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 * 4. 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 34#include <sys/cdefs.h> 35__FBSDID("$FreeBSD: releng/10.3/bin/ed/cbc.c 270756 2014-08-28 18:11:05Z pfg $"); 36 37#include <sys/types.h> 38#include <errno.h> 39#include <pwd.h> 40#ifdef DES 41#include <time.h> 42#include <openssl/des.h> 43#define ED_DES_INCLUDES 44#endif 45 46#include "ed.h" 47 48 49/* 50 * BSD and System V systems offer special library calls that do 51 * block move_liness and fills, so if possible we take advantage of them 52 */ 53#define MEMCPY(dest,src,len) memcpy((dest),(src),(len)) 54#define MEMZERO(dest,len) memset((dest), 0, (len)) 55 56/* Hide the calls to the primitive encryption routines. */ 57#define DES_XFORM(buf) \ 58 DES_ecb_encrypt(buf, buf, &schedule, \ 59 inverse ? DES_DECRYPT : DES_ENCRYPT); 60 61/* 62 * read/write - no error checking 63 */ 64#define READ(buf, n, fp) fread(buf, sizeof(char), n, fp) 65#define WRITE(buf, n, fp) fwrite(buf, sizeof(char), n, fp) 66 67/* 68 * global variables and related macros 69 */ 70 71#ifdef DES 72static DES_cblock ivec; /* initialization vector */ 73static DES_cblock pvec; /* padding vector */ 74 75static char bits[] = { /* used to extract bits from a char */ 76 '\200', '\100', '\040', '\020', '\010', '\004', '\002', '\001' 77}; 78 79static int pflag; /* 1 to preserve parity bits */ 80 81static DES_key_schedule schedule; /* expanded DES key */ 82 83static unsigned char des_buf[8];/* shared buffer for get_des_char/put_des_char */ 84static int des_ct = 0; /* count for get_des_char/put_des_char */ 85static int des_n = 0; /* index for put_des_char/get_des_char */ 86#endif 87 88/* init_des_cipher: initialize DES */ 89void 90init_des_cipher(void) 91{ 92#ifdef DES 93 int i; 94 95 des_ct = des_n = 0; 96 97 /* initialize the initialization vector */ 98 MEMZERO(ivec, 8); 99 100 /* initialize the padding vector */ 101 for (i = 0; i < 8; i++) 102 pvec[i] = (char) (arc4random() % 256); 103#endif 104} 105 106 107/* get_des_char: return next char in an encrypted file */ 108int 109get_des_char(FILE *fp) 110{ 111#ifdef DES 112 if (des_n >= des_ct) { 113 des_n = 0; 114 des_ct = cbc_decode(des_buf, fp); 115 } 116 return (des_ct > 0) ? des_buf[des_n++] : EOF; 117#else 118 return (getc(fp)); 119#endif 120} 121 122 123/* put_des_char: write a char to an encrypted file; return char written */ 124int 125put_des_char(int c, FILE *fp) 126{ 127#ifdef DES 128 if (des_n == sizeof des_buf) { 129 des_ct = cbc_encode(des_buf, des_n, fp); 130 des_n = 0; 131 } 132 return (des_ct >= 0) ? (des_buf[des_n++] = c) : EOF; 133#else 134 return (fputc(c, fp)); 135#endif 136} 137 138 139/* flush_des_file: flush an encrypted file's output; return status */ 140int 141flush_des_file(FILE *fp) 142{ 143#ifdef DES 144 if (des_n == sizeof des_buf) { 145 des_ct = cbc_encode(des_buf, des_n, fp); 146 des_n = 0; 147 } 148 return (des_ct >= 0 && cbc_encode(des_buf, des_n, fp) >= 0) ? 0 : EOF; 149#else 150 return (fflush(fp)); 151#endif 152} 153 154#ifdef DES 155/* 156 * get keyword from tty or stdin 157 */ 158int 159get_keyword(void) 160{ 161 char *p; /* used to obtain the key */ 162 DES_cblock msgbuf; /* I/O buffer */ 163 164 /* 165 * get the key 166 */ 167 if (*(p = getpass("Enter key: "))) { 168 169 /* 170 * copy it, nul-padded, into the key area 171 */ 172 expand_des_key(msgbuf, p); 173 MEMZERO(p, _PASSWORD_LEN); 174 set_des_key(&msgbuf); 175 MEMZERO(msgbuf, sizeof msgbuf); 176 return 1; 177 } 178 return 0; 179} 180 181 182/* 183 * print a warning message and, possibly, terminate 184 */ 185void 186des_error(const char *s) 187{ 188 errmsg = s ? s : strerror(errno); 189} 190 191/* 192 * map a hex character to an integer 193 */ 194int 195hex_to_binary(int c, int radix) 196{ 197 switch(c) { 198 case '0': return(0x0); 199 case '1': return(0x1); 200 case '2': return(radix > 2 ? 0x2 : -1); 201 case '3': return(radix > 3 ? 0x3 : -1); 202 case '4': return(radix > 4 ? 0x4 : -1); 203 case '5': return(radix > 5 ? 0x5 : -1); 204 case '6': return(radix > 6 ? 0x6 : -1); 205 case '7': return(radix > 7 ? 0x7 : -1); 206 case '8': return(radix > 8 ? 0x8 : -1); 207 case '9': return(radix > 9 ? 0x9 : -1); 208 case 'A': case 'a': return(radix > 10 ? 0xa : -1); 209 case 'B': case 'b': return(radix > 11 ? 0xb : -1); 210 case 'C': case 'c': return(radix > 12 ? 0xc : -1); 211 case 'D': case 'd': return(radix > 13 ? 0xd : -1); 212 case 'E': case 'e': return(radix > 14 ? 0xe : -1); 213 case 'F': case 'f': return(radix > 15 ? 0xf : -1); 214 } 215 /* 216 * invalid character 217 */ 218 return(-1); 219} 220 221/* 222 * convert the key to a bit pattern 223 * obuf bit pattern 224 * kbuf the key itself 225 */ 226void 227expand_des_key(char *obuf, char *kbuf) 228{ 229 int i, j; /* counter in a for loop */ 230 int nbuf[64]; /* used for hex/key translation */ 231 232 /* 233 * leading '0x' or '0X' == hex key 234 */ 235 if (kbuf[0] == '0' && (kbuf[1] == 'x' || kbuf[1] == 'X')) { 236 kbuf = &kbuf[2]; 237 /* 238 * now translate it, bombing on any illegal hex digit 239 */ 240 for (i = 0; i < 16 && kbuf[i]; i++) 241 if ((nbuf[i] = hex_to_binary((int) kbuf[i], 16)) == -1) 242 des_error("bad hex digit in key"); 243 while (i < 16) 244 nbuf[i++] = 0; 245 for (i = 0; i < 8; i++) 246 obuf[i] = 247 ((nbuf[2*i]&0xf)<<4) | (nbuf[2*i+1]&0xf); 248 /* preserve parity bits */ 249 pflag = 1; 250 return; 251 } 252 /* 253 * leading '0b' or '0B' == binary key 254 */ 255 if (kbuf[0] == '0' && (kbuf[1] == 'b' || kbuf[1] == 'B')) { 256 kbuf = &kbuf[2]; 257 /* 258 * now translate it, bombing on any illegal binary digit 259 */ 260 for (i = 0; kbuf[i] && i < 16; i++) 261 if ((nbuf[i] = hex_to_binary((int) kbuf[i], 2)) == -1) 262 des_error("bad binary digit in key"); 263 while (i < 64) 264 nbuf[i++] = 0; 265 for (i = 0; i < 8; i++) 266 for (j = 0; j < 8; j++) 267 obuf[i] = (obuf[i]<<1)|nbuf[8*i+j]; 268 /* preserve parity bits */ 269 pflag = 1; 270 return; 271 } 272 /* 273 * no special leader -- ASCII 274 */ 275 (void)strncpy(obuf, kbuf, 8); 276} 277 278/***************** 279 * DES FUNCTIONS * 280 *****************/ 281/* 282 * This sets the DES key and (if you're using the deszip version) 283 * the direction of the transformation. This uses the Sun 284 * to map the 64-bit key onto the 56 bits that the key schedule 285 * generation routines use: the old way, which just uses the user- 286 * supplied 64 bits as is, and the new way, which resets the parity 287 * bit to be the same as the low-order bit in each character. The 288 * new way generates a greater variety of key schedules, since many 289 * systems set the parity (high) bit of each character to 0, and the 290 * DES ignores the low order bit of each character. 291 */ 292void 293set_des_key(DES_cblock *buf) /* key block */ 294{ 295 int i, j; /* counter in a for loop */ 296 int par; /* parity counter */ 297 298 /* 299 * if the parity is not preserved, flip it 300 */ 301 if (!pflag) { 302 for (i = 0; i < 8; i++) { 303 par = 0; 304 for (j = 1; j < 8; j++) 305 if ((bits[j] & (*buf)[i]) != 0) 306 par++; 307 if ((par & 0x01) == 0x01) 308 (*buf)[i] &= 0x7f; 309 else 310 (*buf)[i] = ((*buf)[i] & 0x7f) | 0x80; 311 } 312 } 313 314 DES_set_odd_parity(buf); 315 DES_set_key(buf, &schedule); 316} 317 318 319/* 320 * This encrypts using the Cipher Block Chaining mode of DES 321 */ 322int 323cbc_encode(unsigned char *msgbuf, int n, FILE *fp) 324{ 325 int inverse = 0; /* 0 to encrypt, 1 to decrypt */ 326 327 /* 328 * do the transformation 329 */ 330 if (n == 8) { 331 for (n = 0; n < 8; n++) 332 msgbuf[n] ^= ivec[n]; 333 DES_XFORM((DES_cblock *)msgbuf); 334 MEMCPY(ivec, msgbuf, 8); 335 return WRITE(msgbuf, 8, fp); 336 } 337 /* 338 * at EOF or last block -- in either case, the last byte contains 339 * the character representation of the number of bytes in it 340 */ 341/* 342 MEMZERO(msgbuf + n, 8 - n); 343*/ 344 /* 345 * Pad the last block randomly 346 */ 347 (void)MEMCPY(msgbuf + n, pvec, 8 - n); 348 msgbuf[7] = n; 349 for (n = 0; n < 8; n++) 350 msgbuf[n] ^= ivec[n]; 351 DES_XFORM((DES_cblock *)msgbuf); 352 return WRITE(msgbuf, 8, fp); 353} 354 355/* 356 * This decrypts using the Cipher Block Chaining mode of DES 357 * msgbuf I/O buffer 358 * fp input file descriptor 359 */ 360int 361cbc_decode(unsigned char *msgbuf, FILE *fp) 362{ 363 DES_cblock tbuf; /* temp buffer for initialization vector */ 364 int n; /* number of bytes actually read */ 365 int c; /* used to test for EOF */ 366 int inverse = 1; /* 0 to encrypt, 1 to decrypt */ 367 368 if ((n = READ(msgbuf, 8, fp)) == 8) { 369 /* 370 * do the transformation 371 */ 372 MEMCPY(tbuf, msgbuf, 8); 373 DES_XFORM((DES_cblock *)msgbuf); 374 for (c = 0; c < 8; c++) 375 msgbuf[c] ^= ivec[c]; 376 MEMCPY(ivec, tbuf, 8); 377 /* 378 * if the last one, handle it specially 379 */ 380 if ((c = fgetc(fp)) == EOF) { 381 n = msgbuf[7]; 382 if (n < 0 || n > 7) { 383 des_error("decryption failed (block corrupted)"); 384 return EOF; 385 } 386 } else 387 (void)ungetc(c, fp); 388 return n; 389 } 390 if (n > 0) 391 des_error("decryption failed (incomplete block)"); 392 else if (n < 0) 393 des_error("cannot read file"); 394 return EOF; 395} 396#endif /* DES */ 397