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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 Millere4340be2000-09-16 13:29:08 +110038RCSID("$OpenBSD: cipher.c,v 1.31 2000/09/12 00:38:32 deraadt Exp $");
Damien Millerd4a8b7e1999-10-27 13:42:43 +100039
40#include "ssh.h"
41#include "cipher.h"
Damien Miller78928792000-04-12 20:17:38 +100042#include "xmalloc.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100043
44#include <openssl/md5.h>
Damien Millerd4a8b7e1999-10-27 13:42:43 +100045
46/*
Damien Miller78928792000-04-12 20:17:38 +100047 * This is used by SSH1:
48 *
49 * What kind of triple DES are these 2 routines?
Damien Millerd4a8b7e1999-10-27 13:42:43 +100050 *
51 * Why is there a redundant initialization vector?
52 *
53 * If only iv3 was used, then, this would till effect have been
54 * outer-cbc. However, there is also a private iv1 == iv2 which
55 * perhaps makes differential analysis easier. On the other hand, the
56 * private iv1 probably makes the CRC-32 attack ineffective. This is a
57 * result of that there is no longer any known iv1 to use when
58 * choosing the X block.
59 */
60void
61SSH_3CBC_ENCRYPT(des_key_schedule ks1,
Damien Miller95def091999-11-25 00:26:21 +110062 des_key_schedule ks2, des_cblock * iv2,
63 des_key_schedule ks3, des_cblock * iv3,
Damien Miller98c7ad62000-03-09 21:27:49 +110064 unsigned char *dest, unsigned char *src,
Damien Millerd4a8b7e1999-10-27 13:42:43 +100065 unsigned int len)
66{
Damien Miller95def091999-11-25 00:26:21 +110067 des_cblock iv1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100068
Damien Miller95def091999-11-25 00:26:21 +110069 memcpy(&iv1, iv2, 8);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100070
Damien Miller95def091999-11-25 00:26:21 +110071 des_cbc_encrypt(src, dest, len, ks1, &iv1, DES_ENCRYPT);
Damien Miller98c7ad62000-03-09 21:27:49 +110072 memcpy(&iv1, dest + len - 8, 8);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100073
Damien Miller95def091999-11-25 00:26:21 +110074 des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_DECRYPT);
75 memcpy(iv2, &iv1, 8); /* Note how iv1 == iv2 on entry and exit. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100076
Damien Miller95def091999-11-25 00:26:21 +110077 des_cbc_encrypt(dest, dest, len, ks3, iv3, DES_ENCRYPT);
Damien Miller98c7ad62000-03-09 21:27:49 +110078 memcpy(iv3, dest + len - 8, 8);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100079}
80
81void
82SSH_3CBC_DECRYPT(des_key_schedule ks1,
Damien Miller95def091999-11-25 00:26:21 +110083 des_key_schedule ks2, des_cblock * iv2,
84 des_key_schedule ks3, des_cblock * iv3,
Damien Miller98c7ad62000-03-09 21:27:49 +110085 unsigned char *dest, unsigned char *src,
Damien Millerd4a8b7e1999-10-27 13:42:43 +100086 unsigned int len)
87{
Damien Miller95def091999-11-25 00:26:21 +110088 des_cblock iv1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100089
Damien Miller95def091999-11-25 00:26:21 +110090 memcpy(&iv1, iv2, 8);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100091
Damien Miller95def091999-11-25 00:26:21 +110092 des_cbc_encrypt(src, dest, len, ks3, iv3, DES_DECRYPT);
Damien Miller98c7ad62000-03-09 21:27:49 +110093 memcpy(iv3, src + len - 8, 8);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100094
Damien Miller95def091999-11-25 00:26:21 +110095 des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_ENCRYPT);
Damien Miller98c7ad62000-03-09 21:27:49 +110096 memcpy(iv2, dest + len - 8, 8);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100097
Damien Miller95def091999-11-25 00:26:21 +110098 des_cbc_encrypt(dest, dest, len, ks1, &iv1, DES_DECRYPT);
99 /* memcpy(&iv1, iv2, 8); */
100 /* Note how iv1 == iv2 on entry and exit. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000101}
102
103/*
Damien Miller78928792000-04-12 20:17:38 +1000104 * SSH1 uses a variation on Blowfish, all bytes must be swapped before
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000105 * and after encryption/decryption. Thus the swap_bytes stuff (yuk).
106 */
Damien Miller95def091999-11-25 00:26:21 +1100107static void
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000108swap_bytes(const unsigned char *src, unsigned char *dst_, int n)
109{
Damien Miller95def091999-11-25 00:26:21 +1100110 /* dst must be properly aligned. */
111 u_int32_t *dst = (u_int32_t *) dst_;
112 union {
113 u_int32_t i;
114 char c[4];
115 } t;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000116
Damien Miller95def091999-11-25 00:26:21 +1100117 /* Process 8 bytes every lap. */
118 for (n = n / 8; n > 0; n--) {
119 t.c[3] = *src++;
120 t.c[2] = *src++;
121 t.c[1] = *src++;
122 t.c[0] = *src++;
123 *dst++ = t.i;
124
125 t.c[3] = *src++;
126 t.c[2] = *src++;
127 t.c[1] = *src++;
128 t.c[0] = *src++;
129 *dst++ = t.i;
130 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000131}
132
Damien Miller5428f641999-11-25 11:54:57 +1100133/*
134 * Names of all encryption algorithms.
135 * These must match the numbers defined in cipher.h.
136 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000137static char *cipher_names[] =
138{
Damien Miller95def091999-11-25 00:26:21 +1100139 "none",
140 "idea",
141 "des",
142 "3des",
143 "tss",
Damien Millere4340be2000-09-16 13:29:08 +1100144 "rc4", /* Alleged RC4 */
Damien Millerb38eff82000-04-01 11:09:21 +1000145 "blowfish",
146 "reserved",
147 "blowfish-cbc",
148 "3des-cbc",
149 "arcfour",
150 "cast128-cbc"
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000151};
152
Damien Miller5428f641999-11-25 11:54:57 +1100153/*
154 * Returns a bit mask indicating which ciphers are supported by this
155 * implementation. The bit mask has the corresponding bit set of each
156 * supported cipher.
157 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000158
Damien Miller4af51302000-04-16 11:18:38 +1000159unsigned int
Damien Miller1383bd82000-04-06 12:32:37 +1000160cipher_mask1()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000161{
Damien Miller95def091999-11-25 00:26:21 +1100162 unsigned int mask = 0;
163 mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */
164 mask |= 1 << SSH_CIPHER_BLOWFISH;
Damien Miller1383bd82000-04-06 12:32:37 +1000165 return mask;
166}
Damien Miller4af51302000-04-16 11:18:38 +1000167unsigned int
Damien Miller1383bd82000-04-06 12:32:37 +1000168cipher_mask2()
169{
170 unsigned int mask = 0;
Damien Millerb38eff82000-04-01 11:09:21 +1000171 mask |= 1 << SSH_CIPHER_BLOWFISH_CBC;
172 mask |= 1 << SSH_CIPHER_3DES_CBC;
173 mask |= 1 << SSH_CIPHER_ARCFOUR;
174 mask |= 1 << SSH_CIPHER_CAST128_CBC;
Damien Miller95def091999-11-25 00:26:21 +1100175 return mask;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000176}
Damien Miller4af51302000-04-16 11:18:38 +1000177unsigned int
Damien Miller1383bd82000-04-06 12:32:37 +1000178cipher_mask()
179{
180 return cipher_mask1() | cipher_mask2();
181}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000182
183/* Returns the name of the cipher. */
184
Damien Miller95def091999-11-25 00:26:21 +1100185const char *
186cipher_name(int cipher)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000187{
Damien Miller95def091999-11-25 00:26:21 +1100188 if (cipher < 0 || cipher >= sizeof(cipher_names) / sizeof(cipher_names[0]) ||
189 cipher_names[cipher] == NULL)
Damien Miller78928792000-04-12 20:17:38 +1000190 fatal("cipher_name: bad cipher name: %d", cipher);
Damien Miller95def091999-11-25 00:26:21 +1100191 return cipher_names[cipher];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000192}
193
Damien Miller78928792000-04-12 20:17:38 +1000194/* Returns 1 if the name of the ciphers are valid. */
195
196#define CIPHER_SEP ","
197int
198ciphers_valid(const char *names)
199{
Damien Miller37023962000-07-11 17:31:38 +1000200 char *ciphers, *cp;
Damien Miller78928792000-04-12 20:17:38 +1000201 char *p;
202 int i;
203
Damien Millerb1715dc2000-05-30 13:44:51 +1000204 if (names == NULL || strcmp(names, "") == 0)
Damien Miller78928792000-04-12 20:17:38 +1000205 return 0;
Damien Miller37023962000-07-11 17:31:38 +1000206 ciphers = cp = xstrdup(names);
207 for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
208 (p = strsep(&cp, CIPHER_SEP))) {
Damien Miller78928792000-04-12 20:17:38 +1000209 i = cipher_number(p);
210 if (i == -1 || !(cipher_mask2() & (1 << i))) {
211 xfree(ciphers);
212 return 0;
213 }
214 }
215 xfree(ciphers);
216 return 1;
217}
218
Damien Miller5428f641999-11-25 11:54:57 +1100219/*
220 * Parses the name of the cipher. Returns the number of the corresponding
221 * cipher, or -1 on error.
222 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000223
224int
225cipher_number(const char *name)
226{
Damien Miller95def091999-11-25 00:26:21 +1100227 int i;
Damien Millerb1715dc2000-05-30 13:44:51 +1000228 if (name == NULL)
229 return -1;
Damien Miller95def091999-11-25 00:26:21 +1100230 for (i = 0; i < sizeof(cipher_names) / sizeof(cipher_names[0]); i++)
231 if (strcmp(cipher_names[i], name) == 0 &&
232 (cipher_mask() & (1 << i)))
233 return i;
234 return -1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000235}
236
Damien Miller5428f641999-11-25 11:54:57 +1100237/*
238 * Selects the cipher, and keys if by computing the MD5 checksum of the
239 * passphrase and using the resulting 16 bytes as the key.
240 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000241
Damien Miller4af51302000-04-16 11:18:38 +1000242void
Damien Miller1383bd82000-04-06 12:32:37 +1000243cipher_set_key_string(CipherContext *context, int cipher, const char *passphrase)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000244{
Damien Miller95def091999-11-25 00:26:21 +1100245 MD5_CTX md;
246 unsigned char digest[16];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000247
Damien Miller95def091999-11-25 00:26:21 +1100248 MD5_Init(&md);
249 MD5_Update(&md, (const unsigned char *) passphrase, strlen(passphrase));
250 MD5_Final(digest, &md);
251
Damien Miller1383bd82000-04-06 12:32:37 +1000252 cipher_set_key(context, cipher, digest, 16);
Damien Miller95def091999-11-25 00:26:21 +1100253
254 memset(digest, 0, sizeof(digest));
255 memset(&md, 0, sizeof(md));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000256}
257
258/* Selects the cipher to use and sets the key. */
259
Damien Miller4af51302000-04-16 11:18:38 +1000260void
Damien Miller1383bd82000-04-06 12:32:37 +1000261cipher_set_key(CipherContext *context, int cipher, const unsigned char *key,
262 int keylen)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000263{
Damien Miller95def091999-11-25 00:26:21 +1100264 unsigned char padded[32];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000265
Damien Miller95def091999-11-25 00:26:21 +1100266 /* Set cipher type. */
267 context->type = cipher;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000268
Damien Miller95def091999-11-25 00:26:21 +1100269 /* Get 32 bytes of key data. Pad if necessary. (So that code
270 below does not need to worry about key size). */
271 memset(padded, 0, sizeof(padded));
272 memcpy(padded, key, keylen < sizeof(padded) ? keylen : sizeof(padded));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000273
Damien Miller95def091999-11-25 00:26:21 +1100274 /* Initialize the initialization vector. */
275 switch (cipher) {
276 case SSH_CIPHER_NONE:
Damien Miller5428f641999-11-25 11:54:57 +1100277 /*
278 * Has to stay for authfile saving of private key with no
279 * passphrase
280 */
Damien Miller95def091999-11-25 00:26:21 +1100281 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000282
Damien Miller95def091999-11-25 00:26:21 +1100283 case SSH_CIPHER_3DES:
Damien Miller5428f641999-11-25 11:54:57 +1100284 /*
285 * Note: the least significant bit of each byte of key is
286 * parity, and must be ignored by the implementation. 16
287 * bytes of key are used (first and last keys are the same).
288 */
Damien Miller95def091999-11-25 00:26:21 +1100289 if (keylen < 16)
290 error("Key length %d is insufficient for 3DES.", keylen);
291 des_set_key((void *) padded, context->u.des3.key1);
292 des_set_key((void *) (padded + 8), context->u.des3.key2);
293 if (keylen <= 16)
294 des_set_key((void *) padded, context->u.des3.key3);
295 else
296 des_set_key((void *) (padded + 16), context->u.des3.key3);
297 memset(context->u.des3.iv2, 0, sizeof(context->u.des3.iv2));
298 memset(context->u.des3.iv3, 0, sizeof(context->u.des3.iv3));
299 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000300
Damien Miller95def091999-11-25 00:26:21 +1100301 case SSH_CIPHER_BLOWFISH:
Damien Millerb38eff82000-04-01 11:09:21 +1000302 if (keylen < 16)
303 error("Key length %d is insufficient for blowfish.", keylen);
Damien Miller95def091999-11-25 00:26:21 +1100304 BF_set_key(&context->u.bf.key, keylen, padded);
305 memset(context->u.bf.iv, 0, 8);
306 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000307
Damien Millerb38eff82000-04-01 11:09:21 +1000308 case SSH_CIPHER_3DES_CBC:
309 case SSH_CIPHER_BLOWFISH_CBC:
310 case SSH_CIPHER_ARCFOUR:
311 case SSH_CIPHER_CAST128_CBC:
312 fatal("cipher_set_key: illegal cipher: %s", cipher_name(cipher));
313 break;
314
Damien Miller95def091999-11-25 00:26:21 +1100315 default:
316 fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher));
317 }
318 memset(padded, 0, sizeof(padded));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000319}
320
Damien Miller4af51302000-04-16 11:18:38 +1000321void
Damien Millerb38eff82000-04-01 11:09:21 +1000322cipher_set_key_iv(CipherContext * context, int cipher,
Damien Miller4af51302000-04-16 11:18:38 +1000323 const unsigned char *key, int keylen,
Damien Millerb38eff82000-04-01 11:09:21 +1000324 const unsigned char *iv, int ivlen)
325{
326 /* Set cipher type. */
327 context->type = cipher;
328
329 /* Initialize the initialization vector. */
330 switch (cipher) {
331 case SSH_CIPHER_NONE:
332 break;
333
334 case SSH_CIPHER_3DES:
335 case SSH_CIPHER_BLOWFISH:
336 fatal("cipher_set_key_iv: illegal cipher: %s", cipher_name(cipher));
337 break;
338
339 case SSH_CIPHER_3DES_CBC:
340 if (keylen < 24)
341 error("Key length %d is insufficient for 3des-cbc.", keylen);
342 des_set_key((void *) key, context->u.des3.key1);
343 des_set_key((void *) (key+8), context->u.des3.key2);
344 des_set_key((void *) (key+16), context->u.des3.key3);
345 if (ivlen < 8)
346 error("IV length %d is insufficient for 3des-cbc.", ivlen);
347 memcpy(context->u.des3.iv3, (char *)iv, 8);
348 break;
349
350 case SSH_CIPHER_BLOWFISH_CBC:
351 if (keylen < 16)
352 error("Key length %d is insufficient for blowfish.", keylen);
353 if (ivlen < 8)
354 error("IV length %d is insufficient for blowfish.", ivlen);
355 BF_set_key(&context->u.bf.key, keylen, (unsigned char *)key);
356 memcpy(context->u.bf.iv, (char *)iv, 8);
357 break;
358
359 case SSH_CIPHER_ARCFOUR:
360 if (keylen < 16)
361 error("Key length %d is insufficient for arcfour.", keylen);
362 RC4_set_key(&context->u.rc4, keylen, (unsigned char *)key);
363 break;
364
365 case SSH_CIPHER_CAST128_CBC:
366 if (keylen < 16)
367 error("Key length %d is insufficient for cast128.", keylen);
368 if (ivlen < 8)
369 error("IV length %d is insufficient for cast128.", ivlen);
370 CAST_set_key(&context->u.cast.key, keylen, (unsigned char *) key);
371 memcpy(context->u.cast.iv, (char *)iv, 8);
372 break;
373
374 default:
375 fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher));
376 }
377}
378
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000379/* Encrypts data using the cipher. */
380
Damien Miller4af51302000-04-16 11:18:38 +1000381void
Damien Miller95def091999-11-25 00:26:21 +1100382cipher_encrypt(CipherContext *context, unsigned char *dest,
383 const unsigned char *src, unsigned int len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000384{
Damien Miller95def091999-11-25 00:26:21 +1100385 if ((len & 7) != 0)
386 fatal("cipher_encrypt: bad plaintext length %d", len);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000387
Damien Miller95def091999-11-25 00:26:21 +1100388 switch (context->type) {
389 case SSH_CIPHER_NONE:
390 memcpy(dest, src, len);
391 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000392
Damien Miller95def091999-11-25 00:26:21 +1100393 case SSH_CIPHER_3DES:
394 SSH_3CBC_ENCRYPT(context->u.des3.key1,
395 context->u.des3.key2, &context->u.des3.iv2,
396 context->u.des3.key3, &context->u.des3.iv3,
Damien Miller98c7ad62000-03-09 21:27:49 +1100397 dest, (unsigned char *) src, len);
Damien Miller95def091999-11-25 00:26:21 +1100398 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000399
Damien Miller95def091999-11-25 00:26:21 +1100400 case SSH_CIPHER_BLOWFISH:
401 swap_bytes(src, dest, len);
402 BF_cbc_encrypt(dest, dest, len,
Damien Miller4af51302000-04-16 11:18:38 +1000403 &context->u.bf.key, context->u.bf.iv,
Damien Miller95def091999-11-25 00:26:21 +1100404 BF_ENCRYPT);
405 swap_bytes(dest, dest, len);
406 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000407
Damien Millerb38eff82000-04-01 11:09:21 +1000408 case SSH_CIPHER_BLOWFISH_CBC:
409 BF_cbc_encrypt((void *)src, dest, len,
Damien Miller4af51302000-04-16 11:18:38 +1000410 &context->u.bf.key, context->u.bf.iv,
Damien Millerb38eff82000-04-01 11:09:21 +1000411 BF_ENCRYPT);
412 break;
413
414 case SSH_CIPHER_3DES_CBC:
415 des_ede3_cbc_encrypt(src, dest, len,
416 context->u.des3.key1, context->u.des3.key2,
417 context->u.des3.key3, &context->u.des3.iv3, DES_ENCRYPT);
418 break;
419
420 case SSH_CIPHER_ARCFOUR:
421 RC4(&context->u.rc4, len, (unsigned char *)src, dest);
422 break;
423
424 case SSH_CIPHER_CAST128_CBC:
425 CAST_cbc_encrypt(src, dest, len,
426 &context->u.cast.key, context->u.cast.iv, CAST_ENCRYPT);
427 break;
428
Damien Miller95def091999-11-25 00:26:21 +1100429 default:
430 fatal("cipher_encrypt: unknown cipher: %s", cipher_name(context->type));
431 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000432}
Damien Miller95def091999-11-25 00:26:21 +1100433
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000434/* Decrypts data using the cipher. */
435
Damien Miller4af51302000-04-16 11:18:38 +1000436void
Damien Miller95def091999-11-25 00:26:21 +1100437cipher_decrypt(CipherContext *context, unsigned char *dest,
438 const unsigned char *src, unsigned int len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000439{
Damien Miller95def091999-11-25 00:26:21 +1100440 if ((len & 7) != 0)
441 fatal("cipher_decrypt: bad ciphertext length %d", len);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000442
Damien Miller95def091999-11-25 00:26:21 +1100443 switch (context->type) {
444 case SSH_CIPHER_NONE:
445 memcpy(dest, src, len);
446 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000447
Damien Miller95def091999-11-25 00:26:21 +1100448 case SSH_CIPHER_3DES:
Damien Miller95def091999-11-25 00:26:21 +1100449 SSH_3CBC_DECRYPT(context->u.des3.key1,
450 context->u.des3.key2, &context->u.des3.iv2,
451 context->u.des3.key3, &context->u.des3.iv3,
Damien Miller98c7ad62000-03-09 21:27:49 +1100452 dest, (unsigned char *) src, len);
Damien Miller95def091999-11-25 00:26:21 +1100453 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000454
Damien Miller95def091999-11-25 00:26:21 +1100455 case SSH_CIPHER_BLOWFISH:
Damien Miller95def091999-11-25 00:26:21 +1100456 swap_bytes(src, dest, len);
457 BF_cbc_encrypt((void *) dest, dest, len,
458 &context->u.bf.key, context->u.bf.iv,
459 BF_DECRYPT);
460 swap_bytes(dest, dest, len);
461 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000462
Damien Millerb38eff82000-04-01 11:09:21 +1000463 case SSH_CIPHER_BLOWFISH_CBC:
464 BF_cbc_encrypt((void *) src, dest, len,
465 &context->u.bf.key, context->u.bf.iv,
466 BF_DECRYPT);
467 break;
468
469 case SSH_CIPHER_3DES_CBC:
470 des_ede3_cbc_encrypt(src, dest, len,
471 context->u.des3.key1, context->u.des3.key2,
472 context->u.des3.key3, &context->u.des3.iv3, DES_DECRYPT);
473 break;
474
475 case SSH_CIPHER_ARCFOUR:
476 RC4(&context->u.rc4, len, (unsigned char *)src, dest);
477 break;
478
479 case SSH_CIPHER_CAST128_CBC:
480 CAST_cbc_encrypt(src, dest, len,
481 &context->u.cast.key, context->u.cast.iv, CAST_DECRYPT);
482 break;
483
Damien Miller95def091999-11-25 00:26:21 +1100484 default:
485 fatal("cipher_decrypt: unknown cipher: %s", cipher_name(context->type));
486 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000487}