1 // SPDX-License-Identifier: GPL-2.0
3 * linux/fs/nfs/callback.c
5 * Copyright (C) 2004 Trond Myklebust
7 * NFSv4 callback handling
10 #include <linux/completion.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/sunrpc/svcauth_gss.h>
21 #include <linux/sunrpc/bc_xprt.h>
23 #include <net/inet_sock.h>
30 #define NFSDBG_FACILITY NFSDBG_CALLBACK
32 struct nfs_callback_data {
34 struct svc_serv *serv;
37 static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
38 static DEFINE_MUTEX(nfs_callback_mutex);
39 static struct svc_program nfs4_callback_program;
41 static int nfs4_callback_up_net(struct svc_serv *serv, struct net *net)
43 const struct cred *cred = current_cred();
45 struct nfs_net *nn = net_generic(net, nfs_net_id);
47 ret = svc_xprt_create(serv, "tcp", net, PF_INET,
48 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS,
52 nn->nfs_callback_tcpport = ret;
53 dprintk("NFS: Callback listener port = %u (af %u, net %x)\n",
54 nn->nfs_callback_tcpport, PF_INET, net->ns.inum);
56 ret = svc_xprt_create(serv, "tcp", net, PF_INET6,
57 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS,
60 nn->nfs_callback_tcpport6 = ret;
61 dprintk("NFS: Callback listener port = %u (af %u, net %x)\n",
62 nn->nfs_callback_tcpport6, PF_INET6, net->ns.inum);
63 } else if (ret != -EAFNOSUPPORT)
68 return (ret) ? ret : -ENOMEM;
72 * This is the NFSv4 callback kernel thread.
75 nfs4_callback_svc(void *vrqstp)
77 struct svc_rqst *rqstp = vrqstp;
81 while (!kthread_freezable_should_stop(NULL))
84 svc_exit_thread(rqstp);
88 #if defined(CONFIG_NFS_V4_1)
90 * The callback service for NFSv4.1 callbacks
93 nfs41_callback_svc(void *vrqstp)
95 struct svc_rqst *rqstp = vrqstp;
96 struct svc_serv *serv = rqstp->rq_server;
103 while (!kthread_freezable_should_stop(NULL)) {
104 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_IDLE);
105 spin_lock_bh(&serv->sv_cb_lock);
106 if (!list_empty(&serv->sv_cb_list)) {
107 req = list_first_entry(&serv->sv_cb_list,
108 struct rpc_rqst, rq_bc_list);
109 list_del(&req->rq_bc_list);
110 spin_unlock_bh(&serv->sv_cb_lock);
111 finish_wait(&serv->sv_cb_waitq, &wq);
112 dprintk("Invoking bc_svc_process()\n");
113 error = bc_svc_process(serv, req, rqstp);
114 dprintk("bc_svc_process() returned w/ error code= %d\n",
117 spin_unlock_bh(&serv->sv_cb_lock);
118 if (!kthread_should_stop())
120 finish_wait(&serv->sv_cb_waitq, &wq);
124 svc_exit_thread(rqstp);
128 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
129 struct svc_serv *serv)
133 * Save the svc_serv in the transport so that it can
134 * be referenced when the session backchannel is initialized
136 xprt->bc_serv = serv;
139 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
140 struct svc_serv *serv)
143 #endif /* CONFIG_NFS_V4_1 */
145 static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
146 struct svc_serv *serv)
148 int nrservs = nfs_callback_nr_threads;
151 nfs_callback_bc_serv(minorversion, xprt, serv);
153 if (nrservs < NFS4_MIN_NR_CALLBACK_THREADS)
154 nrservs = NFS4_MIN_NR_CALLBACK_THREADS;
156 if (serv->sv_nrthreads == nrservs)
159 ret = svc_set_num_threads(serv, NULL, nrservs);
161 svc_set_num_threads(serv, NULL, 0);
164 dprintk("nfs_callback_up: service started\n");
168 static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net)
170 struct nfs_net *nn = net_generic(net, nfs_net_id);
172 if (--nn->cb_users[minorversion])
175 dprintk("NFS: destroy per-net callback data; net=%x\n", net->ns.inum);
176 svc_xprt_destroy_all(serv, net);
179 static int nfs_callback_up_net(int minorversion, struct svc_serv *serv,
180 struct net *net, struct rpc_xprt *xprt)
182 struct nfs_net *nn = net_generic(net, nfs_net_id);
185 if (nn->cb_users[minorversion]++)
188 dprintk("NFS: create per-net callback data; net=%x\n", net->ns.inum);
190 ret = svc_bind(serv, net);
192 printk(KERN_WARNING "NFS: bind callback service failed\n");
197 if (!IS_ENABLED(CONFIG_NFS_V4_1) || minorversion == 0)
198 ret = nfs4_callback_up_net(serv, net);
199 else if (xprt->ops->bc_setup)
200 set_bc_enabled(serv);
202 ret = -EPROTONOSUPPORT;
205 printk(KERN_ERR "NFS: callback service start failed\n");
211 svc_rpcb_cleanup(serv, net);
213 nn->cb_users[minorversion]--;
214 dprintk("NFS: Couldn't create callback socket: err = %d; "
215 "net = %x\n", ret, net->ns.inum);
219 static struct svc_serv *nfs_callback_create_svc(int minorversion)
221 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
222 int (*threadfn)(void *data);
223 struct svc_serv *serv;
226 * Check whether we're already up and running.
229 return svc_get(cb_info->serv);
232 * Sanity check: if there's no task,
233 * we should be the first user ...
236 printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
239 threadfn = nfs4_callback_svc;
240 #if defined(CONFIG_NFS_V4_1)
242 threadfn = nfs41_callback_svc;
245 return ERR_PTR(-ENOTSUPP);
247 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE,
250 printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
251 return ERR_PTR(-ENOMEM);
253 cb_info->serv = serv;
254 /* As there is only one thread we need to over-ride the
255 * default maximum of 80 connections
257 serv->sv_maxconn = 1024;
258 dprintk("nfs_callback_create_svc: service created\n");
263 * Bring up the callback thread if it is not already up.
265 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
267 struct svc_serv *serv;
268 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
270 struct net *net = xprt->xprt_net;
272 mutex_lock(&nfs_callback_mutex);
274 serv = nfs_callback_create_svc(minorversion);
280 ret = nfs_callback_up_net(minorversion, serv, net, xprt);
284 ret = nfs_callback_start_svc(minorversion, xprt, serv);
291 cb_info->serv = NULL;
294 mutex_unlock(&nfs_callback_mutex);
298 nfs_callback_down_net(minorversion, serv, net);
299 dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
304 * Kill the callback thread if it's no longer being used.
306 void nfs_callback_down(int minorversion, struct net *net)
308 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
309 struct svc_serv *serv;
311 mutex_lock(&nfs_callback_mutex);
312 serv = cb_info->serv;
313 nfs_callback_down_net(minorversion, serv, net);
315 if (cb_info->users == 0) {
317 svc_set_num_threads(serv, NULL, 0);
319 dprintk("nfs_callback_down: service destroyed\n");
320 cb_info->serv = NULL;
322 mutex_unlock(&nfs_callback_mutex);
325 /* Boolean check of RPC_AUTH_GSS principal */
327 check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
329 char *p = rqstp->rq_cred.cr_principal;
331 if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
334 /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
335 if (clp->cl_minorversion != 0)
338 * It might just be a normal user principal, in which case
339 * userspace won't bother to tell us the name at all.
345 * Did we get the acceptor from userland during the SETCLIENID
348 if (clp->cl_acceptor)
349 return !strcmp(p, clp->cl_acceptor);
352 * Otherwise try to verify it using the cl_hostname. Note that this
353 * doesn't work if a non-canonical hostname was used in the devname.
356 /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
358 if (memcmp(p, "nfs@", 4) != 0)
361 if (strcmp(p, clp->cl_hostname) != 0)
367 * pg_authenticate method for nfsv4 callback threads.
369 * The authflavor has been negotiated, so an incorrect flavor is a server
370 * bug. Deny packets with incorrect authflavor.
372 * All other checking done after NFS decoding where the nfs_client can be
373 * found in nfs4_callback_compound
375 static enum svc_auth_status nfs_callback_authenticate(struct svc_rqst *rqstp)
377 rqstp->rq_auth_stat = rpc_autherr_badcred;
379 switch (rqstp->rq_authop->flavour) {
381 if (rqstp->rq_proc != CB_NULL)
385 /* No RPC_AUTH_GSS support yet in NFSv4.1 */
386 if (svc_is_backchannel(rqstp))
390 rqstp->rq_auth_stat = rpc_auth_ok;
395 * Define NFS4 callback program
397 static const struct svc_version *nfs4_callback_version[] = {
398 [1] = &nfs4_callback_version1,
399 [4] = &nfs4_callback_version4,
402 static struct svc_stat nfs4_callback_stats;
404 static struct svc_program nfs4_callback_program = {
405 .pg_prog = NFS4_CALLBACK, /* RPC service number */
406 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */
407 .pg_vers = nfs4_callback_version, /* version table */
408 .pg_name = "NFSv4 callback", /* service name */
409 .pg_class = "nfs", /* authentication class */
410 .pg_stats = &nfs4_callback_stats,
411 .pg_authenticate = nfs_callback_authenticate,
412 .pg_init_request = svc_generic_init_request,
413 .pg_rpcbind_set = svc_generic_rpcbind_set,