cbc.c revision 1.17
1 /* $NetBSD: cbc.c,v 1.17 2005/02/17 16:29:26 xtraeme 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 1.17 2005/02/17 16:29:26 xtraeme 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(void) 151 { 152 #ifdef DES 153 int i; 154 155 des_ct = des_n = 0; 156 157 /* initialize the initialization vector */ 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(FILE *fp) 171 { 172 #ifdef DES 173 if (des_n >= des_ct) { 174 des_n = 0; 175 des_ct = cbc_decode(des_buf, fp); 176 } 177 return (des_ct > 0) ? des_buf[des_n++] : EOF; 178 #else 179 return EOF; 180 #endif 181 } 182 183 184 /* put_des_char: write a char to an encrypted file; return char written */ 185 int 186 put_des_char(int c, FILE *fp) 187 { 188 #ifdef DES 189 if (des_n == sizeof des_buf) { 190 des_ct = cbc_encode(des_buf, des_n, fp); 191 des_n = 0; 192 } 193 return (des_ct >= 0) ? (des_buf[des_n++] = c) : EOF; 194 #else 195 return EOF; 196 #endif 197 } 198 199 200 /* flush_des_file: flush an encrypted file's output; return status */ 201 int 202 flush_des_file(FILE *fp) 203 { 204 #ifdef DES 205 if (des_n == sizeof des_buf) { 206 des_ct = cbc_encode(des_buf, des_n, fp); 207 des_n = 0; 208 } 209 return (des_ct >= 0 && cbc_encode(des_buf, des_n, fp) >= 0) ? 0 : EOF; 210 #else 211 return EOF; 212 #endif 213 } 214 215 #ifdef DES 216 /* 217 * get keyword from tty or stdin 218 */ 219 int 220 get_keyword(void) 221 { 222 char *p; /* used to obtain the key */ 223 Desbuf msgbuf; /* I/O buffer */ 224 225 /* 226 * get the key 227 */ 228 if (*(p = getpass("Enter key: "))) { 229 230 /* 231 * copy it, nul-padded, into the key area 232 */ 233 expand_des_key(BUFFER(msgbuf), p); 234 MEMZERO(p, _PASSWORD_LEN); 235 set_des_key(msgbuf); 236 MEMZERO(msgbuf, sizeof msgbuf); 237 return 1; 238 } 239 return 0; 240 } 241 242 243 /* 244 * print a warning message and, possibly, terminate 245 */ 246 void 247 des_error(char *s /* the message */) 248 { 249 (void)sprintf(errmsg, "%s", s ? s : strerror(errno)); 250 } 251 252 /* 253 * map a hex character to an integer 254 */ 255 int 256 hex_to_binary(int c /* char to be converted */, 257 int radix /* base (2 to 16) */) 258 { 259 switch(c) { 260 case '0': return(0x0); 261 case '1': return(0x1); 262 case '2': return(radix > 2 ? 0x2 : -1); 263 case '3': return(radix > 3 ? 0x3 : -1); 264 case '4': return(radix > 4 ? 0x4 : -1); 265 case '5': return(radix > 5 ? 0x5 : -1); 266 case '6': return(radix > 6 ? 0x6 : -1); 267 case '7': return(radix > 7 ? 0x7 : -1); 268 case '8': return(radix > 8 ? 0x8 : -1); 269 case '9': return(radix > 9 ? 0x9 : -1); 270 case 'A': case 'a': return(radix > 10 ? 0xa : -1); 271 case 'B': case 'b': return(radix > 11 ? 0xb : -1); 272 case 'C': case 'c': return(radix > 12 ? 0xc : -1); 273 case 'D': case 'd': return(radix > 13 ? 0xd : -1); 274 case 'E': case 'e': return(radix > 14 ? 0xe : -1); 275 case 'F': case 'f': return(radix > 15 ? 0xf : -1); 276 } 277 /* 278 * invalid character 279 */ 280 return(-1); 281 } 282 283 /* 284 * convert the key to a bit pattern 285 */ 286 void 287 expand_des_key(char *obuf /* bit pattern */, char *inbuf /* the key itself */) 288 { 289 int i, j; /* counter in a for loop */ 290 int nbuf[64]; /* used for hex/key translation */ 291 292 /* 293 * leading '0x' or '0X' == hex key 294 */ 295 if (inbuf[0] == '0' && (inbuf[1] == 'x' || inbuf[1] == 'X')) { 296 inbuf = &inbuf[2]; 297 /* 298 * now translate it, bombing on any illegal hex digit 299 */ 300 for (i = 0; inbuf[i] && i < 16; i++) 301 if ((nbuf[i] = hex_to_binary((int) inbuf[i], 16)) == -1) 302 des_error("bad hex digit in key"); 303 while (i < 16) 304 nbuf[i++] = 0; 305 for (i = 0; i < 8; i++) 306 obuf[i] = 307 ((nbuf[2*i]&0xf)<<4) | (nbuf[2*i+1]&0xf); 308 /* preserve parity bits */ 309 pflag = 1; 310 return; 311 } 312 /* 313 * leading '0b' or '0B' == binary key 314 */ 315 if (inbuf[0] == '0' && (inbuf[1] == 'b' || inbuf[1] == 'B')) { 316 inbuf = &inbuf[2]; 317 /* 318 * now translate it, bombing on any illegal binary digit 319 */ 320 for (i = 0; inbuf[i] && i < 16; i++) 321 if ((nbuf[i] = hex_to_binary((int) inbuf[i], 2)) == -1) 322 des_error("bad binary digit in key"); 323 while (i < 64) 324 nbuf[i++] = 0; 325 for (i = 0; i < 8; i++) 326 for (j = 0; j < 8; j++) 327 obuf[i] = (obuf[i]<<1)|nbuf[8*i+j]; 328 /* preserve parity bits */ 329 pflag = 1; 330 return; 331 } 332 /* 333 * no special leader -- ASCII 334 */ 335 (void)strncpy(obuf, inbuf, 8); 336 } 337 338 /***************** 339 * DES FUNCTIONS * 340 *****************/ 341 /* 342 * This sets the DES key and (if you're using the deszip version) 343 * the direction of the transformation. This uses the Sun 344 * to map the 64-bit key onto the 56 bits that the key schedule 345 * generation routines use: the old way, which just uses the user- 346 * supplied 64 bits as is, and the new way, which resets the parity 347 * bit to be the same as the low-order bit in each character. The 348 * new way generates a greater variety of key schedules, since many 349 * systems set the parity (high) bit of each character to 0, and the 350 * DES ignores the low order bit of each character. 351 */ 352 void 353 set_des_key(Desbuf buf /* key block */) 354 { 355 int i, j; /* counter in a for loop */ 356 int par; /* parity counter */ 357 358 /* 359 * if the parity is not preserved, flip it 360 */ 361 if (!pflag) { 362 for (i = 0; i < 8; i++) { 363 par = 0; 364 for (j = 1; j < 8; j++) 365 if ((bits[j]&UCHAR(buf, i)) != 0) 366 par++; 367 if ((par&01) == 01) 368 UCHAR(buf, i) = UCHAR(buf, i)&0177; 369 else 370 UCHAR(buf, i) = (UCHAR(buf, i)&0177)|0200; 371 } 372 } 373 374 DES_KEY(UBUFFER(buf)); 375 } 376 377 378 /* 379 * This encrypts using the Cipher Block Chaining mode of DES 380 */ 381 int 382 cbc_encode(char *msgbuf, int n, FILE *fp) 383 { 384 int inverse = 0; /* 0 to encrypt, 1 to decrypt */ 385 386 /* 387 * do the transformation 388 */ 389 if (n == 8) { 390 for (n = 0; n < 8; n++) 391 CHAR(msgbuf, n) ^= CHAR(ivec, n); 392 DES_XFORM(UBUFFER(msgbuf)); 393 MEMCPY(BUFFER(ivec), BUFFER(msgbuf), 8); 394 return WRITE(BUFFER(msgbuf), 8, fp); 395 } 396 /* 397 * at EOF or last block -- in either case, the last byte contains 398 * the character representation of the number of bytes in it 399 */ 400 /* 401 MEMZERO(msgbuf + n, 8 - n); 402 */ 403 /* 404 * Pad the last block randomly 405 */ 406 (void)MEMCPY(BUFFER(msgbuf + n), BUFFER(pvec), 8 - n); 407 CHAR(msgbuf, 7) = n; 408 for (n = 0; n < 8; n++) 409 CHAR(msgbuf, n) ^= CHAR(ivec, n); 410 DES_XFORM(UBUFFER(msgbuf)); 411 return WRITE(BUFFER(msgbuf), 8, fp); 412 } 413 414 /* 415 * This decrypts using the Cipher Block Chaining mode of DES 416 */ 417 int 418 cbc_decode(char *msgbuf /* I/O buffer */, 419 FILE *fp /* input file descriptor */) 420 { 421 Desbuf inbuf; /* temp buffer for initialization vector */ 422 int n; /* number of bytes actually read */ 423 int c; /* used to test for EOF */ 424 int inverse = 1; /* 0 to encrypt, 1 to decrypt */ 425 426 if ((n = READ(BUFFER(msgbuf), 8, fp)) == 8) { 427 /* 428 * do the transformation 429 */ 430 MEMCPY(BUFFER(inbuf), BUFFER(msgbuf), 8); 431 DES_XFORM(UBUFFER(msgbuf)); 432 for (c = 0; c < 8; c++) 433 UCHAR(msgbuf, c) ^= UCHAR(ivec, c); 434 MEMCPY(BUFFER(ivec), BUFFER(inbuf), 8); 435 /* 436 * if the last one, handle it specially 437 */ 438 if ((c = fgetc(fp)) == EOF) { 439 n = CHAR(msgbuf, 7); 440 if (n < 0 || n > 7) { 441 des_error("decryption failed (block corrupted)"); 442 return EOF; 443 } 444 } else 445 (void)ungetc(c, fp); 446 return n; 447 } 448 if (n > 0) 449 des_error("decryption failed (incomplete block)"); 450 else if (n < 0) 451 des_error("cannot read file"); 452 return EOF; 453 } 454 #endif /* DES */ 455
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