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 1.64 2003/05/15 03:08:29 markus 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);
55 extern const EVP_CIPHER *evp_ssh1_bf(void);
56 extern const EVP_CIPHER *evp_ssh1_3des(void);
57 extern void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
61 int number; /* for ssh1 only */
64 const EVP_CIPHER *(*evptype)(void);
66 { "none", SSH_CIPHER_NONE, 8, 0, EVP_enc_null },
67 { "des", SSH_CIPHER_DES, 8, 8, EVP_des_cbc },
68 { "3des", SSH_CIPHER_3DES, 8, 16, evp_ssh1_3des },
69 { "blowfish", SSH_CIPHER_BLOWFISH, 8, 32, evp_ssh1_bf },
71 { "3des-cbc", SSH_CIPHER_SSH2, 8, 24, EVP_des_ede3_cbc },
72 { "blowfish-cbc", SSH_CIPHER_SSH2, 8, 16, EVP_bf_cbc },
73 { "cast128-cbc", SSH_CIPHER_SSH2, 8, 16, EVP_cast5_cbc },
74 { "arcfour", SSH_CIPHER_SSH2, 8, 16, EVP_rc4 },
75 #if OPENSSL_VERSION_NUMBER < 0x00907000L
76 { "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, evp_rijndael },
77 { "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, evp_rijndael },
78 { "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, evp_rijndael },
79 { "rijndael-cbc@lysator.liu.se",
80 SSH_CIPHER_SSH2, 16, 32, evp_rijndael },
82 { "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, EVP_aes_128_cbc },
83 { "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, EVP_aes_192_cbc },
84 { "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, EVP_aes_256_cbc },
85 { "rijndael-cbc@lysator.liu.se",
86 SSH_CIPHER_SSH2, 16, 32, EVP_aes_256_cbc },
89 { NULL, SSH_CIPHER_ILLEGAL, 0, 0, NULL }
95 cipher_blocksize(Cipher *c)
97 return (c->block_size);
101 cipher_keylen(Cipher *c)
107 cipher_get_number(Cipher *c)
113 cipher_mask_ssh1(int client)
116 mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */
117 mask |= 1 << SSH_CIPHER_BLOWFISH;
119 mask |= 1 << SSH_CIPHER_DES;
125 cipher_by_name(const char *name)
128 for (c = ciphers; c->name != NULL; c++)
129 if (strcasecmp(c->name, name) == 0)
135 cipher_by_number(int id)
138 for (c = ciphers; c->name != NULL; c++)
144 #define CIPHER_SEP ","
146 ciphers_valid(const char *names)
152 if (names == NULL || strcmp(names, "") == 0)
154 ciphers = cp = xstrdup(names);
155 for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
156 (p = strsep(&cp, CIPHER_SEP))) {
157 c = cipher_by_name(p);
158 if (c == NULL || c->number != SSH_CIPHER_SSH2) {
159 debug("bad cipher %s [%s]", p, names);
163 debug3("cipher ok: %s [%s]", p, names);
166 debug3("ciphers ok: [%s]", names);
172 * Parses the name of the cipher. Returns the number of the corresponding
173 * cipher, or -1 on error.
177 cipher_number(const char *name)
182 c = cipher_by_name(name);
183 return (c==NULL) ? -1 : c->number;
189 Cipher *c = cipher_by_number(id);
190 return (c==NULL) ? "<unknown>" : c->name;
194 cipher_init(CipherContext *cc, Cipher *cipher,
195 const u_char *key, u_int keylen, const u_char *iv, u_int ivlen,
198 static int dowarn = 1;
202 const EVP_CIPHER *type;
206 if (cipher->number == SSH_CIPHER_DES) {
208 error("Warning: use of DES is strongly discouraged "
209 "due to cryptographic weaknesses");
215 cc->plaintext = (cipher->number == SSH_CIPHER_NONE);
217 if (keylen < cipher->key_len)
218 fatal("cipher_init: key length %d is insufficient for %s.",
219 keylen, cipher->name);
220 if (iv != NULL && ivlen < cipher->block_size)
221 fatal("cipher_init: iv length %d is insufficient for %s.",
222 ivlen, cipher->name);
225 type = (*cipher->evptype)();
227 EVP_CIPHER_CTX_init(&cc->evp);
229 if (type->key_len > 0 && type->key_len != keylen) {
230 debug("cipher_init: set keylen (%d -> %d)",
231 type->key_len, keylen);
232 type->key_len = keylen;
234 EVP_CipherInit(&cc->evp, type, (u_char *)key, (u_char *)iv,
235 (encrypt == CIPHER_ENCRYPT));
237 if (EVP_CipherInit(&cc->evp, type, NULL, (u_char *)iv,
238 (encrypt == CIPHER_ENCRYPT)) == 0)
239 fatal("cipher_init: EVP_CipherInit failed for %s",
241 klen = EVP_CIPHER_CTX_key_length(&cc->evp);
242 if (klen > 0 && keylen != klen) {
243 debug2("cipher_init: set keylen (%d -> %d)", klen, keylen);
244 if (EVP_CIPHER_CTX_set_key_length(&cc->evp, keylen) == 0)
245 fatal("cipher_init: set keylen failed (%d -> %d)",
248 if (EVP_CipherInit(&cc->evp, NULL, (u_char *)key, NULL, -1) == 0)
249 fatal("cipher_init: EVP_CipherInit: set key failed for %s",
255 cipher_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
257 if (len % cc->cipher->block_size)
258 fatal("cipher_encrypt: bad plaintext length %d", len);
260 EVP_Cipher(&cc->evp, dest, (u_char *)src, len);
262 if (EVP_Cipher(&cc->evp, dest, (u_char *)src, len) == 0)
263 fatal("evp_crypt: EVP_Cipher failed");
268 cipher_cleanup(CipherContext *cc)
271 EVP_CIPHER_CTX_cleanup(&cc->evp);
273 if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0)
274 error("cipher_cleanup: EVP_CIPHER_CTX_cleanup failed");
279 * Selects the cipher, and keys if by computing the MD5 checksum of the
280 * passphrase and using the resulting 16 bytes as the key.
284 cipher_set_key_string(CipherContext *cc, Cipher *cipher,
285 const char *passphrase, int encrypt)
291 MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase));
292 MD5_Final(digest, &md);
294 cipher_init(cc, cipher, digest, 16, NULL, 0, encrypt);
296 memset(digest, 0, sizeof(digest));
297 memset(&md, 0, sizeof(md));
301 * Exports an IV from the CipherContext required to export the key
302 * state back from the unprivileged child to the privileged parent
307 cipher_get_keyiv_len(CipherContext *cc)
309 Cipher *c = cc->cipher;
312 if (c->number == SSH_CIPHER_3DES)
315 ivlen = EVP_CIPHER_CTX_iv_length(&cc->evp);
320 cipher_get_keyiv(CipherContext *cc, u_char *iv, u_int len)
322 Cipher *c = cc->cipher;
326 case SSH_CIPHER_SSH2:
328 case SSH_CIPHER_BLOWFISH:
329 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
333 fatal("%s: wrong iv length %d != %d", __func__,
335 #if OPENSSL_VERSION_NUMBER < 0x00907000L
336 if (c->evptype == evp_rijndael)
337 ssh_rijndael_iv(&cc->evp, 0, iv, len);
340 memcpy(iv, cc->evp.iv, len);
342 case SSH_CIPHER_3DES:
343 ssh1_3des_iv(&cc->evp, 0, iv, 24);
346 fatal("%s: bad cipher %d", __func__, c->number);
351 cipher_set_keyiv(CipherContext *cc, u_char *iv)
353 Cipher *c = cc->cipher;
357 case SSH_CIPHER_SSH2:
359 case SSH_CIPHER_BLOWFISH:
360 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
363 #if OPENSSL_VERSION_NUMBER < 0x00907000L
364 if (c->evptype == evp_rijndael)
365 ssh_rijndael_iv(&cc->evp, 1, iv, evplen);
368 memcpy(cc->evp.iv, iv, evplen);
370 case SSH_CIPHER_3DES:
371 ssh1_3des_iv(&cc->evp, 1, iv, 24);
374 fatal("%s: bad cipher %d", __func__, c->number);
378 #if OPENSSL_VERSION_NUMBER < 0x00907000L
379 #define EVP_X_STATE(evp) &(evp).c
380 #define EVP_X_STATE_LEN(evp) sizeof((evp).c)
382 #define EVP_X_STATE(evp) (evp).cipher_data
383 #define EVP_X_STATE_LEN(evp) (evp).cipher->ctx_size
387 cipher_get_keycontext(CipherContext *cc, u_char *dat)
389 Cipher *c = cc->cipher;
392 if (c->evptype == EVP_rc4) {
393 plen = EVP_X_STATE_LEN(cc->evp);
396 memcpy(dat, EVP_X_STATE(cc->evp), plen);
402 cipher_set_keycontext(CipherContext *cc, u_char *dat)
404 Cipher *c = cc->cipher;
407 if (c->evptype == EVP_rc4) {
408 plen = EVP_X_STATE_LEN(cc->evp);
409 memcpy(EVP_X_STATE(cc->evp), dat, plen);