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Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
Damien Miller95def091999-11-25 00:26:21 +11002 * Author: Tatu Ylonen <ylo@cs.hut.fi>
Damien Miller95def091999-11-25 00:26:21 +11003 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
Damien Miller4af51302000-04-16 11:18:38 +10005 *
Damien Millere4340be2000-09-16 13:29:08 +11006 * 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".
Damien Miller4af51302000-04-16 11:18:38 +100011 *
Damien Millere4340be2000-09-16 13:29:08 +110012 *
13 * Copyright (c) 1999 Niels Provos. All rights reserved.
14 * Copyright (c) 1999,2000 Markus Friedl. All rights reserved.
15 *
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.
24 *
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.
Damien Miller95def091999-11-25 00:26:21 +110035 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100036
37#include "includes.h"
Damien Miller69b69aa2000-10-28 14:19:58 +110038RCSID("$OpenBSD: cipher.c,v 1.37 2000/10/23 19:31:54 markus Exp $");
Damien Millerd4a8b7e1999-10-27 13:42:43 +100039
40#include "ssh.h"
Damien Miller78928792000-04-12 20:17:38 +100041#include "xmalloc.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100042
43#include <openssl/md5.h>
Damien Millerd4a8b7e1999-10-27 13:42:43 +100044
Damien Miller874d77b2000-10-14 16:23:11 +110045
46/* no encryption */
47void
48none_setkey(CipherContext *cc, const u_char *key, u_int keylen)
49{
50}
51void
52none_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
53{
54}
55void
56none_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
57{
58 memcpy(dest, src, len);
59}
60
61/* DES */
62void
63des_ssh1_setkey(CipherContext *cc, const u_char *key, u_int keylen)
64{
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 }
71 des_set_key((void *)key, cc->u.des.key);
72}
73void
74des_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}
78void
79des_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}
84void
85des_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 */
92void
93des3_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}
99void
100des3_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}
108void
109des3_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}
115void
116des3_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
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000123/*
Damien Miller78928792000-04-12 20:17:38 +1000124 * This is used by SSH1:
125 *
126 * What kind of triple DES are these 2 routines?
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000127 *
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 */
137void
Damien Miller874d77b2000-10-14 16:23:11 +1100138des3_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}
147void
148des3_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
149 u_int len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000150{
Damien Miller95def091999-11-25 00:26:21 +1100151 des_cblock iv1;
Damien Miller874d77b2000-10-14 16:23:11 +1100152 des_cblock *iv2 = &cc->u.des3.iv2;
153 des_cblock *iv3 = &cc->u.des3.iv3;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000154
Damien Miller95def091999-11-25 00:26:21 +1100155 memcpy(&iv1, iv2, 8);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000156
Damien Miller874d77b2000-10-14 16:23:11 +1100157 des_cbc_encrypt(src, dest, len, cc->u.des3.key1, &iv1, DES_ENCRYPT);
Damien Miller98c7ad62000-03-09 21:27:49 +1100158 memcpy(&iv1, dest + len - 8, 8);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000159
Damien Miller874d77b2000-10-14 16:23:11 +1100160 des_cbc_encrypt(dest, dest, len, cc->u.des3.key2, iv2, DES_DECRYPT);
Damien Miller95def091999-11-25 00:26:21 +1100161 memcpy(iv2, &iv1, 8); /* Note how iv1 == iv2 on entry and exit. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000162
Damien Miller874d77b2000-10-14 16:23:11 +1100163 des_cbc_encrypt(dest, dest, len, cc->u.des3.key3, iv3, DES_ENCRYPT);
Damien Miller98c7ad62000-03-09 21:27:49 +1100164 memcpy(iv3, dest + len - 8, 8);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000165}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000166void
Damien Miller874d77b2000-10-14 16:23:11 +1100167des3_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
168 u_int len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000169{
Damien Miller95def091999-11-25 00:26:21 +1100170 des_cblock iv1;
Damien Miller874d77b2000-10-14 16:23:11 +1100171 des_cblock *iv2 = &cc->u.des3.iv2;
172 des_cblock *iv3 = &cc->u.des3.iv3;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000173
Damien Miller95def091999-11-25 00:26:21 +1100174 memcpy(&iv1, iv2, 8);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000175
Damien Miller874d77b2000-10-14 16:23:11 +1100176 des_cbc_encrypt(src, dest, len, cc->u.des3.key3, iv3, DES_DECRYPT);
Damien Miller98c7ad62000-03-09 21:27:49 +1100177 memcpy(iv3, src + len - 8, 8);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000178
Damien Miller874d77b2000-10-14 16:23:11 +1100179 des_cbc_encrypt(dest, dest, len, cc->u.des3.key2, iv2, DES_ENCRYPT);
Damien Miller98c7ad62000-03-09 21:27:49 +1100180 memcpy(iv2, dest + len - 8, 8);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000181
Damien Miller874d77b2000-10-14 16:23:11 +1100182 des_cbc_encrypt(dest, dest, len, cc->u.des3.key1, &iv1, DES_DECRYPT);
Damien Miller95def091999-11-25 00:26:21 +1100183 /* memcpy(&iv1, iv2, 8); */
184 /* Note how iv1 == iv2 on entry and exit. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000185}
186
Damien Miller874d77b2000-10-14 16:23:11 +1100187/* Blowfish */
188void
189blowfish_setkey(CipherContext *cc, const u_char *key, u_int keylen)
190{
191 BF_set_key(&cc->u.bf.key, keylen, (unsigned char *)key);
192}
193void
194blowfish_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}
201void
202blowfish_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}
208void
209blowfish_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
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000216/*
Damien Miller78928792000-04-12 20:17:38 +1000217 * SSH1 uses a variation on Blowfish, all bytes must be swapped before
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000218 * and after encryption/decryption. Thus the swap_bytes stuff (yuk).
219 */
Damien Miller95def091999-11-25 00:26:21 +1100220static void
Damien Miller69b69aa2000-10-28 14:19:58 +1100221swap_bytes(const unsigned char *src, unsigned char *dst, int n)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000222{
Damien Miller69b69aa2000-10-28 14:19:58 +1100223 char c[4];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000224
Damien Miller69b69aa2000-10-28 14:19:58 +1100225 /* 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++;
Damien Miller95def091999-11-25 00:26:21 +1100231
Damien Miller69b69aa2000-10-28 14:19:58 +1100232 *dst++ = c[0];
233 *dst++ = c[1];
234 *dst++ = c[2];
235 *dst++ = c[3];
Damien Miller95def091999-11-25 00:26:21 +1100236 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000237}
238
Damien Miller874d77b2000-10-14 16:23:11 +1100239void
240blowfish_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
241 u_int len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000242{
Damien Miller874d77b2000-10-14 16:23:11 +1100243 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}
248void
249blowfish_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
250 u_int len)
251{
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}
257
258/* alleged rc4 */
259void
260arcfour_setkey(CipherContext *cc, const u_char *key, u_int keylen)
261{
262 RC4_set_key(&cc->u.rc4, keylen, (u_char *)key);
263}
264void
265arcfour_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}
269
270/* CAST */
271void
272cast_setkey(CipherContext *cc, const u_char *key, u_int keylen)
273{
274 CAST_set_key(&cc->u.cast.key, keylen, (unsigned char *) key);
275}
276void
277cast_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
278{
279 if (iv == NULL)
280 fatal("no IV for %s.", cc->cipher->name);
281 memcpy(cc->u.cast.iv, (char *)iv, 8);
282}
283void
284cast_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
285{
286 CAST_cbc_encrypt(src, dest, len, &cc->u.cast.key, cc->u.cast.iv,
287 CAST_ENCRYPT);
288}
289void
290cast_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
291{
292 CAST_cbc_encrypt(src, dest, len, &cc->u.cast.key, cc->u.cast.iv,
293 CAST_DECRYPT);
294}
295
296/* RIJNDAEL */
297
298#define RIJNDAEL_BLOCKSIZE 16
299void
300rijndael_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}
305void
306rijndael_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}
312void
313rijndael_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
339void
340rijndael_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}
365
366Cipher ciphers[] = {
367 { "none",
368 SSH_CIPHER_NONE, 8, 0,
369 none_setkey, none_setiv,
370 none_crypt, none_crypt },
371 { "des",
372 SSH_CIPHER_DES, 8, 8,
373 des_ssh1_setkey, des_ssh1_setiv,
374 des_ssh1_encrypt, des_ssh1_decrypt },
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 },
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 },
428 { NULL, SSH_CIPHER_ILLEGAL, 0, 0, NULL, NULL, NULL, NULL }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000429};
430
Damien Miller874d77b2000-10-14 16:23:11 +1100431/*--*/
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000432
Damien Miller4af51302000-04-16 11:18:38 +1000433unsigned int
Damien Miller874d77b2000-10-14 16:23:11 +1100434cipher_mask_ssh1(int client)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000435{
Damien Miller95def091999-11-25 00:26:21 +1100436 unsigned int mask = 0;
Damien Miller874d77b2000-10-14 16:23:11 +1100437 mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */
Damien Miller95def091999-11-25 00:26:21 +1100438 mask |= 1 << SSH_CIPHER_BLOWFISH;
Damien Miller874d77b2000-10-14 16:23:11 +1100439 if (client) {
440 mask |= 1 << SSH_CIPHER_DES;
441 }
Damien Miller1383bd82000-04-06 12:32:37 +1000442 return mask;
443}
Damien Miller874d77b2000-10-14 16:23:11 +1100444
445Cipher *
446cipher_by_name(const char *name)
Damien Miller1383bd82000-04-06 12:32:37 +1000447{
Damien Miller874d77b2000-10-14 16:23:11 +1100448 Cipher *c;
449 for (c = ciphers; c->name != NULL; c++)
450 if (strcasecmp(c->name, name) == 0)
451 return c;
452 return NULL;
Damien Miller1383bd82000-04-06 12:32:37 +1000453}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000454
Damien Miller874d77b2000-10-14 16:23:11 +1100455Cipher *
456cipher_by_number(int id)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000457{
Damien Miller874d77b2000-10-14 16:23:11 +1100458 Cipher *c;
459 for (c = ciphers; c->name != NULL; c++)
460 if (c->number == id)
461 return c;
462 return NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000463}
464
Damien Miller78928792000-04-12 20:17:38 +1000465#define CIPHER_SEP ","
466int
467ciphers_valid(const char *names)
468{
Damien Miller874d77b2000-10-14 16:23:11 +1100469 Cipher *c;
Damien Miller37023962000-07-11 17:31:38 +1000470 char *ciphers, *cp;
Damien Miller78928792000-04-12 20:17:38 +1000471 char *p;
Damien Miller78928792000-04-12 20:17:38 +1000472
Damien Millerb1715dc2000-05-30 13:44:51 +1000473 if (names == NULL || strcmp(names, "") == 0)
Damien Miller78928792000-04-12 20:17:38 +1000474 return 0;
Damien Miller37023962000-07-11 17:31:38 +1000475 ciphers = cp = xstrdup(names);
Damien Miller874d77b2000-10-14 16:23:11 +1100476 for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
Damien Miller37023962000-07-11 17:31:38 +1000477 (p = strsep(&cp, CIPHER_SEP))) {
Damien Miller874d77b2000-10-14 16:23:11 +1100478 c = cipher_by_name(p);
479 if (c == NULL || c->number != SSH_CIPHER_SSH2) {
480 debug("bad cipher %s [%s]", p, names);
Damien Miller78928792000-04-12 20:17:38 +1000481 xfree(ciphers);
482 return 0;
Damien Miller874d77b2000-10-14 16:23:11 +1100483 } else {
Damien Miller50a41ed2000-10-16 12:14:42 +1100484 debug3("cipher ok: %s [%s]", p, names);
Damien Miller78928792000-04-12 20:17:38 +1000485 }
486 }
Damien Miller50a41ed2000-10-16 12:14:42 +1100487 debug3("ciphers ok: [%s]", names);
Damien Miller78928792000-04-12 20:17:38 +1000488 xfree(ciphers);
489 return 1;
490}
491
Damien Miller5428f641999-11-25 11:54:57 +1100492/*
493 * Parses the name of the cipher. Returns the number of the corresponding
494 * cipher, or -1 on error.
495 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000496
497int
498cipher_number(const char *name)
499{
Damien Miller874d77b2000-10-14 16:23:11 +1100500 Cipher *c;
Damien Millerb1715dc2000-05-30 13:44:51 +1000501 if (name == NULL)
502 return -1;
Damien Miller874d77b2000-10-14 16:23:11 +1100503 c = cipher_by_name(name);
504 return (c==NULL) ? -1 : c->number;
505}
506
507char *
508cipher_name(int id)
509{
510 Cipher *c = cipher_by_number(id);
511 return (c==NULL) ? "<unknown>" : c->name;
512}
513
514void
515cipher_init(CipherContext *cc, Cipher *cipher,
516 const u_char *key, u_int keylen, const u_char *iv, u_int ivlen)
517{
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);
527}
528
529void
530cipher_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);
535}
536
537void
538cipher_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
539{
540 if (len % cc->cipher->block_size)
541 fatal("cipher_decrypt: bad ciphertext length %d", len);
542 cc->cipher->decrypt(cc, dest, src, len);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000543}
544
Damien Miller5428f641999-11-25 11:54:57 +1100545/*
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 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000549
Damien Miller4af51302000-04-16 11:18:38 +1000550void
Damien Miller874d77b2000-10-14 16:23:11 +1100551cipher_set_key_string(CipherContext *cc, Cipher *cipher,
552 const char *passphrase)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000553{
Damien Miller95def091999-11-25 00:26:21 +1100554 MD5_CTX md;
555 unsigned char digest[16];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000556
Damien Miller95def091999-11-25 00:26:21 +1100557 MD5_Init(&md);
Damien Miller874d77b2000-10-14 16:23:11 +1100558 MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase));
Damien Miller95def091999-11-25 00:26:21 +1100559 MD5_Final(digest, &md);
560
Damien Miller874d77b2000-10-14 16:23:11 +1100561 cipher_init(cc, cipher, digest, 16, NULL, 0);
Damien Miller95def091999-11-25 00:26:21 +1100562
563 memset(digest, 0, sizeof(digest));
564 memset(&md, 0, sizeof(md));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000565}