1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. Berkeley Software Design Inc's name may not be used to endorse or
15 *    promote products derived from this software without specific prior
16 *    written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 *      from BSDI kern.c,v 1.2 1998/11/25 22:38:27 don Exp
31 */
32
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: stable/11/usr.sbin/rpc.lockd/kern.c 330449 2018-03-05 07:26:05Z eadler $");
35
36#include <sys/param.h>
37#include <sys/mount.h>
38#include <sys/queue.h>
39#include <sys/socket.h>
40#include <sys/stat.h>
41
42#include <netinet/in.h>
43#include <arpa/inet.h>
44
45#include <err.h>
46#include <errno.h>
47#include <fcntl.h>
48#include <paths.h>
49#include <pwd.h>
50#include <stdio.h>
51#include <stdlib.h>
52#include <string.h>
53#include <syslog.h>
54#include <unistd.h>
55#include <netdb.h>
56
57#include "nlm_prot.h"
58#include <nfs/nfsproto.h>
59#include <nfs/nfs_lock.h>
60
61#include "lockd.h"
62#include "lockd_lock.h"
63#include <nfsclient/nfs.h>
64
65#define DAEMON_USERNAME	"daemon"
66
67/* Lock request owner. */
68typedef struct __owner {
69	pid_t	 pid;				/* Process ID. */
70	time_t	 tod;				/* Time-of-day. */
71} OWNER;
72static OWNER owner;
73
74static char hostname[MAXHOSTNAMELEN + 1];	/* Hostname. */
75static int devfd;
76
77static void	client_cleanup(void);
78static const char *from_addr(struct sockaddr *);
79int	lock_request(LOCKD_MSG *);
80static void	set_auth(CLIENT *cl, struct xucred *ucred);
81void	show(LOCKD_MSG *);
82int	test_request(LOCKD_MSG *);
83int	unlock_request(LOCKD_MSG *);
84
85static int
86nfslockdans(int vers, struct lockd_ans *ansp)
87{
88
89	ansp->la_vers = vers;
90	return (write(devfd, ansp, sizeof *ansp) <= 0);
91}
92
93/*
94 * will break because fifo needs to be repopened when EOF'd
95 */
96#define lockd_seteuid(uid)	seteuid(uid)
97
98#define d_calls (debug_level > 1)
99#define d_args (debug_level > 2)
100
101static const char *
102from_addr(struct sockaddr *saddr)
103{
104	static char inet_buf[INET6_ADDRSTRLEN];
105
106	if (getnameinfo(saddr, saddr->sa_len, inet_buf, sizeof(inet_buf),
107			NULL, 0, NI_NUMERICHOST) == 0)
108		return inet_buf;
109	return "???";
110}
111
112void
113client_cleanup(void)
114{
115	(void)lockd_seteuid(0);
116	exit(-1);
117}
118
119/*
120 * client_request --
121 *	Loop around messages from the kernel, forwarding them off to
122 *	NLM servers.
123 */
124pid_t
125client_request(void)
126{
127	LOCKD_MSG msg;
128	int nr, ret;
129	pid_t child;
130	uid_t daemon_uid;
131	struct passwd *pw;
132
133	/* Open the dev . */
134	devfd = open(_PATH_DEV _PATH_NFSLCKDEV, O_RDWR | O_NONBLOCK);
135	if (devfd < 0) {
136		syslog(LOG_ERR, "open: %s: %m", _PATH_NFSLCKDEV);
137		goto err;
138	}
139
140	signal(SIGPIPE, SIG_IGN);
141
142	/*
143	 * Create a separate process, the client code is really a separate
144	 * daemon that shares a lot of code.
145	 */
146	switch (child = fork()) {
147	case -1:
148		err(1, "fork");
149	case 0:
150		setproctitle("client");
151		break;
152	default:
153		setproctitle("server");
154		return (child);
155	}
156
157	signal(SIGHUP, (sig_t)client_cleanup);
158	signal(SIGTERM, (sig_t)client_cleanup);
159
160	/* Setup. */
161	(void)time(&owner.tod);
162	owner.pid = getpid();
163	(void)gethostname(hostname, sizeof(hostname) - 1);
164
165	pw = getpwnam(DAEMON_USERNAME);
166	if (pw == NULL) {
167		syslog(LOG_ERR, "getpwnam: %s: %m", DAEMON_USERNAME);
168		goto err;
169	}
170	daemon_uid = pw->pw_uid;
171	/* drop our root privileges */
172	(void)lockd_seteuid(daemon_uid);
173
174	for (;;) {
175		/* Read the fixed length message. */
176		if ((nr = read(devfd, &msg, sizeof(msg))) == sizeof(msg)) {
177			if (d_args)
178				show(&msg);
179
180			if (msg.lm_version != LOCKD_MSG_VERSION) {
181				syslog(LOG_ERR,
182				    "unknown msg type: %d", msg.lm_version);
183			}
184			/*
185			 * Send it to the NLM server and don't grant the lock
186			 * if we fail for any reason.
187			 */
188			switch (msg.lm_fl.l_type) {
189			case F_RDLCK:
190			case F_WRLCK:
191				if (msg.lm_getlk)
192					ret = test_request(&msg);
193				else
194					ret = lock_request(&msg);
195				break;
196			case F_UNLCK:
197				ret = unlock_request(&msg);
198				break;
199			default:
200				ret = 1;
201				syslog(LOG_ERR,
202				    "unknown lock type: %d", msg.lm_fl.l_type);
203				break;
204			}
205			if (ret) {
206				struct lockd_ans ans;
207
208				ans.la_msg_ident = msg.lm_msg_ident;
209				ans.la_errno = EHOSTUNREACH;
210
211				if (nfslockdans(LOCKD_ANS_VERSION, &ans)) {
212					syslog((errno == EPIPE ? LOG_INFO :
213						LOG_ERR), "process %lu: %m",
214						(u_long)msg.lm_msg_ident.pid);
215				}
216			}
217		} else if (nr == -1) {
218			if (errno != EAGAIN) {
219				syslog(LOG_ERR, "read: %s: %m", _PATH_NFSLCKDEV);
220				goto err;
221			}
222		} else if (nr != 0) {
223			syslog(LOG_ERR,
224			    "%s: discard %d bytes", _PATH_NFSLCKDEV, nr);
225		}
226	}
227
228	/* Reached only on error. */
229err:
230	(void)lockd_seteuid(0);
231	_exit (1);
232}
233
234void
235set_auth(CLIENT *cl, struct xucred *xucred)
236{
237	int ngroups;
238
239	ngroups = xucred->cr_ngroups - 1;
240	if (ngroups > NGRPS)
241		ngroups = NGRPS;
242        if (cl->cl_auth != NULL)
243                cl->cl_auth->ah_ops->ah_destroy(cl->cl_auth);
244        cl->cl_auth = authunix_create(hostname,
245                        xucred->cr_uid,
246                        xucred->cr_groups[0],
247                        ngroups,
248                        &xucred->cr_groups[1]);
249}
250
251
252/*
253 * test_request --
254 *	Convert a lock LOCKD_MSG into an NLM request, and send it off.
255 */
256int
257test_request(LOCKD_MSG *msg)
258{
259	CLIENT *cli;
260	struct timeval timeout = {0, 0};	/* No timeout, no response. */
261	char dummy;
262
263	if (d_calls)
264		syslog(LOG_DEBUG, "test request: %s: %s to %s",
265		    msg->lm_nfsv3 ? "V4" : "V1/3",
266		    msg->lm_fl.l_type == F_WRLCK ? "write" : "read",
267		    from_addr((struct sockaddr *)&msg->lm_addr));
268
269	if (msg->lm_nfsv3) {
270		struct nlm4_testargs arg4;
271
272		arg4.cookie.n_bytes = (char *)&msg->lm_msg_ident;
273		arg4.cookie.n_len = sizeof(msg->lm_msg_ident);
274		arg4.exclusive = msg->lm_fl.l_type == F_WRLCK ? 1 : 0;
275		arg4.alock.caller_name = hostname;
276		arg4.alock.fh.n_bytes = (char *)&msg->lm_fh;
277		arg4.alock.fh.n_len = msg->lm_fh_len;
278		arg4.alock.oh.n_bytes = (char *)&owner;
279		arg4.alock.oh.n_len = sizeof(owner);
280		arg4.alock.svid = msg->lm_msg_ident.pid;
281		arg4.alock.l_offset = msg->lm_fl.l_start;
282		arg4.alock.l_len = msg->lm_fl.l_len;
283
284		if ((cli = get_client(
285		    (struct sockaddr *)&msg->lm_addr,
286		    NLM_VERS4)) == NULL)
287			return (1);
288
289		set_auth(cli, &msg->lm_cred);
290		(void)clnt_call(cli, NLM_TEST_MSG,
291		    (xdrproc_t)xdr_nlm4_testargs, &arg4,
292		    (xdrproc_t)xdr_void, &dummy, timeout);
293	} else {
294		struct nlm_testargs arg;
295
296		arg.cookie.n_bytes = (char *)&msg->lm_msg_ident;
297		arg.cookie.n_len = sizeof(msg->lm_msg_ident);
298		arg.exclusive = msg->lm_fl.l_type == F_WRLCK ? 1 : 0;
299		arg.alock.caller_name = hostname;
300		arg.alock.fh.n_bytes = (char *)&msg->lm_fh;
301		arg.alock.fh.n_len = msg->lm_fh_len;
302		arg.alock.oh.n_bytes = (char *)&owner;
303		arg.alock.oh.n_len = sizeof(owner);
304		arg.alock.svid = msg->lm_msg_ident.pid;
305		arg.alock.l_offset = msg->lm_fl.l_start;
306		arg.alock.l_len = msg->lm_fl.l_len;
307
308		if ((cli = get_client(
309		    (struct sockaddr *)&msg->lm_addr,
310		    NLM_VERS)) == NULL)
311			return (1);
312
313		set_auth(cli, &msg->lm_cred);
314		(void)clnt_call(cli, NLM_TEST_MSG,
315		    (xdrproc_t)xdr_nlm_testargs, &arg,
316		    (xdrproc_t)xdr_void, &dummy, timeout);
317	}
318	return (0);
319}
320
321/*
322 * lock_request --
323 *	Convert a lock LOCKD_MSG into an NLM request, and send it off.
324 */
325int
326lock_request(LOCKD_MSG *msg)
327{
328	CLIENT *cli;
329	struct nlm4_lockargs arg4;
330	struct nlm_lockargs arg;
331	struct timeval timeout = {0, 0};	/* No timeout, no response. */
332	char dummy;
333
334	if (d_calls)
335		syslog(LOG_DEBUG, "lock request: %s: %s to %s",
336		    msg->lm_nfsv3 ? "V4" : "V1/3",
337		    msg->lm_fl.l_type == F_WRLCK ? "write" : "read",
338		    from_addr((struct sockaddr *)&msg->lm_addr));
339
340	if (msg->lm_nfsv3) {
341		arg4.cookie.n_bytes = (char *)&msg->lm_msg_ident;
342		arg4.cookie.n_len = sizeof(msg->lm_msg_ident);
343		arg4.block = msg->lm_wait ? 1 : 0;
344		arg4.exclusive = msg->lm_fl.l_type == F_WRLCK ? 1 : 0;
345		arg4.alock.caller_name = hostname;
346		arg4.alock.fh.n_bytes = (char *)&msg->lm_fh;
347		arg4.alock.fh.n_len = msg->lm_fh_len;
348		arg4.alock.oh.n_bytes = (char *)&owner;
349		arg4.alock.oh.n_len = sizeof(owner);
350		arg4.alock.svid = msg->lm_msg_ident.pid;
351		arg4.alock.l_offset = msg->lm_fl.l_start;
352		arg4.alock.l_len = msg->lm_fl.l_len;
353		arg4.reclaim = 0;
354		arg4.state = nsm_state;
355
356		if ((cli = get_client(
357		    (struct sockaddr *)&msg->lm_addr,
358		    NLM_VERS4)) == NULL)
359			return (1);
360
361		set_auth(cli, &msg->lm_cred);
362		(void)clnt_call(cli, NLM_LOCK_MSG,
363		    (xdrproc_t)xdr_nlm4_lockargs, &arg4,
364		    (xdrproc_t)xdr_void, &dummy, timeout);
365	} else {
366		arg.cookie.n_bytes = (char *)&msg->lm_msg_ident;
367		arg.cookie.n_len = sizeof(msg->lm_msg_ident);
368		arg.block = msg->lm_wait ? 1 : 0;
369		arg.exclusive = msg->lm_fl.l_type == F_WRLCK ? 1 : 0;
370		arg.alock.caller_name = hostname;
371		arg.alock.fh.n_bytes = (char *)&msg->lm_fh;
372		arg.alock.fh.n_len = msg->lm_fh_len;
373		arg.alock.oh.n_bytes = (char *)&owner;
374		arg.alock.oh.n_len = sizeof(owner);
375		arg.alock.svid = msg->lm_msg_ident.pid;
376		arg.alock.l_offset = msg->lm_fl.l_start;
377		arg.alock.l_len = msg->lm_fl.l_len;
378		arg.reclaim = 0;
379		arg.state = nsm_state;
380
381		if ((cli = get_client(
382		    (struct sockaddr *)&msg->lm_addr,
383		    NLM_VERS)) == NULL)
384			return (1);
385
386		set_auth(cli, &msg->lm_cred);
387		(void)clnt_call(cli, NLM_LOCK_MSG,
388		    (xdrproc_t)xdr_nlm_lockargs, &arg,
389		    (xdrproc_t)xdr_void, &dummy, timeout);
390	}
391	return (0);
392}
393
394/*
395 * unlock_request --
396 *	Convert an unlock LOCKD_MSG into an NLM request, and send it off.
397 */
398int
399unlock_request(LOCKD_MSG *msg)
400{
401	CLIENT *cli;
402	struct nlm4_unlockargs arg4;
403	struct nlm_unlockargs arg;
404	struct timeval timeout = {0, 0};	/* No timeout, no response. */
405	char dummy;
406
407	if (d_calls)
408		syslog(LOG_DEBUG, "unlock request: %s: to %s",
409		    msg->lm_nfsv3 ? "V4" : "V1/3",
410		    from_addr((struct sockaddr *)&msg->lm_addr));
411
412	if (msg->lm_nfsv3) {
413		arg4.cookie.n_bytes = (char *)&msg->lm_msg_ident;
414		arg4.cookie.n_len = sizeof(msg->lm_msg_ident);
415		arg4.alock.caller_name = hostname;
416		arg4.alock.fh.n_bytes = (char *)&msg->lm_fh;
417		arg4.alock.fh.n_len = msg->lm_fh_len;
418		arg4.alock.oh.n_bytes = (char *)&owner;
419		arg4.alock.oh.n_len = sizeof(owner);
420		arg4.alock.svid = msg->lm_msg_ident.pid;
421		arg4.alock.l_offset = msg->lm_fl.l_start;
422		arg4.alock.l_len = msg->lm_fl.l_len;
423
424		if ((cli = get_client(
425		    (struct sockaddr *)&msg->lm_addr,
426		    NLM_VERS4)) == NULL)
427			return (1);
428
429		set_auth(cli, &msg->lm_cred);
430		(void)clnt_call(cli, NLM_UNLOCK_MSG,
431		    (xdrproc_t)xdr_nlm4_unlockargs, &arg4,
432		    (xdrproc_t)xdr_void, &dummy, timeout);
433	} else {
434		arg.cookie.n_bytes = (char *)&msg->lm_msg_ident;
435		arg.cookie.n_len = sizeof(msg->lm_msg_ident);
436		arg.alock.caller_name = hostname;
437		arg.alock.fh.n_bytes = (char *)&msg->lm_fh;
438		arg.alock.fh.n_len = msg->lm_fh_len;
439		arg.alock.oh.n_bytes = (char *)&owner;
440		arg.alock.oh.n_len = sizeof(owner);
441		arg.alock.svid = msg->lm_msg_ident.pid;
442		arg.alock.l_offset = msg->lm_fl.l_start;
443		arg.alock.l_len = msg->lm_fl.l_len;
444
445		if ((cli = get_client(
446		    (struct sockaddr *)&msg->lm_addr,
447		    NLM_VERS)) == NULL)
448			return (1);
449
450		set_auth(cli, &msg->lm_cred);
451		(void)clnt_call(cli, NLM_UNLOCK_MSG,
452		    (xdrproc_t)xdr_nlm_unlockargs, &arg,
453		    (xdrproc_t)xdr_void, &dummy, timeout);
454	}
455
456	return (0);
457}
458
459int
460lock_answer(int pid, netobj *netcookie, int result, int *pid_p, int version)
461{
462	struct lockd_ans ans;
463
464	if (netcookie->n_len != sizeof(ans.la_msg_ident)) {
465		if (pid == -1) {	/* we're screwed */
466			syslog(LOG_ERR, "inedible nlm cookie");
467			return -1;
468		}
469		ans.la_msg_ident.pid = pid;
470		ans.la_msg_ident.msg_seq = -1;
471	} else {
472		memcpy(&ans.la_msg_ident, netcookie->n_bytes,
473		    sizeof(ans.la_msg_ident));
474	}
475
476	if (d_calls)
477		syslog(LOG_DEBUG, "lock answer: pid %lu: %s %d",
478		    (unsigned long)ans.la_msg_ident.pid,
479		    version == NLM_VERS4 ? "nlmv4" : "nlmv3",
480		    result);
481
482	ans.la_set_getlk_pid = 0;
483	if (version == NLM_VERS4)
484		switch (result) {
485		case nlm4_granted:
486			ans.la_errno = 0;
487			break;
488		default:
489			ans.la_errno = EACCES;
490			break;
491		case nlm4_denied:
492			if (pid_p == NULL)
493				ans.la_errno = EAGAIN;
494			else {
495				/* this is an answer to a nlm_test msg */
496				ans.la_set_getlk_pid = 1;
497				ans.la_getlk_pid = *pid_p;
498				ans.la_errno = 0;
499			}
500			break;
501		case nlm4_denied_nolocks:
502			ans.la_errno = EAGAIN;
503			break;
504		case nlm4_blocked:
505			return -1;
506			/* NOTREACHED */
507		case nlm4_denied_grace_period:
508			ans.la_errno = EAGAIN;
509			break;
510		case nlm4_deadlck:
511			ans.la_errno = EDEADLK;
512			break;
513		case nlm4_rofs:
514			ans.la_errno = EROFS;
515			break;
516		case nlm4_stale_fh:
517			ans.la_errno = ESTALE;
518			break;
519		case nlm4_fbig:
520			ans.la_errno = EFBIG;
521			break;
522		case nlm4_failed:
523			ans.la_errno = EACCES;
524			break;
525		}
526	else
527		switch (result) {
528		case nlm_granted:
529			ans.la_errno = 0;
530			break;
531		default:
532			ans.la_errno = EACCES;
533			break;
534		case nlm_denied:
535			if (pid_p == NULL)
536				ans.la_errno = EAGAIN;
537			else {
538				/* this is an answer to a nlm_test msg */
539				ans.la_set_getlk_pid = 1;
540				ans.la_getlk_pid = *pid_p;
541				ans.la_errno = 0;
542			}
543			break;
544		case nlm_denied_nolocks:
545			ans.la_errno = EAGAIN;
546			break;
547		case nlm_blocked:
548			return -1;
549			/* NOTREACHED */
550		case nlm_denied_grace_period:
551			ans.la_errno = EAGAIN;
552			break;
553		case nlm_deadlck:
554			ans.la_errno = EDEADLK;
555			break;
556		}
557
558	if (nfslockdans(LOCKD_ANS_VERSION, &ans)) {
559		syslog(((errno == EPIPE || errno == ESRCH) ?
560			LOG_INFO : LOG_ERR),
561			"process %lu: %m", (u_long)ans.la_msg_ident.pid);
562		return -1;
563	}
564	return 0;
565}
566
567/*
568 * show --
569 *	Display the contents of a kernel LOCKD_MSG structure.
570 */
571void
572show(LOCKD_MSG *mp)
573{
574	static char hex[] = "0123456789abcdef";
575	struct fid *fidp;
576	fsid_t *fsidp;
577	size_t len;
578	u_int8_t *p, *t, buf[NFS_SMALLFH*3+1];
579
580	syslog(LOG_DEBUG, "process ID: %lu\n", (long)mp->lm_msg_ident.pid);
581
582	fsidp = (fsid_t *)&mp->lm_fh;
583	fidp = (struct fid *)((u_int8_t *)&mp->lm_fh + sizeof(fsid_t));
584
585	for (t = buf, p = (u_int8_t *)mp->lm_fh,
586	    len = mp->lm_fh_len;
587	    len > 0; ++p, --len) {
588		*t++ = '\\';
589		*t++ = hex[(*p & 0xf0) >> 4];
590		*t++ = hex[*p & 0x0f];
591	}
592	*t = '\0';
593
594	syslog(LOG_DEBUG, "fh_len %d, fh %s\n", (int)mp->lm_fh_len, buf);
595
596	/* Show flock structure. */
597	syslog(LOG_DEBUG, "start %llu; len %llu; pid %lu; type %d; whence %d\n",
598	    (unsigned long long)mp->lm_fl.l_start,
599	    (unsigned long long)mp->lm_fl.l_len, (u_long)mp->lm_fl.l_pid,
600	    mp->lm_fl.l_type, mp->lm_fl.l_whence);
601
602	/* Show wait flag. */
603	syslog(LOG_DEBUG, "wait was %s\n", mp->lm_wait ? "set" : "not set");
604}
605