/*
* Copyright (c) 1996
* Bill Paul <wpaul@ctr.columbia.edu>. 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Bill Paul.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``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 Bill Paul OR CONTRIBUTORS 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 <sys/types.h>
#include <sys/param.h>
#include <dirent.h>
#include <dlfcn.h>
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <rpc/des_crypt.h>
#include <rpc/des.h>
#include "crypt.h"
#ifndef lint
static const char rcsid[] =
"$FreeBSD$";
#endif /* not lint */
/*
* The U.S. government stupidly believes that a) it can keep strong
* crypto code a secret and b) that doing so somehow protects national
* interests. It's wrong on both counts, but until it listens to reason
* we have to make certain compromises so it doesn't have an excuse to
* throw us in federal prison.
*
* Consequently, the core OS ships without DES support, and keyserv
* defaults to using ARCFOUR with only a 40 bit key, just like nutscrape.
* This breaks compatibility with Secure RPC on other systems, but it
* allows Secure RPC to work between FreeBSD systems that don't have the
* DES package installed without throwing security totally out the window.
*
* In order to avoid having to supply two versions of keyserv (one with
* DES and one without), we use dlopen() and friends to load libdes.so
* into our address space at runtime. We check for the presence of
* /usr/lib/libdes.so.3.0 at startup and load it if we find it. If we
* can't find it, or the __des_crypt symbol doesn't exist, we fall back
* to the ARCFOUR encryption code. The user can specify another path using
* the -p flag.
*/
/* arcfour.h */
typedef struct arcfour_key
{
unsigned char state[256];
unsigned char x;
unsigned char y;
} arcfour_key;
static void prepare_key(unsigned char *key_data_ptr,int key_data_len,
arcfour_key *key);
static void arcfour(unsigned char *buffer_ptr,int buffer_len,arcfour_key * key);
static void swap_byte(unsigned char *a, unsigned char *b);
static void prepare_key(unsigned char *key_data_ptr, int key_data_len,
arcfour_key *key)
{
unsigned char index1;
unsigned char index2;
unsigned char* state;
short counter;
state = &key->state[0];
for(counter = 0; counter < 256; counter++)
state[counter] = counter;
key->x = 0;
key->y = 0;
index1 = 0;
index2 = 0;
for(counter = 0; counter < 256; counter++)
{
index2 = (key_data_ptr[index1] + state[counter] +
index2) % 256;
swap_byte(&state[counter], &state[index2]);
index1 = (index1 + 1) % key_data_len;
}
}
static void arcfour(unsigned char *buffer_ptr, int buffer_len, arcfour_key *key)
{
unsigned char x;
unsigned char y;
unsigned char* state;
unsigned char xorIndex;
short counter;
x = key->x;
y = key->y;
state = &key->state[0];
for(counter = 0; counter < buffer_len; counter ++)
{
x = (x + 1) % 256;
y = (state[x] + y) % 256;
swap_byte(&state[x], &state[y]);
xorIndex = (state[x] + state[y]) % 256;
buffer_ptr[counter] ^= state[xorIndex];
}
key->x = x;
key->y = y;
}
static void swap_byte(unsigned char *a, unsigned char *b)
{
unsigned char swapByte;
swapByte = *a;
*a = *b;
*b = swapByte;
}
/* Dummy _des_crypt function that uses ARCFOUR with a 40 bit key */
int _arcfour_crypt(buf, len, desp)
char *buf;
int len;
struct desparams *desp;
{
struct arcfour_key arcfourk;
/*
* U.S. government anti-crypto weasels take
* note: although we are supplied with a 64 bit
* key, we're only passing 40 bits to the ARCFOUR
* encryption code. So there.
*/
prepare_key(desp->des_key, 5, &arcfourk);
arcfour(buf, len, &arcfourk);
return(DESERR_NOHWDEVICE);
}
int (*_my_crypt)(char *, int, struct desparams *) = NULL;
static void *dlhandle;
#ifndef _PATH_USRLIB
#define _PATH_USRLIB "/usr/lib"
#endif
#ifndef LIBCRYPTO
#define LIBCRYPTO "libcrypto.so.2"
#endif
void load_des(warn, libpath)
int warn;
char *libpath;
{
char dlpath[MAXPATHLEN];
if (libpath == NULL) {
snprintf(dlpath, sizeof(dlpath), "%s/%s", _PATH_USRLIB, LIBCRYPTO);
} else
snprintf(dlpath, sizeof(dlpath), "%s", libpath);
if (dlpath != NULL && (dlhandle = dlopen(dlpath, 0444)) != NULL)
_my_crypt = (int (*)())dlsym(dlhandle, "_des_crypt");
if (_my_crypt == NULL) {
if (dlhandle != NULL)
dlclose(dlhandle);
_my_crypt = &_arcfour_crypt;
if (warn) {
printf ("DES support disabled -- using ARCFOUR instead.\n");
printf ("Warning: ARCFOUR cipher is not compatible with ");
printf ("other Secure RPC implementations.\nInstall ");
printf ("the FreeBSD 'des' distribution to enable");
printf (" DES encryption.\n");
}
} else {
if (warn) {
printf ("DES support enabled\n");
printf ("Using %s shared object.\n", dlpath);
}
}
return;
}
desresp *
des_crypt_1_svc(desargs *argp, struct svc_req *rqstp)
{
static desresp result;
struct desparams dparm;
if (argp->desbuf.desbuf_len > DES_MAXDATA) {
result.stat = DESERR_BADPARAM;
return(&result);
}
bcopy(argp->des_key, dparm.des_key, 8);
bcopy(argp->des_ivec, dparm.des_ivec, 8);
dparm.des_mode = argp->des_mode;
dparm.des_dir = argp->des_dir;
#ifdef BROKEN_DES
dparm.UDES.UDES_buf = argp->desbuf.desbuf_val;
#endif
/*
* XXX This compensates for a bug in the libdes Secure RPC
* compat interface. (Actually, there are a couple.) The
* des_ecb_encrypt() routine in libdes only encrypts 8 bytes
* (64 bits) at a time. However, the Sun Secure RPC ecb_crypt()
* routine is supposed to be able to handle buffers up to 8Kbytes.
* The rpc_enc module in libdes ignores this fact and just drops
* the length parameter on the floor, encrypting only the
* first 64 bits of whatever buffer you feed it. We deal with
* this here: if we're using DES encryption, and we're using
* ECB mode, then we make a pass over the entire buffer
* ourselves. Note: the rpc_enc module incorrectly transposes
* the mode flags, so when you ask for CBC mode, you're really
* getting ECB mode.
*/
#ifdef BROKEN_DES
if (_my_crypt != &_arcfour_crypt && argp->des_mode == CBC) {
#else
if (_my_crypt != &_arcfour_crypt && argp->des_mode == ECB) {
#endif
int i;
char *dptr;
for (i = 0; i < argp->desbuf.desbuf_len / 8; i++) {
dptr = argp->desbuf.desbuf_val;
dptr += (i * 8);
#ifdef BROKEN_DES
dparm.UDES.UDES_buf = dptr;
#endif
result.stat = _my_crypt(dptr, 8, &dparm);
}
} else {
result.stat = _my_crypt(argp->desbuf.desbuf_val,
argp->desbuf.desbuf_len,
&dparm);
}
if (result.stat == DESERR_NONE || result.stat == DESERR_NOHWDEVICE) {
bcopy(dparm.des_ivec, result.des_ivec, 8);
result.desbuf.desbuf_len = argp->desbuf.desbuf_len;
result.desbuf.desbuf_val = argp->desbuf.desbuf_val;
}
return (&result);
}
