cbc.c revision 27963
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 3816Salm */ 3916Salm 4016Salm#ifndef lint 4127963Ssteve#if 0 4220420Sstevestatic char * const rcsid = "@(#)cbc.c,v 1.2 1994/02/01 00:34:36 alm Exp"; 4327963Ssteve#else 4427963Sstevestatic char * const rcsid = 4527963Ssteve "$Id: cbc.c,v 1.9 1997/02/22 14:03:12 peter Exp $"; 4627963Ssteve#endif 4716Salm#endif /* not lint */ 4816Salm 491057Salm#include <sys/types.h> 5016Salm#include <errno.h> 5116Salm#include <pwd.h> 5227963Ssteve#ifdef DES 5327963Ssteve#include <time.h> 5427963Ssteve#endif 5516Salm 5616Salm#include "ed.h" 5716Salm 581057Salm 5916Salm/* 6016Salm * Define a divisor for rand() that yields a uniform distribution in the 6116Salm * range 0-255. 6216Salm */ 6316Salm#define RAND_DIV (((unsigned) RAND_MAX + 1) >> 8) 6416Salm 6516Salm/* 6616Salm * BSD and System V systems offer special library calls that do 671057Salm * block move_liness and fills, so if possible we take advantage of them 6816Salm */ 6916Salm#define MEMCPY(dest,src,len) memcpy((dest),(src),(len)) 7016Salm#define MEMZERO(dest,len) memset((dest), 0, (len)) 7116Salm 7216Salm/* Hide the calls to the primitive encryption routines. */ 7316Salm#define DES_KEY(buf) \ 7416Salm if (des_setkey(buf)) \ 751057Salm des_error("des_setkey"); 7616Salm#define DES_XFORM(buf) \ 7716Salm if (des_cipher(buf, buf, 0L, (inverse ? -1 : 1))) \ 781057Salm des_error("des_cipher"); 7916Salm 8016Salm/* 8116Salm * read/write - no error checking 8216Salm */ 8316Salm#define READ(buf, n, fp) fread(buf, sizeof(char), n, fp) 8416Salm#define WRITE(buf, n, fp) fwrite(buf, sizeof(char), n, fp) 8516Salm 8616Salm/* 8716Salm * some things to make references easier 8816Salm */ 8916Salmtypedef char Desbuf[8]; 9016Salm#define CHAR(x,i) (x[i]) 9116Salm#define UCHAR(x,i) (x[i]) 9216Salm#define BUFFER(x) (x) 9316Salm#define UBUFFER(x) (x) 9416Salm 9516Salm/* 9616Salm * global variables and related macros 9716Salm */ 9816Salm 9916Salmenum { /* encrypt, decrypt, authenticate */ 10016Salm MODE_ENCRYPT, MODE_DECRYPT, MODE_AUTHENTICATE 10116Salm} mode = MODE_ENCRYPT; 10216Salm 10316SalmDesbuf ivec; /* initialization vector */ 10416SalmDesbuf pvec; /* padding vector */ 10516Salmchar bits[] = { /* used to extract bits from a char */ 10616Salm '\200', '\100', '\040', '\020', '\010', '\004', '\002', '\001' 10716Salm}; 10816Salmint pflag; /* 1 to preserve parity bits */ 10916Salm 1101057Salmunsigned char des_buf[8]; /* shared buffer for get_des_char/put_des_char */ 1111057Salmint des_ct = 0; /* count for get_des_char/put_des_char */ 1121057Salmint des_n = 0; /* index for put_des_char/get_des_char */ 11316Salm 11416Salm 1151057Salm/* init_des_cipher: initialize DES */ 11616Salmvoid 1171057Salminit_des_cipher() 11816Salm{ 11916Salm#ifdef DES 12016Salm int i; 12116Salm 12216Salm des_ct = des_n = 0; 12316Salm 1247165Sjoerg /* initialize the initialization vector */ 12516Salm MEMZERO(ivec, 8); 12616Salm 12716Salm /* intialize the padding vector */ 12816Salm srand((unsigned) time((time_t *) 0)); 12916Salm for (i = 0; i < 8; i++) 13016Salm CHAR(pvec, i) = (char) (rand()/RAND_DIV); 13116Salm#endif 13216Salm} 13316Salm 13416Salm 1351057Salm/* get_des_char: return next char in an encrypted file */ 1361057Salmint 1371057Salmget_des_char(fp) 13816Salm FILE *fp; 13916Salm{ 14016Salm#ifdef DES 14116Salm if (des_n >= des_ct) { 14216Salm des_n = 0; 1431057Salm des_ct = cbc_decode(des_buf, fp); 14416Salm } 14516Salm return (des_ct > 0) ? des_buf[des_n++] : EOF; 1467165Sjoerg#else 1477165Sjoerg return (getc(fp)); 14816Salm#endif 14916Salm} 15016Salm 15116Salm 1521057Salm/* put_des_char: write a char to an encrypted file; return char written */ 1531057Salmint 1541057Salmput_des_char(c, fp) 15516Salm int c; 15616Salm FILE *fp; 15716Salm{ 15816Salm#ifdef DES 15916Salm if (des_n == sizeof des_buf) { 1601057Salm des_ct = cbc_encode(des_buf, des_n, fp); 16116Salm des_n = 0; 16216Salm } 16316Salm return (des_ct >= 0) ? (des_buf[des_n++] = c) : EOF; 1647165Sjoerg#else 1657165Sjoerg return (fputc(c, fp)); 16616Salm#endif 16716Salm} 16816Salm 16916Salm 1701057Salm/* flush_des_file: flush an encrypted file's output; return status */ 1711057Salmint 1721057Salmflush_des_file(fp) 17316Salm FILE *fp; 17416Salm{ 17516Salm#ifdef DES 17616Salm if (des_n == sizeof des_buf) { 1771057Salm des_ct = cbc_encode(des_buf, des_n, fp); 17816Salm des_n = 0; 17916Salm } 1801057Salm return (des_ct >= 0 && cbc_encode(des_buf, des_n, fp) >= 0) ? 0 : EOF; 1817165Sjoerg#else 1827165Sjoerg return (fflush(fp)); 18316Salm#endif 18416Salm} 18516Salm 18616Salm#ifdef DES 18716Salm/* 18816Salm * get keyword from tty or stdin 18916Salm */ 1901057Salmint 1911057Salmget_keyword() 19216Salm{ 19316Salm register char *p; /* used to obtain the key */ 19416Salm Desbuf msgbuf; /* I/O buffer */ 19516Salm 19616Salm /* 19716Salm * get the key 19816Salm */ 19916Salm if (*(p = getpass("Enter key: "))) { 20016Salm 20116Salm /* 20216Salm * copy it, nul-padded, into the key area 20316Salm */ 2041057Salm expand_des_key(BUFFER(msgbuf), p); 20516Salm MEMZERO(p, _PASSWORD_LEN); 2061057Salm set_des_key(msgbuf); 20716Salm MEMZERO(msgbuf, sizeof msgbuf); 20816Salm return 1; 20916Salm } 21016Salm return 0; 21116Salm} 21216Salm 21316Salm 21416Salm/* 21516Salm * print a warning message and, possibly, terminate 21616Salm */ 21716Salmvoid 2181057Salmdes_error(s) 21916Salm char *s; /* the message */ 22016Salm{ 22116Salm (void)sprintf(errmsg, "%s", s ? s : strerror(errno)); 22216Salm} 22316Salm 22416Salm/* 22516Salm * map a hex character to an integer 22616Salm */ 2271057Salmint 2281057Salmhex_to_binary(c, radix) 22916Salm int c; /* char to be converted */ 23016Salm int radix; /* base (2 to 16) */ 23116Salm{ 23216Salm switch(c) { 23316Salm case '0': return(0x0); 23416Salm case '1': return(0x1); 23516Salm case '2': return(radix > 2 ? 0x2 : -1); 23616Salm case '3': return(radix > 3 ? 0x3 : -1); 23716Salm case '4': return(radix > 4 ? 0x4 : -1); 23816Salm case '5': return(radix > 5 ? 0x5 : -1); 23916Salm case '6': return(radix > 6 ? 0x6 : -1); 24016Salm case '7': return(radix > 7 ? 0x7 : -1); 24116Salm case '8': return(radix > 8 ? 0x8 : -1); 24216Salm case '9': return(radix > 9 ? 0x9 : -1); 24316Salm case 'A': case 'a': return(radix > 10 ? 0xa : -1); 24416Salm case 'B': case 'b': return(radix > 11 ? 0xb : -1); 24516Salm case 'C': case 'c': return(radix > 12 ? 0xc : -1); 24616Salm case 'D': case 'd': return(radix > 13 ? 0xd : -1); 24716Salm case 'E': case 'e': return(radix > 14 ? 0xe : -1); 24816Salm case 'F': case 'f': return(radix > 15 ? 0xf : -1); 24916Salm } 25016Salm /* 25116Salm * invalid character 25216Salm */ 25316Salm return(-1); 25416Salm} 25516Salm 25616Salm/* 25716Salm * convert the key to a bit pattern 25816Salm */ 25916Salmvoid 2601057Salmexpand_des_key(obuf, ibuf) 26116Salm char *obuf; /* bit pattern */ 26216Salm char *ibuf; /* the key itself */ 26316Salm{ 26416Salm register int i, j; /* counter in a for loop */ 26516Salm int nbuf[64]; /* used for hex/key translation */ 26616Salm 26716Salm /* 26816Salm * leading '0x' or '0X' == hex key 26916Salm */ 27016Salm if (ibuf[0] == '0' && (ibuf[1] == 'x' || ibuf[1] == 'X')) { 27116Salm ibuf = &ibuf[2]; 27216Salm /* 27316Salm * now translate it, bombing on any illegal hex digit 27416Salm */ 27516Salm for (i = 0; ibuf[i] && i < 16; i++) 2761057Salm if ((nbuf[i] = hex_to_binary((int) ibuf[i], 16)) == -1) 2771057Salm des_error("bad hex digit in key"); 27816Salm while (i < 16) 27916Salm nbuf[i++] = 0; 28016Salm for (i = 0; i < 8; i++) 28116Salm obuf[i] = 28216Salm ((nbuf[2*i]&0xf)<<4) | (nbuf[2*i+1]&0xf); 28316Salm /* preserve parity bits */ 28416Salm pflag = 1; 28516Salm return; 28616Salm } 28716Salm /* 28816Salm * leading '0b' or '0B' == binary key 28916Salm */ 29016Salm if (ibuf[0] == '0' && (ibuf[1] == 'b' || ibuf[1] == 'B')) { 29116Salm ibuf = &ibuf[2]; 29216Salm /* 29316Salm * now translate it, bombing on any illegal binary digit 29416Salm */ 29516Salm for (i = 0; ibuf[i] && i < 16; i++) 2961057Salm if ((nbuf[i] = hex_to_binary((int) ibuf[i], 2)) == -1) 2971057Salm des_error("bad binary digit in key"); 29816Salm while (i < 64) 29916Salm nbuf[i++] = 0; 30016Salm for (i = 0; i < 8; i++) 30116Salm for (j = 0; j < 8; j++) 30216Salm obuf[i] = (obuf[i]<<1)|nbuf[8*i+j]; 30316Salm /* preserve parity bits */ 30416Salm pflag = 1; 30516Salm return; 30616Salm } 30716Salm /* 30816Salm * no special leader -- ASCII 30916Salm */ 31016Salm (void)strncpy(obuf, ibuf, 8); 31116Salm} 31216Salm 31316Salm/***************** 31416Salm * DES FUNCTIONS * 31516Salm *****************/ 31616Salm/* 31716Salm * This sets the DES key and (if you're using the deszip version) 31816Salm * the direction of the transformation. This uses the Sun 31916Salm * to map the 64-bit key onto the 56 bits that the key schedule 32016Salm * generation routines use: the old way, which just uses the user- 32116Salm * supplied 64 bits as is, and the new way, which resets the parity 32216Salm * bit to be the same as the low-order bit in each character. The 32316Salm * new way generates a greater variety of key schedules, since many 32416Salm * systems set the parity (high) bit of each character to 0, and the 32516Salm * DES ignores the low order bit of each character. 32616Salm */ 32716Salmvoid 3281057Salmset_des_key(buf) 32916Salm Desbuf buf; /* key block */ 33016Salm{ 33116Salm register int i, j; /* counter in a for loop */ 33216Salm register int par; /* parity counter */ 33316Salm 33416Salm /* 33516Salm * if the parity is not preserved, flip it 33616Salm */ 33716Salm if (!pflag) { 33816Salm for (i = 0; i < 8; i++) { 33916Salm par = 0; 34016Salm for (j = 1; j < 8; j++) 34116Salm if ((bits[j]&UCHAR(buf, i)) != 0) 34216Salm par++; 34316Salm if ((par&01) == 01) 34416Salm UCHAR(buf, i) = UCHAR(buf, i)&0177; 34516Salm else 34616Salm UCHAR(buf, i) = (UCHAR(buf, i)&0177)|0200; 34716Salm } 34816Salm } 34916Salm 35016Salm DES_KEY(UBUFFER(buf)); 35116Salm} 35216Salm 35316Salm 35416Salm/* 35516Salm * This encrypts using the Cipher Block Chaining mode of DES 35616Salm */ 3571057Salmint 3581057Salmcbc_encode(msgbuf, n, fp) 35916Salm char *msgbuf; 36016Salm int n; 36116Salm FILE *fp; 36216Salm{ 36316Salm int inverse = 0; /* 0 to encrypt, 1 to decrypt */ 36416Salm 36516Salm /* 36616Salm * do the transformation 36716Salm */ 36816Salm if (n == 8) { 36916Salm for (n = 0; n < 8; n++) 37016Salm CHAR(msgbuf, n) ^= CHAR(ivec, n); 37116Salm DES_XFORM(UBUFFER(msgbuf)); 37216Salm MEMCPY(BUFFER(ivec), BUFFER(msgbuf), 8); 37316Salm return WRITE(BUFFER(msgbuf), 8, fp); 37416Salm } 37516Salm /* 37616Salm * at EOF or last block -- in either case, the last byte contains 37716Salm * the character representation of the number of bytes in it 37816Salm */ 37916Salm/* 38016Salm MEMZERO(msgbuf + n, 8 - n); 38116Salm*/ 38216Salm /* 38316Salm * Pad the last block randomly 38416Salm */ 38516Salm (void)MEMCPY(BUFFER(msgbuf + n), BUFFER(pvec), 8 - n); 38616Salm CHAR(msgbuf, 7) = n; 38716Salm for (n = 0; n < 8; n++) 38816Salm CHAR(msgbuf, n) ^= CHAR(ivec, n); 38916Salm DES_XFORM(UBUFFER(msgbuf)); 39016Salm return WRITE(BUFFER(msgbuf), 8, fp); 39116Salm} 39216Salm 39316Salm/* 39416Salm * This decrypts using the Cipher Block Chaining mode of DES 39516Salm */ 3961057Salmint 3971057Salmcbc_decode(msgbuf, fp) 39816Salm char *msgbuf; /* I/O buffer */ 39916Salm FILE *fp; /* input file descriptor */ 40016Salm{ 40116Salm Desbuf ibuf; /* temp buffer for initialization vector */ 40216Salm register int n; /* number of bytes actually read */ 40316Salm register int c; /* used to test for EOF */ 40416Salm int inverse = 1; /* 0 to encrypt, 1 to decrypt */ 40516Salm 40616Salm if ((n = READ(BUFFER(msgbuf), 8, fp)) == 8) { 40716Salm /* 40816Salm * do the transformation 40916Salm */ 41016Salm MEMCPY(BUFFER(ibuf), BUFFER(msgbuf), 8); 41116Salm DES_XFORM(UBUFFER(msgbuf)); 41216Salm for (c = 0; c < 8; c++) 41316Salm UCHAR(msgbuf, c) ^= UCHAR(ivec, c); 41416Salm MEMCPY(BUFFER(ivec), BUFFER(ibuf), 8); 41516Salm /* 41616Salm * if the last one, handle it specially 41716Salm */ 41816Salm if ((c = fgetc(fp)) == EOF) { 41916Salm n = CHAR(msgbuf, 7); 42016Salm if (n < 0 || n > 7) { 4211057Salm des_error("decryption failed (block corrupted)"); 42216Salm return EOF; 42316Salm } 42416Salm } else 42516Salm (void)ungetc(c, fp); 42616Salm return n; 42716Salm } 42816Salm if (n > 0) 4291057Salm des_error("decryption failed (incomplete block)"); 43016Salm else if (n < 0) 4311057Salm des_error("cannot read file"); 43216Salm return EOF; 43316Salm} 43416Salm#endif /* DES */ 435