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 "openbsd-compat/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 #if !defined(ANDROID)
89 { "3des-cbc", SSH_CIPHER_SSH2, 8, 24, 0, 0, 0, 1, EVP_des_ede3_cbc },
90 { "blowfish-cbc",
91 SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 1, EVP_bf_cbc },
92 { "cast128-cbc",
93 SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 1, EVP_cast5_cbc },
94 #endif
95 { "arcfour", SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 0, EVP_rc4 },
96 { "arcfour128", SSH_CIPHER_SSH2, 8, 16, 0, 0, 1536, 0, EVP_rc4 },
97 { "arcfour256", SSH_CIPHER_SSH2, 8, 32, 0, 0, 1536, 0, EVP_rc4 },
98 { "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, 1, EVP_aes_128_cbc },
99 { "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, 1, EVP_aes_192_cbc },
100 { "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 1, EVP_aes_256_cbc },
101 { "rijndael-cbc@lysator.liu.se",
102 SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 1, EVP_aes_256_cbc },
103 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, 0, EVP_aes_128_ctr },
104 #if !defined(ANDROID)
105 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, 0, EVP_aes_192_ctr },
106 #endif
107 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 0, EVP_aes_256_ctr },
108 # ifdef OPENSSL_HAVE_EVPGCM
109 { "aes128-gcm@openssh.com",
110 SSH_CIPHER_SSH2, 16, 16, 12, 16, 0, 0, EVP_aes_128_gcm },
111 { "aes256-gcm@openssh.com",
112 SSH_CIPHER_SSH2, 16, 32, 12, 16, 0, 0, EVP_aes_256_gcm },
113 # endif /* OPENSSL_HAVE_EVPGCM */
114 #else /* WITH_OPENSSL */
115 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, CFLAG_AESCTR, NULL },
116 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, CFLAG_AESCTR, NULL },
117 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, CFLAG_AESCTR, NULL },
118 { "none", SSH_CIPHER_NONE, 8, 0, 0, 0, 0, CFLAG_NONE, NULL },
119 #endif /* WITH_OPENSSL */
120 { "chacha20-poly1305@openssh.com",
121 SSH_CIPHER_SSH2, 8, 64, 0, 16, 0, CFLAG_CHACHAPOLY, NULL },
122
123 { NULL, SSH_CIPHER_INVALID, 0, 0, 0, 0, 0, 0, NULL }
124 };
125
126 /*--*/
127
128 /* Returns a comma-separated list of supported ciphers. */
129 char *
cipher_alg_list(char sep,int auth_only)130 cipher_alg_list(char sep, int auth_only)
131 {
132 char *tmp, *ret = NULL;
133 size_t nlen, rlen = 0;
134 const struct sshcipher *c;
135
136 for (c = ciphers; c->name != NULL; c++) {
137 if (c->number != SSH_CIPHER_SSH2)
138 continue;
139 if (auth_only && c->auth_len == 0)
140 continue;
141 if (ret != NULL)
142 ret[rlen++] = sep;
143 nlen = strlen(c->name);
144 if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) {
145 free(ret);
146 return NULL;
147 }
148 ret = tmp;
149 memcpy(ret + rlen, c->name, nlen + 1);
150 rlen += nlen;
151 }
152 return ret;
153 }
154
155 u_int
cipher_blocksize(const struct sshcipher * c)156 cipher_blocksize(const struct sshcipher *c)
157 {
158 return (c->block_size);
159 }
160
161 u_int
cipher_keylen(const struct sshcipher * c)162 cipher_keylen(const struct sshcipher *c)
163 {
164 return (c->key_len);
165 }
166
167 u_int
cipher_seclen(const struct sshcipher * c)168 cipher_seclen(const struct sshcipher *c)
169 {
170 if (strcmp("3des-cbc", c->name) == 0)
171 return 14;
172 return cipher_keylen(c);
173 }
174
175 u_int
cipher_authlen(const struct sshcipher * c)176 cipher_authlen(const struct sshcipher *c)
177 {
178 return (c->auth_len);
179 }
180
181 u_int
cipher_ivlen(const struct sshcipher * c)182 cipher_ivlen(const struct sshcipher *c)
183 {
184 /*
185 * Default is cipher block size, except for chacha20+poly1305 that
186 * needs no IV. XXX make iv_len == -1 default?
187 */
188 return (c->iv_len != 0 || (c->flags & CFLAG_CHACHAPOLY) != 0) ?
189 c->iv_len : c->block_size;
190 }
191
192 u_int
cipher_get_number(const struct sshcipher * c)193 cipher_get_number(const struct sshcipher *c)
194 {
195 return (c->number);
196 }
197
198 u_int
cipher_is_cbc(const struct sshcipher * c)199 cipher_is_cbc(const struct sshcipher *c)
200 {
201 return (c->flags & CFLAG_CBC) != 0;
202 }
203
204 u_int
cipher_mask_ssh1(int client)205 cipher_mask_ssh1(int client)
206 {
207 u_int mask = 0;
208 mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */
209 mask |= 1 << SSH_CIPHER_BLOWFISH;
210 if (client) {
211 mask |= 1 << SSH_CIPHER_DES;
212 }
213 return mask;
214 }
215
216 const struct sshcipher *
cipher_by_name(const char * name)217 cipher_by_name(const char *name)
218 {
219 const struct sshcipher *c;
220 for (c = ciphers; c->name != NULL; c++)
221 if (strcmp(c->name, name) == 0)
222 return c;
223 return NULL;
224 }
225
226 const struct sshcipher *
cipher_by_number(int id)227 cipher_by_number(int id)
228 {
229 const struct sshcipher *c;
230 for (c = ciphers; c->name != NULL; c++)
231 if (c->number == id)
232 return c;
233 return NULL;
234 }
235
236 #define CIPHER_SEP ","
237 int
ciphers_valid(const char * names)238 ciphers_valid(const char *names)
239 {
240 const struct sshcipher *c;
241 char *cipher_list, *cp;
242 char *p;
243
244 if (names == NULL || strcmp(names, "") == 0)
245 return 0;
246 if ((cipher_list = cp = strdup(names)) == NULL)
247 return 0;
248 for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
249 (p = strsep(&cp, CIPHER_SEP))) {
250 c = cipher_by_name(p);
251 if (c == NULL || c->number != SSH_CIPHER_SSH2) {
252 free(cipher_list);
253 return 0;
254 }
255 }
256 free(cipher_list);
257 return 1;
258 }
259
260 /*
261 * Parses the name of the cipher. Returns the number of the corresponding
262 * cipher, or -1 on error.
263 */
264
265 int
cipher_number(const char * name)266 cipher_number(const char *name)
267 {
268 const struct sshcipher *c;
269 if (name == NULL)
270 return -1;
271 for (c = ciphers; c->name != NULL; c++)
272 if (strcasecmp(c->name, name) == 0)
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 EVP_CIPHER_CTX_init(&cc->evp);
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_cleanup(&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 else if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0)
477 return SSH_ERR_LIBCRYPTO_ERROR;
478 #endif
479 return 0;
480 }
481
482 /*
483 * Selects the cipher, and keys if by computing the MD5 checksum of the
484 * passphrase and using the resulting 16 bytes as the key.
485 */
486 int
cipher_set_key_string(struct sshcipher_ctx * cc,const struct sshcipher * cipher,const char * passphrase,int do_encrypt)487 cipher_set_key_string(struct sshcipher_ctx *cc, const struct sshcipher *cipher,
488 const char *passphrase, int do_encrypt)
489 {
490 u_char digest[16];
491 int r = SSH_ERR_INTERNAL_ERROR;
492
493 if ((r = ssh_digest_memory(SSH_DIGEST_MD5,
494 passphrase, strlen(passphrase),
495 digest, sizeof(digest))) != 0)
496 goto out;
497
498 r = cipher_init(cc, cipher, digest, 16, NULL, 0, do_encrypt);
499 out:
500 explicit_bzero(digest, sizeof(digest));
501 return r;
502 }
503
504 /*
505 * Exports an IV from the sshcipher_ctx required to export the key
506 * state back from the unprivileged child to the privileged parent
507 * process.
508 */
509 int
cipher_get_keyiv_len(const struct sshcipher_ctx * cc)510 cipher_get_keyiv_len(const struct sshcipher_ctx *cc)
511 {
512 const struct sshcipher *c = cc->cipher;
513 int ivlen = 0;
514
515 if (c->number == SSH_CIPHER_3DES)
516 ivlen = 24;
517 else if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
518 ivlen = 0;
519 else if ((cc->cipher->flags & CFLAG_AESCTR) != 0)
520 ivlen = sizeof(cc->ac_ctx.ctr);
521 #ifdef WITH_OPENSSL
522 else
523 ivlen = EVP_CIPHER_CTX_iv_length(&cc->evp);
524 #endif /* WITH_OPENSSL */
525 return (ivlen);
526 }
527
528 int
cipher_get_keyiv(struct sshcipher_ctx * cc,u_char * iv,u_int len)529 cipher_get_keyiv(struct sshcipher_ctx *cc, u_char *iv, u_int len)
530 {
531 const struct sshcipher *c = cc->cipher;
532 #ifdef WITH_OPENSSL
533 int evplen;
534 #endif
535
536 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
537 if (len != 0)
538 return SSH_ERR_INVALID_ARGUMENT;
539 return 0;
540 }
541 if ((cc->cipher->flags & CFLAG_AESCTR) != 0) {
542 if (len != sizeof(cc->ac_ctx.ctr))
543 return SSH_ERR_INVALID_ARGUMENT;
544 memcpy(iv, cc->ac_ctx.ctr, len);
545 return 0;
546 }
547 if ((cc->cipher->flags & CFLAG_NONE) != 0)
548 return 0;
549
550 switch (c->number) {
551 #ifdef WITH_OPENSSL
552 case SSH_CIPHER_SSH2:
553 case SSH_CIPHER_DES:
554 case SSH_CIPHER_BLOWFISH:
555 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
556 if (evplen == 0)
557 return 0;
558 else if (evplen < 0)
559 return SSH_ERR_LIBCRYPTO_ERROR;
560 if ((u_int)evplen != len)
561 return SSH_ERR_INVALID_ARGUMENT;
562 #ifndef OPENSSL_HAVE_EVPCTR
563 if (c->evptype == evp_aes_128_ctr)
564 ssh_aes_ctr_iv(&cc->evp, 0, iv, len);
565 else
566 #endif
567 if (cipher_authlen(c)) {
568 if (!EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_IV_GEN,
569 len, iv))
570 return SSH_ERR_LIBCRYPTO_ERROR;
571 } else
572 memcpy(iv, cc->evp.iv, len);
573 break;
574 #endif
575 #ifdef WITH_SSH1
576 case SSH_CIPHER_3DES:
577 return ssh1_3des_iv(&cc->evp, 0, iv, 24);
578 #endif
579 default:
580 return SSH_ERR_INVALID_ARGUMENT;
581 }
582 return 0;
583 }
584
585 int
cipher_set_keyiv(struct sshcipher_ctx * cc,const u_char * iv)586 cipher_set_keyiv(struct sshcipher_ctx *cc, const u_char *iv)
587 {
588 const struct sshcipher *c = cc->cipher;
589 #ifdef WITH_OPENSSL
590 int evplen = 0;
591 #endif
592
593 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
594 return 0;
595 if ((cc->cipher->flags & CFLAG_NONE) != 0)
596 return 0;
597
598 switch (c->number) {
599 #ifdef WITH_OPENSSL
600 case SSH_CIPHER_SSH2:
601 case SSH_CIPHER_DES:
602 case SSH_CIPHER_BLOWFISH:
603 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
604 if (evplen <= 0)
605 return SSH_ERR_LIBCRYPTO_ERROR;
606 if (cipher_authlen(c)) {
607 /* XXX iv arg is const, but EVP_CIPHER_CTX_ctrl isn't */
608 if (!EVP_CIPHER_CTX_ctrl(&cc->evp,
609 EVP_CTRL_GCM_SET_IV_FIXED, -1, (void *)iv))
610 return SSH_ERR_LIBCRYPTO_ERROR;
611 } else
612 memcpy(cc->evp.iv, iv, evplen);
613 break;
614 #endif
615 #ifdef WITH_SSH1
616 case SSH_CIPHER_3DES:
617 return ssh1_3des_iv(&cc->evp, 1, (u_char *)iv, 24);
618 #endif
619 default:
620 return SSH_ERR_INVALID_ARGUMENT;
621 }
622 return 0;
623 }
624
625 #ifdef WITH_OPENSSL
626 #define EVP_X_STATE(evp) (evp).cipher_data
627 #define EVP_X_STATE_LEN(evp) (evp).cipher->ctx_size
628 #endif
629
630 int
cipher_get_keycontext(const struct sshcipher_ctx * cc,u_char * dat)631 cipher_get_keycontext(const struct sshcipher_ctx *cc, u_char *dat)
632 {
633 #ifdef WITH_OPENSSL
634 const struct sshcipher *c = cc->cipher;
635 int plen = 0;
636
637 if (c->evptype == EVP_rc4) {
638 plen = EVP_X_STATE_LEN(cc->evp);
639 if (dat == NULL)
640 return (plen);
641 memcpy(dat, EVP_X_STATE(cc->evp), plen);
642 }
643 return (plen);
644 #else
645 return 0;
646 #endif
647 }
648
649 void
cipher_set_keycontext(struct sshcipher_ctx * cc,const u_char * dat)650 cipher_set_keycontext(struct sshcipher_ctx *cc, const u_char *dat)
651 {
652 #ifdef WITH_OPENSSL
653 const struct sshcipher *c = cc->cipher;
654 int plen;
655
656 if (c->evptype == EVP_rc4) {
657 plen = EVP_X_STATE_LEN(cc->evp);
658 memcpy(EVP_X_STATE(cc->evp), dat, plen);
659 }
660 #endif
661 }
662