1 /* 2 * auth_time.c 3 * 4 * This module contains the private function __rpc_get_time_offset() 5 * which will return the difference in seconds between the local system's 6 * notion of time and a remote server's notion of time. This must be 7 * possible without calling any functions that may invoke the name 8 * service. (netdir_getbyxxx, getXbyY, etc). The function is used in the 9 * synchronize call of the authdes code to synchronize clocks between 10 * NIS+ clients and their servers. 11 * 12 * Note to minimize the amount of duplicate code, portions of the 13 * synchronize() function were folded into this code, and the synchronize 14 * call becomes simply a wrapper around this function. Further, if this 15 * function is called with a timehost it *DOES* recurse to the name 16 * server so don't use it in that mode if you are doing name service code. 17 * 18 * Copyright (c) 1992 Sun Microsystems Inc. 19 * All rights reserved. 20 * 21 * Side effects : 22 * When called a client handle to a RPCBIND process is created 23 * and destroyed. Two strings "netid" and "uaddr" are malloc'd 24 * and returned. The SIGALRM processing is modified only if 25 * needed to deal with TCP connections. 26 */ 27 28 //#include <sys/cdefs.h> 29 #include <wintirpc.h> 30 //#include <syslog.h> 31 #include <string.h> 32 #include <stdlib.h> 33 //#include <unistd.h> 34 //#include <netdb.h> 35 //#include <sys/signal.h> 36 #include <errno.h> 37 //#include <sys/socket.h> 38 //#include <netinet/in.h> 39 //#include <arpa/inet.h> 40 41 #include <rpc/rpc.h> 42 #include <rpc/rpc_com.h> 43 #include <rpc/rpcb_prot.h> 44 //#include <clnt_soc.h> 45 //#include <sys/select.h> 46 #undef NIS 47 #include <rpcsvc/nis.h> 48 49 50 #ifdef TESTING 51 #define msg(x) printf("ERROR: %s\n", x) 52 /* #define msg(x) syslog(LOG_ERR, "%s", x) */ 53 #else 54 #define msg(x) 55 #endif 56 57 static int saw_alarm = 0; 58 59 static void 60 alarm_hndler(s) 61 int s; 62 { 63 saw_alarm = 1; 64 return; 65 } 66 67 /* 68 * The internet time server defines the epoch to be Jan 1, 1900 69 * whereas UNIX defines it to be Jan 1, 1970. To adjust the result 70 * from internet time-service time, into UNIX time we subtract the 71 * following offset : 72 */ 73 #define NYEARS (1970 - 1900) 74 #define TOFFSET ((u_long)60*60*24*(365*NYEARS + (NYEARS/4))) 75 76 77 /* 78 * Stolen from rpc.nisd: 79 * Turn a 'universal address' into a struct sockaddr_in. 80 * Bletch. 81 */ 82 static int uaddr_to_sockaddr(uaddr, sin) 83 #ifdef foo 84 endpoint *endpt; 85 #endif 86 char *uaddr; 87 struct sockaddr_in *sin; 88 { 89 unsigned char p_bytes[2]; 90 int i; 91 unsigned long a[6]; 92 93 i = sscanf(uaddr, "%lu.%lu.%lu.%lu.%lu.%lu", &a[0], &a[1], &a[2], 94 &a[3], &a[4], &a[5]); 95 96 if (i < 6) 97 return(1); 98 99 for (i = 0; i < 4; i++) 100 sin->sin_addr.s_addr |= (a[i] & 0x000000FF) << (8 * i); 101 102 p_bytes[0] = (unsigned char)a[4] & 0x000000FF; 103 p_bytes[1] = (unsigned char)a[5] & 0x000000FF; 104 105 sin->sin_family = AF_INET; /* always */ 106 bcopy((char *)&p_bytes, (char *)&sin->sin_port, 2); 107 108 return (0); 109 } 110 111 /* 112 * free_eps() 113 * 114 * Free the strings that were strduped into the eps structure. 115 */ 116 static void 117 free_eps(eps, num) 118 endpoint eps[]; 119 int num; 120 { 121 int i; 122 123 for (i = 0; i < num; i++) { 124 free(eps[i].uaddr); 125 free(eps[i].proto); 126 free(eps[i].family); 127 } 128 return; 129 } 130 131 /* 132 * get_server() 133 * 134 * This function constructs a nis_server structure description for the 135 * indicated hostname. 136 * 137 * NOTE: There is a chance we may end up recursing here due to the 138 * fact that gethostbyname() could do an NIS search. Ideally, the 139 * NIS+ server will call __rpc_get_time_offset() with the nis_server 140 * structure already populated. 141 */ 142 static nis_server * 143 get_server(sin, host, srv, eps, maxep) 144 struct sockaddr_in *sin; 145 char *host; /* name of the time host */ 146 nis_server *srv; /* nis_server struct to use. */ 147 endpoint eps[]; /* array of endpoints */ 148 int maxep; /* max array size */ 149 { 150 char hname[256]; 151 int num_ep = 0, i; 152 struct hostent *he; 153 struct hostent dummy; 154 char *ptr[2]; 155 156 if (host == NULL && sin == NULL) 157 return (NULL); 158 159 if (sin == NULL) { 160 he = gethostbyname(host); 161 if (he == NULL) 162 return(NULL); 163 } else { 164 he = &dummy; 165 ptr[0] = (char *)&sin->sin_addr.s_addr; 166 ptr[1] = NULL; 167 dummy.h_addr_list = ptr; 168 } 169 170 /* 171 * This is lame. We go around once for TCP, then again 172 * for UDP. 173 */ 174 for (i = 0; (he->h_addr_list[i] != NULL) && (num_ep < maxep); 175 i++, num_ep++) { 176 struct in_addr *a; 177 178 a = (struct in_addr *)he->h_addr_list[i]; 179 snprintf(hname, sizeof(hname), "%s.0.111", inet_ntoa(*a)); 180 eps[num_ep].uaddr = strdup(hname); 181 eps[num_ep].family = strdup("inet"); 182 eps[num_ep].proto = strdup("tcp"); 183 } 184 185 for (i = 0; (he->h_addr_list[i] != NULL) && (num_ep < maxep); 186 i++, num_ep++) { 187 struct in_addr *a; 188 189 a = (struct in_addr *)he->h_addr_list[i]; 190 snprintf(hname, sizeof(hname), "%s.0.111", inet_ntoa(*a)); 191 eps[num_ep].uaddr = strdup(hname); 192 eps[num_ep].family = strdup("inet"); 193 eps[num_ep].proto = strdup("udp"); 194 } 195 196 srv->name = (nis_name) host; 197 srv->ep.ep_len = num_ep; 198 srv->ep.ep_val = eps; 199 srv->key_type = NIS_PK_NONE; 200 srv->pkey.n_bytes = NULL; 201 srv->pkey.n_len = 0; 202 return (srv); 203 } 204 205 /* 206 * __rpc_get_time_offset() 207 * 208 * This function uses a nis_server structure to contact the a remote 209 * machine (as named in that structure) and returns the offset in time 210 * between that machine and this one. This offset is returned in seconds 211 * and may be positive or negative. 212 * 213 * The first time through, a lot of fiddling is done with the netconfig 214 * stuff to find a suitable transport. The function is very aggressive 215 * about choosing UDP or at worst TCP if it can. This is because 216 * those transports support both the RCPBIND call and the internet 217 * time service. 218 * 219 * Once through, *uaddr is set to the universal address of 220 * the machine and *netid is set to the local netid for the transport 221 * that uaddr goes with. On the second call, the netconfig stuff 222 * is skipped and the uaddr/netid pair are used to fetch the netconfig 223 * structure and to then contact the machine for the time. 224 * 225 * td = "server" - "client" 226 */ 227 int 228 __rpc_get_time_offset(td, srv, thost, uaddr, netid) 229 struct timeval *td; /* Time difference */ 230 nis_server *srv; /* NIS Server description */ 231 char *thost; /* if no server, this is the timehost */ 232 char **uaddr; /* known universal address */ 233 struct sockaddr_in *netid; /* known network identifier */ 234 { 235 CLIENT *clnt; /* Client handle */ 236 endpoint *ep, /* useful endpoints */ 237 *useep = NULL; /* endpoint of xp */ 238 char *useua = NULL; /* uaddr of selected xp */ 239 int epl, i; /* counters */ 240 enum clnt_stat status; /* result of clnt_call */ 241 long thetime; 242 long delta; 243 int needfree = 0; 244 struct timeval tv; 245 int time_valid; 246 int udp_ep = -1, tcp_ep = -1; 247 int a1, a2, a3, a4; 248 char ut[64], ipuaddr[64]; 249 endpoint teps[32]; 250 nis_server tsrv; 251 #ifndef __REACTOS__ 252 void (*oldsig)() = NULL; /* old alarm handler */ 253 #endif 254 struct sockaddr_in sin; 255 SOCKET s = RPC_ANYSOCK; 256 socklen_t len; 257 int type = 0; 258 259 td->tv_sec = 0; 260 td->tv_usec = 0; 261 262 /* 263 * First check to see if we need to find and address for this 264 * server. 265 */ 266 if (*uaddr == NULL) { 267 if ((srv != NULL) && (thost != NULL)) { 268 msg("both timehost and srv pointer used!"); 269 return (0); 270 } 271 if (! srv) { 272 srv = get_server(netid, thost, &tsrv, teps, 32); 273 if (srv == NULL) { 274 msg("unable to contruct server data."); 275 return (0); 276 } 277 needfree = 1; /* need to free data in endpoints */ 278 } 279 280 ep = srv->ep.ep_val; 281 epl = srv->ep.ep_len; 282 283 /* Identify the TCP and UDP endpoints */ 284 for (i = 0; 285 (i < epl) && ((udp_ep == -1) || (tcp_ep == -1)); i++) { 286 if (strcasecmp(ep[i].proto, "udp") == 0) 287 udp_ep = i; 288 if (strcasecmp(ep[i].proto, "tcp") == 0) 289 tcp_ep = i; 290 } 291 292 /* Check to see if it is UDP or TCP */ 293 if (tcp_ep > -1) { 294 useep = &ep[tcp_ep]; 295 useua = ep[tcp_ep].uaddr; 296 type = SOCK_STREAM; 297 } else if (udp_ep > -1) { 298 useep = &ep[udp_ep]; 299 useua = ep[udp_ep].uaddr; 300 type = SOCK_DGRAM; 301 } 302 303 if (useep == NULL) { 304 msg("no acceptable transport endpoints."); 305 if (needfree) 306 free_eps(teps, tsrv.ep.ep_len); 307 return (0); 308 } 309 } 310 311 /* 312 * Create a sockaddr from the uaddr. 313 */ 314 if (*uaddr != NULL) 315 useua = *uaddr; 316 317 /* Fixup test for NIS+ */ 318 sscanf(useua, "%d.%d.%d.%d.", &a1, &a2, &a3, &a4); 319 sprintf(ipuaddr, "%d.%d.%d.%d.0.111", a1, a2, a3, a4); 320 useua = &ipuaddr[0]; 321 322 bzero((char *)&sin, sizeof(sin)); 323 if (uaddr_to_sockaddr(useua, &sin)) { 324 msg("unable to translate uaddr to sockaddr."); 325 if (needfree) 326 free_eps(teps, tsrv.ep.ep_len); 327 return (0); 328 } 329 330 /* 331 * Create the client handle to rpcbind. Note we always try 332 * version 3 since that is the earliest version that supports 333 * the RPCB_GETTIME call. Also it is the version that comes 334 * standard with SVR4. Since most everyone supports TCP/IP 335 * we could consider trying the rtime call first. 336 */ 337 clnt = clnttcp_create(&sin, RPCBPROG, RPCBVERS, &s, 0, 0); 338 if (clnt == NULL) { 339 msg("unable to create client handle to rpcbind."); 340 if (needfree) 341 free_eps(teps, tsrv.ep.ep_len); 342 return (0); 343 } 344 345 tv.tv_sec = 5; 346 tv.tv_usec = 0; 347 time_valid = 0; 348 status = clnt_call(clnt, RPCBPROC_GETTIME, (xdrproc_t)xdr_void, NULL, 349 (xdrproc_t)xdr_u_long, &thetime, tv); 350 /* 351 * The only error we check for is anything but success. In 352 * fact we could have seen PROGMISMATCH if talking to a 4.1 353 * machine (pmap v2) or TIMEDOUT if the net was busy. 354 */ 355 if (status == RPC_SUCCESS) 356 time_valid = 1; 357 else { 358 int save; 359 360 /* Blow away possible stale CLNT handle. */ 361 if (clnt != NULL) { 362 clnt_destroy(clnt); 363 clnt = NULL; 364 } 365 366 /* 367 * Convert PMAP address into timeservice address 368 * We take advantage of the fact that we "know" what 369 * the universal address looks like for inet transports. 370 * 371 * We also know that the internet timeservice is always 372 * listening on port 37. 373 */ 374 sscanf(useua, "%d.%d.%d.%d.", &a1, &a2, &a3, &a4); 375 sprintf(ut, "%d.%d.%d.%d.0.37", a1, a2, a3, a4); 376 377 if (uaddr_to_sockaddr(ut, &sin)) { 378 msg("cannot convert timeservice uaddr to sockaddr."); 379 goto error; 380 } 381 382 s = socket(AF_INET, type, 0); 383 if (s == INVALID_SOCKET) { 384 msg("unable to open fd to network."); 385 goto error; 386 } 387 388 /* 389 * Now depending on whether or not we're talking to 390 * UDP we set a timeout or not. 391 */ 392 if (type == SOCK_DGRAM) { 393 struct timeval timeout = { 20, 0 }; 394 struct sockaddr_in from; 395 fd_set readfds; 396 int res; 397 398 if (sendto(s, (const char *)&thetime, sizeof(thetime), 0, 399 (struct sockaddr *)&sin, sizeof(sin)) == -1) { 400 msg("udp : sendto failed."); 401 goto error; 402 } 403 do { 404 FD_ZERO(&readfds); 405 FD_SET(s, &readfds); 406 res = select(_rpc_dtablesize(), &readfds, 407 (fd_set *)NULL, (fd_set *)NULL, &timeout); 408 } while (res == SOCKET_ERROR && WSAGetLastError() == WSAEINTR); 409 if (res == SOCKET_ERROR) 410 goto error; 411 len = sizeof(from); 412 res = recvfrom(s, (char *)&thetime, sizeof(thetime), 0, 413 (struct sockaddr *)&from, &len); 414 if (res == SOCKET_ERROR) { 415 msg("recvfrom failed on udp transport."); 416 goto error; 417 } 418 time_valid = 1; 419 } else { 420 int res; 421 #ifndef _WIN32 422 oldsig = (void (*)())signal(SIGALRM, alarm_hndler); 423 saw_alarm = 0; /* global tracking the alarm */ 424 alarm(20); /* only wait 20 seconds */ 425 #else 426 saw_alarm = 0; 427 /* XXX Need Windows signal/alarm stuff here XXX */ 428 #endif 429 res = connect(s, (struct sockaddr *)&sin, sizeof(sin)); 430 if (res == SOCKET_ERROR) { 431 msg("failed to connect to tcp endpoint."); 432 goto error; 433 } 434 if (saw_alarm) { 435 msg("alarm caught it, must be unreachable."); 436 goto error; 437 } 438 // res = read(s, (char *)&thetime, sizeof(thetime)); 439 res = recv(s, (char *)&thetime, sizeof(thetime), 0); 440 if (res != sizeof(thetime)) { 441 if (saw_alarm) 442 msg("timed out TCP call."); 443 else 444 msg("wrong size of results returned"); 445 446 goto error; 447 } 448 time_valid = 1; 449 } 450 save = WSAGetLastError(); 451 (void)closesocket(s); 452 errno = save; 453 s = RPC_ANYSOCK; 454 455 if (time_valid) { 456 thetime = ntohl(thetime); 457 thetime = thetime - TOFFSET; /* adjust to UNIX time */ 458 } else 459 thetime = 0; 460 } 461 462 gettimeofday(&tv, 0); 463 464 error: 465 /* 466 * clean up our allocated data structures. 467 */ 468 469 if (s != RPC_ANYSOCK) 470 (void)closesocket(s); 471 472 if (clnt != NULL) 473 clnt_destroy(clnt); 474 475 #ifdef _WIN32 476 /* XXX Need Windows signal/alarm stuff here XXX */ 477 #else 478 alarm(0); /* reset that alarm if its outstanding */ 479 if (oldsig) { 480 signal(SIGALRM, oldsig); 481 } 482 #endif 483 484 /* 485 * note, don't free uaddr strings until after we've made a 486 * copy of them. 487 */ 488 if (time_valid) { 489 if (*uaddr == NULL) 490 *uaddr = strdup(useua); 491 492 /* Round to the nearest second */ 493 tv.tv_sec += (tv.tv_sec > 500000) ? 1 : 0; 494 delta = (thetime > tv.tv_sec) ? thetime - tv.tv_sec : 495 tv.tv_sec - thetime; 496 td->tv_sec = (thetime < tv.tv_sec) ? - delta : delta; 497 td->tv_usec = 0; 498 } else { 499 msg("unable to get the server's time."); 500 } 501 502 if (needfree) 503 free_eps(teps, tsrv.ep.ep_len); 504 505 return (time_valid); 506 } 507