Annotation of src/usr.bin/ssh/cipher.c, Revision 1.37
1.1 deraadt 1: /*
1.30 deraadt 2: * Author: Tatu Ylonen <ylo@cs.hut.fi>
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
1.26 markus 5: *
1.30 deraadt 6: * As far as I am concerned, the code I have written for this software
7: * can be used freely for any purpose. Any derived versions of this
8: * software must be clearly marked as such, and if the derived work is
9: * incompatible with the protocol description in the RFC file, it must be
10: * called by a name other than "ssh" or "Secure Shell".
1.26 markus 11: *
12: *
1.30 deraadt 13: * Copyright (c) 1999 Niels Provos. All rights reserved.
14: * Copyright (c) 1999,2000 Markus Friedl. All rights reserved.
1.26 markus 15: *
1.30 deraadt 16: * Redistribution and use in source and binary forms, with or without
17: * modification, are permitted provided that the following conditions
18: * are met:
19: * 1. Redistributions of source code must retain the above copyright
20: * notice, this list of conditions and the following disclaimer.
21: * 2. Redistributions in binary form must reproduce the above copyright
22: * notice, this list of conditions and the following disclaimer in the
23: * documentation and/or other materials provided with the distribution.
1.26 markus 24: *
1.30 deraadt 25: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
26: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
29: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
30: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.17 deraadt 35: */
1.1 deraadt 36:
37: #include "includes.h"
1.37 ! markus 38: RCSID("$OpenBSD: cipher.c,v 1.36 2000/10/14 10:01:15 markus Exp $");
1.1 deraadt 39:
40: #include "ssh.h"
1.24 markus 41: #include "xmalloc.h"
1.8 deraadt 42:
1.25 markus 43: #include <openssl/md5.h>
1.1 deraadt 44:
1.32 markus 45:
46: /* no encryption */
47: void
48: none_setkey(CipherContext *cc, const u_char *key, u_int keylen)
49: {
50: }
51: void
52: none_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
53: {
54: }
55: void
56: none_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
57: {
58: memcpy(dest, src, len);
59: }
60:
61: /* DES */
62: void
63: des_ssh1_setkey(CipherContext *cc, const u_char *key, u_int keylen)
64: {
1.34 markus 65: static int dowarn = 1;
66: if (dowarn) {
67: error("Warning: use of DES is strongly discouraged "
68: "due to cryptographic weaknesses");
69: dowarn = 0;
70: }
1.32 markus 71: des_set_key((void *)key, cc->u.des.key);
72: }
73: void
74: des_ssh1_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
75: {
76: memset(cc->u.des.iv, 0, sizeof(cc->u.des.iv));
77: }
78: void
79: des_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
80: {
81: des_ncbc_encrypt(src, dest, len, cc->u.des.key, &cc->u.des.iv,
82: DES_ENCRYPT);
83: }
84: void
85: des_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
86: {
87: des_ncbc_encrypt(src, dest, len, cc->u.des.key, &cc->u.des.iv,
88: DES_DECRYPT);
89: }
90:
91: /* 3DES */
92: void
93: des3_setkey(CipherContext *cc, const u_char *key, u_int keylen)
94: {
95: des_set_key((void *) key, cc->u.des3.key1);
96: des_set_key((void *) (key+8), cc->u.des3.key2);
97: des_set_key((void *) (key+16), cc->u.des3.key3);
98: }
99: void
100: des3_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
101: {
102: memset(cc->u.des3.iv2, 0, sizeof(cc->u.des3.iv2));
103: memset(cc->u.des3.iv3, 0, sizeof(cc->u.des3.iv3));
104: if (iv == NULL)
105: return;
106: memcpy(cc->u.des3.iv3, (char *)iv, 8);
107: }
108: void
109: des3_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
110: {
111: des_ede3_cbc_encrypt(src, dest, len,
112: cc->u.des3.key1, cc->u.des3.key2, cc->u.des3.key3,
113: &cc->u.des3.iv3, DES_ENCRYPT);
114: }
115: void
116: des3_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
117: {
118: des_ede3_cbc_encrypt(src, dest, len,
119: cc->u.des3.key1, cc->u.des3.key2, cc->u.des3.key3,
120: &cc->u.des3.iv3, DES_DECRYPT);
121: }
122:
1.1 deraadt 123: /*
1.24 markus 124: * This is used by SSH1:
125: *
1.23 deraadt 126: * What kind of triple DES are these 2 routines?
1.1 deraadt 127: *
128: * Why is there a redundant initialization vector?
129: *
130: * If only iv3 was used, then, this would till effect have been
131: * outer-cbc. However, there is also a private iv1 == iv2 which
132: * perhaps makes differential analysis easier. On the other hand, the
133: * private iv1 probably makes the CRC-32 attack ineffective. This is a
134: * result of that there is no longer any known iv1 to use when
135: * choosing the X block.
136: */
137: void
1.32 markus 138: des3_ssh1_setkey(CipherContext *cc, const u_char *key, u_int keylen)
139: {
140: des_set_key((void *) key, cc->u.des3.key1);
141: des_set_key((void *) (key+8), cc->u.des3.key2);
142: if (keylen <= 16)
143: des_set_key((void *) key, cc->u.des3.key3);
144: else
145: des_set_key((void *) (key+16), cc->u.des3.key3);
146: }
147: void
148: des3_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
149: u_int len)
1.1 deraadt 150: {
1.16 markus 151: des_cblock iv1;
1.32 markus 152: des_cblock *iv2 = &cc->u.des3.iv2;
153: des_cblock *iv3 = &cc->u.des3.iv3;
1.1 deraadt 154:
1.16 markus 155: memcpy(&iv1, iv2, 8);
1.1 deraadt 156:
1.32 markus 157: des_cbc_encrypt(src, dest, len, cc->u.des3.key1, &iv1, DES_ENCRYPT);
1.16 markus 158: memcpy(&iv1, dest + len - 8, 8);
1.1 deraadt 159:
1.32 markus 160: des_cbc_encrypt(dest, dest, len, cc->u.des3.key2, iv2, DES_DECRYPT);
1.16 markus 161: memcpy(iv2, &iv1, 8); /* Note how iv1 == iv2 on entry and exit. */
1.1 deraadt 162:
1.32 markus 163: des_cbc_encrypt(dest, dest, len, cc->u.des3.key3, iv3, DES_ENCRYPT);
1.16 markus 164: memcpy(iv3, dest + len - 8, 8);
1.1 deraadt 165: }
166: void
1.32 markus 167: des3_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
168: u_int len)
1.1 deraadt 169: {
1.16 markus 170: des_cblock iv1;
1.32 markus 171: des_cblock *iv2 = &cc->u.des3.iv2;
172: des_cblock *iv3 = &cc->u.des3.iv3;
1.1 deraadt 173:
1.16 markus 174: memcpy(&iv1, iv2, 8);
1.1 deraadt 175:
1.32 markus 176: des_cbc_encrypt(src, dest, len, cc->u.des3.key3, iv3, DES_DECRYPT);
1.16 markus 177: memcpy(iv3, src + len - 8, 8);
1.1 deraadt 178:
1.32 markus 179: des_cbc_encrypt(dest, dest, len, cc->u.des3.key2, iv2, DES_ENCRYPT);
1.16 markus 180: memcpy(iv2, dest + len - 8, 8);
1.1 deraadt 181:
1.32 markus 182: des_cbc_encrypt(dest, dest, len, cc->u.des3.key1, &iv1, DES_DECRYPT);
1.16 markus 183: /* memcpy(&iv1, iv2, 8); */
184: /* Note how iv1 == iv2 on entry and exit. */
1.1 deraadt 185: }
186:
1.32 markus 187: /* Blowfish */
188: void
189: blowfish_setkey(CipherContext *cc, const u_char *key, u_int keylen)
190: {
191: BF_set_key(&cc->u.bf.key, keylen, (unsigned char *)key);
192: }
193: void
194: blowfish_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
195: {
196: if (iv == NULL)
197: memset(cc->u.bf.iv, 0, 8);
198: else
199: memcpy(cc->u.bf.iv, (char *)iv, 8);
200: }
201: void
202: blowfish_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
203: u_int len)
204: {
205: BF_cbc_encrypt((void *)src, dest, len, &cc->u.bf.key, cc->u.bf.iv,
206: BF_ENCRYPT);
207: }
208: void
209: blowfish_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
210: u_int len)
211: {
212: BF_cbc_encrypt((void *)src, dest, len, &cc->u.bf.key, cc->u.bf.iv,
213: BF_DECRYPT);
214: }
215:
1.1 deraadt 216: /*
1.24 markus 217: * SSH1 uses a variation on Blowfish, all bytes must be swapped before
1.1 deraadt 218: * and after encryption/decryption. Thus the swap_bytes stuff (yuk).
219: */
1.16 markus 220: static void
1.37 ! markus 221: swap_bytes(const unsigned char *src, unsigned char *dst, int n)
1.1 deraadt 222: {
1.37 ! markus 223: char c[4];
! 224:
! 225: /* Process 4 bytes every lap. */
! 226: for (n = n / 4; n > 0; n--) {
! 227: c[3] = *src++;
! 228: c[2] = *src++;
! 229: c[1] = *src++;
! 230: c[0] = *src++;
! 231:
! 232: *dst++ = c[0];
! 233: *dst++ = c[1];
! 234: *dst++ = c[2];
! 235: *dst++ = c[3];
1.16 markus 236: }
1.1 deraadt 237: }
238:
1.32 markus 239: void
240: blowfish_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
241: u_int len)
242: {
243: swap_bytes(src, dest, len);
244: BF_cbc_encrypt((void *)dest, dest, len, &cc->u.bf.key, cc->u.bf.iv,
245: BF_ENCRYPT);
246: swap_bytes(dest, dest, len);
247: }
248: void
249: blowfish_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
250: u_int len)
1.4 provos 251: {
1.32 markus 252: swap_bytes(src, dest, len);
253: BF_cbc_encrypt((void *)dest, dest, len, &cc->u.bf.key, cc->u.bf.iv,
254: BF_DECRYPT);
255: swap_bytes(dest, dest, len);
256: }
1.1 deraadt 257:
1.32 markus 258: /* alleged rc4 */
259: void
260: arcfour_setkey(CipherContext *cc, const u_char *key, u_int keylen)
261: {
262: RC4_set_key(&cc->u.rc4, keylen, (u_char *)key);
263: }
264: void
265: arcfour_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
266: {
267: RC4(&cc->u.rc4, len, (u_char *)src, dest);
268: }
1.1 deraadt 269:
1.32 markus 270: /* CAST */
271: void
272: cast_setkey(CipherContext *cc, const u_char *key, u_int keylen)
273: {
274: CAST_set_key(&cc->u.cast.key, keylen, (unsigned char *) key);
275: }
276: void
277: cast_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
1.1 deraadt 278: {
1.32 markus 279: if (iv == NULL)
280: fatal("no IV for %s.", cc->cipher->name);
281: memcpy(cc->u.cast.iv, (char *)iv, 8);
1.22 markus 282: }
1.32 markus 283: void
284: cast_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
1.22 markus 285: {
1.32 markus 286: CAST_cbc_encrypt(src, dest, len, &cc->u.cast.key, cc->u.cast.iv,
287: CAST_ENCRYPT);
1.1 deraadt 288: }
1.32 markus 289: void
290: cast_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
1.22 markus 291: {
1.32 markus 292: CAST_cbc_encrypt(src, dest, len, &cc->u.cast.key, cc->u.cast.iv,
293: CAST_DECRYPT);
1.22 markus 294: }
1.1 deraadt 295:
1.35 markus 296: /* RIJNDAEL */
297:
298: #define RIJNDAEL_BLOCKSIZE 16
299: void
300: rijndael_setkey(CipherContext *cc, const u_char *key, u_int keylen)
301: {
302: rijndael_set_key(&cc->u.rijndael.enc, (u4byte *)key, 8*keylen, 1);
303: rijndael_set_key(&cc->u.rijndael.dec, (u4byte *)key, 8*keylen, 0);
304: }
305: void
306: rijndael_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
307: {
308: if (iv == NULL)
309: fatal("no IV for %s.", cc->cipher->name);
310: memcpy((u_char *)cc->u.rijndael.iv, iv, RIJNDAEL_BLOCKSIZE);
311: }
312: void
313: rijndael_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
314: u_int len)
315: {
316: rijndael_ctx *ctx = &cc->u.rijndael.enc;
317: u4byte *iv = cc->u.rijndael.iv;
318: u4byte in[4];
319: u4byte *cprev, *cnow, *plain;
320: int i, blocks = len / RIJNDAEL_BLOCKSIZE;
321: if (len == 0)
322: return;
323: if (len % RIJNDAEL_BLOCKSIZE)
324: fatal("rijndael_cbc_encrypt: bad len %d", len);
325: cnow = (u4byte*) dest;
326: plain = (u4byte*) src;
327: cprev = iv;
328: for(i = 0; i < blocks; i++, plain+=4, cnow+=4) {
329: in[0] = plain[0] ^ cprev[0];
330: in[1] = plain[1] ^ cprev[1];
331: in[2] = plain[2] ^ cprev[2];
332: in[3] = plain[3] ^ cprev[3];
333: rijndael_encrypt(ctx, in, cnow);
334: cprev = cnow;
335: }
336: memcpy(iv, cprev, RIJNDAEL_BLOCKSIZE);
337: }
338:
339: void
340: rijndael_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
341: u_int len)
342: {
343: rijndael_ctx *ctx = &cc->u.rijndael.dec;
344: u4byte *iv = cc->u.rijndael.iv;
345: u4byte ivsaved[4];
346: u4byte *cnow = (u4byte*) (src+len-RIJNDAEL_BLOCKSIZE);
347: u4byte *plain = (u4byte*) (dest+len-RIJNDAEL_BLOCKSIZE);
348: u4byte *ivp;
349: int i, blocks = len / RIJNDAEL_BLOCKSIZE;
350: if (len == 0)
351: return;
352: if (len % RIJNDAEL_BLOCKSIZE)
353: fatal("rijndael_cbc_decrypt: bad len %d", len);
354: memcpy(ivsaved, cnow, RIJNDAEL_BLOCKSIZE);
355: for(i = blocks; i > 0; i--, cnow-=4, plain-=4) {
356: rijndael_decrypt(ctx, cnow, plain);
357: ivp = (i == 1) ? iv : cnow-4;
358: plain[0] ^= ivp[0];
359: plain[1] ^= ivp[1];
360: plain[2] ^= ivp[2];
361: plain[3] ^= ivp[3];
362: }
363: memcpy(iv, ivsaved, RIJNDAEL_BLOCKSIZE);
364: }
1.32 markus 365:
366: Cipher ciphers[] = {
367: { "none",
368: SSH_CIPHER_NONE, 8, 0,
369: none_setkey, none_setiv,
370: none_crypt, none_crypt },
1.34 markus 371: { "des",
372: SSH_CIPHER_DES, 8, 8,
373: des_ssh1_setkey, des_ssh1_setiv,
374: des_ssh1_encrypt, des_ssh1_decrypt },
1.32 markus 375: { "3des",
376: SSH_CIPHER_3DES, 8, 16,
377: des3_ssh1_setkey, des3_setiv,
378: des3_ssh1_encrypt, des3_ssh1_decrypt },
379: { "blowfish",
380: SSH_CIPHER_BLOWFISH, 8, 16,
381: blowfish_setkey, blowfish_setiv,
382: blowfish_ssh1_encrypt, blowfish_ssh1_decrypt },
383:
384: { "3des-cbc",
385: SSH_CIPHER_SSH2, 8, 24,
386: des3_setkey, des3_setiv,
387: des3_cbc_encrypt, des3_cbc_decrypt },
388: { "blowfish-cbc",
389: SSH_CIPHER_SSH2, 8, 16,
390: blowfish_setkey, blowfish_setiv,
391: blowfish_cbc_encrypt, blowfish_cbc_decrypt },
392: { "cast128-cbc",
393: SSH_CIPHER_SSH2, 8, 16,
394: cast_setkey, cast_setiv,
395: cast_cbc_encrypt, cast_cbc_decrypt },
396: { "arcfour",
397: SSH_CIPHER_SSH2, 8, 16,
398: arcfour_setkey, none_setiv,
399: arcfour_crypt, arcfour_crypt },
1.35 markus 400: { "aes128-cbc",
401: SSH_CIPHER_SSH2, 16, 16,
402: rijndael_setkey, rijndael_setiv,
403: rijndael_cbc_encrypt, rijndael_cbc_decrypt },
404: { "aes192-cbc",
405: SSH_CIPHER_SSH2, 16, 24,
406: rijndael_setkey, rijndael_setiv,
407: rijndael_cbc_encrypt, rijndael_cbc_decrypt },
408: { "aes256-cbc",
409: SSH_CIPHER_SSH2, 16, 32,
410: rijndael_setkey, rijndael_setiv,
411: rijndael_cbc_encrypt, rijndael_cbc_decrypt },
412: { "rijndael128-cbc",
413: SSH_CIPHER_SSH2, 16, 16,
414: rijndael_setkey, rijndael_setiv,
415: rijndael_cbc_encrypt, rijndael_cbc_decrypt },
416: { "rijndael192-cbc",
417: SSH_CIPHER_SSH2, 16, 24,
418: rijndael_setkey, rijndael_setiv,
419: rijndael_cbc_encrypt, rijndael_cbc_decrypt },
420: { "rijndael256-cbc",
421: SSH_CIPHER_SSH2, 16, 32,
422: rijndael_setkey, rijndael_setiv,
423: rijndael_cbc_encrypt, rijndael_cbc_decrypt },
424: { "rijndael-cbc@lysator.liu.se",
425: SSH_CIPHER_SSH2, 16, 32,
426: rijndael_setkey, rijndael_setiv,
427: rijndael_cbc_encrypt, rijndael_cbc_decrypt },
1.32 markus 428: { NULL, SSH_CIPHER_ILLEGAL, 0, 0, NULL, NULL, NULL, NULL }
429: };
430:
431: /*--*/
1.1 deraadt 432:
1.32 markus 433: unsigned int
1.34 markus 434: cipher_mask_ssh1(int client)
1.1 deraadt 435: {
1.32 markus 436: unsigned int mask = 0;
1.34 markus 437: mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */
438: mask |= 1 << SSH_CIPHER_BLOWFISH;
439: if (client) {
440: mask |= 1 << SSH_CIPHER_DES;
1.32 markus 441: }
442: return mask;
1.1 deraadt 443: }
444:
1.32 markus 445: Cipher *
446: cipher_by_name(const char *name)
447: {
448: Cipher *c;
449: for (c = ciphers; c->name != NULL; c++)
450: if (strcasecmp(c->name, name) == 0)
451: return c;
452: return NULL;
453: }
454:
455: Cipher *
456: cipher_by_number(int id)
457: {
458: Cipher *c;
459: for (c = ciphers; c->name != NULL; c++)
460: if (c->number == id)
461: return c;
462: return NULL;
463: }
1.24 markus 464:
465: #define CIPHER_SEP ","
466: int
467: ciphers_valid(const char *names)
468: {
1.32 markus 469: Cipher *c;
1.29 ho 470: char *ciphers, *cp;
1.24 markus 471: char *p;
472:
1.27 markus 473: if (names == NULL || strcmp(names, "") == 0)
1.24 markus 474: return 0;
1.29 ho 475: ciphers = cp = xstrdup(names);
1.32 markus 476: for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
1.29 ho 477: (p = strsep(&cp, CIPHER_SEP))) {
1.32 markus 478: c = cipher_by_name(p);
479: if (c == NULL || c->number != SSH_CIPHER_SSH2) {
480: debug("bad cipher %s [%s]", p, names);
1.24 markus 481: xfree(ciphers);
482: return 0;
1.32 markus 483: } else {
1.36 markus 484: debug3("cipher ok: %s [%s]", p, names);
1.24 markus 485: }
486: }
1.36 markus 487: debug3("ciphers ok: [%s]", names);
1.24 markus 488: xfree(ciphers);
489: return 1;
490: }
491:
1.18 markus 492: /*
493: * Parses the name of the cipher. Returns the number of the corresponding
494: * cipher, or -1 on error.
495: */
1.1 deraadt 496:
1.4 provos 497: int
498: cipher_number(const char *name)
1.1 deraadt 499: {
1.32 markus 500: Cipher *c;
1.27 markus 501: if (name == NULL)
502: return -1;
1.32 markus 503: c = cipher_by_name(name);
504: return (c==NULL) ? -1 : c->number;
1.1 deraadt 505: }
506:
1.32 markus 507: char *
508: cipher_name(int id)
1.1 deraadt 509: {
1.32 markus 510: Cipher *c = cipher_by_number(id);
511: return (c==NULL) ? "<unknown>" : c->name;
1.1 deraadt 512: }
513:
1.26 markus 514: void
1.32 markus 515: cipher_init(CipherContext *cc, Cipher *cipher,
516: const u_char *key, u_int keylen, const u_char *iv, u_int ivlen)
1.16 markus 517: {
1.32 markus 518: if (keylen < cipher->key_len)
519: fatal("cipher_init: key length %d is insufficient for %s.",
520: keylen, cipher->name);
521: if (iv != NULL && ivlen < cipher->block_size)
522: fatal("cipher_init: iv length %d is insufficient for %s.",
523: ivlen, cipher->name);
524: cc->cipher = cipher;
525: cipher->setkey(cc, key, keylen);
526: cipher->setiv(cc, iv, ivlen);
1.1 deraadt 527: }
1.21 markus 528:
1.26 markus 529: void
1.32 markus 530: cipher_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
531: {
532: if (len % cc->cipher->block_size)
533: fatal("cipher_encrypt: bad plaintext length %d", len);
534: cc->cipher->encrypt(cc, dest, src, len);
1.21 markus 535: }
536:
1.26 markus 537: void
1.32 markus 538: cipher_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
1.16 markus 539: {
1.32 markus 540: if (len % cc->cipher->block_size)
541: fatal("cipher_decrypt: bad ciphertext length %d", len);
542: cc->cipher->decrypt(cc, dest, src, len);
1.16 markus 543: }
1.1 deraadt 544:
1.32 markus 545: /*
546: * Selects the cipher, and keys if by computing the MD5 checksum of the
547: * passphrase and using the resulting 16 bytes as the key.
548: */
1.1 deraadt 549:
1.26 markus 550: void
1.32 markus 551: cipher_set_key_string(CipherContext *cc, Cipher *cipher,
552: const char *passphrase)
1.16 markus 553: {
1.32 markus 554: MD5_CTX md;
555: unsigned char digest[16];
556:
557: MD5_Init(&md);
558: MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase));
559: MD5_Final(digest, &md);
1.16 markus 560:
1.32 markus 561: cipher_init(cc, cipher, digest, 16, NULL, 0);
1.16 markus 562:
1.32 markus 563: memset(digest, 0, sizeof(digest));
564: memset(&md, 0, sizeof(md));
1.1 deraadt 565: }