1 /* 2 * linux/fs/nfs/callback.c 3 * 4 * Copyright (C) 2004 Trond Myklebust 5 * 6 * NFSv4 callback handling 7 */ 8 9 #include <linux/completion.h> 10 #include <linux/ip.h> 11 #include <linux/module.h> 12 #include <linux/sched/signal.h> 13 #include <linux/sunrpc/svc.h> 14 #include <linux/sunrpc/svcsock.h> 15 #include <linux/nfs_fs.h> 16 #include <linux/errno.h> 17 #include <linux/mutex.h> 18 #include <linux/freezer.h> 19 #include <linux/kthread.h> 20 #include <linux/sunrpc/svcauth_gss.h> 21 #include <linux/sunrpc/bc_xprt.h> 22 23 #include <net/inet_sock.h> 24 25 #include "nfs4_fs.h" 26 #include "callback.h" 27 #include "internal.h" 28 #include "netns.h" 29 30 #define NFSDBG_FACILITY NFSDBG_CALLBACK 31 32 struct nfs_callback_data { 33 unsigned int users; 34 struct svc_serv *serv; 35 }; 36 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; 40 41 static int nfs4_callback_up_net(struct svc_serv *serv, struct net *net) 42 { 43 int ret; 44 struct nfs_net *nn = net_generic(net, nfs_net_id); 45 46 ret = svc_create_xprt(serv, "tcp", net, PF_INET, 47 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS); 48 if (ret <= 0) 49 goto out_err; 50 nn->nfs_callback_tcpport = ret; 51 dprintk("NFS: Callback listener port = %u (af %u, net %p)\n", 52 nn->nfs_callback_tcpport, PF_INET, net); 53 54 ret = svc_create_xprt(serv, "tcp", net, PF_INET6, 55 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS); 56 if (ret > 0) { 57 nn->nfs_callback_tcpport6 = ret; 58 dprintk("NFS: Callback listener port = %u (af %u, net %p)\n", 59 nn->nfs_callback_tcpport6, PF_INET6, net); 60 } else if (ret != -EAFNOSUPPORT) 61 goto out_err; 62 return 0; 63 64 out_err: 65 return (ret) ? ret : -ENOMEM; 66 } 67 68 /* 69 * This is the NFSv4 callback kernel thread. 70 */ 71 static int 72 nfs4_callback_svc(void *vrqstp) 73 { 74 int err; 75 struct svc_rqst *rqstp = vrqstp; 76 77 set_freezable(); 78 79 while (!kthread_should_stop()) { 80 /* 81 * Listen for a request on the socket 82 */ 83 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT); 84 if (err == -EAGAIN || err == -EINTR) 85 continue; 86 svc_process(rqstp); 87 } 88 return 0; 89 } 90 91 #if defined(CONFIG_NFS_V4_1) 92 /* 93 * The callback service for NFSv4.1 callbacks 94 */ 95 static int 96 nfs41_callback_svc(void *vrqstp) 97 { 98 struct svc_rqst *rqstp = vrqstp; 99 struct svc_serv *serv = rqstp->rq_server; 100 struct rpc_rqst *req; 101 int error; 102 DEFINE_WAIT(wq); 103 104 set_freezable(); 105 106 while (!kthread_should_stop()) { 107 if (try_to_freeze()) 108 continue; 109 110 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE); 111 spin_lock_bh(&serv->sv_cb_lock); 112 if (!list_empty(&serv->sv_cb_list)) { 113 req = list_first_entry(&serv->sv_cb_list, 114 struct rpc_rqst, rq_bc_list); 115 list_del(&req->rq_bc_list); 116 spin_unlock_bh(&serv->sv_cb_lock); 117 finish_wait(&serv->sv_cb_waitq, &wq); 118 dprintk("Invoking bc_svc_process()\n"); 119 error = bc_svc_process(serv, req, rqstp); 120 dprintk("bc_svc_process() returned w/ error code= %d\n", 121 error); 122 } else { 123 spin_unlock_bh(&serv->sv_cb_lock); 124 schedule(); 125 finish_wait(&serv->sv_cb_waitq, &wq); 126 } 127 flush_signals(current); 128 } 129 return 0; 130 } 131 132 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, 133 struct svc_serv *serv) 134 { 135 if (minorversion) 136 /* 137 * Save the svc_serv in the transport so that it can 138 * be referenced when the session backchannel is initialized 139 */ 140 xprt->bc_serv = serv; 141 } 142 #else 143 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, 144 struct svc_serv *serv) 145 { 146 } 147 #endif /* CONFIG_NFS_V4_1 */ 148 149 static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt, 150 struct svc_serv *serv) 151 { 152 int nrservs = nfs_callback_nr_threads; 153 int ret; 154 155 nfs_callback_bc_serv(minorversion, xprt, serv); 156 157 if (nrservs < NFS4_MIN_NR_CALLBACK_THREADS) 158 nrservs = NFS4_MIN_NR_CALLBACK_THREADS; 159 160 if (serv->sv_nrthreads-1 == nrservs) 161 return 0; 162 163 ret = serv->sv_ops->svo_setup(serv, NULL, nrservs); 164 if (ret) { 165 serv->sv_ops->svo_setup(serv, NULL, 0); 166 return ret; 167 } 168 dprintk("nfs_callback_up: service started\n"); 169 return 0; 170 } 171 172 static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net) 173 { 174 struct nfs_net *nn = net_generic(net, nfs_net_id); 175 176 if (--nn->cb_users[minorversion]) 177 return; 178 179 dprintk("NFS: destroy per-net callback data; net=%p\n", net); 180 svc_shutdown_net(serv, net); 181 } 182 183 static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, 184 struct net *net, struct rpc_xprt *xprt) 185 { 186 struct nfs_net *nn = net_generic(net, nfs_net_id); 187 int ret; 188 189 if (nn->cb_users[minorversion]++) 190 return 0; 191 192 dprintk("NFS: create per-net callback data; net=%p\n", net); 193 194 ret = svc_bind(serv, net); 195 if (ret < 0) { 196 printk(KERN_WARNING "NFS: bind callback service failed\n"); 197 goto err_bind; 198 } 199 200 ret = -EPROTONOSUPPORT; 201 if (!IS_ENABLED(CONFIG_NFS_V4_1) || minorversion == 0) 202 ret = nfs4_callback_up_net(serv, net); 203 else if (xprt->ops->bc_up) 204 ret = xprt->ops->bc_up(serv, net); 205 206 if (ret < 0) { 207 printk(KERN_ERR "NFS: callback service start failed\n"); 208 goto err_socks; 209 } 210 return 0; 211 212 err_socks: 213 svc_rpcb_cleanup(serv, net); 214 err_bind: 215 nn->cb_users[minorversion]--; 216 dprintk("NFS: Couldn't create callback socket: err = %d; " 217 "net = %p\n", ret, net); 218 return ret; 219 } 220 221 static struct svc_serv_ops nfs40_cb_sv_ops = { 222 .svo_function = nfs4_callback_svc, 223 .svo_enqueue_xprt = svc_xprt_do_enqueue, 224 .svo_setup = svc_set_num_threads, 225 .svo_module = THIS_MODULE, 226 }; 227 #if defined(CONFIG_NFS_V4_1) 228 static struct svc_serv_ops nfs41_cb_sv_ops = { 229 .svo_function = nfs41_callback_svc, 230 .svo_enqueue_xprt = svc_xprt_do_enqueue, 231 .svo_setup = svc_set_num_threads, 232 .svo_module = THIS_MODULE, 233 }; 234 235 static struct svc_serv_ops *nfs4_cb_sv_ops[] = { 236 [0] = &nfs40_cb_sv_ops, 237 [1] = &nfs41_cb_sv_ops, 238 }; 239 #else 240 static struct svc_serv_ops *nfs4_cb_sv_ops[] = { 241 [0] = &nfs40_cb_sv_ops, 242 [1] = NULL, 243 }; 244 #endif 245 246 static struct svc_serv *nfs_callback_create_svc(int minorversion) 247 { 248 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 249 struct svc_serv *serv; 250 struct svc_serv_ops *sv_ops; 251 252 /* 253 * Check whether we're already up and running. 254 */ 255 if (cb_info->serv) { 256 /* 257 * Note: increase service usage, because later in case of error 258 * svc_destroy() will be called. 259 */ 260 svc_get(cb_info->serv); 261 return cb_info->serv; 262 } 263 264 switch (minorversion) { 265 case 0: 266 sv_ops = nfs4_cb_sv_ops[0]; 267 break; 268 default: 269 sv_ops = nfs4_cb_sv_ops[1]; 270 } 271 272 if (sv_ops == NULL) 273 return ERR_PTR(-ENOTSUPP); 274 275 /* 276 * Sanity check: if there's no task, 277 * we should be the first user ... 278 */ 279 if (cb_info->users) 280 printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n", 281 cb_info->users); 282 283 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, sv_ops); 284 if (!serv) { 285 printk(KERN_ERR "nfs_callback_create_svc: create service failed\n"); 286 return ERR_PTR(-ENOMEM); 287 } 288 cb_info->serv = serv; 289 /* As there is only one thread we need to over-ride the 290 * default maximum of 80 connections 291 */ 292 serv->sv_maxconn = 1024; 293 dprintk("nfs_callback_create_svc: service created\n"); 294 return serv; 295 } 296 297 /* 298 * Bring up the callback thread if it is not already up. 299 */ 300 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt) 301 { 302 struct svc_serv *serv; 303 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 304 int ret; 305 struct net *net = xprt->xprt_net; 306 307 mutex_lock(&nfs_callback_mutex); 308 309 serv = nfs_callback_create_svc(minorversion); 310 if (IS_ERR(serv)) { 311 ret = PTR_ERR(serv); 312 goto err_create; 313 } 314 315 ret = nfs_callback_up_net(minorversion, serv, net, xprt); 316 if (ret < 0) 317 goto err_net; 318 319 ret = nfs_callback_start_svc(minorversion, xprt, serv); 320 if (ret < 0) 321 goto err_start; 322 323 cb_info->users++; 324 /* 325 * svc_create creates the svc_serv with sv_nrthreads == 1, and then 326 * svc_prepare_thread increments that. So we need to call svc_destroy 327 * on both success and failure so that the refcount is 1 when the 328 * thread exits. 329 */ 330 err_net: 331 if (!cb_info->users) 332 cb_info->serv = NULL; 333 svc_destroy(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 serv->sv_ops->svo_setup(serv, NULL, 0); 359 svc_destroy(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 switch (rqstp->rq_authop->flavour) { 419 case RPC_AUTH_NULL: 420 if (rqstp->rq_proc != CB_NULL) 421 return SVC_DENIED; 422 break; 423 case RPC_AUTH_GSS: 424 /* No RPC_AUTH_GSS support yet in NFSv4.1 */ 425 if (svc_is_backchannel(rqstp)) 426 return SVC_DENIED; 427 } 428 return SVC_OK; 429 } 430 431 /* 432 * Define NFS4 callback program 433 */ 434 static struct svc_version *nfs4_callback_version[] = { 435 [1] = &nfs4_callback_version1, 436 [4] = &nfs4_callback_version4, 437 }; 438 439 static struct svc_stat nfs4_callback_stats; 440 441 static struct svc_program nfs4_callback_program = { 442 .pg_prog = NFS4_CALLBACK, /* RPC service number */ 443 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */ 444 .pg_vers = nfs4_callback_version, /* version table */ 445 .pg_name = "NFSv4 callback", /* service name */ 446 .pg_class = "nfs", /* authentication class */ 447 .pg_stats = &nfs4_callback_stats, 448 .pg_authenticate = nfs_callback_authenticate, 449 }; 450