cbc.c revision 101093
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. 3616Salm */ 3716Salm 3899109Sobrien#include <sys/cdefs.h> 3999109Sobrien__FBSDID("$FreeBSD: head/bin/ed/cbc.c 101093 2002-07-31 16:52:16Z markm $"); 4016Salm 411057Salm#include <sys/types.h> 4216Salm#include <errno.h> 4316Salm#include <pwd.h> 4427963Ssteve#ifdef DES 4527963Ssteve#include <time.h> 4627963Ssteve#endif 4716Salm 4816Salm#include "ed.h" 4916Salm 501057Salm 5116Salm/* 5216Salm * BSD and System V systems offer special library calls that do 531057Salm * block move_liness and fills, so if possible we take advantage of them 5416Salm */ 5516Salm#define MEMCPY(dest,src,len) memcpy((dest),(src),(len)) 5616Salm#define MEMZERO(dest,len) memset((dest), 0, (len)) 5716Salm 5816Salm/* Hide the calls to the primitive encryption routines. */ 59101093Smarkm#define DES_KEY(buf) \ 60101093Smarkm if (des_setkey(buf)) \ 611057Salm des_error("des_setkey"); 62101093Smarkm#define DES_XFORM(buf) \ 63101093Smarkm if (des_cipher((char *)buf, (char *)buf, 0L, inverse ? -1 : 1)) \ 641057Salm des_error("des_cipher"); 6516Salm 6616Salm/* 6716Salm * read/write - no error checking 6816Salm */ 6916Salm#define READ(buf, n, fp) fread(buf, sizeof(char), n, fp) 7016Salm#define WRITE(buf, n, fp) fwrite(buf, sizeof(char), n, fp) 7116Salm 7216Salm/* 7316Salm * some things to make references easier 7416Salm */ 7516Salmtypedef char Desbuf[8]; 7616Salm#define CHAR(x,i) (x[i]) 7716Salm#define UCHAR(x,i) (x[i]) 7816Salm#define BUFFER(x) (x) 7916Salm#define UBUFFER(x) (x) 8016Salm 8116Salm/* 8216Salm * global variables and related macros 8316Salm */ 8416Salm 8516Salmenum { /* encrypt, decrypt, authenticate */ 8616Salm MODE_ENCRYPT, MODE_DECRYPT, MODE_AUTHENTICATE 8716Salm} mode = MODE_ENCRYPT; 8816Salm 8916SalmDesbuf ivec; /* initialization vector */ 9016SalmDesbuf pvec; /* padding vector */ 9116Salmchar bits[] = { /* used to extract bits from a char */ 9216Salm '\200', '\100', '\040', '\020', '\010', '\004', '\002', '\001' 9316Salm}; 9416Salmint pflag; /* 1 to preserve parity bits */ 9516Salm 961057Salmunsigned char des_buf[8]; /* shared buffer for get_des_char/put_des_char */ 971057Salmint des_ct = 0; /* count for get_des_char/put_des_char */ 981057Salmint des_n = 0; /* index for put_des_char/get_des_char */ 9916Salm 10016Salm 1011057Salm/* init_des_cipher: initialize DES */ 10216Salmvoid 10390109Simpinit_des_cipher(void) 10416Salm{ 10516Salm#ifdef DES 10616Salm int i; 10716Salm 10816Salm des_ct = des_n = 0; 10916Salm 1107165Sjoerg /* initialize the initialization vector */ 11116Salm MEMZERO(ivec, 8); 11216Salm 11346684Skris /* initialize the padding vector */ 11416Salm for (i = 0; i < 8; i++) 11573563Skris CHAR(pvec, i) = (char) (arc4random() % 256); 11616Salm#endif 11716Salm} 11816Salm 11916Salm 1201057Salm/* get_des_char: return next char in an encrypted file */ 1211057Salmint 12290109Simpget_des_char(FILE *fp) 12316Salm{ 12416Salm#ifdef DES 12516Salm if (des_n >= des_ct) { 12616Salm des_n = 0; 1271057Salm des_ct = cbc_decode(des_buf, fp); 12816Salm } 12916Salm return (des_ct > 0) ? des_buf[des_n++] : EOF; 1307165Sjoerg#else 1317165Sjoerg return (getc(fp)); 13216Salm#endif 13316Salm} 13416Salm 13516Salm 1361057Salm/* put_des_char: write a char to an encrypted file; return char written */ 1371057Salmint 13890109Simpput_des_char(int c, FILE *fp) 13916Salm{ 14016Salm#ifdef DES 14116Salm if (des_n == sizeof des_buf) { 1421057Salm des_ct = cbc_encode(des_buf, des_n, fp); 14316Salm des_n = 0; 14416Salm } 14516Salm return (des_ct >= 0) ? (des_buf[des_n++] = c) : EOF; 1467165Sjoerg#else 1477165Sjoerg return (fputc(c, fp)); 14816Salm#endif 14916Salm} 15016Salm 15116Salm 1521057Salm/* flush_des_file: flush an encrypted file's output; return status */ 1531057Salmint 15490109Simpflush_des_file(FILE *fp) 15516Salm{ 15616Salm#ifdef DES 15716Salm if (des_n == sizeof des_buf) { 1581057Salm des_ct = cbc_encode(des_buf, des_n, fp); 15916Salm des_n = 0; 16016Salm } 1611057Salm return (des_ct >= 0 && cbc_encode(des_buf, des_n, fp) >= 0) ? 0 : EOF; 1627165Sjoerg#else 1637165Sjoerg return (fflush(fp)); 16416Salm#endif 16516Salm} 16616Salm 16716Salm#ifdef DES 16816Salm/* 16916Salm * get keyword from tty or stdin 17016Salm */ 1711057Salmint 17290109Simpget_keyword(void) 17316Salm{ 17481220Smike char *p; /* used to obtain the key */ 17516Salm Desbuf msgbuf; /* I/O buffer */ 17616Salm 17716Salm /* 17816Salm * get the key 17916Salm */ 18016Salm if (*(p = getpass("Enter key: "))) { 18116Salm 18216Salm /* 18316Salm * copy it, nul-padded, into the key area 18416Salm */ 1851057Salm expand_des_key(BUFFER(msgbuf), p); 18616Salm MEMZERO(p, _PASSWORD_LEN); 1871057Salm set_des_key(msgbuf); 18816Salm MEMZERO(msgbuf, sizeof msgbuf); 18916Salm return 1; 19016Salm } 19116Salm return 0; 19216Salm} 19316Salm 19416Salm 19516Salm/* 19616Salm * print a warning message and, possibly, terminate 19716Salm */ 19816Salmvoid 19990109Simpdes_error(const char *s) 20016Salm{ 20181220Smike errmsg = s ? s : strerror(errno); 20216Salm} 20316Salm 20416Salm/* 20516Salm * map a hex character to an integer 20616Salm */ 2071057Salmint 20890109Simphex_to_binary(int c, int radix) 20916Salm{ 21016Salm switch(c) { 21116Salm case '0': return(0x0); 21216Salm case '1': return(0x1); 21316Salm case '2': return(radix > 2 ? 0x2 : -1); 21416Salm case '3': return(radix > 3 ? 0x3 : -1); 21516Salm case '4': return(radix > 4 ? 0x4 : -1); 21616Salm case '5': return(radix > 5 ? 0x5 : -1); 21716Salm case '6': return(radix > 6 ? 0x6 : -1); 21816Salm case '7': return(radix > 7 ? 0x7 : -1); 21916Salm case '8': return(radix > 8 ? 0x8 : -1); 22016Salm case '9': return(radix > 9 ? 0x9 : -1); 22116Salm case 'A': case 'a': return(radix > 10 ? 0xa : -1); 22216Salm case 'B': case 'b': return(radix > 11 ? 0xb : -1); 22316Salm case 'C': case 'c': return(radix > 12 ? 0xc : -1); 22416Salm case 'D': case 'd': return(radix > 13 ? 0xd : -1); 22516Salm case 'E': case 'e': return(radix > 14 ? 0xe : -1); 22616Salm case 'F': case 'f': return(radix > 15 ? 0xf : -1); 22716Salm } 22816Salm /* 22916Salm * invalid character 23016Salm */ 23116Salm return(-1); 23216Salm} 23316Salm 23416Salm/* 23516Salm * convert the key to a bit pattern 23690109Simp * obuf bit pattern 23790109Simp * kbuf the key itself 23816Salm */ 23916Salmvoid 24090109Simpexpand_des_key(char *obuf, char *kbuf) 24116Salm{ 24281220Smike int i, j; /* counter in a for loop */ 24316Salm int nbuf[64]; /* used for hex/key translation */ 24416Salm 24516Salm /* 24616Salm * leading '0x' or '0X' == hex key 24716Salm */ 24881220Smike if (kbuf[0] == '0' && (kbuf[1] == 'x' || kbuf[1] == 'X')) { 24981220Smike kbuf = &kbuf[2]; 25016Salm /* 25116Salm * now translate it, bombing on any illegal hex digit 25216Salm */ 25381220Smike for (i = 0; kbuf[i] && i < 16; i++) 25481220Smike if ((nbuf[i] = hex_to_binary((int) kbuf[i], 16)) == -1) 2551057Salm des_error("bad hex digit in key"); 25616Salm while (i < 16) 25716Salm nbuf[i++] = 0; 25816Salm for (i = 0; i < 8; i++) 25916Salm obuf[i] = 26016Salm ((nbuf[2*i]&0xf)<<4) | (nbuf[2*i+1]&0xf); 26116Salm /* preserve parity bits */ 26216Salm pflag = 1; 26316Salm return; 26416Salm } 26516Salm /* 26616Salm * leading '0b' or '0B' == binary key 26716Salm */ 26881220Smike if (kbuf[0] == '0' && (kbuf[1] == 'b' || kbuf[1] == 'B')) { 26981220Smike kbuf = &kbuf[2]; 27016Salm /* 27116Salm * now translate it, bombing on any illegal binary digit 27216Salm */ 27381220Smike for (i = 0; kbuf[i] && i < 16; i++) 27481220Smike if ((nbuf[i] = hex_to_binary((int) kbuf[i], 2)) == -1) 2751057Salm des_error("bad binary digit in key"); 27616Salm while (i < 64) 27716Salm nbuf[i++] = 0; 27816Salm for (i = 0; i < 8; i++) 27916Salm for (j = 0; j < 8; j++) 28016Salm obuf[i] = (obuf[i]<<1)|nbuf[8*i+j]; 28116Salm /* preserve parity bits */ 28216Salm pflag = 1; 28316Salm return; 28416Salm } 28516Salm /* 28616Salm * no special leader -- ASCII 28716Salm */ 28881220Smike (void)strncpy(obuf, kbuf, 8); 28916Salm} 29016Salm 29116Salm/***************** 29216Salm * DES FUNCTIONS * 29316Salm *****************/ 29416Salm/* 29516Salm * This sets the DES key and (if you're using the deszip version) 29616Salm * the direction of the transformation. This uses the Sun 29716Salm * to map the 64-bit key onto the 56 bits that the key schedule 29816Salm * generation routines use: the old way, which just uses the user- 29916Salm * supplied 64 bits as is, and the new way, which resets the parity 30016Salm * bit to be the same as the low-order bit in each character. The 30116Salm * new way generates a greater variety of key schedules, since many 30216Salm * systems set the parity (high) bit of each character to 0, and the 30316Salm * DES ignores the low order bit of each character. 30416Salm */ 30516Salmvoid 30690109Simpset_des_key(Desbuf buf) /* key block */ 30716Salm{ 30881220Smike int i, j; /* counter in a for loop */ 30981220Smike int par; /* parity counter */ 31016Salm 31116Salm /* 31216Salm * if the parity is not preserved, flip it 31316Salm */ 31416Salm if (!pflag) { 31516Salm for (i = 0; i < 8; i++) { 31616Salm par = 0; 31716Salm for (j = 1; j < 8; j++) 31816Salm if ((bits[j]&UCHAR(buf, i)) != 0) 31916Salm par++; 32016Salm if ((par&01) == 01) 32116Salm UCHAR(buf, i) = UCHAR(buf, i)&0177; 32216Salm else 32316Salm UCHAR(buf, i) = (UCHAR(buf, i)&0177)|0200; 32416Salm } 32516Salm } 32616Salm 32716Salm DES_KEY(UBUFFER(buf)); 32816Salm} 32916Salm 33016Salm 33116Salm/* 33216Salm * This encrypts using the Cipher Block Chaining mode of DES 33316Salm */ 3341057Salmint 335101093Smarkmcbc_encode(unsigned char *msgbuf, int n, FILE *fp) 33616Salm{ 33716Salm int inverse = 0; /* 0 to encrypt, 1 to decrypt */ 33816Salm 33916Salm /* 34016Salm * do the transformation 34116Salm */ 34216Salm if (n == 8) { 34316Salm for (n = 0; n < 8; n++) 34416Salm CHAR(msgbuf, n) ^= CHAR(ivec, n); 34516Salm DES_XFORM(UBUFFER(msgbuf)); 34616Salm MEMCPY(BUFFER(ivec), BUFFER(msgbuf), 8); 34716Salm return WRITE(BUFFER(msgbuf), 8, fp); 34816Salm } 34916Salm /* 35016Salm * at EOF or last block -- in either case, the last byte contains 35116Salm * the character representation of the number of bytes in it 35216Salm */ 35316Salm/* 35416Salm MEMZERO(msgbuf + n, 8 - n); 35516Salm*/ 35616Salm /* 35716Salm * Pad the last block randomly 35816Salm */ 35916Salm (void)MEMCPY(BUFFER(msgbuf + n), BUFFER(pvec), 8 - n); 36016Salm CHAR(msgbuf, 7) = n; 36116Salm for (n = 0; n < 8; n++) 36216Salm CHAR(msgbuf, n) ^= CHAR(ivec, n); 36316Salm DES_XFORM(UBUFFER(msgbuf)); 36416Salm return WRITE(BUFFER(msgbuf), 8, fp); 36516Salm} 36616Salm 36716Salm/* 36816Salm * This decrypts using the Cipher Block Chaining mode of DES 36990109Simp * msgbuf I/O buffer 37090109Simp * fp input file descriptor 37116Salm */ 3721057Salmint 373101093Smarkmcbc_decode(unsigned char *msgbuf, FILE *fp) 37416Salm{ 37581220Smike Desbuf tbuf; /* temp buffer for initialization vector */ 37681220Smike int n; /* number of bytes actually read */ 37781220Smike int c; /* used to test for EOF */ 37816Salm int inverse = 1; /* 0 to encrypt, 1 to decrypt */ 37916Salm 38016Salm if ((n = READ(BUFFER(msgbuf), 8, fp)) == 8) { 38116Salm /* 38216Salm * do the transformation 38316Salm */ 38481220Smike MEMCPY(BUFFER(tbuf), BUFFER(msgbuf), 8); 38516Salm DES_XFORM(UBUFFER(msgbuf)); 38616Salm for (c = 0; c < 8; c++) 38716Salm UCHAR(msgbuf, c) ^= UCHAR(ivec, c); 38881220Smike MEMCPY(BUFFER(ivec), BUFFER(tbuf), 8); 38916Salm /* 39016Salm * if the last one, handle it specially 39116Salm */ 39216Salm if ((c = fgetc(fp)) == EOF) { 39316Salm n = CHAR(msgbuf, 7); 39416Salm if (n < 0 || n > 7) { 3951057Salm des_error("decryption failed (block corrupted)"); 39616Salm return EOF; 39716Salm } 39816Salm } else 39916Salm (void)ungetc(c, fp); 40016Salm return n; 40116Salm } 40216Salm if (n > 0) 4031057Salm des_error("decryption failed (incomplete block)"); 40416Salm else if (n < 0) 4051057Salm des_error("cannot read file"); 40616Salm return EOF; 40716Salm} 40816Salm#endif /* DES */ 409