linux/net/sunrpc/rpcb_clnt.c
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   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
  47enum {
  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
 112static void                     rpcb_getport_done(struct rpc_task *, void *);
 113static void                     rpcb_map_release(void *data);
 114static const struct rpc_program rpcb_program;
 115
 116struct 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
 130static const struct rpc_procinfo rpcb_procedures2[];
 131static const struct rpc_procinfo rpcb_procedures3[];
 132static const struct rpc_procinfo rpcb_procedures4[];
 133
 134struct rpcb_info {
 135        u32                     rpc_vers;
 136        const struct rpc_procinfo *rpc_proc;
 137};
 138
 139static const struct rpcb_info rpcb_next_version[];
 140static const struct rpcb_info rpcb_next_version6[];
 141
 142static const struct rpc_call_ops rpcb_getport_ops = {
 143        .rpc_call_done          = rpcb_getport_done,
 144        .rpc_release            = rpcb_map_release,
 145};
 146
 147static 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
 153static 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
 163static 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
 177void 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
 205static 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 */
 223static 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
 268out:
 269        return result;
 270}
 271
 272/*
 273 * Returns zero on success, otherwise a negative errno value
 274 * is returned.
 275 */
 276static 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
 315out:
 316        return result;
 317}
 318
 319/*
 320 * Returns zero on success, otherwise a negative errno value
 321 * is returned.
 322 */
 323int 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
 338out:
 339        mutex_unlock(&rpcb_create_local_mutex);
 340        return result;
 341}
 342
 343static 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                                    const struct rpc_timeout *timeo)
 349{
 350        struct rpc_create_args args = {
 351                .net            = net,
 352                .protocol       = proto,
 353                .address        = srvaddr,
 354                .addrsize       = salen,
 355                .timeout        = timeo,
 356                .servername     = hostname,
 357                .nodename       = nodename,
 358                .program        = &rpcb_program,
 359                .version        = version,
 360                .authflavor     = RPC_AUTH_UNIX,
 361                .cred           = cred,
 362                .flags          = (RPC_CLNT_CREATE_NOPING |
 363                                        RPC_CLNT_CREATE_NONPRIVPORT),
 364        };
 365
 366        switch (srvaddr->sa_family) {
 367        case AF_INET:
 368                ((struct sockaddr_in *)srvaddr)->sin_port = htons(RPCBIND_PORT);
 369                break;
 370        case AF_INET6:
 371                ((struct sockaddr_in6 *)srvaddr)->sin6_port = htons(RPCBIND_PORT);
 372                break;
 373        default:
 374                return ERR_PTR(-EAFNOSUPPORT);
 375        }
 376
 377        return rpc_create(&args);
 378}
 379
 380static int rpcb_register_call(struct sunrpc_net *sn, struct rpc_clnt *clnt, struct rpc_message *msg, bool is_set)
 381{
 382        int flags = RPC_TASK_NOCONNECT;
 383        int error, result = 0;
 384
 385        if (is_set || !sn->rpcb_is_af_local)
 386                flags = RPC_TASK_SOFTCONN;
 387        msg->rpc_resp = &result;
 388
 389        error = rpc_call_sync(clnt, msg, flags);
 390        if (error < 0)
 391                return error;
 392
 393        if (!result)
 394                return -EACCES;
 395        return 0;
 396}
 397
 398/**
 399 * rpcb_register - set or unset a port registration with the local rpcbind svc
 400 * @net: target network namespace
 401 * @prog: RPC program number to bind
 402 * @vers: RPC version number to bind
 403 * @prot: transport protocol to register
 404 * @port: port value to register
 405 *
 406 * Returns zero if the registration request was dispatched successfully
 407 * and the rpcbind daemon returned success.  Otherwise, returns an errno
 408 * value that reflects the nature of the error (request could not be
 409 * dispatched, timed out, or rpcbind returned an error).
 410 *
 411 * RPC services invoke this function to advertise their contact
 412 * information via the system's rpcbind daemon.  RPC services
 413 * invoke this function once for each [program, version, transport]
 414 * tuple they wish to advertise.
 415 *
 416 * Callers may also unregister RPC services that are no longer
 417 * available by setting the passed-in port to zero.  This removes
 418 * all registered transports for [program, version] from the local
 419 * rpcbind database.
 420 *
 421 * This function uses rpcbind protocol version 2 to contact the
 422 * local rpcbind daemon.
 423 *
 424 * Registration works over both AF_INET and AF_INET6, and services
 425 * registered via this function are advertised as available for any
 426 * address.  If the local rpcbind daemon is listening on AF_INET6,
 427 * services registered via this function will be advertised on
 428 * IN6ADDR_ANY (ie available for all AF_INET and AF_INET6
 429 * addresses).
 430 */
 431int rpcb_register(struct net *net, u32 prog, u32 vers, int prot, unsigned short port)
 432{
 433        struct rpcbind_args map = {
 434                .r_prog         = prog,
 435                .r_vers         = vers,
 436                .r_prot         = prot,
 437                .r_port         = port,
 438        };
 439        struct rpc_message msg = {
 440                .rpc_argp       = &map,
 441        };
 442        struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 443        bool is_set = false;
 444
 445        trace_pmap_register(prog, vers, prot, port);
 446
 447        msg.rpc_proc = &rpcb_procedures2[RPCBPROC_UNSET];
 448        if (port != 0) {
 449                msg.rpc_proc = &rpcb_procedures2[RPCBPROC_SET];
 450                is_set = true;
 451        }
 452
 453        return rpcb_register_call(sn, sn->rpcb_local_clnt, &msg, is_set);
 454}
 455
 456/*
 457 * Fill in AF_INET family-specific arguments to register
 458 */
 459static int rpcb_register_inet4(struct sunrpc_net *sn,
 460                               const struct sockaddr *sap,
 461                               struct rpc_message *msg)
 462{
 463        const struct sockaddr_in *sin = (const struct sockaddr_in *)sap;
 464        struct rpcbind_args *map = msg->rpc_argp;
 465        unsigned short port = ntohs(sin->sin_port);
 466        bool is_set = false;
 467        int result;
 468
 469        map->r_addr = rpc_sockaddr2uaddr(sap, GFP_KERNEL);
 470
 471        msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
 472        if (port != 0) {
 473                msg->rpc_proc = &rpcb_procedures4[RPCBPROC_SET];
 474                is_set = true;
 475        }
 476
 477        result = rpcb_register_call(sn, sn->rpcb_local_clnt4, msg, is_set);
 478        kfree(map->r_addr);
 479        return result;
 480}
 481
 482/*
 483 * Fill in AF_INET6 family-specific arguments to register
 484 */
 485static int rpcb_register_inet6(struct sunrpc_net *sn,
 486                               const struct sockaddr *sap,
 487                               struct rpc_message *msg)
 488{
 489        const struct sockaddr_in6 *sin6 = (const struct sockaddr_in6 *)sap;
 490        struct rpcbind_args *map = msg->rpc_argp;
 491        unsigned short port = ntohs(sin6->sin6_port);
 492        bool is_set = false;
 493        int result;
 494
 495        map->r_addr = rpc_sockaddr2uaddr(sap, GFP_KERNEL);
 496
 497        msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
 498        if (port != 0) {
 499                msg->rpc_proc = &rpcb_procedures4[RPCBPROC_SET];
 500                is_set = true;
 501        }
 502
 503        result = rpcb_register_call(sn, sn->rpcb_local_clnt4, msg, is_set);
 504        kfree(map->r_addr);
 505        return result;
 506}
 507
 508static int rpcb_unregister_all_protofamilies(struct sunrpc_net *sn,
 509                                             struct rpc_message *msg)
 510{
 511        struct rpcbind_args *map = msg->rpc_argp;
 512
 513        trace_rpcb_unregister(map->r_prog, map->r_vers, map->r_netid);
 514
 515        map->r_addr = "";
 516        msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
 517
 518        return rpcb_register_call(sn, sn->rpcb_local_clnt4, msg, false);
 519}
 520
 521/**
 522 * rpcb_v4_register - set or unset a port registration with the local rpcbind
 523 * @net: target network namespace
 524 * @program: RPC program number of service to (un)register
 525 * @version: RPC version number of service to (un)register
 526 * @address: address family, IP address, and port to (un)register
 527 * @netid: netid of transport protocol to (un)register
 528 *
 529 * Returns zero if the registration request was dispatched successfully
 530 * and the rpcbind daemon returned success.  Otherwise, returns an errno
 531 * value that reflects the nature of the error (request could not be
 532 * dispatched, timed out, or rpcbind returned an error).
 533 *
 534 * RPC services invoke this function to advertise their contact
 535 * information via the system's rpcbind daemon.  RPC services
 536 * invoke this function once for each [program, version, address,
 537 * netid] tuple they wish to advertise.
 538 *
 539 * Callers may also unregister RPC services that are registered at a
 540 * specific address by setting the port number in @address to zero.
 541 * They may unregister all registered protocol families at once for
 542 * a service by passing a NULL @address argument.  If @netid is ""
 543 * then all netids for [program, version, address] are unregistered.
 544 *
 545 * This function uses rpcbind protocol version 4 to contact the
 546 * local rpcbind daemon.  The local rpcbind daemon must support
 547 * version 4 of the rpcbind protocol in order for these functions
 548 * to register a service successfully.
 549 *
 550 * Supported netids include "udp" and "tcp" for UDP and TCP over
 551 * IPv4, and "udp6" and "tcp6" for UDP and TCP over IPv6,
 552 * respectively.
 553 *
 554 * The contents of @address determine the address family and the
 555 * port to be registered.  The usual practice is to pass INADDR_ANY
 556 * as the raw address, but specifying a non-zero address is also
 557 * supported by this API if the caller wishes to advertise an RPC
 558 * service on a specific network interface.
 559 *
 560 * Note that passing in INADDR_ANY does not create the same service
 561 * registration as IN6ADDR_ANY.  The former advertises an RPC
 562 * service on any IPv4 address, but not on IPv6.  The latter
 563 * advertises the service on all IPv4 and IPv6 addresses.
 564 */
 565int rpcb_v4_register(struct net *net, const u32 program, const u32 version,
 566                     const struct sockaddr *address, const char *netid)
 567{
 568        struct rpcbind_args map = {
 569                .r_prog         = program,
 570                .r_vers         = version,
 571                .r_netid        = netid,
 572                .r_owner        = RPCB_OWNER_STRING,
 573        };
 574        struct rpc_message msg = {
 575                .rpc_argp       = &map,
 576        };
 577        struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 578
 579        if (sn->rpcb_local_clnt4 == NULL)
 580                return -EPROTONOSUPPORT;
 581
 582        if (address == NULL)
 583                return rpcb_unregister_all_protofamilies(sn, &msg);
 584
 585        trace_rpcb_register(map.r_prog, map.r_vers, map.r_addr, map.r_netid);
 586
 587        switch (address->sa_family) {
 588        case AF_INET:
 589                return rpcb_register_inet4(sn, address, &msg);
 590        case AF_INET6:
 591                return rpcb_register_inet6(sn, address, &msg);
 592        }
 593
 594        return -EAFNOSUPPORT;
 595}
 596
 597static struct rpc_task *rpcb_call_async(struct rpc_clnt *rpcb_clnt,
 598                struct rpcbind_args *map, const struct rpc_procinfo *proc)
 599{
 600        struct rpc_message msg = {
 601                .rpc_proc = proc,
 602                .rpc_argp = map,
 603                .rpc_resp = map,
 604        };
 605        struct rpc_task_setup task_setup_data = {
 606                .rpc_client = rpcb_clnt,
 607                .rpc_message = &msg,
 608                .callback_ops = &rpcb_getport_ops,
 609                .callback_data = map,
 610                .flags = RPC_TASK_ASYNC | RPC_TASK_SOFTCONN,
 611        };
 612
 613        return rpc_run_task(&task_setup_data);
 614}
 615
 616/*
 617 * In the case where rpc clients have been cloned, we want to make
 618 * sure that we use the program number/version etc of the actual
 619 * owner of the xprt. To do so, we walk back up the tree of parents
 620 * to find whoever created the transport and/or whoever has the
 621 * autobind flag set.
 622 */
 623static struct rpc_clnt *rpcb_find_transport_owner(struct rpc_clnt *clnt)
 624{
 625        struct rpc_clnt *parent = clnt->cl_parent;
 626        struct rpc_xprt_switch *xps = rcu_access_pointer(clnt->cl_xpi.xpi_xpswitch);
 627
 628        while (parent != clnt) {
 629                if (rcu_access_pointer(parent->cl_xpi.xpi_xpswitch) != xps)
 630                        break;
 631                if (clnt->cl_autobind)
 632                        break;
 633                clnt = parent;
 634                parent = parent->cl_parent;
 635        }
 636        return clnt;
 637}
 638
 639/**
 640 * rpcb_getport_async - obtain the port for a given RPC service on a given host
 641 * @task: task that is waiting for portmapper request
 642 *
 643 * This one can be called for an ongoing RPC request, and can be used in
 644 * an async (rpciod) context.
 645 */
 646void rpcb_getport_async(struct rpc_task *task)
 647{
 648        struct rpc_clnt *clnt;
 649        const struct rpc_procinfo *proc;
 650        u32 bind_version;
 651        struct rpc_xprt *xprt;
 652        struct rpc_clnt *rpcb_clnt;
 653        struct rpcbind_args *map;
 654        struct rpc_task *child;
 655        struct sockaddr_storage addr;
 656        struct sockaddr *sap = (struct sockaddr *)&addr;
 657        size_t salen;
 658        int status;
 659
 660        rcu_read_lock();
 661        clnt = rpcb_find_transport_owner(task->tk_client);
 662        rcu_read_unlock();
 663        xprt = xprt_get(task->tk_xprt);
 664
 665        /* Put self on the wait queue to ensure we get notified if
 666         * some other task is already attempting to bind the port */
 667        rpc_sleep_on_timeout(&xprt->binding, task,
 668                        NULL, jiffies + xprt->bind_timeout);
 669
 670        if (xprt_test_and_set_binding(xprt)) {
 671                xprt_put(xprt);
 672                return;
 673        }
 674
 675        /* Someone else may have bound if we slept */
 676        if (xprt_bound(xprt)) {
 677                status = 0;
 678                goto bailout_nofree;
 679        }
 680
 681        /* Parent transport's destination address */
 682        salen = rpc_peeraddr(clnt, sap, sizeof(addr));
 683
 684        /* Don't ever use rpcbind v2 for AF_INET6 requests */
 685        switch (sap->sa_family) {
 686        case AF_INET:
 687                proc = rpcb_next_version[xprt->bind_index].rpc_proc;
 688                bind_version = rpcb_next_version[xprt->bind_index].rpc_vers;
 689                break;
 690        case AF_INET6:
 691                proc = rpcb_next_version6[xprt->bind_index].rpc_proc;
 692                bind_version = rpcb_next_version6[xprt->bind_index].rpc_vers;
 693                break;
 694        default:
 695                status = -EAFNOSUPPORT;
 696                goto bailout_nofree;
 697        }
 698        if (proc == NULL) {
 699                xprt->bind_index = 0;
 700                status = -EPFNOSUPPORT;
 701                goto bailout_nofree;
 702        }
 703
 704        trace_rpcb_getport(clnt, task, bind_version);
 705
 706        rpcb_clnt = rpcb_create(xprt->xprt_net,
 707                                clnt->cl_nodename,
 708                                xprt->servername, sap, salen,
 709                                xprt->prot, bind_version,
 710                                clnt->cl_cred,
 711                                task->tk_client->cl_timeout);
 712        if (IS_ERR(rpcb_clnt)) {
 713                status = PTR_ERR(rpcb_clnt);
 714                goto bailout_nofree;
 715        }
 716
 717        map = kzalloc(sizeof(struct rpcbind_args), GFP_NOFS);
 718        if (!map) {
 719                status = -ENOMEM;
 720                goto bailout_release_client;
 721        }
 722        map->r_prog = clnt->cl_prog;
 723        map->r_vers = clnt->cl_vers;
 724        map->r_prot = xprt->prot;
 725        map->r_port = 0;
 726        map->r_xprt = xprt;
 727        map->r_status = -EIO;
 728
 729        switch (bind_version) {
 730        case RPCBVERS_4:
 731        case RPCBVERS_3:
 732                map->r_netid = xprt->address_strings[RPC_DISPLAY_NETID];
 733                map->r_addr = rpc_sockaddr2uaddr(sap, GFP_NOFS);
 734                if (!map->r_addr) {
 735                        status = -ENOMEM;
 736                        goto bailout_free_args;
 737                }
 738                map->r_owner = "";
 739                break;
 740        case RPCBVERS_2:
 741                map->r_addr = NULL;
 742                break;
 743        default:
 744                BUG();
 745        }
 746
 747        child = rpcb_call_async(rpcb_clnt, map, proc);
 748        rpc_release_client(rpcb_clnt);
 749
 750        xprt->stat.bind_count++;
 751        rpc_put_task(child);
 752        return;
 753
 754bailout_free_args:
 755        kfree(map);
 756bailout_release_client:
 757        rpc_release_client(rpcb_clnt);
 758bailout_nofree:
 759        rpcb_wake_rpcbind_waiters(xprt, status);
 760        task->tk_status = status;
 761        xprt_put(xprt);
 762}
 763EXPORT_SYMBOL_GPL(rpcb_getport_async);
 764
 765/*
 766 * Rpcbind child task calls this callback via tk_exit.
 767 */
 768static void rpcb_getport_done(struct rpc_task *child, void *data)
 769{
 770        struct rpcbind_args *map = data;
 771        struct rpc_xprt *xprt = map->r_xprt;
 772
 773        map->r_status = child->tk_status;
 774
 775        /* Garbage reply: retry with a lesser rpcbind version */
 776        if (map->r_status == -EIO)
 777                map->r_status = -EPROTONOSUPPORT;
 778
 779        /* rpcbind server doesn't support this rpcbind protocol version */
 780        if (map->r_status == -EPROTONOSUPPORT)
 781                xprt->bind_index++;
 782
 783        if (map->r_status < 0) {
 784                /* rpcbind server not available on remote host? */
 785                map->r_port = 0;
 786
 787        } else if (map->r_port == 0) {
 788                /* Requested RPC service wasn't registered on remote host */
 789                map->r_status = -EACCES;
 790        } else {
 791                /* Succeeded */
 792                map->r_status = 0;
 793        }
 794
 795        trace_rpcb_setport(child, map->r_status, map->r_port);
 796        xprt->ops->set_port(xprt, map->r_port);
 797        if (map->r_port)
 798                xprt_set_bound(xprt);
 799}
 800
 801/*
 802 * XDR functions for rpcbind
 803 */
 804
 805static void rpcb_enc_mapping(struct rpc_rqst *req, struct xdr_stream *xdr,
 806                             const void *data)
 807{
 808        const struct rpcbind_args *rpcb = data;
 809        __be32 *p;
 810
 811        p = xdr_reserve_space(xdr, RPCB_mappingargs_sz << 2);
 812        *p++ = cpu_to_be32(rpcb->r_prog);
 813        *p++ = cpu_to_be32(rpcb->r_vers);
 814        *p++ = cpu_to_be32(rpcb->r_prot);
 815        *p   = cpu_to_be32(rpcb->r_port);
 816}
 817
 818static int rpcb_dec_getport(struct rpc_rqst *req, struct xdr_stream *xdr,
 819                            void *data)
 820{
 821        struct rpcbind_args *rpcb = data;
 822        unsigned long port;
 823        __be32 *p;
 824
 825        rpcb->r_port = 0;
 826
 827        p = xdr_inline_decode(xdr, 4);
 828        if (unlikely(p == NULL))
 829                return -EIO;
 830
 831        port = be32_to_cpup(p);
 832        if (unlikely(port > USHRT_MAX))
 833                return -EIO;
 834
 835        rpcb->r_port = port;
 836        return 0;
 837}
 838
 839static int rpcb_dec_set(struct rpc_rqst *req, struct xdr_stream *xdr,
 840                        void *data)
 841{
 842        unsigned int *boolp = data;
 843        __be32 *p;
 844
 845        p = xdr_inline_decode(xdr, 4);
 846        if (unlikely(p == NULL))
 847                return -EIO;
 848
 849        *boolp = 0;
 850        if (*p != xdr_zero)
 851                *boolp = 1;
 852        return 0;
 853}
 854
 855static void encode_rpcb_string(struct xdr_stream *xdr, const char *string,
 856                               const u32 maxstrlen)
 857{
 858        __be32 *p;
 859        u32 len;
 860
 861        len = strlen(string);
 862        WARN_ON_ONCE(len > maxstrlen);
 863        if (len > maxstrlen)
 864                /* truncate and hope for the best */
 865                len = maxstrlen;
 866        p = xdr_reserve_space(xdr, 4 + len);
 867        xdr_encode_opaque(p, string, len);
 868}
 869
 870static void rpcb_enc_getaddr(struct rpc_rqst *req, struct xdr_stream *xdr,
 871                             const void *data)
 872{
 873        const struct rpcbind_args *rpcb = data;
 874        __be32 *p;
 875
 876        p = xdr_reserve_space(xdr, (RPCB_program_sz + RPCB_version_sz) << 2);
 877        *p++ = cpu_to_be32(rpcb->r_prog);
 878        *p = cpu_to_be32(rpcb->r_vers);
 879
 880        encode_rpcb_string(xdr, rpcb->r_netid, RPCBIND_MAXNETIDLEN);
 881        encode_rpcb_string(xdr, rpcb->r_addr, RPCBIND_MAXUADDRLEN);
 882        encode_rpcb_string(xdr, rpcb->r_owner, RPCB_MAXOWNERLEN);
 883}
 884
 885static int rpcb_dec_getaddr(struct rpc_rqst *req, struct xdr_stream *xdr,
 886                            void *data)
 887{
 888        struct rpcbind_args *rpcb = data;
 889        struct sockaddr_storage address;
 890        struct sockaddr *sap = (struct sockaddr *)&address;
 891        __be32 *p;
 892        u32 len;
 893
 894        rpcb->r_port = 0;
 895
 896        p = xdr_inline_decode(xdr, 4);
 897        if (unlikely(p == NULL))
 898                goto out_fail;
 899        len = be32_to_cpup(p);
 900
 901        /*
 902         * If the returned universal address is a null string,
 903         * the requested RPC service was not registered.
 904         */
 905        if (len == 0)
 906                return 0;
 907
 908        if (unlikely(len > RPCBIND_MAXUADDRLEN))
 909                goto out_fail;
 910
 911        p = xdr_inline_decode(xdr, len);
 912        if (unlikely(p == NULL))
 913                goto out_fail;
 914
 915        if (rpc_uaddr2sockaddr(req->rq_xprt->xprt_net, (char *)p, len,
 916                                sap, sizeof(address)) == 0)
 917                goto out_fail;
 918        rpcb->r_port = rpc_get_port(sap);
 919
 920        return 0;
 921
 922out_fail:
 923        return -EIO;
 924}
 925
 926/*
 927 * Not all rpcbind procedures described in RFC 1833 are implemented
 928 * since the Linux kernel RPC code requires only these.
 929 */
 930
 931static const struct rpc_procinfo rpcb_procedures2[] = {
 932        [RPCBPROC_SET] = {
 933                .p_proc         = RPCBPROC_SET,
 934                .p_encode       = rpcb_enc_mapping,
 935                .p_decode       = rpcb_dec_set,
 936                .p_arglen       = RPCB_mappingargs_sz,
 937                .p_replen       = RPCB_setres_sz,
 938                .p_statidx      = RPCBPROC_SET,
 939                .p_timer        = 0,
 940                .p_name         = "SET",
 941        },
 942        [RPCBPROC_UNSET] = {
 943                .p_proc         = RPCBPROC_UNSET,
 944                .p_encode       = rpcb_enc_mapping,
 945                .p_decode       = rpcb_dec_set,
 946                .p_arglen       = RPCB_mappingargs_sz,
 947                .p_replen       = RPCB_setres_sz,
 948                .p_statidx      = RPCBPROC_UNSET,
 949                .p_timer        = 0,
 950                .p_name         = "UNSET",
 951        },
 952        [RPCBPROC_GETPORT] = {
 953                .p_proc         = RPCBPROC_GETPORT,
 954                .p_encode       = rpcb_enc_mapping,
 955                .p_decode       = rpcb_dec_getport,
 956                .p_arglen       = RPCB_mappingargs_sz,
 957                .p_replen       = RPCB_getportres_sz,
 958                .p_statidx      = RPCBPROC_GETPORT,
 959                .p_timer        = 0,
 960                .p_name         = "GETPORT",
 961        },
 962};
 963
 964static const struct rpc_procinfo rpcb_procedures3[] = {
 965        [RPCBPROC_SET] = {
 966                .p_proc         = RPCBPROC_SET,
 967                .p_encode       = rpcb_enc_getaddr,
 968                .p_decode       = rpcb_dec_set,
 969                .p_arglen       = RPCB_getaddrargs_sz,
 970                .p_replen       = RPCB_setres_sz,
 971                .p_statidx      = RPCBPROC_SET,
 972                .p_timer        = 0,
 973                .p_name         = "SET",
 974        },
 975        [RPCBPROC_UNSET] = {
 976                .p_proc         = RPCBPROC_UNSET,
 977                .p_encode       = rpcb_enc_getaddr,
 978                .p_decode       = rpcb_dec_set,
 979                .p_arglen       = RPCB_getaddrargs_sz,
 980                .p_replen       = RPCB_setres_sz,
 981                .p_statidx      = RPCBPROC_UNSET,
 982                .p_timer        = 0,
 983                .p_name         = "UNSET",
 984        },
 985        [RPCBPROC_GETADDR] = {
 986                .p_proc         = RPCBPROC_GETADDR,
 987                .p_encode       = rpcb_enc_getaddr,
 988                .p_decode       = rpcb_dec_getaddr,
 989                .p_arglen       = RPCB_getaddrargs_sz,
 990                .p_replen       = RPCB_getaddrres_sz,
 991                .p_statidx      = RPCBPROC_GETADDR,
 992                .p_timer        = 0,
 993                .p_name         = "GETADDR",
 994        },
 995};
 996
 997static const struct rpc_procinfo rpcb_procedures4[] = {
 998        [RPCBPROC_SET] = {
 999                .p_proc         = RPCBPROC_SET,
1000                .p_encode       = rpcb_enc_getaddr,
1001                .p_decode       = rpcb_dec_set,
1002                .p_arglen       = RPCB_getaddrargs_sz,
1003                .p_replen       = RPCB_setres_sz,
1004                .p_statidx      = RPCBPROC_SET,
1005                .p_timer        = 0,
1006                .p_name         = "SET",
1007        },
1008        [RPCBPROC_UNSET] = {
1009                .p_proc         = RPCBPROC_UNSET,
1010                .p_encode       = rpcb_enc_getaddr,
1011                .p_decode       = rpcb_dec_set,
1012                .p_arglen       = RPCB_getaddrargs_sz,
1013                .p_replen       = RPCB_setres_sz,
1014                .p_statidx      = RPCBPROC_UNSET,
1015                .p_timer        = 0,
1016                .p_name         = "UNSET",
1017        },
1018        [RPCBPROC_GETADDR] = {
1019                .p_proc         = RPCBPROC_GETADDR,
1020                .p_encode       = rpcb_enc_getaddr,
1021                .p_decode       = rpcb_dec_getaddr,
1022                .p_arglen       = RPCB_getaddrargs_sz,
1023                .p_replen       = RPCB_getaddrres_sz,
1024                .p_statidx      = RPCBPROC_GETADDR,
1025                .p_timer        = 0,
1026                .p_name         = "GETADDR",
1027        },
1028};
1029
1030static const struct rpcb_info rpcb_next_version[] = {
1031        {
1032                .rpc_vers       = RPCBVERS_2,
1033                .rpc_proc       = &rpcb_procedures2[RPCBPROC_GETPORT],
1034        },
1035        {
1036                .rpc_proc       = NULL,
1037        },
1038};
1039
1040static const struct rpcb_info rpcb_next_version6[] = {
1041        {
1042                .rpc_vers       = RPCBVERS_4,
1043                .rpc_proc       = &rpcb_procedures4[RPCBPROC_GETADDR],
1044        },
1045        {
1046                .rpc_vers       = RPCBVERS_3,
1047                .rpc_proc       = &rpcb_procedures3[RPCBPROC_GETADDR],
1048        },
1049        {
1050                .rpc_proc       = NULL,
1051        },
1052};
1053
1054static unsigned int rpcb_version2_counts[ARRAY_SIZE(rpcb_procedures2)];
1055static const struct rpc_version rpcb_version2 = {
1056        .number         = RPCBVERS_2,
1057        .nrprocs        = ARRAY_SIZE(rpcb_procedures2),
1058        .procs          = rpcb_procedures2,
1059        .counts         = rpcb_version2_counts,
1060};
1061
1062static unsigned int rpcb_version3_counts[ARRAY_SIZE(rpcb_procedures3)];
1063static const struct rpc_version rpcb_version3 = {
1064        .number         = RPCBVERS_3,
1065        .nrprocs        = ARRAY_SIZE(rpcb_procedures3),
1066        .procs          = rpcb_procedures3,
1067        .counts         = rpcb_version3_counts,
1068};
1069
1070static unsigned int rpcb_version4_counts[ARRAY_SIZE(rpcb_procedures4)];
1071static const struct rpc_version rpcb_version4 = {
1072        .number         = RPCBVERS_4,
1073        .nrprocs        = ARRAY_SIZE(rpcb_procedures4),
1074        .procs          = rpcb_procedures4,
1075        .counts         = rpcb_version4_counts,
1076};
1077
1078static const struct rpc_version *rpcb_version[] = {
1079        NULL,
1080        NULL,
1081        &rpcb_version2,
1082        &rpcb_version3,
1083        &rpcb_version4
1084};
1085
1086static struct rpc_stat rpcb_stats;
1087
1088static const struct rpc_program rpcb_program = {
1089        .name           = "rpcbind",
1090        .number         = RPCBIND_PROGRAM,
1091        .nrvers         = ARRAY_SIZE(rpcb_version),
1092        .version        = rpcb_version,
1093        .stats          = &rpcb_stats,
1094};
1095