cbc.c revision 1.20
1 /* $NetBSD: cbc.c,v 1.20 2009/07/26 02:06:37 dholland 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 1.20 2009/07/26 02:06:37 dholland 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 static Desbuf ivec; /* initialization vector */ 136 static Desbuf pvec; /* padding vector */ 137 static char bits[] = { /* used to extract bits from a char */ 138 '\200', '\100', '\040', '\020', '\010', '\004', '\002', '\001' 139 }; 140 static int pflag; /* 1 to preserve parity bits */ 141 142 static char des_buf[8]; /* shared buffer for get_des_char/put_des_char */ 143 static int des_ct = 0; /* count for get_des_char/put_des_char */ 144 static int des_n = 0; /* index for put_des_char/get_des_char */ 145 #endif 146 147 148 static void des_error(const char *); 149 static int hex_to_binary(int, int); 150 static void expand_des_key(char *, char *); 151 static void set_des_key(char *); 152 static int cbc_decode(char *, FILE *); 153 static int cbc_encode(char *, int, FILE *); 154 155 156 /* init_des_cipher: initialize DES */ 157 void 158 init_des_cipher(void) 159 { 160 #ifdef DES 161 int i; 162 163 des_ct = des_n = 0; 164 165 /* initialize the initialization vector */ 166 MEMZERO(ivec, 8); 167 168 /* intialize the padding vector */ 169 srand((unsigned) time((time_t *) 0)); 170 for (i = 0; i < 8; i++) 171 CHAR(pvec, i) = (char) (rand()/RAND_DIV); 172 #endif 173 } 174 175 176 /* get_des_char: return next char in an encrypted file */ 177 int 178 get_des_char(FILE *fp) 179 { 180 #ifdef DES 181 if (des_n >= des_ct) { 182 des_n = 0; 183 des_ct = cbc_decode(des_buf, fp); 184 } 185 return (des_ct > 0) ? (unsigned char) des_buf[des_n++] : EOF; 186 #else 187 return EOF; 188 #endif 189 } 190 191 192 /* put_des_char: write a char to an encrypted file; return char written */ 193 int 194 put_des_char(int c, FILE *fp) 195 { 196 #ifdef DES 197 if (des_n == sizeof des_buf) { 198 des_ct = cbc_encode(des_buf, des_n, fp); 199 des_n = 0; 200 } 201 return (des_ct >= 0) ? (unsigned char) (des_buf[des_n++] = c) : EOF; 202 #else 203 return EOF; 204 #endif 205 } 206 207 208 /* flush_des_file: flush an encrypted file's output; return status */ 209 int 210 flush_des_file(FILE *fp) 211 { 212 #ifdef DES 213 if (des_n == sizeof des_buf) { 214 des_ct = cbc_encode(des_buf, des_n, fp); 215 des_n = 0; 216 } 217 return (des_ct >= 0 && cbc_encode(des_buf, des_n, fp) >= 0) ? 0 : EOF; 218 #else 219 return EOF; 220 #endif 221 } 222 223 #ifdef DES 224 /* 225 * get keyword from tty or stdin 226 */ 227 int 228 get_keyword(void) 229 { 230 char *p; /* used to obtain the key */ 231 Desbuf msgbuf; /* I/O buffer */ 232 233 /* 234 * get the key 235 */ 236 if (*(p = getpass("Enter key: "))) { 237 238 /* 239 * copy it, nul-padded, into the key area 240 */ 241 expand_des_key(BUFFER(msgbuf), p); 242 MEMZERO(p, _PASSWORD_LEN); 243 set_des_key(msgbuf); 244 MEMZERO(msgbuf, sizeof msgbuf); 245 return 1; 246 } 247 return 0; 248 } 249 250 251 /* 252 * print a warning message and, possibly, terminate 253 */ 254 static void 255 des_error(const char *s /* the message */) 256 { 257 (void)sprintf(errmsg, "%s", s ? s : strerror(errno)); 258 } 259 260 /* 261 * map a hex character to an integer 262 */ 263 static int 264 hex_to_binary(int c /* char to be converted */, 265 int radix /* base (2 to 16) */) 266 { 267 switch(c) { 268 case '0': return(0x0); 269 case '1': return(0x1); 270 case '2': return(radix > 2 ? 0x2 : -1); 271 case '3': return(radix > 3 ? 0x3 : -1); 272 case '4': return(radix > 4 ? 0x4 : -1); 273 case '5': return(radix > 5 ? 0x5 : -1); 274 case '6': return(radix > 6 ? 0x6 : -1); 275 case '7': return(radix > 7 ? 0x7 : -1); 276 case '8': return(radix > 8 ? 0x8 : -1); 277 case '9': return(radix > 9 ? 0x9 : -1); 278 case 'A': case 'a': return(radix > 10 ? 0xa : -1); 279 case 'B': case 'b': return(radix > 11 ? 0xb : -1); 280 case 'C': case 'c': return(radix > 12 ? 0xc : -1); 281 case 'D': case 'd': return(radix > 13 ? 0xd : -1); 282 case 'E': case 'e': return(radix > 14 ? 0xe : -1); 283 case 'F': case 'f': return(radix > 15 ? 0xf : -1); 284 } 285 /* 286 * invalid character 287 */ 288 return(-1); 289 } 290 291 /* 292 * convert the key to a bit pattern 293 */ 294 static void 295 expand_des_key(char *obuf /* bit pattern */, 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 static void 361 set_des_key(Desbuf buf /* key block */) 362 { 363 int i, j; /* counter in a for loop */ 364 int par; /* parity counter */ 365 366 /* 367 * if the parity is not preserved, flip it 368 */ 369 if (!pflag) { 370 for (i = 0; i < 8; i++) { 371 par = 0; 372 for (j = 1; j < 8; j++) 373 if ((bits[j]&UCHAR(buf, i)) != 0) 374 par++; 375 if ((par&01) == 01) 376 UCHAR(buf, i) = UCHAR(buf, i)&0177; 377 else 378 UCHAR(buf, i) = (UCHAR(buf, i)&0177)|0200; 379 } 380 } 381 382 DES_KEY(UBUFFER(buf)); 383 } 384 385 386 /* 387 * This encrypts using the Cipher Block Chaining mode of DES 388 */ 389 static int 390 cbc_encode(char *msgbuf, int n, FILE *fp) 391 { 392 int inverse = 0; /* 0 to encrypt, 1 to decrypt */ 393 394 /* 395 * do the transformation 396 */ 397 if (n == 8) { 398 for (n = 0; n < 8; n++) 399 CHAR(msgbuf, n) ^= CHAR(ivec, n); 400 DES_XFORM(UBUFFER(msgbuf)); 401 MEMCPY(BUFFER(ivec), BUFFER(msgbuf), 8); 402 return WRITE(BUFFER(msgbuf), 8, fp); 403 } 404 /* 405 * at EOF or last block -- in either case, the last byte contains 406 * the character representation of the number of bytes in it 407 */ 408 /* 409 MEMZERO(msgbuf + n, 8 - n); 410 */ 411 /* 412 * Pad the last block randomly 413 */ 414 (void)MEMCPY(BUFFER(msgbuf + n), BUFFER(pvec), 8 - n); 415 CHAR(msgbuf, 7) = n; 416 for (n = 0; n < 8; n++) 417 CHAR(msgbuf, n) ^= CHAR(ivec, n); 418 DES_XFORM(UBUFFER(msgbuf)); 419 return WRITE(BUFFER(msgbuf), 8, fp); 420 } 421 422 /* 423 * This decrypts using the Cipher Block Chaining mode of DES 424 */ 425 static int 426 cbc_decode(char *msgbuf /* I/O buffer */, 427 FILE *fp /* input file descriptor */) 428 { 429 Desbuf inbuf; /* temp buffer for initialization vector */ 430 int n; /* number of bytes actually read */ 431 int c; /* used to test for EOF */ 432 int inverse = 1; /* 0 to encrypt, 1 to decrypt */ 433 434 if ((n = READ(BUFFER(msgbuf), 8, fp)) == 8) { 435 /* 436 * do the transformation 437 */ 438 MEMCPY(BUFFER(inbuf), BUFFER(msgbuf), 8); 439 DES_XFORM(UBUFFER(msgbuf)); 440 for (c = 0; c < 8; c++) 441 UCHAR(msgbuf, c) ^= UCHAR(ivec, c); 442 MEMCPY(BUFFER(ivec), BUFFER(inbuf), 8); 443 /* 444 * if the last one, handle it specially 445 */ 446 if ((c = fgetc(fp)) == EOF) { 447 n = CHAR(msgbuf, 7); 448 if (n < 0 || n > 7) { 449 des_error("decryption failed (block corrupted)"); 450 return EOF; 451 } 452 } else 453 (void)ungetc(c, fp); 454 return n; 455 } 456 if (n > 0) 457 des_error("decryption failed (incomplete block)"); 458 else if (n < 0) 459 des_error("cannot read file"); 460 return EOF; 461 } 462 #endif /* DES */ 463
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