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 300340 2016-05-21 00:45:42Z pfg $ 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 des_ct = des_n = 0; 96 97 /* initialize the initialization vector */ 98 MEMZERO(ivec, 8); 99 100 /* initialize the padding vector */ 101 arc4random_buf(pvec, sizeof(pvec)); 102 #endif 103 } 104 105 106 /* get_des_char: return next char in an encrypted file */ 107 int 108 get_des_char(FILE *fp) 109 { 110 #ifdef DES 111 if (des_n >= des_ct) { 112 des_n = 0; 113 des_ct = cbc_decode(des_buf, fp); 114 } 115 return (des_ct > 0) ? des_buf[des_n++] : EOF; 116 #else 117 return (getc(fp)); 118 #endif 119 } 120 121 122 /* put_des_char: write a char to an encrypted file; return char written */ 123 int 124 put_des_char(int c, FILE *fp) 125 { 126 #ifdef DES 127 if (des_n == sizeof des_buf) { 128 des_ct = cbc_encode(des_buf, des_n, fp); 129 des_n = 0; 130 } 131 return (des_ct >= 0) ? (des_buf[des_n++] = c) : EOF; 132 #else 133 return (fputc(c, fp)); 134 #endif 135 } 136 137 138 /* flush_des_file: flush an encrypted file's output; return status */ 139 int 140 flush_des_file(FILE *fp) 141 { 142 #ifdef DES 143 if (des_n == sizeof des_buf) { 144 des_ct = cbc_encode(des_buf, des_n, fp); 145 des_n = 0; 146 } 147 return (des_ct >= 0 && cbc_encode(des_buf, des_n, fp) >= 0) ? 0 : EOF; 148 #else 149 return (fflush(fp)); 150 #endif 151 } 152 153 #ifdef DES 154 /* 155 * get keyword from tty or stdin 156 */ 157 int 158 get_keyword(void) 159 { 160 char *p; /* used to obtain the key */ 161 DES_cblock msgbuf; /* I/O buffer */ 162 163 /* 164 * get the key 165 */ 166 if ((p = getpass("Enter key: ")) != NULL && *p != '\0') { 167 168 /* 169 * copy it, nul-padded, into the key area 170 */ 171 expand_des_key(msgbuf, p); 172 MEMZERO(p, _PASSWORD_LEN); 173 set_des_key(&msgbuf); 174 MEMZERO(msgbuf, sizeof msgbuf); 175 return 1; 176 } 177 return 0; 178 } 179 180 181 /* 182 * print a warning message and, possibly, terminate 183 */ 184 void 185 des_error(const char *s) 186 { 187 errmsg = s ? s : strerror(errno); 188 } 189 190 /* 191 * map a hex character to an integer 192 */ 193 int 194 hex_to_binary(int c, int radix) 195 { 196 switch(c) { 197 case '0': return(0x0); 198 case '1': return(0x1); 199 case '2': return(radix > 2 ? 0x2 : -1); 200 case '3': return(radix > 3 ? 0x3 : -1); 201 case '4': return(radix > 4 ? 0x4 : -1); 202 case '5': return(radix > 5 ? 0x5 : -1); 203 case '6': return(radix > 6 ? 0x6 : -1); 204 case '7': return(radix > 7 ? 0x7 : -1); 205 case '8': return(radix > 8 ? 0x8 : -1); 206 case '9': return(radix > 9 ? 0x9 : -1); 207 case 'A': case 'a': return(radix > 10 ? 0xa : -1); 208 case 'B': case 'b': return(radix > 11 ? 0xb : -1); 209 case 'C': case 'c': return(radix > 12 ? 0xc : -1); 210 case 'D': case 'd': return(radix > 13 ? 0xd : -1); 211 case 'E': case 'e': return(radix > 14 ? 0xe : -1); 212 case 'F': case 'f': return(radix > 15 ? 0xf : -1); 213 } 214 /* 215 * invalid character 216 */ 217 return(-1); 218 } 219 220 /* 221 * convert the key to a bit pattern 222 * obuf bit pattern 223 * kbuf the key itself 224 */ 225 void 226 expand_des_key(char *obuf, char *kbuf) 227 { 228 int i, j; /* counter in a for loop */ 229 int nbuf[64]; /* used for hex/key translation */ 230 231 /* 232 * leading '0x' or '0X' == hex key 233 */ 234 if (kbuf[0] == '0' && (kbuf[1] == 'x' || kbuf[1] == 'X')) { 235 kbuf = &kbuf[2]; 236 /* 237 * now translate it, bombing on any illegal hex digit 238 */ 239 for (i = 0; i < 16 && kbuf[i]; i++) 240 if ((nbuf[i] = hex_to_binary((int) kbuf[i], 16)) == -1) 241 des_error("bad hex digit in key"); 242 while (i < 16) 243 nbuf[i++] = 0; 244 for (i = 0; i < 8; i++) 245 obuf[i] = 246 ((nbuf[2*i]&0xf)<<4) | (nbuf[2*i+1]&0xf); 247 /* preserve parity bits */ 248 pflag = 1; 249 return; 250 } 251 /* 252 * leading '0b' or '0B' == binary key 253 */ 254 if (kbuf[0] == '0' && (kbuf[1] == 'b' || kbuf[1] == 'B')) { 255 kbuf = &kbuf[2]; 256 /* 257 * now translate it, bombing on any illegal binary digit 258 */ 259 for (i = 0; i < 16 && kbuf[i]; i++) 260 if ((nbuf[i] = hex_to_binary((int) kbuf[i], 2)) == -1) 261 des_error("bad binary digit in key"); 262 while (i < 64) 263 nbuf[i++] = 0; 264 for (i = 0; i < 8; i++) 265 for (j = 0; j < 8; j++) 266 obuf[i] = (obuf[i]<<1)|nbuf[8*i+j]; 267 /* preserve parity bits */ 268 pflag = 1; 269 return; 270 } 271 /* 272 * no special leader -- ASCII 273 */ 274 strncpy(obuf, kbuf, 8); 275 } 276 277 /***************** 278 * DES FUNCTIONS * 279 *****************/ 280 /* 281 * This sets the DES key and (if you're using the deszip version) 282 * the direction of the transformation. This uses the Sun 283 * to map the 64-bit key onto the 56 bits that the key schedule 284 * generation routines use: the old way, which just uses the user- 285 * supplied 64 bits as is, and the new way, which resets the parity 286 * bit to be the same as the low-order bit in each character. The 287 * new way generates a greater variety of key schedules, since many 288 * systems set the parity (high) bit of each character to 0, and the 289 * DES ignores the low order bit of each character. 290 */ 291 void 292 set_des_key(DES_cblock *buf) /* key block */ 293 { 294 int i, j; /* counter in a for loop */ 295 int par; /* parity counter */ 296 297 /* 298 * if the parity is not preserved, flip it 299 */ 300 if (!pflag) { 301 for (i = 0; i < 8; i++) { 302 par = 0; 303 for (j = 1; j < 8; j++) 304 if ((bits[j] & (*buf)[i]) != 0) 305 par++; 306 if ((par & 0x01) == 0x01) 307 (*buf)[i] &= 0x7f; 308 else 309 (*buf)[i] = ((*buf)[i] & 0x7f) | 0x80; 310 } 311 } 312 313 DES_set_odd_parity(buf); 314 DES_set_key(buf, &schedule); 315 } 316 317 318 /* 319 * This encrypts using the Cipher Block Chaining mode of DES 320 */ 321 int 322 cbc_encode(unsigned char *msgbuf, int n, FILE *fp) 323 { 324 int inverse = 0; /* 0 to encrypt, 1 to decrypt */ 325 326 /* 327 * do the transformation 328 */ 329 if (n == 8) { 330 for (n = 0; n < 8; n++) 331 msgbuf[n] ^= ivec[n]; 332 DES_XFORM((DES_cblock *)msgbuf); 333 MEMCPY(ivec, msgbuf, 8); 334 return WRITE(msgbuf, 8, fp); 335 } 336 /* 337 * at EOF or last block -- in either case, the last byte contains 338 * the character representation of the number of bytes in it 339 */ 340 /* 341 MEMZERO(msgbuf + n, 8 - n); 342 */ 343 /* 344 * Pad the last block randomly 345 */ 346 MEMCPY(msgbuf + n, pvec, 8 - n); 347 msgbuf[7] = n; 348 for (n = 0; n < 8; n++) 349 msgbuf[n] ^= ivec[n]; 350 DES_XFORM((DES_cblock *)msgbuf); 351 return WRITE(msgbuf, 8, fp); 352 } 353 354 /* 355 * This decrypts using the Cipher Block Chaining mode of DES 356 * msgbuf I/O buffer 357 * fp input file descriptor 358 */ 359 int 360 cbc_decode(unsigned char *msgbuf, FILE *fp) 361 { 362 DES_cblock tbuf; /* temp buffer for initialization vector */ 363 int n; /* number of bytes actually read */ 364 int c; /* used to test for EOF */ 365 int inverse = 1; /* 0 to encrypt, 1 to decrypt */ 366 367 if ((n = READ(msgbuf, 8, fp)) == 8) { 368 /* 369 * do the transformation 370 */ 371 MEMCPY(tbuf, msgbuf, 8); 372 DES_XFORM((DES_cblock *)msgbuf); 373 for (c = 0; c < 8; c++) 374 msgbuf[c] ^= ivec[c]; 375 MEMCPY(ivec, tbuf, 8); 376 /* 377 * if the last one, handle it specially 378 */ 379 if ((c = fgetc(fp)) == EOF) { 380 n = msgbuf[7]; 381 if (n < 0 || n > 7) { 382 des_error("decryption failed (block corrupted)"); 383 return EOF; 384 } 385 } else 386 ungetc(c, fp); 387 return n; 388 } 389 if (n > 0) 390 des_error("decryption failed (incomplete block)"); 391 else if (n < 0) 392 des_error("cannot read file"); 393 return EOF; 394 } 395 #endif /* DES */ 396