2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * 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".
13 * Copyright (c) 1999 Niels Provos. All rights reserved.
14 * Copyright (c) 1999, 2000 Markus Friedl. All rights reserved.
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
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.
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.
38 RCSID("$OpenBSD: cipher.c,v 1.74 2005/05/23 23:32:46 djm Exp $");
44 #include <openssl/md5.h>
46 #if OPENSSL_VERSION_NUMBER < 0x00906000L
48 #define EVP_CIPHER_CTX_get_app_data(e) ((e)->app_data)
51 #if OPENSSL_VERSION_NUMBER < 0x00907000L
52 extern const EVP_CIPHER *evp_rijndael(void);
53 extern void ssh_rijndael_iv(EVP_CIPHER_CTX *, int, u_char *, u_int);
56 #if !defined(EVP_CTRL_SET_ACSS_MODE)
57 # if (OPENSSL_VERSION_NUMBER >= 0x00907000L)
58 extern const EVP_CIPHER *evp_acss(void);
59 # define EVP_acss evp_acss
60 # define EVP_CTRL_SET_ACSS_MODE xxx /* used below */
62 # define EVP_acss NULL /* Don't try to support ACSS on older OpenSSL */
63 # endif /* (OPENSSL_VERSION_NUMBER >= 0x00906000L) */
64 #endif /* !defined(EVP_CTRL_SET_ACSS_MODE) */
66 extern const EVP_CIPHER *evp_ssh1_bf(void);
67 extern const EVP_CIPHER *evp_ssh1_3des(void);
68 extern void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
69 extern const EVP_CIPHER *evp_aes_128_ctr(void);
70 extern void ssh_aes_ctr_iv(EVP_CIPHER_CTX *, int, u_char *, u_int);
74 int number; /* for ssh1 only */
78 const EVP_CIPHER *(*evptype)(void);
80 { "none", SSH_CIPHER_NONE, 8, 0, 0, EVP_enc_null },
81 { "des", SSH_CIPHER_DES, 8, 8, 0, EVP_des_cbc },
82 { "3des", SSH_CIPHER_3DES, 8, 16, 0, evp_ssh1_3des },
83 { "blowfish", SSH_CIPHER_BLOWFISH, 8, 32, 0, evp_ssh1_bf },
85 { "3des-cbc", SSH_CIPHER_SSH2, 8, 24, 0, EVP_des_ede3_cbc },
86 { "blowfish-cbc", SSH_CIPHER_SSH2, 8, 16, 0, EVP_bf_cbc },
87 { "cast128-cbc", SSH_CIPHER_SSH2, 8, 16, 0, EVP_cast5_cbc },
88 { "arcfour", SSH_CIPHER_SSH2, 8, 16, 0, EVP_rc4 },
89 { "arcfour128", SSH_CIPHER_SSH2, 8, 16, 1536, EVP_rc4 },
90 { "arcfour256", SSH_CIPHER_SSH2, 8, 32, 1536, EVP_rc4 },
91 #if OPENSSL_VERSION_NUMBER < 0x00907000L
92 { "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, 0, evp_rijndael },
93 { "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, 0, evp_rijndael },
94 { "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, 0, evp_rijndael },
95 { "rijndael-cbc@lysator.liu.se",
96 SSH_CIPHER_SSH2, 16, 32, 0, evp_rijndael },
98 { "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, 0, EVP_aes_128_cbc },
99 { "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, 0, EVP_aes_192_cbc },
100 { "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, 0, EVP_aes_256_cbc },
101 { "rijndael-cbc@lysator.liu.se",
102 SSH_CIPHER_SSH2, 16, 32, 0, EVP_aes_256_cbc },
104 #if OPENSSL_VERSION_NUMBER >= 0x00905000L
105 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, evp_aes_128_ctr },
106 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, evp_aes_128_ctr },
107 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, evp_aes_128_ctr },
109 #if defined(EVP_CTRL_SET_ACSS_MODE)
110 { "acss@openssh.org", SSH_CIPHER_SSH2, 16, 5, 0, EVP_acss },
112 { NULL, SSH_CIPHER_INVALID, 0, 0, 0, NULL }
118 cipher_blocksize(const Cipher *c)
120 return (c->block_size);
124 cipher_keylen(const Cipher *c)
130 cipher_get_number(const Cipher *c)
136 cipher_mask_ssh1(int client)
139 mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */
140 mask |= 1 << SSH_CIPHER_BLOWFISH;
142 mask |= 1 << SSH_CIPHER_DES;
148 cipher_by_name(const char *name)
151 for (c = ciphers; c->name != NULL; c++)
152 if (strcmp(c->name, name) == 0)
158 cipher_by_number(int id)
161 for (c = ciphers; c->name != NULL; c++)
167 #define CIPHER_SEP ","
169 ciphers_valid(const char *names)
172 char *cipher_list, *cp;
175 if (names == NULL || strcmp(names, "") == 0)
177 cipher_list = cp = xstrdup(names);
178 for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
179 (p = strsep(&cp, CIPHER_SEP))) {
180 c = cipher_by_name(p);
181 if (c == NULL || c->number != SSH_CIPHER_SSH2) {
182 debug("bad cipher %s [%s]", p, names);
186 debug3("cipher ok: %s [%s]", p, names);
189 debug3("ciphers ok: [%s]", names);
195 * Parses the name of the cipher. Returns the number of the corresponding
196 * cipher, or -1 on error.
200 cipher_number(const char *name)
205 for (c = ciphers; c->name != NULL; c++)
206 if (strcasecmp(c->name, name) == 0)
214 Cipher *c = cipher_by_number(id);
215 return (c==NULL) ? "<unknown>" : c->name;
219 cipher_init(CipherContext *cc, Cipher *cipher,
220 const u_char *key, u_int keylen, const u_char *iv, u_int ivlen,
223 static int dowarn = 1;
227 const EVP_CIPHER *type;
230 u_char *junk, *discard;
232 if (cipher->number == SSH_CIPHER_DES) {
234 error("Warning: use of DES is strongly discouraged "
235 "due to cryptographic weaknesses");
241 cc->plaintext = (cipher->number == SSH_CIPHER_NONE);
243 if (keylen < cipher->key_len)
244 fatal("cipher_init: key length %d is insufficient for %s.",
245 keylen, cipher->name);
246 if (iv != NULL && ivlen < cipher->block_size)
247 fatal("cipher_init: iv length %d is insufficient for %s.",
248 ivlen, cipher->name);
251 type = (*cipher->evptype)();
253 EVP_CIPHER_CTX_init(&cc->evp);
255 if (type->key_len > 0 && type->key_len != keylen) {
256 debug("cipher_init: set keylen (%d -> %d)",
257 type->key_len, keylen);
258 type->key_len = keylen;
260 EVP_CipherInit(&cc->evp, type, (u_char *)key, (u_char *)iv,
261 (do_encrypt == CIPHER_ENCRYPT));
263 if (EVP_CipherInit(&cc->evp, type, NULL, (u_char *)iv,
264 (do_encrypt == CIPHER_ENCRYPT)) == 0)
265 fatal("cipher_init: EVP_CipherInit failed for %s",
267 klen = EVP_CIPHER_CTX_key_length(&cc->evp);
268 if (klen > 0 && keylen != klen) {
269 debug2("cipher_init: set keylen (%d -> %d)", klen, keylen);
270 if (EVP_CIPHER_CTX_set_key_length(&cc->evp, keylen) == 0)
271 fatal("cipher_init: set keylen failed (%d -> %d)",
274 if (EVP_CipherInit(&cc->evp, NULL, (u_char *)key, NULL, -1) == 0)
275 fatal("cipher_init: EVP_CipherInit: set key failed for %s",
279 if (cipher->discard_len > 0) {
280 junk = xmalloc(cipher->discard_len);
281 discard = xmalloc(cipher->discard_len);
282 if (EVP_Cipher(&cc->evp, discard, junk,
283 cipher->discard_len) == 0)
284 fatal("evp_crypt: EVP_Cipher failed during discard");
285 memset(discard, 0, cipher->discard_len);
292 cipher_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
294 if (len % cc->cipher->block_size)
295 fatal("cipher_encrypt: bad plaintext length %d", len);
297 EVP_Cipher(&cc->evp, dest, (u_char *)src, len);
299 if (EVP_Cipher(&cc->evp, dest, (u_char *)src, len) == 0)
300 fatal("evp_crypt: EVP_Cipher failed");
305 cipher_cleanup(CipherContext *cc)
308 EVP_CIPHER_CTX_cleanup(&cc->evp);
310 if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0)
311 error("cipher_cleanup: EVP_CIPHER_CTX_cleanup failed");
316 * Selects the cipher, and keys if by computing the MD5 checksum of the
317 * passphrase and using the resulting 16 bytes as the key.
321 cipher_set_key_string(CipherContext *cc, Cipher *cipher,
322 const char *passphrase, int do_encrypt)
328 MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase));
329 MD5_Final(digest, &md);
331 cipher_init(cc, cipher, digest, 16, NULL, 0, do_encrypt);
333 memset(digest, 0, sizeof(digest));
334 memset(&md, 0, sizeof(md));
338 * Exports an IV from the CipherContext required to export the key
339 * state back from the unprivileged child to the privileged parent
344 cipher_get_keyiv_len(const CipherContext *cc)
346 Cipher *c = cc->cipher;
349 if (c->number == SSH_CIPHER_3DES)
352 ivlen = EVP_CIPHER_CTX_iv_length(&cc->evp);
357 cipher_get_keyiv(CipherContext *cc, u_char *iv, u_int len)
359 Cipher *c = cc->cipher;
363 case SSH_CIPHER_SSH2:
365 case SSH_CIPHER_BLOWFISH:
366 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
370 fatal("%s: wrong iv length %d != %d", __func__,
372 #if OPENSSL_VERSION_NUMBER < 0x00907000L
373 if (c->evptype == evp_rijndael)
374 ssh_rijndael_iv(&cc->evp, 0, iv, len);
377 if (c->evptype == evp_aes_128_ctr)
378 ssh_aes_ctr_iv(&cc->evp, 0, iv, len);
380 memcpy(iv, cc->evp.iv, len);
382 case SSH_CIPHER_3DES:
383 ssh1_3des_iv(&cc->evp, 0, iv, 24);
386 fatal("%s: bad cipher %d", __func__, c->number);
391 cipher_set_keyiv(CipherContext *cc, u_char *iv)
393 Cipher *c = cc->cipher;
397 case SSH_CIPHER_SSH2:
399 case SSH_CIPHER_BLOWFISH:
400 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
403 #if OPENSSL_VERSION_NUMBER < 0x00907000L
404 if (c->evptype == evp_rijndael)
405 ssh_rijndael_iv(&cc->evp, 1, iv, evplen);
408 if (c->evptype == evp_aes_128_ctr)
409 ssh_aes_ctr_iv(&cc->evp, 1, iv, evplen);
411 memcpy(cc->evp.iv, iv, evplen);
413 case SSH_CIPHER_3DES:
414 ssh1_3des_iv(&cc->evp, 1, iv, 24);
417 fatal("%s: bad cipher %d", __func__, c->number);
421 #if OPENSSL_VERSION_NUMBER < 0x00907000L
422 #define EVP_X_STATE(evp) &(evp).c
423 #define EVP_X_STATE_LEN(evp) sizeof((evp).c)
425 #define EVP_X_STATE(evp) (evp).cipher_data
426 #define EVP_X_STATE_LEN(evp) (evp).cipher->ctx_size
430 cipher_get_keycontext(const CipherContext *cc, u_char *dat)
432 Cipher *c = cc->cipher;
435 if (c->evptype == EVP_rc4 || c->evptype == EVP_acss) {
436 plen = EVP_X_STATE_LEN(cc->evp);
439 memcpy(dat, EVP_X_STATE(cc->evp), plen);
445 cipher_set_keycontext(CipherContext *cc, u_char *dat)
447 Cipher *c = cc->cipher;
450 if (c->evptype == EVP_rc4 || c->evptype == EVP_acss) {
451 plen = EVP_X_STATE_LEN(cc->evp);
452 memcpy(EVP_X_STATE(cc->evp), dat, plen);