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 1.68 2004/01/23 19:26:33 hshoexer 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 */
77 const EVP_CIPHER *(*evptype)(void);
79 { "none", SSH_CIPHER_NONE, 8, 0, EVP_enc_null },
80 { "des", SSH_CIPHER_DES, 8, 8, EVP_des_cbc },
81 { "3des", SSH_CIPHER_3DES, 8, 16, evp_ssh1_3des },
82 { "blowfish", SSH_CIPHER_BLOWFISH, 8, 32, evp_ssh1_bf },
84 { "3des-cbc", SSH_CIPHER_SSH2, 8, 24, EVP_des_ede3_cbc },
85 { "blowfish-cbc", SSH_CIPHER_SSH2, 8, 16, EVP_bf_cbc },
86 { "cast128-cbc", SSH_CIPHER_SSH2, 8, 16, EVP_cast5_cbc },
87 { "arcfour", SSH_CIPHER_SSH2, 8, 16, EVP_rc4 },
88 #if OPENSSL_VERSION_NUMBER < 0x00907000L
89 { "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, evp_rijndael },
90 { "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, evp_rijndael },
91 { "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, evp_rijndael },
92 { "rijndael-cbc@lysator.liu.se",
93 SSH_CIPHER_SSH2, 16, 32, evp_rijndael },
95 { "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, EVP_aes_128_cbc },
96 { "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, EVP_aes_192_cbc },
97 { "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, EVP_aes_256_cbc },
98 { "rijndael-cbc@lysator.liu.se",
99 SSH_CIPHER_SSH2, 16, 32, EVP_aes_256_cbc },
101 #if OPENSSL_VERSION_NUMBER >= 0x00905000L
102 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, evp_aes_128_ctr },
103 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, evp_aes_128_ctr },
104 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, evp_aes_128_ctr },
106 #if defined(EVP_CTRL_SET_ACSS_MODE)
107 { "acss@openssh.org", SSH_CIPHER_SSH2, 16, 5, EVP_acss },
109 { NULL, SSH_CIPHER_ILLEGAL, 0, 0, NULL }
115 cipher_blocksize(const Cipher *c)
117 return (c->block_size);
121 cipher_keylen(const Cipher *c)
127 cipher_get_number(const Cipher *c)
133 cipher_mask_ssh1(int client)
136 mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */
137 mask |= 1 << SSH_CIPHER_BLOWFISH;
139 mask |= 1 << SSH_CIPHER_DES;
145 cipher_by_name(const char *name)
148 for (c = ciphers; c->name != NULL; c++)
149 if (strcasecmp(c->name, name) == 0)
155 cipher_by_number(int id)
158 for (c = ciphers; c->name != NULL; c++)
164 #define CIPHER_SEP ","
166 ciphers_valid(const char *names)
172 if (names == NULL || strcmp(names, "") == 0)
174 ciphers = cp = xstrdup(names);
175 for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
176 (p = strsep(&cp, CIPHER_SEP))) {
177 c = cipher_by_name(p);
178 if (c == NULL || c->number != SSH_CIPHER_SSH2) {
179 debug("bad cipher %s [%s]", p, names);
183 debug3("cipher ok: %s [%s]", p, names);
186 debug3("ciphers ok: [%s]", names);
192 * Parses the name of the cipher. Returns the number of the corresponding
193 * cipher, or -1 on error.
197 cipher_number(const char *name)
202 c = cipher_by_name(name);
203 return (c==NULL) ? -1 : c->number;
209 Cipher *c = cipher_by_number(id);
210 return (c==NULL) ? "<unknown>" : c->name;
214 cipher_init(CipherContext *cc, Cipher *cipher,
215 const u_char *key, u_int keylen, const u_char *iv, u_int ivlen,
218 static int dowarn = 1;
222 const EVP_CIPHER *type;
226 if (cipher->number == SSH_CIPHER_DES) {
228 error("Warning: use of DES is strongly discouraged "
229 "due to cryptographic weaknesses");
235 cc->plaintext = (cipher->number == SSH_CIPHER_NONE);
237 if (keylen < cipher->key_len)
238 fatal("cipher_init: key length %d is insufficient for %s.",
239 keylen, cipher->name);
240 if (iv != NULL && ivlen < cipher->block_size)
241 fatal("cipher_init: iv length %d is insufficient for %s.",
242 ivlen, cipher->name);
245 type = (*cipher->evptype)();
247 EVP_CIPHER_CTX_init(&cc->evp);
249 if (type->key_len > 0 && type->key_len != keylen) {
250 debug("cipher_init: set keylen (%d -> %d)",
251 type->key_len, keylen);
252 type->key_len = keylen;
254 EVP_CipherInit(&cc->evp, type, (u_char *)key, (u_char *)iv,
255 (encrypt == CIPHER_ENCRYPT));
257 if (EVP_CipherInit(&cc->evp, type, NULL, (u_char *)iv,
258 (encrypt == CIPHER_ENCRYPT)) == 0)
259 fatal("cipher_init: EVP_CipherInit failed for %s",
261 klen = EVP_CIPHER_CTX_key_length(&cc->evp);
262 if (klen > 0 && keylen != klen) {
263 debug2("cipher_init: set keylen (%d -> %d)", klen, keylen);
264 if (EVP_CIPHER_CTX_set_key_length(&cc->evp, keylen) == 0)
265 fatal("cipher_init: set keylen failed (%d -> %d)",
268 if (EVP_CipherInit(&cc->evp, NULL, (u_char *)key, NULL, -1) == 0)
269 fatal("cipher_init: EVP_CipherInit: set key failed for %s",
275 cipher_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
277 if (len % cc->cipher->block_size)
278 fatal("cipher_encrypt: bad plaintext length %d", len);
280 EVP_Cipher(&cc->evp, dest, (u_char *)src, len);
282 if (EVP_Cipher(&cc->evp, dest, (u_char *)src, len) == 0)
283 fatal("evp_crypt: EVP_Cipher failed");
288 cipher_cleanup(CipherContext *cc)
291 EVP_CIPHER_CTX_cleanup(&cc->evp);
293 if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0)
294 error("cipher_cleanup: EVP_CIPHER_CTX_cleanup failed");
299 * Selects the cipher, and keys if by computing the MD5 checksum of the
300 * passphrase and using the resulting 16 bytes as the key.
304 cipher_set_key_string(CipherContext *cc, Cipher *cipher,
305 const char *passphrase, int encrypt)
311 MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase));
312 MD5_Final(digest, &md);
314 cipher_init(cc, cipher, digest, 16, NULL, 0, encrypt);
316 memset(digest, 0, sizeof(digest));
317 memset(&md, 0, sizeof(md));
321 * Exports an IV from the CipherContext required to export the key
322 * state back from the unprivileged child to the privileged parent
327 cipher_get_keyiv_len(const CipherContext *cc)
329 Cipher *c = cc->cipher;
332 if (c->number == SSH_CIPHER_3DES)
335 ivlen = EVP_CIPHER_CTX_iv_length(&cc->evp);
340 cipher_get_keyiv(CipherContext *cc, u_char *iv, u_int len)
342 Cipher *c = cc->cipher;
346 case SSH_CIPHER_SSH2:
348 case SSH_CIPHER_BLOWFISH:
349 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
353 fatal("%s: wrong iv length %d != %d", __func__,
355 #if OPENSSL_VERSION_NUMBER < 0x00907000L
356 if (c->evptype == evp_rijndael)
357 ssh_rijndael_iv(&cc->evp, 0, iv, len);
360 if (c->evptype == evp_aes_128_ctr)
361 ssh_aes_ctr_iv(&cc->evp, 0, iv, len);
363 memcpy(iv, cc->evp.iv, len);
365 case SSH_CIPHER_3DES:
366 ssh1_3des_iv(&cc->evp, 0, iv, 24);
369 fatal("%s: bad cipher %d", __func__, c->number);
374 cipher_set_keyiv(CipherContext *cc, u_char *iv)
376 Cipher *c = cc->cipher;
380 case SSH_CIPHER_SSH2:
382 case SSH_CIPHER_BLOWFISH:
383 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
386 #if OPENSSL_VERSION_NUMBER < 0x00907000L
387 if (c->evptype == evp_rijndael)
388 ssh_rijndael_iv(&cc->evp, 1, iv, evplen);
391 if (c->evptype == evp_aes_128_ctr)
392 ssh_aes_ctr_iv(&cc->evp, 1, iv, evplen);
394 memcpy(cc->evp.iv, iv, evplen);
396 case SSH_CIPHER_3DES:
397 ssh1_3des_iv(&cc->evp, 1, iv, 24);
400 fatal("%s: bad cipher %d", __func__, c->number);
404 #if OPENSSL_VERSION_NUMBER < 0x00907000L
405 #define EVP_X_STATE(evp) &(evp).c
406 #define EVP_X_STATE_LEN(evp) sizeof((evp).c)
408 #define EVP_X_STATE(evp) (evp).cipher_data
409 #define EVP_X_STATE_LEN(evp) (evp).cipher->ctx_size
413 cipher_get_keycontext(const CipherContext *cc, u_char *dat)
415 Cipher *c = cc->cipher;
418 if (c->evptype == EVP_rc4 || c->evptype == EVP_acss) {
419 plen = EVP_X_STATE_LEN(cc->evp);
422 memcpy(dat, EVP_X_STATE(cc->evp), plen);
428 cipher_set_keycontext(CipherContext *cc, u_char *dat)
430 Cipher *c = cc->cipher;
433 if (c->evptype == EVP_rc4 || c->evptype == EVP_acss) {
434 plen = EVP_X_STATE_LEN(cc->evp);
435 memcpy(EVP_X_STATE(cc->evp), dat, plen);