1 /* $NetBSD: cbc.c,v 1.27 2025/09/17 20:35:11 rillig 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 1.27 2025/09/17 20:35:11 rillig 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 moves 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 static Desbuf ivec; /* initialization vector */ 132 static Desbuf pvec; /* padding vector */ 133 static char bits[] = { /* used to extract bits from a char */ 134 '\200', '\100', '\040', '\020', '\010', '\004', '\002', '\001' 135 }; 136 static int pflag; /* 1 to preserve parity bits */ 137 138 static char des_buf[8]; /* shared buffer for get_des_char/put_des_char */ 139 static int des_ct = 0; /* count for get_des_char/put_des_char */ 140 static int des_n = 0; /* index for put_des_char/get_des_char */ 141 #endif 142 143 144 #ifdef DES 145 static void des_error(const char *); 146 static int hex_to_binary(int, int); 147 static void expand_des_key(char *, char *); 148 static void set_des_key(Desbuf); 149 static int cbc_decode(char *, FILE *); 150 static int cbc_encode(char *, int, FILE *); 151 #endif 152 153 154 /* init_des_cipher: initialize DES */ 155 void 156 init_des_cipher(void) 157 { 158 #ifdef DES 159 int i; 160 161 des_ct = des_n = 0; 162 163 /* initialize the initialization vector */ 164 MEMZERO(ivec, 8); 165 166 /* initialize the padding vector */ 167 srand((unsigned) time((time_t *) 0)); 168 for (i = 0; i < 8; i++) 169 CHAR(pvec, i) = (char) (rand()/RAND_DIV); 170 #endif 171 } 172 173 174 /* get_des_char: return next char in an encrypted file */ 175 int 176 get_des_char(FILE *fp) 177 { 178 #ifdef DES 179 if (des_n >= des_ct) { 180 des_n = 0; 181 des_ct = cbc_decode(des_buf, fp); 182 } 183 return (des_ct > 0) ? (unsigned char) des_buf[des_n++] : EOF; 184 #else 185 return EOF; 186 #endif 187 } 188 189 190 /* put_des_char: write a char to an encrypted file; return char written */ 191 int 192 put_des_char(int c, FILE *fp) 193 { 194 #ifdef DES 195 if (des_n == sizeof des_buf) { 196 des_ct = cbc_encode(des_buf, des_n, fp); 197 des_n = 0; 198 } 199 return (des_ct >= 0) ? (unsigned char) (des_buf[des_n++] = c) : EOF; 200 #else 201 return EOF; 202 #endif 203 } 204 205 206 /* flush_des_file: flush an encrypted file's output; return status */ 207 int 208 flush_des_file(FILE *fp) 209 { 210 #ifdef DES 211 if (des_n == sizeof des_buf) { 212 des_ct = cbc_encode(des_buf, des_n, fp); 213 des_n = 0; 214 } 215 return (des_ct >= 0 && cbc_encode(des_buf, des_n, fp) >= 0) ? 0 : EOF; 216 #else 217 return EOF; 218 #endif 219 } 220 221 #ifdef DES 222 /* 223 * get keyword from tty or stdin 224 */ 225 int 226 get_keyword(void) 227 { 228 char *p; /* used to obtain the key */ 229 Desbuf msgbuf; /* I/O buffer */ 230 231 /* 232 * get the key 233 */ 234 if (*(p = getpass("Enter key: "))) { 235 236 /* 237 * copy it, nul-padded, into the key area 238 */ 239 expand_des_key(BUFFER(msgbuf), p); 240 MEMZERO(p, _PASSWORD_LEN); 241 set_des_key(msgbuf); 242 MEMZERO(msgbuf, sizeof msgbuf); 243 return 1; 244 } 245 return 0; 246 } 247 248 249 /* 250 * print a warning message and, possibly, terminate 251 */ 252 static void 253 des_error(const char *s /* the message */) 254 { 255 seterrmsg("%s", s ? s : strerror(errno)); 256 } 257 258 /* 259 * map a hex character to an integer 260 */ 261 static int 262 hex_to_binary(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 static void 293 expand_des_key(char *obuf /* bit pattern */, char *inbuf /* the key itself */) 294 { 295 int i, j; /* counter in a for loop */ 296 int nbuf[64]; /* used for hex/key translation */ 297 298 /* 299 * leading '0x' or '0X' == hex key 300 */ 301 if (inbuf[0] == '0' && (inbuf[1] == 'x' || inbuf[1] == 'X')) { 302 inbuf = &inbuf[2]; 303 /* 304 * now translate it, bombing on any illegal hex digit 305 */ 306 for (i = 0; i < 16 && inbuf[i]; i++) 307 if ((nbuf[i] = hex_to_binary((int) inbuf[i], 16)) == -1) 308 des_error("bad hex digit in key"); 309 while (i < 16) 310 nbuf[i++] = 0; 311 for (i = 0; i < 8; i++) 312 obuf[i] = 313 ((nbuf[2*i]&0xf)<<4) | (nbuf[2*i+1]&0xf); 314 /* preserve parity bits */ 315 pflag = 1; 316 return; 317 } 318 /* 319 * leading '0b' or '0B' == binary key 320 */ 321 if (inbuf[0] == '0' && (inbuf[1] == 'b' || inbuf[1] == 'B')) { 322 inbuf = &inbuf[2]; 323 /* 324 * now translate it, bombing on any illegal binary digit 325 */ 326 for (i = 0; i < 16 && inbuf[i]; i++) 327 if ((nbuf[i] = hex_to_binary((int) inbuf[i], 2)) == -1) 328 des_error("bad binary digit in key"); 329 while (i < 64) 330 nbuf[i++] = 0; 331 for (i = 0; i < 8; i++) 332 for (j = 0; j < 8; j++) 333 obuf[i] = (obuf[i]<<1)|nbuf[8*i+j]; 334 /* preserve parity bits */ 335 pflag = 1; 336 return; 337 } 338 /* 339 * no special leader -- ASCII 340 */ 341 (void)strncpy(obuf, inbuf, 8); 342 } 343 344 /***************** 345 * DES FUNCTIONS * 346 *****************/ 347 /* 348 * This sets the DES key and (if you're using the deszip version) 349 * the direction of the transformation. This uses the Sun 350 * to map the 64-bit key onto the 56 bits that the key schedule 351 * generation routines use: the old way, which just uses the user- 352 * supplied 64 bits as is, and the new way, which resets the parity 353 * bit to be the same as the low-order bit in each character. The 354 * new way generates a greater variety of key schedules, since many 355 * systems set the parity (high) bit of each character to 0, and the 356 * DES ignores the low order bit of each character. 357 */ 358 static void 359 set_des_key(Desbuf buf /* key block */) 360 { 361 int i, j; /* counter in a for loop */ 362 int par; /* parity counter */ 363 364 /* 365 * if the parity is not preserved, flip it 366 */ 367 if (!pflag) { 368 for (i = 0; i < 8; i++) { 369 par = 0; 370 for (j = 1; j < 8; j++) 371 if ((bits[j]&UCHAR(buf, i)) != 0) 372 par++; 373 if ((par&01) == 01) 374 UCHAR(buf, i) = UCHAR(buf, i)&0177; 375 else 376 UCHAR(buf, i) = (UCHAR(buf, i)&0177)|0200; 377 } 378 } 379 380 DES_KEY(UBUFFER(buf)); 381 } 382 383 384 /* 385 * This encrypts using the Cipher Block Chaining mode of DES 386 */ 387 static int 388 cbc_encode(char *msgbuf, int n, FILE *fp) 389 { 390 int inverse = 0; /* 0 to encrypt, 1 to decrypt */ 391 392 /* 393 * do the transformation 394 */ 395 if (n == 8) { 396 for (n = 0; n < 8; n++) 397 CHAR(msgbuf, n) ^= CHAR(ivec, n); 398 DES_XFORM(UBUFFER(msgbuf)); 399 MEMCPY(BUFFER(ivec), BUFFER(msgbuf), 8); 400 return WRITE(BUFFER(msgbuf), 8, fp); 401 } 402 /* 403 * at EOF or last block -- in either case, the last byte contains 404 * the character representation of the number of bytes in it 405 */ 406 /* 407 MEMZERO(msgbuf + n, 8 - n); 408 */ 409 /* 410 * Pad the last block randomly 411 */ 412 (void)MEMCPY(BUFFER(msgbuf + n), BUFFER(pvec), 8 - n); 413 CHAR(msgbuf, 7) = n; 414 for (n = 0; n < 8; n++) 415 CHAR(msgbuf, n) ^= CHAR(ivec, n); 416 DES_XFORM(UBUFFER(msgbuf)); 417 return WRITE(BUFFER(msgbuf), 8, fp); 418 } 419 420 /* 421 * This decrypts using the Cipher Block Chaining mode of DES 422 */ 423 static int 424 cbc_decode(char *msgbuf /* I/O buffer */, 425 FILE *fp /* input file descriptor */) 426 { 427 Desbuf inbuf; /* temp buffer for initialization vector */ 428 int n; /* number of bytes actually read */ 429 int c; /* used to test for EOF */ 430 int inverse = 1; /* 0 to encrypt, 1 to decrypt */ 431 432 if ((n = READ(BUFFER(msgbuf), 8, fp)) == 8) { 433 /* 434 * do the transformation 435 */ 436 MEMCPY(BUFFER(inbuf), BUFFER(msgbuf), 8); 437 DES_XFORM(UBUFFER(msgbuf)); 438 for (c = 0; c < 8; c++) 439 UCHAR(msgbuf, c) ^= UCHAR(ivec, c); 440 MEMCPY(BUFFER(ivec), BUFFER(inbuf), 8); 441 /* 442 * if the last one, handle it specially 443 */ 444 if ((c = fgetc(fp)) == EOF) { 445 n = CHAR(msgbuf, 7); 446 if (n < 0 || n > 7) { 447 des_error("decryption failed (block corrupted)"); 448 return EOF; 449 } 450 } else 451 (void)ungetc(c, fp); 452 return n; 453 } 454 if (n > 0) 455 des_error("decryption failed (incomplete block)"); 456 else if (n < 0) 457 des_error("cannot read file"); 458 return EOF; 459 } 460 #endif /* DES */ 461
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