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