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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/lockd/mon.c
4 *
5 * The kernel statd client.
6 *
7 * Copyright (C) 1996, Olaf Kirch <[email protected]>
8 */
9
10#include <linux/types.h>
11#include <linux/kernel.h>
12#include <linux/ktime.h>
13#include <linux/slab.h>
14
15#include <linux/sunrpc/clnt.h>
16#include <linux/sunrpc/addr.h>
17#include <linux/sunrpc/xprtsock.h>
18#include <linux/sunrpc/svc.h>
19
20#include <linux/unaligned.h>
21
22#include "lockd.h"
23#include "netns.h"
24
25#define NLMDBG_FACILITY NLMDBG_MONITOR
26#define NSM_PROGRAM 100024
27#define NSM_VERSION 1
28
29enum {
30 NSMPROC_NULL,
31 NSMPROC_STAT,
32 NSMPROC_MON,
33 NSMPROC_UNMON,
34 NSMPROC_UNMON_ALL,
35 NSMPROC_SIMU_CRASH,
36 NSMPROC_NOTIFY,
37};
38
39struct nsm_args {
40 struct nsm_private *priv;
41 u32 prog; /* RPC callback info */
42 u32 vers;
43 u32 proc;
44
45 char *mon_name;
46 const char *nodename;
47};
48
49struct nsm_res {
50 u32 status;
51 u32 state;
52};
53
54static const struct rpc_program nsm_program;
55static DEFINE_SPINLOCK(nsm_lock);
56
57/*
58 * Local NSM state
59 */
60u32 __read_mostly nsm_local_state;
61bool __read_mostly nsm_use_hostnames;
62
63static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm)
64{
65 return (struct sockaddr *)&nsm->sm_addr;
66}
67
68static struct rpc_clnt *nsm_create(struct net *net, const char *nodename)
69{
70 struct sockaddr_in sin = {
71 .sin_family = AF_INET,
72 .sin_addr.s_addr = htonl(INADDR_LOOPBACK),
73 };
74 struct rpc_create_args args = {
75 .net = net,
76 .protocol = XPRT_TRANSPORT_TCP,
77 .address = (struct sockaddr *)&sin,
78 .addrsize = sizeof(sin),
79 .servername = "rpc.statd",
80 .nodename = nodename,
81 .program = &nsm_program,
82 .version = NSM_VERSION,
83 .authflavor = RPC_AUTH_NULL,
84 .flags = RPC_CLNT_CREATE_NOPING,
85 .cred = current_cred(),
86 };
87
88 return rpc_create(&args);
89}
90
91static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res,
92 const struct nlm_host *host)
93{
94 int status;
95 struct rpc_clnt *clnt;
96 struct nsm_args args = {
97 .priv = &nsm->sm_priv,
98 .prog = NLM_PROGRAM,
99 .vers = 3,
100 .proc = NLMPROC_NSM_NOTIFY,
101 .mon_name = nsm->sm_mon_name,
102 .nodename = host->nodename,
103 };
104 struct rpc_message msg = {
105 .rpc_argp = &args,
106 .rpc_resp = res,
107 };
108
109 memset(res, 0, sizeof(*res));
110
111 clnt = nsm_create(host->net, host->nodename);
112 if (IS_ERR(clnt)) {
113 dprintk("lockd: failed to create NSM upcall transport, "
114 "status=%ld, net=%x\n", PTR_ERR(clnt),
115 host->net->ns.inum);
116 return PTR_ERR(clnt);
117 }
118
119 msg.rpc_proc = &clnt->cl_procinfo[proc];
120 status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN);
121 if (status == -ECONNREFUSED) {
122 dprintk("lockd: NSM upcall RPC failed, status=%d, forcing rebind\n",
123 status);
124 rpc_force_rebind(clnt);
125 status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN);
126 }
127 if (status < 0)
128 dprintk("lockd: NSM upcall RPC failed, status=%d\n",
129 status);
130 else
131 status = 0;
132
133 rpc_shutdown_client(clnt);
134 return status;
135}
136
137/**
138 * nsm_monitor - Notify a peer in case we reboot
139 * @host: pointer to nlm_host of peer to notify
140 *
141 * If this peer is not already monitored, this function sends an
142 * upcall to the local rpc.statd to record the name/address of
143 * the peer to notify in case we reboot.
144 *
145 * Returns zero if the peer is monitored by the local rpc.statd;
146 * otherwise a negative errno value is returned.
147 */
148int nsm_monitor(const struct nlm_host *host)
149{
150 struct nsm_handle *nsm = host->h_nsmhandle;
151 struct nsm_res res;
152 int status;
153
154 dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name);
155
156 if (nsm->sm_monitored)
157 return 0;
158
159 /*
160 * Choose whether to record the caller_name or IP address of
161 * this peer in the local rpc.statd's database.
162 */
163 nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf;
164
165 status = nsm_mon_unmon(nsm, NSMPROC_MON, &res, host);
166 if (unlikely(res.status != 0))
167 status = -EIO;
168 if (unlikely(status < 0)) {
169 pr_notice_ratelimited("lockd: cannot monitor %s\n", nsm->sm_name);
170 return status;
171 }
172
173 nsm->sm_monitored = 1;
174 if (unlikely(nsm_local_state != res.state)) {
175 nsm_local_state = res.state;
176 dprintk("lockd: NSM state changed to %d\n", nsm_local_state);
177 }
178 return 0;
179}
180
181/**
182 * nsm_unmonitor - Unregister peer notification
183 * @host: pointer to nlm_host of peer to stop monitoring
184 *
185 * If this peer is monitored, this function sends an upcall to
186 * tell the local rpc.statd not to send this peer a notification
187 * when we reboot.
188 */
189void nsm_unmonitor(const struct nlm_host *host)
190{
191 struct nsm_handle *nsm = host->h_nsmhandle;
192 struct nsm_res res;
193 int status;
194
195 if (refcount_read(&nsm->sm_count) == 1
196 && nsm->sm_monitored && !nsm->sm_sticky) {
197 dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name);
198
199 status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res, host);
200 if (res.status != 0)
201 status = -EIO;
202 if (status < 0)
203 printk(KERN_NOTICE "lockd: cannot unmonitor %s\n",
204 nsm->sm_name);
205 else
206 nsm->sm_monitored = 0;
207 }
208}
209
210static struct nsm_handle *nsm_lookup_hostname(const struct list_head *nsm_handles,
211 const char *hostname, const size_t len)
212{
213 struct nsm_handle *nsm;
214
215 list_for_each_entry(nsm, nsm_handles, sm_link)
216 if (strlen(nsm->sm_name) == len &&
217 memcmp(nsm->sm_name, hostname, len) == 0)
218 return nsm;
219 return NULL;
220}
221
222static struct nsm_handle *nsm_lookup_addr(const struct list_head *nsm_handles,
223 const struct sockaddr *sap)
224{
225 struct nsm_handle *nsm;
226
227 list_for_each_entry(nsm, nsm_handles, sm_link)
228 if (rpc_cmp_addr(nsm_addr(nsm), sap))
229 return nsm;
230 return NULL;
231}
232
233static struct nsm_handle *nsm_lookup_priv(const struct list_head *nsm_handles,
234 const struct nsm_private *priv)
235{
236 struct nsm_handle *nsm;
237
238 list_for_each_entry(nsm, nsm_handles, sm_link)
239 if (memcmp(nsm->sm_priv.data, priv->data,
240 sizeof(priv->data)) == 0)
241 return nsm;
242 return NULL;
243}
244
245/*
246 * Construct a unique cookie to match this nsm_handle to this monitored
247 * host. It is passed to the local rpc.statd via NSMPROC_MON, and
248 * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these
249 * requests.
250 *
251 * The NSM protocol requires that these cookies be unique while the
252 * system is running. We prefer a stronger requirement of making them
253 * unique across reboots. If user space bugs cause a stale cookie to
254 * be sent to the kernel, it could cause the wrong host to lose its
255 * lock state if cookies were not unique across reboots.
256 *
257 * The cookies are exposed only to local user space via loopback. They
258 * do not appear on the physical network. If we want greater security
259 * for some reason, nsm_init_private() could perform a one-way hash to
260 * obscure the contents of the cookie.
261 */
262static void nsm_init_private(struct nsm_handle *nsm)
263{
264 u64 *p = (u64 *)&nsm->sm_priv.data;
265 s64 ns;
266
267 ns = ktime_get_ns();
268 put_unaligned(ns, p);
269 put_unaligned((unsigned long)nsm, p + 1);
270}
271
272static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap,
273 const size_t salen,
274 const char *hostname,
275 const size_t hostname_len)
276{
277 struct nsm_handle *new;
278
279 if (!hostname)
280 return NULL;
281
282 new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL);
283 if (unlikely(new == NULL))
284 return NULL;
285
286 refcount_set(&new->sm_count, 1);
287 new->sm_name = (char *)(new + 1);
288 memcpy(nsm_addr(new), sap, salen);
289 new->sm_addrlen = salen;
290 nsm_init_private(new);
291
292 if (rpc_ntop(nsm_addr(new), new->sm_addrbuf,
293 sizeof(new->sm_addrbuf)) == 0)
294 (void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf),
295 "unsupported address family");
296 memcpy(new->sm_name, hostname, hostname_len);
297 new->sm_name[hostname_len] = '\0';
298
299 return new;
300}
301
302/**
303 * nsm_get_handle - Find or create a cached nsm_handle
304 * @net: network namespace
305 * @sap: pointer to socket address of handle to find
306 * @salen: length of socket address
307 * @hostname: pointer to C string containing hostname to find
308 * @hostname_len: length of C string
309 *
310 * Behavior is modulated by the global nsm_use_hostnames variable.
311 *
312 * Returns a cached nsm_handle after bumping its ref count, or
313 * returns a fresh nsm_handle if a handle that matches @sap and/or
314 * @hostname cannot be found in the handle cache. Returns NULL if
315 * an error occurs.
316 */
317struct nsm_handle *nsm_get_handle(const struct net *net,
318 const struct sockaddr *sap,
319 const size_t salen, const char *hostname,
320 const size_t hostname_len)
321{
322 struct nsm_handle *cached, *new = NULL;
323 struct lockd_net *ln = net_generic(net, lockd_net_id);
324
325 if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
326 if (printk_ratelimit()) {
327 printk(KERN_WARNING "Invalid hostname \"%.*s\" "
328 "in NFS lock request\n",
329 (int)hostname_len, hostname);
330 }
331 return NULL;
332 }
333
334retry:
335 spin_lock(&nsm_lock);
336
337 if (nsm_use_hostnames && hostname != NULL)
338 cached = nsm_lookup_hostname(&ln->nsm_handles,
339 hostname, hostname_len);
340 else
341 cached = nsm_lookup_addr(&ln->nsm_handles, sap);
342
343 if (cached != NULL) {
344 refcount_inc(&cached->sm_count);
345 spin_unlock(&nsm_lock);
346 kfree(new);
347 dprintk("lockd: found nsm_handle for %s (%s), "
348 "cnt %d\n", cached->sm_name,
349 cached->sm_addrbuf,
350 refcount_read(&cached->sm_count));
351 return cached;
352 }
353
354 if (new != NULL) {
355 list_add(&new->sm_link, &ln->nsm_handles);
356 spin_unlock(&nsm_lock);
357 dprintk("lockd: created nsm_handle for %s (%s)\n",
358 new->sm_name, new->sm_addrbuf);
359 return new;
360 }
361
362 spin_unlock(&nsm_lock);
363
364 new = nsm_create_handle(sap, salen, hostname, hostname_len);
365 if (unlikely(new == NULL))
366 return NULL;
367 goto retry;
368}
369
370/**
371 * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle
372 * @net: network namespace
373 * @info: pointer to NLMPROC_SM_NOTIFY arguments
374 *
375 * Returns a matching nsm_handle if found in the nsm cache. The returned
376 * nsm_handle's reference count is bumped. Otherwise returns NULL if some
377 * error occurred.
378 */
379struct nsm_handle *nsm_reboot_lookup(const struct net *net,
380 const struct lockd_reboot *info)
381{
382 struct nsm_handle *cached;
383 struct lockd_net *ln = net_generic(net, lockd_net_id);
384
385 spin_lock(&nsm_lock);
386
387 cached = nsm_lookup_priv(&ln->nsm_handles, &info->priv);
388 if (unlikely(cached == NULL)) {
389 spin_unlock(&nsm_lock);
390 dprintk("lockd: never saw rebooted peer '%.*s' before\n",
391 info->len, info->mon);
392 return cached;
393 }
394
395 refcount_inc(&cached->sm_count);
396 spin_unlock(&nsm_lock);
397
398 dprintk("lockd: host %s (%s) rebooted, cnt %d\n",
399 cached->sm_name, cached->sm_addrbuf,
400 refcount_read(&cached->sm_count));
401 return cached;
402}
403
404/**
405 * nsm_release - Release an NSM handle
406 * @nsm: pointer to handle to be released
407 *
408 */
409void nsm_release(struct nsm_handle *nsm)
410{
411 if (refcount_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
412 list_del(&nsm->sm_link);
413 spin_unlock(&nsm_lock);
414 dprintk("lockd: destroyed nsm_handle for %s (%s)\n",
415 nsm->sm_name, nsm->sm_addrbuf);
416 kfree(nsm);
417 }
418}
419
420/*
421 * XDR functions for NSM.
422 *
423 * See https://www.opengroup.org/ for details on the Network
424 * Status Monitor wire protocol.
425 */
426
427static void encode_nsm_string(struct xdr_stream *xdr, const char *string)
428{
429 const u32 len = strlen(string);
430 __be32 *p;
431
432 p = xdr_reserve_space(xdr, 4 + len);
433 xdr_encode_opaque(p, string, len);
434}
435
436/*
437 * "mon_name" specifies the host to be monitored.
438 */
439static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp)
440{
441 encode_nsm_string(xdr, argp->mon_name);
442}
443
444/*
445 * The "my_id" argument specifies the hostname and RPC procedure
446 * to be called when the status manager receives notification
447 * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name"
448 * has changed.
449 */
450static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp)
451{
452 __be32 *p;
453
454 encode_nsm_string(xdr, argp->nodename);
455 p = xdr_reserve_space(xdr, 4 + 4 + 4);
456 *p++ = cpu_to_be32(argp->prog);
457 *p++ = cpu_to_be32(argp->vers);
458 *p = cpu_to_be32(argp->proc);
459}
460
461/*
462 * The "mon_id" argument specifies the non-private arguments
463 * of an NSMPROC_MON or NSMPROC_UNMON call.
464 */
465static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp)
466{
467 encode_mon_name(xdr, argp);
468 encode_my_id(xdr, argp);
469}
470
471/*
472 * The "priv" argument may contain private information required
473 * by the NSMPROC_MON call. This information will be supplied in the
474 * NLMPROC_SM_NOTIFY call.
475 */
476static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp)
477{
478 __be32 *p;
479
480 p = xdr_reserve_space(xdr, SM_PRIV_SIZE);
481 xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE);
482}
483
484static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr,
485 const void *argp)
486{
487 encode_mon_id(xdr, argp);
488 encode_priv(xdr, argp);
489}
490
491static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr,
492 const void *argp)
493{
494 encode_mon_id(xdr, argp);
495}
496
497static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp,
498 struct xdr_stream *xdr,
499 void *data)
500{
501 struct nsm_res *resp = data;
502 __be32 *p;
503
504 p = xdr_inline_decode(xdr, 4 + 4);
505 if (unlikely(p == NULL))
506 return -EIO;
507 resp->status = be32_to_cpup(p++);
508 resp->state = be32_to_cpup(p);
509
510 dprintk("lockd: %s status %d state %d\n",
511 __func__, resp->status, resp->state);
512 return 0;
513}
514
515static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp,
516 struct xdr_stream *xdr,
517 void *data)
518{
519 struct nsm_res *resp = data;
520 __be32 *p;
521
522 p = xdr_inline_decode(xdr, 4);
523 if (unlikely(p == NULL))
524 return -EIO;
525 resp->state = be32_to_cpup(p);
526
527 dprintk("lockd: %s state %d\n", __func__, resp->state);
528 return 0;
529}
530
531#define SM_my_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN))
532#define SM_my_id_sz (SM_my_name_sz+3)
533#define SM_mon_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN))
534#define SM_mon_id_sz (SM_mon_name_sz+SM_my_id_sz)
535#define SM_priv_sz (XDR_QUADLEN(SM_PRIV_SIZE))
536#define SM_mon_sz (SM_mon_id_sz+SM_priv_sz)
537#define SM_monres_sz 2
538#define SM_unmonres_sz 1
539
540static const struct rpc_procinfo nsm_procedures[] = {
541[NSMPROC_MON] = {
542 .p_proc = NSMPROC_MON,
543 .p_encode = nsm_xdr_enc_mon,
544 .p_decode = nsm_xdr_dec_stat_res,
545 .p_arglen = SM_mon_sz,
546 .p_replen = SM_monres_sz,
547 .p_statidx = NSMPROC_MON,
548 .p_name = "MONITOR",
549 },
550[NSMPROC_UNMON] = {
551 .p_proc = NSMPROC_UNMON,
552 .p_encode = nsm_xdr_enc_unmon,
553 .p_decode = nsm_xdr_dec_stat,
554 .p_arglen = SM_mon_id_sz,
555 .p_replen = SM_unmonres_sz,
556 .p_statidx = NSMPROC_UNMON,
557 .p_name = "UNMONITOR",
558 },
559};
560
561static unsigned int nsm_version1_counts[ARRAY_SIZE(nsm_procedures)];
562static const struct rpc_version nsm_version1 = {
563 .number = 1,
564 .nrprocs = ARRAY_SIZE(nsm_procedures),
565 .procs = nsm_procedures,
566 .counts = nsm_version1_counts,
567};
568
569static const struct rpc_version *nsm_version[] = {
570 [1] = &nsm_version1,
571};
572
573static struct rpc_stat nsm_stats;
574
575static const struct rpc_program nsm_program = {
576 .name = "statd",
577 .number = NSM_PROGRAM,
578 .nrvers = ARRAY_SIZE(nsm_version),
579 .version = nsm_version,
580 .stats = &nsm_stats
581};