1/* cbc.c: This file contains the encryption routines for the ed line editor */ 2/*- 3 * Copyright (c) 1993 The Regents of the University of California. 4 * All rights reserved. 5 * 6 * Copyright (c) 1993 Andrew Moore, Talke Studio. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#include <sys/cdefs.h> 35__FBSDID("$FreeBSD$"); 36 37#include <sys/types.h> 38#include <errno.h> 39#include <pwd.h> 40#ifdef DES 41#include <time.h> 42#include <openssl/des.h> 43#define ED_DES_INCLUDES 44#endif 45 46#include "ed.h" 47 48 49/* 50 * BSD and System V systems offer special library calls that do 51 * block move_liness and fills, so if possible we take advantage of them 52 */ 53#define MEMCPY(dest,src,len) memcpy((dest),(src),(len)) 54#define MEMZERO(dest,len) memset((dest), 0, (len)) 55 56/* Hide the calls to the primitive encryption routines. */ 57#define DES_XFORM(buf) \ 58 DES_ecb_encrypt(buf, buf, &schedule, \ 59 inverse ? DES_DECRYPT : DES_ENCRYPT); 60 61/* 62 * read/write - no error checking 63 */ 64#define READ(buf, n, fp) fread(buf, sizeof(char), n, fp) 65#define WRITE(buf, n, fp) fwrite(buf, sizeof(char), n, fp) 66 67/* 68 * global variables and related macros 69 */ 70 71#ifdef DES 72static DES_cblock ivec; /* initialization vector */ 73static DES_cblock pvec; /* padding vector */ 74 75static char bits[] = { /* used to extract bits from a char */ 76 '\200', '\100', '\040', '\020', '\010', '\004', '\002', '\001' 77}; 78 79static int pflag; /* 1 to preserve parity bits */ 80 81static DES_key_schedule schedule; /* expanded DES key */ 82 83static unsigned char des_buf[8];/* shared buffer for get_des_char/put_des_char */ 84static int des_ct = 0; /* count for get_des_char/put_des_char */ 85static int des_n = 0; /* index for put_des_char/get_des_char */ 86#endif 87 88/* init_des_cipher: initialize DES */ 89void 90init_des_cipher(void) 91{ 92#ifdef DES 93 des_ct = des_n = 0; 94 95 /* initialize the initialization vector */ 96 MEMZERO(ivec, 8); 97 98 /* initialize the padding vector */ 99 arc4random_buf(pvec, sizeof(pvec)); 100#endif 101} 102 103 104/* get_des_char: return next char in an encrypted file */ 105int 106get_des_char(FILE *fp) 107{ 108#ifdef DES 109 if (des_n >= des_ct) { 110 des_n = 0; 111 des_ct = cbc_decode(des_buf, fp); 112 } 113 return (des_ct > 0) ? des_buf[des_n++] : EOF; 114#else 115 return (getc(fp)); 116#endif 117} 118 119 120/* put_des_char: write a char to an encrypted file; return char written */ 121int 122put_des_char(int c, FILE *fp) 123{ 124#ifdef DES 125 if (des_n == sizeof des_buf) { 126 des_ct = cbc_encode(des_buf, des_n, fp); 127 des_n = 0; 128 } 129 return (des_ct >= 0) ? (des_buf[des_n++] = c) : EOF; 130#else 131 return (fputc(c, fp)); 132#endif 133} 134 135 136/* flush_des_file: flush an encrypted file's output; return status */ 137int 138flush_des_file(FILE *fp) 139{ 140#ifdef DES 141 if (des_n == sizeof des_buf) { 142 des_ct = cbc_encode(des_buf, des_n, fp); 143 des_n = 0; 144 } 145 return (des_ct >= 0 && cbc_encode(des_buf, des_n, fp) >= 0) ? 0 : EOF; 146#else 147 return (fflush(fp)); 148#endif 149} 150 151#ifdef DES 152/* 153 * get keyword from tty or stdin 154 */ 155int 156get_keyword(void) 157{ 158 char *p; /* used to obtain the key */ 159 DES_cblock msgbuf; /* I/O buffer */ 160 161 /* 162 * get the key 163 */ 164 if ((p = getpass("Enter key: ")) != NULL && *p != '\0') { 165 166 /* 167 * copy it, nul-padded, into the key area 168 */ 169 expand_des_key(msgbuf, p); 170 MEMZERO(p, _PASSWORD_LEN); 171 set_des_key(&msgbuf); 172 MEMZERO(msgbuf, sizeof msgbuf); 173 return 1; 174 } 175 return 0; 176} 177 178 179/* 180 * print a warning message and, possibly, terminate 181 */ 182void 183des_error(const char *s) 184{ 185 errmsg = s ? s : strerror(errno); 186} 187 188/* 189 * map a hex character to an integer 190 */ 191int 192hex_to_binary(int c, int radix) 193{ 194 switch(c) { 195 case '0': return(0x0); 196 case '1': return(0x1); 197 case '2': return(radix > 2 ? 0x2 : -1); 198 case '3': return(radix > 3 ? 0x3 : -1); 199 case '4': return(radix > 4 ? 0x4 : -1); 200 case '5': return(radix > 5 ? 0x5 : -1); 201 case '6': return(radix > 6 ? 0x6 : -1); 202 case '7': return(radix > 7 ? 0x7 : -1); 203 case '8': return(radix > 8 ? 0x8 : -1); 204 case '9': return(radix > 9 ? 0x9 : -1); 205 case 'A': case 'a': return(radix > 10 ? 0xa : -1); 206 case 'B': case 'b': return(radix > 11 ? 0xb : -1); 207 case 'C': case 'c': return(radix > 12 ? 0xc : -1); 208 case 'D': case 'd': return(radix > 13 ? 0xd : -1); 209 case 'E': case 'e': return(radix > 14 ? 0xe : -1); 210 case 'F': case 'f': return(radix > 15 ? 0xf : -1); 211 } 212 /* 213 * invalid character 214 */ 215 return(-1); 216} 217 218/* 219 * convert the key to a bit pattern 220 * obuf bit pattern 221 * kbuf the key itself 222 */ 223void 224expand_des_key(char *obuf, char *kbuf) 225{ 226 int i, j; /* counter in a for loop */ 227 int nbuf[64]; /* used for hex/key translation */ 228 229 /* 230 * leading '0x' or '0X' == hex key 231 */ 232 if (kbuf[0] == '0' && (kbuf[1] == 'x' || kbuf[1] == 'X')) { 233 kbuf = &kbuf[2]; 234 /* 235 * now translate it, bombing on any illegal hex digit 236 */ 237 for (i = 0; i < 16 && kbuf[i]; i++) 238 if ((nbuf[i] = hex_to_binary((int) kbuf[i], 16)) == -1) 239 des_error("bad hex digit in key"); 240 while (i < 16) 241 nbuf[i++] = 0; 242 for (i = 0; i < 8; i++) 243 obuf[i] = 244 ((nbuf[2*i]&0xf)<<4) | (nbuf[2*i+1]&0xf); 245 /* preserve parity bits */ 246 pflag = 1; 247 return; 248 } 249 /* 250 * leading '0b' or '0B' == binary key 251 */ 252 if (kbuf[0] == '0' && (kbuf[1] == 'b' || kbuf[1] == 'B')) { 253 kbuf = &kbuf[2]; 254 /* 255 * now translate it, bombing on any illegal binary digit 256 */ 257 for (i = 0; i < 16 && kbuf[i]; i++) 258 if ((nbuf[i] = hex_to_binary((int) kbuf[i], 2)) == -1) 259 des_error("bad binary digit in key"); 260 while (i < 64) 261 nbuf[i++] = 0; 262 for (i = 0; i < 8; i++) 263 for (j = 0; j < 8; j++) 264 obuf[i] = (obuf[i]<<1)|nbuf[8*i+j]; 265 /* preserve parity bits */ 266 pflag = 1; 267 return; 268 } 269 /* 270 * no special leader -- ASCII 271 */ 272 (void)strncpy(obuf, kbuf, 8); 273} 274 275/***************** 276 * DES FUNCTIONS * 277 *****************/ 278/* 279 * This sets the DES key and (if you're using the deszip version) 280 * the direction of the transformation. This uses the Sun 281 * to map the 64-bit key onto the 56 bits that the key schedule 282 * generation routines use: the old way, which just uses the user- 283 * supplied 64 bits as is, and the new way, which resets the parity 284 * bit to be the same as the low-order bit in each character. The 285 * new way generates a greater variety of key schedules, since many 286 * systems set the parity (high) bit of each character to 0, and the 287 * DES ignores the low order bit of each character. 288 */ 289void 290set_des_key(DES_cblock *buf) /* key block */ 291{ 292 int i, j; /* counter in a for loop */ 293 int par; /* parity counter */ 294 295 /* 296 * if the parity is not preserved, flip it 297 */ 298 if (!pflag) { 299 for (i = 0; i < 8; i++) { 300 par = 0; 301 for (j = 1; j < 8; j++) 302 if ((bits[j] & (*buf)[i]) != 0) 303 par++; 304 if ((par & 0x01) == 0x01) 305 (*buf)[i] &= 0x7f; 306 else 307 (*buf)[i] = ((*buf)[i] & 0x7f) | 0x80; 308 } 309 } 310 311 DES_set_odd_parity(buf); 312 DES_set_key(buf, &schedule); 313} 314 315 316/* 317 * This encrypts using the Cipher Block Chaining mode of DES 318 */ 319int 320cbc_encode(unsigned char *msgbuf, int n, FILE *fp) 321{ 322 int inverse = 0; /* 0 to encrypt, 1 to decrypt */ 323 324 /* 325 * do the transformation 326 */ 327 if (n == 8) { 328 for (n = 0; n < 8; n++) 329 msgbuf[n] ^= ivec[n]; 330 DES_XFORM((DES_cblock *)msgbuf); 331 MEMCPY(ivec, msgbuf, 8); 332 return WRITE(msgbuf, 8, fp); 333 } 334 /* 335 * at EOF or last block -- in either case, the last byte contains 336 * the character representation of the number of bytes in it 337 */ 338/* 339 MEMZERO(msgbuf + n, 8 - n); 340*/ 341 /* 342 * Pad the last block randomly 343 */ 344 (void)MEMCPY(msgbuf + n, pvec, 8 - n); 345 msgbuf[7] = n; 346 for (n = 0; n < 8; n++) 347 msgbuf[n] ^= ivec[n]; 348 DES_XFORM((DES_cblock *)msgbuf); 349 return WRITE(msgbuf, 8, fp); 350} 351 352/* 353 * This decrypts using the Cipher Block Chaining mode of DES 354 * msgbuf I/O buffer 355 * fp input file descriptor 356 */ 357int 358cbc_decode(unsigned char *msgbuf, FILE *fp) 359{ 360 DES_cblock tbuf; /* temp buffer for initialization vector */ 361 int n; /* number of bytes actually read */ 362 int c; /* used to test for EOF */ 363 int inverse = 1; /* 0 to encrypt, 1 to decrypt */ 364 365 if ((n = READ(msgbuf, 8, fp)) == 8) { 366 /* 367 * do the transformation 368 */ 369 MEMCPY(tbuf, msgbuf, 8); 370 DES_XFORM((DES_cblock *)msgbuf); 371 for (c = 0; c < 8; c++) 372 msgbuf[c] ^= ivec[c]; 373 MEMCPY(ivec, tbuf, 8); 374 /* 375 * if the last one, handle it specially 376 */ 377 if ((c = fgetc(fp)) == EOF) { 378 n = msgbuf[7]; 379 if (n < 0 || n > 7) { 380 des_error("decryption failed (block corrupted)"); 381 return EOF; 382 } 383 } else 384 (void)ungetc(c, fp); 385 return n; 386 } 387 if (n > 0) 388 des_error("decryption failed (incomplete block)"); 389 else if (n < 0) 390 des_error("cannot read file"); 391 return EOF; 392} 393#endif /* DES */ 394