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54a7a3ed AM |
1 | /* cbc.c: This file contains the encryption routines for the ed line editor */ |
2 | /*- | |
84ee7b23 | 3 | * Copyright (c) 1993 The Regents of the University of California. |
54a7a3ed AM |
4 | * All rights reserved. |
5 | * | |
84ee7b23 AM |
6 | * Copyright (c) 1993 Andrew Moore, Talke Studio. |
7 | * All rights reserved. | |
54a7a3ed AM |
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. All advertising materials mentioning features or use of this software | |
18 | * must display the following acknowledgement: | |
19 | * This product includes software developed by the University of | |
20 | * California, Berkeley and its contributors. | |
21 | * 4. Neither the name of the University nor the names of its contributors | |
22 | * may be used to endorse or promote products derived from this software | |
23 | * without specific prior written permission. | |
24 | * | |
25 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
26 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
27 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
28 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
29 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
30 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
31 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
32 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
33 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
34 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
35 | * SUCH DAMAGE. | |
84ee7b23 AM |
36 | * |
37 | * from: @(#)bdes.c 5.5 (Berkeley) 6/27/91 | |
54a7a3ed AM |
38 | */ |
39 | ||
40 | #ifndef lint | |
84ee7b23 | 41 | static char *rcsid = "@(#)$Id: cbc.c,v 1.3 1993/12/14 18:01:10 alm Exp $"; |
54a7a3ed AM |
42 | #endif /* not lint */ |
43 | ||
84ee7b23 AM |
44 | #include <sys/types.h> |
45 | #include <ctype.h> | |
54a7a3ed AM |
46 | #include <errno.h> |
47 | #include <pwd.h> | |
54a7a3ed AM |
48 | |
49 | #include "ed.h" | |
50 | ||
84ee7b23 | 51 | |
54a7a3ed AM |
52 | /* |
53 | * Define a divisor for rand() that yields a uniform distribution in the | |
54 | * range 0-255. | |
55 | */ | |
56 | #define RAND_DIV (((unsigned) RAND_MAX + 1) >> 8) | |
57 | ||
58 | /* | |
59 | * BSD and System V systems offer special library calls that do | |
84ee7b23 | 60 | * block move_liness and fills, so if possible we take advantage of them |
54a7a3ed AM |
61 | */ |
62 | #define MEMCPY(dest,src,len) memcpy((dest),(src),(len)) | |
63 | #define MEMZERO(dest,len) memset((dest), 0, (len)) | |
64 | ||
65 | /* Hide the calls to the primitive encryption routines. */ | |
66 | #define DES_KEY(buf) \ | |
67 | if (des_setkey(buf)) \ | |
84ee7b23 | 68 | des_error("des_setkey"); |
54a7a3ed AM |
69 | #define DES_XFORM(buf) \ |
70 | if (des_cipher(buf, buf, 0L, (inverse ? -1 : 1))) \ | |
84ee7b23 | 71 | des_error("des_cipher"); |
54a7a3ed AM |
72 | |
73 | /* | |
74 | * read/write - no error checking | |
75 | */ | |
76 | #define READ(buf, n, fp) fread(buf, sizeof(char), n, fp) | |
77 | #define WRITE(buf, n, fp) fwrite(buf, sizeof(char), n, fp) | |
78 | ||
79 | /* | |
80 | * some things to make references easier | |
81 | */ | |
82 | typedef char Desbuf[8]; | |
83 | #define CHAR(x,i) (x[i]) | |
84 | #define UCHAR(x,i) (x[i]) | |
85 | #define BUFFER(x) (x) | |
86 | #define UBUFFER(x) (x) | |
87 | ||
88 | /* | |
89 | * global variables and related macros | |
90 | */ | |
91 | ||
92 | enum { /* encrypt, decrypt, authenticate */ | |
93 | MODE_ENCRYPT, MODE_DECRYPT, MODE_AUTHENTICATE | |
94 | } mode = MODE_ENCRYPT; | |
95 | ||
96 | Desbuf ivec; /* initialization vector */ | |
97 | Desbuf pvec; /* padding vector */ | |
98 | char bits[] = { /* used to extract bits from a char */ | |
99 | '\200', '\100', '\040', '\020', '\010', '\004', '\002', '\001' | |
100 | }; | |
101 | int pflag; /* 1 to preserve parity bits */ | |
102 | ||
84ee7b23 AM |
103 | unsigned char des_buf[8]; /* shared buffer for get_des_char/put_des_char */ |
104 | int des_ct = 0; /* count for get_des_char/put_des_char */ | |
105 | int des_n = 0; /* index for put_des_char/get_des_char */ | |
54a7a3ed AM |
106 | |
107 | ||
84ee7b23 | 108 | /* init_des_cipher: initialize DES */ |
54a7a3ed | 109 | void |
84ee7b23 | 110 | init_des_cipher() |
54a7a3ed AM |
111 | { |
112 | #ifdef DES | |
113 | int i; | |
114 | ||
115 | des_ct = des_n = 0; | |
116 | ||
117 | /* initialize the initialization vctor */ | |
118 | MEMZERO(ivec, 8); | |
119 | ||
120 | /* intialize the padding vector */ | |
121 | srand((unsigned) time((time_t *) 0)); | |
122 | for (i = 0; i < 8; i++) | |
123 | CHAR(pvec, i) = (char) (rand()/RAND_DIV); | |
124 | #endif | |
125 | } | |
126 | ||
127 | ||
84ee7b23 AM |
128 | /* get_des_char: return next char in an encrypted file */ |
129 | int | |
130 | get_des_char(fp) | |
54a7a3ed AM |
131 | FILE *fp; |
132 | { | |
133 | #ifdef DES | |
134 | if (des_n >= des_ct) { | |
135 | des_n = 0; | |
84ee7b23 | 136 | des_ct = cbc_decode(des_buf, fp); |
54a7a3ed AM |
137 | } |
138 | return (des_ct > 0) ? des_buf[des_n++] : EOF; | |
139 | #endif | |
140 | } | |
141 | ||
142 | ||
84ee7b23 AM |
143 | /* put_des_char: write a char to an encrypted file; return char written */ |
144 | int | |
145 | put_des_char(c, fp) | |
54a7a3ed AM |
146 | int c; |
147 | FILE *fp; | |
148 | { | |
149 | #ifdef DES | |
150 | if (des_n == sizeof des_buf) { | |
84ee7b23 | 151 | des_ct = cbc_encode(des_buf, des_n, fp); |
54a7a3ed AM |
152 | des_n = 0; |
153 | } | |
154 | return (des_ct >= 0) ? (des_buf[des_n++] = c) : EOF; | |
155 | #endif | |
156 | } | |
157 | ||
158 | ||
84ee7b23 AM |
159 | /* flush_des_file: flush an encrypted file's output; return status */ |
160 | int | |
161 | flush_des_file(fp) | |
54a7a3ed AM |
162 | FILE *fp; |
163 | { | |
164 | #ifdef DES | |
165 | if (des_n == sizeof des_buf) { | |
84ee7b23 | 166 | des_ct = cbc_encode(des_buf, des_n, fp); |
54a7a3ed AM |
167 | des_n = 0; |
168 | } | |
84ee7b23 | 169 | return (des_ct >= 0 && cbc_encode(des_buf, des_n, fp) >= 0) ? 0 : EOF; |
54a7a3ed AM |
170 | #endif |
171 | } | |
172 | ||
173 | #ifdef DES | |
174 | /* | |
175 | * get keyword from tty or stdin | |
176 | */ | |
84ee7b23 AM |
177 | int |
178 | get_keyword() | |
54a7a3ed AM |
179 | { |
180 | register char *p; /* used to obtain the key */ | |
181 | Desbuf msgbuf; /* I/O buffer */ | |
182 | ||
183 | /* | |
184 | * get the key | |
185 | */ | |
186 | if (*(p = getpass("Enter key: "))) { | |
187 | ||
188 | /* | |
189 | * copy it, nul-padded, into the key area | |
190 | */ | |
84ee7b23 | 191 | expand_des_key(BUFFER(msgbuf), p); |
54a7a3ed | 192 | MEMZERO(p, _PASSWORD_LEN); |
84ee7b23 | 193 | set_des_key(msgbuf); |
54a7a3ed AM |
194 | MEMZERO(msgbuf, sizeof msgbuf); |
195 | return 1; | |
196 | } | |
197 | return 0; | |
198 | } | |
199 | ||
200 | ||
54a7a3ed AM |
201 | /* |
202 | * print a warning message and, possibly, terminate | |
203 | */ | |
204 | void | |
84ee7b23 | 205 | des_error(s) |
54a7a3ed AM |
206 | char *s; /* the message */ |
207 | { | |
208 | (void)sprintf(errmsg, "%s", s ? s : strerror(errno)); | |
209 | } | |
210 | ||
211 | /* | |
212 | * map a hex character to an integer | |
213 | */ | |
84ee7b23 AM |
214 | int |
215 | hex_to_binary(c, radix) | |
54a7a3ed AM |
216 | int c; /* char to be converted */ |
217 | int radix; /* base (2 to 16) */ | |
218 | { | |
219 | switch(c) { | |
220 | case '0': return(0x0); | |
221 | case '1': return(0x1); | |
222 | case '2': return(radix > 2 ? 0x2 : -1); | |
223 | case '3': return(radix > 3 ? 0x3 : -1); | |
224 | case '4': return(radix > 4 ? 0x4 : -1); | |
225 | case '5': return(radix > 5 ? 0x5 : -1); | |
226 | case '6': return(radix > 6 ? 0x6 : -1); | |
227 | case '7': return(radix > 7 ? 0x7 : -1); | |
228 | case '8': return(radix > 8 ? 0x8 : -1); | |
229 | case '9': return(radix > 9 ? 0x9 : -1); | |
230 | case 'A': case 'a': return(radix > 10 ? 0xa : -1); | |
231 | case 'B': case 'b': return(radix > 11 ? 0xb : -1); | |
232 | case 'C': case 'c': return(radix > 12 ? 0xc : -1); | |
233 | case 'D': case 'd': return(radix > 13 ? 0xd : -1); | |
234 | case 'E': case 'e': return(radix > 14 ? 0xe : -1); | |
235 | case 'F': case 'f': return(radix > 15 ? 0xf : -1); | |
236 | } | |
237 | /* | |
238 | * invalid character | |
239 | */ | |
240 | return(-1); | |
241 | } | |
242 | ||
243 | /* | |
244 | * convert the key to a bit pattern | |
245 | */ | |
246 | void | |
84ee7b23 | 247 | expand_des_key(obuf, ibuf) |
54a7a3ed AM |
248 | char *obuf; /* bit pattern */ |
249 | char *ibuf; /* the key itself */ | |
250 | { | |
251 | register int i, j; /* counter in a for loop */ | |
252 | int nbuf[64]; /* used for hex/key translation */ | |
253 | ||
254 | /* | |
255 | * leading '0x' or '0X' == hex key | |
256 | */ | |
257 | if (ibuf[0] == '0' && (ibuf[1] == 'x' || ibuf[1] == 'X')) { | |
258 | ibuf = &ibuf[2]; | |
259 | /* | |
260 | * now translate it, bombing on any illegal hex digit | |
261 | */ | |
262 | for (i = 0; ibuf[i] && i < 16; i++) | |
84ee7b23 AM |
263 | if ((nbuf[i] = hex_to_binary((int) ibuf[i], 16)) == -1) |
264 | des_error("bad hex digit in key"); | |
54a7a3ed AM |
265 | while (i < 16) |
266 | nbuf[i++] = 0; | |
267 | for (i = 0; i < 8; i++) | |
268 | obuf[i] = | |
269 | ((nbuf[2*i]&0xf)<<4) | (nbuf[2*i+1]&0xf); | |
270 | /* preserve parity bits */ | |
271 | pflag = 1; | |
272 | return; | |
273 | } | |
274 | /* | |
275 | * leading '0b' or '0B' == binary key | |
276 | */ | |
277 | if (ibuf[0] == '0' && (ibuf[1] == 'b' || ibuf[1] == 'B')) { | |
278 | ibuf = &ibuf[2]; | |
279 | /* | |
280 | * now translate it, bombing on any illegal binary digit | |
281 | */ | |
282 | for (i = 0; ibuf[i] && i < 16; i++) | |
84ee7b23 AM |
283 | if ((nbuf[i] = hex_to_binary((int) ibuf[i], 2)) == -1) |
284 | des_error("bad binary digit in key"); | |
54a7a3ed AM |
285 | while (i < 64) |
286 | nbuf[i++] = 0; | |
287 | for (i = 0; i < 8; i++) | |
288 | for (j = 0; j < 8; j++) | |
289 | obuf[i] = (obuf[i]<<1)|nbuf[8*i+j]; | |
290 | /* preserve parity bits */ | |
291 | pflag = 1; | |
292 | return; | |
293 | } | |
294 | /* | |
295 | * no special leader -- ASCII | |
296 | */ | |
297 | (void)strncpy(obuf, ibuf, 8); | |
298 | } | |
299 | ||
300 | /***************** | |
301 | * DES FUNCTIONS * | |
302 | *****************/ | |
303 | /* | |
304 | * This sets the DES key and (if you're using the deszip version) | |
305 | * the direction of the transformation. This uses the Sun | |
306 | * to map the 64-bit key onto the 56 bits that the key schedule | |
307 | * generation routines use: the old way, which just uses the user- | |
308 | * supplied 64 bits as is, and the new way, which resets the parity | |
309 | * bit to be the same as the low-order bit in each character. The | |
310 | * new way generates a greater variety of key schedules, since many | |
311 | * systems set the parity (high) bit of each character to 0, and the | |
312 | * DES ignores the low order bit of each character. | |
313 | */ | |
314 | void | |
84ee7b23 | 315 | set_des_key(buf) |
54a7a3ed AM |
316 | Desbuf buf; /* key block */ |
317 | { | |
318 | register int i, j; /* counter in a for loop */ | |
319 | register int par; /* parity counter */ | |
320 | ||
321 | /* | |
322 | * if the parity is not preserved, flip it | |
323 | */ | |
324 | if (!pflag) { | |
325 | for (i = 0; i < 8; i++) { | |
326 | par = 0; | |
327 | for (j = 1; j < 8; j++) | |
328 | if ((bits[j]&UCHAR(buf, i)) != 0) | |
329 | par++; | |
330 | if ((par&01) == 01) | |
331 | UCHAR(buf, i) = UCHAR(buf, i)&0177; | |
332 | else | |
333 | UCHAR(buf, i) = (UCHAR(buf, i)&0177)|0200; | |
334 | } | |
335 | } | |
336 | ||
337 | DES_KEY(UBUFFER(buf)); | |
338 | } | |
339 | ||
340 | ||
341 | /* | |
342 | * This encrypts using the Cipher Block Chaining mode of DES | |
343 | */ | |
84ee7b23 AM |
344 | int |
345 | cbc_encode(msgbuf, n, fp) | |
54a7a3ed AM |
346 | char *msgbuf; |
347 | int n; | |
348 | FILE *fp; | |
349 | { | |
350 | int inverse = 0; /* 0 to encrypt, 1 to decrypt */ | |
351 | ||
352 | /* | |
353 | * do the transformation | |
354 | */ | |
355 | if (n == 8) { | |
356 | for (n = 0; n < 8; n++) | |
357 | CHAR(msgbuf, n) ^= CHAR(ivec, n); | |
358 | DES_XFORM(UBUFFER(msgbuf)); | |
359 | MEMCPY(BUFFER(ivec), BUFFER(msgbuf), 8); | |
360 | return WRITE(BUFFER(msgbuf), 8, fp); | |
361 | } | |
362 | /* | |
363 | * at EOF or last block -- in either case, the last byte contains | |
364 | * the character representation of the number of bytes in it | |
365 | */ | |
366 | /* | |
367 | MEMZERO(msgbuf + n, 8 - n); | |
368 | */ | |
369 | /* | |
370 | * Pad the last block randomly | |
371 | */ | |
372 | (void)MEMCPY(BUFFER(msgbuf + n), BUFFER(pvec), 8 - n); | |
373 | CHAR(msgbuf, 7) = n; | |
374 | for (n = 0; n < 8; n++) | |
375 | CHAR(msgbuf, n) ^= CHAR(ivec, n); | |
376 | DES_XFORM(UBUFFER(msgbuf)); | |
377 | return WRITE(BUFFER(msgbuf), 8, fp); | |
378 | } | |
379 | ||
380 | /* | |
381 | * This decrypts using the Cipher Block Chaining mode of DES | |
382 | */ | |
84ee7b23 AM |
383 | int |
384 | cbc_decode(msgbuf, fp) | |
54a7a3ed AM |
385 | char *msgbuf; /* I/O buffer */ |
386 | FILE *fp; /* input file descriptor */ | |
387 | { | |
388 | Desbuf ibuf; /* temp buffer for initialization vector */ | |
389 | register int n; /* number of bytes actually read */ | |
390 | register int c; /* used to test for EOF */ | |
391 | int inverse = 1; /* 0 to encrypt, 1 to decrypt */ | |
392 | ||
393 | if ((n = READ(BUFFER(msgbuf), 8, fp)) == 8) { | |
394 | /* | |
395 | * do the transformation | |
396 | */ | |
397 | MEMCPY(BUFFER(ibuf), BUFFER(msgbuf), 8); | |
398 | DES_XFORM(UBUFFER(msgbuf)); | |
399 | for (c = 0; c < 8; c++) | |
400 | UCHAR(msgbuf, c) ^= UCHAR(ivec, c); | |
401 | MEMCPY(BUFFER(ivec), BUFFER(ibuf), 8); | |
402 | /* | |
403 | * if the last one, handle it specially | |
404 | */ | |
405 | if ((c = fgetc(fp)) == EOF) { | |
406 | n = CHAR(msgbuf, 7); | |
407 | if (n < 0 || n > 7) { | |
84ee7b23 | 408 | des_error("decryption failed (block corrupted)"); |
54a7a3ed AM |
409 | return EOF; |
410 | } | |
411 | } else | |
412 | (void)ungetc(c, fp); | |
413 | return n; | |
414 | } | |
415 | if (n > 0) | |
84ee7b23 | 416 | des_error("decryption failed (incomplete block)"); |
54a7a3ed | 417 | else if (n < 0) |
84ee7b23 | 418 | des_error("cannot read file"); |
54a7a3ed AM |
419 | return EOF; |
420 | } | |
421 | #endif /* DES */ |