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 };
  35
  36 static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
  37 static DEFINE_MUTEX(nfs_callback_mutex);
  38 static struct svc_program nfs4_callback_program;
  39
  40 static int nfs4_callback_up_net(struct svc_serv *serv, struct net *net)
  41 {
  42         int ret;
  43         struct nfs_net *nn = net_generic(net, nfs_net_id);
  44
  45         ret = svc_create_xprt(serv, "tcp", net, PF_INET,
  46                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
  47         if (ret <= 0)
  48                 goto out_err;
  49         nn->nfs_callback_tcpport = ret;
  50         dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
  51                         nn->nfs_callback_tcpport, PF_INET, net);
  52
  53         ret = svc_create_xprt(serv, "tcp", net, PF_INET6,
  54                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
  55         if (ret > 0) {
  56                 nn->nfs_callback_tcpport6 = ret;
  57                 dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
  58                                 nn->nfs_callback_tcpport6, PF_INET6, net);
  59         } else if (ret != -EAFNOSUPPORT)
  60                 goto out_err;
  61         return 0;
  62
  63 out_err:
  64         return (ret) ? ret : -ENOMEM;
  65 }
  66
  67 /*
  68  * This is the NFSv4 callback kernel thread.
  69  */
  70 static int
  71 nfs4_callback_svc(void *vrqstp)
  72 {
  73         int err;
  74         struct svc_rqst *rqstp = vrqstp;
  75
  76         set_freezable();
  77
  78         while (!kthread_should_stop()) {
  79                 /*
  80                  * Listen for a request on the socket
  81                  */
  82                 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
  83                 if (err == -EAGAIN || err == -EINTR)
  84                         continue;
  85                 svc_process(rqstp);
  86         }
  87         return 0;
  88 }
  89
  90 #if defined(CONFIG_NFS_V4_1)
  91 /*
  92  * The callback service for NFSv4.1 callbacks
  93  */
  94 static int
  95 nfs41_callback_svc(void *vrqstp)
  96 {
  97         struct svc_rqst *rqstp = vrqstp;
  98         struct svc_serv *serv = rqstp->rq_server;
  99         struct rpc_rqst *req;
 100         int error;
 101         DEFINE_WAIT(wq);
 102
 103         set_freezable();
 104
 105         while (!kthread_should_stop()) {
 106                 if (try_to_freeze())
 107                         continue;
 108
 109                 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
 110                 spin_lock_bh(&serv->sv_cb_lock);
 111                 if (!list_empty(&serv->sv_cb_list)) {
 112                         req = list_first_entry(&serv->sv_cb_list,
 113                                         struct rpc_rqst, rq_bc_list);
 114                         list_del(&req->rq_bc_list);
 115                         spin_unlock_bh(&serv->sv_cb_lock);
 116                         finish_wait(&serv->sv_cb_waitq, &wq);
 117                         dprintk("Invoking bc_svc_process()\n");
 118                         error = bc_svc_process(serv, req, rqstp);
 119                         dprintk("bc_svc_process() returned w/ error code= %d\n",
 120                                 error);
 121                 } else {
 122                         spin_unlock_bh(&serv->sv_cb_lock);
 123                         schedule();
 124                         finish_wait(&serv->sv_cb_waitq, &wq);
 125                 }
 126                 flush_signals(current);
 127         }
 128         return 0;
 129 }
 130
 131 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 132                 struct svc_serv *serv)
 133 {
 134         if (minorversion)
 135                 /*
 136                  * Save the svc_serv in the transport so that it can
 137                  * be referenced when the session backchannel is initialized
 138                  */
 139                 xprt->bc_serv = serv;
 140 }
 141 #else
 142 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 143                 struct svc_serv *serv)
 144 {
 145 }
 146 #endif /* CONFIG_NFS_V4_1 */
 147
 148 static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
 149                                   struct svc_serv *serv)
 150 {
 151         int nrservs = nfs_callback_nr_threads;
 152         int ret;
 153
 154         nfs_callback_bc_serv(minorversion, xprt, serv);
 155
 156         if (nrservs < NFS4_MIN_NR_CALLBACK_THREADS)
 157                 nrservs = NFS4_MIN_NR_CALLBACK_THREADS;
 158
 159         if (serv->sv_nrthreads-1 == nrservs)
 160                 return 0;
 161
 162         ret = serv->sv_ops->svo_setup(serv, NULL, nrservs);
 163         if (ret) {
 164                 serv->sv_ops->svo_setup(serv, NULL, 0);
 165                 return ret;
 166         }
 167         dprintk("nfs_callback_up: service started\n");
 168         return 0;
 169 }
 170
 171 static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net)
 172 {
 173         struct nfs_net *nn = net_generic(net, nfs_net_id);
 174
 175         if (--nn->cb_users[minorversion])
 176                 return;
 177
 178         dprintk("NFS: destroy per-net callback data; net=%p\n", net);
 179         svc_shutdown_net(serv, net);
 180 }
 181
 182 static int nfs_callback_up_net(int minorversion, struct svc_serv *serv,
 183                                struct net *net, struct rpc_xprt *xprt)
 184 {
 185         struct nfs_net *nn = net_generic(net, nfs_net_id);
 186         int ret;
 187
 188         if (nn->cb_users[minorversion]++)
 189                 return 0;
 190
 191         dprintk("NFS: create per-net callback data; net=%p\n", net);
 192
 193         ret = svc_bind(serv, net);
 194         if (ret < 0) {
 195                 printk(KERN_WARNING "NFS: bind callback service failed\n");
 196                 goto err_bind;
 197         }
 198
 199         ret = -EPROTONOSUPPORT;
 200         if (!IS_ENABLED(CONFIG_NFS_V4_1) || minorversion == 0)
 201                 ret = nfs4_callback_up_net(serv, net);
 202         else if (xprt->ops->bc_up)
 203                 ret = xprt->ops->bc_up(serv, net);
 204
 205         if (ret < 0) {
 206                 printk(KERN_ERR "NFS: callback service start failed\n");
 207                 goto err_socks;
 208         }
 209         return 0;
 210
 211 err_socks:
 212         svc_rpcb_cleanup(serv, net);
 213 err_bind:
 214         nn->cb_users[minorversion]--;
 215         dprintk("NFS: Couldn't create callback socket: err = %d; "
 216                         "net = %p\n", ret, net);
 217         return ret;
 218 }
 219
 220 static struct svc_serv_ops nfs40_cb_sv_ops = {
 221         .svo_function           = nfs4_callback_svc,
 222         .svo_enqueue_xprt       = svc_xprt_do_enqueue,
 223         .svo_setup              = svc_set_num_threads,
 224         .svo_module             = THIS_MODULE,
 225 };
 226 #if defined(CONFIG_NFS_V4_1)
 227 static struct svc_serv_ops nfs41_cb_sv_ops = {
 228         .svo_function           = nfs41_callback_svc,
 229         .svo_enqueue_xprt       = svc_xprt_do_enqueue,
 230         .svo_setup              = svc_set_num_threads,
 231         .svo_module             = THIS_MODULE,
 232 };
 233
 234 struct svc_serv_ops *nfs4_cb_sv_ops[] = {
 235         [0] = &nfs40_cb_sv_ops,
 236         [1] = &nfs41_cb_sv_ops,
 237 };
 238 #else
 239 struct svc_serv_ops *nfs4_cb_sv_ops[] = {
 240         [0] = &nfs40_cb_sv_ops,
 241         [1] = NULL,
 242 };
 243 #endif
 244
 245 static struct svc_serv *nfs_callback_create_svc(int minorversion)
 246 {
 247         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 248         struct svc_serv *serv;
 249         struct svc_serv_ops *sv_ops;
 250
 251         /*
 252          * Check whether we're already up and running.
 253          */
 254         if (cb_info->serv) {
 255                 /*
 256                  * Note: increase service usage, because later in case of error
 257                  * svc_destroy() will be called.
 258                  */
 259                 svc_get(cb_info->serv);
 260                 return cb_info->serv;
 261         }
 262
 263         switch (minorversion) {
 264         case 0:
 265                 sv_ops = nfs4_cb_sv_ops[0];
 266                 break;
 267         default:
 268                 sv_ops = nfs4_cb_sv_ops[1];
 269         }
 270
 271         if (sv_ops == NULL)
 272                 return ERR_PTR(-ENOTSUPP);
 273
 274         /*
 275          * Sanity check: if there's no task,
 276          * we should be the first user ...
 277          */
 278         if (cb_info->users)
 279                 printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
 280                         cb_info->users);
 281
 282         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, sv_ops);
 283         if (!serv) {
 284                 printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
 285                 return ERR_PTR(-ENOMEM);
 286         }
 287         cb_info->serv = serv;
 288         /* As there is only one thread we need to over-ride the
 289          * default maximum of 80 connections
 290          */
 291         serv->sv_maxconn = 1024;
 292         dprintk("nfs_callback_create_svc: service created\n");
 293         return serv;
 294 }
 295
 296 /*
 297  * Bring up the callback thread if it is not already up.
 298  */
 299 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
 300 {
 301         struct svc_serv *serv;
 302         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 303         int ret;
 304         struct net *net = xprt->xprt_net;
 305
 306         mutex_lock(&nfs_callback_mutex);
 307
 308         serv = nfs_callback_create_svc(minorversion);
 309         if (IS_ERR(serv)) {
 310                 ret = PTR_ERR(serv);
 311                 goto err_create;
 312         }
 313
 314         ret = nfs_callback_up_net(minorversion, serv, net, xprt);
 315         if (ret < 0)
 316                 goto err_net;
 317
 318         ret = nfs_callback_start_svc(minorversion, xprt, serv);
 319         if (ret < 0)
 320                 goto err_start;
 321
 322         cb_info->users++;
 323         /*
 324          * svc_create creates the svc_serv with sv_nrthreads == 1, and then
 325          * svc_prepare_thread increments that. So we need to call svc_destroy
 326          * on both success and failure so that the refcount is 1 when the
 327          * thread exits.
 328          */
 329 err_net:
 330         if (!cb_info->users)
 331                 cb_info->serv = NULL;
 332         svc_destroy(serv);
 333 err_create:
 334         mutex_unlock(&nfs_callback_mutex);
 335         return ret;
 336
 337 err_start:
 338         nfs_callback_down_net(minorversion, serv, net);
 339         dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
 340         goto err_net;
 341 }
 342
 343 /*
 344  * Kill the callback thread if it's no longer being used.
 345  */
 346 void nfs_callback_down(int minorversion, struct net *net)
 347 {
 348         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 349         struct svc_serv *serv;
 350
 351         mutex_lock(&nfs_callback_mutex);
 352         serv = cb_info->serv;
 353         nfs_callback_down_net(minorversion, serv, net);
 354         cb_info->users--;
 355         if (cb_info->users == 0) {
 356                 svc_get(serv);
 357                 serv->sv_ops->svo_setup(serv, NULL, 0);
 358                 svc_destroy(serv);
 359                 dprintk("nfs_callback_down: service destroyed\n");
 360                 cb_info->serv = NULL;
 361         }
 362         mutex_unlock(&nfs_callback_mutex);
 363 }
 364
 365 /* Boolean check of RPC_AUTH_GSS principal */
 366 int
 367 check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
 368 {
 369         char *p = rqstp->rq_cred.cr_principal;
 370
 371         if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
 372                 return 1;
 373
 374         /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
 375         if (clp->cl_minorversion != 0)
 376                 return 0;
 377         /*
 378          * It might just be a normal user principal, in which case
 379          * userspace won't bother to tell us the name at all.
 380          */
 381         if (p == NULL)
 382                 return 0;
 383
 384         /*
 385          * Did we get the acceptor from userland during the SETCLIENID
 386          * negotiation?
 387          */
 388         if (clp->cl_acceptor)
 389                 return !strcmp(p, clp->cl_acceptor);
 390
 391         /*
 392          * Otherwise try to verify it using the cl_hostname. Note that this
 393          * doesn't work if a non-canonical hostname was used in the devname.
 394          */
 395
 396         /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
 397
 398         if (memcmp(p, "nfs@", 4) != 0)
 399                 return 0;
 400         p += 4;
 401         if (strcmp(p, clp->cl_hostname) != 0)
 402                 return 0;
 403         return 1;
 404 }
 405
 406 /*
 407  * pg_authenticate method for nfsv4 callback threads.
 408  *
 409  * The authflavor has been negotiated, so an incorrect flavor is a server
 410  * bug. Deny packets with incorrect authflavor.
 411  *
 412  * All other checking done after NFS decoding where the nfs_client can be
 413  * found in nfs4_callback_compound
 414  */
 415 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 416 {
 417         switch (rqstp->rq_authop->flavour) {
 418         case RPC_AUTH_NULL:
 419                 if (rqstp->rq_proc != CB_NULL)
 420                         return SVC_DENIED;
 421                 break;
 422         case RPC_AUTH_GSS:
 423                 /* No RPC_AUTH_GSS support yet in NFSv4.1 */
 424                  if (svc_is_backchannel(rqstp))
 425                         return SVC_DENIED;
 426         }
 427         return SVC_OK;
 428 }
 429
 430 /*
 431  * Define NFS4 callback program
 432  */
 433 static struct svc_version *nfs4_callback_version[] = {
 434         [1] = &nfs4_callback_version1,
 435         [4] = &nfs4_callback_version4,
 436 };
 437
 438 static struct svc_stat nfs4_callback_stats;
 439
 440 static struct svc_program nfs4_callback_program = {
 441         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 442         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 443         .pg_vers = nfs4_callback_version,               /* version table */
 444         .pg_name = "NFSv4 callback",                    /* service name */
 445         .pg_class = "nfs",                              /* authentication class */
 446         .pg_stats = &nfs4_callback_stats,
 447         .pg_authenticate = nfs_callback_authenticate,
 448 };