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1 | // SPDX-License-Identifier: GPL-2.0 | |
2 | /* | |
3 | * linux/fs/nfs/callback.c | |
4 | * | |
5 | * Copyright (C) 2004 Trond Myklebust | |
6 | * | |
7 | * NFSv4 callback handling | |
8 | */ | |
9 | ||
10 | #include <linux/completion.h> | |
11 | #include <linux/ip.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/sched/signal.h> | |
14 | #include <linux/sunrpc/svc.h> | |
15 | #include <linux/sunrpc/svcsock.h> | |
16 | #include <linux/nfs_fs.h> | |
17 | #include <linux/errno.h> | |
18 | #include <linux/mutex.h> | |
19 | #include <linux/freezer.h> | |
20 | #include <linux/kthread.h> | |
21 | #include <linux/sunrpc/svcauth_gss.h> | |
22 | #include <linux/sunrpc/bc_xprt.h> | |
23 | ||
24 | #include <net/inet_sock.h> | |
25 | ||
26 | #include "nfs4_fs.h" | |
27 | #include "callback.h" | |
28 | #include "internal.h" | |
29 | #include "netns.h" | |
30 | ||
31 | #define NFSDBG_FACILITY NFSDBG_CALLBACK | |
32 | ||
33 | struct nfs_callback_data { | |
34 | unsigned int users; | |
35 | struct svc_serv *serv; | |
36 | }; | |
37 | ||
38 | static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1]; | |
39 | static DEFINE_MUTEX(nfs_callback_mutex); | |
40 | static struct svc_program nfs4_callback_program; | |
41 | ||
42 | static int nfs4_callback_up_net(struct svc_serv *serv, struct net *net) | |
43 | { | |
44 | const struct cred *cred = current_cred(); | |
45 | int ret; | |
46 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
47 | ||
48 | ret = svc_create_xprt(serv, "tcp", net, PF_INET, | |
49 | nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS, | |
50 | cred); | |
51 | if (ret <= 0) | |
52 | goto out_err; | |
53 | nn->nfs_callback_tcpport = ret; | |
54 | dprintk("NFS: Callback listener port = %u (af %u, net %x)\n", | |
55 | nn->nfs_callback_tcpport, PF_INET, net->ns.inum); | |
56 | ||
57 | ret = svc_create_xprt(serv, "tcp", net, PF_INET6, | |
58 | nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS, | |
59 | cred); | |
60 | if (ret > 0) { | |
61 | nn->nfs_callback_tcpport6 = ret; | |
62 | dprintk("NFS: Callback listener port = %u (af %u, net %x)\n", | |
63 | nn->nfs_callback_tcpport6, PF_INET6, net->ns.inum); | |
64 | } else if (ret != -EAFNOSUPPORT) | |
65 | goto out_err; | |
66 | return 0; | |
67 | ||
68 | out_err: | |
69 | return (ret) ? ret : -ENOMEM; | |
70 | } | |
71 | ||
72 | /* | |
73 | * This is the NFSv4 callback kernel thread. | |
74 | */ | |
75 | static int | |
76 | nfs4_callback_svc(void *vrqstp) | |
77 | { | |
78 | int err; | |
79 | struct svc_rqst *rqstp = vrqstp; | |
80 | ||
81 | set_freezable(); | |
82 | ||
83 | while (!kthread_freezable_should_stop(NULL)) { | |
84 | ||
85 | if (signal_pending(current)) | |
86 | flush_signals(current); | |
87 | /* | |
88 | * Listen for a request on the socket | |
89 | */ | |
90 | err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT); | |
91 | if (err == -EAGAIN || err == -EINTR) | |
92 | continue; | |
93 | svc_process(rqstp); | |
94 | } | |
95 | svc_exit_thread(rqstp); | |
96 | module_put_and_exit(0); | |
97 | return 0; | |
98 | } | |
99 | ||
100 | #if defined(CONFIG_NFS_V4_1) | |
101 | /* | |
102 | * The callback service for NFSv4.1 callbacks | |
103 | */ | |
104 | static int | |
105 | nfs41_callback_svc(void *vrqstp) | |
106 | { | |
107 | struct svc_rqst *rqstp = vrqstp; | |
108 | struct svc_serv *serv = rqstp->rq_server; | |
109 | struct rpc_rqst *req; | |
110 | int error; | |
111 | DEFINE_WAIT(wq); | |
112 | ||
113 | set_freezable(); | |
114 | ||
115 | while (!kthread_freezable_should_stop(NULL)) { | |
116 | ||
117 | if (signal_pending(current)) | |
118 | flush_signals(current); | |
119 | ||
120 | prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE); | |
121 | spin_lock_bh(&serv->sv_cb_lock); | |
122 | if (!list_empty(&serv->sv_cb_list)) { | |
123 | req = list_first_entry(&serv->sv_cb_list, | |
124 | struct rpc_rqst, rq_bc_list); | |
125 | list_del(&req->rq_bc_list); | |
126 | spin_unlock_bh(&serv->sv_cb_lock); | |
127 | finish_wait(&serv->sv_cb_waitq, &wq); | |
128 | dprintk("Invoking bc_svc_process()\n"); | |
129 | error = bc_svc_process(serv, req, rqstp); | |
130 | dprintk("bc_svc_process() returned w/ error code= %d\n", | |
131 | error); | |
132 | } else { | |
133 | spin_unlock_bh(&serv->sv_cb_lock); | |
134 | if (!kthread_should_stop()) | |
135 | schedule(); | |
136 | finish_wait(&serv->sv_cb_waitq, &wq); | |
137 | } | |
138 | } | |
139 | svc_exit_thread(rqstp); | |
140 | module_put_and_exit(0); | |
141 | return 0; | |
142 | } | |
143 | ||
144 | static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, | |
145 | struct svc_serv *serv) | |
146 | { | |
147 | if (minorversion) | |
148 | /* | |
149 | * Save the svc_serv in the transport so that it can | |
150 | * be referenced when the session backchannel is initialized | |
151 | */ | |
152 | xprt->bc_serv = serv; | |
153 | } | |
154 | #else | |
155 | static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, | |
156 | struct svc_serv *serv) | |
157 | { | |
158 | } | |
159 | #endif /* CONFIG_NFS_V4_1 */ | |
160 | ||
161 | static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt, | |
162 | struct svc_serv *serv) | |
163 | { | |
164 | int nrservs = nfs_callback_nr_threads; | |
165 | int ret; | |
166 | ||
167 | nfs_callback_bc_serv(minorversion, xprt, serv); | |
168 | ||
169 | if (nrservs < NFS4_MIN_NR_CALLBACK_THREADS) | |
170 | nrservs = NFS4_MIN_NR_CALLBACK_THREADS; | |
171 | ||
172 | if (serv->sv_nrthreads-1 == nrservs) | |
173 | return 0; | |
174 | ||
175 | ret = serv->sv_ops->svo_setup(serv, NULL, nrservs); | |
176 | if (ret) { | |
177 | serv->sv_ops->svo_setup(serv, NULL, 0); | |
178 | return ret; | |
179 | } | |
180 | dprintk("nfs_callback_up: service started\n"); | |
181 | return 0; | |
182 | } | |
183 | ||
184 | static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net) | |
185 | { | |
186 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
187 | ||
188 | if (--nn->cb_users[minorversion]) | |
189 | return; | |
190 | ||
191 | dprintk("NFS: destroy per-net callback data; net=%x\n", net->ns.inum); | |
192 | svc_shutdown_net(serv, net); | |
193 | } | |
194 | ||
195 | static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, | |
196 | struct net *net, struct rpc_xprt *xprt) | |
197 | { | |
198 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
199 | int ret; | |
200 | ||
201 | if (nn->cb_users[minorversion]++) | |
202 | return 0; | |
203 | ||
204 | dprintk("NFS: create per-net callback data; net=%x\n", net->ns.inum); | |
205 | ||
206 | ret = svc_bind(serv, net); | |
207 | if (ret < 0) { | |
208 | printk(KERN_WARNING "NFS: bind callback service failed\n"); | |
209 | goto err_bind; | |
210 | } | |
211 | ||
212 | ret = 0; | |
213 | if (!IS_ENABLED(CONFIG_NFS_V4_1) || minorversion == 0) | |
214 | ret = nfs4_callback_up_net(serv, net); | |
215 | else if (xprt->ops->bc_setup) | |
216 | set_bc_enabled(serv); | |
217 | else | |
218 | ret = -EPROTONOSUPPORT; | |
219 | ||
220 | if (ret < 0) { | |
221 | printk(KERN_ERR "NFS: callback service start failed\n"); | |
222 | goto err_socks; | |
223 | } | |
224 | return 0; | |
225 | ||
226 | err_socks: | |
227 | svc_rpcb_cleanup(serv, net); | |
228 | err_bind: | |
229 | nn->cb_users[minorversion]--; | |
230 | dprintk("NFS: Couldn't create callback socket: err = %d; " | |
231 | "net = %x\n", ret, net->ns.inum); | |
232 | return ret; | |
233 | } | |
234 | ||
235 | static const struct svc_serv_ops nfs40_cb_sv_ops = { | |
236 | .svo_function = nfs4_callback_svc, | |
237 | .svo_enqueue_xprt = svc_xprt_do_enqueue, | |
238 | .svo_setup = svc_set_num_threads_sync, | |
239 | .svo_module = THIS_MODULE, | |
240 | }; | |
241 | #if defined(CONFIG_NFS_V4_1) | |
242 | static const struct svc_serv_ops nfs41_cb_sv_ops = { | |
243 | .svo_function = nfs41_callback_svc, | |
244 | .svo_enqueue_xprt = svc_xprt_do_enqueue, | |
245 | .svo_setup = svc_set_num_threads_sync, | |
246 | .svo_module = THIS_MODULE, | |
247 | }; | |
248 | ||
249 | static const struct svc_serv_ops *nfs4_cb_sv_ops[] = { | |
250 | [0] = &nfs40_cb_sv_ops, | |
251 | [1] = &nfs41_cb_sv_ops, | |
252 | }; | |
253 | #else | |
254 | static const struct svc_serv_ops *nfs4_cb_sv_ops[] = { | |
255 | [0] = &nfs40_cb_sv_ops, | |
256 | [1] = NULL, | |
257 | }; | |
258 | #endif | |
259 | ||
260 | static struct svc_serv *nfs_callback_create_svc(int minorversion) | |
261 | { | |
262 | struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; | |
263 | const struct svc_serv_ops *sv_ops; | |
264 | struct svc_serv *serv; | |
265 | ||
266 | /* | |
267 | * Check whether we're already up and running. | |
268 | */ | |
269 | if (cb_info->serv) { | |
270 | /* | |
271 | * Note: increase service usage, because later in case of error | |
272 | * svc_destroy() will be called. | |
273 | */ | |
274 | svc_get(cb_info->serv); | |
275 | return cb_info->serv; | |
276 | } | |
277 | ||
278 | switch (minorversion) { | |
279 | case 0: | |
280 | sv_ops = nfs4_cb_sv_ops[0]; | |
281 | break; | |
282 | default: | |
283 | sv_ops = nfs4_cb_sv_ops[1]; | |
284 | } | |
285 | ||
286 | if (sv_ops == NULL) | |
287 | return ERR_PTR(-ENOTSUPP); | |
288 | ||
289 | /* | |
290 | * Sanity check: if there's no task, | |
291 | * we should be the first user ... | |
292 | */ | |
293 | if (cb_info->users) | |
294 | printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n", | |
295 | cb_info->users); | |
296 | ||
297 | serv = svc_create_pooled(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, sv_ops); | |
298 | if (!serv) { | |
299 | printk(KERN_ERR "nfs_callback_create_svc: create service failed\n"); | |
300 | return ERR_PTR(-ENOMEM); | |
301 | } | |
302 | cb_info->serv = serv; | |
303 | /* As there is only one thread we need to over-ride the | |
304 | * default maximum of 80 connections | |
305 | */ | |
306 | serv->sv_maxconn = 1024; | |
307 | dprintk("nfs_callback_create_svc: service created\n"); | |
308 | return serv; | |
309 | } | |
310 | ||
311 | /* | |
312 | * Bring up the callback thread if it is not already up. | |
313 | */ | |
314 | int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt) | |
315 | { | |
316 | struct svc_serv *serv; | |
317 | struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; | |
318 | int ret; | |
319 | struct net *net = xprt->xprt_net; | |
320 | ||
321 | mutex_lock(&nfs_callback_mutex); | |
322 | ||
323 | serv = nfs_callback_create_svc(minorversion); | |
324 | if (IS_ERR(serv)) { | |
325 | ret = PTR_ERR(serv); | |
326 | goto err_create; | |
327 | } | |
328 | ||
329 | ret = nfs_callback_up_net(minorversion, serv, net, xprt); | |
330 | if (ret < 0) | |
331 | goto err_net; | |
332 | ||
333 | ret = nfs_callback_start_svc(minorversion, xprt, serv); | |
334 | if (ret < 0) | |
335 | goto err_start; | |
336 | ||
337 | cb_info->users++; | |
338 | /* | |
339 | * svc_create creates the svc_serv with sv_nrthreads == 1, and then | |
340 | * svc_prepare_thread increments that. So we need to call svc_destroy | |
341 | * on both success and failure so that the refcount is 1 when the | |
342 | * thread exits. | |
343 | */ | |
344 | err_net: | |
345 | if (!cb_info->users) | |
346 | cb_info->serv = NULL; | |
347 | svc_destroy(serv); | |
348 | err_create: | |
349 | mutex_unlock(&nfs_callback_mutex); | |
350 | return ret; | |
351 | ||
352 | err_start: | |
353 | nfs_callback_down_net(minorversion, serv, net); | |
354 | dprintk("NFS: Couldn't create server thread; err = %d\n", ret); | |
355 | goto err_net; | |
356 | } | |
357 | ||
358 | /* | |
359 | * Kill the callback thread if it's no longer being used. | |
360 | */ | |
361 | void nfs_callback_down(int minorversion, struct net *net) | |
362 | { | |
363 | struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; | |
364 | struct svc_serv *serv; | |
365 | ||
366 | mutex_lock(&nfs_callback_mutex); | |
367 | serv = cb_info->serv; | |
368 | nfs_callback_down_net(minorversion, serv, net); | |
369 | cb_info->users--; | |
370 | if (cb_info->users == 0) { | |
371 | svc_get(serv); | |
372 | serv->sv_ops->svo_setup(serv, NULL, 0); | |
373 | svc_destroy(serv); | |
374 | dprintk("nfs_callback_down: service destroyed\n"); | |
375 | cb_info->serv = NULL; | |
376 | } | |
377 | mutex_unlock(&nfs_callback_mutex); | |
378 | } | |
379 | ||
380 | /* Boolean check of RPC_AUTH_GSS principal */ | |
381 | int | |
382 | check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp) | |
383 | { | |
384 | char *p = rqstp->rq_cred.cr_principal; | |
385 | ||
386 | if (rqstp->rq_authop->flavour != RPC_AUTH_GSS) | |
387 | return 1; | |
388 | ||
389 | /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */ | |
390 | if (clp->cl_minorversion != 0) | |
391 | return 0; | |
392 | /* | |
393 | * It might just be a normal user principal, in which case | |
394 | * userspace won't bother to tell us the name at all. | |
395 | */ | |
396 | if (p == NULL) | |
397 | return 0; | |
398 | ||
399 | /* | |
400 | * Did we get the acceptor from userland during the SETCLIENID | |
401 | * negotiation? | |
402 | */ | |
403 | if (clp->cl_acceptor) | |
404 | return !strcmp(p, clp->cl_acceptor); | |
405 | ||
406 | /* | |
407 | * Otherwise try to verify it using the cl_hostname. Note that this | |
408 | * doesn't work if a non-canonical hostname was used in the devname. | |
409 | */ | |
410 | ||
411 | /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */ | |
412 | ||
413 | if (memcmp(p, "nfs@", 4) != 0) | |
414 | return 0; | |
415 | p += 4; | |
416 | if (strcmp(p, clp->cl_hostname) != 0) | |
417 | return 0; | |
418 | return 1; | |
419 | } | |
420 | ||
421 | /* | |
422 | * pg_authenticate method for nfsv4 callback threads. | |
423 | * | |
424 | * The authflavor has been negotiated, so an incorrect flavor is a server | |
425 | * bug. Deny packets with incorrect authflavor. | |
426 | * | |
427 | * All other checking done after NFS decoding where the nfs_client can be | |
428 | * found in nfs4_callback_compound | |
429 | */ | |
430 | static int nfs_callback_authenticate(struct svc_rqst *rqstp) | |
431 | { | |
432 | switch (rqstp->rq_authop->flavour) { | |
433 | case RPC_AUTH_NULL: | |
434 | if (rqstp->rq_proc != CB_NULL) | |
435 | return SVC_DENIED; | |
436 | break; | |
437 | case RPC_AUTH_GSS: | |
438 | /* No RPC_AUTH_GSS support yet in NFSv4.1 */ | |
439 | if (svc_is_backchannel(rqstp)) | |
440 | return SVC_DENIED; | |
441 | } | |
442 | return SVC_OK; | |
443 | } | |
444 | ||
445 | /* | |
446 | * Define NFS4 callback program | |
447 | */ | |
448 | static const struct svc_version *nfs4_callback_version[] = { | |
449 | [1] = &nfs4_callback_version1, | |
450 | [4] = &nfs4_callback_version4, | |
451 | }; | |
452 | ||
453 | static struct svc_stat nfs4_callback_stats; | |
454 | ||
455 | static struct svc_program nfs4_callback_program = { | |
456 | .pg_prog = NFS4_CALLBACK, /* RPC service number */ | |
457 | .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */ | |
458 | .pg_vers = nfs4_callback_version, /* version table */ | |
459 | .pg_name = "NFSv4 callback", /* service name */ | |
460 | .pg_class = "nfs", /* authentication class */ | |
461 | .pg_stats = &nfs4_callback_stats, | |
462 | .pg_authenticate = nfs_callback_authenticate, | |
463 | .pg_init_request = svc_generic_init_request, | |
464 | .pg_rpcbind_set = svc_generic_rpcbind_set, | |
465 | }; |