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_kthread_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_kthread_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 == nrservs) 173 return 0; 174 175 ret = svc_set_num_threads(serv, NULL, nrservs); 176 if (ret) { 177 svc_set_num_threads(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_module = THIS_MODULE, 239 }; 240 #if defined(CONFIG_NFS_V4_1) 241 static const struct svc_serv_ops nfs41_cb_sv_ops = { 242 .svo_function = nfs41_callback_svc, 243 .svo_enqueue_xprt = svc_xprt_do_enqueue, 244 .svo_module = THIS_MODULE, 245 }; 246 247 static const struct svc_serv_ops *nfs4_cb_sv_ops[] = { 248 [0] = &nfs40_cb_sv_ops, 249 [1] = &nfs41_cb_sv_ops, 250 }; 251 #else 252 static const struct svc_serv_ops *nfs4_cb_sv_ops[] = { 253 [0] = &nfs40_cb_sv_ops, 254 [1] = NULL, 255 }; 256 #endif 257 258 static struct svc_serv *nfs_callback_create_svc(int minorversion) 259 { 260 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 261 const struct svc_serv_ops *sv_ops; 262 struct svc_serv *serv; 263 264 /* 265 * Check whether we're already up and running. 266 */ 267 if (cb_info->serv) 268 return svc_get(cb_info->serv); 269 270 switch (minorversion) { 271 case 0: 272 sv_ops = nfs4_cb_sv_ops[0]; 273 break; 274 default: 275 sv_ops = nfs4_cb_sv_ops[1]; 276 } 277 278 if (sv_ops == NULL) 279 return ERR_PTR(-ENOTSUPP); 280 281 /* 282 * Sanity check: if there's no task, 283 * we should be the first user ... 284 */ 285 if (cb_info->users) 286 printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n", 287 cb_info->users); 288 289 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, sv_ops); 290 if (!serv) { 291 printk(KERN_ERR "nfs_callback_create_svc: create service failed\n"); 292 return ERR_PTR(-ENOMEM); 293 } 294 cb_info->serv = serv; 295 /* As there is only one thread we need to over-ride the 296 * default maximum of 80 connections 297 */ 298 serv->sv_maxconn = 1024; 299 dprintk("nfs_callback_create_svc: service created\n"); 300 return serv; 301 } 302 303 /* 304 * Bring up the callback thread if it is not already up. 305 */ 306 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt) 307 { 308 struct svc_serv *serv; 309 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 310 int ret; 311 struct net *net = xprt->xprt_net; 312 313 mutex_lock(&nfs_callback_mutex); 314 315 serv = nfs_callback_create_svc(minorversion); 316 if (IS_ERR(serv)) { 317 ret = PTR_ERR(serv); 318 goto err_create; 319 } 320 321 ret = nfs_callback_up_net(minorversion, serv, net, xprt); 322 if (ret < 0) 323 goto err_net; 324 325 ret = nfs_callback_start_svc(minorversion, xprt, serv); 326 if (ret < 0) 327 goto err_start; 328 329 cb_info->users++; 330 err_net: 331 if (!cb_info->users) 332 cb_info->serv = NULL; 333 svc_put(serv); 334 err_create: 335 mutex_unlock(&nfs_callback_mutex); 336 return ret; 337 338 err_start: 339 nfs_callback_down_net(minorversion, serv, net); 340 dprintk("NFS: Couldn't create server thread; err = %d\n", ret); 341 goto err_net; 342 } 343 344 /* 345 * Kill the callback thread if it's no longer being used. 346 */ 347 void nfs_callback_down(int minorversion, struct net *net) 348 { 349 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 350 struct svc_serv *serv; 351 352 mutex_lock(&nfs_callback_mutex); 353 serv = cb_info->serv; 354 nfs_callback_down_net(minorversion, serv, net); 355 cb_info->users--; 356 if (cb_info->users == 0) { 357 svc_get(serv); 358 svc_set_num_threads(serv, NULL, 0); 359 svc_put(serv); 360 dprintk("nfs_callback_down: service destroyed\n"); 361 cb_info->serv = NULL; 362 } 363 mutex_unlock(&nfs_callback_mutex); 364 } 365 366 /* Boolean check of RPC_AUTH_GSS principal */ 367 int 368 check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp) 369 { 370 char *p = rqstp->rq_cred.cr_principal; 371 372 if (rqstp->rq_authop->flavour != RPC_AUTH_GSS) 373 return 1; 374 375 /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */ 376 if (clp->cl_minorversion != 0) 377 return 0; 378 /* 379 * It might just be a normal user principal, in which case 380 * userspace won't bother to tell us the name at all. 381 */ 382 if (p == NULL) 383 return 0; 384 385 /* 386 * Did we get the acceptor from userland during the SETCLIENID 387 * negotiation? 388 */ 389 if (clp->cl_acceptor) 390 return !strcmp(p, clp->cl_acceptor); 391 392 /* 393 * Otherwise try to verify it using the cl_hostname. Note that this 394 * doesn't work if a non-canonical hostname was used in the devname. 395 */ 396 397 /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */ 398 399 if (memcmp(p, "nfs@", 4) != 0) 400 return 0; 401 p += 4; 402 if (strcmp(p, clp->cl_hostname) != 0) 403 return 0; 404 return 1; 405 } 406 407 /* 408 * pg_authenticate method for nfsv4 callback threads. 409 * 410 * The authflavor has been negotiated, so an incorrect flavor is a server 411 * bug. Deny packets with incorrect authflavor. 412 * 413 * All other checking done after NFS decoding where the nfs_client can be 414 * found in nfs4_callback_compound 415 */ 416 static int nfs_callback_authenticate(struct svc_rqst *rqstp) 417 { 418 rqstp->rq_auth_stat = rpc_autherr_badcred; 419 420 switch (rqstp->rq_authop->flavour) { 421 case RPC_AUTH_NULL: 422 if (rqstp->rq_proc != CB_NULL) 423 return SVC_DENIED; 424 break; 425 case RPC_AUTH_GSS: 426 /* No RPC_AUTH_GSS support yet in NFSv4.1 */ 427 if (svc_is_backchannel(rqstp)) 428 return SVC_DENIED; 429 } 430 431 rqstp->rq_auth_stat = rpc_auth_ok; 432 return SVC_OK; 433 } 434 435 /* 436 * Define NFS4 callback program 437 */ 438 static const struct svc_version *nfs4_callback_version[] = { 439 [1] = &nfs4_callback_version1, 440 [4] = &nfs4_callback_version4, 441 }; 442 443 static struct svc_stat nfs4_callback_stats; 444 445 static struct svc_program nfs4_callback_program = { 446 .pg_prog = NFS4_CALLBACK, /* RPC service number */ 447 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */ 448 .pg_vers = nfs4_callback_version, /* version table */ 449 .pg_name = "NFSv4 callback", /* service name */ 450 .pg_class = "nfs", /* authentication class */ 451 .pg_stats = &nfs4_callback_stats, 452 .pg_authenticate = nfs_callback_authenticate, 453 .pg_init_request = svc_generic_init_request, 454 .pg_rpcbind_set = svc_generic_rpcbind_set, 455 }; 456