xref: /openssh-portable/cipher.c (revision 8668706d)
1 /* $OpenBSD: cipher.c,v 1.99 2014/06/24 01:13:21 djm Exp $ */
2 /*
3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5  *                    All rights reserved
6  *
7  * As far as I am concerned, the code I have written for this software
8  * can be used freely for any purpose.  Any derived versions of this
9  * software must be clearly marked as such, and if the derived work is
10  * incompatible with the protocol description in the RFC file, it must be
11  * called by a name other than "ssh" or "Secure Shell".
12  *
13  *
14  * Copyright (c) 1999 Niels Provos.  All rights reserved.
15  * Copyright (c) 1999, 2000 Markus Friedl.  All rights reserved.
16  *
17  * Redistribution and use in source and binary forms, with or without
18  * modification, are permitted provided that the following conditions
19  * are met:
20  * 1. Redistributions of source code must retain the above copyright
21  *    notice, this list of conditions and the following disclaimer.
22  * 2. Redistributions in binary form must reproduce the above copyright
23  *    notice, this list of conditions and the following disclaimer in the
24  *    documentation and/or other materials provided with the distribution.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36  */
37 
38 #include "includes.h"
39 
40 #include <sys/types.h>
41 
42 #include <string.h>
43 #include <stdarg.h>
44 #include <stdio.h>
45 
46 #include "cipher.h"
47 #include "misc.h"
48 #include "sshbuf.h"
49 #include "ssherr.h"
50 #include "digest.h"
51 
52 #ifdef WITH_SSH1
53 extern const EVP_CIPHER *evp_ssh1_bf(void);
54 extern const EVP_CIPHER *evp_ssh1_3des(void);
55 extern int ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
56 #endif
57 
58 struct sshcipher {
59 	char	*name;
60 	int	number;		/* for ssh1 only */
61 	u_int	block_size;
62 	u_int	key_len;
63 	u_int	iv_len;		/* defaults to block_size */
64 	u_int	auth_len;
65 	u_int	discard_len;
66 	u_int	flags;
67 #define CFLAG_CBC		(1<<0)
68 #define CFLAG_CHACHAPOLY	(1<<1)
69 #define CFLAG_AESCTR		(1<<2)
70 #define CFLAG_NONE		(1<<3)
71 #ifdef WITH_OPENSSL
72 	const EVP_CIPHER	*(*evptype)(void);
73 #else
74 	void	*ignored;
75 #endif
76 };
77 
78 static const struct sshcipher ciphers[] = {
79 #ifdef WITH_SSH1
80 	{ "des",	SSH_CIPHER_DES, 8, 8, 0, 0, 0, 1, EVP_des_cbc },
81 	{ "3des",	SSH_CIPHER_3DES, 8, 16, 0, 0, 0, 1, evp_ssh1_3des },
82 	{ "blowfish",	SSH_CIPHER_BLOWFISH, 8, 32, 0, 0, 0, 1, evp_ssh1_bf },
83 #endif /* WITH_SSH1 */
84 #ifdef WITH_OPENSSL
85 	{ "none",	SSH_CIPHER_NONE, 8, 0, 0, 0, 0, 0, EVP_enc_null },
86 	{ "3des-cbc",	SSH_CIPHER_SSH2, 8, 24, 0, 0, 0, 1, EVP_des_ede3_cbc },
87 	{ "blowfish-cbc",
88 			SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 1, EVP_bf_cbc },
89 	{ "cast128-cbc",
90 			SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 1, EVP_cast5_cbc },
91 	{ "arcfour",	SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 0, EVP_rc4 },
92 	{ "arcfour128",	SSH_CIPHER_SSH2, 8, 16, 0, 0, 1536, 0, EVP_rc4 },
93 	{ "arcfour256",	SSH_CIPHER_SSH2, 8, 32, 0, 0, 1536, 0, EVP_rc4 },
94 	{ "aes128-cbc",	SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, 1, EVP_aes_128_cbc },
95 	{ "aes192-cbc",	SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, 1, EVP_aes_192_cbc },
96 	{ "aes256-cbc",	SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 1, EVP_aes_256_cbc },
97 	{ "rijndael-cbc@lysator.liu.se",
98 			SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 1, EVP_aes_256_cbc },
99 	{ "aes128-ctr",	SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, 0, EVP_aes_128_ctr },
100 	{ "aes192-ctr",	SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, 0, EVP_aes_192_ctr },
101 	{ "aes256-ctr",	SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 0, EVP_aes_256_ctr },
102 # ifdef OPENSSL_HAVE_EVPGCM
103 	{ "aes128-gcm@openssh.com",
104 			SSH_CIPHER_SSH2, 16, 16, 12, 16, 0, 0, EVP_aes_128_gcm },
105 	{ "aes256-gcm@openssh.com",
106 			SSH_CIPHER_SSH2, 16, 32, 12, 16, 0, 0, EVP_aes_256_gcm },
107 # endif /* OPENSSL_HAVE_EVPGCM */
108 #else /* WITH_OPENSSL */
109 	{ "aes128-ctr",	SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, CFLAG_AESCTR, NULL },
110 	{ "aes192-ctr",	SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, CFLAG_AESCTR, NULL },
111 	{ "aes256-ctr",	SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, CFLAG_AESCTR, NULL },
112 	{ "none",	SSH_CIPHER_NONE, 8, 0, 0, 0, 0, CFLAG_NONE, NULL },
113 #endif /* WITH_OPENSSL */
114 	{ "chacha20-poly1305@openssh.com",
115 			SSH_CIPHER_SSH2, 8, 64, 0, 16, 0, CFLAG_CHACHAPOLY, NULL },
116 
117 	{ NULL,		SSH_CIPHER_INVALID, 0, 0, 0, 0, 0, 0, NULL }
118 };
119 
120 /*--*/
121 
122 /* Returns a comma-separated list of supported ciphers. */
123 char *
124 cipher_alg_list(char sep, int auth_only)
125 {
126 	char *tmp, *ret = NULL;
127 	size_t nlen, rlen = 0;
128 	const struct sshcipher *c;
129 
130 	for (c = ciphers; c->name != NULL; c++) {
131 		if (c->number != SSH_CIPHER_SSH2)
132 			continue;
133 		if (auth_only && c->auth_len == 0)
134 			continue;
135 		if (ret != NULL)
136 			ret[rlen++] = sep;
137 		nlen = strlen(c->name);
138 		if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) {
139 			free(ret);
140 			return NULL;
141 		}
142 		ret = tmp;
143 		memcpy(ret + rlen, c->name, nlen + 1);
144 		rlen += nlen;
145 	}
146 	return ret;
147 }
148 
149 u_int
150 cipher_blocksize(const struct sshcipher *c)
151 {
152 	return (c->block_size);
153 }
154 
155 u_int
156 cipher_keylen(const struct sshcipher *c)
157 {
158 	return (c->key_len);
159 }
160 
161 u_int
162 cipher_seclen(const struct sshcipher *c)
163 {
164 	if (strcmp("3des-cbc", c->name) == 0)
165 		return 14;
166 	return cipher_keylen(c);
167 }
168 
169 u_int
170 cipher_authlen(const struct sshcipher *c)
171 {
172 	return (c->auth_len);
173 }
174 
175 u_int
176 cipher_ivlen(const struct sshcipher *c)
177 {
178 	/*
179 	 * Default is cipher block size, except for chacha20+poly1305 that
180 	 * needs no IV. XXX make iv_len == -1 default?
181 	 */
182 	return (c->iv_len != 0 || (c->flags & CFLAG_CHACHAPOLY) != 0) ?
183 	    c->iv_len : c->block_size;
184 }
185 
186 u_int
187 cipher_get_number(const struct sshcipher *c)
188 {
189 	return (c->number);
190 }
191 
192 u_int
193 cipher_is_cbc(const struct sshcipher *c)
194 {
195 	return (c->flags & CFLAG_CBC) != 0;
196 }
197 
198 u_int
199 cipher_mask_ssh1(int client)
200 {
201 	u_int mask = 0;
202 	mask |= 1 << SSH_CIPHER_3DES;		/* Mandatory */
203 	mask |= 1 << SSH_CIPHER_BLOWFISH;
204 	if (client) {
205 		mask |= 1 << SSH_CIPHER_DES;
206 	}
207 	return mask;
208 }
209 
210 const struct sshcipher *
211 cipher_by_name(const char *name)
212 {
213 	const struct sshcipher *c;
214 	for (c = ciphers; c->name != NULL; c++)
215 		if (strcmp(c->name, name) == 0)
216 			return c;
217 	return NULL;
218 }
219 
220 const struct sshcipher *
221 cipher_by_number(int id)
222 {
223 	const struct sshcipher *c;
224 	for (c = ciphers; c->name != NULL; c++)
225 		if (c->number == id)
226 			return c;
227 	return NULL;
228 }
229 
230 #define	CIPHER_SEP	","
231 int
232 ciphers_valid(const char *names)
233 {
234 	const struct sshcipher *c;
235 	char *cipher_list, *cp;
236 	char *p;
237 
238 	if (names == NULL || strcmp(names, "") == 0)
239 		return 0;
240 	if ((cipher_list = cp = strdup(names)) == NULL)
241 		return 0;
242 	for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
243 	    (p = strsep(&cp, CIPHER_SEP))) {
244 		c = cipher_by_name(p);
245 		if (c == NULL || c->number != SSH_CIPHER_SSH2) {
246 			free(cipher_list);
247 			return 0;
248 		}
249 	}
250 	free(cipher_list);
251 	return 1;
252 }
253 
254 /*
255  * Parses the name of the cipher.  Returns the number of the corresponding
256  * cipher, or -1 on error.
257  */
258 
259 int
260 cipher_number(const char *name)
261 {
262 	const struct sshcipher *c;
263 	if (name == NULL)
264 		return -1;
265 	for (c = ciphers; c->name != NULL; c++)
266 		if (strcasecmp(c->name, name) == 0)
267 			return c->number;
268 	return -1;
269 }
270 
271 char *
272 cipher_name(int id)
273 {
274 	const struct sshcipher *c = cipher_by_number(id);
275 	return (c==NULL) ? "<unknown>" : c->name;
276 }
277 
278 const char *
279 cipher_warning_message(const struct sshcipher_ctx *cc)
280 {
281 	if (cc == NULL || cc->cipher == NULL)
282 		return NULL;
283 	if (cc->cipher->number == SSH_CIPHER_DES)
284 		return "use of DES is strongly discouraged due to "
285 		    "cryptographic weaknesses";
286 	return NULL;
287 }
288 
289 int
290 cipher_init(struct sshcipher_ctx *cc, const struct sshcipher *cipher,
291     const u_char *key, u_int keylen, const u_char *iv, u_int ivlen,
292     int do_encrypt)
293 {
294 #ifdef WITH_OPENSSL
295 	int ret = SSH_ERR_INTERNAL_ERROR;
296 	const EVP_CIPHER *type;
297 	int klen;
298 	u_char *junk, *discard;
299 
300 	if (cipher->number == SSH_CIPHER_DES) {
301 		if (keylen > 8)
302 			keylen = 8;
303 	}
304 #endif
305 	cc->plaintext = (cipher->number == SSH_CIPHER_NONE);
306 	cc->encrypt = do_encrypt;
307 
308 	if (keylen < cipher->key_len ||
309 	    (iv != NULL && ivlen < cipher_ivlen(cipher)))
310 		return SSH_ERR_INVALID_ARGUMENT;
311 
312 	cc->cipher = cipher;
313 	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
314 		return chachapoly_init(&cc->cp_ctx, key, keylen);
315 	}
316 #ifndef WITH_OPENSSL
317 	if ((cc->cipher->flags & CFLAG_AESCTR) != 0) {
318 		aesctr_keysetup(&cc->ac_ctx, key, 8 * keylen, 8 * ivlen);
319 		aesctr_ivsetup(&cc->ac_ctx, iv);
320 		return 0;
321 	}
322 	if ((cc->cipher->flags & CFLAG_NONE) != 0)
323 		return 0;
324 	return SSH_ERR_INVALID_ARGUMENT;
325 #else
326 	type = (*cipher->evptype)();
327 	EVP_CIPHER_CTX_init(&cc->evp);
328 	if (EVP_CipherInit(&cc->evp, type, NULL, (u_char *)iv,
329 	    (do_encrypt == CIPHER_ENCRYPT)) == 0) {
330 		ret = SSH_ERR_LIBCRYPTO_ERROR;
331 		goto bad;
332 	}
333 	if (cipher_authlen(cipher) &&
334 	    !EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_SET_IV_FIXED,
335 	    -1, (u_char *)iv)) {
336 		ret = SSH_ERR_LIBCRYPTO_ERROR;
337 		goto bad;
338 	}
339 	klen = EVP_CIPHER_CTX_key_length(&cc->evp);
340 	if (klen > 0 && keylen != (u_int)klen) {
341 		if (EVP_CIPHER_CTX_set_key_length(&cc->evp, keylen) == 0) {
342 			ret = SSH_ERR_LIBCRYPTO_ERROR;
343 			goto bad;
344 		}
345 	}
346 	if (EVP_CipherInit(&cc->evp, NULL, (u_char *)key, NULL, -1) == 0) {
347 		ret = SSH_ERR_LIBCRYPTO_ERROR;
348 		goto bad;
349 	}
350 
351 	if (cipher->discard_len > 0) {
352 		if ((junk = malloc(cipher->discard_len)) == NULL ||
353 		    (discard = malloc(cipher->discard_len)) == NULL) {
354 			if (junk != NULL)
355 				free(junk);
356 			ret = SSH_ERR_ALLOC_FAIL;
357 			goto bad;
358 		}
359 		ret = EVP_Cipher(&cc->evp, discard, junk, cipher->discard_len);
360 		explicit_bzero(discard, cipher->discard_len);
361 		free(junk);
362 		free(discard);
363 		if (ret != 1) {
364 			ret = SSH_ERR_LIBCRYPTO_ERROR;
365  bad:
366 			EVP_CIPHER_CTX_cleanup(&cc->evp);
367 			return ret;
368 		}
369 	}
370 #endif
371 	return 0;
372 }
373 
374 /*
375  * cipher_crypt() operates as following:
376  * Copy 'aadlen' bytes (without en/decryption) from 'src' to 'dest'.
377  * Theses bytes are treated as additional authenticated data for
378  * authenticated encryption modes.
379  * En/Decrypt 'len' bytes at offset 'aadlen' from 'src' to 'dest'.
380  * Use 'authlen' bytes at offset 'len'+'aadlen' as the authentication tag.
381  * This tag is written on encryption and verified on decryption.
382  * Both 'aadlen' and 'authlen' can be set to 0.
383  */
384 int
385 cipher_crypt(struct sshcipher_ctx *cc, u_int seqnr, u_char *dest,
386    const u_char *src, u_int len, u_int aadlen, u_int authlen)
387 {
388 	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
389 		return chachapoly_crypt(&cc->cp_ctx, seqnr, dest, src,
390 		    len, aadlen, authlen, cc->encrypt);
391 	}
392 #ifndef WITH_OPENSSL
393 	if ((cc->cipher->flags & CFLAG_AESCTR) != 0) {
394 		if (aadlen)
395 			memcpy(dest, src, aadlen);
396 		aesctr_encrypt_bytes(&cc->ac_ctx, src + aadlen,
397 		    dest + aadlen, len);
398 		return 0;
399 	}
400 	if ((cc->cipher->flags & CFLAG_NONE) != 0) {
401 		memcpy(dest, src, aadlen + len);
402 		return 0;
403 	}
404 	return SSH_ERR_INVALID_ARGUMENT;
405 #else
406 	if (authlen) {
407 		u_char lastiv[1];
408 
409 		if (authlen != cipher_authlen(cc->cipher))
410 			return SSH_ERR_INVALID_ARGUMENT;
411 		/* increment IV */
412 		if (!EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_IV_GEN,
413 		    1, lastiv))
414 			return SSH_ERR_LIBCRYPTO_ERROR;
415 		/* set tag on decyption */
416 		if (!cc->encrypt &&
417 		    !EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_SET_TAG,
418 		    authlen, (u_char *)src + aadlen + len))
419 			return SSH_ERR_LIBCRYPTO_ERROR;
420 	}
421 	if (aadlen) {
422 		if (authlen &&
423 		    EVP_Cipher(&cc->evp, NULL, (u_char *)src, aadlen) < 0)
424 			return SSH_ERR_LIBCRYPTO_ERROR;
425 		memcpy(dest, src, aadlen);
426 	}
427 	if (len % cc->cipher->block_size)
428 		return SSH_ERR_INVALID_ARGUMENT;
429 	if (EVP_Cipher(&cc->evp, dest + aadlen, (u_char *)src + aadlen,
430 	    len) < 0)
431 		return SSH_ERR_LIBCRYPTO_ERROR;
432 	if (authlen) {
433 		/* compute tag (on encrypt) or verify tag (on decrypt) */
434 		if (EVP_Cipher(&cc->evp, NULL, NULL, 0) < 0)
435 			return cc->encrypt ?
436 			    SSH_ERR_LIBCRYPTO_ERROR : SSH_ERR_MAC_INVALID;
437 		if (cc->encrypt &&
438 		    !EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_GET_TAG,
439 		    authlen, dest + aadlen + len))
440 			return SSH_ERR_LIBCRYPTO_ERROR;
441 	}
442 	return 0;
443 #endif
444 }
445 
446 /* Extract the packet length, including any decryption necessary beforehand */
447 int
448 cipher_get_length(struct sshcipher_ctx *cc, u_int *plenp, u_int seqnr,
449     const u_char *cp, u_int len)
450 {
451 	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
452 		return chachapoly_get_length(&cc->cp_ctx, plenp, seqnr,
453 		    cp, len);
454 	if (len < 4)
455 		return SSH_ERR_MESSAGE_INCOMPLETE;
456 	*plenp = get_u32(cp);
457 	return 0;
458 }
459 
460 int
461 cipher_cleanup(struct sshcipher_ctx *cc)
462 {
463 	if (cc == NULL || cc->cipher == NULL)
464 		return 0;
465 	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
466 		explicit_bzero(&cc->cp_ctx, sizeof(cc->cp_ctx));
467 	else if ((cc->cipher->flags & CFLAG_AESCTR) != 0)
468 		explicit_bzero(&cc->ac_ctx, sizeof(cc->ac_ctx));
469 #ifdef WITH_OPENSSL
470 	else if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0)
471 		return SSH_ERR_LIBCRYPTO_ERROR;
472 #endif
473 	return 0;
474 }
475 
476 /*
477  * Selects the cipher, and keys if by computing the MD5 checksum of the
478  * passphrase and using the resulting 16 bytes as the key.
479  */
480 int
481 cipher_set_key_string(struct sshcipher_ctx *cc, const struct sshcipher *cipher,
482     const char *passphrase, int do_encrypt)
483 {
484 	u_char digest[16];
485 	int r = SSH_ERR_INTERNAL_ERROR;
486 
487 	if ((r = ssh_digest_memory(SSH_DIGEST_MD5,
488 	    passphrase, strlen(passphrase),
489 	    digest, sizeof(digest))) != 0)
490 		goto out;
491 
492 	r = cipher_init(cc, cipher, digest, 16, NULL, 0, do_encrypt);
493  out:
494 	explicit_bzero(digest, sizeof(digest));
495 	return r;
496 }
497 
498 /*
499  * Exports an IV from the sshcipher_ctx required to export the key
500  * state back from the unprivileged child to the privileged parent
501  * process.
502  */
503 int
504 cipher_get_keyiv_len(const struct sshcipher_ctx *cc)
505 {
506 	const struct sshcipher *c = cc->cipher;
507 	int ivlen = 0;
508 
509 	if (c->number == SSH_CIPHER_3DES)
510 		ivlen = 24;
511 	else if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
512 		ivlen = 0;
513 #ifdef WITH_OPENSSL
514 	else
515 		ivlen = EVP_CIPHER_CTX_iv_length(&cc->evp);
516 #endif /* WITH_OPENSSL */
517 	return (ivlen);
518 }
519 
520 int
521 cipher_get_keyiv(struct sshcipher_ctx *cc, u_char *iv, u_int len)
522 {
523 	const struct sshcipher *c = cc->cipher;
524 #ifdef WITH_OPENSSL
525  	int evplen;
526 #endif
527 
528 	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
529 		if (len != 0)
530 			return SSH_ERR_INVALID_ARGUMENT;
531 		return 0;
532 	}
533 	if ((cc->cipher->flags & CFLAG_NONE) != 0)
534 		return 0;
535 
536 	switch (c->number) {
537 #ifdef WITH_OPENSSL
538 	case SSH_CIPHER_SSH2:
539 	case SSH_CIPHER_DES:
540 	case SSH_CIPHER_BLOWFISH:
541 		evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
542 		if (evplen == 0)
543 			return 0;
544 		else if (evplen < 0)
545 			return SSH_ERR_LIBCRYPTO_ERROR;
546 		if ((u_int)evplen != len)
547 			return SSH_ERR_INVALID_ARGUMENT;
548 		if (cipher_authlen(c)) {
549 			if (!EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_IV_GEN,
550 			   len, iv))
551 			       return SSH_ERR_LIBCRYPTO_ERROR;
552 		} else
553 			memcpy(iv, cc->evp.iv, len);
554 		break;
555 #endif
556 #ifdef WITH_SSH1
557 	case SSH_CIPHER_3DES:
558 		return ssh1_3des_iv(&cc->evp, 0, iv, 24);
559 #endif
560 	default:
561 		return SSH_ERR_INVALID_ARGUMENT;
562 	}
563 	return 0;
564 }
565 
566 int
567 cipher_set_keyiv(struct sshcipher_ctx *cc, const u_char *iv)
568 {
569 	const struct sshcipher *c = cc->cipher;
570 #ifdef WITH_OPENSSL
571  	int evplen = 0;
572 #endif
573 
574 	if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
575 		return 0;
576 	if ((cc->cipher->flags & CFLAG_NONE) != 0)
577 		return 0;
578 
579 	switch (c->number) {
580 #ifdef WITH_OPENSSL
581 	case SSH_CIPHER_SSH2:
582 	case SSH_CIPHER_DES:
583 	case SSH_CIPHER_BLOWFISH:
584 		evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
585 		if (evplen <= 0)
586 			return SSH_ERR_LIBCRYPTO_ERROR;
587 		if (cipher_authlen(c)) {
588 			/* XXX iv arg is const, but EVP_CIPHER_CTX_ctrl isn't */
589 			if (!EVP_CIPHER_CTX_ctrl(&cc->evp,
590 			    EVP_CTRL_GCM_SET_IV_FIXED, -1, (void *)iv))
591 				return SSH_ERR_LIBCRYPTO_ERROR;
592 		} else
593 			memcpy(cc->evp.iv, iv, evplen);
594 		break;
595 #endif
596 #ifdef WITH_SSH1
597 	case SSH_CIPHER_3DES:
598 		return ssh1_3des_iv(&cc->evp, 1, (u_char *)iv, 24);
599 #endif
600 	default:
601 		return SSH_ERR_INVALID_ARGUMENT;
602 	}
603 	return 0;
604 }
605 
606 #ifdef WITH_OPENSSL
607 #define EVP_X_STATE(evp)	(evp).cipher_data
608 #define EVP_X_STATE_LEN(evp)	(evp).cipher->ctx_size
609 #endif
610 
611 int
612 cipher_get_keycontext(const struct sshcipher_ctx *cc, u_char *dat)
613 {
614 #ifdef WITH_OPENSSL
615 	const struct sshcipher *c = cc->cipher;
616 	int plen = 0;
617 
618 	if (c->evptype == EVP_rc4) {
619 		plen = EVP_X_STATE_LEN(cc->evp);
620 		if (dat == NULL)
621 			return (plen);
622 		memcpy(dat, EVP_X_STATE(cc->evp), plen);
623 	}
624 	return (plen);
625 #else
626 	return 0;
627 #endif
628 }
629 
630 void
631 cipher_set_keycontext(struct sshcipher_ctx *cc, const u_char *dat)
632 {
633 #ifdef WITH_OPENSSL
634 	const struct sshcipher *c = cc->cipher;
635 	int plen;
636 
637 	if (c->evptype == EVP_rc4) {
638 		plen = EVP_X_STATE_LEN(cc->evp);
639 		memcpy(EVP_X_STATE(cc->evp), dat, plen);
640 	}
641 #endif
642 }
643