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
alarm_hndler(s)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
free_eps(eps,num)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 *
get_server(sin,host,srv,eps,maxep)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
__rpc_get_time_offset(td,srv,thost,uaddr,netid)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