1 2 /* 3 * Copyright (c) 1988 by Sun Microsystems, Inc. 4 */ 5 6 /*- 7 * Copyright (c) 2009, Sun Microsystems, Inc. 8 * All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions are met: 12 * - Redistributions of source code must retain the above copyright notice, 13 * this list of conditions and the following disclaimer. 14 * - Redistributions in binary form must reproduce the above copyright notice, 15 * this list of conditions and the following disclaimer in the documentation 16 * and/or other materials provided with the distribution. 17 * - Neither the name of Sun Microsystems, Inc. nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 22 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 25 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 31 * POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 /* 35 * svcauth_des.c, server-side des authentication 36 * 37 * We insure for the service the following: 38 * (1) The timestamp microseconds do not exceed 1 million. 39 * (2) The timestamp plus the window is less than the current time. 40 * (3) The timestamp is not less than the one previously 41 * seen in the current session. 42 * 43 * It is up to the server to determine if the window size is 44 * too small . 45 * 46 */ 47 48 #include "namespace.h" 49 #include "reentrant.h" 50 #include <string.h> 51 #include <stdlib.h> 52 #include <stdio.h> 53 #include <unistd.h> 54 #include <rpc/des_crypt.h> 55 #include <sys/param.h> 56 #include <netinet/in.h> 57 #include <rpc/types.h> 58 #include <rpc/xdr.h> 59 #include <rpc/auth.h> 60 #include <rpc/auth_des.h> 61 #include <rpc/svc.h> 62 #include <rpc/rpc_msg.h> 63 #include <rpc/svc_auth.h> 64 #include "libc_private.h" 65 66 #if defined(LIBC_SCCS) && !defined(lint) 67 static char sccsid[] = "@(#)svcauth_des.c 2.3 89/07/11 4.0 RPCSRC; from 1.15 88/02/08 SMI"; 68 #endif 69 #include <sys/cdefs.h> 70 __FBSDID("$FreeBSD$"); 71 72 extern int key_decryptsession_pk(const char *, netobj *, des_block *); 73 74 #define debug(msg) printf("svcauth_des: %s\n", msg) 75 76 #define USEC_PER_SEC ((u_long) 1000000L) 77 #define BEFORE(t1, t2) timercmp(t1, t2, <) 78 79 /* 80 * LRU cache of conversation keys and some other useful items. 81 */ 82 #define AUTHDES_CACHESZ 64 83 struct cache_entry { 84 des_block key; /* conversation key */ 85 char *rname; /* client's name */ 86 u_int window; /* credential lifetime window */ 87 struct timeval laststamp; /* detect replays of creds */ 88 char *localcred; /* generic local credential */ 89 }; 90 static struct cache_entry *authdes_cache/* [AUTHDES_CACHESZ] */; 91 static short *authdes_lru/* [AUTHDES_CACHESZ] */; 92 93 static void cache_init(void); /* initialize the cache */ 94 static short cache_spot(des_block *, char *, struct timeval *); /* find an entry in the cache */ 95 static void cache_ref(short sid); /* note that sid was ref'd */ 96 97 static void invalidate(char *); /* invalidate entry in cache */ 98 99 /* 100 * cache statistics 101 */ 102 static struct { 103 u_long ncachehits; /* times cache hit, and is not replay */ 104 u_long ncachereplays; /* times cache hit, and is replay */ 105 u_long ncachemisses; /* times cache missed */ 106 } svcauthdes_stats; 107 108 /* 109 * Service side authenticator for AUTH_DES 110 */ 111 enum auth_stat 112 _svcauth_des(struct svc_req *rqst, struct rpc_msg *msg) 113 { 114 115 long *ixdr; 116 des_block cryptbuf[2]; 117 struct authdes_cred *cred; 118 struct authdes_verf verf; 119 int status; 120 struct cache_entry *entry; 121 short sid = 0; 122 des_block *sessionkey; 123 des_block ivec; 124 u_int window; 125 struct timeval timestamp; 126 u_long namelen; 127 struct area { 128 struct authdes_cred area_cred; 129 char area_netname[MAXNETNAMELEN+1]; 130 } *area; 131 132 if (authdes_cache == NULL) { 133 cache_init(); 134 } 135 136 area = (struct area *)rqst->rq_clntcred; 137 cred = (struct authdes_cred *)&area->area_cred; 138 139 /* 140 * Get the credential 141 */ 142 ixdr = (long *)msg->rm_call.cb_cred.oa_base; 143 cred->adc_namekind = IXDR_GET_ENUM(ixdr, enum authdes_namekind); 144 switch (cred->adc_namekind) { 145 case ADN_FULLNAME: 146 namelen = IXDR_GET_U_LONG(ixdr); 147 if (namelen > MAXNETNAMELEN) { 148 return (AUTH_BADCRED); 149 } 150 cred->adc_fullname.name = area->area_netname; 151 bcopy((char *)ixdr, cred->adc_fullname.name, 152 (u_int)namelen); 153 cred->adc_fullname.name[namelen] = 0; 154 ixdr += (RNDUP(namelen) / BYTES_PER_XDR_UNIT); 155 cred->adc_fullname.key.key.high = (u_long)*ixdr++; 156 cred->adc_fullname.key.key.low = (u_long)*ixdr++; 157 cred->adc_fullname.window = (u_long)*ixdr++; 158 break; 159 case ADN_NICKNAME: 160 cred->adc_nickname = (u_long)*ixdr++; 161 break; 162 default: 163 return (AUTH_BADCRED); 164 } 165 166 /* 167 * Get the verifier 168 */ 169 ixdr = (long *)msg->rm_call.cb_verf.oa_base; 170 verf.adv_xtimestamp.key.high = (u_long)*ixdr++; 171 verf.adv_xtimestamp.key.low = (u_long)*ixdr++; 172 verf.adv_int_u = (u_long)*ixdr++; 173 174 175 /* 176 * Get the conversation key 177 */ 178 if (cred->adc_namekind == ADN_FULLNAME) { 179 netobj pkey; 180 char pkey_data[1024]; 181 182 sessionkey = &cred->adc_fullname.key; 183 if (! getpublickey(cred->adc_fullname.name, pkey_data)) { 184 debug("getpublickey"); 185 return(AUTH_BADCRED); 186 } 187 pkey.n_bytes = pkey_data; 188 pkey.n_len = strlen(pkey_data) + 1; 189 if (key_decryptsession_pk(cred->adc_fullname.name, &pkey, 190 sessionkey) < 0) { 191 debug("decryptsessionkey"); 192 return (AUTH_BADCRED); /* key not found */ 193 } 194 } else { /* ADN_NICKNAME */ 195 sid = (short)cred->adc_nickname; 196 if (sid < 0 || sid >= AUTHDES_CACHESZ) { 197 debug("bad nickname"); 198 return (AUTH_BADCRED); /* garbled credential */ 199 } 200 sessionkey = &authdes_cache[sid].key; 201 } 202 203 204 /* 205 * Decrypt the timestamp 206 */ 207 cryptbuf[0] = verf.adv_xtimestamp; 208 if (cred->adc_namekind == ADN_FULLNAME) { 209 cryptbuf[1].key.high = cred->adc_fullname.window; 210 cryptbuf[1].key.low = verf.adv_winverf; 211 ivec.key.high = ivec.key.low = 0; 212 status = cbc_crypt((char *)sessionkey, (char *)cryptbuf, 213 2*sizeof(des_block), DES_DECRYPT | DES_HW, 214 (char *)&ivec); 215 } else { 216 status = ecb_crypt((char *)sessionkey, (char *)cryptbuf, 217 sizeof(des_block), DES_DECRYPT | DES_HW); 218 } 219 if (DES_FAILED(status)) { 220 debug("decryption failure"); 221 return (AUTH_FAILED); /* system error */ 222 } 223 224 /* 225 * XDR the decrypted timestamp 226 */ 227 ixdr = (long *)cryptbuf; 228 timestamp.tv_sec = IXDR_GET_LONG(ixdr); 229 timestamp.tv_usec = IXDR_GET_LONG(ixdr); 230 231 /* 232 * Check for valid credentials and verifiers. 233 * They could be invalid because the key was flushed 234 * out of the cache, and so a new session should begin. 235 * Be sure and send AUTH_REJECTED{CRED, VERF} if this is the case. 236 */ 237 { 238 struct timeval current; 239 int nick; 240 int winverf; 241 242 if (cred->adc_namekind == ADN_FULLNAME) { 243 window = IXDR_GET_U_LONG(ixdr); 244 winverf = IXDR_GET_U_LONG(ixdr); 245 if (winverf != window - 1) { 246 debug("window verifier mismatch"); 247 return (AUTH_BADCRED); /* garbled credential */ 248 } 249 sid = cache_spot(sessionkey, cred->adc_fullname.name, 250 ×tamp); 251 if (sid < 0) { 252 debug("replayed credential"); 253 return (AUTH_REJECTEDCRED); /* replay */ 254 } 255 nick = 0; 256 } else { /* ADN_NICKNAME */ 257 window = authdes_cache[sid].window; 258 nick = 1; 259 } 260 261 if ((u_long)timestamp.tv_usec >= USEC_PER_SEC) { 262 debug("invalid usecs"); 263 /* cached out (bad key), or garbled verifier */ 264 return (nick ? AUTH_REJECTEDVERF : AUTH_BADVERF); 265 } 266 if (nick && BEFORE(×tamp, 267 &authdes_cache[sid].laststamp)) { 268 debug("timestamp before last seen"); 269 return (AUTH_REJECTEDVERF); /* replay */ 270 } 271 (void)gettimeofday(¤t, NULL); 272 current.tv_sec -= window; /* allow for expiration */ 273 if (!BEFORE(¤t, ×tamp)) { 274 debug("timestamp expired"); 275 /* replay, or garbled credential */ 276 return (nick ? AUTH_REJECTEDVERF : AUTH_BADCRED); 277 } 278 } 279 280 /* 281 * Set up the reply verifier 282 */ 283 verf.adv_nickname = (u_long)sid; 284 285 /* 286 * xdr the timestamp before encrypting 287 */ 288 ixdr = (long *)cryptbuf; 289 IXDR_PUT_LONG(ixdr, timestamp.tv_sec - 1); 290 IXDR_PUT_LONG(ixdr, timestamp.tv_usec); 291 292 /* 293 * encrypt the timestamp 294 */ 295 status = ecb_crypt((char *)sessionkey, (char *)cryptbuf, 296 sizeof(des_block), DES_ENCRYPT | DES_HW); 297 if (DES_FAILED(status)) { 298 debug("encryption failure"); 299 return (AUTH_FAILED); /* system error */ 300 } 301 verf.adv_xtimestamp = cryptbuf[0]; 302 303 /* 304 * Serialize the reply verifier, and update rqst 305 */ 306 ixdr = (long *)msg->rm_call.cb_verf.oa_base; 307 *ixdr++ = (long)verf.adv_xtimestamp.key.high; 308 *ixdr++ = (long)verf.adv_xtimestamp.key.low; 309 *ixdr++ = (long)verf.adv_int_u; 310 311 rqst->rq_xprt->xp_verf.oa_flavor = AUTH_DES; 312 rqst->rq_xprt->xp_verf.oa_base = msg->rm_call.cb_verf.oa_base; 313 rqst->rq_xprt->xp_verf.oa_length = 314 (char *)ixdr - msg->rm_call.cb_verf.oa_base; 315 316 /* 317 * We succeeded, commit the data to the cache now and 318 * finish cooking the credential. 319 */ 320 entry = &authdes_cache[sid]; 321 entry->laststamp = timestamp; 322 cache_ref(sid); 323 if (cred->adc_namekind == ADN_FULLNAME) { 324 cred->adc_fullname.window = window; 325 cred->adc_nickname = (u_long)sid; /* save nickname */ 326 if (entry->rname != NULL) { 327 mem_free(entry->rname, strlen(entry->rname) + 1); 328 } 329 entry->rname = (char *)mem_alloc((u_int)strlen(cred->adc_fullname.name) 330 + 1); 331 if (entry->rname != NULL) { 332 (void) strcpy(entry->rname, cred->adc_fullname.name); 333 } else { 334 debug("out of memory"); 335 } 336 entry->key = *sessionkey; 337 entry->window = window; 338 invalidate(entry->localcred); /* mark any cached cred invalid */ 339 } else { /* ADN_NICKNAME */ 340 /* 341 * nicknames are cooked into fullnames 342 */ 343 cred->adc_namekind = ADN_FULLNAME; 344 cred->adc_fullname.name = entry->rname; 345 cred->adc_fullname.key = entry->key; 346 cred->adc_fullname.window = entry->window; 347 } 348 return (AUTH_OK); /* we made it!*/ 349 } 350 351 352 /* 353 * Initialize the cache 354 */ 355 static void 356 cache_init(void) 357 { 358 int i; 359 360 authdes_cache = (struct cache_entry *) 361 mem_alloc(sizeof(struct cache_entry) * AUTHDES_CACHESZ); 362 bzero((char *)authdes_cache, 363 sizeof(struct cache_entry) * AUTHDES_CACHESZ); 364 365 authdes_lru = (short *)mem_alloc(sizeof(short) * AUTHDES_CACHESZ); 366 /* 367 * Initialize the lru list 368 */ 369 for (i = 0; i < AUTHDES_CACHESZ; i++) { 370 authdes_lru[i] = i; 371 } 372 } 373 374 375 /* 376 * Find the lru victim 377 */ 378 static short 379 cache_victim(void) 380 { 381 return (authdes_lru[AUTHDES_CACHESZ-1]); 382 } 383 384 /* 385 * Note that sid was referenced 386 */ 387 static void 388 cache_ref(short sid) 389 { 390 int i; 391 short curr; 392 short prev; 393 394 prev = authdes_lru[0]; 395 authdes_lru[0] = sid; 396 for (i = 1; prev != sid; i++) { 397 curr = authdes_lru[i]; 398 authdes_lru[i] = prev; 399 prev = curr; 400 } 401 } 402 403 404 /* 405 * Find a spot in the cache for a credential containing 406 * the items given. Return -1 if a replay is detected, otherwise 407 * return the spot in the cache. 408 */ 409 static short 410 cache_spot(des_block *key, char *name, struct timeval *timestamp) 411 { 412 struct cache_entry *cp; 413 int i; 414 u_long hi; 415 416 hi = key->key.high; 417 for (cp = authdes_cache, i = 0; i < AUTHDES_CACHESZ; i++, cp++) { 418 if (cp->key.key.high == hi && 419 cp->key.key.low == key->key.low && 420 cp->rname != NULL && 421 bcmp(cp->rname, name, strlen(name) + 1) == 0) { 422 if (BEFORE(timestamp, &cp->laststamp)) { 423 svcauthdes_stats.ncachereplays++; 424 return (-1); /* replay */ 425 } 426 svcauthdes_stats.ncachehits++; 427 return (i); /* refresh */ 428 } 429 } 430 svcauthdes_stats.ncachemisses++; 431 return (cache_victim()); /* new credential */ 432 } 433 434 435 #if (defined(sun) || defined(vax) || defined(__FreeBSD__)) 436 /* 437 * Local credential handling stuff. 438 * NOTE: bsd unix dependent. 439 * Other operating systems should put something else here. 440 */ 441 #define UNKNOWN -2 /* grouplen, if cached cred is unknown user */ 442 #define INVALID -1 /* grouplen, if cache entry is invalid */ 443 444 struct bsdcred { 445 uid_t uid; /* cached uid */ 446 gid_t gid; /* cached gid */ 447 int grouplen; /* length of cached groups */ 448 gid_t groups[NGRPS]; /* cached groups */ 449 }; 450 451 /* 452 * Map a des credential into a unix cred. 453 * We cache the credential here so the application does 454 * not have to make an rpc call every time to interpret 455 * the credential. 456 */ 457 int 458 authdes_getucred(struct authdes_cred *adc, uid_t *uid, gid_t *gid, 459 int *grouplen, gid_t *groups) 460 { 461 unsigned sid; 462 int i; 463 uid_t i_uid; 464 gid_t i_gid; 465 int i_grouplen; 466 struct bsdcred *cred; 467 468 sid = adc->adc_nickname; 469 if (sid >= AUTHDES_CACHESZ) { 470 debug("invalid nickname"); 471 return (0); 472 } 473 cred = (struct bsdcred *)authdes_cache[sid].localcred; 474 if (cred == NULL) { 475 cred = (struct bsdcred *)mem_alloc(sizeof(struct bsdcred)); 476 authdes_cache[sid].localcred = (char *)cred; 477 cred->grouplen = INVALID; 478 } 479 if (cred->grouplen == INVALID) { 480 /* 481 * not in cache: lookup 482 */ 483 if (!netname2user(adc->adc_fullname.name, &i_uid, &i_gid, 484 &i_grouplen, groups)) 485 { 486 debug("unknown netname"); 487 cred->grouplen = UNKNOWN; /* mark as lookup up, but not found */ 488 return (0); 489 } 490 debug("missed ucred cache"); 491 *uid = cred->uid = i_uid; 492 *gid = cred->gid = i_gid; 493 *grouplen = cred->grouplen = i_grouplen; 494 for (i = i_grouplen - 1; i >= 0; i--) { 495 cred->groups[i] = groups[i]; /* int to short */ 496 } 497 return (1); 498 } else if (cred->grouplen == UNKNOWN) { 499 /* 500 * Already lookup up, but no match found 501 */ 502 return (0); 503 } 504 505 /* 506 * cached credentials 507 */ 508 *uid = cred->uid; 509 *gid = cred->gid; 510 *grouplen = cred->grouplen; 511 for (i = cred->grouplen - 1; i >= 0; i--) { 512 groups[i] = cred->groups[i]; /* short to int */ 513 } 514 return (1); 515 } 516 517 static void 518 invalidate(char *cred) 519 { 520 if (cred == NULL) { 521 return; 522 } 523 ((struct bsdcred *)cred)->grouplen = INVALID; 524 } 525 #endif 526 527