version 1.26.2.5, 2001/03/21 18:52:40 |
version 1.27, 2000/05/22 18:42:00 |
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/* |
/* |
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* |
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* cipher.c |
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* |
* Author: Tatu Ylonen <ylo@cs.hut.fi> |
* Author: Tatu Ylonen <ylo@cs.hut.fi> |
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* |
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
* All rights reserved |
* All rights reserved |
* |
* |
* As far as I am concerned, the code I have written for this software |
* Created: Wed Apr 19 17:41:39 1995 ylo |
* can be used freely for any purpose. Any derived versions of this |
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* software must be clearly marked as such, and if the derived work is |
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* incompatible with the protocol description in the RFC file, it must be |
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* called by a name other than "ssh" or "Secure Shell". |
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* |
* |
* |
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* Copyright (c) 1999 Niels Provos. All rights reserved. |
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* Copyright (c) 1999,2000 Markus Friedl. All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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*/ |
*/ |
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#include "includes.h" |
#include "includes.h" |
RCSID("$OpenBSD$"); |
RCSID("$Id$"); |
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#include "xmalloc.h" |
#include "ssh.h" |
#include "log.h" |
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#include "cipher.h" |
#include "cipher.h" |
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#include "xmalloc.h" |
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#include <openssl/md5.h> |
#include <openssl/md5.h> |
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/* no encryption */ |
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void |
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none_setkey(CipherContext *cc, const u_char *key, u_int keylen) |
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{ |
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} |
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void |
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none_setiv(CipherContext *cc, const u_char *iv, u_int ivlen) |
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{ |
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} |
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void |
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none_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) |
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{ |
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memcpy(dest, src, len); |
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} |
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/* DES */ |
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void |
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des_ssh1_setkey(CipherContext *cc, const u_char *key, u_int keylen) |
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{ |
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static int dowarn = 1; |
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if (dowarn) { |
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error("Warning: use of DES is strongly discouraged " |
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"due to cryptographic weaknesses"); |
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dowarn = 0; |
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} |
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des_set_key((void *)key, cc->u.des.key); |
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} |
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void |
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des_ssh1_setiv(CipherContext *cc, const u_char *iv, u_int ivlen) |
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{ |
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memset(cc->u.des.iv, 0, sizeof(cc->u.des.iv)); |
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} |
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void |
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des_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) |
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{ |
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des_ncbc_encrypt(src, dest, len, cc->u.des.key, &cc->u.des.iv, |
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DES_ENCRYPT); |
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} |
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void |
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des_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) |
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{ |
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des_ncbc_encrypt(src, dest, len, cc->u.des.key, &cc->u.des.iv, |
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DES_DECRYPT); |
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} |
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/* 3DES */ |
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void |
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des3_setkey(CipherContext *cc, const u_char *key, u_int keylen) |
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{ |
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des_set_key((void *) key, cc->u.des3.key1); |
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des_set_key((void *) (key+8), cc->u.des3.key2); |
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des_set_key((void *) (key+16), cc->u.des3.key3); |
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} |
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void |
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des3_setiv(CipherContext *cc, const u_char *iv, u_int ivlen) |
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{ |
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memset(cc->u.des3.iv2, 0, sizeof(cc->u.des3.iv2)); |
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memset(cc->u.des3.iv3, 0, sizeof(cc->u.des3.iv3)); |
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if (iv == NULL) |
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return; |
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memcpy(cc->u.des3.iv3, (char *)iv, 8); |
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} |
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void |
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des3_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) |
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{ |
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des_ede3_cbc_encrypt(src, dest, len, |
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cc->u.des3.key1, cc->u.des3.key2, cc->u.des3.key3, |
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&cc->u.des3.iv3, DES_ENCRYPT); |
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} |
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void |
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des3_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) |
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{ |
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des_ede3_cbc_encrypt(src, dest, len, |
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cc->u.des3.key1, cc->u.des3.key2, cc->u.des3.key3, |
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&cc->u.des3.iv3, DES_DECRYPT); |
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} |
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/* |
/* |
* This is used by SSH1: |
* This is used by SSH1: |
* |
* |
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* choosing the X block. |
* choosing the X block. |
*/ |
*/ |
void |
void |
des3_ssh1_setkey(CipherContext *cc, const u_char *key, u_int keylen) |
SSH_3CBC_ENCRYPT(des_key_schedule ks1, |
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des_key_schedule ks2, des_cblock * iv2, |
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des_key_schedule ks3, des_cblock * iv3, |
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unsigned char *dest, unsigned char *src, |
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unsigned int len) |
{ |
{ |
des_set_key((void *) key, cc->u.des3.key1); |
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des_set_key((void *) (key+8), cc->u.des3.key2); |
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if (keylen <= 16) |
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des_set_key((void *) key, cc->u.des3.key3); |
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else |
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des_set_key((void *) (key+16), cc->u.des3.key3); |
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} |
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void |
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des3_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src, |
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u_int len) |
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{ |
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des_cblock iv1; |
des_cblock iv1; |
des_cblock *iv2 = &cc->u.des3.iv2; |
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des_cblock *iv3 = &cc->u.des3.iv3; |
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memcpy(&iv1, iv2, 8); |
memcpy(&iv1, iv2, 8); |
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des_ncbc_encrypt(src, dest, len, cc->u.des3.key1, &iv1, DES_ENCRYPT); |
des_cbc_encrypt(src, dest, len, ks1, &iv1, DES_ENCRYPT); |
des_ncbc_encrypt(dest, dest, len, cc->u.des3.key2, iv2, DES_DECRYPT); |
memcpy(&iv1, dest + len - 8, 8); |
des_ncbc_encrypt(dest, dest, len, cc->u.des3.key3, iv3, DES_ENCRYPT); |
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des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_DECRYPT); |
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memcpy(iv2, &iv1, 8); /* Note how iv1 == iv2 on entry and exit. */ |
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des_cbc_encrypt(dest, dest, len, ks3, iv3, DES_ENCRYPT); |
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memcpy(iv3, dest + len - 8, 8); |
} |
} |
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void |
void |
des3_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src, |
SSH_3CBC_DECRYPT(des_key_schedule ks1, |
u_int len) |
des_key_schedule ks2, des_cblock * iv2, |
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des_key_schedule ks3, des_cblock * iv3, |
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unsigned char *dest, unsigned char *src, |
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unsigned int len) |
{ |
{ |
des_cblock iv1; |
des_cblock iv1; |
des_cblock *iv2 = &cc->u.des3.iv2; |
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des_cblock *iv3 = &cc->u.des3.iv3; |
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memcpy(&iv1, iv2, 8); |
memcpy(&iv1, iv2, 8); |
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des_ncbc_encrypt(src, dest, len, cc->u.des3.key3, iv3, DES_DECRYPT); |
des_cbc_encrypt(src, dest, len, ks3, iv3, DES_DECRYPT); |
des_ncbc_encrypt(dest, dest, len, cc->u.des3.key2, iv2, DES_ENCRYPT); |
memcpy(iv3, src + len - 8, 8); |
des_ncbc_encrypt(dest, dest, len, cc->u.des3.key1, &iv1, DES_DECRYPT); |
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} |
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/* Blowfish */ |
des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_ENCRYPT); |
void |
memcpy(iv2, dest + len - 8, 8); |
blowfish_setkey(CipherContext *cc, const u_char *key, u_int keylen) |
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{ |
des_cbc_encrypt(dest, dest, len, ks1, &iv1, DES_DECRYPT); |
BF_set_key(&cc->u.bf.key, keylen, (u_char *)key); |
/* memcpy(&iv1, iv2, 8); */ |
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/* Note how iv1 == iv2 on entry and exit. */ |
} |
} |
void |
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blowfish_setiv(CipherContext *cc, const u_char *iv, u_int ivlen) |
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{ |
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if (iv == NULL) |
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memset(cc->u.bf.iv, 0, 8); |
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else |
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memcpy(cc->u.bf.iv, (char *)iv, 8); |
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} |
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void |
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blowfish_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, |
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u_int len) |
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{ |
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BF_cbc_encrypt((void *)src, dest, len, &cc->u.bf.key, cc->u.bf.iv, |
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BF_ENCRYPT); |
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} |
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void |
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blowfish_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, |
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u_int len) |
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{ |
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BF_cbc_encrypt((void *)src, dest, len, &cc->u.bf.key, cc->u.bf.iv, |
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BF_DECRYPT); |
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} |
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/* |
/* |
* SSH1 uses a variation on Blowfish, all bytes must be swapped before |
* SSH1 uses a variation on Blowfish, all bytes must be swapped before |
* and after encryption/decryption. Thus the swap_bytes stuff (yuk). |
* and after encryption/decryption. Thus the swap_bytes stuff (yuk). |
*/ |
*/ |
static void |
static void |
swap_bytes(const u_char *src, u_char *dst, int n) |
swap_bytes(const unsigned char *src, unsigned char *dst_, int n) |
{ |
{ |
char c[4]; |
/* dst must be properly aligned. */ |
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u_int32_t *dst = (u_int32_t *) dst_; |
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union { |
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u_int32_t i; |
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char c[4]; |
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} t; |
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/* Process 4 bytes every lap. */ |
/* Process 8 bytes every lap. */ |
for (n = n / 4; n > 0; n--) { |
for (n = n / 8; n > 0; n--) { |
c[3] = *src++; |
t.c[3] = *src++; |
c[2] = *src++; |
t.c[2] = *src++; |
c[1] = *src++; |
t.c[1] = *src++; |
c[0] = *src++; |
t.c[0] = *src++; |
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*dst++ = t.i; |
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*dst++ = c[0]; |
t.c[3] = *src++; |
*dst++ = c[1]; |
t.c[2] = *src++; |
*dst++ = c[2]; |
t.c[1] = *src++; |
*dst++ = c[3]; |
t.c[0] = *src++; |
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*dst++ = t.i; |
} |
} |
} |
} |
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void |
/* |
blowfish_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src, |
* Names of all encryption algorithms. |
u_int len) |
* These must match the numbers defined in cipher.h. |
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*/ |
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static char *cipher_names[] = |
{ |
{ |
swap_bytes(src, dest, len); |
"none", |
BF_cbc_encrypt((void *)dest, dest, len, &cc->u.bf.key, cc->u.bf.iv, |
"idea", |
BF_ENCRYPT); |
"des", |
swap_bytes(dest, dest, len); |
"3des", |
} |
"tss", |
void |
"rc4", |
blowfish_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src, |
"blowfish", |
u_int len) |
"reserved", |
{ |
"blowfish-cbc", |
swap_bytes(src, dest, len); |
"3des-cbc", |
BF_cbc_encrypt((void *)dest, dest, len, &cc->u.bf.key, cc->u.bf.iv, |
"arcfour", |
BF_DECRYPT); |
"cast128-cbc" |
swap_bytes(dest, dest, len); |
}; |
} |
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/* alleged rc4 */ |
/* |
void |
* Returns a bit mask indicating which ciphers are supported by this |
arcfour_setkey(CipherContext *cc, const u_char *key, u_int keylen) |
* implementation. The bit mask has the corresponding bit set of each |
{ |
* supported cipher. |
RC4_set_key(&cc->u.rc4, keylen, (u_char *)key); |
*/ |
} |
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void |
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arcfour_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) |
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{ |
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RC4(&cc->u.rc4, len, (u_char *)src, dest); |
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} |
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/* CAST */ |
unsigned int |
void |
cipher_mask1() |
cast_setkey(CipherContext *cc, const u_char *key, u_int keylen) |
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{ |
{ |
CAST_set_key(&cc->u.cast.key, keylen, (u_char *) key); |
unsigned int mask = 0; |
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mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */ |
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mask |= 1 << SSH_CIPHER_BLOWFISH; |
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return mask; |
} |
} |
void |
unsigned int |
cast_setiv(CipherContext *cc, const u_char *iv, u_int ivlen) |
cipher_mask2() |
{ |
{ |
if (iv == NULL) |
unsigned int mask = 0; |
fatal("no IV for %s.", cc->cipher->name); |
mask |= 1 << SSH_CIPHER_BLOWFISH_CBC; |
memcpy(cc->u.cast.iv, (char *)iv, 8); |
mask |= 1 << SSH_CIPHER_3DES_CBC; |
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mask |= 1 << SSH_CIPHER_ARCFOUR; |
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mask |= 1 << SSH_CIPHER_CAST128_CBC; |
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return mask; |
} |
} |
void |
unsigned int |
cast_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) |
cipher_mask() |
{ |
{ |
CAST_cbc_encrypt(src, dest, len, &cc->u.cast.key, cc->u.cast.iv, |
return cipher_mask1() | cipher_mask2(); |
CAST_ENCRYPT); |
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} |
} |
void |
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cast_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) |
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{ |
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CAST_cbc_encrypt(src, dest, len, &cc->u.cast.key, cc->u.cast.iv, |
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CAST_DECRYPT); |
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} |
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/* RIJNDAEL */ |
/* Returns the name of the cipher. */ |
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#define RIJNDAEL_BLOCKSIZE 16 |
const char * |
void |
cipher_name(int cipher) |
rijndael_setkey(CipherContext *cc, const u_char *key, u_int keylen) |
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{ |
{ |
rijndael_set_key(&cc->u.rijndael.enc, (u4byte *)key, 8*keylen, 1); |
if (cipher < 0 || cipher >= sizeof(cipher_names) / sizeof(cipher_names[0]) || |
rijndael_set_key(&cc->u.rijndael.dec, (u4byte *)key, 8*keylen, 0); |
cipher_names[cipher] == NULL) |
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fatal("cipher_name: bad cipher name: %d", cipher); |
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return cipher_names[cipher]; |
} |
} |
void |
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rijndael_setiv(CipherContext *cc, const u_char *iv, u_int ivlen) |
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{ |
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if (iv == NULL) |
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fatal("no IV for %s.", cc->cipher->name); |
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memcpy((u_char *)cc->u.rijndael.iv, iv, RIJNDAEL_BLOCKSIZE); |
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} |
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void |
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rijndael_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, |
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u_int len) |
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{ |
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rijndael_ctx *ctx = &cc->u.rijndael.enc; |
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u4byte *iv = cc->u.rijndael.iv; |
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u4byte in[4]; |
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u4byte *cprev, *cnow, *plain; |
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int i, blocks = len / RIJNDAEL_BLOCKSIZE; |
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if (len == 0) |
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return; |
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if (len % RIJNDAEL_BLOCKSIZE) |
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fatal("rijndael_cbc_encrypt: bad len %d", len); |
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cnow = (u4byte*) dest; |
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plain = (u4byte*) src; |
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cprev = iv; |
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for(i = 0; i < blocks; i++, plain+=4, cnow+=4) { |
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in[0] = plain[0] ^ cprev[0]; |
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in[1] = plain[1] ^ cprev[1]; |
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in[2] = plain[2] ^ cprev[2]; |
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in[3] = plain[3] ^ cprev[3]; |
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rijndael_encrypt(ctx, in, cnow); |
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cprev = cnow; |
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} |
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memcpy(iv, cprev, RIJNDAEL_BLOCKSIZE); |
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} |
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void |
/* Returns 1 if the name of the ciphers are valid. */ |
rijndael_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, |
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u_int len) |
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{ |
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rijndael_ctx *ctx = &cc->u.rijndael.dec; |
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u4byte *iv = cc->u.rijndael.iv; |
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u4byte ivsaved[4]; |
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u4byte *cnow = (u4byte*) (src+len-RIJNDAEL_BLOCKSIZE); |
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u4byte *plain = (u4byte*) (dest+len-RIJNDAEL_BLOCKSIZE); |
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u4byte *ivp; |
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int i, blocks = len / RIJNDAEL_BLOCKSIZE; |
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if (len == 0) |
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return; |
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if (len % RIJNDAEL_BLOCKSIZE) |
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fatal("rijndael_cbc_decrypt: bad len %d", len); |
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memcpy(ivsaved, cnow, RIJNDAEL_BLOCKSIZE); |
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for(i = blocks; i > 0; i--, cnow-=4, plain-=4) { |
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rijndael_decrypt(ctx, cnow, plain); |
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ivp = (i == 1) ? iv : cnow-4; |
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plain[0] ^= ivp[0]; |
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plain[1] ^= ivp[1]; |
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plain[2] ^= ivp[2]; |
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plain[3] ^= ivp[3]; |
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} |
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memcpy(iv, ivsaved, RIJNDAEL_BLOCKSIZE); |
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} |
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Cipher ciphers[] = { |
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{ "none", |
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SSH_CIPHER_NONE, 8, 0, |
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none_setkey, none_setiv, |
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none_crypt, none_crypt }, |
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{ "des", |
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SSH_CIPHER_DES, 8, 8, |
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des_ssh1_setkey, des_ssh1_setiv, |
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des_ssh1_encrypt, des_ssh1_decrypt }, |
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{ "3des", |
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SSH_CIPHER_3DES, 8, 16, |
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des3_ssh1_setkey, des3_setiv, |
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des3_ssh1_encrypt, des3_ssh1_decrypt }, |
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{ "blowfish", |
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SSH_CIPHER_BLOWFISH, 8, 16, |
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blowfish_setkey, blowfish_setiv, |
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blowfish_ssh1_encrypt, blowfish_ssh1_decrypt }, |
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{ "3des-cbc", |
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SSH_CIPHER_SSH2, 8, 24, |
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des3_setkey, des3_setiv, |
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des3_cbc_encrypt, des3_cbc_decrypt }, |
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{ "blowfish-cbc", |
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SSH_CIPHER_SSH2, 8, 16, |
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blowfish_setkey, blowfish_setiv, |
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blowfish_cbc_encrypt, blowfish_cbc_decrypt }, |
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{ "cast128-cbc", |
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SSH_CIPHER_SSH2, 8, 16, |
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cast_setkey, cast_setiv, |
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cast_cbc_encrypt, cast_cbc_decrypt }, |
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{ "arcfour", |
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SSH_CIPHER_SSH2, 8, 16, |
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arcfour_setkey, none_setiv, |
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arcfour_crypt, arcfour_crypt }, |
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{ "aes128-cbc", |
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SSH_CIPHER_SSH2, 16, 16, |
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rijndael_setkey, rijndael_setiv, |
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rijndael_cbc_encrypt, rijndael_cbc_decrypt }, |
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{ "aes192-cbc", |
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SSH_CIPHER_SSH2, 16, 24, |
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rijndael_setkey, rijndael_setiv, |
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rijndael_cbc_encrypt, rijndael_cbc_decrypt }, |
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{ "aes256-cbc", |
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SSH_CIPHER_SSH2, 16, 32, |
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rijndael_setkey, rijndael_setiv, |
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rijndael_cbc_encrypt, rijndael_cbc_decrypt }, |
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{ "rijndael128-cbc", |
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SSH_CIPHER_SSH2, 16, 16, |
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rijndael_setkey, rijndael_setiv, |
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rijndael_cbc_encrypt, rijndael_cbc_decrypt }, |
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{ "rijndael192-cbc", |
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SSH_CIPHER_SSH2, 16, 24, |
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rijndael_setkey, rijndael_setiv, |
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rijndael_cbc_encrypt, rijndael_cbc_decrypt }, |
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{ "rijndael256-cbc", |
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SSH_CIPHER_SSH2, 16, 32, |
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rijndael_setkey, rijndael_setiv, |
|
rijndael_cbc_encrypt, rijndael_cbc_decrypt }, |
|
{ "rijndael-cbc@lysator.liu.se", |
|
SSH_CIPHER_SSH2, 16, 32, |
|
rijndael_setkey, rijndael_setiv, |
|
rijndael_cbc_encrypt, rijndael_cbc_decrypt }, |
|
{ NULL, SSH_CIPHER_ILLEGAL, 0, 0, NULL, NULL, NULL, NULL } |
|
}; |
|
|
|
/*--*/ |
|
|
|
u_int |
|
cipher_mask_ssh1(int client) |
|
{ |
|
u_int mask = 0; |
|
mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */ |
|
mask |= 1 << SSH_CIPHER_BLOWFISH; |
|
if (client) { |
|
mask |= 1 << SSH_CIPHER_DES; |
|
} |
|
return mask; |
|
} |
|
|
|
Cipher * |
|
cipher_by_name(const char *name) |
|
{ |
|
Cipher *c; |
|
for (c = ciphers; c->name != NULL; c++) |
|
if (strcasecmp(c->name, name) == 0) |
|
return c; |
|
return NULL; |
|
} |
|
|
|
Cipher * |
|
cipher_by_number(int id) |
|
{ |
|
Cipher *c; |
|
for (c = ciphers; c->name != NULL; c++) |
|
if (c->number == id) |
|
return c; |
|
return NULL; |
|
} |
|
|
|
#define CIPHER_SEP "," |
#define CIPHER_SEP "," |
int |
int |
ciphers_valid(const char *names) |
ciphers_valid(const char *names) |
{ |
{ |
Cipher *c; |
char *ciphers; |
char *ciphers, *cp; |
|
char *p; |
char *p; |
|
int i; |
|
|
if (names == NULL || strcmp(names, "") == 0) |
if (names == NULL || strcmp(names, "") == 0) |
return 0; |
return 0; |
ciphers = cp = xstrdup(names); |
ciphers = xstrdup(names); |
for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0'; |
for ((p = strtok(ciphers, CIPHER_SEP)); p; (p = strtok(NULL, CIPHER_SEP))) { |
(p = strsep(&cp, CIPHER_SEP))) { |
i = cipher_number(p); |
c = cipher_by_name(p); |
if (i == -1 || !(cipher_mask2() & (1 << i))) { |
if (c == NULL || c->number != SSH_CIPHER_SSH2) { |
|
debug("bad cipher %s [%s]", p, names); |
|
xfree(ciphers); |
xfree(ciphers); |
return 0; |
return 0; |
} else { |
|
debug3("cipher ok: %s [%s]", p, names); |
|
} |
} |
} |
} |
debug3("ciphers ok: [%s]", names); |
|
xfree(ciphers); |
xfree(ciphers); |
return 1; |
return 1; |
} |
} |
|
|
int |
int |
cipher_number(const char *name) |
cipher_number(const char *name) |
{ |
{ |
Cipher *c; |
int i; |
if (name == NULL) |
if (name == NULL) |
return -1; |
return -1; |
c = cipher_by_name(name); |
for (i = 0; i < sizeof(cipher_names) / sizeof(cipher_names[0]); i++) |
return (c==NULL) ? -1 : c->number; |
if (strcmp(cipher_names[i], name) == 0 && |
|
(cipher_mask() & (1 << i))) |
|
return i; |
|
return -1; |
} |
} |
|
|
char * |
/* |
cipher_name(int id) |
* Selects the cipher, and keys if by computing the MD5 checksum of the |
|
* passphrase and using the resulting 16 bytes as the key. |
|
*/ |
|
|
|
void |
|
cipher_set_key_string(CipherContext *context, int cipher, const char *passphrase) |
{ |
{ |
Cipher *c = cipher_by_number(id); |
MD5_CTX md; |
return (c==NULL) ? "<unknown>" : c->name; |
unsigned char digest[16]; |
|
|
|
MD5_Init(&md); |
|
MD5_Update(&md, (const unsigned char *) passphrase, strlen(passphrase)); |
|
MD5_Final(digest, &md); |
|
|
|
cipher_set_key(context, cipher, digest, 16); |
|
|
|
memset(digest, 0, sizeof(digest)); |
|
memset(&md, 0, sizeof(md)); |
} |
} |
|
|
|
/* Selects the cipher to use and sets the key. */ |
|
|
void |
void |
cipher_init(CipherContext *cc, Cipher *cipher, |
cipher_set_key(CipherContext *context, int cipher, const unsigned char *key, |
const u_char *key, u_int keylen, const u_char *iv, u_int ivlen) |
int keylen) |
{ |
{ |
if (keylen < cipher->key_len) |
unsigned char padded[32]; |
fatal("cipher_init: key length %d is insufficient for %s.", |
|
keylen, cipher->name); |
/* Set cipher type. */ |
if (iv != NULL && ivlen < cipher->block_size) |
context->type = cipher; |
fatal("cipher_init: iv length %d is insufficient for %s.", |
|
ivlen, cipher->name); |
/* Get 32 bytes of key data. Pad if necessary. (So that code |
cc->cipher = cipher; |
below does not need to worry about key size). */ |
cipher->setkey(cc, key, keylen); |
memset(padded, 0, sizeof(padded)); |
cipher->setiv(cc, iv, ivlen); |
memcpy(padded, key, keylen < sizeof(padded) ? keylen : sizeof(padded)); |
|
|
|
/* Initialize the initialization vector. */ |
|
switch (cipher) { |
|
case SSH_CIPHER_NONE: |
|
/* |
|
* Has to stay for authfile saving of private key with no |
|
* passphrase |
|
*/ |
|
break; |
|
|
|
case SSH_CIPHER_3DES: |
|
/* |
|
* Note: the least significant bit of each byte of key is |
|
* parity, and must be ignored by the implementation. 16 |
|
* bytes of key are used (first and last keys are the same). |
|
*/ |
|
if (keylen < 16) |
|
error("Key length %d is insufficient for 3DES.", keylen); |
|
des_set_key((void *) padded, context->u.des3.key1); |
|
des_set_key((void *) (padded + 8), context->u.des3.key2); |
|
if (keylen <= 16) |
|
des_set_key((void *) padded, context->u.des3.key3); |
|
else |
|
des_set_key((void *) (padded + 16), context->u.des3.key3); |
|
memset(context->u.des3.iv2, 0, sizeof(context->u.des3.iv2)); |
|
memset(context->u.des3.iv3, 0, sizeof(context->u.des3.iv3)); |
|
break; |
|
|
|
case SSH_CIPHER_BLOWFISH: |
|
if (keylen < 16) |
|
error("Key length %d is insufficient for blowfish.", keylen); |
|
BF_set_key(&context->u.bf.key, keylen, padded); |
|
memset(context->u.bf.iv, 0, 8); |
|
break; |
|
|
|
case SSH_CIPHER_3DES_CBC: |
|
case SSH_CIPHER_BLOWFISH_CBC: |
|
case SSH_CIPHER_ARCFOUR: |
|
case SSH_CIPHER_CAST128_CBC: |
|
fatal("cipher_set_key: illegal cipher: %s", cipher_name(cipher)); |
|
break; |
|
|
|
default: |
|
fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher)); |
|
} |
|
memset(padded, 0, sizeof(padded)); |
} |
} |
|
|
void |
void |
cipher_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) |
cipher_set_key_iv(CipherContext * context, int cipher, |
|
const unsigned char *key, int keylen, |
|
const unsigned char *iv, int ivlen) |
{ |
{ |
if (len % cc->cipher->block_size) |
/* Set cipher type. */ |
fatal("cipher_encrypt: bad plaintext length %d", len); |
context->type = cipher; |
cc->cipher->encrypt(cc, dest, src, len); |
|
|
/* Initialize the initialization vector. */ |
|
switch (cipher) { |
|
case SSH_CIPHER_NONE: |
|
break; |
|
|
|
case SSH_CIPHER_3DES: |
|
case SSH_CIPHER_BLOWFISH: |
|
fatal("cipher_set_key_iv: illegal cipher: %s", cipher_name(cipher)); |
|
break; |
|
|
|
case SSH_CIPHER_3DES_CBC: |
|
if (keylen < 24) |
|
error("Key length %d is insufficient for 3des-cbc.", keylen); |
|
des_set_key((void *) key, context->u.des3.key1); |
|
des_set_key((void *) (key+8), context->u.des3.key2); |
|
des_set_key((void *) (key+16), context->u.des3.key3); |
|
if (ivlen < 8) |
|
error("IV length %d is insufficient for 3des-cbc.", ivlen); |
|
memcpy(context->u.des3.iv3, (char *)iv, 8); |
|
break; |
|
|
|
case SSH_CIPHER_BLOWFISH_CBC: |
|
if (keylen < 16) |
|
error("Key length %d is insufficient for blowfish.", keylen); |
|
if (ivlen < 8) |
|
error("IV length %d is insufficient for blowfish.", ivlen); |
|
BF_set_key(&context->u.bf.key, keylen, (unsigned char *)key); |
|
memcpy(context->u.bf.iv, (char *)iv, 8); |
|
break; |
|
|
|
case SSH_CIPHER_ARCFOUR: |
|
if (keylen < 16) |
|
error("Key length %d is insufficient for arcfour.", keylen); |
|
RC4_set_key(&context->u.rc4, keylen, (unsigned char *)key); |
|
break; |
|
|
|
case SSH_CIPHER_CAST128_CBC: |
|
if (keylen < 16) |
|
error("Key length %d is insufficient for cast128.", keylen); |
|
if (ivlen < 8) |
|
error("IV length %d is insufficient for cast128.", ivlen); |
|
CAST_set_key(&context->u.cast.key, keylen, (unsigned char *) key); |
|
memcpy(context->u.cast.iv, (char *)iv, 8); |
|
break; |
|
|
|
default: |
|
fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher)); |
|
} |
} |
} |
|
|
|
/* Encrypts data using the cipher. */ |
|
|
void |
void |
cipher_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) |
cipher_encrypt(CipherContext *context, unsigned char *dest, |
|
const unsigned char *src, unsigned int len) |
{ |
{ |
if (len % cc->cipher->block_size) |
if ((len & 7) != 0) |
fatal("cipher_decrypt: bad ciphertext length %d", len); |
fatal("cipher_encrypt: bad plaintext length %d", len); |
cc->cipher->decrypt(cc, dest, src, len); |
|
|
switch (context->type) { |
|
case SSH_CIPHER_NONE: |
|
memcpy(dest, src, len); |
|
break; |
|
|
|
case SSH_CIPHER_3DES: |
|
SSH_3CBC_ENCRYPT(context->u.des3.key1, |
|
context->u.des3.key2, &context->u.des3.iv2, |
|
context->u.des3.key3, &context->u.des3.iv3, |
|
dest, (unsigned char *) src, len); |
|
break; |
|
|
|
case SSH_CIPHER_BLOWFISH: |
|
swap_bytes(src, dest, len); |
|
BF_cbc_encrypt(dest, dest, len, |
|
&context->u.bf.key, context->u.bf.iv, |
|
BF_ENCRYPT); |
|
swap_bytes(dest, dest, len); |
|
break; |
|
|
|
case SSH_CIPHER_BLOWFISH_CBC: |
|
BF_cbc_encrypt((void *)src, dest, len, |
|
&context->u.bf.key, context->u.bf.iv, |
|
BF_ENCRYPT); |
|
break; |
|
|
|
case SSH_CIPHER_3DES_CBC: |
|
des_ede3_cbc_encrypt(src, dest, len, |
|
context->u.des3.key1, context->u.des3.key2, |
|
context->u.des3.key3, &context->u.des3.iv3, DES_ENCRYPT); |
|
break; |
|
|
|
case SSH_CIPHER_ARCFOUR: |
|
RC4(&context->u.rc4, len, (unsigned char *)src, dest); |
|
break; |
|
|
|
case SSH_CIPHER_CAST128_CBC: |
|
CAST_cbc_encrypt(src, dest, len, |
|
&context->u.cast.key, context->u.cast.iv, CAST_ENCRYPT); |
|
break; |
|
|
|
default: |
|
fatal("cipher_encrypt: unknown cipher: %s", cipher_name(context->type)); |
|
} |
} |
} |
|
|
/* |
/* Decrypts data using the cipher. */ |
* Selects the cipher, and keys if by computing the MD5 checksum of the |
|
* passphrase and using the resulting 16 bytes as the key. |
|
*/ |
|
|
|
void |
void |
cipher_set_key_string(CipherContext *cc, Cipher *cipher, |
cipher_decrypt(CipherContext *context, unsigned char *dest, |
const char *passphrase) |
const unsigned char *src, unsigned int len) |
{ |
{ |
MD5_CTX md; |
if ((len & 7) != 0) |
u_char digest[16]; |
fatal("cipher_decrypt: bad ciphertext length %d", len); |
|
|
MD5_Init(&md); |
switch (context->type) { |
MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase)); |
case SSH_CIPHER_NONE: |
MD5_Final(digest, &md); |
memcpy(dest, src, len); |
|
break; |
|
|
cipher_init(cc, cipher, digest, 16, NULL, 0); |
case SSH_CIPHER_3DES: |
|
SSH_3CBC_DECRYPT(context->u.des3.key1, |
|
context->u.des3.key2, &context->u.des3.iv2, |
|
context->u.des3.key3, &context->u.des3.iv3, |
|
dest, (unsigned char *) src, len); |
|
break; |
|
|
memset(digest, 0, sizeof(digest)); |
case SSH_CIPHER_BLOWFISH: |
memset(&md, 0, sizeof(md)); |
swap_bytes(src, dest, len); |
|
BF_cbc_encrypt((void *) dest, dest, len, |
|
&context->u.bf.key, context->u.bf.iv, |
|
BF_DECRYPT); |
|
swap_bytes(dest, dest, len); |
|
break; |
|
|
|
case SSH_CIPHER_BLOWFISH_CBC: |
|
BF_cbc_encrypt((void *) src, dest, len, |
|
&context->u.bf.key, context->u.bf.iv, |
|
BF_DECRYPT); |
|
break; |
|
|
|
case SSH_CIPHER_3DES_CBC: |
|
des_ede3_cbc_encrypt(src, dest, len, |
|
context->u.des3.key1, context->u.des3.key2, |
|
context->u.des3.key3, &context->u.des3.iv3, DES_DECRYPT); |
|
break; |
|
|
|
case SSH_CIPHER_ARCFOUR: |
|
RC4(&context->u.rc4, len, (unsigned char *)src, dest); |
|
break; |
|
|
|
case SSH_CIPHER_CAST128_CBC: |
|
CAST_cbc_encrypt(src, dest, len, |
|
&context->u.cast.key, context->u.cast.iv, CAST_DECRYPT); |
|
break; |
|
|
|
default: |
|
fatal("cipher_decrypt: unknown cipher: %s", cipher_name(context->type)); |
|
} |
} |
} |