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 * 3. 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 * from: @(#)bdes.c 5.5 (Berkeley) 6/27/91 34 * 35 * @(#)cbc.c,v 1.2 1994/02/01 00:34:36 alm Exp 36 * $FreeBSD: src/bin/ed/cbc.c,v 1.20 2004/04/06 20:06:47 markm Exp $ 37 * $DragonFly: src/bin/ed/cbc.c,v 1.10 2007/04/06 23:36:54 pavalos Exp $ 38 */ 39 40 #include <sys/types.h> 41 #include <errno.h> 42 #include <pwd.h> 43 #ifdef DES 44 #include <time.h> 45 #include <openssl/des.h> 46 #define ED_DES_INCLUDES 47 #endif 48 49 #include "ed.h" 50 51 52 /* 53 * BSD and System V systems offer special library calls that do 54 * block move_liness and fills, so if possible we take advantage of them 55 */ 56 #define MEMCPY(dest,src,len) memcpy((dest),(src),(len)) 57 #define MEMZERO(dest,len) memset((dest), 0, (len)) 58 59 /* Hide the calls to the primitive encryption routines. */ 60 #define DES_XFORM(buf) \ 61 DES_ecb_encrypt(buf, buf, &schedule, \ 62 inverse ? DES_DECRYPT : DES_ENCRYPT); 63 /* 64 * read/write - no error checking 65 */ 66 #define READ(buf, n, fp) fread(buf, sizeof(char), n, fp) 67 #define WRITE(buf, n, fp) fwrite(buf, sizeof(char), n, fp) 68 69 /* 70 * global variables and related macros 71 */ 72 73 enum { /* encrypt, decrypt, authenticate */ 74 MODE_ENCRYPT, MODE_DECRYPT, MODE_AUTHENTICATE 75 } mode = MODE_ENCRYPT; 76 77 #ifdef DES 78 DES_cblock ivec; /* initialization vector */ 79 DES_cblock pvec; /* padding vector */ 80 #endif 81 82 char bits[] = { /* used to extract bits from a char */ 83 '\200', '\100', '\040', '\020', '\010', '\004', '\002', '\001' 84 }; 85 86 int pflag; /* 1 to preserve parity bits */ 87 88 #ifdef DES 89 DES_key_schedule schedule; /* expanded DES key */ 90 #endif 91 92 char des_buf[8]; /* shared buffer for get_des_char/put_des_char */ 93 int des_ct = 0; /* count for get_des_char/put_des_char */ 94 int des_n = 0; /* index for put_des_char/get_des_char */ 95 96 97 /* init_des_cipher: initialize DES */ 98 void 99 init_des_cipher(void) 100 { 101 #ifdef DES 102 int i; 103 104 des_ct = des_n = 0; 105 106 /* initialize the initialization vector */ 107 MEMZERO(ivec, 8); 108 109 /* initialize the padding vector */ 110 for (i = 0; i < 8; i++) 111 pvec[i] = (char) (arc4random() % 256); 112 #endif 113 } 114 115 116 /* get_des_char: return next char in an encrypted file */ 117 int 118 get_des_char(FILE *fp) 119 { 120 #ifdef DES 121 if (des_n >= des_ct) { 122 des_n = 0; 123 des_ct = cbc_decode(des_buf, fp); 124 } 125 return (des_ct > 0) ? (unsigned char)des_buf[des_n++] : EOF; 126 #else 127 return (getc(fp)); 128 #endif 129 } 130 131 132 /* put_des_char: write a char to an encrypted file; return char written */ 133 int 134 put_des_char(int c, FILE *fp) 135 { 136 #ifdef DES 137 if (des_n == sizeof des_buf) { 138 des_ct = cbc_encode(des_buf, des_n, fp); 139 des_n = 0; 140 } 141 return (des_ct >= 0) ? (des_buf[des_n++] = (char)c) : EOF; 142 #else 143 return (fputc(c, fp)); 144 #endif 145 } 146 147 148 /* flush_des_file: flush an encrypted file's output; return status */ 149 int 150 flush_des_file(FILE *fp) 151 { 152 #ifdef DES 153 if (des_n == sizeof des_buf) { 154 des_ct = cbc_encode(des_buf, des_n, fp); 155 des_n = 0; 156 } 157 return (des_ct >= 0 && cbc_encode(des_buf, des_n, fp) >= 0) ? 0 : EOF; 158 #else 159 return (fflush(fp)); 160 #endif 161 } 162 163 #ifdef DES 164 /* 165 * get keyword from tty or stdin 166 */ 167 int 168 get_keyword(void) 169 { 170 char *p; /* used to obtain the key */ 171 DES_cblock msgbuf; /* I/O buffer */ 172 173 /* 174 * get the key 175 */ 176 if (*(p = getpass("Enter key: "))) { 177 178 /* 179 * copy it, nul-padded, into the key area 180 */ 181 expand_des_key(msgbuf, p); 182 MEMZERO(p, _PASSWORD_LEN); 183 set_des_key(&msgbuf); 184 MEMZERO(msgbuf, sizeof msgbuf); 185 return 1; 186 } 187 return 0; 188 } 189 190 191 /* 192 * print a warning message and, possibly, terminate 193 */ 194 void 195 des_error(const char *s) 196 { 197 errmsg = s ? s : strerror(errno); 198 } 199 200 /* 201 * map a hex character to an integer 202 */ 203 int 204 hex_to_binary(int c, int radix) 205 { 206 switch(c) { 207 case '0': return(0x0); 208 case '1': return(0x1); 209 case '2': return(radix > 2 ? 0x2 : -1); 210 case '3': return(radix > 3 ? 0x3 : -1); 211 case '4': return(radix > 4 ? 0x4 : -1); 212 case '5': return(radix > 5 ? 0x5 : -1); 213 case '6': return(radix > 6 ? 0x6 : -1); 214 case '7': return(radix > 7 ? 0x7 : -1); 215 case '8': return(radix > 8 ? 0x8 : -1); 216 case '9': return(radix > 9 ? 0x9 : -1); 217 case 'A': case 'a': return(radix > 10 ? 0xa : -1); 218 case 'B': case 'b': return(radix > 11 ? 0xb : -1); 219 case 'C': case 'c': return(radix > 12 ? 0xc : -1); 220 case 'D': case 'd': return(radix > 13 ? 0xd : -1); 221 case 'E': case 'e': return(radix > 14 ? 0xe : -1); 222 case 'F': case 'f': return(radix > 15 ? 0xf : -1); 223 } 224 /* 225 * invalid character 226 */ 227 return(-1); 228 } 229 230 /* 231 * convert the key to a bit pattern 232 * obuf bit pattern 233 * inbuf the key itself 234 */ 235 void 236 expand_des_key(char *obuf, char *inbuf) 237 { 238 int i, j; /* counter in a for loop */ 239 int nbuf[64]; /* used for hex/key translation */ 240 241 /* 242 * leading '0x' or '0X' == hex key 243 */ 244 if (inbuf[0] == '0' && (inbuf[1] == 'x' || inbuf[1] == 'X')) { 245 inbuf = &inbuf[2]; 246 /* 247 * now translate it, bombing on any illegal hex digit 248 */ 249 for (i = 0; inbuf[i] && i < 16; i++) 250 if ((nbuf[i] = hex_to_binary((int) inbuf[i], 16)) == -1) 251 des_error("bad hex digit in key"); 252 while (i < 16) 253 nbuf[i++] = 0; 254 for (i = 0; i < 8; i++) 255 obuf[i] = 256 ((nbuf[2*i]&0xf)<<4) | (nbuf[2*i+1]&0xf); 257 /* preserve parity bits */ 258 pflag = 1; 259 return; 260 } 261 /* 262 * leading '0b' or '0B' == binary key 263 */ 264 if (inbuf[0] == '0' && (inbuf[1] == 'b' || inbuf[1] == 'B')) { 265 inbuf = &inbuf[2]; 266 /* 267 * now translate it, bombing on any illegal binary digit 268 */ 269 for (i = 0; inbuf[i] && i < 16; i++) 270 if ((nbuf[i] = hex_to_binary((int) inbuf[i], 2)) == -1) 271 des_error("bad binary digit in key"); 272 while (i < 64) 273 nbuf[i++] = 0; 274 for (i = 0; i < 8; i++) 275 for (j = 0; j < 8; j++) 276 obuf[i] = (obuf[i]<<1)|nbuf[8*i+j]; 277 /* preserve parity bits */ 278 pflag = 1; 279 return; 280 } 281 /* 282 * no special leader -- ASCII 283 */ 284 strncpy(obuf, inbuf, 8); 285 } 286 287 /***************** 288 * DES FUNCTIONS * 289 *****************/ 290 /* 291 * This sets the DES key and (if you're using the deszip version) 292 * the direction of the transformation. This uses the Sun 293 * to map the 64-bit key onto the 56 bits that the key schedule 294 * generation routines use: the old way, which just uses the user- 295 * supplied 64 bits as is, and the new way, which resets the parity 296 * bit to be the same as the low-order bit in each character. The 297 * new way generates a greater variety of key schedules, since many 298 * systems set the parity (high) bit of each character to 0, and the 299 * DES ignores the low order bit of each character. 300 */ 301 void 302 set_des_key(DES_cblock *buf) /* key block */ 303 { 304 int i, j; /* counter in a for loop */ 305 int par; /* parity counter */ 306 307 /* 308 * if the parity is not preserved, flip it 309 */ 310 if (!pflag) { 311 for (i = 0; i < 8; i++) { 312 par = 0; 313 for (j = 1; j < 8; j++) 314 if ((bits[j] & (*buf)[i]) != 0) 315 par++; 316 if ((par & 0x01) == 0x01) 317 (*buf)[i] &= 0x7f; 318 else 319 (*buf)[i] = ((*buf)[i] & 0x7f) | 0x80; 320 } 321 } 322 323 DES_set_odd_parity(buf); 324 DES_set_key(buf, &schedule); 325 } 326 327 328 /* 329 * This encrypts using the Cipher Block Chaining mode of DES 330 */ 331 int 332 cbc_encode(char *msgbuf, int n, FILE *fp) 333 { 334 int inverse = 0; /* 0 to encrypt, 1 to decrypt */ 335 336 /* 337 * do the transformation 338 */ 339 if (n == 8) { 340 for (n = 0; n < 8; n++) 341 msgbuf[n] ^= ivec[n]; 342 DES_XFORM((DES_cblock *)msgbuf); 343 MEMCPY(ivec, msgbuf, 8); 344 return WRITE(msgbuf, 8, fp); 345 } 346 /* 347 * at EOF or last block -- in either case, the last byte contains 348 * the character representation of the number of bytes in it 349 */ 350 /* 351 MEMZERO(msgbuf + n, 8 - n); 352 */ 353 /* 354 * Pad the last block randomly 355 */ 356 MEMCPY(msgbuf + n, pvec, 8 - n); 357 msgbuf[7] = n; 358 for (n = 0; n < 8; n++) 359 msgbuf[n] ^= ivec[n]; 360 DES_XFORM((DES_cblock *)msgbuf); 361 return WRITE(msgbuf, 8, fp); 362 } 363 364 /* 365 * This decrypts using the Cipher Block Chaining mode of DES 366 * msgbuf I/O buffer 367 * fp input file descriptor 368 */ 369 int 370 cbc_decode(char *msgbuf, FILE *fp) 371 { 372 DES_cblock inbuf; /* temp buffer for initialization vector */ 373 int n; /* number of bytes actually read */ 374 int c; /* used to test for EOF */ 375 int inverse = 1; /* 0 to encrypt, 1 to decrypt */ 376 377 if ((n = READ(msgbuf, 8, fp)) == 8) { 378 /* 379 * do the transformation 380 */ 381 MEMCPY(inbuf, msgbuf, 8); 382 DES_XFORM((DES_cblock *)msgbuf); 383 for (c = 0; c < 8; c++) 384 msgbuf[c] ^= ivec[c]; 385 MEMCPY(ivec, inbuf, 8); 386 /* 387 * if the last one, handle it specially 388 */ 389 if ((c = fgetc(fp)) == EOF) { 390 n = msgbuf[7]; 391 if (n < 0 || n > 7) { 392 des_error("decryption failed (block corrupted)"); 393 return EOF; 394 } 395 } else 396 ungetc(c, fp); 397 return n; 398 } 399 if (n > 0) 400 des_error("decryption failed (incomplete block)"); 401 else if (n < 0) 402 des_error("cannot read file"); 403 return EOF; 404 } 405 #endif /* DES */ 406