563 lines
15 KiB
C
563 lines
15 KiB
C
/* $NetBSD: cipher.c,v 1.3 2001/01/14 05:22:32 itojun Exp $ */
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
|
|
/* from OpenBSD: cipher.c,v 1.41 2000/12/19 23:17:56 markus Exp */
|
|
|
|
#include <sys/cdefs.h>
|
|
#ifndef lint
|
|
__RCSID("$NetBSD: cipher.c,v 1.3 2001/01/14 05:22:32 itojun Exp $");
|
|
#endif
|
|
|
|
#include "includes.h"
|
|
|
|
#include "ssh.h"
|
|
#include "xmalloc.h"
|
|
|
|
#include <openssl/md5.h>
|
|
|
|
|
|
/* no encryption */
|
|
static void
|
|
none_setkey(CipherContext *cc, const u_char *key, u_int keylen)
|
|
{
|
|
}
|
|
static void
|
|
none_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
|
|
{
|
|
}
|
|
static void
|
|
none_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
|
|
{
|
|
memcpy(dest, src, len);
|
|
}
|
|
|
|
/* DES */
|
|
static void
|
|
des_ssh1_setkey(CipherContext *cc, const u_char *key, u_int keylen)
|
|
{
|
|
static int dowarn = 1;
|
|
if (dowarn) {
|
|
error("Warning: use of DES is strongly discouraged "
|
|
"due to cryptographic weaknesses");
|
|
dowarn = 0;
|
|
}
|
|
des_set_key((void *)key, cc->u.des.key);
|
|
}
|
|
static void
|
|
des_ssh1_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
|
|
{
|
|
memset(cc->u.des.iv, 0, sizeof(cc->u.des.iv));
|
|
}
|
|
static void
|
|
des_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
|
|
{
|
|
des_ncbc_encrypt(src, dest, len, cc->u.des.key, &cc->u.des.iv,
|
|
DES_ENCRYPT);
|
|
}
|
|
static void
|
|
des_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
|
|
{
|
|
des_ncbc_encrypt(src, dest, len, cc->u.des.key, &cc->u.des.iv,
|
|
DES_DECRYPT);
|
|
}
|
|
|
|
/* 3DES */
|
|
static void
|
|
des3_setkey(CipherContext *cc, const u_char *key, u_int keylen)
|
|
{
|
|
des_set_key((void *) key, cc->u.des3.key1);
|
|
des_set_key((void *) (key+8), cc->u.des3.key2);
|
|
des_set_key((void *) (key+16), cc->u.des3.key3);
|
|
}
|
|
static void
|
|
des3_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
|
|
{
|
|
memset(cc->u.des3.iv2, 0, sizeof(cc->u.des3.iv2));
|
|
memset(cc->u.des3.iv3, 0, sizeof(cc->u.des3.iv3));
|
|
if (iv == NULL)
|
|
return;
|
|
memcpy(cc->u.des3.iv3, (char *)iv, 8);
|
|
}
|
|
static void
|
|
des3_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
|
|
{
|
|
des_ede3_cbc_encrypt(src, dest, len,
|
|
cc->u.des3.key1, cc->u.des3.key2, cc->u.des3.key3,
|
|
&cc->u.des3.iv3, DES_ENCRYPT);
|
|
}
|
|
static void
|
|
des3_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
|
|
{
|
|
des_ede3_cbc_encrypt(src, dest, len,
|
|
cc->u.des3.key1, cc->u.des3.key2, cc->u.des3.key3,
|
|
&cc->u.des3.iv3, DES_DECRYPT);
|
|
}
|
|
|
|
/*
|
|
* This is used by SSH1:
|
|
*
|
|
* What kind of triple DES are these 2 routines?
|
|
*
|
|
* Why is there a redundant initialization vector?
|
|
*
|
|
* If only iv3 was used, then, this would till effect have been
|
|
* outer-cbc. However, there is also a private iv1 == iv2 which
|
|
* perhaps makes differential analysis easier. On the other hand, the
|
|
* private iv1 probably makes the CRC-32 attack ineffective. This is a
|
|
* result of that there is no longer any known iv1 to use when
|
|
* choosing the X block.
|
|
*/
|
|
static void
|
|
des3_ssh1_setkey(CipherContext *cc, const u_char *key, u_int keylen)
|
|
{
|
|
des_set_key((void *) key, cc->u.des3.key1);
|
|
des_set_key((void *) (key+8), cc->u.des3.key2);
|
|
if (keylen <= 16)
|
|
des_set_key((void *) key, cc->u.des3.key3);
|
|
else
|
|
des_set_key((void *) (key+16), cc->u.des3.key3);
|
|
}
|
|
static void
|
|
des3_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
|
|
u_int len)
|
|
{
|
|
des_cblock iv1;
|
|
des_cblock *iv2 = &cc->u.des3.iv2;
|
|
des_cblock *iv3 = &cc->u.des3.iv3;
|
|
|
|
memcpy(&iv1, iv2, 8);
|
|
|
|
des_ncbc_encrypt(src, dest, len, cc->u.des3.key1, &iv1, DES_ENCRYPT);
|
|
des_ncbc_encrypt(dest, dest, len, cc->u.des3.key2, iv2, DES_DECRYPT);
|
|
des_ncbc_encrypt(dest, dest, len, cc->u.des3.key3, iv3, DES_ENCRYPT);
|
|
}
|
|
static void
|
|
des3_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
|
|
u_int len)
|
|
{
|
|
des_cblock iv1;
|
|
des_cblock *iv2 = &cc->u.des3.iv2;
|
|
des_cblock *iv3 = &cc->u.des3.iv3;
|
|
|
|
memcpy(&iv1, iv2, 8);
|
|
|
|
des_ncbc_encrypt(src, dest, len, cc->u.des3.key3, iv3, DES_DECRYPT);
|
|
des_ncbc_encrypt(dest, dest, len, cc->u.des3.key2, iv2, DES_ENCRYPT);
|
|
des_ncbc_encrypt(dest, dest, len, cc->u.des3.key1, &iv1, DES_DECRYPT);
|
|
}
|
|
|
|
/* Blowfish */
|
|
static void
|
|
blowfish_setkey(CipherContext *cc, const u_char *key, u_int keylen)
|
|
{
|
|
BF_set_key(&cc->u.bf.key, keylen, (u_char *)key);
|
|
}
|
|
static void
|
|
blowfish_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
|
|
{
|
|
if (iv == NULL)
|
|
memset(cc->u.bf.iv, 0, 8);
|
|
else
|
|
memcpy(cc->u.bf.iv, (char *)iv, 8);
|
|
}
|
|
static void
|
|
blowfish_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
|
|
u_int len)
|
|
{
|
|
BF_cbc_encrypt((void *)src, dest, len, &cc->u.bf.key, cc->u.bf.iv,
|
|
BF_ENCRYPT);
|
|
}
|
|
static void
|
|
blowfish_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
|
|
u_int len)
|
|
{
|
|
BF_cbc_encrypt((void *)src, dest, len, &cc->u.bf.key, cc->u.bf.iv,
|
|
BF_DECRYPT);
|
|
}
|
|
|
|
/*
|
|
* SSH1 uses a variation on Blowfish, all bytes must be swapped before
|
|
* and after encryption/decryption. Thus the swap_bytes stuff (yuk).
|
|
*/
|
|
static void
|
|
swap_bytes(const u_char *src, u_char *dst, int n)
|
|
{
|
|
char c[4];
|
|
|
|
/* Process 4 bytes every lap. */
|
|
for (n = n / 4; n > 0; n--) {
|
|
c[3] = *src++;
|
|
c[2] = *src++;
|
|
c[1] = *src++;
|
|
c[0] = *src++;
|
|
|
|
*dst++ = c[0];
|
|
*dst++ = c[1];
|
|
*dst++ = c[2];
|
|
*dst++ = c[3];
|
|
}
|
|
}
|
|
|
|
static void
|
|
blowfish_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
|
|
u_int len)
|
|
{
|
|
swap_bytes(src, dest, len);
|
|
BF_cbc_encrypt((void *)dest, dest, len, &cc->u.bf.key, cc->u.bf.iv,
|
|
BF_ENCRYPT);
|
|
swap_bytes(dest, dest, len);
|
|
}
|
|
static void
|
|
blowfish_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
|
|
u_int len)
|
|
{
|
|
swap_bytes(src, dest, len);
|
|
BF_cbc_encrypt((void *)dest, dest, len, &cc->u.bf.key, cc->u.bf.iv,
|
|
BF_DECRYPT);
|
|
swap_bytes(dest, dest, len);
|
|
}
|
|
|
|
/* alleged rc4 */
|
|
static void
|
|
arcfour_setkey(CipherContext *cc, const u_char *key, u_int keylen)
|
|
{
|
|
RC4_set_key(&cc->u.rc4, keylen, (u_char *)key);
|
|
}
|
|
static void
|
|
arcfour_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
|
|
{
|
|
RC4(&cc->u.rc4, len, (u_char *)src, dest);
|
|
}
|
|
|
|
/* CAST */
|
|
static void
|
|
cast_setkey(CipherContext *cc, const u_char *key, u_int keylen)
|
|
{
|
|
CAST_set_key(&cc->u.cast.key, keylen, (u_char *) key);
|
|
}
|
|
static void
|
|
cast_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
|
|
{
|
|
if (iv == NULL)
|
|
fatal("no IV for %s.", cc->cipher->name);
|
|
memcpy(cc->u.cast.iv, (char *)iv, 8);
|
|
}
|
|
static void
|
|
cast_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
|
|
{
|
|
CAST_cbc_encrypt(src, dest, len, &cc->u.cast.key, cc->u.cast.iv,
|
|
CAST_ENCRYPT);
|
|
}
|
|
static void
|
|
cast_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
|
|
{
|
|
CAST_cbc_encrypt(src, dest, len, &cc->u.cast.key, cc->u.cast.iv,
|
|
CAST_DECRYPT);
|
|
}
|
|
|
|
/* RIJNDAEL */
|
|
|
|
#define RIJNDAEL_BLOCKSIZE 16
|
|
static void
|
|
rijndael_setkey(CipherContext *cc, const u_char *key, u_int keylen)
|
|
{
|
|
rijndael_set_key(&cc->u.rijndael.enc, (u4byte *)key, 8*keylen, 1);
|
|
rijndael_set_key(&cc->u.rijndael.dec, (u4byte *)key, 8*keylen, 0);
|
|
}
|
|
static void
|
|
rijndael_setiv(CipherContext *cc, const u_char *iv, u_int ivlen)
|
|
{
|
|
if (iv == NULL)
|
|
fatal("no IV for %s.", cc->cipher->name);
|
|
memcpy((u_char *)cc->u.rijndael.iv, iv, RIJNDAEL_BLOCKSIZE);
|
|
}
|
|
static void
|
|
rijndael_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src,
|
|
u_int len)
|
|
{
|
|
rijndael_ctx *ctx = &cc->u.rijndael.enc;
|
|
u4byte *iv = cc->u.rijndael.iv;
|
|
u4byte in[4];
|
|
u4byte *cprev, *cnow, *plain;
|
|
int i, blocks = len / RIJNDAEL_BLOCKSIZE;
|
|
if (len == 0)
|
|
return;
|
|
if (len % RIJNDAEL_BLOCKSIZE)
|
|
fatal("rijndael_cbc_encrypt: bad len %d", len);
|
|
cnow = (u4byte*) dest;
|
|
plain = (u4byte*) src;
|
|
cprev = iv;
|
|
for(i = 0; i < blocks; i++, plain+=4, cnow+=4) {
|
|
in[0] = plain[0] ^ cprev[0];
|
|
in[1] = plain[1] ^ cprev[1];
|
|
in[2] = plain[2] ^ cprev[2];
|
|
in[3] = plain[3] ^ cprev[3];
|
|
rijndael_encrypt(ctx, in, cnow);
|
|
cprev = cnow;
|
|
}
|
|
memcpy(iv, cprev, RIJNDAEL_BLOCKSIZE);
|
|
}
|
|
|
|
static void
|
|
rijndael_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src,
|
|
u_int len)
|
|
{
|
|
rijndael_ctx *ctx = &cc->u.rijndael.dec;
|
|
u4byte *iv = cc->u.rijndael.iv;
|
|
u4byte ivsaved[4];
|
|
u4byte *cnow = (u4byte*) (src+len-RIJNDAEL_BLOCKSIZE);
|
|
u4byte *plain = (u4byte*) (dest+len-RIJNDAEL_BLOCKSIZE);
|
|
u4byte *ivp;
|
|
int i, blocks = len / RIJNDAEL_BLOCKSIZE;
|
|
if (len == 0)
|
|
return;
|
|
if (len % RIJNDAEL_BLOCKSIZE)
|
|
fatal("rijndael_cbc_decrypt: bad len %d", len);
|
|
memcpy(ivsaved, cnow, RIJNDAEL_BLOCKSIZE);
|
|
for(i = blocks; i > 0; i--, cnow-=4, plain-=4) {
|
|
rijndael_decrypt(ctx, cnow, plain);
|
|
ivp = (i == 1) ? iv : cnow-4;
|
|
plain[0] ^= ivp[0];
|
|
plain[1] ^= ivp[1];
|
|
plain[2] ^= ivp[2];
|
|
plain[3] ^= ivp[3];
|
|
}
|
|
memcpy(iv, ivsaved, RIJNDAEL_BLOCKSIZE);
|
|
}
|
|
|
|
Cipher ciphers[] = {
|
|
{ "none",
|
|
SSH_CIPHER_NONE, 8, 0,
|
|
none_setkey, none_setiv,
|
|
none_crypt, none_crypt },
|
|
{ "des",
|
|
SSH_CIPHER_DES, 8, 8,
|
|
des_ssh1_setkey, des_ssh1_setiv,
|
|
des_ssh1_encrypt, des_ssh1_decrypt },
|
|
{ "3des",
|
|
SSH_CIPHER_3DES, 8, 16,
|
|
des3_ssh1_setkey, des3_setiv,
|
|
des3_ssh1_encrypt, des3_ssh1_decrypt },
|
|
{ "blowfish",
|
|
SSH_CIPHER_BLOWFISH, 8, 16,
|
|
blowfish_setkey, blowfish_setiv,
|
|
blowfish_ssh1_encrypt, blowfish_ssh1_decrypt },
|
|
|
|
{ "3des-cbc",
|
|
SSH_CIPHER_SSH2, 8, 24,
|
|
des3_setkey, des3_setiv,
|
|
des3_cbc_encrypt, des3_cbc_decrypt },
|
|
{ "blowfish-cbc",
|
|
SSH_CIPHER_SSH2, 8, 16,
|
|
blowfish_setkey, blowfish_setiv,
|
|
blowfish_cbc_encrypt, blowfish_cbc_decrypt },
|
|
{ "cast128-cbc",
|
|
SSH_CIPHER_SSH2, 8, 16,
|
|
cast_setkey, cast_setiv,
|
|
cast_cbc_encrypt, cast_cbc_decrypt },
|
|
{ "arcfour",
|
|
SSH_CIPHER_SSH2, 8, 16,
|
|
arcfour_setkey, none_setiv,
|
|
arcfour_crypt, arcfour_crypt },
|
|
{ "aes128-cbc",
|
|
SSH_CIPHER_SSH2, 16, 16,
|
|
rijndael_setkey, rijndael_setiv,
|
|
rijndael_cbc_encrypt, rijndael_cbc_decrypt },
|
|
{ "aes192-cbc",
|
|
SSH_CIPHER_SSH2, 16, 24,
|
|
rijndael_setkey, rijndael_setiv,
|
|
rijndael_cbc_encrypt, rijndael_cbc_decrypt },
|
|
{ "aes256-cbc",
|
|
SSH_CIPHER_SSH2, 16, 32,
|
|
rijndael_setkey, rijndael_setiv,
|
|
rijndael_cbc_encrypt, rijndael_cbc_decrypt },
|
|
{ "rijndael128-cbc",
|
|
SSH_CIPHER_SSH2, 16, 16,
|
|
rijndael_setkey, rijndael_setiv,
|
|
rijndael_cbc_encrypt, rijndael_cbc_decrypt },
|
|
{ "rijndael192-cbc",
|
|
SSH_CIPHER_SSH2, 16, 24,
|
|
rijndael_setkey, rijndael_setiv,
|
|
rijndael_cbc_encrypt, rijndael_cbc_decrypt },
|
|
{ "rijndael256-cbc",
|
|
SSH_CIPHER_SSH2, 16, 32,
|
|
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 ","
|
|
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)
|
|
{
|
|
if (keylen < cipher->key_len)
|
|
fatal("cipher_init: key length %d is insufficient for %s.",
|
|
keylen, cipher->name);
|
|
if (iv != NULL && ivlen < cipher->block_size)
|
|
fatal("cipher_init: iv length %d is insufficient for %s.",
|
|
ivlen, cipher->name);
|
|
cc->cipher = cipher;
|
|
cipher->setkey(cc, key, keylen);
|
|
cipher->setiv(cc, iv, ivlen);
|
|
}
|
|
|
|
void
|
|
cipher_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
|
|
{
|
|
if (len % cc->cipher->block_size)
|
|
fatal("cipher_encrypt: bad plaintext length %d", len);
|
|
cc->cipher->encrypt(cc, dest, src, len);
|
|
}
|
|
|
|
void
|
|
cipher_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
|
|
{
|
|
if (len % cc->cipher->block_size)
|
|
fatal("cipher_decrypt: bad ciphertext length %d", len);
|
|
cc->cipher->decrypt(cc, dest, src, len);
|
|
}
|
|
|
|
/*
|
|
* 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 *cc, Cipher *cipher,
|
|
const char *passphrase)
|
|
{
|
|
MD5_CTX md;
|
|
u_char digest[16];
|
|
|
|
MD5_Init(&md);
|
|
MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase));
|
|
MD5_Final(digest, &md);
|
|
|
|
cipher_init(cc, cipher, digest, 16, NULL, 0);
|
|
|
|
memset(digest, 0, sizeof(digest));
|
|
memset(&md, 0, sizeof(md));
|
|
}
|