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 1.77 2005/07/16 01:35:24 djm Exp $");
44 #include <openssl/md5.h>
46 /* compatibility with old or broken OpenSSL versions */
47 #include "openbsd-compat/openssl-compat.h"
49 extern const EVP_CIPHER *evp_ssh1_bf(void);
50 extern const EVP_CIPHER *evp_ssh1_3des(void);
51 extern void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
52 extern const EVP_CIPHER *evp_aes_128_ctr(void);
53 extern void ssh_aes_ctr_iv(EVP_CIPHER_CTX *, int, u_char *, u_int);
57 int number; /* for ssh1 only */
61 const EVP_CIPHER *(*evptype)(void);
63 { "none", SSH_CIPHER_NONE, 8, 0, 0, EVP_enc_null },
64 { "des", SSH_CIPHER_DES, 8, 8, 0, EVP_des_cbc },
65 { "3des", SSH_CIPHER_3DES, 8, 16, 0, evp_ssh1_3des },
66 { "blowfish", SSH_CIPHER_BLOWFISH, 8, 32, 0, evp_ssh1_bf },
68 { "3des-cbc", SSH_CIPHER_SSH2, 8, 24, 0, EVP_des_ede3_cbc },
69 { "blowfish-cbc", SSH_CIPHER_SSH2, 8, 16, 0, EVP_bf_cbc },
70 { "cast128-cbc", SSH_CIPHER_SSH2, 8, 16, 0, EVP_cast5_cbc },
71 { "arcfour", SSH_CIPHER_SSH2, 8, 16, 0, EVP_rc4 },
72 { "arcfour128", SSH_CIPHER_SSH2, 8, 16, 1536, EVP_rc4 },
73 { "arcfour256", SSH_CIPHER_SSH2, 8, 32, 1536, EVP_rc4 },
74 { "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, 0, EVP_aes_128_cbc },
75 { "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, 0, EVP_aes_192_cbc },
76 { "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, 0, EVP_aes_256_cbc },
77 { "rijndael-cbc@lysator.liu.se",
78 SSH_CIPHER_SSH2, 16, 32, 0, EVP_aes_256_cbc },
79 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, evp_aes_128_ctr },
80 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, evp_aes_128_ctr },
81 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, evp_aes_128_ctr },
82 #ifdef USE_CIPHER_ACSS
83 { "acss@openssh.org", SSH_CIPHER_SSH2, 16, 5, 0, EVP_acss },
85 { NULL, SSH_CIPHER_INVALID, 0, 0, 0, NULL }
91 cipher_blocksize(const Cipher *c)
93 return (c->block_size);
97 cipher_keylen(const Cipher *c)
103 cipher_get_number(const Cipher *c)
109 cipher_mask_ssh1(int client)
112 mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */
113 mask |= 1 << SSH_CIPHER_BLOWFISH;
115 mask |= 1 << SSH_CIPHER_DES;
121 cipher_by_name(const char *name)
124 for (c = ciphers; c->name != NULL; c++)
125 if (strcmp(c->name, name) == 0)
131 cipher_by_number(int id)
134 for (c = ciphers; c->name != NULL; c++)
140 #define CIPHER_SEP ","
142 ciphers_valid(const char *names)
145 char *cipher_list, *cp;
148 if (names == NULL || strcmp(names, "") == 0)
150 cipher_list = cp = xstrdup(names);
151 for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
152 (p = strsep(&cp, CIPHER_SEP))) {
153 c = cipher_by_name(p);
154 if (c == NULL || c->number != SSH_CIPHER_SSH2) {
155 debug("bad cipher %s [%s]", p, names);
159 debug3("cipher ok: %s [%s]", p, names);
162 debug3("ciphers ok: [%s]", names);
168 * Parses the name of the cipher. Returns the number of the corresponding
169 * cipher, or -1 on error.
173 cipher_number(const char *name)
178 for (c = ciphers; c->name != NULL; c++)
179 if (strcasecmp(c->name, name) == 0)
187 Cipher *c = cipher_by_number(id);
188 return (c==NULL) ? "<unknown>" : c->name;
192 cipher_init(CipherContext *cc, Cipher *cipher,
193 const u_char *key, u_int keylen, const u_char *iv, u_int ivlen,
196 static int dowarn = 1;
200 const EVP_CIPHER *type;
203 u_char *junk, *discard;
205 if (cipher->number == SSH_CIPHER_DES) {
207 error("Warning: use of DES is strongly discouraged "
208 "due to cryptographic weaknesses");
214 cc->plaintext = (cipher->number == SSH_CIPHER_NONE);
216 if (keylen < cipher->key_len)
217 fatal("cipher_init: key length %d is insufficient for %s.",
218 keylen, cipher->name);
219 if (iv != NULL && ivlen < cipher->block_size)
220 fatal("cipher_init: iv length %d is insufficient for %s.",
221 ivlen, cipher->name);
224 type = (*cipher->evptype)();
226 EVP_CIPHER_CTX_init(&cc->evp);
228 if (type->key_len > 0 && type->key_len != keylen) {
229 debug("cipher_init: set keylen (%d -> %d)",
230 type->key_len, keylen);
231 type->key_len = keylen;
233 EVP_CipherInit(&cc->evp, type, (u_char *)key, (u_char *)iv,
234 (do_encrypt == CIPHER_ENCRYPT));
236 if (EVP_CipherInit(&cc->evp, type, NULL, (u_char *)iv,
237 (do_encrypt == CIPHER_ENCRYPT)) == 0)
238 fatal("cipher_init: EVP_CipherInit failed for %s",
240 klen = EVP_CIPHER_CTX_key_length(&cc->evp);
241 if (klen > 0 && keylen != (u_int)klen) {
242 debug2("cipher_init: set keylen (%d -> %d)", klen, keylen);
243 if (EVP_CIPHER_CTX_set_key_length(&cc->evp, keylen) == 0)
244 fatal("cipher_init: set keylen failed (%d -> %d)",
247 if (EVP_CipherInit(&cc->evp, NULL, (u_char *)key, NULL, -1) == 0)
248 fatal("cipher_init: EVP_CipherInit: set key failed for %s",
252 if (cipher->discard_len > 0) {
253 junk = xmalloc(cipher->discard_len);
254 discard = xmalloc(cipher->discard_len);
255 if (EVP_Cipher(&cc->evp, discard, junk,
256 cipher->discard_len) == 0)
257 fatal("evp_crypt: EVP_Cipher failed during discard");
258 memset(discard, 0, cipher->discard_len);
265 cipher_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
267 if (len % cc->cipher->block_size)
268 fatal("cipher_encrypt: bad plaintext length %d", len);
269 if (EVP_Cipher(&cc->evp, dest, (u_char *)src, len) == 0)
270 fatal("evp_crypt: EVP_Cipher failed");
274 cipher_cleanup(CipherContext *cc)
276 if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0)
277 error("cipher_cleanup: EVP_CIPHER_CTX_cleanup failed");
281 * Selects the cipher, and keys if by computing the MD5 checksum of the
282 * passphrase and using the resulting 16 bytes as the key.
286 cipher_set_key_string(CipherContext *cc, Cipher *cipher,
287 const char *passphrase, int do_encrypt)
293 MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase));
294 MD5_Final(digest, &md);
296 cipher_init(cc, cipher, digest, 16, NULL, 0, do_encrypt);
298 memset(digest, 0, sizeof(digest));
299 memset(&md, 0, sizeof(md));
303 * Exports an IV from the CipherContext required to export the key
304 * state back from the unprivileged child to the privileged parent
309 cipher_get_keyiv_len(const CipherContext *cc)
311 Cipher *c = cc->cipher;
314 if (c->number == SSH_CIPHER_3DES)
317 ivlen = EVP_CIPHER_CTX_iv_length(&cc->evp);
322 cipher_get_keyiv(CipherContext *cc, u_char *iv, u_int len)
324 Cipher *c = cc->cipher;
328 case SSH_CIPHER_SSH2:
330 case SSH_CIPHER_BLOWFISH:
331 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
334 if ((u_int)evplen != len)
335 fatal("%s: wrong iv length %d != %d", __func__,
337 #if OPENSSL_VERSION_NUMBER < 0x00907000L
338 if (c->evptype == evp_rijndael)
339 ssh_rijndael_iv(&cc->evp, 0, iv, len);
342 if (c->evptype == evp_aes_128_ctr)
343 ssh_aes_ctr_iv(&cc->evp, 0, iv, len);
345 memcpy(iv, cc->evp.iv, len);
347 case SSH_CIPHER_3DES:
348 ssh1_3des_iv(&cc->evp, 0, iv, 24);
351 fatal("%s: bad cipher %d", __func__, c->number);
356 cipher_set_keyiv(CipherContext *cc, u_char *iv)
358 Cipher *c = cc->cipher;
362 case SSH_CIPHER_SSH2:
364 case SSH_CIPHER_BLOWFISH:
365 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
368 #if OPENSSL_VERSION_NUMBER < 0x00907000L
369 if (c->evptype == evp_rijndael)
370 ssh_rijndael_iv(&cc->evp, 1, iv, evplen);
373 if (c->evptype == evp_aes_128_ctr)
374 ssh_aes_ctr_iv(&cc->evp, 1, iv, evplen);
376 memcpy(cc->evp.iv, iv, evplen);
378 case SSH_CIPHER_3DES:
379 ssh1_3des_iv(&cc->evp, 1, iv, 24);
382 fatal("%s: bad cipher %d", __func__, c->number);
386 #if OPENSSL_VERSION_NUMBER < 0x00907000L
387 #define EVP_X_STATE(evp) &(evp).c
388 #define EVP_X_STATE_LEN(evp) sizeof((evp).c)
390 #define EVP_X_STATE(evp) (evp).cipher_data
391 #define EVP_X_STATE_LEN(evp) (evp).cipher->ctx_size
395 cipher_get_keycontext(const CipherContext *cc, u_char *dat)
397 Cipher *c = cc->cipher;
400 if (c->evptype == EVP_rc4 || c->evptype == EVP_acss) {
401 plen = EVP_X_STATE_LEN(cc->evp);
404 memcpy(dat, EVP_X_STATE(cc->evp), plen);
410 cipher_set_keycontext(CipherContext *cc, u_char *dat)
412 Cipher *c = cc->cipher;
415 if (c->evptype == EVP_rc4 || c->evptype == EVP_acss) {
416 plen = EVP_X_STATE_LEN(cc->evp);
417 memcpy(EVP_X_STATE(cc->evp), dat, plen);