/* $NetBSD: cbc.c,v 1.27 2025/09/17 20:35:11 rillig Exp $ */ /* 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. * * 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. 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. * * from: @(#)bdes.c 5.5 (Berkeley) 6/27/91 */ /*- * 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. * 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. * * from: @(#)bdes.c 5.5 (Berkeley) 6/27/91 */ #include <sys/cdefs.h> #ifndef lint #if 0 static char *rcsid = "@(#)cbc.c,v 1.2 1994/02/01 00:34:36 alm Exp"; #else __RCSID("$NetBSD: cbc.c,v 1.27 2025/09/17 20:35:11 rillig Exp $"); #endif #endif /* not lint */ #include <sys/types.h> #include <ctype.h> #include <errno.h> #include <pwd.h> #ifdef DES #include <time.h> #endif #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)) \ des_error("des_setkey"); #define DES_XFORM(buf) \ if (des_cipher(buf, buf, 0L, (inverse ? -1 : 1))) \ des_error("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) #ifdef DES /* * global variables and related macros */ static Desbuf ivec; /* initialization vector */ static Desbuf pvec; /* padding vector */ static char bits[] = { /* used to extract bits from a char */ '\200', '\100', '\040', '\020', '\010', '\004', '\002', '\001' }; static int pflag; /* 1 to preserve parity bits */ static char des_buf[8]; /* shared buffer for get_des_char/put_des_char */ static int des_ct = 0; /* count for get_des_char/put_des_char */ static int des_n = 0; /* index for put_des_char/get_des_char */ #endif #ifdef DES static void des_error(const char *); static int hex_to_binary(int, int); static void expand_des_key(char *, char *); static void set_des_key(Desbuf); static int cbc_decode(char *, FILE *); static int cbc_encode(char *, int, FILE *); #endif /* 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 */ srand((unsigned) time((time_t *) 0)); for (i = 0; i < 8; i++) CHAR(pvec, i) = (char) (rand()/RAND_DIV); #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) ? (unsigned char) des_buf[des_n++] : EOF; #else return EOF; #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) ? (unsigned char) (des_buf[des_n++] = c) : EOF; #else return EOF; #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 EOF; #endif } #ifdef DES /* * get keyword from tty or stdin */ int get_keyword(void) { 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 */ expand_des_key(BUFFER(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 */ static void des_error(const char *s /* the message */) { seterrmsg("%s", s ? s : strerror(errno)); } /* * map a hex character to an integer */ static int hex_to_binary(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 */ static void expand_des_key(char *obuf /* bit pattern */, char *inbuf /* the key itself */) { int i, j; /* counter in a for loop */ int nbuf[64]; /* used for hex/key translation */ /* * leading '0x' or '0X' == hex key */ if (inbuf[0] == '0' && (inbuf[1] == 'x' || inbuf[1] == 'X')) { inbuf = &inbuf[2]; /* * now translate it, bombing on any illegal hex digit */ for (i = 0; i < 16 && inbuf[i]; i++) if ((nbuf[i] = hex_to_binary((int) inbuf[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 (inbuf[0] == '0' && (inbuf[1] == 'b' || inbuf[1] == 'B')) { inbuf = &inbuf[2]; /* * now translate it, bombing on any illegal binary digit */ for (i = 0; i < 16 && inbuf[i]; i++) if ((nbuf[i] = hex_to_binary((int) inbuf[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, inbuf, 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. */ static void set_des_key(Desbuf 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]&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 */ static int cbc_encode(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 */ static int cbc_decode(char *msgbuf /* I/O buffer */, FILE *fp /* input file descriptor */) { Desbuf inbuf; /* 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(BUFFER(msgbuf), 8, fp)) == 8) { /* * do the transformation */ MEMCPY(BUFFER(inbuf), BUFFER(msgbuf), 8); DES_XFORM(UBUFFER(msgbuf)); for (c = 0; c < 8; c++) UCHAR(msgbuf, c) ^= UCHAR(ivec, c); MEMCPY(BUFFER(ivec), BUFFER(inbuf), 8); /* * if the last one, handle it specially */ if ((c = fgetc(fp)) == EOF) { n = CHAR(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 */
