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Diffstat (limited to 'usr.sbin/keyserv/crypt_server.c')
| -rw-r--r-- | usr.sbin/keyserv/crypt_server.c | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/usr.sbin/keyserv/crypt_server.c b/usr.sbin/keyserv/crypt_server.c new file mode 100644 index 0000000..b4c6036 --- /dev/null +++ b/usr.sbin/keyserv/crypt_server.c @@ -0,0 +1,276 @@ +/* + * 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 == CBC_DES) ? CBC : ECB; + dparm.des_dir = (argp->des_dir == ENCRYPT_DES) ? ENCRYPT : DECRYPT; +#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); +} |
