fs/nfs/callback.c

   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/sunrpc/svc.h>
  13 #include <linux/sunrpc/svcsock.h>
  14 #include <linux/nfs_fs.h>
  15 #include <linux/errno.h>
  16 #include <linux/mutex.h>
  17 #include <linux/freezer.h>
  18 #include <linux/kthread.h>
  19 #include <linux/sunrpc/svcauth_gss.h>
  20 #include <linux/sunrpc/bc_xprt.h>
  21
  22 #include <net/inet_sock.h>
  23
  24 #include "nfs4_fs.h"
  25 #include "callback.h"
  26 #include "internal.h"
  27 #include "netns.h"
  28
  29 #define NFSDBG_FACILITY NFSDBG_CALLBACK
  30
  31 struct nfs_callback_data {
  32         unsigned int users;
  33         struct svc_serv *serv;
  34         struct svc_rqst *rqst;
  35         struct task_struct *task;
  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         int ret;
  45         struct nfs_net *nn = net_generic(net, nfs_net_id);
  46
  47         ret = svc_create_xprt(serv, "tcp", net, PF_INET,
  48                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
  49         if (ret <= 0)
  50                 goto out_err;
  51         nn->nfs_callback_tcpport = ret;
  52         dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
  53                         nn->nfs_callback_tcpport, PF_INET, net);
  54
  55         ret = svc_create_xprt(serv, "tcp", net, PF_INET6,
  56                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
  57         if (ret > 0) {
  58                 nn->nfs_callback_tcpport6 = ret;
  59                 dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
  60                                 nn->nfs_callback_tcpport6, PF_INET6, net);
  61         } else if (ret != -EAFNOSUPPORT)
  62                 goto out_err;
  63         return 0;
  64
  65 out_err:
  66         return (ret) ? ret : -ENOMEM;
  67 }
  68
  69 /*
  70  * This is the NFSv4 callback kernel thread.
  71  */
  72 static int
  73 nfs4_callback_svc(void *vrqstp)
  74 {
  75         int err;
  76         struct svc_rqst *rqstp = vrqstp;
  77
  78         set_freezable();
  79
  80         while (!kthread_should_stop()) {
  81                 /*
  82                  * Listen for a request on the socket
  83                  */
  84                 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
  85                 if (err == -EAGAIN || err == -EINTR)
  86                         continue;
  87                 svc_process(rqstp);
  88         }
  89         return 0;
  90 }
  91
  92 /*
  93  * Prepare to bring up the NFSv4 callback service
  94  */
  95 static struct svc_rqst *
  96 nfs4_callback_up(struct svc_serv *serv)
  97 {
  98         return svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
  99 }
 100
 101 #if defined(CONFIG_NFS_V4_1)
 102 /*
 103  * The callback service for NFSv4.1 callbacks
 104  */
 105 static int
 106 nfs41_callback_svc(void *vrqstp)
 107 {
 108         struct svc_rqst *rqstp = vrqstp;
 109         struct svc_serv *serv = rqstp->rq_server;
 110         struct rpc_rqst *req;
 111         int error;
 112         DEFINE_WAIT(wq);
 113
 114         set_freezable();
 115
 116         while (!kthread_should_stop()) {
 117                 if (try_to_freeze())
 118                         continue;
 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                         schedule();
 135                         finish_wait(&serv->sv_cb_waitq, &wq);
 136                 }
 137                 flush_signals(current);
 138         }
 139         return 0;
 140 }
 141
 142 /*
 143  * Bring up the NFSv4.1 callback service
 144  */
 145 static struct svc_rqst *
 146 nfs41_callback_up(struct svc_serv *serv)
 147 {
 148         struct svc_rqst *rqstp;
 149
 150         INIT_LIST_HEAD(&serv->sv_cb_list);
 151         spin_lock_init(&serv->sv_cb_lock);
 152         init_waitqueue_head(&serv->sv_cb_waitq);
 153         rqstp = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
 154         dprintk("--> %s return %d\n", __func__, PTR_ERR_OR_ZERO(rqstp));
 155         return rqstp;
 156 }
 157
 158 static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
 159                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 160 {
 161         *rqstpp = nfs41_callback_up(serv);
 162         *callback_svc = nfs41_callback_svc;
 163 }
 164
 165 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 166                 struct svc_serv *serv)
 167 {
 168         if (minorversion)
 169                 /*
 170                  * Save the svc_serv in the transport so that it can
 171                  * be referenced when the session backchannel is initialized
 172                  */
 173                 xprt->bc_serv = serv;
 174 }
 175 #else
 176 static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
 177                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 178 {
 179         *rqstpp = ERR_PTR(-ENOTSUPP);
 180         *callback_svc = ERR_PTR(-ENOTSUPP);
 181 }
 182
 183 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 184                 struct svc_serv *serv)
 185 {
 186 }
 187 #endif /* CONFIG_NFS_V4_1 */
 188
 189 static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
 190                                   struct svc_serv *serv)
 191 {
 192         struct svc_rqst *rqstp;
 193         int (*callback_svc)(void *vrqstp);
 194         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 195         int ret;
 196
 197         nfs_callback_bc_serv(minorversion, xprt, serv);
 198
 199         if (cb_info->task)
 200                 return 0;
 201
 202         switch (minorversion) {
 203         case 0:
 204                 /* v4.0 callback setup */
 205                 rqstp = nfs4_callback_up(serv);
 206                 callback_svc = nfs4_callback_svc;
 207                 break;
 208         default:
 209                 nfs_minorversion_callback_svc_setup(serv,
 210                                 &rqstp, &callback_svc);
 211         }
 212
 213         if (IS_ERR(rqstp))
 214                 return PTR_ERR(rqstp);
 215
 216         svc_sock_update_bufs(serv);
 217
 218         cb_info->serv = serv;
 219         cb_info->rqst = rqstp;
 220         cb_info->task = kthread_create(callback_svc, cb_info->rqst,
 221                                     "nfsv4.%u-svc", minorversion);
 222         if (IS_ERR(cb_info->task)) {
 223                 ret = PTR_ERR(cb_info->task);
 224                 svc_exit_thread(cb_info->rqst);
 225                 cb_info->rqst = NULL;
 226                 cb_info->task = NULL;
 227                 return ret;
 228         }
 229         rqstp->rq_task = cb_info->task;
 230         wake_up_process(cb_info->task);
 231         dprintk("nfs_callback_up: service started\n");
 232         return 0;
 233 }
 234
 235 static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net)
 236 {
 237         struct nfs_net *nn = net_generic(net, nfs_net_id);
 238
 239         if (--nn->cb_users[minorversion])
 240                 return;
 241
 242         dprintk("NFS: destroy per-net callback data; net=%p\n", net);
 243         svc_shutdown_net(serv, net);
 244 }
 245
 246 static int nfs_callback_up_net(int minorversion, struct svc_serv *serv,
 247                                struct net *net, struct rpc_xprt *xprt)
 248 {
 249         struct nfs_net *nn = net_generic(net, nfs_net_id);
 250         int ret;
 251
 252         if (nn->cb_users[minorversion]++)
 253                 return 0;
 254
 255         dprintk("NFS: create per-net callback data; net=%p\n", net);
 256
 257         ret = svc_bind(serv, net);
 258         if (ret < 0) {
 259                 printk(KERN_WARNING "NFS: bind callback service failed\n");
 260                 goto err_bind;
 261         }
 262
 263         ret = -EPROTONOSUPPORT;
 264         if (!IS_ENABLED(CONFIG_NFS_V4_1) || minorversion == 0)
 265                 ret = nfs4_callback_up_net(serv, net);
 266         else if (xprt->ops->bc_up)
 267                 ret = xprt->ops->bc_up(serv, net);
 268
 269         if (ret < 0) {
 270                 printk(KERN_ERR "NFS: callback service start failed\n");
 271                 goto err_socks;
 272         }
 273         return 0;
 274
 275 err_socks:
 276         svc_rpcb_cleanup(serv, net);
 277 err_bind:
 278         nn->cb_users[minorversion]--;
 279         dprintk("NFS: Couldn't create callback socket: err = %d; "
 280                         "net = %p\n", ret, net);
 281         return ret;
 282 }
 283
 284 static struct svc_serv_ops nfs_cb_sv_ops = {
 285         .svo_enqueue_xprt       = svc_xprt_do_enqueue,
 286 };
 287
 288 static struct svc_serv *nfs_callback_create_svc(int minorversion)
 289 {
 290         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 291         struct svc_serv *serv;
 292
 293         /*
 294          * Check whether we're already up and running.
 295          */
 296         if (cb_info->task) {
 297                 /*
 298                  * Note: increase service usage, because later in case of error
 299                  * svc_destroy() will be called.
 300                  */
 301                 svc_get(cb_info->serv);
 302                 return cb_info->serv;
 303         }
 304
 305         /*
 306          * Sanity check: if there's no task,
 307          * we should be the first user ...
 308          */
 309         if (cb_info->users)
 310                 printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
 311                         cb_info->users);
 312
 313         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, &nfs_cb_sv_ops);
 314         if (!serv) {
 315                 printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
 316                 return ERR_PTR(-ENOMEM);
 317         }
 318         /* As there is only one thread we need to over-ride the
 319          * default maximum of 80 connections
 320          */
 321         serv->sv_maxconn = 1024;
 322         dprintk("nfs_callback_create_svc: service created\n");
 323         return serv;
 324 }
 325
 326 /*
 327  * Bring up the callback thread if it is not already up.
 328  */
 329 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
 330 {
 331         struct svc_serv *serv;
 332         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 333         int ret;
 334         struct net *net = xprt->xprt_net;
 335
 336         mutex_lock(&nfs_callback_mutex);
 337
 338         serv = nfs_callback_create_svc(minorversion);
 339         if (IS_ERR(serv)) {
 340                 ret = PTR_ERR(serv);
 341                 goto err_create;
 342         }
 343
 344         ret = nfs_callback_up_net(minorversion, serv, net, xprt);
 345         if (ret < 0)
 346                 goto err_net;
 347
 348         ret = nfs_callback_start_svc(minorversion, xprt, serv);
 349         if (ret < 0)
 350                 goto err_start;
 351
 352         cb_info->users++;
 353         /*
 354          * svc_create creates the svc_serv with sv_nrthreads == 1, and then
 355          * svc_prepare_thread increments that. So we need to call svc_destroy
 356          * on both success and failure so that the refcount is 1 when the
 357          * thread exits.
 358          */
 359 err_net:
 360         svc_destroy(serv);
 361 err_create:
 362         mutex_unlock(&nfs_callback_mutex);
 363         return ret;
 364
 365 err_start:
 366         nfs_callback_down_net(minorversion, serv, net);
 367         dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
 368         goto err_net;
 369 }
 370
 371 /*
 372  * Kill the callback thread if it's no longer being used.
 373  */
 374 void nfs_callback_down(int minorversion, struct net *net)
 375 {
 376         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 377
 378         mutex_lock(&nfs_callback_mutex);
 379         nfs_callback_down_net(minorversion, cb_info->serv, net);
 380         cb_info->users--;
 381         if (cb_info->users == 0 && cb_info->task != NULL) {
 382                 kthread_stop(cb_info->task);
 383                 dprintk("nfs_callback_down: service stopped\n");
 384                 svc_exit_thread(cb_info->rqst);
 385                 dprintk("nfs_callback_down: service destroyed\n");
 386                 cb_info->serv = NULL;
 387                 cb_info->rqst = NULL;
 388                 cb_info->task = NULL;
 389         }
 390         mutex_unlock(&nfs_callback_mutex);
 391 }
 392
 393 /* Boolean check of RPC_AUTH_GSS principal */
 394 int
 395 check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
 396 {
 397         char *p = rqstp->rq_cred.cr_principal;
 398
 399         if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
 400                 return 1;
 401
 402         /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
 403         if (clp->cl_minorversion != 0)
 404                 return 0;
 405         /*
 406          * It might just be a normal user principal, in which case
 407          * userspace won't bother to tell us the name at all.
 408          */
 409         if (p == NULL)
 410                 return 0;
 411
 412         /*
 413          * Did we get the acceptor from userland during the SETCLIENID
 414          * negotiation?
 415          */
 416         if (clp->cl_acceptor)
 417                 return !strcmp(p, clp->cl_acceptor);
 418
 419         /*
 420          * Otherwise try to verify it using the cl_hostname. Note that this
 421          * doesn't work if a non-canonical hostname was used in the devname.
 422          */
 423
 424         /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
 425
 426         if (memcmp(p, "nfs@", 4) != 0)
 427                 return 0;
 428         p += 4;
 429         if (strcmp(p, clp->cl_hostname) != 0)
 430                 return 0;
 431         return 1;
 432 }
 433
 434 /*
 435  * pg_authenticate method for nfsv4 callback threads.
 436  *
 437  * The authflavor has been negotiated, so an incorrect flavor is a server
 438  * bug. Deny packets with incorrect authflavor.
 439  *
 440  * All other checking done after NFS decoding where the nfs_client can be
 441  * found in nfs4_callback_compound
 442  */
 443 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 444 {
 445         switch (rqstp->rq_authop->flavour) {
 446         case RPC_AUTH_NULL:
 447                 if (rqstp->rq_proc != CB_NULL)
 448                         return SVC_DENIED;
 449                 break;
 450         case RPC_AUTH_GSS:
 451                 /* No RPC_AUTH_GSS support yet in NFSv4.1 */
 452                  if (svc_is_backchannel(rqstp))
 453                         return SVC_DENIED;
 454         }
 455         return SVC_OK;
 456 }
 457
 458 /*
 459  * Define NFS4 callback program
 460  */
 461 static struct svc_version *nfs4_callback_version[] = {
 462         [1] = &nfs4_callback_version1,
 463         [4] = &nfs4_callback_version4,
 464 };
 465
 466 static struct svc_stat nfs4_callback_stats;
 467
 468 static struct svc_program nfs4_callback_program = {
 469         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 470         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 471         .pg_vers = nfs4_callback_version,               /* version table */
 472         .pg_name = "NFSv4 callback",                    /* service name */
 473         .pg_class = "nfs",                              /* authentication class */
 474         .pg_stats = &nfs4_callback_stats,
 475         .pg_authenticate = nfs_callback_authenticate,
 476 };