File: auth_time.c

package info (click to toggle)
libtirpc 0.2.5-1%2Bdeb8u1
  • links: PTS
  • area: main
  • in suites: jessie
  • size: 3,208 kB
  • ctags: 2,619
  • sloc: ansic: 17,637; sh: 11,080; makefile: 94
file content (493 lines) | stat: -rw-r--r-- 12,520 bytes parent folder | download | duplicates (5)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
/*
 *	auth_time.c
 *
 * This module contains the private function __rpc_get_time_offset()
 * which will return the difference in seconds between the local system's
 * notion of time and a remote server's notion of time. This must be
 * possible without calling any functions that may invoke the name
 * service. (netdir_getbyxxx, getXbyY, etc). The function is used in the
 * synchronize call of the authdes code to synchronize clocks between
 * NIS+ clients and their servers.
 *
 * Note to minimize the amount of duplicate code, portions of the
 * synchronize() function were folded into this code, and the synchronize
 * call becomes simply a wrapper around this function. Further, if this
 * function is called with a timehost it *DOES* recurse to the name
 * server so don't use it in that mode if you are doing name service code.
 *
 *	Copyright (c) 1992 Sun Microsystems Inc.
 *	All rights reserved.
 *
 * Side effects :
 *	When called a client handle to a RPCBIND process is created
 *	and destroyed. Two strings "netid" and "uaddr" are malloc'd
 *	and returned. The SIGALRM processing is modified only if
 *	needed to deal with TCP connections.
 */

#include <sys/cdefs.h>
#include <stdio.h>
#include <syslog.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <netdb.h>
#include <sys/signal.h>
#include <sys/errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <rpc/rpc.h>
#include <rpc/rpc_com.h>
#include <rpc/rpcb_prot.h>
//#include <clnt_soc.h>
#include <sys/select.h>
#undef NIS
#include <rpcsvc/nis.h>


#ifdef TESTING
#define	msg(x)	printf("ERROR: %s\n", x)
/* #define msg(x) syslog(LOG_ERR, "%s", x) */
#else
#define	msg(x)
#endif

static int saw_alarm = 0;

static void
alarm_hndler(s)
	int	s;
{
	saw_alarm = 1;
	return;
}

/*
 * The internet time server defines the epoch to be Jan 1, 1900
 * whereas UNIX defines it to be Jan 1, 1970. To adjust the result
 * from internet time-service time, into UNIX time we subtract the
 * following offset :
 */
#define	NYEARS	(1970 - 1900)
#define	TOFFSET ((u_long)60*60*24*(365*NYEARS + (NYEARS/4)))


/*
 * Stolen from rpc.nisd:
 * Turn a 'universal address' into a struct sockaddr_in.
 * Bletch.
 */
static int uaddr_to_sockaddr(uaddr, sin)
#ifdef foo
	endpoint		*endpt;
#endif
	char			*uaddr;
	struct sockaddr_in	*sin;
{
	unsigned char		p_bytes[2];
	int			i;
	unsigned long		a[6];

	i = sscanf(uaddr, "%lu.%lu.%lu.%lu.%lu.%lu", &a[0], &a[1], &a[2],
						&a[3], &a[4], &a[5]);

	if (i < 6)
		return(1);

	for (i = 0; i < 4; i++)
		sin->sin_addr.s_addr |= (a[i] & 0x000000FF) << (8 * i);

	p_bytes[0] = (unsigned char)a[4] & 0x000000FF;
	p_bytes[1] = (unsigned char)a[5] & 0x000000FF;

	sin->sin_family = AF_INET; /* always */
	bcopy((char *)&p_bytes, (char *)&sin->sin_port, 2);

	return (0);
}

/*
 * free_eps()
 *
 * Free the strings that were strduped into the eps structure.
 */
static void
free_eps(eps, num)
	endpoint	eps[];
	int		num;
{
	int		i;

	for (i = 0; i < num; i++) {
		free(eps[i].uaddr);
		free(eps[i].proto);
		free(eps[i].family);
	}
	return;
}

/*
 * get_server()
 *
 * This function constructs a nis_server structure description for the
 * indicated hostname.
 *
 * NOTE: There is a chance we may end up recursing here due to the
 * fact that gethostbyname() could do an NIS search. Ideally, the
 * NIS+ server will call __rpc_get_time_offset() with the nis_server
 * structure already populated.
 */
static nis_server *
get_server(sin, host, srv, eps, maxep)
	struct sockaddr_in *sin;
	char		*host;	/* name of the time host	*/
	nis_server	*srv;	/* nis_server struct to use.	*/
	endpoint	eps[];	/* array of endpoints		*/
	int		maxep;	/* max array size		*/
{
	char			hname[256];
	int			num_ep = 0, i;
	struct hostent		*he;
	struct hostent		dummy;
	char			*ptr[2];

	if (host == NULL && sin == NULL)
		return (NULL);

	if (sin == NULL) {
		he = gethostbyname(host);
		if (he == NULL)
			return(NULL);
	} else {
		he = &dummy;
		ptr[0] = (char *)&sin->sin_addr.s_addr;
		ptr[1] = NULL;
		dummy.h_addr_list = ptr;
	}

	/*
	 * This is lame. We go around once for TCP, then again
	 * for UDP.
	 */
	for (i = 0; (he->h_addr_list[i] != NULL) && (num_ep < maxep);
						i++, num_ep++) {
		struct in_addr *a;

		a = (struct in_addr *)he->h_addr_list[i];
		snprintf(hname, sizeof(hname), "%s.0.111", inet_ntoa(*a));
		eps[num_ep].uaddr = strdup(hname);
		eps[num_ep].family = strdup("inet");
		eps[num_ep].proto =  strdup("tcp");
	}

	for (i = 0; (he->h_addr_list[i] != NULL) && (num_ep < maxep);
						i++, num_ep++) {
		struct in_addr *a;

		a = (struct in_addr *)he->h_addr_list[i];
		snprintf(hname, sizeof(hname), "%s.0.111", inet_ntoa(*a));
		eps[num_ep].uaddr = strdup(hname);
		eps[num_ep].family = strdup("inet");
		eps[num_ep].proto =  strdup("udp");
	}

	srv->name = (nis_name) host;
	srv->ep.ep_len = num_ep;
	srv->ep.ep_val = eps;
	srv->key_type = NIS_PK_NONE;
	srv->pkey.n_bytes = NULL;
	srv->pkey.n_len = 0;
	return (srv);
}

/*
 * __rpc_get_time_offset()
 *
 * This function uses a nis_server structure to contact the a remote
 * machine (as named in that structure) and returns the offset in time
 * between that machine and this one. This offset is returned in seconds
 * and may be positive or negative.
 *
 * The first time through, a lot of fiddling is done with the netconfig
 * stuff to find a suitable transport. The function is very aggressive
 * about choosing UDP or at worst TCP if it can. This is because
 * those transports support both the RCPBIND call and the internet
 * time service.
 *
 * Once through, *uaddr is set to the universal address of
 * the machine and *netid is set to the local netid for the transport
 * that uaddr goes with. On the second call, the netconfig stuff
 * is skipped and the uaddr/netid pair are used to fetch the netconfig
 * structure and to then contact the machine for the time.
 *
 * td = "server" - "client"
 */
int
__rpc_get_time_offset(td, srv, thost, uaddr, netid)
	struct timeval	*td;	 /* Time difference			*/
	nis_server	*srv;	 /* NIS Server description 		*/
	char		*thost;	 /* if no server, this is the timehost	*/
	char		**uaddr; /* known universal address		*/
	struct sockaddr_in *netid; /* known network identifier		*/
{
	CLIENT			*clnt; 		/* Client handle 	*/
	endpoint		*ep,		/* useful endpoints	*/
				*useep = NULL;	/* endpoint of xp	*/
	char			*useua = NULL;	/* uaddr of selected xp	*/
	int			epl, i;		/* counters		*/
	enum clnt_stat		status;		/* result of clnt_call	*/
	u_long			thetime, delta;
	int			needfree = 0;
	struct timeval		tv;
	int			time_valid;
	int			udp_ep = -1, tcp_ep = -1;
	int			a1, a2, a3, a4;
	char			ut[64], ipuaddr[64];
	endpoint		teps[32];
	nis_server		tsrv;
	void			(*oldsig)() = NULL; /* old alarm handler */
	struct sockaddr_in	sin;
	int			s = RPC_ANYSOCK;
	socklen_t len;
	int			type = 0;

	td->tv_sec = 0;
	td->tv_usec = 0;

	/*
	 * First check to see if we need to find and address for this
	 * server.
	 */
	if (*uaddr == NULL) {
		if ((srv != NULL) && (thost != NULL)) {
			msg("both timehost and srv pointer used!");
			return (0);
		}
		if (! srv) {
			srv = get_server(netid, thost, &tsrv, teps, 32);
			if (srv == NULL) {
				msg("unable to contruct server data.");
				return (0);
			}
			needfree = 1;	/* need to free data in endpoints */
		}

		ep = srv->ep.ep_val;
		epl = srv->ep.ep_len;

		/* Identify the TCP and UDP endpoints */
		for (i = 0;
			(i < epl) && ((udp_ep == -1) || (tcp_ep == -1)); i++) {
			if (strcasecmp(ep[i].proto, "udp") == 0)
				udp_ep = i;
			if (strcasecmp(ep[i].proto, "tcp") == 0)
				tcp_ep = i;
		}

		/* Check to see if it is UDP or TCP */
		if (tcp_ep > -1) {
			useep = &ep[tcp_ep];
			useua = ep[tcp_ep].uaddr;
			type = SOCK_STREAM;
		} else if (udp_ep > -1) {
			useep = &ep[udp_ep];
			useua = ep[udp_ep].uaddr;
			type = SOCK_DGRAM;
		}

		if (useep == NULL) {
			msg("no acceptable transport endpoints.");
			if (needfree)
				free_eps(teps, tsrv.ep.ep_len);
			return (0);
		}
	}

	/*
	 * Create a sockaddr from the uaddr.
	 */
	if (*uaddr != NULL)
		useua = *uaddr;

	/* Fixup test for NIS+ */
	sscanf(useua, "%d.%d.%d.%d.", &a1, &a2, &a3, &a4);
	sprintf(ipuaddr, "%d.%d.%d.%d.0.111", a1, a2, a3, a4);
	useua = &ipuaddr[0];

	bzero((char *)&sin, sizeof(sin));
	if (uaddr_to_sockaddr(useua, &sin)) {
		msg("unable to translate uaddr to sockaddr.");
		if (needfree)
			free_eps(teps, tsrv.ep.ep_len);
		return (0);
	}

	/*
	 * Create the client handle to rpcbind. Note we always try
	 * version 3 since that is the earliest version that supports
	 * the RPCB_GETTIME call. Also it is the version that comes
	 * standard with SVR4. Since most everyone supports TCP/IP
	 * we could consider trying the rtime call first.
	 */
	clnt = clnttcp_create(&sin, RPCBPROG, RPCBVERS, &s, 0, 0);
	if (clnt == NULL) {
		msg("unable to create client handle to rpcbind.");
		if (needfree)
			free_eps(teps, tsrv.ep.ep_len);
		return (0);
	}

	tv.tv_sec = 5;
	tv.tv_usec = 0;
	time_valid = 0;
	status = clnt_call(clnt, RPCBPROC_GETTIME, (xdrproc_t)xdr_void, NULL,
					(xdrproc_t)xdr_u_long, &thetime, tv);
	/*
	 * The only error we check for is anything but success. In
	 * fact we could have seen PROGMISMATCH if talking to a 4.1
	 * machine (pmap v2) or TIMEDOUT if the net was busy.
	 */
	if (status == RPC_SUCCESS)
		time_valid = 1;
	else {
		int save;

		/* Blow away possible stale CLNT handle. */
		if (clnt != NULL) {
			clnt_destroy(clnt);
			clnt = NULL;
		}

		/*
		 * Convert PMAP address into timeservice address
		 * We take advantage of the fact that we "know" what
		 * the universal address looks like for inet transports.
		 *
		 * We also know that the internet timeservice is always
		 * listening on port 37.
		 */
		sscanf(useua, "%d.%d.%d.%d.", &a1, &a2, &a3, &a4);
		sprintf(ut, "%d.%d.%d.%d.0.37", a1, a2, a3, a4);

		if (uaddr_to_sockaddr(ut, &sin)) {
			msg("cannot convert timeservice uaddr to sockaddr.");
			goto error;
		}

		s = socket(AF_INET, type, 0);
		if (s == -1) {
			msg("unable to open fd to network.");
			goto error;
		}

		/*
		 * Now depending on whether or not we're talking to
		 * UDP we set a timeout or not.
		 */
		if (type == SOCK_DGRAM) {
			struct timeval timeout = { 20, 0 };
			struct sockaddr_in from;
			fd_set readfds;
			int res;

			if (sendto(s, &thetime, sizeof(thetime), 0,
				(struct sockaddr *)&sin, sizeof(sin)) == -1) {
				msg("udp : sendto failed.");
				goto error;
			}
			do {
				FD_ZERO(&readfds);
				FD_SET(s, &readfds);
				res = select(_rpc_dtablesize(), &readfds,
				     (fd_set *)NULL, (fd_set *)NULL, &timeout);
			} while (res < 0 && errno == EINTR);
			if (res <= 0)
				goto error;
			len = sizeof(from);
			res = recvfrom(s, (char *)&thetime, sizeof(thetime), 0,
				       (struct sockaddr *)&from, &len);
			if (res == -1) {
				msg("recvfrom failed on udp transport.");
				goto error;
			}
			time_valid = 1;
		} else {
			int res;

			oldsig = (void (*)())signal(SIGALRM, alarm_hndler);
			saw_alarm = 0; /* global tracking the alarm */
			alarm(20); /* only wait 20 seconds */
			res = connect(s, (struct sockaddr *)&sin, sizeof(sin));
			if (res == -1) {
				msg("failed to connect to tcp endpoint.");
				goto error;
			}
			if (saw_alarm) {
				msg("alarm caught it, must be unreachable.");
				goto error;
			}
			res = read(s, (char *)&thetime, sizeof(thetime));
			if (res != sizeof(thetime)) {
				if (saw_alarm)
					msg("timed out TCP call.");
				else
					msg("wrong size of results returned");

				goto error;
			}
			time_valid = 1;
		}
		save = errno;
		(void)close(s);
		errno = save;
		s = RPC_ANYSOCK;

		if (time_valid) {
			thetime = ntohl(thetime);
			thetime = thetime - TOFFSET; /* adjust to UNIX time */
		} else
			thetime = 0;
	}

	gettimeofday(&tv, 0);

error:
	/*
	 * clean up our allocated data structures.
	 */

	if (s != RPC_ANYSOCK)
		(void)close(s);

	if (clnt != NULL)
		clnt_destroy(clnt);

	alarm(0);	/* reset that alarm if its outstanding */
	if (oldsig) {
		signal(SIGALRM, oldsig);
	}

	/*
	 * note, don't free uaddr strings until after we've made a
	 * copy of them.
	 */
	if (time_valid) {
		if (*uaddr == NULL)
			*uaddr = strdup(useua);

		/* Round to the nearest second */
		tv.tv_sec += (tv.tv_sec > 500000) ? 1 : 0;
		delta = (thetime > tv.tv_sec) ? thetime - tv.tv_sec :
						tv.tv_sec - thetime;
		td->tv_sec = (thetime < tv.tv_sec) ? - delta : delta;
		td->tv_usec = 0;
	} else {
		msg("unable to get the server's time.");
	}

	if (needfree)
		free_eps(teps, tsrv.ep.ep_len);

	return (time_valid);
}