm 18016Salm#ifdef DES 18116Salm/* 18216Salm * get keyword from tty or stdin 18316Salm */ 1841057Salmint 1851057Salmget_keyword() 18616Salm{ 18716Salm register char *p; /* used to obtain the key */ 18816Salm Desbuf msgbuf; /* I/O buffer */ 18916Salm 19016Salm /* 19116Salm * get the key 19216Salm */ 19316Salm if (*(p = getpass("Enter key: "))) { 19416Salm 19516Salm /* 19616Salm * copy it, nul-padded, into the key area 19716Salm */ 1981057Salm expand_des_key(BUFFER(msgbuf), p); 19916Salm MEMZERO(p, _PASSWORD_LEN); 2001057Salm set_des_key(msgbuf); 20116Salm MEMZERO(msgbuf, sizeof msgbuf); 20216Salm return 1; 20316Salm } 20416Salm return 0; 20516Salm} 20616Salm 20716Salm 20816Salm/* 20916Salm * print a warning message and, possibly, terminate 21016Salm */ 21116Salmvoid 2121057Salmdes_error(s) 21316Salm char *s; /* the message */ 21416Salm{ 21516Salm (void)sprintf(errmsg, "%s", s ? s : strerror(errno)); 21616Salm} 21716Salm 21816Salm/* 21916Salm * map a hex character to an integer 22016Salm */ 2211057Salmint 2221057Salmhex_to_binary(c, radix) 22316Salm int c; /* char to be converted */ 22416Salm int radix; /* base (2 to 16) */ 22516Salm{ 22616Salm switch(c) { 22716Salm case '0': return(0x0); 22816Salm case '1': return(0x1); 22916Salm case '2': return(radix > 2 ? 0x2 : -1); 23016Salm case '3': return(radix > 3 ? 0x3 : -1); 23116Salm case '4': return(radix > 4 ? 0x4 : -1); 23216Salm case '5': return(radix > 5 ? 0x5 : -1); 23316Salm case '6': return(radix > 6 ? 0x6 : -1); 23416Salm case '7': return(radix > 7 ? 0x7 : -1); 23516Salm case '8': return(radix > 8 ? 0x8 : -1); 23616Salm case '9': return(radix > 9 ? 0x9 : -1); 23716Salm case 'A': case 'a': return(radix > 10 ? 0xa : -1); 23816Salm case 'B': case 'b': return(radix > 11 ? 0xb : -1); 23916Salm case 'C': case 'c': return(radix > 12 ? 0xc : -1); 24016Salm case 'D': case 'd': return(radix > 13 ? 0xd : -1); 24116Salm case 'E': case 'e': return(radix > 14 ? 0xe : -1); 24216Salm case 'F': case 'f': return(radix > 15 ? 0xf : -1); 24316Salm } 24416Salm /* 24516Salm * invalid character 24616Salm */ 24716Salm return(-1); 24816Salm} 24916Salm 25016Salm/* 25116Salm * convert the key to a bit pattern 25216Salm */ 25316Salmvoid 2541057Salmexpand_des_key(obuf, ibuf) 25516Salm char *obuf; /* bit pattern */ 25616Salm char *ibuf; /* the key itself */ 25716Salm{ 25816Salm register int i, j; /* counter in a for loop */ 25916Salm int nbuf[64]; /* used for hex/key translation */ 26016Salm 26116Salm /* 26216Salm * leading '0x' or '0X' == hex key 26316Salm */ 26416Salm if (ibuf[0] == '0' && (ibuf[1] == 'x' || ibuf[1] == 'X')) { 26516Salm ibuf = &ibuf[2]; 26616Salm /* 26716Salm * now translate it, bombing on any illegal hex digit 26816Salm */ 26916Salm for (i = 0; ibuf[i] && i < 16; i++) 2701057Salm if ((nbuf[i] = hex_to_binary((int) ibuf[i], 16)) == -1) 2711057Salm des_error("bad hex digit in key"); 27216Salm while (i < 16) 27316Salm nbuf[i++] = 0; 27416Salm for (i = 0; i < 8; i++) 27516Salm obuf[i] = 27616Salm ((nbuf[2*i]&0xf)<<4) | (nbuf[2*i+1]&0xf); 27716Salm /* preserve parity bits */ 27816Salm pflag = 1; 27916Salm return; 28016Salm } 28116Salm /* 28216Salm * leading '0b' or '0B' == binary key 28316Salm */ 28416Salm if (ibuf[0] == '0' && (ibuf[1] == 'b' || ibuf[1] == 'B')) { 28516Salm ibuf = &ibuf[2]; 28616Salm /* 28716Salm * now translate it, bombing on any illegal binary digit 28816Salm */ 28916Salm for (i = 0; ibuf[i] && i < 16; i++) 2901057Salm if ((nbuf[i] = hex_to_binary((int) ibuf[i], 2)) == -1) 2911057Salm des_error("bad binary digit in key"); 29216Salm while (i < 64) 29316Salm nbuf[i++] = 0; 29416Salm for (i = 0; i < 8; i++) 29516Salm for (j = 0; j < 8; j++) 29616Salm obuf[i] = (obuf[i]<<1)|nbuf[8*i+j]; 29716Salm /* preserve parity bits */ 29816Salm pflag = 1; 29916Salm return; 30016Salm } 30116Salm /* 30216Salm * no special leader -- ASCII 30316Salm */ 30416Salm (void)strncpy(obuf, ibuf, 8); 30516Salm} 30616Salm 30716Salm/***************** 30816Salm * DES FUNCTIONS * 30916Salm *****************/ 31016Salm/* 31116Salm * This sets the DES key and (if you're using the deszip version) 31216Salm * the direction of the transformation. This uses the Sun 31316Salm * to map the 64-bit key onto the 56 bits that the key schedule 31416Salm * generation routines use: the old way, which just uses the user- 31516Salm * supplied 64 bits as is, and the new way, which resets the parity 31616Salm * bit to be the same as the low-order bit in each character. The 31716Salm * new way generates a greater variety of key schedules, since many 31816Salm * systems set the parity (high) bit of each character to 0, and the 31916Salm * DES ignores the low order bit of each character. 32016Salm */ 32116Salmvoid 3221057Salmset_des_key(buf) 32316Salm Desbuf buf; /* key block */ 32416Salm{ 32516Salm register int i, j; /* counter in a for loop */ 32616Salm register int par; /* parity counter */ 32716Salm 32816Salm /* 32916Salm * if the parity is not preserved, flip it 33016Salm */ 33116Salm if (!pflag) { 33216Salm for (i = 0; i < 8; i++) { 33316Salm par = 0; 33416Salm for (j = 1; j < 8; j++) 33516Salm if ((bits[j]&UCHAR(buf, i)) != 0) 33616Salm par++; 33716Salm if ((par&01) == 01) 33816Salm UCHAR(buf, i) = UCHAR(buf, i)&0177; 33916Salm else 34016Salm UCHAR(buf, i) = (UCHAR(buf, i)&0177)|0200; 34116Salm } 34216Salm } 34316Salm 34416Salm DES_KEY(UBUFFER(buf)); 34516Salm} 34616Salm 34716Salm 34816Salm/* 34916Salm * This encrypts using the Cipher Block Chaining mode of DES 35016Salm */ 3511057Salmint 3521057Salmcbc_encode(msgbuf, n, fp) 35316Salm char *msgbuf; 35416Salm int n; 35516Salm FILE *fp; 35616Salm{ 35716Salm int inverse = 0; /* 0 to encrypt, 1 to decrypt */ 35816Salm 35916Salm /* 36016Salm * do the transformation 36116Salm */ 36216Salm if (n == 8) { 36316Salm for (n = 0; n < 8; n++) 36416Salm CHAR(msgbuf, n) ^= CHAR(ivec, n); 36516Salm DES_XFORM(UBUFFER(msgbuf)); 36616Salm MEMCPY(BUFFER(ivec), BUFFER(msgbuf), 8); 36716Salm return WRITE(BUFFER(msgbuf), 8, fp); 36816Salm } 36916Salm /* 37016Salm * at EOF or last block -- in either case, the last byte contains 37116Salm * the character representation of the number of bytes in it 37216Salm */ 37316Salm/* 37416Salm MEMZERO(msgbuf + n, 8 - n); 37516Salm*/ 37616Salm /* 37716Salm * Pad the last block randomly 37816Salm */ 37916Salm (void)MEMCPY(BUFFER(msgbuf + n), BUFFER(pvec), 8 - n); 38016Salm CHAR(msgbuf, 7) = n; 38116Salm for (n = 0; n < 8; n++) 38216Salm CHAR(msgbuf, n) ^= CHAR(ivec, n); 38316Salm DES_XFORM(UBUFFER(msgbuf)); 38416Salm return WRITE(BUFFER(msgbuf), 8, fp); 38516Salm} 38616Salm 38716Salm/* 38816Salm * This decrypts using the Cipher Block Chaining mode of DES 38916Salm */ 3901057Salmint 3911057Salmcbc_decode(msgbuf, fp) 39216Salm char *msgbuf; /* I/O buffer */ 39316Salm FILE *fp; /* input file descriptor */ 39416Salm{ 39516Salm Desbuf ibuf; /* temp buffer for initialization vector */ 39616Salm register int n; /* number of bytes actually read */ 39716Salm register int c; /* used to test for EOF */ 39816Salm int inverse = 1; /* 0 to encrypt, 1 to decrypt */ 39916Salm 40016Salm if ((n = READ(BUFFER(msgbuf), 8, fp)) == 8) { 40116Salm /* 40216Salm * do the transformation 40316Salm */ 40416Salm MEMCPY(BUFFER(ibuf), BUFFER(msgbuf), 8); 40516Salm DES_XFORM(UBUFFER(msgbuf)); 40616Salm for (c = 0; c < 8; c++) 40716Salm UCHAR(msgbuf, c) ^= UCHAR(ivec, c); 40816Salm MEMCPY(BUFFER(ivec), BUFFER(ibuf), 8); 40916Salm /* 41016Salm * if the last one, handle it specially 41116Salm */ 41216Salm if ((c = fgetc(fp)) == EOF) { 41316Salm n = CHAR(msgbuf, 7); 41416Salm if (n < 0 || n > 7) { 4151057Salm des_error("decryption failed (block corrupted)"); 41616Salm return EOF; 41716Salm } 41816Salm } else 41916Salm (void)ungetc(c, fp); 42016Salm return n; 42116Salm } 42216Salm if (n > 0) 4231057Salm des_error("decryption failed (incomplete block)"); 42416Salm else if (n < 0) 4251057Salm des_error("cannot read file"); 42616Salm return EOF; 42716Salm} 42816Salm#endif /* DES */ 429