cbc.c revision 1.15
1 /* $NetBSD: cbc.c,v 1.15 2003/08/07 09:05:12 agc Exp $ */ 2 3 /* cbc.c: This file contains the encryption routines for the ed line editor */ 4 /*- 5 * Copyright (c) 1993 The Regents of the University of California. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * from: @(#)bdes.c 5.5 (Berkeley) 6/27/91 33 */ 34 35 /*- 36 * Copyright (c) 1993 Andrew Moore, Talke Studio. 37 * All rights reserved. 38 * 39 * Redistribution and use in source and binary forms, with or without 40 * modification, are permitted provided that the following conditions 41 * are met: 42 * 1. Redistributions of source code must retain the above copyright 43 * notice, this list of conditions and the following disclaimer. 44 * 2. Redistributions in binary form must reproduce the above copyright 45 * notice, this list of conditions and the following disclaimer in the 46 * documentation and/or other materials provided with the distribution. 47 * 3. All advertising materials mentioning features or use of this software 48 * must display the following acknowledgement: 49 * This product includes software developed by the University of 50 * California, Berkeley and its contributors. 51 * 4. Neither the name of the University nor the names of its contributors 52 * may be used to endorse or promote products derived from this software 53 * without specific prior written permission. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 65 * SUCH DAMAGE. 66 * 67 * from: @(#)bdes.c 5.5 (Berkeley) 6/27/91 68 */ 69 70 #include <sys/cdefs.h> 71 #ifndef lint 72 #if 0 73 static char *rcsid = "@(#)cbc.c,v 1.2 1994/02/01 00:34:36 alm Exp"; 74 #else 75 __RCSID("$NetBSD: cbc.c,v 1.15 2003/08/07 09:05:12 agc Exp $"); 76 #endif 77 #endif /* not lint */ 78 79 #include <sys/types.h> 80 #include <ctype.h> 81 #include <errno.h> 82 #include <pwd.h> 83 #ifdef DES 84 #include <time.h> 85 #endif 86 87 #include "ed.h" 88 89 90 /* 91 * Define a divisor for rand() that yields a uniform distribution in the 92 * range 0-255. 93 */ 94 #define RAND_DIV (((unsigned) RAND_MAX + 1) >> 8) 95 96 /* 97 * BSD and System V systems offer special library calls that do 98 * block move_liness and fills, so if possible we take advantage of them 99 */ 100 #define MEMCPY(dest,src,len) memcpy((dest),(src),(len)) 101 #define MEMZERO(dest,len) memset((dest), 0, (len)) 102 103 /* Hide the calls to the primitive encryption routines. */ 104 #define DES_KEY(buf) \ 105 if (des_setkey(buf)) \ 106 des_error("des_setkey"); 107 #define DES_XFORM(buf) \ 108 if (des_cipher(buf, buf, 0L, (inverse ? -1 : 1))) \ 109 des_error("des_cipher"); 110 111 /* 112 * read/write - no error checking 113 */ 114 #define READ(buf, n, fp) fread(buf, sizeof(char), n, fp) 115 #define WRITE(buf, n, fp) fwrite(buf, sizeof(char), n, fp) 116 117 /* 118 * some things to make references easier 119 */ 120 typedef char Desbuf[8]; 121 #define CHAR(x,i) (x[i]) 122 #define UCHAR(x,i) (x[i]) 123 #define BUFFER(x) (x) 124 #define UBUFFER(x) (x) 125 126 #ifdef DES 127 /* 128 * global variables and related macros 129 */ 130 131 enum { /* encrypt, decrypt, authenticate */ 132 MODE_ENCRYPT, MODE_DECRYPT, MODE_AUTHENTICATE 133 } mode = MODE_ENCRYPT; 134 135 Desbuf ivec; /* initialization vector */ 136 Desbuf pvec; /* padding vector */ 137 char bits[] = { /* used to extract bits from a char */ 138 '\200', '\100', '\040', '\020', '\010', '\004', '\002', '\001' 139 }; 140 int pflag; /* 1 to preserve parity bits */ 141 142 unsigned char des_buf[8]; /* shared buffer for get_des_char/put_des_char */ 143 int des_ct = 0; /* count for get_des_char/put_des_char */ 144 int des_n = 0; /* index for put_des_char/get_des_char */ 145 #endif 146 147 148 /* init_des_cipher: initialize DES */ 149 void 150 init_des_cipher() 151 { 152 #ifdef DES 153 int i; 154 155 des_ct = des_n = 0; 156 157 /* initialize the initialization vctor */ 158 MEMZERO(ivec, 8); 159 160 /* intialize the padding vector */ 161 srand((unsigned) time((time_t *) 0)); 162 for (i = 0; i < 8; i++) 163 CHAR(pvec, i) = (char) (rand()/RAND_DIV); 164 #endif 165 } 166 167 168 /* get_des_char: return next char in an encrypted file */ 169 int 170 get_des_char(fp) 171 FILE *fp; 172 { 173 #ifdef DES 174 if (des_n >= des_ct) { 175 des_n = 0; 176 des_ct = cbc_decode(des_buf, fp); 177 } 178 return (des_ct > 0) ? des_buf[des_n++] : EOF; 179 #else 180 return EOF; 181 #endif 182 } 183 184 185 /* put_des_char: write a char to an encrypted file; return char written */ 186 int 187 put_des_char(c, fp) 188 int c; 189 FILE *fp; 190 { 191 #ifdef DES 192 if (des_n == sizeof des_buf) { 193 des_ct = cbc_encode(des_buf, des_n, fp); 194 des_n = 0; 195 } 196 return (des_ct >= 0) ? (des_buf[des_n++] = c) : EOF; 197 #else 198 return EOF; 199 #endif 200 } 201 202 203 /* flush_des_file: flush an encrypted file's output; return status */ 204 int 205 flush_des_file(fp) 206 FILE *fp; 207 { 208 #ifdef DES 209 if (des_n == sizeof des_buf) { 210 des_ct = cbc_encode(des_buf, des_n, fp); 211 des_n = 0; 212 } 213 return (des_ct >= 0 && cbc_encode(des_buf, des_n, fp) >= 0) ? 0 : EOF; 214 #else 215 return EOF; 216 #endif 217 } 218 219 #ifdef DES 220 /* 221 * get keyword from tty or stdin 222 */ 223 int 224 get_keyword() 225 { 226 char *p; /* used to obtain the key */ 227 Desbuf msgbuf; /* I/O buffer */ 228 229 /* 230 * get the key 231 */ 232 if (*(p = getpass("Enter key: "))) { 233 234 /* 235 * copy it, nul-padded, into the key area 236 */ 237 expand_des_key(BUFFER(msgbuf), p); 238 MEMZERO(p, _PASSWORD_LEN); 239 set_des_key(msgbuf); 240 MEMZERO(msgbuf, sizeof msgbuf); 241 return 1; 242 } 243 return 0; 244 } 245 246 247 /* 248 * print a warning message and, possibly, terminate 249 */ 250 void 251 des_error(s) 252 char *s; /* the message */ 253 { 254 (void)sprintf(errmsg, "%s", s ? s : strerror(errno)); 255 } 256 257 /* 258 * map a hex character to an integer 259 */ 260 int 261 hex_to_binary(c, radix) 262 int c; /* char to be converted */ 263 int radix; /* base (2 to 16) */ 264 { 265 switch(c) { 266 case '0': return(0x0); 267 case '1': return(0x1); 268 case '2': return(radix > 2 ? 0x2 : -1); 269 case '3': return(radix > 3 ? 0x3 : -1); 270 case '4': return(radix > 4 ? 0x4 : -1); 271 case '5': return(radix > 5 ? 0x5 : -1); 272 case '6': return(radix > 6 ? 0x6 : -1); 273 case '7': return(radix > 7 ? 0x7 : -1); 274 case '8': return(radix > 8 ? 0x8 : -1); 275 case '9': return(radix > 9 ? 0x9 : -1); 276 case 'A': case 'a': return(radix > 10 ? 0xa : -1); 277 case 'B': case 'b': return(radix > 11 ? 0xb : -1); 278 case 'C': case 'c': return(radix > 12 ? 0xc : -1); 279 case 'D': case 'd': return(radix > 13 ? 0xd : -1); 280 case 'E': case 'e': return(radix > 14 ? 0xe : -1); 281 case 'F': case 'f': return(radix > 15 ? 0xf : -1); 282 } 283 /* 284 * invalid character 285 */ 286 return(-1); 287 } 288 289 /* 290 * convert the key to a bit pattern 291 */ 292 void 293 expand_des_key(obuf, inbuf) 294 char *obuf; /* bit pattern */ 295 char *inbuf; /* the key itself */ 296 { 297 int i, j; /* counter in a for loop */ 298 int nbuf[64]; /* used for hex/key translation */ 299 300 /* 301 * leading '0x' or '0X' == hex key 302 */ 303 if (inbuf[0] == '0' && (inbuf[1] == 'x' || inbuf[1] == 'X')) { 304 inbuf = &inbuf[2]; 305 /* 306 * now translate it, bombing on any illegal hex digit 307 */ 308 for (i = 0; inbuf[i] && i < 16; i++) 309 if ((nbuf[i] = hex_to_binary((int) inbuf[i], 16)) == -1) 310 des_error("bad hex digit in key"); 311 while (i < 16) 312 nbuf[i++] = 0; 313 for (i = 0; i < 8; i++) 314 obuf[i] = 315 ((nbuf[2*i]&0xf)<<4) | (nbuf[2*i+1]&0xf); 316 /* preserve parity bits */ 317 pflag = 1; 318 return; 319 } 320 /* 321 * leading '0b' or '0B' == binary key 322 */ 323 if (inbuf[0] == '0' && (inbuf[1] == 'b' || inbuf[1] == 'B')) { 324 inbuf = &inbuf[2]; 325 /* 326 * now translate it, bombing on any illegal binary digit 327 */ 328 for (i = 0; inbuf[i] && i < 16; i++) 329 if ((nbuf[i] = hex_to_binary((int) inbuf[i], 2)) == -1) 330 des_error("bad binary digit in key"); 331 while (i < 64) 332 nbuf[i++] = 0; 333 for (i = 0; i < 8; i++) 334 for (j = 0; j < 8; j++) 335 obuf[i] = (obuf[i]<<1)|nbuf[8*i+j]; 336 /* preserve parity bits */ 337 pflag = 1; 338 return; 339 } 340 /* 341 * no special leader -- ASCII 342 */ 343 (void)strncpy(obuf, inbuf, 8); 344 } 345 346 /***************** 347 * DES FUNCTIONS * 348 *****************/ 349 /* 350 * This sets the DES key and (if you're using the deszip version) 351 * the direction of the transformation. This uses the Sun 352 * to map the 64-bit key onto the 56 bits that the key schedule 353 * generation routines use: the old way, which just uses the user- 354 * supplied 64 bits as is, and the new way, which resets the parity 355 * bit to be the same as the low-order bit in each character. The 356 * new way generates a greater variety of key schedules, since many 357 * systems set the parity (high) bit of each character to 0, and the 358 * DES ignores the low order bit of each character. 359 */ 360 void 361 set_des_key(buf) 362 Desbuf buf; /* key block */ 363 { 364 int i, j; /* counter in a for loop */ 365 int par; /* parity counter */ 366 367 /* 368 * if the parity is not preserved, flip it 369 */ 370 if (!pflag) { 371 for (i = 0; i < 8; i++) { 372 par = 0; 373 for (j = 1; j < 8; j++) 374 if ((bits[j]&UCHAR(buf, i)) != 0) 375 par++; 376 if ((par&01) == 01) 377 UCHAR(buf, i) = UCHAR(buf, i)&0177; 378 else 379 UCHAR(buf, i) = (UCHAR(buf, i)&0177)|0200; 380 } 381 } 382 383 DES_KEY(UBUFFER(buf)); 384 } 385 386 387 /* 388 * This encrypts using the Cipher Block Chaining mode of DES 389 */ 390 int 391 cbc_encode(msgbuf, n, fp) 392 char *msgbuf; 393 int n; 394 FILE *fp; 395 { 396 int inverse = 0; /* 0 to encrypt, 1 to decrypt */ 397 398 /* 399 * do the transformation 400 */ 401 if (n == 8) { 402 for (n = 0; n < 8; n++) 403 CHAR(msgbuf, n) ^= CHAR(ivec, n); 404 DES_XFORM(UBUFFER(msgbuf)); 405 MEMCPY(BUFFER(ivec), BUFFER(msgbuf), 8); 406 return WRITE(BUFFER(msgbuf), 8, fp); 407 } 408 /* 409 * at EOF or last block -- in either case, the last byte contains 410 * the character representation of the number of bytes in it 411 */ 412 /* 413 MEMZERO(msgbuf + n, 8 - n); 414 */ 415 /* 416 * Pad the last block randomly 417 */ 418 (void)MEMCPY(BUFFER(msgbuf + n), BUFFER(pvec), 8 - n); 419 CHAR(msgbuf, 7) = n; 420 for (n = 0; n < 8; n++) 421 CHAR(msgbuf, n) ^= CHAR(ivec, n); 422 DES_XFORM(UBUFFER(msgbuf)); 423 return WRITE(BUFFER(msgbuf), 8, fp); 424 } 425 426 /* 427 * This decrypts using the Cipher Block Chaining mode of DES 428 */ 429 int 430 cbc_decode(msgbuf, fp) 431 char *msgbuf; /* I/O buffer */ 432 FILE *fp; /* input file descriptor */ 433 { 434 Desbuf inbuf; /* temp buffer for initialization vector */ 435 int n; /* number of bytes actually read */ 436 int c; /* used to test for EOF */ 437 int inverse = 1; /* 0 to encrypt, 1 to decrypt */ 438 439 if ((n = READ(BUFFER(msgbuf), 8, fp)) == 8) { 440 /* 441 * do the transformation 442 */ 443 MEMCPY(BUFFER(inbuf), BUFFER(msgbuf), 8); 444 DES_XFORM(UBUFFER(msgbuf)); 445 for (c = 0; c < 8; c++) 446 UCHAR(msgbuf, c) ^= UCHAR(ivec, c); 447 MEMCPY(BUFFER(ivec), BUFFER(inbuf), 8); 448 /* 449 * if the last one, handle it specially 450 */ 451 if ((c = fgetc(fp)) == EOF) { 452 n = CHAR(msgbuf, 7); 453 if (n < 0 || n > 7) { 454 des_error("decryption failed (block corrupted)"); 455 return EOF; 456 } 457 } else 458 (void)ungetc(c, fp); 459 return n; 460 } 461 if (n > 0) 462 des_error("decryption failed (incomplete block)"); 463 else if (n < 0) 464 des_error("cannot read file"); 465 return EOF; 466 } 467 #endif /* DES */ 468
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