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 1.39 2000/12/06 23:05:42 markus Exp $");
43 #include <openssl/md5.h>
48 none_setkey(CipherContext *cc, const u_char *key, u_int keylen)
52 none_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
56 none_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
58 memcpy(dest, src, len);
63 des_ssh1_setkey(CipherContext *cc, const u_char *key, u_int keylen)
65 static int dowarn = 1;
67 error("Warning: use of DES is strongly discouraged "
68 "due to cryptographic weaknesses");
71 des_set_key((void *)key, cc->u.des.key);
74 des_ssh1_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
76 memset(cc->u.des.iv, 0, sizeof(cc->u.des.iv));
79 des_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
81 des_ncbc_encrypt(src, dest, len, cc->u.des.key, &cc->u.des.iv,
85 des_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
87 des_ncbc_encrypt(src, dest, len, cc->u.des.key, &cc->u.des.iv,
93 des3_setkey(CipherContext *cc, const u_char *key, u_int keylen)
95 des_set_key((void *) key, cc->u.des3.key1);
96 des_set_key((void *) (key+8), cc->u.des3.key2);
97 des_set_key((void *) (key+16), cc->u.des3.key3);
100 des3_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
102 memset(cc->u.des3.iv2, 0, sizeof(cc->u.des3.iv2));
103 memset(cc->u.des3.iv3, 0, sizeof(cc->u.des3.iv3));
106 memcpy(cc->u.des3.iv3, (char *)iv, 8);
109 des3_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
111 des_ede3_cbc_encrypt(src, dest, len,
112 cc->u.des3.key1, cc->u.des3.key2, cc->u.des3.key3,
113 &cc->u.des3.iv3, DES_ENCRYPT);
116 des3_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
118 des_ede3_cbc_encrypt(src, dest, len,
119 cc->u.des3.key1, cc->u.des3.key2, cc->u.des3.key3,
120 &cc->u.des3.iv3, DES_DECRYPT);
124 * This is used by SSH1:
126 * What kind of triple DES are these 2 routines?
128 * Why is there a redundant initialization vector?
130 * If only iv3 was used, then, this would till effect have been
131 * outer-cbc. However, there is also a private iv1 == iv2 which
132 * perhaps makes differential analysis easier. On the other hand, the
133 * private iv1 probably makes the CRC-32 attack ineffective. This is a
134 * result of that there is no longer any known iv1 to use when
135 * choosing the X block.
138 des3_ssh1_setkey(CipherContext *cc, const u_char *key, u_int keylen)
140 des_set_key((void *) key, cc->u.des3.key1);
141 des_set_key((void *) (key+8), cc->u.des3.key2);
143 des_set_key((void *) key, cc->u.des3.key3);
145 des_set_key((void *) (key+16), cc->u.des3.key3);
148 des3_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
152 des_cblock *iv2 = &cc->u.des3.iv2;
153 des_cblock *iv3 = &cc->u.des3.iv3;
155 memcpy(&iv1, iv2, 8);
157 des_ncbc_encrypt(src, dest, len, cc->u.des3.key1, &iv1, DES_ENCRYPT);
158 des_ncbc_encrypt(dest, dest, len, cc->u.des3.key2, iv2, DES_DECRYPT);
159 des_ncbc_encrypt(dest, dest, len, cc->u.des3.key3, iv3, DES_ENCRYPT);
162 des3_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
166 des_cblock *iv2 = &cc->u.des3.iv2;
167 des_cblock *iv3 = &cc->u.des3.iv3;
169 memcpy(&iv1, iv2, 8);
171 des_ncbc_encrypt(src, dest, len, cc->u.des3.key3, iv3, DES_DECRYPT);
172 des_ncbc_encrypt(dest, dest, len, cc->u.des3.key2, iv2, DES_ENCRYPT);
173 des_ncbc_encrypt(dest, dest, len, cc->u.des3.key1, &iv1, DES_DECRYPT);
178 blowfish_setkey(CipherContext *cc, const u_char *key, u_int keylen)
180 BF_set_key(&cc->u.bf.key, keylen, (unsigned char *)key);
183 blowfish_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
186 memset(cc->u.bf.iv, 0, 8);
188 memcpy(cc->u.bf.iv, (char *)iv, 8);
191 blowfish_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
194 BF_cbc_encrypt((void *)src, dest, len, &cc->u.bf.key, cc->u.bf.iv,
198 blowfish_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
201 BF_cbc_encrypt((void *)src, dest, len, &cc->u.bf.key, cc->u.bf.iv,
206 * SSH1 uses a variation on Blowfish, all bytes must be swapped before
207 * and after encryption/decryption. Thus the swap_bytes stuff (yuk).
210 swap_bytes(const unsigned char *src, unsigned char *dst, int n)
214 /* Process 4 bytes every lap. */
215 for (n = n / 4; n > 0; n--) {
229 blowfish_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
232 swap_bytes(src, dest, len);
233 BF_cbc_encrypt((void *)dest, dest, len, &cc->u.bf.key, cc->u.bf.iv,
235 swap_bytes(dest, dest, len);
238 blowfish_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
241 swap_bytes(src, dest, len);
242 BF_cbc_encrypt((void *)dest, dest, len, &cc->u.bf.key, cc->u.bf.iv,
244 swap_bytes(dest, dest, len);
249 arcfour_setkey(CipherContext *cc, const u_char *key, u_int keylen)
251 RC4_set_key(&cc->u.rc4, keylen, (u_char *)key);
254 arcfour_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
256 RC4(&cc->u.rc4, len, (u_char *)src, dest);
261 cast_setkey(CipherContext *cc, const u_char *key, u_int keylen)
263 CAST_set_key(&cc->u.cast.key, keylen, (unsigned char *) key);
266 cast_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
269 fatal("no IV for %s.", cc->cipher->name);
270 memcpy(cc->u.cast.iv, (char *)iv, 8);
273 cast_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
275 CAST_cbc_encrypt(src, dest, len, &cc->u.cast.key, cc->u.cast.iv,
279 cast_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
281 CAST_cbc_encrypt(src, dest, len, &cc->u.cast.key, cc->u.cast.iv,
287 #define RIJNDAEL_BLOCKSIZE 16
290 rijndael_setkey(CipherContext *cc, const u_char *key, u_int keylen)
292 if (rijndael_makekey(&cc->u.rijndael.enc, RIJNDAEL_ENCRYPT,
293 8*keylen, (char *)key) == -1)
294 fatal("rijndael_setkey: RIJNDAEL_ENCRYPT");
295 if (rijndael_makekey(&cc->u.rijndael.dec, RIJNDAEL_DECRYPT,
296 8*keylen, (char *)key) == -1)
297 fatal("rijndael_setkey: RIJNDAEL_DECRYPT");
300 rijndael_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
302 if (iv == NULL || ivlen != RIJNDAEL_BLOCKSIZE)
303 fatal("bad/no IV for %s.", cc->cipher->name);
304 memcpy(cc->u.rijndael.iv, iv, RIJNDAEL_BLOCKSIZE);
308 rijndael_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
311 rijndael_key *ctx = &cc->u.rijndael.enc;
312 u_char *iv = cc->u.rijndael.iv;
313 u_char in[RIJNDAEL_BLOCKSIZE];
314 u_char *cprev, *cnow, *plain;
315 int i, j, blocks = len / RIJNDAEL_BLOCKSIZE;
318 if (len % RIJNDAEL_BLOCKSIZE)
319 fatal("rijndael_cbc_encrypt: bad len %d", len);
321 plain = (u_char *) src;
323 for(i = 0; i < blocks; i++, plain+=RIJNDAEL_BLOCKSIZE,
324 cnow+=RIJNDAEL_BLOCKSIZE) {
325 for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
326 in[j] = plain[j] ^ cprev[j];
327 rijndael_encrypt(ctx, in, cnow);
330 memcpy(iv, cprev, RIJNDAEL_BLOCKSIZE);
334 rijndael_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
337 rijndael_key *ctx = &cc->u.rijndael.dec;
338 u_char *iv = cc->u.rijndael.iv;
339 u_char ivsaved[RIJNDAEL_BLOCKSIZE];
340 u_char *cnow = (u_char *) (src+len-RIJNDAEL_BLOCKSIZE);
341 u_char *plain = dest+len-RIJNDAEL_BLOCKSIZE;
343 int i, j, blocks = len / RIJNDAEL_BLOCKSIZE;
346 if (len % RIJNDAEL_BLOCKSIZE)
347 fatal("rijndael_cbc_decrypt: bad len %d", len);
348 memcpy(ivsaved, cnow, RIJNDAEL_BLOCKSIZE);
349 for(i = blocks; i > 0; i--, cnow-=RIJNDAEL_BLOCKSIZE,
350 plain-=RIJNDAEL_BLOCKSIZE) {
351 rijndael_decrypt(ctx, cnow, plain);
352 //rijndael_decrypt(cnow, plain, ctx->keySched, ctx->ROUNDS);
353 ivp = (i == 1) ? iv : cnow-RIJNDAEL_BLOCKSIZE;
354 for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
357 memcpy(iv, ivsaved, RIJNDAEL_BLOCKSIZE);
362 SSH_CIPHER_NONE, 8, 0,
363 none_setkey, none_setiv,
364 none_crypt, none_crypt },
366 SSH_CIPHER_DES, 8, 8,
367 des_ssh1_setkey, des_ssh1_setiv,
368 des_ssh1_encrypt, des_ssh1_decrypt },
370 SSH_CIPHER_3DES, 8, 16,
371 des3_ssh1_setkey, des3_setiv,
372 des3_ssh1_encrypt, des3_ssh1_decrypt },
374 SSH_CIPHER_BLOWFISH, 8, 16,
375 blowfish_setkey, blowfish_setiv,
376 blowfish_ssh1_encrypt, blowfish_ssh1_decrypt },
379 SSH_CIPHER_SSH2, 8, 24,
380 des3_setkey, des3_setiv,
381 des3_cbc_encrypt, des3_cbc_decrypt },
383 SSH_CIPHER_SSH2, 8, 16,
384 blowfish_setkey, blowfish_setiv,
385 blowfish_cbc_encrypt, blowfish_cbc_decrypt },
387 SSH_CIPHER_SSH2, 8, 16,
388 cast_setkey, cast_setiv,
389 cast_cbc_encrypt, cast_cbc_decrypt },
391 SSH_CIPHER_SSH2, 8, 16,
392 arcfour_setkey, none_setiv,
393 arcfour_crypt, arcfour_crypt },
395 SSH_CIPHER_SSH2, 16, 16,
396 rijndael_setkey, rijndael_setiv,
397 rijndael_cbc_encrypt, rijndael_cbc_decrypt },
399 SSH_CIPHER_SSH2, 16, 24,
400 rijndael_setkey, rijndael_setiv,
401 rijndael_cbc_encrypt, rijndael_cbc_decrypt },
403 SSH_CIPHER_SSH2, 16, 32,
404 rijndael_setkey, rijndael_setiv,
405 rijndael_cbc_encrypt, rijndael_cbc_decrypt },
407 SSH_CIPHER_SSH2, 16, 16,
408 rijndael_setkey, rijndael_setiv,
409 rijndael_cbc_encrypt, rijndael_cbc_decrypt },
411 SSH_CIPHER_SSH2, 16, 24,
412 rijndael_setkey, rijndael_setiv,
413 rijndael_cbc_encrypt, rijndael_cbc_decrypt },
415 SSH_CIPHER_SSH2, 16, 32,
416 rijndael_setkey, rijndael_setiv,
417 rijndael_cbc_encrypt, rijndael_cbc_decrypt },
418 { "rijndael-cbc@lysator.liu.se",
419 SSH_CIPHER_SSH2, 16, 32,
420 rijndael_setkey, rijndael_setiv,
421 rijndael_cbc_encrypt, rijndael_cbc_decrypt },
422 { NULL, SSH_CIPHER_ILLEGAL, 0, 0, NULL, NULL, NULL, NULL }
428 cipher_mask_ssh1(int client)
430 unsigned int mask = 0;
431 mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */
432 mask |= 1 << SSH_CIPHER_BLOWFISH;
434 mask |= 1 << SSH_CIPHER_DES;
440 cipher_by_name(const char *name)
443 for (c = ciphers; c->name != NULL; c++)
444 if (strcasecmp(c->name, name) == 0)
450 cipher_by_number(int id)
453 for (c = ciphers; c->name != NULL; c++)
459 #define CIPHER_SEP ","
461 ciphers_valid(const char *names)
467 if (names == NULL || strcmp(names, "") == 0)
469 ciphers = cp = xstrdup(names);
470 for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
471 (p = strsep(&cp, CIPHER_SEP))) {
472 c = cipher_by_name(p);
473 if (c == NULL || c->number != SSH_CIPHER_SSH2) {
474 debug("bad cipher %s [%s]", p, names);
478 debug3("cipher ok: %s [%s]", p, names);
481 debug3("ciphers ok: [%s]", names);
487 * Parses the name of the cipher. Returns the number of the corresponding
488 * cipher, or -1 on error.
492 cipher_number(const char *name)
497 c = cipher_by_name(name);
498 return (c==NULL) ? -1 : c->number;
504 Cipher *c = cipher_by_number(id);
505 return (c==NULL) ? "<unknown>" : c->name;
509 cipher_init(CipherContext *cc, Cipher *cipher,
510 const u_char *key, u_int keylen, const u_char *iv, u_int ivlen)
512 if (keylen < cipher->key_len)
513 fatal("cipher_init: key length %d is insufficient for %s.",
514 keylen, cipher->name);
515 if (iv != NULL && ivlen < cipher->block_size)
516 fatal("cipher_init: iv length %d is insufficient for %s.",
517 ivlen, cipher->name);
519 cipher->setkey(cc, key, keylen);
520 cipher->setiv(cc, iv, ivlen);
524 cipher_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
526 if (len % cc->cipher->block_size)
527 fatal("cipher_encrypt: bad plaintext length %d", len);
528 cc->cipher->encrypt(cc, dest, src, len);
532 cipher_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
534 if (len % cc->cipher->block_size)
535 fatal("cipher_decrypt: bad ciphertext length %d", len);
536 cc->cipher->decrypt(cc, dest, src, len);
540 * Selects the cipher, and keys if by computing the MD5 checksum of the
541 * passphrase and using the resulting 16 bytes as the key.
545 cipher_set_key_string(CipherContext *cc, Cipher *cipher,
546 const char *passphrase)
549 unsigned char digest[16];
552 MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase));
553 MD5_Final(digest, &md);
555 cipher_init(cc, cipher, digest, 16, NULL, 0);
557 memset(digest, 0, sizeof(digest));
558 memset(&md, 0, sizeof(md));