1 /* $OpenBSD: cipher.c,v 1.100 2015/01/14 10:29:45 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 #include "openssl-compat.h"
53
54 #ifdef WITH_SSH1
55 extern const EVP_CIPHER *evp_ssh1_bf(void);
56 extern const EVP_CIPHER *evp_ssh1_3des(void);
57 extern int ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
58 #endif
59
60 struct sshcipher {
61 char *name;
62 int number; /* for ssh1 only */
63 u_int block_size;
64 u_int key_len;
65 u_int iv_len; /* defaults to block_size */
66 u_int auth_len;
67 u_int discard_len;
68 u_int flags;
69 #define CFLAG_CBC (1<<0)
70 #define CFLAG_CHACHAPOLY (1<<1)
71 #define CFLAG_AESCTR (1<<2)
72 #define CFLAG_NONE (1<<3)
73 #ifdef WITH_OPENSSL
74 const EVP_CIPHER *(*evptype)(void);
75 #else
76 void *ignored;
77 #endif
78 };
79
80 static const struct sshcipher ciphers[] = {
81 #ifdef WITH_SSH1
82 { "des", SSH_CIPHER_DES, 8, 8, 0, 0, 0, 1, EVP_des_cbc },
83 { "3des", SSH_CIPHER_3DES, 8, 16, 0, 0, 0, 1, evp_ssh1_3des },
84 { "blowfish", SSH_CIPHER_BLOWFISH, 8, 32, 0, 0, 0, 1, evp_ssh1_bf },
85 #endif /* WITH_SSH1 */
86 #ifdef WITH_OPENSSL
87 { "none", SSH_CIPHER_NONE, 8, 0, 0, 0, 0, 0, EVP_enc_null },
88 { "3des-cbc", SSH_CIPHER_SSH2, 8, 24, 0, 0, 0, 1, EVP_des_ede3_cbc },
89 { "blowfish-cbc",
90 SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 1, EVP_bf_cbc },
91 { "cast128-cbc",
92 SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 1, EVP_cast5_cbc },
93 { "arcfour", SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 0, EVP_rc4 },
94 { "arcfour128", SSH_CIPHER_SSH2, 8, 16, 0, 0, 1536, 0, EVP_rc4 },
95 { "arcfour256", SSH_CIPHER_SSH2, 8, 32, 0, 0, 1536, 0, EVP_rc4 },
96 { "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, 1, EVP_aes_128_cbc },
97 { "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, 1, EVP_aes_192_cbc },
98 { "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 1, EVP_aes_256_cbc },
99 { "rijndael-cbc@lysator.liu.se",
100 SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 1, EVP_aes_256_cbc },
101 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, 0, EVP_aes_128_ctr },
102 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, 0, EVP_aes_192_ctr },
103 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 0, EVP_aes_256_ctr },
104 # ifdef OPENSSL_HAVE_EVPGCM
105 { "aes128-gcm@openssh.com",
106 SSH_CIPHER_SSH2, 16, 16, 12, 16, 0, 0, EVP_aes_128_gcm },
107 { "aes256-gcm@openssh.com",
108 SSH_CIPHER_SSH2, 16, 32, 12, 16, 0, 0, EVP_aes_256_gcm },
109 # endif /* OPENSSL_HAVE_EVPGCM */
110 #else /* WITH_OPENSSL */
111 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, CFLAG_AESCTR, NULL },
112 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, CFLAG_AESCTR, NULL },
113 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, CFLAG_AESCTR, NULL },
114 { "none", SSH_CIPHER_NONE, 8, 0, 0, 0, 0, CFLAG_NONE, NULL },
115 #endif /* WITH_OPENSSL */
116 { "chacha20-poly1305@openssh.com",
117 SSH_CIPHER_SSH2, 8, 64, 0, 16, 0, CFLAG_CHACHAPOLY, NULL },
118
119 { NULL, SSH_CIPHER_INVALID, 0, 0, 0, 0, 0, 0, NULL }
120 };
121
122 /*--*/
123
124 /* Returns a comma-separated list of supported ciphers. */
125 char *
cipher_alg_list(char sep,int auth_only)126 cipher_alg_list(char sep, int auth_only)
127 {
128 char *tmp, *ret = NULL;
129 size_t nlen, rlen = 0;
130 const struct sshcipher *c;
131
132 for (c = ciphers; c->name != NULL; c++) {
133 if (c->number != SSH_CIPHER_SSH2)
134 continue;
135 if (auth_only && c->auth_len == 0)
136 continue;
137 if (ret != NULL)
138 ret[rlen++] = sep;
139 nlen = strlen(c->name);
140 if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) {
141 free(ret);
142 return NULL;
143 }
144 ret = tmp;
145 memcpy(ret + rlen, c->name, nlen + 1);
146 rlen += nlen;
147 }
148 return ret;
149 }
150
151 u_int
cipher_blocksize(const struct sshcipher * c)152 cipher_blocksize(const struct sshcipher *c)
153 {
154 return (c->block_size);
155 }
156
157 u_int
cipher_keylen(const struct sshcipher * c)158 cipher_keylen(const struct sshcipher *c)
159 {
160 return (c->key_len);
161 }
162
163 u_int
cipher_seclen(const struct sshcipher * c)164 cipher_seclen(const struct sshcipher *c)
165 {
166 if (strcmp("3des-cbc", c->name) == 0)
167 return 14;
168 return cipher_keylen(c);
169 }
170
171 u_int
cipher_authlen(const struct sshcipher * c)172 cipher_authlen(const struct sshcipher *c)
173 {
174 return (c->auth_len);
175 }
176
177 u_int
cipher_ivlen(const struct sshcipher * c)178 cipher_ivlen(const struct sshcipher *c)
179 {
180 /*
181 * Default is cipher block size, except for chacha20+poly1305 that
182 * needs no IV. XXX make iv_len == -1 default?
183 */
184 return (c->iv_len != 0 || (c->flags & CFLAG_CHACHAPOLY) != 0) ?
185 c->iv_len : c->block_size;
186 }
187
188 u_int
cipher_get_number(const struct sshcipher * c)189 cipher_get_number(const struct sshcipher *c)
190 {
191 return (c->number);
192 }
193
194 u_int
cipher_is_cbc(const struct sshcipher * c)195 cipher_is_cbc(const struct sshcipher *c)
196 {
197 return (c->flags & CFLAG_CBC) != 0;
198 }
199
200 u_int
cipher_mask_ssh1(int client)201 cipher_mask_ssh1(int client)
202 {
203 u_int mask = 0;
204 mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */
205 mask |= 1 << SSH_CIPHER_BLOWFISH;
206 if (client) {
207 mask |= 1 << SSH_CIPHER_DES;
208 }
209 return mask;
210 }
211
212 const struct sshcipher *
cipher_by_name(const char * name)213 cipher_by_name(const char *name)
214 {
215 const struct sshcipher *c;
216 for (c = ciphers; c->name != NULL; c++)
217 if (strcmp(c->name, name) == 0)
218 return c;
219 return NULL;
220 }
221
222 const struct sshcipher *
cipher_by_number(int id)223 cipher_by_number(int id)
224 {
225 const struct sshcipher *c;
226 for (c = ciphers; c->name != NULL; c++)
227 if (c->number == id)
228 return c;
229 return NULL;
230 }
231
232 #define CIPHER_SEP ","
233 int
ciphers_valid(const char * names)234 ciphers_valid(const char *names)
235 {
236 const struct sshcipher *c;
237 char *cipher_list, *cp;
238 char *p;
239
240 if (names == NULL || strcmp(names, "") == 0)
241 return 0;
242 if ((cipher_list = cp = strdup(names)) == NULL)
243 return 0;
244 for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
245 (p = strsep(&cp, CIPHER_SEP))) {
246 c = cipher_by_name(p);
247 if (c == NULL || c->number != SSH_CIPHER_SSH2) {
248 free(cipher_list);
249 return 0;
250 }
251 }
252 free(cipher_list);
253 return 1;
254 }
255
256 /*
257 * Parses the name of the cipher. Returns the number of the corresponding
258 * cipher, or -1 on error.
259 */
260
261 int
cipher_number(const char * name)262 cipher_number(const char *name)
263 {
264 const struct sshcipher *c;
265 if (name == NULL)
266 return -1;
267 for (c = ciphers; c->name != NULL; c++)
268 #ifndef WIN32
269 if (strcasecmp(c->name, name) == 0)
270 #else
271 if (stricmp(c->name, name) == 0)
272 #endif
273 return c->number;
274 return -1;
275 }
276
277 char *
cipher_name(int id)278 cipher_name(int id)
279 {
280 const struct sshcipher *c = cipher_by_number(id);
281 return (c==NULL) ? "<unknown>" : c->name;
282 }
283
284 const char *
cipher_warning_message(const struct sshcipher_ctx * cc)285 cipher_warning_message(const struct sshcipher_ctx *cc)
286 {
287 if (cc == NULL || cc->cipher == NULL)
288 return NULL;
289 if (cc->cipher->number == SSH_CIPHER_DES)
290 return "use of DES is strongly discouraged due to "
291 "cryptographic weaknesses";
292 return NULL;
293 }
294
295 int
cipher_init(struct sshcipher_ctx * cc,const struct sshcipher * cipher,const u_char * key,u_int keylen,const u_char * iv,u_int ivlen,int do_encrypt)296 cipher_init(struct sshcipher_ctx *cc, const struct sshcipher *cipher,
297 const u_char *key, u_int keylen, const u_char *iv, u_int ivlen,
298 int do_encrypt)
299 {
300 #ifdef WITH_OPENSSL
301 int ret = SSH_ERR_INTERNAL_ERROR;
302 const EVP_CIPHER *type;
303 int klen;
304 u_char *junk, *discard;
305
306 if (cipher->number == SSH_CIPHER_DES) {
307 if (keylen > 8)
308 keylen = 8;
309 }
310 #endif
311 cc->plaintext = (cipher->number == SSH_CIPHER_NONE);
312 cc->encrypt = do_encrypt;
313
314 if (keylen < cipher->key_len ||
315 (iv != NULL && ivlen < cipher_ivlen(cipher)))
316 return SSH_ERR_INVALID_ARGUMENT;
317
318 cc->cipher = cipher;
319 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
320 return chachapoly_init(&cc->cp_ctx, key, keylen);
321 }
322 #ifndef WITH_OPENSSL
323 if ((cc->cipher->flags & CFLAG_AESCTR) != 0) {
324 aesctr_keysetup(&cc->ac_ctx, key, 8 * keylen, 8 * ivlen);
325 aesctr_ivsetup(&cc->ac_ctx, iv);
326 return 0;
327 }
328 if ((cc->cipher->flags & CFLAG_NONE) != 0)
329 return 0;
330 return SSH_ERR_INVALID_ARGUMENT;
331 #else
332 type = (*cipher->evptype)();
333 cc->evp = EVP_CIPHER_CTX_new();
334 if (EVP_CipherInit(cc->evp, type, NULL, (u_char *)iv,
335 (do_encrypt == CIPHER_ENCRYPT)) == 0) {
336 ret = SSH_ERR_LIBCRYPTO_ERROR;
337 goto bad;
338 }
339 if (cipher_authlen(cipher) &&
340 !EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_SET_IV_FIXED,
341 -1, (u_char *)iv)) {
342 ret = SSH_ERR_LIBCRYPTO_ERROR;
343 goto bad;
344 }
345 klen = EVP_CIPHER_CTX_key_length(cc->evp);
346 if (klen > 0 && keylen != (u_int)klen) {
347 if (EVP_CIPHER_CTX_set_key_length(cc->evp, keylen) == 0) {
348 ret = SSH_ERR_LIBCRYPTO_ERROR;
349 goto bad;
350 }
351 }
352 if (EVP_CipherInit(cc->evp, NULL, (u_char *)key, NULL, -1) == 0) {
353 ret = SSH_ERR_LIBCRYPTO_ERROR;
354 goto bad;
355 }
356
357 if (cipher->discard_len > 0) {
358 if ((junk = malloc(cipher->discard_len)) == NULL ||
359 (discard = malloc(cipher->discard_len)) == NULL) {
360 if (junk != NULL)
361 free(junk);
362 ret = SSH_ERR_ALLOC_FAIL;
363 goto bad;
364 }
365 ret = EVP_Cipher(cc->evp, discard, junk, cipher->discard_len);
366 explicit_bzero(discard, cipher->discard_len);
367 free(junk);
368 free(discard);
369 if (ret != 1) {
370 ret = SSH_ERR_LIBCRYPTO_ERROR;
371 bad:
372 EVP_CIPHER_CTX_free(cc->evp);
373 return ret;
374 }
375 }
376 #endif
377 return 0;
378 }
379
380 /*
381 * cipher_crypt() operates as following:
382 * Copy 'aadlen' bytes (without en/decryption) from 'src' to 'dest'.
383 * Theses bytes are treated as additional authenticated data for
384 * authenticated encryption modes.
385 * En/Decrypt 'len' bytes at offset 'aadlen' from 'src' to 'dest'.
386 * Use 'authlen' bytes at offset 'len'+'aadlen' as the authentication tag.
387 * This tag is written on encryption and verified on decryption.
388 * Both 'aadlen' and 'authlen' can be set to 0.
389 */
390 int
cipher_crypt(struct sshcipher_ctx * cc,u_int seqnr,u_char * dest,const u_char * src,u_int len,u_int aadlen,u_int authlen)391 cipher_crypt(struct sshcipher_ctx *cc, u_int seqnr, u_char *dest,
392 const u_char *src, u_int len, u_int aadlen, u_int authlen)
393 {
394 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
395 return chachapoly_crypt(&cc->cp_ctx, seqnr, dest, src,
396 len, aadlen, authlen, cc->encrypt);
397 }
398 #ifndef WITH_OPENSSL
399 if ((cc->cipher->flags & CFLAG_AESCTR) != 0) {
400 if (aadlen)
401 memcpy(dest, src, aadlen);
402 aesctr_encrypt_bytes(&cc->ac_ctx, src + aadlen,
403 dest + aadlen, len);
404 return 0;
405 }
406 if ((cc->cipher->flags & CFLAG_NONE) != 0) {
407 memcpy(dest, src, aadlen + len);
408 return 0;
409 }
410 return SSH_ERR_INVALID_ARGUMENT;
411 #else
412 if (authlen) {
413 u_char lastiv[1];
414
415 if (authlen != cipher_authlen(cc->cipher))
416 return SSH_ERR_INVALID_ARGUMENT;
417 /* increment IV */
418 if (!EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_IV_GEN,
419 1, lastiv))
420 return SSH_ERR_LIBCRYPTO_ERROR;
421 /* set tag on decyption */
422 if (!cc->encrypt &&
423 !EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_SET_TAG,
424 authlen, (u_char *)src + aadlen + len))
425 return SSH_ERR_LIBCRYPTO_ERROR;
426 }
427 if (aadlen) {
428 if (authlen &&
429 EVP_Cipher(cc->evp, NULL, (u_char *)src, aadlen) < 0)
430 return SSH_ERR_LIBCRYPTO_ERROR;
431 memcpy(dest, src, aadlen);
432 }
433 if (len % cc->cipher->block_size)
434 return SSH_ERR_INVALID_ARGUMENT;
435 if (EVP_Cipher(cc->evp, dest + aadlen, (u_char *)src + aadlen,
436 len) < 0)
437 return SSH_ERR_LIBCRYPTO_ERROR;
438 if (authlen) {
439 /* compute tag (on encrypt) or verify tag (on decrypt) */
440 if (EVP_Cipher(cc->evp, NULL, NULL, 0) < 0)
441 return cc->encrypt ?
442 SSH_ERR_LIBCRYPTO_ERROR : SSH_ERR_MAC_INVALID;
443 if (cc->encrypt &&
444 !EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_GET_TAG,
445 authlen, dest + aadlen + len))
446 return SSH_ERR_LIBCRYPTO_ERROR;
447 }
448 return 0;
449 #endif
450 }
451
452 /* Extract the packet length, including any decryption necessary beforehand */
453 int
cipher_get_length(struct sshcipher_ctx * cc,u_int * plenp,u_int seqnr,const u_char * cp,u_int len)454 cipher_get_length(struct sshcipher_ctx *cc, u_int *plenp, u_int seqnr,
455 const u_char *cp, u_int len)
456 {
457 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
458 return chachapoly_get_length(&cc->cp_ctx, plenp, seqnr,
459 cp, len);
460 if (len < 4)
461 return SSH_ERR_MESSAGE_INCOMPLETE;
462 *plenp = get_u32(cp);
463 return 0;
464 }
465
466 int
cipher_cleanup(struct sshcipher_ctx * cc)467 cipher_cleanup(struct sshcipher_ctx *cc)
468 {
469 if (cc == NULL || cc->cipher == NULL)
470 return 0;
471 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
472 explicit_bzero(&cc->cp_ctx, sizeof(cc->cp_ctx));
473 else if ((cc->cipher->flags & CFLAG_AESCTR) != 0)
474 explicit_bzero(&cc->ac_ctx, sizeof(cc->ac_ctx));
475 #ifdef WITH_OPENSSL
476 EVP_CIPHER_CTX_free(cc->evp);
477 #endif
478 return 0;
479 }
480
481 /*
482 * Selects the cipher, and keys if by computing the MD5 checksum of the
483 * passphrase and using the resulting 16 bytes as the key.
484 */
485 int
cipher_set_key_string(struct sshcipher_ctx * cc,const struct sshcipher * cipher,const char * passphrase,int do_encrypt)486 cipher_set_key_string(struct sshcipher_ctx *cc, const struct sshcipher *cipher,
487 const char *passphrase, int do_encrypt)
488 {
489 u_char digest[16];
490 int r = SSH_ERR_INTERNAL_ERROR;
491
492 if ((r = ssh_digest_memory(SSH_DIGEST_MD5,
493 passphrase, strlen(passphrase),
494 digest, sizeof(digest))) != 0)
495 goto out;
496
497 r = cipher_init(cc, cipher, digest, 16, NULL, 0, do_encrypt);
498 out:
499 explicit_bzero(digest, sizeof(digest));
500 return r;
501 }
502
503 /*
504 * Exports an IV from the sshcipher_ctx required to export the key
505 * state back from the unprivileged child to the privileged parent
506 * process.
507 */
508 int
cipher_get_keyiv_len(const struct sshcipher_ctx * cc)509 cipher_get_keyiv_len(const struct sshcipher_ctx *cc)
510 {
511 const struct sshcipher *c = cc->cipher;
512 int ivlen = 0;
513
514 if (c->number == SSH_CIPHER_3DES)
515 ivlen = 24;
516 else if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
517 ivlen = 0;
518 else if ((cc->cipher->flags & CFLAG_AESCTR) != 0)
519 ivlen = sizeof(cc->ac_ctx.ctr);
520 #ifdef WITH_OPENSSL
521 else
522 ivlen = EVP_CIPHER_CTX_iv_length(cc->evp);
523 #endif /* WITH_OPENSSL */
524 return (ivlen);
525 }
526
527 int
cipher_get_keyiv(struct sshcipher_ctx * cc,u_char * iv,u_int len)528 cipher_get_keyiv(struct sshcipher_ctx *cc, u_char *iv, u_int len)
529 {
530 const struct sshcipher *c = cc->cipher;
531 #ifdef WITH_OPENSSL
532 int evplen;
533 #endif
534
535 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
536 if (len != 0)
537 return SSH_ERR_INVALID_ARGUMENT;
538 return 0;
539 }
540 if ((cc->cipher->flags & CFLAG_AESCTR) != 0) {
541 if (len != sizeof(cc->ac_ctx.ctr))
542 return SSH_ERR_INVALID_ARGUMENT;
543 memcpy(iv, cc->ac_ctx.ctr, len);
544 return 0;
545 }
546 if ((cc->cipher->flags & CFLAG_NONE) != 0)
547 return 0;
548
549 switch (c->number) {
550 #ifdef WITH_OPENSSL
551 case SSH_CIPHER_SSH2:
552 case SSH_CIPHER_DES:
553 case SSH_CIPHER_BLOWFISH:
554 evplen = EVP_CIPHER_CTX_iv_length(cc->evp);
555 if (evplen == 0)
556 return 0;
557 else if (evplen < 0)
558 return SSH_ERR_LIBCRYPTO_ERROR;
559 if ((u_int)evplen != len)
560 return SSH_ERR_INVALID_ARGUMENT;
561 #ifndef OPENSSL_HAVE_EVPCTR
562 if (c->evptype == evp_aes_128_ctr)
563 ssh_aes_ctr_iv(cc->evp, 0, iv, len);
564 else
565 #endif
566 if (cipher_authlen(c)) {
567 if (!EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_IV_GEN,
568 len, iv))
569 return SSH_ERR_LIBCRYPTO_ERROR;
570 } else
571 memcpy(iv, EVP_CIPHER_CTX_iv(cc->evp), len);
572 break;
573 #endif
574 #ifdef WITH_SSH1
575 case SSH_CIPHER_3DES:
576 return ssh1_3des_iv(cc->evp, 0, iv, 24);
577 #endif
578 default:
579 return SSH_ERR_INVALID_ARGUMENT;
580 }
581 return 0;
582 }
583
584 int
cipher_set_keyiv(struct sshcipher_ctx * cc,const u_char * iv)585 cipher_set_keyiv(struct sshcipher_ctx *cc, const u_char *iv)
586 {
587 const struct sshcipher *c = cc->cipher;
588 #ifdef WITH_OPENSSL
589 int evplen = 0;
590 #endif
591
592 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
593 return 0;
594 if ((cc->cipher->flags & CFLAG_NONE) != 0)
595 return 0;
596
597 switch (c->number) {
598 #ifdef WITH_OPENSSL
599 case SSH_CIPHER_SSH2:
600 case SSH_CIPHER_DES:
601 case SSH_CIPHER_BLOWFISH:
602 evplen = EVP_CIPHER_CTX_iv_length(cc->evp);
603 if (evplen <= 0)
604 return SSH_ERR_LIBCRYPTO_ERROR;
605 if (cipher_authlen(c)) {
606 /* XXX iv arg is const, but EVP_CIPHER_CTX_ctrl isn't */
607 if (!EVP_CIPHER_CTX_ctrl(cc->evp,
608 EVP_CTRL_GCM_SET_IV_FIXED, -1, (void *)iv))
609 return SSH_ERR_LIBCRYPTO_ERROR;
610 } else {
611 /* XXX There must be a saner way to do this
612 than using the "getter" function to determine
613 the target of a copy operation */
614 memcpy(EVP_CIPHER_CTX_iv_noconst(cc->evp), iv, evplen);
615 }
616 break;
617 #endif
618 #ifdef WITH_SSH1
619 case SSH_CIPHER_3DES:
620 return ssh1_3des_iv(cc->evp, 1, (u_char *)iv, 24);
621 #endif
622 default:
623 return SSH_ERR_INVALID_ARGUMENT;
624 }
625 return 0;
626 }
627
628 #ifdef WITH_OPENSSL
629 #define EVP_X_STATE(evp) EVP_CIPHER_CTX_get_cipher_data(evp)
630 #define EVP_X_STATE_LEN(evp) EVP_CIPHER_impl_ctx_size(EVP_CIPHER_CTX_cipher(evp))
631 #endif
632
633 int
cipher_get_keycontext(const struct sshcipher_ctx * cc,u_char * dat)634 cipher_get_keycontext(const struct sshcipher_ctx *cc, u_char *dat)
635 {
636 #ifdef WITH_OPENSSL
637 const struct sshcipher *c = cc->cipher;
638 int plen = 0;
639
640 if (c->evptype == EVP_rc4) {
641 plen = EVP_X_STATE_LEN(cc->evp);
642 if (dat == NULL)
643 return (plen);
644 memcpy(dat, EVP_X_STATE(cc->evp), plen);
645 }
646 return (plen);
647 #else
648 return 0;
649 #endif
650 }
651
652 void
cipher_set_keycontext(struct sshcipher_ctx * cc,const u_char * dat)653 cipher_set_keycontext(struct sshcipher_ctx *cc, const u_char *dat)
654 {
655 #ifdef WITH_OPENSSL
656 const struct sshcipher *c = cc->cipher;
657 int plen;
658
659 if (c->evptype == EVP_rc4) {
660 plen = EVP_X_STATE_LEN(cc->evp);
661 memcpy(EVP_X_STATE(cc->evp), dat, plen);
662 }
663 #endif
664 }
665