1 /* 2 * Copyright (c) 1996 3 * Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by Bill Paul. 16 * 4. Neither the name of the author nor the names of any co-contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL Bill Paul OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * $FreeBSD: src/usr.sbin/keyserv/crypt_server.c,v 1.6.2.1 2001/07/19 04:21:20 kris Exp $ 33 * $DragonFly: src/usr.sbin/keyserv/crypt_server.c,v 1.5 2004/03/20 16:27:42 drhodus Exp $ 34 */ 35 36 #include <sys/types.h> 37 #include <sys/param.h> 38 #include <dirent.h> 39 #include <dlfcn.h> 40 #include <err.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <rpc/des_crypt.h> 45 #include <rpc/des.h> 46 #include "crypt.h" 47 48 /* 49 * The U.S. government stupidly believes that a) it can keep strong 50 * crypto code a secret and b) that doing so somehow protects national 51 * interests. It's wrong on both counts, but until it listens to reason 52 * we have to make certain compromises so it doesn't have an excuse to 53 * throw us in federal prison. 54 * 55 * Consequently, the core OS ships without DES support, and keyserv 56 * defaults to using ARCFOUR with only a 40 bit key, just like nutscrape. 57 * This breaks compatibility with Secure RPC on other systems, but it 58 * allows Secure RPC to work between FreeBSD systems that don't have the 59 * DES package installed without throwing security totally out the window. 60 * 61 * In order to avoid having to supply two versions of keyserv (one with 62 * DES and one without), we use dlopen() and friends to load libdes.so 63 * into our address space at runtime. We check for the presence of 64 * /usr/lib/libdes.so.3.0 at startup and load it if we find it. If we 65 * can't find it, or the __des_crypt symbol doesn't exist, we fall back 66 * to the ARCFOUR encryption code. The user can specify another path using 67 * the -p flag. 68 */ 69 70 /* arcfour.h */ 71 typedef struct arcfour_key 72 { 73 unsigned char state[256]; 74 unsigned char x; 75 unsigned char y; 76 } arcfour_key; 77 78 static void prepare_key(unsigned char *key_data_ptr,int key_data_len, 79 arcfour_key *key); 80 static void arcfour(unsigned char *buffer_ptr,int buffer_len,arcfour_key * key); 81 static void swap_byte(unsigned char *a, unsigned char *b); 82 83 static void prepare_key(unsigned char *key_data_ptr, int key_data_len, 84 arcfour_key *key) 85 { 86 unsigned char index1; 87 unsigned char index2; 88 unsigned char* state; 89 short counter; 90 91 state = &key->state[0]; 92 for(counter = 0; counter < 256; counter++) 93 state[counter] = counter; 94 key->x = 0; 95 key->y = 0; 96 index1 = 0; 97 index2 = 0; 98 for(counter = 0; counter < 256; counter++) 99 { 100 index2 = (key_data_ptr[index1] + state[counter] + 101 index2) % 256; 102 swap_byte(&state[counter], &state[index2]); 103 104 index1 = (index1 + 1) % key_data_len; 105 } 106 } 107 108 static void arcfour(unsigned char *buffer_ptr, int buffer_len, arcfour_key *key) 109 { 110 unsigned char x; 111 unsigned char y; 112 unsigned char* state; 113 unsigned char xorIndex; 114 short counter; 115 116 x = key->x; 117 y = key->y; 118 119 state = &key->state[0]; 120 for(counter = 0; counter < buffer_len; counter ++) 121 { 122 x = (x + 1) % 256; 123 y = (state[x] + y) % 256; 124 swap_byte(&state[x], &state[y]); 125 126 xorIndex = (state[x] + state[y]) % 256; 127 128 buffer_ptr[counter] ^= state[xorIndex]; 129 } 130 key->x = x; 131 key->y = y; 132 } 133 134 static void swap_byte(unsigned char *a, unsigned char *b) 135 { 136 unsigned char swapByte; 137 138 swapByte = *a; 139 *a = *b; 140 *b = swapByte; 141 } 142 143 /* Dummy _des_crypt function that uses ARCFOUR with a 40 bit key */ 144 int _arcfour_crypt(char *buf, int len, struct desparams *desp) 145 { 146 struct arcfour_key arcfourk; 147 148 /* 149 * U.S. government anti-crypto weasels take 150 * note: although we are supplied with a 64 bit 151 * key, we're only passing 40 bits to the ARCFOUR 152 * encryption code. So there. 153 */ 154 prepare_key(desp->des_key, 5, &arcfourk); 155 arcfour(buf, len, &arcfourk); 156 157 return(DESERR_NOHWDEVICE); 158 } 159 160 int (*_my_crypt)(char *, int, struct desparams *) = NULL; 161 162 static void *dlhandle; 163 164 #ifndef _PATH_USRLIB 165 #define _PATH_USRLIB "/usr/lib" 166 #endif 167 168 #ifndef LIBCRYPTO 169 #define LIBCRYPTO "libcrypto.so.1" 170 #endif 171 172 void load_des(int warn, char *libpath) 173 { 174 char dlpath[MAXPATHLEN]; 175 176 if (libpath == NULL) { 177 snprintf(dlpath, sizeof(dlpath), "%s/%s", _PATH_USRLIB, LIBCRYPTO); 178 } else 179 snprintf(dlpath, sizeof(dlpath), "%s", libpath); 180 181 if (dlpath != NULL && (dlhandle = dlopen(dlpath, 0444)) != NULL) 182 _my_crypt = (int (*)())dlsym(dlhandle, "_des_crypt"); 183 184 if (_my_crypt == NULL) { 185 if (dlhandle != NULL) 186 dlclose(dlhandle); 187 _my_crypt = &_arcfour_crypt; 188 if (warn) { 189 printf ("DES support disabled -- using ARCFOUR instead.\n"); 190 printf ("Warning: ARCFOUR cipher is not compatible with "); 191 printf ("other Secure RPC implementations.\nInstall "); 192 printf ("the FreeBSD 'des' distribution to enable"); 193 printf (" DES encryption.\n"); 194 } 195 } else { 196 if (warn) { 197 printf ("DES support enabled\n"); 198 printf ("Using %s shared object.\n", dlpath); 199 } 200 } 201 202 return; 203 } 204 205 desresp * 206 des_crypt_1_svc(desargs *argp, struct svc_req *rqstp) 207 { 208 static desresp result; 209 struct desparams dparm; 210 211 if (argp->desbuf.desbuf_len > DES_MAXDATA) { 212 result.stat = DESERR_BADPARAM; 213 return(&result); 214 } 215 216 217 bcopy(argp->des_key, dparm.des_key, 8); 218 bcopy(argp->des_ivec, dparm.des_ivec, 8); 219 dparm.des_mode = argp->des_mode; 220 dparm.des_dir = argp->des_dir; 221 #ifdef BROKEN_DES 222 dparm.UDES.UDES_buf = argp->desbuf.desbuf_val; 223 #endif 224 225 /* 226 * XXX This compensates for a bug in the libdes Secure RPC 227 * compat interface. (Actually, there are a couple.) The 228 * des_ecb_encrypt() routine in libdes only encrypts 8 bytes 229 * (64 bits) at a time. However, the Sun Secure RPC ecb_crypt() 230 * routine is supposed to be able to handle buffers up to 8Kbytes. 231 * The rpc_enc module in libdes ignores this fact and just drops 232 * the length parameter on the floor, encrypting only the 233 * first 64 bits of whatever buffer you feed it. We deal with 234 * this here: if we're using DES encryption, and we're using 235 * ECB mode, then we make a pass over the entire buffer 236 * ourselves. Note: the rpc_enc module incorrectly transposes 237 * the mode flags, so when you ask for CBC mode, you're really 238 * getting ECB mode. 239 */ 240 #ifdef BROKEN_DES 241 if (_my_crypt != &_arcfour_crypt && argp->des_mode == CBC) { 242 #else 243 if (_my_crypt != &_arcfour_crypt && argp->des_mode == ECB) { 244 #endif 245 int i; 246 char *dptr; 247 248 for (i = 0; i < argp->desbuf.desbuf_len / 8; i++) { 249 dptr = argp->desbuf.desbuf_val; 250 dptr += (i * 8); 251 #ifdef BROKEN_DES 252 dparm.UDES.UDES_buf = dptr; 253 #endif 254 result.stat = _my_crypt(dptr, 8, &dparm); 255 } 256 } else { 257 result.stat = _my_crypt(argp->desbuf.desbuf_val, 258 argp->desbuf.desbuf_len, 259 &dparm); 260 } 261 262 if (result.stat == DESERR_NONE || result.stat == DESERR_NOHWDEVICE) { 263 bcopy(dparm.des_ivec, result.des_ivec, 8); 264 result.desbuf.desbuf_len = argp->desbuf.desbuf_len; 265 result.desbuf.desbuf_val = argp->desbuf.desbuf_val; 266 } 267 268 return (&result); 269 } 270