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/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*
*
* Copyright (c) 1999 Niels Provos. All rights reserved.
* Copyright (c) 1999, 2000 Markus Friedl. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
RCSID("$OpenBSD: cipher.c,v 1.68 2004/01/23 19:26:33 hshoexer Exp $");
#include "xmalloc.h"
#include "log.h"
#include "cipher.h"
#include <openssl/md5.h>
#if OPENSSL_VERSION_NUMBER < 0x00906000L
#define SSH_OLD_EVP
#define EVP_CIPHER_CTX_get_app_data(e) ((e)->app_data)
#endif
#if OPENSSL_VERSION_NUMBER < 0x00907000L
extern const EVP_CIPHER *evp_rijndael(void);
extern void ssh_rijndael_iv(EVP_CIPHER_CTX *, int, u_char *, u_int);
#endif
#if !defined(EVP_CTRL_SET_ACSS_MODE)
# if (OPENSSL_VERSION_NUMBER >= 0x00907000L)
extern const EVP_CIPHER *evp_acss(void);
# define EVP_acss evp_acss
# define EVP_CTRL_SET_ACSS_MODE xxx /* used below */
# else
# define EVP_acss NULL /* Don't try to support ACSS on older OpenSSL */
# endif /* (OPENSSL_VERSION_NUMBER >= 0x00906000L) */
#endif /* !defined(EVP_CTRL_SET_ACSS_MODE) */
extern const EVP_CIPHER *evp_ssh1_bf(void);
extern const EVP_CIPHER *evp_ssh1_3des(void);
extern void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
extern const EVP_CIPHER *evp_aes_128_ctr(void);
extern void ssh_aes_ctr_iv(EVP_CIPHER_CTX *, int, u_char *, u_int);
struct Cipher {
char *name;
int number; /* for ssh1 only */
u_int block_size;
u_int key_len;
const EVP_CIPHER *(*evptype)(void);
} ciphers[] = {
{ "none", SSH_CIPHER_NONE, 8, 0, EVP_enc_null },
{ "des", SSH_CIPHER_DES, 8, 8, EVP_des_cbc },
{ "3des", SSH_CIPHER_3DES, 8, 16, evp_ssh1_3des },
{ "blowfish", SSH_CIPHER_BLOWFISH, 8, 32, evp_ssh1_bf },
{ "3des-cbc", SSH_CIPHER_SSH2, 8, 24, EVP_des_ede3_cbc },
{ "blowfish-cbc", SSH_CIPHER_SSH2, 8, 16, EVP_bf_cbc },
{ "cast128-cbc", SSH_CIPHER_SSH2, 8, 16, EVP_cast5_cbc },
{ "arcfour", SSH_CIPHER_SSH2, 8, 16, EVP_rc4 },
#if OPENSSL_VERSION_NUMBER < 0x00907000L
{ "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, evp_rijndael },
{ "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, evp_rijndael },
{ "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, evp_rijndael },
{ "rijndael-cbc@lysator.liu.se",
SSH_CIPHER_SSH2, 16, 32, evp_rijndael },
#else
{ "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, EVP_aes_128_cbc },
{ "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, EVP_aes_192_cbc },
{ "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, EVP_aes_256_cbc },
{ "rijndael-cbc@lysator.liu.se",
SSH_CIPHER_SSH2, 16, 32, EVP_aes_256_cbc },
#endif
#if OPENSSL_VERSION_NUMBER >= 0x00905000L
{ "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, evp_aes_128_ctr },
{ "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, evp_aes_128_ctr },
{ "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, evp_aes_128_ctr },
#endif
#if defined(EVP_CTRL_SET_ACSS_MODE)
{ "acss@openssh.org", SSH_CIPHER_SSH2, 16, 5, EVP_acss },
#endif
{ NULL, SSH_CIPHER_ILLEGAL, 0, 0, NULL }
};
/*--*/
u_int
cipher_blocksize(const Cipher *c)
{
return (c->block_size);
}
u_int
cipher_keylen(const Cipher *c)
{
return (c->key_len);
}
u_int
cipher_get_number(const Cipher *c)
{
return (c->number);
}
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 ","
int
ciphers_valid(const char *names)
{
Cipher *c;
char *ciphers, *cp;
char *p;
if (names == NULL || strcmp(names, "") == 0)
return 0;
ciphers = cp = xstrdup(names);
for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
(p = strsep(&cp, CIPHER_SEP))) {
c = cipher_by_name(p);
if (c == NULL || c->number != SSH_CIPHER_SSH2) {
debug("bad cipher %s [%s]", p, names);
xfree(ciphers);
return 0;
} else {
debug3("cipher ok: %s [%s]", p, names);
}
}
debug3("ciphers ok: [%s]", names);
xfree(ciphers);
return 1;
}
/*
* Parses the name of the cipher. Returns the number of the corresponding
* cipher, or -1 on error.
*/
int
cipher_number(const char *name)
{
Cipher *c;
if (name == NULL)
return -1;
c = cipher_by_name(name);
return (c==NULL) ? -1 : c->number;
}
char *
cipher_name(int id)
{
Cipher *c = cipher_by_number(id);
return (c==NULL) ? "<unknown>" : c->name;
}
void
cipher_init(CipherContext *cc, Cipher *cipher,
const u_char *key, u_int keylen, const u_char *iv, u_int ivlen,
int encrypt)
{
static int dowarn = 1;
#ifdef SSH_OLD_EVP
EVP_CIPHER *type;
#else
const EVP_CIPHER *type;
#endif
int klen;
if (cipher->number == SSH_CIPHER_DES) {
if (dowarn) {
error("Warning: use of DES is strongly discouraged "
"due to cryptographic weaknesses");
dowarn = 0;
}
if (keylen > 8)
keylen = 8;
}
cc->plaintext = (cipher->number == SSH_CIPHER_NONE);
if (keylen < cipher->key_len)
fatal("cipher_init: key length %d is insufficient for %s.",
keylen, cipher->name);
if (iv != NULL && ivlen < cipher->
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