net/sunrpc/rpcb_clnt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * In-kernel rpcbind client supporting versions 2, 3, and 4 of the rpcbind
   4  * protocol
   5  *
   6  * Based on RFC 1833: "Binding Protocols for ONC RPC Version 2" and
   7  * RFC 3530: "Network File System (NFS) version 4 Protocol"
   8  *
   9  * Original: Gilles Quillard, Bull Open Source, 2005 <gilles.quillard@bull.net>
  10  * Updated: Chuck Lever, Oracle Corporation, 2007 <chuck.lever@oracle.com>
  11  *
  12  * Descended from net/sunrpc/pmap_clnt.c,
  13  *  Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
  14  */
  15
  16 #include <linux/module.h>
  17
  18 #include <linux/types.h>
  19 #include <linux/socket.h>
  20 #include <linux/un.h>
  21 #include <linux/in.h>
  22 #include <linux/in6.h>
  23 #include <linux/kernel.h>
  24 #include <linux/errno.h>
  25 #include <linux/mutex.h>
  26 #include <linux/slab.h>
  27 #include <net/ipv6.h>
  28
  29 #include <linux/sunrpc/clnt.h>
  30 #include <linux/sunrpc/addr.h>
  31 #include <linux/sunrpc/sched.h>
  32 #include <linux/sunrpc/xprtsock.h>
  33
  34 #include <trace/events/sunrpc.h>
  35
  36 #include "netns.h"
  37
  38 #define RPCBIND_SOCK_PATHNAME   "/var/run/rpcbind.sock"
  39
  40 #define RPCBIND_PROGRAM         (100000u)
  41 #define RPCBIND_PORT            (111u)
  42
  43 #define RPCBVERS_2              (2u)
  44 #define RPCBVERS_3              (3u)
  45 #define RPCBVERS_4              (4u)
  46
  47 enum {
  48         RPCBPROC_NULL,
  49         RPCBPROC_SET,
  50         RPCBPROC_UNSET,
  51         RPCBPROC_GETPORT,
  52         RPCBPROC_GETADDR = 3,           /* alias for GETPORT */
  53         RPCBPROC_DUMP,
  54         RPCBPROC_CALLIT,
  55         RPCBPROC_BCAST = 5,             /* alias for CALLIT */
  56         RPCBPROC_GETTIME,
  57         RPCBPROC_UADDR2TADDR,
  58         RPCBPROC_TADDR2UADDR,
  59         RPCBPROC_GETVERSADDR,
  60         RPCBPROC_INDIRECT,
  61         RPCBPROC_GETADDRLIST,
  62         RPCBPROC_GETSTAT,
  63 };
  64
  65 /*
  66  * r_owner
  67  *
  68  * The "owner" is allowed to unset a service in the rpcbind database.
  69  *
  70  * For AF_LOCAL SET/UNSET requests, rpcbind treats this string as a
  71  * UID which it maps to a local user name via a password lookup.
  72  * In all other cases it is ignored.
  73  *
  74  * For SET/UNSET requests, user space provides a value, even for
  75  * network requests, and GETADDR uses an empty string.  We follow
  76  * those precedents here.
  77  */
  78 #define RPCB_OWNER_STRING       "0"
  79 #define RPCB_MAXOWNERLEN        sizeof(RPCB_OWNER_STRING)
  80
  81 /*
  82  * XDR data type sizes
  83  */
  84 #define RPCB_program_sz         (1)
  85 #define RPCB_version_sz         (1)
  86 #define RPCB_protocol_sz        (1)
  87 #define RPCB_port_sz            (1)
  88 #define RPCB_boolean_sz         (1)
  89
  90 #define RPCB_netid_sz           (1 + XDR_QUADLEN(RPCBIND_MAXNETIDLEN))
  91 #define RPCB_addr_sz            (1 + XDR_QUADLEN(RPCBIND_MAXUADDRLEN))
  92 #define RPCB_ownerstring_sz     (1 + XDR_QUADLEN(RPCB_MAXOWNERLEN))
  93
  94 /*
  95  * XDR argument and result sizes
  96  */
  97 #define RPCB_mappingargs_sz     (RPCB_program_sz + RPCB_version_sz + \
  98                                 RPCB_protocol_sz + RPCB_port_sz)
  99 #define RPCB_getaddrargs_sz     (RPCB_program_sz + RPCB_version_sz + \
 100                                 RPCB_netid_sz + RPCB_addr_sz + \
 101                                 RPCB_ownerstring_sz)
 102
 103 #define RPCB_getportres_sz      RPCB_port_sz
 104 #define RPCB_setres_sz          RPCB_boolean_sz
 105
 106 /*
 107  * Note that RFC 1833 does not put any size restrictions on the
 108  * address string returned by the remote rpcbind database.
 109  */
 110 #define RPCB_getaddrres_sz      RPCB_addr_sz
 111
 112 static void                     rpcb_getport_done(struct rpc_task *, void *);
 113 static void                     rpcb_map_release(void *data);
 114 static const struct rpc_program rpcb_program;
 115
 116 struct rpcbind_args {
 117         struct rpc_xprt *       r_xprt;
 118
 119         u32                     r_prog;
 120         u32                     r_vers;
 121         u32                     r_prot;
 122         unsigned short          r_port;
 123         const char *            r_netid;
 124         const char *            r_addr;
 125         const char *            r_owner;
 126
 127         int                     r_status;
 128 };
 129
 130 static const struct rpc_procinfo rpcb_procedures2[];
 131 static const struct rpc_procinfo rpcb_procedures3[];
 132 static const struct rpc_procinfo rpcb_procedures4[];
 133
 134 struct rpcb_info {
 135         u32                     rpc_vers;
 136         const struct rpc_procinfo *rpc_proc;
 137 };
 138
 139 static const struct rpcb_info rpcb_next_version[];
 140 static const struct rpcb_info rpcb_next_version6[];
 141
 142 static const struct rpc_call_ops rpcb_getport_ops = {
 143         .rpc_call_done          = rpcb_getport_done,
 144         .rpc_release            = rpcb_map_release,
 145 };
 146
 147 static void rpcb_wake_rpcbind_waiters(struct rpc_xprt *xprt, int status)
 148 {
 149         xprt_clear_binding(xprt);
 150         rpc_wake_up_status(&xprt->binding, status);
 151 }
 152
 153 static void rpcb_map_release(void *data)
 154 {
 155         struct rpcbind_args *map = data;
 156
 157         rpcb_wake_rpcbind_waiters(map->r_xprt, map->r_status);
 158         xprt_put(map->r_xprt);
 159         kfree(map->r_addr);
 160         kfree(map);
 161 }
 162
 163 static int rpcb_get_local(struct net *net)
 164 {
 165         int cnt;
 166         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 167
 168         spin_lock(&sn->rpcb_clnt_lock);
 169         if (sn->rpcb_users)
 170                 sn->rpcb_users++;
 171         cnt = sn->rpcb_users;
 172         spin_unlock(&sn->rpcb_clnt_lock);
 173
 174         return cnt;
 175 }
 176
 177 void rpcb_put_local(struct net *net)
 178 {
 179         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 180         struct rpc_clnt *clnt = sn->rpcb_local_clnt;
 181         struct rpc_clnt *clnt4 = sn->rpcb_local_clnt4;
 182         int shutdown = 0;
 183
 184         spin_lock(&sn->rpcb_clnt_lock);
 185         if (sn->rpcb_users) {
 186                 if (--sn->rpcb_users == 0) {
 187                         sn->rpcb_local_clnt = NULL;
 188                         sn->rpcb_local_clnt4 = NULL;
 189                 }
 190                 shutdown = !sn->rpcb_users;
 191         }
 192         spin_unlock(&sn->rpcb_clnt_lock);
 193
 194         if (shutdown) {
 195                 /*
 196                  * cleanup_rpcb_clnt - remove xprtsock's sysctls, unregister
 197                  */
 198                 if (clnt4)
 199                         rpc_shutdown_client(clnt4);
 200                 if (clnt)
 201                         rpc_shutdown_client(clnt);
 202         }
 203 }
 204
 205 static void rpcb_set_local(struct net *net, struct rpc_clnt *clnt,
 206                         struct rpc_clnt *clnt4,
 207                         bool is_af_local)
 208 {
 209         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 210
 211         /* Protected by rpcb_create_local_mutex */
 212         sn->rpcb_local_clnt = clnt;
 213         sn->rpcb_local_clnt4 = clnt4;
 214         sn->rpcb_is_af_local = is_af_local ? 1 : 0;
 215         smp_wmb();
 216         sn->rpcb_users = 1;
 217 }
 218
 219 /*
 220  * Returns zero on success, otherwise a negative errno value
 221  * is returned.
 222  */
 223 static int rpcb_create_local_unix(struct net *net)
 224 {
 225         static const struct sockaddr_un rpcb_localaddr_rpcbind = {
 226                 .sun_family             = AF_LOCAL,
 227                 .sun_path               = RPCBIND_SOCK_PATHNAME,
 228         };
 229         struct rpc_create_args args = {
 230                 .net            = net,
 231                 .protocol       = XPRT_TRANSPORT_LOCAL,
 232                 .address        = (struct sockaddr *)&rpcb_localaddr_rpcbind,
 233                 .addrsize       = sizeof(rpcb_localaddr_rpcbind),
 234                 .servername     = "localhost",
 235                 .program        = &rpcb_program,
 236                 .version        = RPCBVERS_2,
 237                 .authflavor     = RPC_AUTH_NULL,
 238                 .cred           = current_cred(),
 239                 /*
 240                  * We turn off the idle timeout to prevent the kernel
 241                  * from automatically disconnecting the socket.
 242                  * Otherwise, we'd have to cache the mount namespace
 243                  * of the caller and somehow pass that to the socket
 244                  * reconnect code.
 245                  */
 246                 .flags          = RPC_CLNT_CREATE_NO_IDLE_TIMEOUT,
 247         };
 248         struct rpc_clnt *clnt, *clnt4;
 249         int result = 0;
 250
 251         /*
 252          * Because we requested an RPC PING at transport creation time,
 253          * this works only if the user space portmapper is rpcbind, and
 254          * it's listening on AF_LOCAL on the named socket.
 255          */
 256         clnt = rpc_create(&args);
 257         if (IS_ERR(clnt)) {
 258                 result = PTR_ERR(clnt);
 259                 goto out;
 260         }
 261
 262         clnt4 = rpc_bind_new_program(clnt, &rpcb_program, RPCBVERS_4);
 263         if (IS_ERR(clnt4))
 264                 clnt4 = NULL;
 265
 266         rpcb_set_local(net, clnt, clnt4, true);
 267
 268 out:
 269         return result;
 270 }
 271
 272 /*
 273  * Returns zero on success, otherwise a negative errno value
 274  * is returned.
 275  */
 276 static int rpcb_create_local_net(struct net *net)
 277 {
 278         static const struct sockaddr_in rpcb_inaddr_loopback = {
 279                 .sin_family             = AF_INET,
 280                 .sin_addr.s_addr        = htonl(INADDR_LOOPBACK),
 281                 .sin_port               = htons(RPCBIND_PORT),
 282         };
 283         struct rpc_create_args args = {
 284                 .net            = net,
 285                 .protocol       = XPRT_TRANSPORT_TCP,
 286                 .address        = (struct sockaddr *)&rpcb_inaddr_loopback,
 287                 .addrsize       = sizeof(rpcb_inaddr_loopback),
 288                 .servername     = "localhost",
 289                 .program        = &rpcb_program,
 290                 .version        = RPCBVERS_2,
 291                 .authflavor     = RPC_AUTH_UNIX,
 292                 .cred           = current_cred(),
 293                 .flags          = RPC_CLNT_CREATE_NOPING,
 294         };
 295         struct rpc_clnt *clnt, *clnt4;
 296         int result = 0;
 297
 298         clnt = rpc_create(&args);
 299         if (IS_ERR(clnt)) {
 300                 result = PTR_ERR(clnt);
 301                 goto out;
 302         }
 303
 304         /*
 305          * This results in an RPC ping.  On systems running portmapper,
 306          * the v4 ping will fail.  Proceed anyway, but disallow rpcb
 307          * v4 upcalls.
 308          */
 309         clnt4 = rpc_bind_new_program(clnt, &rpcb_program, RPCBVERS_4);
 310         if (IS_ERR(clnt4))
 311                 clnt4 = NULL;
 312
 313         rpcb_set_local(net, clnt, clnt4, false);
 314
 315 out:
 316         return result;
 317 }
 318
 319 /*
 320  * Returns zero on success, otherwise a negative errno value
 321  * is returned.
 322  */
 323 int rpcb_create_local(struct net *net)
 324 {
 325         static DEFINE_MUTEX(rpcb_create_local_mutex);
 326         int result = 0;
 327
 328         if (rpcb_get_local(net))
 329                 return result;
 330
 331         mutex_lock(&rpcb_create_local_mutex);
 332         if (rpcb_get_local(net))
 333                 goto out;
 334
 335         if (rpcb_create_local_unix(net) != 0)
 336                 result = rpcb_create_local_net(net);
 337
 338 out:
 339         mutex_unlock(&rpcb_create_local_mutex);
 340         return result;
 341 }
 342
 343 static struct rpc_clnt *rpcb_create(struct net *net, const char *nodename,
 344                                     const char *hostname,
 345                                     struct sockaddr *srvaddr, size_t salen,
 346                                     int proto, u32 version,
 347                                     const struct cred *cred)
 348 {
 349         struct rpc_create_args args = {
 350                 .net            = net,
 351                 .protocol       = proto,
 352                 .address        = srvaddr,
 353                 .addrsize       = salen,
 354                 .servername     = hostname,
 355                 .nodename       = nodename,
 356                 .program        = &rpcb_program,
 357                 .version        = version,
 358                 .authflavor     = RPC_AUTH_UNIX,
 359                 .cred           = cred,
 360                 .flags          = (RPC_CLNT_CREATE_NOPING |
 361                                         RPC_CLNT_CREATE_NONPRIVPORT),
 362         };
 363
 364         switch (srvaddr->sa_family) {
 365         case AF_INET:
 366                 ((struct sockaddr_in *)srvaddr)->sin_port = htons(RPCBIND_PORT);
 367                 break;
 368         case AF_INET6:
 369                 ((struct sockaddr_in6 *)srvaddr)->sin6_port = htons(RPCBIND_PORT);
 370                 break;
 371         default:
 372                 return ERR_PTR(-EAFNOSUPPORT);
 373         }
 374
 375         return rpc_create(&args);
 376 }
 377
 378 static int rpcb_register_call(struct sunrpc_net *sn, struct rpc_clnt *clnt, struct rpc_message *msg, bool is_set)
 379 {
 380         int flags = RPC_TASK_NOCONNECT;
 381         int error, result = 0;
 382
 383         if (is_set || !sn->rpcb_is_af_local)
 384                 flags = RPC_TASK_SOFTCONN;
 385         msg->rpc_resp = &result;
 386
 387         error = rpc_call_sync(clnt, msg, flags);
 388         if (error < 0)
 389                 return error;
 390
 391         if (!result)
 392                 return -EACCES;
 393         return 0;
 394 }
 395
 396 /**
 397  * rpcb_register - set or unset a port registration with the local rpcbind svc
 398  * @net: target network namespace
 399  * @prog: RPC program number to bind
 400  * @vers: RPC version number to bind
 401  * @prot: transport protocol to register
 402  * @port: port value to register
 403  *
 404  * Returns zero if the registration request was dispatched successfully
 405  * and the rpcbind daemon returned success.  Otherwise, returns an errno
 406  * value that reflects the nature of the error (request could not be
 407  * dispatched, timed out, or rpcbind returned an error).
 408  *
 409  * RPC services invoke this function to advertise their contact
 410  * information via the system's rpcbind daemon.  RPC services
 411  * invoke this function once for each [program, version, transport]
 412  * tuple they wish to advertise.
 413  *
 414  * Callers may also unregister RPC services that are no longer
 415  * available by setting the passed-in port to zero.  This removes
 416  * all registered transports for [program, version] from the local
 417  * rpcbind database.
 418  *
 419  * This function uses rpcbind protocol version 2 to contact the
 420  * local rpcbind daemon.
 421  *
 422  * Registration works over both AF_INET and AF_INET6, and services
 423  * registered via this function are advertised as available for any
 424  * address.  If the local rpcbind daemon is listening on AF_INET6,
 425  * services registered via this function will be advertised on
 426  * IN6ADDR_ANY (ie available for all AF_INET and AF_INET6
 427  * addresses).
 428  */
 429 int rpcb_register(struct net *net, u32 prog, u32 vers, int prot, unsigned short port)
 430 {
 431         struct rpcbind_args map = {
 432                 .r_prog         = prog,
 433                 .r_vers         = vers,
 434                 .r_prot         = prot,
 435                 .r_port         = port,
 436         };
 437         struct rpc_message msg = {
 438                 .rpc_argp       = &map,
 439         };
 440         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 441         bool is_set = false;
 442
 443         trace_pmap_register(prog, vers, prot, port);
 444
 445         msg.rpc_proc = &rpcb_procedures2[RPCBPROC_UNSET];
 446         if (port != 0) {
 447                 msg.rpc_proc = &rpcb_procedures2[RPCBPROC_SET];
 448                 is_set = true;
 449         }
 450
 451         return rpcb_register_call(sn, sn->rpcb_local_clnt, &msg, is_set);
 452 }
 453
 454 /*
 455  * Fill in AF_INET family-specific arguments to register
 456  */
 457 static int rpcb_register_inet4(struct sunrpc_net *sn,
 458                                const struct sockaddr *sap,
 459                                struct rpc_message *msg)
 460 {
 461         const struct sockaddr_in *sin = (const struct sockaddr_in *)sap;
 462         struct rpcbind_args *map = msg->rpc_argp;
 463         unsigned short port = ntohs(sin->sin_port);
 464         bool is_set = false;
 465         int result;
 466
 467         map->r_addr = rpc_sockaddr2uaddr(sap, GFP_KERNEL);
 468
 469         msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
 470         if (port != 0) {
 471                 msg->rpc_proc = &rpcb_procedures4[RPCBPROC_SET];
 472                 is_set = true;
 473         }
 474
 475         result = rpcb_register_call(sn, sn->rpcb_local_clnt4, msg, is_set);
 476         kfree(map->r_addr);
 477         return result;
 478 }
 479
 480 /*
 481  * Fill in AF_INET6 family-specific arguments to register
 482  */
 483 static int rpcb_register_inet6(struct sunrpc_net *sn,
 484                                const struct sockaddr *sap,
 485                                struct rpc_message *msg)
 486 {
 487         const struct sockaddr_in6 *sin6 = (const struct sockaddr_in6 *)sap;
 488         struct rpcbind_args *map = msg->rpc_argp;
 489         unsigned short port = ntohs(sin6->sin6_port);
 490         bool is_set = false;
 491         int result;
 492
 493         map->r_addr = rpc_sockaddr2uaddr(sap, GFP_KERNEL);
 494
 495         msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
 496         if (port != 0) {
 497                 msg->rpc_proc = &rpcb_procedures4[RPCBPROC_SET];
 498                 is_set = true;
 499         }
 500
 501         result = rpcb_register_call(sn, sn->rpcb_local_clnt4, msg, is_set);
 502         kfree(map->r_addr);
 503         return result;
 504 }
 505
 506 static int rpcb_unregister_all_protofamilies(struct sunrpc_net *sn,
 507                                              struct rpc_message *msg)
 508 {
 509         struct rpcbind_args *map = msg->rpc_argp;
 510
 511         trace_rpcb_unregister(map->r_prog, map->r_vers, map->r_netid);
 512
 513         map->r_addr = "";
 514         msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
 515
 516         return rpcb_register_call(sn, sn->rpcb_local_clnt4, msg, false);
 517 }
 518
 519 /**
 520  * rpcb_v4_register - set or unset a port registration with the local rpcbind
 521  * @net: target network namespace
 522  * @program: RPC program number of service to (un)register
 523  * @version: RPC version number of service to (un)register
 524  * @address: address family, IP address, and port to (un)register
 525  * @netid: netid of transport protocol to (un)register
 526  *
 527  * Returns zero if the registration request was dispatched successfully
 528  * and the rpcbind daemon returned success.  Otherwise, returns an errno
 529  * value that reflects the nature of the error (request could not be
 530  * dispatched, timed out, or rpcbind returned an error).
 531  *
 532  * RPC services invoke this function to advertise their contact
 533  * information via the system's rpcbind daemon.  RPC services
 534  * invoke this function once for each [program, version, address,
 535  * netid] tuple they wish to advertise.
 536  *
 537  * Callers may also unregister RPC services that are registered at a
 538  * specific address by setting the port number in @address to zero.
 539  * They may unregister all registered protocol families at once for
 540  * a service by passing a NULL @address argument.  If @netid is ""
 541  * then all netids for [program, version, address] are unregistered.
 542  *
 543  * This function uses rpcbind protocol version 4 to contact the
 544  * local rpcbind daemon.  The local rpcbind daemon must support
 545  * version 4 of the rpcbind protocol in order for these functions
 546  * to register a service successfully.
 547  *
 548  * Supported netids include "udp" and "tcp" for UDP and TCP over
 549  * IPv4, and "udp6" and "tcp6" for UDP and TCP over IPv6,
 550  * respectively.
 551  *
 552  * The contents of @address determine the address family and the
 553  * port to be registered.  The usual practice is to pass INADDR_ANY
 554  * as the raw address, but specifying a non-zero address is also
 555  * supported by this API if the caller wishes to advertise an RPC
 556  * service on a specific network interface.
 557  *
 558  * Note that passing in INADDR_ANY does not create the same service
 559  * registration as IN6ADDR_ANY.  The former advertises an RPC
 560  * service on any IPv4 address, but not on IPv6.  The latter
 561  * advertises the service on all IPv4 and IPv6 addresses.
 562  */
 563 int rpcb_v4_register(struct net *net, const u32 program, const u32 version,
 564                      const struct sockaddr *address, const char *netid)
 565 {
 566         struct rpcbind_args map = {
 567                 .r_prog         = program,
 568                 .r_vers         = version,
 569                 .r_netid        = netid,
 570                 .r_owner        = RPCB_OWNER_STRING,
 571         };
 572         struct rpc_message msg = {
 573                 .rpc_argp       = &map,
 574         };
 575         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 576
 577         if (sn->rpcb_local_clnt4 == NULL)
 578                 return -EPROTONOSUPPORT;
 579
 580         if (address == NULL)
 581                 return rpcb_unregister_all_protofamilies(sn, &msg);
 582
 583         trace_rpcb_register(map.r_prog, map.r_vers, map.r_addr, map.r_netid);
 584
 585         switch (address->sa_family) {
 586         case AF_INET:
 587                 return rpcb_register_inet4(sn, address, &msg);
 588         case AF_INET6:
 589                 return rpcb_register_inet6(sn, address, &msg);
 590         }
 591
 592         return -EAFNOSUPPORT;
 593 }
 594
 595 static struct rpc_task *rpcb_call_async(struct rpc_clnt *rpcb_clnt,
 596                 struct rpcbind_args *map, const struct rpc_procinfo *proc)
 597 {
 598         struct rpc_message msg = {
 599                 .rpc_proc = proc,
 600                 .rpc_argp = map,
 601                 .rpc_resp = map,
 602         };
 603         struct rpc_task_setup task_setup_data = {
 604                 .rpc_client = rpcb_clnt,
 605                 .rpc_message = &msg,
 606                 .callback_ops = &rpcb_getport_ops,
 607                 .callback_data = map,
 608                 .flags = RPC_TASK_ASYNC | RPC_TASK_SOFTCONN,
 609         };
 610
 611         return rpc_run_task(&task_setup_data);
 612 }
 613
 614 /*
 615  * In the case where rpc clients have been cloned, we want to make
 616  * sure that we use the program number/version etc of the actual
 617  * owner of the xprt. To do so, we walk back up the tree of parents
 618  * to find whoever created the transport and/or whoever has the
 619  * autobind flag set.
 620  */
 621 static struct rpc_clnt *rpcb_find_transport_owner(struct rpc_clnt *clnt)
 622 {
 623         struct rpc_clnt *parent = clnt->cl_parent;
 624         struct rpc_xprt_switch *xps = rcu_access_pointer(clnt->cl_xpi.xpi_xpswitch);
 625
 626         while (parent != clnt) {
 627                 if (rcu_access_pointer(parent->cl_xpi.xpi_xpswitch) != xps)
 628                         break;
 629                 if (clnt->cl_autobind)
 630                         break;
 631                 clnt = parent;
 632                 parent = parent->cl_parent;
 633         }
 634         return clnt;
 635 }
 636
 637 /**
 638  * rpcb_getport_async - obtain the port for a given RPC service on a given host
 639  * @task: task that is waiting for portmapper request
 640  *
 641  * This one can be called for an ongoing RPC request, and can be used in
 642  * an async (rpciod) context.
 643  */
 644 void rpcb_getport_async(struct rpc_task *task)
 645 {
 646         struct rpc_clnt *clnt;
 647         const struct rpc_procinfo *proc;
 648         u32 bind_version;
 649         struct rpc_xprt *xprt;
 650         struct rpc_clnt *rpcb_clnt;
 651         struct rpcbind_args *map;
 652         struct rpc_task *child;
 653         struct sockaddr_storage addr;
 654         struct sockaddr *sap = (struct sockaddr *)&addr;
 655         size_t salen;
 656         int status;
 657
 658         rcu_read_lock();
 659         clnt = rpcb_find_transport_owner(task->tk_client);
 660         rcu_read_unlock();
 661         xprt = xprt_get(task->tk_xprt);
 662
 663         /* Put self on the wait queue to ensure we get notified if
 664          * some other task is already attempting to bind the port */
 665         rpc_sleep_on_timeout(&xprt->binding, task,
 666                         NULL, jiffies + xprt->bind_timeout);
 667
 668         if (xprt_test_and_set_binding(xprt)) {
 669                 xprt_put(xprt);
 670                 return;
 671         }
 672
 673         /* Someone else may have bound if we slept */
 674         if (xprt_bound(xprt)) {
 675                 status = 0;
 676                 goto bailout_nofree;
 677         }
 678
 679         /* Parent transport's destination address */
 680         salen = rpc_peeraddr(clnt, sap, sizeof(addr));
 681
 682         /* Don't ever use rpcbind v2 for AF_INET6 requests */
 683         switch (sap->sa_family) {
 684         case AF_INET:
 685                 proc = rpcb_next_version[xprt->bind_index].rpc_proc;
 686                 bind_version = rpcb_next_version[xprt->bind_index].rpc_vers;
 687                 break;
 688         case AF_INET6:
 689                 proc = rpcb_next_version6[xprt->bind_index].rpc_proc;
 690                 bind_version = rpcb_next_version6[xprt->bind_index].rpc_vers;
 691                 break;
 692         default:
 693                 status = -EAFNOSUPPORT;
 694                 goto bailout_nofree;
 695         }
 696         if (proc == NULL) {
 697                 xprt->bind_index = 0;
 698                 status = -EPFNOSUPPORT;
 699                 goto bailout_nofree;
 700         }
 701
 702         trace_rpcb_getport(clnt, task, bind_version);
 703
 704         rpcb_clnt = rpcb_create(xprt->xprt_net,
 705                                 clnt->cl_nodename,
 706                                 xprt->servername, sap, salen,
 707                                 xprt->prot, bind_version,
 708                                 clnt->cl_cred);
 709         if (IS_ERR(rpcb_clnt)) {
 710                 status = PTR_ERR(rpcb_clnt);
 711                 goto bailout_nofree;
 712         }
 713
 714         map = kzalloc(sizeof(struct rpcbind_args), GFP_NOFS);
 715         if (!map) {
 716                 status = -ENOMEM;
 717                 goto bailout_release_client;
 718         }
 719         map->r_prog = clnt->cl_prog;
 720         map->r_vers = clnt->cl_vers;
 721         map->r_prot = xprt->prot;
 722         map->r_port = 0;
 723         map->r_xprt = xprt;
 724         map->r_status = -EIO;
 725
 726         switch (bind_version) {
 727         case RPCBVERS_4:
 728         case RPCBVERS_3:
 729                 map->r_netid = xprt->address_strings[RPC_DISPLAY_NETID];
 730                 map->r_addr = rpc_sockaddr2uaddr(sap, GFP_NOFS);
 731                 if (!map->r_addr) {
 732                         status = -ENOMEM;
 733                         goto bailout_free_args;
 734                 }
 735                 map->r_owner = "";
 736                 break;
 737         case RPCBVERS_2:
 738                 map->r_addr = NULL;
 739                 break;
 740         default:
 741                 BUG();
 742         }
 743
 744         child = rpcb_call_async(rpcb_clnt, map, proc);
 745         rpc_release_client(rpcb_clnt);
 746
 747         xprt->stat.bind_count++;
 748         rpc_put_task(child);
 749         return;
 750
 751 bailout_free_args:
 752         kfree(map);
 753 bailout_release_client:
 754         rpc_release_client(rpcb_clnt);
 755 bailout_nofree:
 756         rpcb_wake_rpcbind_waiters(xprt, status);
 757         task->tk_status = status;
 758         xprt_put(xprt);
 759 }
 760 EXPORT_SYMBOL_GPL(rpcb_getport_async);
 761
 762 /*
 763  * Rpcbind child task calls this callback via tk_exit.
 764  */
 765 static void rpcb_getport_done(struct rpc_task *child, void *data)
 766 {
 767         struct rpcbind_args *map = data;
 768         struct rpc_xprt *xprt = map->r_xprt;
 769
 770         map->r_status = child->tk_status;
 771
 772         /* Garbage reply: retry with a lesser rpcbind version */
 773         if (map->r_status == -EIO)
 774                 map->r_status = -EPROTONOSUPPORT;
 775
 776         /* rpcbind server doesn't support this rpcbind protocol version */
 777         if (map->r_status == -EPROTONOSUPPORT)
 778                 xprt->bind_index++;
 779
 780         if (map->r_status < 0) {
 781                 /* rpcbind server not available on remote host? */
 782                 map->r_port = 0;
 783
 784         } else if (map->r_port == 0) {
 785                 /* Requested RPC service wasn't registered on remote host */
 786                 map->r_status = -EACCES;
 787         } else {
 788                 /* Succeeded */
 789                 map->r_status = 0;
 790         }
 791
 792         trace_rpcb_setport(child, map->r_status, map->r_port);
 793         xprt->ops->set_port(xprt, map->r_port);
 794         if (map->r_port)
 795                 xprt_set_bound(xprt);
 796 }
 797
 798 /*
 799  * XDR functions for rpcbind
 800  */
 801
 802 static void rpcb_enc_mapping(struct rpc_rqst *req, struct xdr_stream *xdr,
 803                              const void *data)
 804 {
 805         const struct rpcbind_args *rpcb = data;
 806         __be32 *p;
 807
 808         p = xdr_reserve_space(xdr, RPCB_mappingargs_sz << 2);
 809         *p++ = cpu_to_be32(rpcb->r_prog);
 810         *p++ = cpu_to_be32(rpcb->r_vers);
 811         *p++ = cpu_to_be32(rpcb->r_prot);
 812         *p   = cpu_to_be32(rpcb->r_port);
 813 }
 814
 815 static int rpcb_dec_getport(struct rpc_rqst *req, struct xdr_stream *xdr,
 816                             void *data)
 817 {
 818         struct rpcbind_args *rpcb = data;
 819         unsigned long port;
 820         __be32 *p;
 821
 822         rpcb->r_port = 0;
 823
 824         p = xdr_inline_decode(xdr, 4);
 825         if (unlikely(p == NULL))
 826                 return -EIO;
 827
 828         port = be32_to_cpup(p);
 829         if (unlikely(port > USHRT_MAX))
 830                 return -EIO;
 831
 832         rpcb->r_port = port;
 833         return 0;
 834 }
 835
 836 static int rpcb_dec_set(struct rpc_rqst *req, struct xdr_stream *xdr,
 837                         void *data)
 838 {
 839         unsigned int *boolp = data;
 840         __be32 *p;
 841
 842         p = xdr_inline_decode(xdr, 4);
 843         if (unlikely(p == NULL))
 844                 return -EIO;
 845
 846         *boolp = 0;
 847         if (*p != xdr_zero)
 848                 *boolp = 1;
 849         return 0;
 850 }
 851
 852 static void encode_rpcb_string(struct xdr_stream *xdr, const char *string,
 853                                const u32 maxstrlen)
 854 {
 855         __be32 *p;
 856         u32 len;
 857
 858         len = strlen(string);
 859         WARN_ON_ONCE(len > maxstrlen);
 860         if (len > maxstrlen)
 861                 /* truncate and hope for the best */
 862                 len = maxstrlen;
 863         p = xdr_reserve_space(xdr, 4 + len);
 864         xdr_encode_opaque(p, string, len);
 865 }
 866
 867 static void rpcb_enc_getaddr(struct rpc_rqst *req, struct xdr_stream *xdr,
 868                              const void *data)
 869 {
 870         const struct rpcbind_args *rpcb = data;
 871         __be32 *p;
 872
 873         p = xdr_reserve_space(xdr, (RPCB_program_sz + RPCB_version_sz) << 2);
 874         *p++ = cpu_to_be32(rpcb->r_prog);
 875         *p = cpu_to_be32(rpcb->r_vers);
 876
 877         encode_rpcb_string(xdr, rpcb->r_netid, RPCBIND_MAXNETIDLEN);
 878         encode_rpcb_string(xdr, rpcb->r_addr, RPCBIND_MAXUADDRLEN);
 879         encode_rpcb_string(xdr, rpcb->r_owner, RPCB_MAXOWNERLEN);
 880 }
 881
 882 static int rpcb_dec_getaddr(struct rpc_rqst *req, struct xdr_stream *xdr,
 883                             void *data)
 884 {
 885         struct rpcbind_args *rpcb = data;
 886         struct sockaddr_storage address;
 887         struct sockaddr *sap = (struct sockaddr *)&address;
 888         __be32 *p;
 889         u32 len;
 890
 891         rpcb->r_port = 0;
 892
 893         p = xdr_inline_decode(xdr, 4);
 894         if (unlikely(p == NULL))
 895                 goto out_fail;
 896         len = be32_to_cpup(p);
 897
 898         /*
 899          * If the returned universal address is a null string,
 900          * the requested RPC service was not registered.
 901          */
 902         if (len == 0)
 903                 return 0;
 904
 905         if (unlikely(len > RPCBIND_MAXUADDRLEN))
 906                 goto out_fail;
 907
 908         p = xdr_inline_decode(xdr, len);
 909         if (unlikely(p == NULL))
 910                 goto out_fail;
 911
 912         if (rpc_uaddr2sockaddr(req->rq_xprt->xprt_net, (char *)p, len,
 913                                 sap, sizeof(address)) == 0)
 914                 goto out_fail;
 915         rpcb->r_port = rpc_get_port(sap);
 916
 917         return 0;
 918
 919 out_fail:
 920         return -EIO;
 921 }
 922
 923 /*
 924  * Not all rpcbind procedures described in RFC 1833 are implemented
 925  * since the Linux kernel RPC code requires only these.
 926  */
 927
 928 static const struct rpc_procinfo rpcb_procedures2[] = {
 929         [RPCBPROC_SET] = {
 930                 .p_proc         = RPCBPROC_SET,
 931                 .p_encode       = rpcb_enc_mapping,
 932                 .p_decode       = rpcb_dec_set,
 933                 .p_arglen       = RPCB_mappingargs_sz,
 934                 .p_replen       = RPCB_setres_sz,
 935                 .p_statidx      = RPCBPROC_SET,
 936                 .p_timer        = 0,
 937                 .p_name         = "SET",
 938         },
 939         [RPCBPROC_UNSET] = {
 940                 .p_proc         = RPCBPROC_UNSET,
 941                 .p_encode       = rpcb_enc_mapping,
 942                 .p_decode       = rpcb_dec_set,
 943                 .p_arglen       = RPCB_mappingargs_sz,
 944                 .p_replen       = RPCB_setres_sz,
 945                 .p_statidx      = RPCBPROC_UNSET,
 946                 .p_timer        = 0,
 947                 .p_name         = "UNSET",
 948         },
 949         [RPCBPROC_GETPORT] = {
 950                 .p_proc         = RPCBPROC_GETPORT,
 951                 .p_encode       = rpcb_enc_mapping,
 952                 .p_decode       = rpcb_dec_getport,
 953                 .p_arglen       = RPCB_mappingargs_sz,
 954                 .p_replen       = RPCB_getportres_sz,
 955                 .p_statidx      = RPCBPROC_GETPORT,
 956                 .p_timer        = 0,
 957                 .p_name         = "GETPORT",
 958         },
 959 };
 960
 961 static const struct rpc_procinfo rpcb_procedures3[] = {
 962         [RPCBPROC_SET] = {
 963                 .p_proc         = RPCBPROC_SET,
 964                 .p_encode       = rpcb_enc_getaddr,
 965                 .p_decode       = rpcb_dec_set,
 966                 .p_arglen       = RPCB_getaddrargs_sz,
 967                 .p_replen       = RPCB_setres_sz,
 968                 .p_statidx      = RPCBPROC_SET,
 969                 .p_timer        = 0,
 970                 .p_name         = "SET",
 971         },
 972         [RPCBPROC_UNSET] = {
 973                 .p_proc         = RPCBPROC_UNSET,
 974                 .p_encode       = rpcb_enc_getaddr,
 975                 .p_decode       = rpcb_dec_set,
 976                 .p_arglen       = RPCB_getaddrargs_sz,
 977                 .p_replen       = RPCB_setres_sz,
 978                 .p_statidx      = RPCBPROC_UNSET,
 979                 .p_timer        = 0,
 980                 .p_name         = "UNSET",
 981         },
 982         [RPCBPROC_GETADDR] = {
 983                 .p_proc         = RPCBPROC_GETADDR,
 984                 .p_encode       = rpcb_enc_getaddr,
 985                 .p_decode       = rpcb_dec_getaddr,
 986                 .p_arglen       = RPCB_getaddrargs_sz,
 987                 .p_replen       = RPCB_getaddrres_sz,
 988                 .p_statidx      = RPCBPROC_GETADDR,
 989                 .p_timer        = 0,
 990                 .p_name         = "GETADDR",
 991         },
 992 };
 993
 994 static const struct rpc_procinfo rpcb_procedures4[] = {
 995         [RPCBPROC_SET] = {
 996                 .p_proc         = RPCBPROC_SET,
 997                 .p_encode       = rpcb_enc_getaddr,
 998                 .p_decode       = rpcb_dec_set,
 999                 .p_arglen       = RPCB_getaddrargs_sz,
1000                 .p_replen       = RPCB_setres_sz,
1001                 .p_statidx      = RPCBPROC_SET,
1002                 .p_timer        = 0,
1003                 .p_name         = "SET",
1004         },
1005         [RPCBPROC_UNSET] = {
1006                 .p_proc         = RPCBPROC_UNSET,
1007                 .p_encode       = rpcb_enc_getaddr,
1008                 .p_decode       = rpcb_dec_set,
1009                 .p_arglen       = RPCB_getaddrargs_sz,
1010                 .p_replen       = RPCB_setres_sz,
1011                 .p_statidx      = RPCBPROC_UNSET,
1012                 .p_timer        = 0,
1013                 .p_name         = "UNSET",
1014         },
1015         [RPCBPROC_GETADDR] = {
1016                 .p_proc         = RPCBPROC_GETADDR,
1017                 .p_encode       = rpcb_enc_getaddr,
1018                 .p_decode       = rpcb_dec_getaddr,
1019                 .p_arglen       = RPCB_getaddrargs_sz,
1020                 .p_replen       = RPCB_getaddrres_sz,
1021                 .p_statidx      = RPCBPROC_GETADDR,
1022                 .p_timer        = 0,
1023                 .p_name         = "GETADDR",
1024         },
1025 };
1026
1027 static const struct rpcb_info rpcb_next_version[] = {
1028         {
1029                 .rpc_vers       = RPCBVERS_2,
1030                 .rpc_proc       = &rpcb_procedures2[RPCBPROC_GETPORT],
1031         },
1032         {
1033                 .rpc_proc       = NULL,
1034         },
1035 };
1036
1037 static const struct rpcb_info rpcb_next_version6[] = {
1038         {
1039                 .rpc_vers       = RPCBVERS_4,
1040                 .rpc_proc       = &rpcb_procedures4[RPCBPROC_GETADDR],
1041         },
1042         {
1043                 .rpc_vers       = RPCBVERS_3,
1044                 .rpc_proc       = &rpcb_procedures3[RPCBPROC_GETADDR],
1045         },
1046         {
1047                 .rpc_proc       = NULL,
1048         },
1049 };
1050
1051 static unsigned int rpcb_version2_counts[ARRAY_SIZE(rpcb_procedures2)];
1052 static const struct rpc_version rpcb_version2 = {
1053         .number         = RPCBVERS_2,
1054         .nrprocs        = ARRAY_SIZE(rpcb_procedures2),
1055         .procs          = rpcb_procedures2,
1056         .counts         = rpcb_version2_counts,
1057 };
1058
1059 static unsigned int rpcb_version3_counts[ARRAY_SIZE(rpcb_procedures3)];
1060 static const struct rpc_version rpcb_version3 = {
1061         .number         = RPCBVERS_3,
1062         .nrprocs        = ARRAY_SIZE(rpcb_procedures3),
1063         .procs          = rpcb_procedures3,
1064         .counts         = rpcb_version3_counts,
1065 };
1066
1067 static unsigned int rpcb_version4_counts[ARRAY_SIZE(rpcb_procedures4)];
1068 static const struct rpc_version rpcb_version4 = {
1069         .number         = RPCBVERS_4,
1070         .nrprocs        = ARRAY_SIZE(rpcb_procedures4),
1071         .procs          = rpcb_procedures4,
1072         .counts         = rpcb_version4_counts,
1073 };
1074
1075 static const struct rpc_version *rpcb_version[] = {
1076         NULL,
1077         NULL,
1078         &rpcb_version2,
1079         &rpcb_version3,
1080         &rpcb_version4
1081 };
1082
1083 static struct rpc_stat rpcb_stats;
1084
1085 static const struct rpc_program rpcb_program = {
1086         .name           = "rpcbind",
1087         .number         = RPCBIND_PROGRAM,
1088         .nrvers         = ARRAY_SIZE(rpcb_version),
1089         .version        = rpcb_version,
1090         .stats          = &rpcb_stats,
1091 };