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 1.44 2001/05/28 22:51:10 markus Exp $");
44 #include <openssl/md5.h>
49 none_setkey(CipherContext *cc, const u_char *key, u_int keylen)
53 none_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
57 none_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
59 memcpy(dest, src, len);
64 des_ssh1_setkey(CipherContext *cc, const u_char *key, u_int keylen)
66 static int dowarn = 1;
68 error("Warning: use of DES is strongly discouraged "
69 "due to cryptographic weaknesses");
72 des_set_key((void *)key, cc->u.des.key);
75 des_ssh1_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
77 memset(cc->u.des.iv, 0, sizeof(cc->u.des.iv));
80 des_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
82 des_ncbc_encrypt(src, dest, len, cc->u.des.key, &cc->u.des.iv,
86 des_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
88 des_ncbc_encrypt(src, dest, len, cc->u.des.key, &cc->u.des.iv,
94 des3_setkey(CipherContext *cc, const u_char *key, u_int keylen)
96 des_set_key((void *) key, cc->u.des3.key1);
97 des_set_key((void *) (key+8), cc->u.des3.key2);
98 des_set_key((void *) (key+16), cc->u.des3.key3);
101 des3_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
103 memset(cc->u.des3.iv1, 0, sizeof(cc->u.des3.iv1));
104 memset(cc->u.des3.iv2, 0, sizeof(cc->u.des3.iv2));
105 memset(cc->u.des3.iv3, 0, sizeof(cc->u.des3.iv3));
108 memcpy(cc->u.des3.iv3, (char *)iv, 8);
111 des3_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
113 des_ede3_cbc_encrypt(src, dest, len,
114 cc->u.des3.key1, cc->u.des3.key2, cc->u.des3.key3,
115 &cc->u.des3.iv3, DES_ENCRYPT);
118 des3_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
120 des_ede3_cbc_encrypt(src, dest, len,
121 cc->u.des3.key1, cc->u.des3.key2, cc->u.des3.key3,
122 &cc->u.des3.iv3, DES_DECRYPT);
126 * This is used by SSH1:
128 * What kind of triple DES are these 2 routines?
130 * Why is there a redundant initialization vector?
132 * If only iv3 was used, then, this would till effect have been
133 * outer-cbc. However, there is also a private iv1 == iv2 which
134 * perhaps makes differential analysis easier. On the other hand, the
135 * private iv1 probably makes the CRC-32 attack ineffective. This is a
136 * result of that there is no longer any known iv1 to use when
137 * choosing the X block.
140 des3_ssh1_setkey(CipherContext *cc, const u_char *key, u_int keylen)
142 des_set_key((void *) key, cc->u.des3.key1);
143 des_set_key((void *) (key+8), cc->u.des3.key2);
145 des_set_key((void *) key, cc->u.des3.key3);
147 des_set_key((void *) (key+16), cc->u.des3.key3);
150 des3_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
153 des_ncbc_encrypt(src, dest, len, cc->u.des3.key1, &cc->u.des3.iv1,
155 des_ncbc_encrypt(dest, dest, len, cc->u.des3.key2, &cc->u.des3.iv2,
157 des_ncbc_encrypt(dest, dest, len, cc->u.des3.key3, &cc->u.des3.iv3,
161 des3_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
164 des_ncbc_encrypt(src, dest, len, cc->u.des3.key3, &cc->u.des3.iv3,
166 des_ncbc_encrypt(dest, dest, len, cc->u.des3.key2, &cc->u.des3.iv2,
168 des_ncbc_encrypt(dest, dest, len, cc->u.des3.key1, &cc->u.des3.iv1,
174 blowfish_setkey(CipherContext *cc, const u_char *key, u_int keylen)
176 BF_set_key(&cc->u.bf.key, keylen, (u_char *)key);
179 blowfish_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
182 memset(cc->u.bf.iv, 0, 8);
184 memcpy(cc->u.bf.iv, (char *)iv, 8);
187 blowfish_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
190 BF_cbc_encrypt((void *)src, dest, len, &cc->u.bf.key, cc->u.bf.iv,
194 blowfish_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
197 BF_cbc_encrypt((void *)src, dest, len, &cc->u.bf.key, cc->u.bf.iv,
202 * SSH1 uses a variation on Blowfish, all bytes must be swapped before
203 * and after encryption/decryption. Thus the swap_bytes stuff (yuk).
206 swap_bytes(const u_char *src, u_char *dst, int n)
210 /* Process 4 bytes every lap. */
211 for (n = n / 4; n > 0; n--) {
225 blowfish_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
228 swap_bytes(src, dest, len);
229 BF_cbc_encrypt((void *)dest, dest, len, &cc->u.bf.key, cc->u.bf.iv,
231 swap_bytes(dest, dest, len);
234 blowfish_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
237 swap_bytes(src, dest, len);
238 BF_cbc_encrypt((void *)dest, dest, len, &cc->u.bf.key, cc->u.bf.iv,
240 swap_bytes(dest, dest, len);
245 arcfour_setkey(CipherContext *cc, const u_char *key, u_int keylen)
247 RC4_set_key(&cc->u.rc4, keylen, (u_char *)key);
250 arcfour_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
252 RC4(&cc->u.rc4, len, (u_char *)src, dest);
257 cast_setkey(CipherContext *cc, const u_char *key, u_int keylen)
259 CAST_set_key(&cc->u.cast.key, keylen, (u_char *) key);
262 cast_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
265 fatal("no IV for %s.", cc->cipher->name);
266 memcpy(cc->u.cast.iv, (char *)iv, 8);
269 cast_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
271 CAST_cbc_encrypt(src, dest, len, &cc->u.cast.key, cc->u.cast.iv,
275 cast_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
277 CAST_cbc_encrypt(src, dest, len, &cc->u.cast.key, cc->u.cast.iv,
283 #define RIJNDAEL_BLOCKSIZE 16
285 rijndael_setkey(CipherContext *cc, const u_char *key, u_int keylen)
287 rijndael_set_key(&cc->u.rijndael.enc, (u4byte *)key, 8*keylen, 1);
288 rijndael_set_key(&cc->u.rijndael.dec, (u4byte *)key, 8*keylen, 0);
291 rijndael_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
294 fatal("no IV for %s.", cc->cipher->name);
295 memcpy((u_char *)cc->u.rijndael.iv, iv, RIJNDAEL_BLOCKSIZE);
298 rijndael_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
301 rijndael_ctx *ctx = &cc->u.rijndael.enc;
302 u4byte *iv = cc->u.rijndael.iv;
304 u4byte *cprev, *cnow, *plain;
305 int i, blocks = len / RIJNDAEL_BLOCKSIZE;
308 if (len % RIJNDAEL_BLOCKSIZE)
309 fatal("rijndael_cbc_encrypt: bad len %d", len);
310 cnow = (u4byte*) dest;
311 plain = (u4byte*) src;
313 for(i = 0; i < blocks; i++, plain+=4, cnow+=4) {
314 in[0] = plain[0] ^ cprev[0];
315 in[1] = plain[1] ^ cprev[1];
316 in[2] = plain[2] ^ cprev[2];
317 in[3] = plain[3] ^ cprev[3];
318 rijndael_encrypt(ctx, in, cnow);
321 memcpy(iv, cprev, RIJNDAEL_BLOCKSIZE);
325 rijndael_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
328 rijndael_ctx *ctx = &cc->u.rijndael.dec;
329 u4byte *iv = cc->u.rijndael.iv;
331 u4byte *cnow = (u4byte*) (src+len-RIJNDAEL_BLOCKSIZE);
332 u4byte *plain = (u4byte*) (dest+len-RIJNDAEL_BLOCKSIZE);
334 int i, blocks = len / RIJNDAEL_BLOCKSIZE;
337 if (len % RIJNDAEL_BLOCKSIZE)
338 fatal("rijndael_cbc_decrypt: bad len %d", len);
339 memcpy(ivsaved, cnow, RIJNDAEL_BLOCKSIZE);
340 for(i = blocks; i > 0; i--, cnow-=4, plain-=4) {
341 rijndael_decrypt(ctx, cnow, plain);
342 ivp = (i == 1) ? iv : cnow-4;
348 memcpy(iv, ivsaved, RIJNDAEL_BLOCKSIZE);
353 SSH_CIPHER_NONE, 8, 0,
354 none_setkey, none_setiv,
355 none_crypt, none_crypt },
357 SSH_CIPHER_DES, 8, 8,
358 des_ssh1_setkey, des_ssh1_setiv,
359 des_ssh1_encrypt, des_ssh1_decrypt },
361 SSH_CIPHER_3DES, 8, 16,
362 des3_ssh1_setkey, des3_setiv,
363 des3_ssh1_encrypt, des3_ssh1_decrypt },
365 SSH_CIPHER_BLOWFISH, 8, 16,
366 blowfish_setkey, blowfish_setiv,
367 blowfish_ssh1_encrypt, blowfish_ssh1_decrypt },
370 SSH_CIPHER_SSH2, 8, 24,
371 des3_setkey, des3_setiv,
372 des3_cbc_encrypt, des3_cbc_decrypt },
374 SSH_CIPHER_SSH2, 8, 16,
375 blowfish_setkey, blowfish_setiv,
376 blowfish_cbc_encrypt, blowfish_cbc_decrypt },
378 SSH_CIPHER_SSH2, 8, 16,
379 cast_setkey, cast_setiv,
380 cast_cbc_encrypt, cast_cbc_decrypt },
382 SSH_CIPHER_SSH2, 8, 16,
383 arcfour_setkey, none_setiv,
384 arcfour_crypt, arcfour_crypt },
386 SSH_CIPHER_SSH2, 16, 16,
387 rijndael_setkey, rijndael_setiv,
388 rijndael_cbc_encrypt, rijndael_cbc_decrypt },
390 SSH_CIPHER_SSH2, 16, 24,
391 rijndael_setkey, rijndael_setiv,
392 rijndael_cbc_encrypt, rijndael_cbc_decrypt },
394 SSH_CIPHER_SSH2, 16, 32,
395 rijndael_setkey, rijndael_setiv,
396 rijndael_cbc_encrypt, rijndael_cbc_decrypt },
398 SSH_CIPHER_SSH2, 16, 16,
399 rijndael_setkey, rijndael_setiv,
400 rijndael_cbc_encrypt, rijndael_cbc_decrypt },
402 SSH_CIPHER_SSH2, 16, 24,
403 rijndael_setkey, rijndael_setiv,
404 rijndael_cbc_encrypt, rijndael_cbc_decrypt },
406 SSH_CIPHER_SSH2, 16, 32,
407 rijndael_setkey, rijndael_setiv,
408 rijndael_cbc_encrypt, rijndael_cbc_decrypt },
409 { "rijndael-cbc@lysator.liu.se",
410 SSH_CIPHER_SSH2, 16, 32,
411 rijndael_setkey, rijndael_setiv,
412 rijndael_cbc_encrypt, rijndael_cbc_decrypt },
413 { NULL, SSH_CIPHER_ILLEGAL, 0, 0, NULL, NULL, NULL, NULL }
419 cipher_mask_ssh1(int client)
422 mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */
423 mask |= 1 << SSH_CIPHER_BLOWFISH;
425 mask |= 1 << SSH_CIPHER_DES;
431 cipher_by_name(const char *name)
434 for (c = ciphers; c->name != NULL; c++)
435 if (strcasecmp(c->name, name) == 0)
441 cipher_by_number(int id)
444 for (c = ciphers; c->name != NULL; c++)
450 #define CIPHER_SEP ","
452 ciphers_valid(const char *names)
458 if (names == NULL || strcmp(names, "") == 0)
460 ciphers = cp = xstrdup(names);
461 for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
462 (p = strsep(&cp, CIPHER_SEP))) {
463 c = cipher_by_name(p);
464 if (c == NULL || c->number != SSH_CIPHER_SSH2) {
465 debug("bad cipher %s [%s]", p, names);
469 debug3("cipher ok: %s [%s]", p, names);
472 debug3("ciphers ok: [%s]", names);
478 * Parses the name of the cipher. Returns the number of the corresponding
479 * cipher, or -1 on error.
483 cipher_number(const char *name)
488 c = cipher_by_name(name);
489 return (c==NULL) ? -1 : c->number;
495 Cipher *c = cipher_by_number(id);
496 return (c==NULL) ? "<unknown>" : c->name;
500 cipher_init(CipherContext *cc, Cipher *cipher,
501 const u_char *key, u_int keylen, const u_char *iv, u_int ivlen)
503 if (keylen < cipher->key_len)
504 fatal("cipher_init: key length %d is insufficient for %s.",
505 keylen, cipher->name);
506 if (iv != NULL && ivlen < cipher->block_size)
507 fatal("cipher_init: iv length %d is insufficient for %s.",
508 ivlen, cipher->name);
510 cipher->setkey(cc, key, keylen);
511 cipher->setiv(cc, iv, ivlen);
515 cipher_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
517 if (len % cc->cipher->block_size)
518 fatal("cipher_encrypt: bad plaintext length %d", len);
519 cc->cipher->encrypt(cc, dest, src, len);
523 cipher_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
525 if (len % cc->cipher->block_size)
526 fatal("cipher_decrypt: bad ciphertext length %d", len);
527 cc->cipher->decrypt(cc, dest, src, len);
531 * Selects the cipher, and keys if by computing the MD5 checksum of the
532 * passphrase and using the resulting 16 bytes as the key.
536 cipher_set_key_string(CipherContext *cc, Cipher *cipher,
537 const char *passphrase)
543 MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase));
544 MD5_Final(digest, &md);
546 cipher_init(cc, cipher, digest, 16, NULL, 0);
548 memset(digest, 0, sizeof(digest));
549 memset(&md, 0, sizeof(md));