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: head/bin/ed/cbc.c 248656 2013-03-23 19:04:57Z jmg $ 37 */ 38 39 #include <sys/types.h> 40 #include <errno.h> 41 #include <pwd.h> 42 #ifdef DES 43 #include <time.h> 44 #include <openssl/des.h> 45 #define ED_DES_INCLUDES 46 #endif 47 48 #include "ed.h" 49 50 51 /* 52 * BSD and System V systems offer special library calls that do 53 * block move_liness and fills, so if possible we take advantage of them 54 */ 55 #define MEMCPY(dest,src,len) memcpy((dest),(src),(len)) 56 #define MEMZERO(dest,len) memset((dest), 0, (len)) 57 58 /* Hide the calls to the primitive encryption routines. */ 59 #define DES_XFORM(buf) \ 60 DES_ecb_encrypt(buf, buf, &schedule, \ 61 inverse ? DES_DECRYPT : DES_ENCRYPT); 62 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 #ifdef DES 74 static DES_cblock ivec; /* initialization vector */ 75 static DES_cblock pvec; /* padding vector */ 76 77 static char bits[] = { /* used to extract bits from a char */ 78 '\200', '\100', '\040', '\020', '\010', '\004', '\002', '\001' 79 }; 80 81 static int pflag; /* 1 to preserve parity bits */ 82 83 static DES_key_schedule schedule; /* expanded DES key */ 84 85 static unsigned char des_buf[8];/* shared buffer for get_des_char/put_des_char */ 86 static int des_ct = 0; /* count for get_des_char/put_des_char */ 87 static int des_n = 0; /* index for put_des_char/get_des_char */ 88 #endif 89 90 /* init_des_cipher: initialize DES */ 91 void 92 init_des_cipher(void) 93 { 94 #ifdef DES 95 int i; 96 97 des_ct = des_n = 0; 98 99 /* initialize the initialization vector */ 100 MEMZERO(ivec, 8); 101 102 /* initialize the padding vector */ 103 for (i = 0; i < 8; i++) 104 pvec[i] = (char) (arc4random() % 256); 105 #endif 106 } 107 108 109 /* get_des_char: return next char in an encrypted file */ 110 int 111 get_des_char(FILE *fp) 112 { 113 #ifdef DES 114 if (des_n >= des_ct) { 115 des_n = 0; 116 des_ct = cbc_decode(des_buf, fp); 117 } 118 return (des_ct > 0) ? des_buf[des_n++] : EOF; 119 #else 120 return (getc(fp)); 121 #endif 122 } 123 124 125 /* put_des_char: write a char to an encrypted file; return char written */ 126 int 127 put_des_char(int c, FILE *fp) 128 { 129 #ifdef DES 130 if (des_n == sizeof des_buf) { 131 des_ct = cbc_encode(des_buf, des_n, fp); 132 des_n = 0; 133 } 134 return (des_ct >= 0) ? (des_buf[des_n++] = c) : EOF; 135 #else 136 return (fputc(c, fp)); 137 #endif 138 } 139 140 141 /* flush_des_file: flush an encrypted file's output; return status */ 142 int 143 flush_des_file(FILE *fp) 144 { 145 #ifdef DES 146 if (des_n == sizeof des_buf) { 147 des_ct = cbc_encode(des_buf, des_n, fp); 148 des_n = 0; 149 } 150 return (des_ct >= 0 && cbc_encode(des_buf, des_n, fp) >= 0) ? 0 : EOF; 151 #else 152 return (fflush(fp)); 153 #endif 154 } 155 156 #ifdef DES 157 /* 158 * get keyword from tty or stdin 159 */ 160 int 161 get_keyword(void) 162 { 163 char *p; /* used to obtain the key */ 164 DES_cblock msgbuf; /* I/O buffer */ 165 166 /* 167 * get the key 168 */ 169 if (*(p = getpass("Enter key: "))) { 170 171 /* 172 * copy it, nul-padded, into the key area 173 */ 174 expand_des_key(msgbuf, p); 175 MEMZERO(p, _PASSWORD_LEN); 176 set_des_key(&msgbuf); 177 MEMZERO(msgbuf, sizeof msgbuf); 178 return 1; 179 } 180 return 0; 181 } 182 183 184 /* 185 * print a warning message and, possibly, terminate 186 */ 187 void 188 des_error(const char *s) 189 { 190 errmsg = s ? s : strerror(errno); 191 } 192 193 /* 194 * map a hex character to an integer 195 */ 196 int 197 hex_to_binary(int c, int radix) 198 { 199 switch(c) { 200 case '0': return(0x0); 201 case '1': return(0x1); 202 case '2': return(radix > 2 ? 0x2 : -1); 203 case '3': return(radix > 3 ? 0x3 : -1); 204 case '4': return(radix > 4 ? 0x4 : -1); 205 case '5': return(radix > 5 ? 0x5 : -1); 206 case '6': return(radix > 6 ? 0x6 : -1); 207 case '7': return(radix > 7 ? 0x7 : -1); 208 case '8': return(radix > 8 ? 0x8 : -1); 209 case '9': return(radix > 9 ? 0x9 : -1); 210 case 'A': case 'a': return(radix > 10 ? 0xa : -1); 211 case 'B': case 'b': return(radix > 11 ? 0xb : -1); 212 case 'C': case 'c': return(radix > 12 ? 0xc : -1); 213 case 'D': case 'd': return(radix > 13 ? 0xd : -1); 214 case 'E': case 'e': return(radix > 14 ? 0xe : -1); 215 case 'F': case 'f': return(radix > 15 ? 0xf : -1); 216 } 217 /* 218 * invalid character 219 */ 220 return(-1); 221 } 222 223 /* 224 * convert the key to a bit pattern 225 * obuf bit pattern 226 * kbuf the key itself 227 */ 228 void 229 expand_des_key(char *obuf, char *kbuf) 230 { 231 int i, j; /* counter in a for loop */ 232 int nbuf[64]; /* used for hex/key translation */ 233 234 /* 235 * leading '0x' or '0X' == hex key 236 */ 237 if (kbuf[0] == '0' && (kbuf[1] == 'x' || kbuf[1] == 'X')) { 238 kbuf = &kbuf[2]; 239 /* 240 * now translate it, bombing on any illegal hex digit 241 */ 242 for (i = 0; i < 16 && kbuf[i]; i++) 243 if ((nbuf[i] = hex_to_binary((int) kbuf[i], 16)) == -1) 244 des_error("bad hex digit in key"); 245 while (i < 16) 246 nbuf[i++] = 0; 247 for (i = 0; i < 8; i++) 248 obuf[i] = 249 ((nbuf[2*i]&0xf)<<4) | (nbuf[2*i+1]&0xf); 250 /* preserve parity bits */ 251 pflag = 1; 252 return; 253 } 254 /* 255 * leading '0b' or '0B' == binary key 256 */ 257 if (kbuf[0] == '0' && (kbuf[1] == 'b' || kbuf[1] == 'B')) { 258 kbuf = &kbuf[2]; 259 /* 260 * now translate it, bombing on any illegal binary digit 261 */ 262 for (i = 0; i < 16 && kbuf[i]; i++) 263 if ((nbuf[i] = hex_to_binary((int) kbuf[i], 2)) == -1) 264 des_error("bad binary digit in key"); 265 while (i < 64) 266 nbuf[i++] = 0; 267 for (i = 0; i < 8; i++) 268 for (j = 0; j < 8; j++) 269 obuf[i] = (obuf[i]<<1)|nbuf[8*i+j]; 270 /* preserve parity bits */ 271 pflag = 1; 272 return; 273 } 274 /* 275 * no special leader -- ASCII 276 */ 277 strncpy(obuf, kbuf, 8); 278 } 279 280 /***************** 281 * DES FUNCTIONS * 282 *****************/ 283 /* 284 * This sets the DES key and (if you're using the deszip version) 285 * the direction of the transformation. This uses the Sun 286 * to map the 64-bit key onto the 56 bits that the key schedule 287 * generation routines use: the old way, which just uses the user- 288 * supplied 64 bits as is, and the new way, which resets the parity 289 * bit to be the same as the low-order bit in each character. The 290 * new way generates a greater variety of key schedules, since many 291 * systems set the parity (high) bit of each character to 0, and the 292 * DES ignores the low order bit of each character. 293 */ 294 void 295 set_des_key(DES_cblock *buf) /* key block */ 296 { 297 int i, j; /* counter in a for loop */ 298 int par; /* parity counter */ 299 300 /* 301 * if the parity is not preserved, flip it 302 */ 303 if (!pflag) { 304 for (i = 0; i < 8; i++) { 305 par = 0; 306 for (j = 1; j < 8; j++) 307 if ((bits[j] & (*buf)[i]) != 0) 308 par++; 309 if ((par & 0x01) == 0x01) 310 (*buf)[i] &= 0x7f; 311 else 312 (*buf)[i] = ((*buf)[i] & 0x7f) | 0x80; 313 } 314 } 315 316 DES_set_odd_parity(buf); 317 DES_set_key(buf, &schedule); 318 } 319 320 321 /* 322 * This encrypts using the Cipher Block Chaining mode of DES 323 */ 324 int 325 cbc_encode(unsigned char *msgbuf, int n, FILE *fp) 326 { 327 int inverse = 0; /* 0 to encrypt, 1 to decrypt */ 328 329 /* 330 * do the transformation 331 */ 332 if (n == 8) { 333 for (n = 0; n < 8; n++) 334 msgbuf[n] ^= ivec[n]; 335 DES_XFORM((DES_cblock *)msgbuf); 336 MEMCPY(ivec, msgbuf, 8); 337 return WRITE(msgbuf, 8, fp); 338 } 339 /* 340 * at EOF or last block -- in either case, the last byte contains 341 * the character representation of the number of bytes in it 342 */ 343 /* 344 MEMZERO(msgbuf + n, 8 - n); 345 */ 346 /* 347 * Pad the last block randomly 348 */ 349 MEMCPY(msgbuf + n, pvec, 8 - n); 350 msgbuf[7] = n; 351 for (n = 0; n < 8; n++) 352 msgbuf[n] ^= ivec[n]; 353 DES_XFORM((DES_cblock *)msgbuf); 354 return WRITE(msgbuf, 8, fp); 355 } 356 357 /* 358 * This decrypts using the Cipher Block Chaining mode of DES 359 * msgbuf I/O buffer 360 * fp input file descriptor 361 */ 362 int 363 cbc_decode(unsigned char *msgbuf, FILE *fp) 364 { 365 DES_cblock tbuf; /* temp buffer for initialization vector */ 366 int n; /* number of bytes actually read */ 367 int c; /* used to test for EOF */ 368 int inverse = 1; /* 0 to encrypt, 1 to decrypt */ 369 370 if ((n = READ(msgbuf, 8, fp)) == 8) { 371 /* 372 * do the transformation 373 */ 374 MEMCPY(tbuf, msgbuf, 8); 375 DES_XFORM((DES_cblock *)msgbuf); 376 for (c = 0; c < 8; c++) 377 msgbuf[c] ^= ivec[c]; 378 MEMCPY(ivec, tbuf, 8); 379 /* 380 * if the last one, handle it specially 381 */ 382 if ((c = fgetc(fp)) == EOF) { 383 n = msgbuf[7]; 384 if (n < 0 || n > 7) { 385 des_error("decryption failed (block corrupted)"); 386 return EOF; 387 } 388 } else 389 ungetc(c, fp); 390 return n; 391 } 392 if (n > 0) 393 des_error("decryption failed (incomplete block)"); 394 else if (n < 0) 395 des_error("cannot read file"); 396 return EOF; 397 } 398 #endif /* DES */ 399