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Diffstat (limited to 'bin/ed/cbc.c')
-rw-r--r-- | bin/ed/cbc.c | 435 |
1 files changed, 435 insertions, 0 deletions
diff --git a/bin/ed/cbc.c b/bin/ed/cbc.c new file mode 100644 index 0000000..95ce63c --- /dev/null +++ b/bin/ed/cbc.c @@ -0,0 +1,435 @@ +/* cbc.c: This file contains the encryption routines for the ed line editor */ +/*- + * Copyright (c) 1991 The Regents of the University of California. + * All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Matt Bishop of Dartmouth College. + * + * The United States Government has rights in this work pursuant + * to contract no. NAG 2-680 between the National Aeronautics and + * Space Administration and Dartmouth College. + * + * 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. + */ + +#ifndef lint +static char sccsid[] = "@(#)cbc.c 5.5 (Berkeley) 6/27/91"; +#endif /* not lint */ + +/* Author: Matt Bishop + * Department of Mathematics and Computer Science + * Dartmouth College + * Hanover, NH 03755 + * Email: Matt.Bishop@dartmouth.edu + * ...!decvax!dartvax!Matt.Bishop + * + * See Technical Report PCS-TR91-158, Department of Mathematics and Computer + * Science, Dartmouth College, for a detailed description of the implemen- + * tation and differences between it and Sun's. The DES is described in + * FIPS PUB 46, and the modes in FIPS PUB 81 (see either the manual page + * or the technical report for a complete reference). + */ + +#include <errno.h> +#include <pwd.h> +#include <unistd.h> +#include <stdio.h> +#include <ctype.h> +#include <stdlib.h> +#include <string.h> +#include <sys/types.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 moves 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)) \ + err("des_setkey"); +#define DES_XFORM(buf) \ + if (des_cipher(buf, buf, 0L, (inverse ? -1 : 1))) \ + err("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 */ + +char des_buf[8]; /* shared buffer for desgetc/desputc */ +int des_ct = 0; /* count for desgetc/desputc */ +int des_n = 0; /* index for desputc/desgetc */ + + +/* desinit: initialize DES */ +void +desinit() +{ +#ifdef DES + int i; + + des_ct = des_n = 0; + + /* initialize the initialization vctor */ + 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 +} + + +/* desgetc: return next char in an encrypted file */ +desgetc(fp) + FILE *fp; +{ +#ifdef DES + if (des_n >= des_ct) { + des_n = 0; + des_ct = cbcdec(des_buf, fp); + } + return (des_ct > 0) ? des_buf[des_n++] : EOF; +#endif +} + + +/* desputc: write a char to an encrypted file; return char written */ +desputc(c, fp) + int c; + FILE *fp; +{ +#ifdef DES + if (des_n == sizeof des_buf) { + des_ct = cbcenc(des_buf, des_n, fp); + des_n = 0; + } + return (des_ct >= 0) ? (des_buf[des_n++] = c) : EOF; +#endif +} + + +/* desflush: flush an encrypted file's output; return status */ +desflush(fp) + FILE *fp; +{ +#ifdef DES + if (des_n == sizeof des_buf) { + des_ct = cbcenc(des_buf, des_n, fp); + des_n = 0; + } + return (des_ct >= 0 && cbcenc(des_buf, des_n, fp) >= 0) ? 0 : EOF; +#endif +} + +#ifdef DES +/* + * get keyword from tty or stdin + */ +getkey() +{ + 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 + */ + cvtkey(BUFFER(msgbuf), p); + MEMZERO(p, _PASSWORD_LEN); + makekey(msgbuf); + MEMZERO(msgbuf, sizeof msgbuf); + return 1; + } + return 0; +} + + +extern char errmsg[]; + +/* + * print a warning message and, possibly, terminate + */ +void +err(s) + char *s; /* the message */ +{ + (void)sprintf(errmsg, "%s", s ? s : strerror(errno)); +} + +/* + * map a hex character to an integer + */ +tobinhex(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 +cvtkey(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] = tobinhex((int) ibuf[i], 16)) == -1) + err("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] = tobinhex((int) ibuf[i], 2)) == -1) + err("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 +makekey(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 + */ +cbcenc(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 + */ +cbcdec(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) { + err("decryption failed (block corrupted)"); + return EOF; + } + } else + (void)ungetc(c, fp); + return n; + } + if (n > 0) + err("decryption failed (incomplete block)"); + else if (n < 0) + err("cannot read file"); + return EOF; +} +#endif /* DES */ |