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 1.65 2003/05/17 04:27:52 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);
58 extern const EVP_CIPHER *evp_aes_128_ctr(void);
59 extern void ssh_aes_ctr_iv(EVP_CIPHER_CTX *, int, u_char *, u_int);
63 int number; /* for ssh1 only */
66 const EVP_CIPHER *(*evptype)(void);
68 { "none", SSH_CIPHER_NONE, 8, 0, EVP_enc_null },
69 { "des", SSH_CIPHER_DES, 8, 8, EVP_des_cbc },
70 { "3des", SSH_CIPHER_3DES, 8, 16, evp_ssh1_3des },
71 { "blowfish", SSH_CIPHER_BLOWFISH, 8, 32, evp_ssh1_bf },
73 { "3des-cbc", SSH_CIPHER_SSH2, 8, 24, EVP_des_ede3_cbc },
74 { "blowfish-cbc", SSH_CIPHER_SSH2, 8, 16, EVP_bf_cbc },
75 { "cast128-cbc", SSH_CIPHER_SSH2, 8, 16, EVP_cast5_cbc },
76 { "arcfour", SSH_CIPHER_SSH2, 8, 16, EVP_rc4 },
77 #if OPENSSL_VERSION_NUMBER < 0x00907000L
78 { "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, evp_rijndael },
79 { "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, evp_rijndael },
80 { "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, evp_rijndael },
81 { "rijndael-cbc@lysator.liu.se",
82 SSH_CIPHER_SSH2, 16, 32, evp_rijndael },
84 { "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, EVP_aes_128_cbc },
85 { "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, EVP_aes_192_cbc },
86 { "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, EVP_aes_256_cbc },
87 { "rijndael-cbc@lysator.liu.se",
88 SSH_CIPHER_SSH2, 16, 32, EVP_aes_256_cbc },
90 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, evp_aes_128_ctr },
91 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, evp_aes_128_ctr },
92 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, evp_aes_128_ctr },
94 { NULL, SSH_CIPHER_ILLEGAL, 0, 0, NULL }
100 cipher_blocksize(Cipher *c)
102 return (c->block_size);
106 cipher_keylen(Cipher *c)
112 cipher_get_number(Cipher *c)
118 cipher_mask_ssh1(int client)
121 mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */
122 mask |= 1 << SSH_CIPHER_BLOWFISH;
124 mask |= 1 << SSH_CIPHER_DES;
130 cipher_by_name(const char *name)
133 for (c = ciphers; c->name != NULL; c++)
134 if (strcasecmp(c->name, name) == 0)
140 cipher_by_number(int id)
143 for (c = ciphers; c->name != NULL; c++)
149 #define CIPHER_SEP ","
151 ciphers_valid(const char *names)
157 if (names == NULL || strcmp(names, "") == 0)
159 ciphers = cp = xstrdup(names);
160 for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
161 (p = strsep(&cp, CIPHER_SEP))) {
162 c = cipher_by_name(p);
163 if (c == NULL || c->number != SSH_CIPHER_SSH2) {
164 debug("bad cipher %s [%s]", p, names);
168 debug3("cipher ok: %s [%s]", p, names);
171 debug3("ciphers ok: [%s]", names);
177 * Parses the name of the cipher. Returns the number of the corresponding
178 * cipher, or -1 on error.
182 cipher_number(const char *name)
187 c = cipher_by_name(name);
188 return (c==NULL) ? -1 : c->number;
194 Cipher *c = cipher_by_number(id);
195 return (c==NULL) ? "<unknown>" : c->name;
199 cipher_init(CipherContext *cc, Cipher *cipher,
200 const u_char *key, u_int keylen, const u_char *iv, u_int ivlen,
203 static int dowarn = 1;
207 const EVP_CIPHER *type;
211 if (cipher->number == SSH_CIPHER_DES) {
213 error("Warning: use of DES is strongly discouraged "
214 "due to cryptographic weaknesses");
220 cc->plaintext = (cipher->number == SSH_CIPHER_NONE);
222 if (keylen < cipher->key_len)
223 fatal("cipher_init: key length %d is insufficient for %s.",
224 keylen, cipher->name);
225 if (iv != NULL && ivlen < cipher->block_size)
226 fatal("cipher_init: iv length %d is insufficient for %s.",
227 ivlen, cipher->name);
230 type = (*cipher->evptype)();
232 EVP_CIPHER_CTX_init(&cc->evp);
234 if (type->key_len > 0 && type->key_len != keylen) {
235 debug("cipher_init: set keylen (%d -> %d)",
236 type->key_len, keylen);
237 type->key_len = keylen;
239 EVP_CipherInit(&cc->evp, type, (u_char *)key, (u_char *)iv,
240 (encrypt == CIPHER_ENCRYPT));
242 if (EVP_CipherInit(&cc->evp, type, NULL, (u_char *)iv,
243 (encrypt == CIPHER_ENCRYPT)) == 0)
244 fatal("cipher_init: EVP_CipherInit failed for %s",
246 klen = EVP_CIPHER_CTX_key_length(&cc->evp);
247 if (klen > 0 && keylen != klen) {
248 debug2("cipher_init: set keylen (%d -> %d)", klen, keylen);
249 if (EVP_CIPHER_CTX_set_key_length(&cc->evp, keylen) == 0)
250 fatal("cipher_init: set keylen failed (%d -> %d)",
253 if (EVP_CipherInit(&cc->evp, NULL, (u_char *)key, NULL, -1) == 0)
254 fatal("cipher_init: EVP_CipherInit: set key failed for %s",
260 cipher_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
262 if (len % cc->cipher->block_size)
263 fatal("cipher_encrypt: bad plaintext length %d", len);
265 EVP_Cipher(&cc->evp, dest, (u_char *)src, len);
267 if (EVP_Cipher(&cc->evp, dest, (u_char *)src, len) == 0)
268 fatal("evp_crypt: EVP_Cipher failed");
273 cipher_cleanup(CipherContext *cc)
276 EVP_CIPHER_CTX_cleanup(&cc->evp);
278 if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0)
279 error("cipher_cleanup: EVP_CIPHER_CTX_cleanup failed");
284 * Selects the cipher, and keys if by computing the MD5 checksum of the
285 * passphrase and using the resulting 16 bytes as the key.
289 cipher_set_key_string(CipherContext *cc, Cipher *cipher,
290 const char *passphrase, int encrypt)
296 MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase));
297 MD5_Final(digest, &md);
299 cipher_init(cc, cipher, digest, 16, NULL, 0, encrypt);
301 memset(digest, 0, sizeof(digest));
302 memset(&md, 0, sizeof(md));
306 * Exports an IV from the CipherContext required to export the key
307 * state back from the unprivileged child to the privileged parent
312 cipher_get_keyiv_len(CipherContext *cc)
314 Cipher *c = cc->cipher;
317 if (c->number == SSH_CIPHER_3DES)
320 ivlen = EVP_CIPHER_CTX_iv_length(&cc->evp);
325 cipher_get_keyiv(CipherContext *cc, u_char *iv, u_int len)
327 Cipher *c = cc->cipher;
331 case SSH_CIPHER_SSH2:
333 case SSH_CIPHER_BLOWFISH:
334 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
338 fatal("%s: wrong iv length %d != %d", __func__,
340 #if OPENSSL_VERSION_NUMBER < 0x00907000L
341 if (c->evptype == evp_rijndael)
342 ssh_rijndael_iv(&cc->evp, 0, iv, len);
345 if (c->evptype == evp_aes_128_ctr)
346 ssh_aes_ctr_iv(&cc->evp, 0, iv, len);
348 memcpy(iv, cc->evp.iv, len);
350 case SSH_CIPHER_3DES:
351 ssh1_3des_iv(&cc->evp, 0, iv, 24);
354 fatal("%s: bad cipher %d", __func__, c->number);
359 cipher_set_keyiv(CipherContext *cc, u_char *iv)
361 Cipher *c = cc->cipher;
365 case SSH_CIPHER_SSH2:
367 case SSH_CIPHER_BLOWFISH:
368 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
371 #if OPENSSL_VERSION_NUMBER < 0x00907000L
372 if (c->evptype == evp_rijndael)
373 ssh_rijndael_iv(&cc->evp, 1, iv, evplen);
376 if (c->evptype == evp_aes_128_ctr)
377 ssh_aes_ctr_iv(&cc->evp, 1, iv, evplen);
379 memcpy(cc->evp.iv, iv, evplen);
381 case SSH_CIPHER_3DES:
382 ssh1_3des_iv(&cc->evp, 1, iv, 24);
385 fatal("%s: bad cipher %d", __func__, c->number);
389 #if OPENSSL_VERSION_NUMBER < 0x00907000L
390 #define EVP_X_STATE(evp) &(evp).c
391 #define EVP_X_STATE_LEN(evp) sizeof((evp).c)
393 #define EVP_X_STATE(evp) (evp).cipher_data
394 #define EVP_X_STATE_LEN(evp) (evp).cipher->ctx_size
398 cipher_get_keycontext(CipherContext *cc, u_char *dat)
400 Cipher *c = cc->cipher;
403 if (c->evptype == EVP_rc4) {
404 plen = EVP_X_STATE_LEN(cc->evp);
407 memcpy(dat, EVP_X_STATE(cc->evp), plen);
413 cipher_set_keycontext(CipherContext *cc, u_char *dat)
415 Cipher *c = cc->cipher;
418 if (c->evptype == EVP_rc4) {
419 plen = EVP_X_STATE_LEN(cc->evp);
420 memcpy(EVP_X_STATE(cc->evp), dat, plen);