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#define RPCBIND_SOCK_ABSTRACT_NAME "\0/run/rpcbind.sock"
  40
  41#define RPCBIND_PROGRAM		(100000u)
  42#define RPCBIND_PORT		(111u)
  43
  44#define RPCBVERS_2		(2u)
  45#define RPCBVERS_3		(3u)
  46#define RPCBVERS_4		(4u)
  47
  48enum {
  49	RPCBPROC_NULL,
  50	RPCBPROC_SET,
  51	RPCBPROC_UNSET,
  52	RPCBPROC_GETPORT,
  53	RPCBPROC_GETADDR = 3,		/* alias for GETPORT */
  54	RPCBPROC_DUMP,
  55	RPCBPROC_CALLIT,
  56	RPCBPROC_BCAST = 5,		/* alias for CALLIT */
  57	RPCBPROC_GETTIME,
  58	RPCBPROC_UADDR2TADDR,
  59	RPCBPROC_TADDR2UADDR,
  60	RPCBPROC_GETVERSADDR,
  61	RPCBPROC_INDIRECT,
  62	RPCBPROC_GETADDRLIST,
  63	RPCBPROC_GETSTAT,
  64};
  65
  66/*
  67 * r_owner
  68 *
  69 * The "owner" is allowed to unset a service in the rpcbind database.
  70 *
  71 * For AF_LOCAL SET/UNSET requests, rpcbind treats this string as a
  72 * UID which it maps to a local user name via a password lookup.
  73 * In all other cases it is ignored.
  74 *
  75 * For SET/UNSET requests, user space provides a value, even for
  76 * network requests, and GETADDR uses an empty string.  We follow
  77 * those precedents here.
  78 */
  79#define RPCB_OWNER_STRING	"0"
  80#define RPCB_MAXOWNERLEN	sizeof(RPCB_OWNER_STRING)
  81
  82/*
  83 * XDR data type sizes
  84 */
  85#define RPCB_program_sz		(1)
  86#define RPCB_version_sz		(1)
  87#define RPCB_protocol_sz	(1)
  88#define RPCB_port_sz		(1)
  89#define RPCB_boolean_sz		(1)
  90
  91#define RPCB_netid_sz		(1 + XDR_QUADLEN(RPCBIND_MAXNETIDLEN))
  92#define RPCB_addr_sz		(1 + XDR_QUADLEN(RPCBIND_MAXUADDRLEN))
  93#define RPCB_ownerstring_sz	(1 + XDR_QUADLEN(RPCB_MAXOWNERLEN))
  94
  95/*
  96 * XDR argument and result sizes
  97 */
  98#define RPCB_mappingargs_sz	(RPCB_program_sz + RPCB_version_sz + \
  99				RPCB_protocol_sz + RPCB_port_sz)
 100#define RPCB_getaddrargs_sz	(RPCB_program_sz + RPCB_version_sz + \
 101				RPCB_netid_sz + RPCB_addr_sz + \
 102				RPCB_ownerstring_sz)
 103
 104#define RPCB_getportres_sz	RPCB_port_sz
 105#define RPCB_setres_sz		RPCB_boolean_sz
 106
 107/*
 108 * Note that RFC 1833 does not put any size restrictions on the
 109 * address string returned by the remote rpcbind database.
 110 */
 111#define RPCB_getaddrres_sz	RPCB_addr_sz
 112
 113static void			rpcb_getport_done(struct rpc_task *, void *);
 114static void			rpcb_map_release(void *data);
 115static const struct rpc_program	rpcb_program;
 116
 117struct rpcbind_args {
 118	struct rpc_xprt *	r_xprt;
 119
 120	u32			r_prog;
 121	u32			r_vers;
 122	u32			r_prot;
 123	unsigned short		r_port;
 124	const char *		r_netid;
 125	const char *		r_addr;
 126	const char *		r_owner;
 127
 128	int			r_status;
 129};
 130
 131static const struct rpc_procinfo rpcb_procedures2[];
 132static const struct rpc_procinfo rpcb_procedures3[];
 133static const struct rpc_procinfo rpcb_procedures4[];
 134
 135struct rpcb_info {
 136	u32			rpc_vers;
 137	const struct rpc_procinfo *rpc_proc;
 138};
 139
 140static const struct rpcb_info rpcb_next_version[];
 141static const struct rpcb_info rpcb_next_version6[];
 142
 143static const struct rpc_call_ops rpcb_getport_ops = {
 144	.rpc_call_done		= rpcb_getport_done,
 145	.rpc_release		= rpcb_map_release,
 146};
 147
 148static void rpcb_wake_rpcbind_waiters(struct rpc_xprt *xprt, int status)
 149{
 150	xprt_clear_binding(xprt);
 151	rpc_wake_up_status(&xprt->binding, status);
 152}
 153
 154static void rpcb_map_release(void *data)
 155{
 156	struct rpcbind_args *map = data;
 157
 158	rpcb_wake_rpcbind_waiters(map->r_xprt, map->r_status);
 159	xprt_put(map->r_xprt);
 160	kfree(map->r_addr);
 161	kfree(map);
 162}
 163
 164static int rpcb_get_local(struct net *net)
 165{
 166	int cnt;
 167	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 168
 169	spin_lock(&sn->rpcb_clnt_lock);
 170	if (sn->rpcb_users)
 171		sn->rpcb_users++;
 172	cnt = sn->rpcb_users;
 173	spin_unlock(&sn->rpcb_clnt_lock);
 174
 175	return cnt;
 176}
 177
 178void rpcb_put_local(struct net *net)
 179{
 180	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 181	struct rpc_clnt *clnt = sn->rpcb_local_clnt;
 182	struct rpc_clnt *clnt4 = sn->rpcb_local_clnt4;
 183	int shutdown = 0;
 184
 185	spin_lock(&sn->rpcb_clnt_lock);
 186	if (sn->rpcb_users) {
 187		if (--sn->rpcb_users == 0) {
 188			sn->rpcb_local_clnt = NULL;
 189			sn->rpcb_local_clnt4 = NULL;
 190		}
 191		shutdown = !sn->rpcb_users;
 192	}
 193	spin_unlock(&sn->rpcb_clnt_lock);
 194
 195	if (shutdown) {
 196		/*
 197		 * cleanup_rpcb_clnt - remove xprtsock's sysctls, unregister
 198		 */
 199		if (clnt4)
 200			rpc_shutdown_client(clnt4);
 201		if (clnt)
 202			rpc_shutdown_client(clnt);
 203	}
 204}
 205
 206static void rpcb_set_local(struct net *net, struct rpc_clnt *clnt,
 207			struct rpc_clnt *clnt4,
 208			bool is_af_local)
 209{
 210	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 211
 212	/* Protected by rpcb_create_local_mutex */
 213	sn->rpcb_local_clnt = clnt;
 214	sn->rpcb_local_clnt4 = clnt4;
 215	sn->rpcb_is_af_local = is_af_local ? 1 : 0;
 216	smp_wmb();
 217	sn->rpcb_users = 1;
 218}
 219
 220/* Evaluate to actual length of the `sockaddr_un' structure.  */
 221# define SUN_LEN(ptr) (offsetof(struct sockaddr_un, sun_path)		\
 222		      + 1 + strlen((ptr)->sun_path + 1))
 223
 224/*
 225 * Returns zero on success, otherwise a negative errno value
 226 * is returned.
 227 */
 228static int rpcb_create_af_local(struct net *net,
 229				const struct sockaddr_un *addr)
 230{
 231	struct rpc_create_args args = {
 232		.net		= net,
 233		.protocol	= XPRT_TRANSPORT_LOCAL,
 234		.address	= (struct sockaddr *)addr,
 235		.addrsize	= SUN_LEN(addr),
 236		.servername	= "localhost",
 237		.program	= &rpcb_program,
 238		.version	= RPCBVERS_2,
 239		.authflavor	= RPC_AUTH_NULL,
 240		.cred		= current_cred(),
 241		/*
 242		 * We turn off the idle timeout to prevent the kernel
 243		 * from automatically disconnecting the socket.
 244		 * Otherwise, we'd have to cache the mount namespace
 245		 * of the caller and somehow pass that to the socket
 246		 * reconnect code.
 247		 */
 248		.flags		= RPC_CLNT_CREATE_NO_IDLE_TIMEOUT,
 249	};
 250	struct rpc_clnt *clnt, *clnt4;
 251	int result = 0;
 252
 253	/*
 254	 * Because we requested an RPC PING at transport creation time,
 255	 * this works only if the user space portmapper is rpcbind, and
 256	 * it's listening on AF_LOCAL on the named socket.
 257	 */
 258	clnt = rpc_create(&args);
 259	if (IS_ERR(clnt)) {
 260		result = PTR_ERR(clnt);
 261		goto out;
 262	}
 263
 264	clnt4 = rpc_bind_new_program(clnt, &rpcb_program, RPCBVERS_4);
 265	if (IS_ERR(clnt4))
 266		clnt4 = NULL;
 267
 268	rpcb_set_local(net, clnt, clnt4, true);
 269
 270out:
 271	return result;
 272}
 273
 274static int rpcb_create_local_abstract(struct net *net)
 275{
 276	static const struct sockaddr_un rpcb_localaddr_abstract = {
 277		.sun_family		= AF_LOCAL,
 278		.sun_path		= RPCBIND_SOCK_ABSTRACT_NAME,
 279	};
 280
 281	return rpcb_create_af_local(net, &rpcb_localaddr_abstract);
 282}
 283
 284static int rpcb_create_local_unix(struct net *net)
 285{
 286	static const struct sockaddr_un rpcb_localaddr_unix = {
 287		.sun_family		= AF_LOCAL,
 288		.sun_path		= RPCBIND_SOCK_PATHNAME,
 289	};
 290
 291	return rpcb_create_af_local(net, &rpcb_localaddr_unix);
 292}
 293
 294/*
 295 * Returns zero on success, otherwise a negative errno value
 296 * is returned.
 297 */
 298static int rpcb_create_local_net(struct net *net)
 299{
 300	static const struct sockaddr_in rpcb_inaddr_loopback = {
 301		.sin_family		= AF_INET,
 302		.sin_addr.s_addr	= htonl(INADDR_LOOPBACK),
 303		.sin_port		= htons(RPCBIND_PORT),
 304	};
 305	struct rpc_create_args args = {
 306		.net		= net,
 307		.protocol	= XPRT_TRANSPORT_TCP,
 308		.address	= (struct sockaddr *)&rpcb_inaddr_loopback,
 309		.addrsize	= sizeof(rpcb_inaddr_loopback),
 310		.servername	= "localhost",
 311		.program	= &rpcb_program,
 312		.version	= RPCBVERS_2,
 313		.authflavor	= RPC_AUTH_UNIX,
 314		.cred		= current_cred(),
 315		.flags		= RPC_CLNT_CREATE_NOPING,
 316	};
 317	struct rpc_clnt *clnt, *clnt4;
 318	int result = 0;
 319
 320	clnt = rpc_create(&args);
 321	if (IS_ERR(clnt)) {
 322		result = PTR_ERR(clnt);
 323		goto out;
 324	}
 325
 326	/*
 327	 * This results in an RPC ping.  On systems running portmapper,
 328	 * the v4 ping will fail.  Proceed anyway, but disallow rpcb
 329	 * v4 upcalls.
 330	 */
 331	clnt4 = rpc_bind_new_program(clnt, &rpcb_program, RPCBVERS_4);
 332	if (IS_ERR(clnt4))
 333		clnt4 = NULL;
 334
 335	rpcb_set_local(net, clnt, clnt4, false);
 336
 337out:
 338	return result;
 339}
 340
 341/*
 342 * Returns zero on success, otherwise a negative errno value
 343 * is returned.
 344 */
 345int rpcb_create_local(struct net *net)
 346{
 347	static DEFINE_MUTEX(rpcb_create_local_mutex);
 348	int result = 0;
 349
 350	if (rpcb_get_local(net))
 351		return result;
 352
 353	mutex_lock(&rpcb_create_local_mutex);
 354	if (rpcb_get_local(net))
 355		goto out;
 356
 357	if (rpcb_create_local_abstract(net) != 0 &&
 358	    rpcb_create_local_unix(net) != 0)
 359		result = rpcb_create_local_net(net);
 360
 361out:
 362	mutex_unlock(&rpcb_create_local_mutex);
 363	return result;
 364}
 365
 366static struct rpc_clnt *rpcb_create(struct net *net, const char *nodename,
 367				    const char *hostname,
 368				    struct sockaddr *srvaddr, size_t salen,
 369				    int proto, u32 version,
 370				    const struct cred *cred,
 371				    const struct rpc_timeout *timeo)
 372{
 373	struct rpc_create_args args = {
 374		.net		= net,
 375		.protocol	= proto,
 376		.address	= srvaddr,
 377		.addrsize	= salen,
 378		.timeout	= timeo,
 379		.servername	= hostname,
 380		.nodename	= nodename,
 381		.program	= &rpcb_program,
 382		.version	= version,
 383		.authflavor	= RPC_AUTH_UNIX,
 384		.cred		= cred,
 385		.flags		= (RPC_CLNT_CREATE_NOPING |
 386					RPC_CLNT_CREATE_NONPRIVPORT),
 387	};
 388
 389	switch (srvaddr->sa_family) {
 390	case AF_INET:
 391		((struct sockaddr_in *)srvaddr)->sin_port = htons(RPCBIND_PORT);
 392		break;
 393	case AF_INET6:
 394		((struct sockaddr_in6 *)srvaddr)->sin6_port = htons(RPCBIND_PORT);
 395		break;
 396	default:
 397		return ERR_PTR(-EAFNOSUPPORT);
 398	}
 399
 400	return rpc_create(&args);
 401}
 402
 403static int rpcb_register_call(struct sunrpc_net *sn, struct rpc_clnt *clnt, struct rpc_message *msg, bool is_set)
 404{
 405	int flags = RPC_TASK_NOCONNECT;
 406	int error, result = 0;
 407
 408	if (is_set || !sn->rpcb_is_af_local)
 409		flags = RPC_TASK_SOFTCONN;
 410	msg->rpc_resp = &result;
 411
 412	error = rpc_call_sync(clnt, msg, flags);
 413	if (error < 0)
 414		return error;
 415
 416	if (!result)
 417		return -EACCES;
 418	return 0;
 419}
 420
 421/**
 422 * rpcb_register - set or unset a port registration with the local rpcbind svc
 423 * @net: target network namespace
 424 * @prog: RPC program number to bind
 425 * @vers: RPC version number to bind
 426 * @prot: transport protocol to register
 427 * @port: port value to register
 428 *
 429 * Returns zero if the registration request was dispatched successfully
 430 * and the rpcbind daemon returned success.  Otherwise, returns an errno
 431 * value that reflects the nature of the error (request could not be
 432 * dispatched, timed out, or rpcbind returned an error).
 433 *
 434 * RPC services invoke this function to advertise their contact
 435 * information via the system's rpcbind daemon.  RPC services
 436 * invoke this function once for each [program, version, transport]
 437 * tuple they wish to advertise.
 438 *
 439 * Callers may also unregister RPC services that are no longer
 440 * available by setting the passed-in port to zero.  This removes
 441 * all registered transports for [program, version] from the local
 442 * rpcbind database.
 443 *
 444 * This function uses rpcbind protocol version 2 to contact the
 445 * local rpcbind daemon.
 446 *
 447 * Registration works over both AF_INET and AF_INET6, and services
 448 * registered via this function are advertised as available for any
 449 * address.  If the local rpcbind daemon is listening on AF_INET6,
 450 * services registered via this function will be advertised on
 451 * IN6ADDR_ANY (ie available for all AF_INET and AF_INET6
 452 * addresses).
 453 */
 454int rpcb_register(struct net *net, u32 prog, u32 vers, int prot, unsigned short port)
 455{
 456	struct rpcbind_args map = {
 457		.r_prog		= prog,
 458		.r_vers		= vers,
 459		.r_prot		= prot,
 460		.r_port		= port,
 461	};
 462	struct rpc_message msg = {
 463		.rpc_argp	= &map,
 464	};
 465	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 466	bool is_set = false;
 467
 468	trace_pmap_register(prog, vers, prot, port);
 469
 470	msg.rpc_proc = &rpcb_procedures2[RPCBPROC_UNSET];
 471	if (port != 0) {
 472		msg.rpc_proc = &rpcb_procedures2[RPCBPROC_SET];
 473		is_set = true;
 474	}
 475
 476	return rpcb_register_call(sn, sn->rpcb_local_clnt, &msg, is_set);
 477}
 478
 479/*
 480 * Fill in AF_INET family-specific arguments to register
 481 */
 482static int rpcb_register_inet4(struct sunrpc_net *sn,
 483			       const struct sockaddr *sap,
 484			       struct rpc_message *msg)
 485{
 486	const struct sockaddr_in *sin = (const struct sockaddr_in *)sap;
 487	struct rpcbind_args *map = msg->rpc_argp;
 488	unsigned short port = ntohs(sin->sin_port);
 489	bool is_set = false;
 490	int result;
 491
 492	map->r_addr = rpc_sockaddr2uaddr(sap, GFP_KERNEL);
 493
 494	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
 495	if (port != 0) {
 496		msg->rpc_proc = &rpcb_procedures4[RPCBPROC_SET];
 497		is_set = true;
 498	}
 499
 500	result = rpcb_register_call(sn, sn->rpcb_local_clnt4, msg, is_set);
 501	kfree(map->r_addr);
 502	return result;
 503}
 504
 505/*
 506 * Fill in AF_INET6 family-specific arguments to register
 507 */
 508static int rpcb_register_inet6(struct sunrpc_net *sn,
 509			       const struct sockaddr *sap,
 510			       struct rpc_message *msg)
 511{
 512	const struct sockaddr_in6 *sin6 = (const struct sockaddr_in6 *)sap;
 513	struct rpcbind_args *map = msg->rpc_argp;
 514	unsigned short port = ntohs(sin6->sin6_port);
 515	bool is_set = false;
 516	int result;
 517
 518	map->r_addr = rpc_sockaddr2uaddr(sap, GFP_KERNEL);
 519
 520	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
 521	if (port != 0) {
 522		msg->rpc_proc = &rpcb_procedures4[RPCBPROC_SET];
 523		is_set = true;
 524	}
 525
 526	result = rpcb_register_call(sn, sn->rpcb_local_clnt4, msg, is_set);
 527	kfree(map->r_addr);
 528	return result;
 529}
 530
 531static int rpcb_unregister_all_protofamilies(struct sunrpc_net *sn,
 532					     struct rpc_message *msg)
 533{
 534	struct rpcbind_args *map = msg->rpc_argp;
 535
 536	trace_rpcb_unregister(map->r_prog, map->r_vers, map->r_netid);
 537
 538	map->r_addr = "";
 539	msg->rpc_proc = &rpcb_procedures4[RPCBPROC_UNSET];
 540
 541	return rpcb_register_call(sn, sn->rpcb_local_clnt4, msg, false);
 542}
 543
 544/**
 545 * rpcb_v4_register - set or unset a port registration with the local rpcbind
 546 * @net: target network namespace
 547 * @program: RPC program number of service to (un)register
 548 * @version: RPC version number of service to (un)register
 549 * @address: address family, IP address, and port to (un)register
 550 * @netid: netid of transport protocol to (un)register
 551 *
 552 * Returns zero if the registration request was dispatched successfully
 553 * and the rpcbind daemon returned success.  Otherwise, returns an errno
 554 * value that reflects the nature of the error (request could not be
 555 * dispatched, timed out, or rpcbind returned an error).
 556 *
 557 * RPC services invoke this function to advertise their contact
 558 * information via the system's rpcbind daemon.  RPC services
 559 * invoke this function once for each [program, version, address,
 560 * netid] tuple they wish to advertise.
 561 *
 562 * Callers may also unregister RPC services that are registered at a
 563 * specific address by setting the port number in @address to zero.
 564 * They may unregister all registered protocol families at once for
 565 * a service by passing a NULL @address argument.  If @netid is ""
 566 * then all netids for [program, version, address] are unregistered.
 567 *
 568 * This function uses rpcbind protocol version 4 to contact the
 569 * local rpcbind daemon.  The local rpcbind daemon must support
 570 * version 4 of the rpcbind protocol in order for these functions
 571 * to register a service successfully.
 572 *
 573 * Supported netids include "udp" and "tcp" for UDP and TCP over
 574 * IPv4, and "udp6" and "tcp6" for UDP and TCP over IPv6,
 575 * respectively.
 576 *
 577 * The contents of @address determine the address family and the
 578 * port to be registered.  The usual practice is to pass INADDR_ANY
 579 * as the raw address, but specifying a non-zero address is also
 580 * supported by this API if the caller wishes to advertise an RPC
 581 * service on a specific network interface.
 582 *
 583 * Note that passing in INADDR_ANY does not create the same service
 584 * registration as IN6ADDR_ANY.  The former advertises an RPC
 585 * service on any IPv4 address, but not on IPv6.  The latter
 586 * advertises the service on all IPv4 and IPv6 addresses.
 587 */
 588int rpcb_v4_register(struct net *net, const u32 program, const u32 version,
 589		     const struct sockaddr *address, const char *netid)
 590{
 591	struct rpcbind_args map = {
 592		.r_prog		= program,
 593		.r_vers		= version,
 594		.r_netid	= netid,
 595		.r_owner	= RPCB_OWNER_STRING,
 596	};
 597	struct rpc_message msg = {
 598		.rpc_argp	= &map,
 599	};
 600	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 601
 602	if (sn->rpcb_local_clnt4 == NULL)
 603		return -EPROTONOSUPPORT;
 604
 605	if (address == NULL)
 606		return rpcb_unregister_all_protofamilies(sn, &msg);
 607
 608	trace_rpcb_register(map.r_prog, map.r_vers, map.r_addr, map.r_netid);
 609
 610	switch (address->sa_family) {
 611	case AF_INET:
 612		return rpcb_register_inet4(sn, address, &msg);
 613	case AF_INET6:
 614		return rpcb_register_inet6(sn, address, &msg);
 615	}
 616
 617	return -EAFNOSUPPORT;
 618}
 619
 620static struct rpc_task *rpcb_call_async(struct rpc_clnt *rpcb_clnt,
 621		struct rpcbind_args *map, const struct rpc_procinfo *proc)
 622{
 623	struct rpc_message msg = {
 624		.rpc_proc = proc,
 625		.rpc_argp = map,
 626		.rpc_resp = map,
 627	};
 628	struct rpc_task_setup task_setup_data = {
 629		.rpc_client = rpcb_clnt,
 630		.rpc_message = &msg,
 631		.callback_ops = &rpcb_getport_ops,
 632		.callback_data = map,
 633		.flags = RPC_TASK_ASYNC | RPC_TASK_SOFTCONN,
 634	};
 635
 636	return rpc_run_task(&task_setup_data);
 637}
 638
 639/*
 640 * In the case where rpc clients have been cloned, we want to make
 641 * sure that we use the program number/version etc of the actual
 642 * owner of the xprt. To do so, we walk back up the tree of parents
 643 * to find whoever created the transport and/or whoever has the
 644 * autobind flag set.
 645 */
 646static struct rpc_clnt *rpcb_find_transport_owner(struct rpc_clnt *clnt)
 647{
 648	struct rpc_clnt *parent = clnt->cl_parent;
 649	struct rpc_xprt_switch *xps = rcu_access_pointer(clnt->cl_xpi.xpi_xpswitch);
 650
 651	while (parent != clnt) {
 652		if (rcu_access_pointer(parent->cl_xpi.xpi_xpswitch) != xps)
 653			break;
 654		if (clnt->cl_autobind)
 655			break;
 656		clnt = parent;
 657		parent = parent->cl_parent;
 658	}
 659	return clnt;
 660}
 661
 662/**
 663 * rpcb_getport_async - obtain the port for a given RPC service on a given host
 664 * @task: task that is waiting for portmapper request
 665 *
 666 * This one can be called for an ongoing RPC request, and can be used in
 667 * an async (rpciod) context.
 668 */
 669void rpcb_getport_async(struct rpc_task *task)
 670{
 671	struct rpc_clnt *clnt;
 672	const struct rpc_procinfo *proc;
 673	u32 bind_version;
 674	struct rpc_xprt *xprt;
 675	struct rpc_clnt	*rpcb_clnt;
 676	struct rpcbind_args *map;
 677	struct rpc_task	*child;
 678	struct sockaddr_storage addr;
 679	struct sockaddr *sap = (struct sockaddr *)&addr;
 680	size_t salen;
 681	int status;
 682
 683	rcu_read_lock();
 684	clnt = rpcb_find_transport_owner(task->tk_client);
 685	rcu_read_unlock();
 686	xprt = xprt_get(task->tk_xprt);
 687
 688	/* Put self on the wait queue to ensure we get notified if
 689	 * some other task is already attempting to bind the port */
 690	rpc_sleep_on_timeout(&xprt->binding, task,
 691			NULL, jiffies + xprt->bind_timeout);
 692
 693	if (xprt_test_and_set_binding(xprt)) {
 694		xprt_put(xprt);
 695		return;
 696	}
 697
 698	/* Someone else may have bound if we slept */
 699	if (xprt_bound(xprt)) {
 700		status = 0;
 701		goto bailout_nofree;
 702	}
 703
 704	/* Parent transport's destination address */
 705	salen = rpc_peeraddr(clnt, sap, sizeof(addr));
 706
 707	/* Don't ever use rpcbind v2 for AF_INET6 requests */
 708	switch (sap->sa_family) {
 709	case AF_INET:
 710		proc = rpcb_next_version[xprt->bind_index].rpc_proc;
 711		bind_version = rpcb_next_version[xprt->bind_index].rpc_vers;
 712		break;
 713	case AF_INET6:
 714		proc = rpcb_next_version6[xprt->bind_index].rpc_proc;
 715		bind_version = rpcb_next_version6[xprt->bind_index].rpc_vers;
 716		break;
 717	default:
 718		status = -EAFNOSUPPORT;
 719		goto bailout_nofree;
 720	}
 721	if (proc == NULL) {
 722		xprt->bind_index = 0;
 723		status = -EPFNOSUPPORT;
 724		goto bailout_nofree;
 725	}
 726
 727	trace_rpcb_getport(clnt, task, bind_version);
 728
 729	rpcb_clnt = rpcb_create(xprt->xprt_net,
 730				clnt->cl_nodename,
 731				xprt->servername, sap, salen,
 732				xprt->prot, bind_version,
 733				clnt->cl_cred,
 734				task->tk_client->cl_timeout);
 735	if (IS_ERR(rpcb_clnt)) {
 736		status = PTR_ERR(rpcb_clnt);
 737		goto bailout_nofree;
 738	}
 739
 740	map = kzalloc(sizeof(struct rpcbind_args), rpc_task_gfp_mask());
 741	if (!map) {
 742		status = -ENOMEM;
 743		goto bailout_release_client;
 744	}
 745	map->r_prog = clnt->cl_prog;
 746	map->r_vers = clnt->cl_vers;
 747	map->r_prot = xprt->prot;
 748	map->r_port = 0;
 749	map->r_xprt = xprt;
 750	map->r_status = -EIO;
 751
 752	switch (bind_version) {
 753	case RPCBVERS_4:
 754	case RPCBVERS_3:
 755		map->r_netid = xprt->address_strings[RPC_DISPLAY_NETID];
 756		map->r_addr = rpc_sockaddr2uaddr(sap, rpc_task_gfp_mask());
 757		if (!map->r_addr) {
 758			status = -ENOMEM;
 759			goto bailout_free_args;
 760		}
 761		map->r_owner = "";
 762		break;
 763	case RPCBVERS_2:
 764		map->r_addr = NULL;
 765		break;
 766	default:
 767		BUG();
 768	}
 769
 770	child = rpcb_call_async(rpcb_clnt, map, proc);
 771	rpc_release_client(rpcb_clnt);
 772	if (IS_ERR(child)) {
 773		/* rpcb_map_release() has freed the arguments */
 774		return;
 775	}
 776
 777	xprt->stat.bind_count++;
 778	rpc_put_task(child);
 779	return;
 780
 781bailout_free_args:
 782	kfree(map);
 783bailout_release_client:
 784	rpc_release_client(rpcb_clnt);
 785bailout_nofree:
 786	rpcb_wake_rpcbind_waiters(xprt, status);
 787	task->tk_status = status;
 788	xprt_put(xprt);
 789}
 790EXPORT_SYMBOL_GPL(rpcb_getport_async);
 791
 792/*
 793 * Rpcbind child task calls this callback via tk_exit.
 794 */
 795static void rpcb_getport_done(struct rpc_task *child, void *data)
 796{
 797	struct rpcbind_args *map = data;
 798	struct rpc_xprt *xprt = map->r_xprt;
 799
 800	map->r_status = child->tk_status;
 801
 802	/* Garbage reply: retry with a lesser rpcbind version */
 803	if (map->r_status == -EIO)
 804		map->r_status = -EPROTONOSUPPORT;
 805
 806	/* rpcbind server doesn't support this rpcbind protocol version */
 807	if (map->r_status == -EPROTONOSUPPORT)
 808		xprt->bind_index++;
 809
 810	if (map->r_status < 0) {
 811		/* rpcbind server not available on remote host? */
 812		map->r_port = 0;
 813
 814	} else if (map->r_port == 0) {
 815		/* Requested RPC service wasn't registered on remote host */
 816		map->r_status = -EACCES;
 817	} else {
 818		/* Succeeded */
 819		map->r_status = 0;
 820	}
 821
 822	trace_rpcb_setport(child, map->r_status, map->r_port);
 823	xprt->ops->set_port(xprt, map->r_port);
 824	if (map->r_port)
 825		xprt_set_bound(xprt);
 826}
 827
 828/*
 829 * XDR functions for rpcbind
 830 */
 831
 832static void rpcb_enc_mapping(struct rpc_rqst *req, struct xdr_stream *xdr,
 833			     const void *data)
 834{
 835	const struct rpcbind_args *rpcb = data;
 836	__be32 *p;
 837
 838	p = xdr_reserve_space(xdr, RPCB_mappingargs_sz << 2);
 839	*p++ = cpu_to_be32(rpcb->r_prog);
 840	*p++ = cpu_to_be32(rpcb->r_vers);
 841	*p++ = cpu_to_be32(rpcb->r_prot);
 842	*p   = cpu_to_be32(rpcb->r_port);
 843}
 844
 845static int rpcb_dec_getport(struct rpc_rqst *req, struct xdr_stream *xdr,
 846			    void *data)
 847{
 848	struct rpcbind_args *rpcb = data;
 849	unsigned long port;
 850	__be32 *p;
 851
 852	rpcb->r_port = 0;
 853
 854	p = xdr_inline_decode(xdr, 4);
 855	if (unlikely(p == NULL))
 856		return -EIO;
 857
 858	port = be32_to_cpup(p);
 859	if (unlikely(port > USHRT_MAX))
 860		return -EIO;
 861
 862	rpcb->r_port = port;
 863	return 0;
 864}
 865
 866static int rpcb_dec_set(struct rpc_rqst *req, struct xdr_stream *xdr,
 867			void *data)
 868{
 869	unsigned int *boolp = data;
 870	__be32 *p;
 871
 872	p = xdr_inline_decode(xdr, 4);
 873	if (unlikely(p == NULL))
 874		return -EIO;
 875
 876	*boolp = 0;
 877	if (*p != xdr_zero)
 878		*boolp = 1;
 879	return 0;
 880}
 881
 882static void encode_rpcb_string(struct xdr_stream *xdr, const char *string,
 883			       const u32 maxstrlen)
 884{
 885	__be32 *p;
 886	u32 len;
 887
 888	len = strlen(string);
 889	WARN_ON_ONCE(len > maxstrlen);
 890	if (len > maxstrlen)
 891		/* truncate and hope for the best */
 892		len = maxstrlen;
 893	p = xdr_reserve_space(xdr, 4 + len);
 894	xdr_encode_opaque(p, string, len);
 895}
 896
 897static void rpcb_enc_getaddr(struct rpc_rqst *req, struct xdr_stream *xdr,
 898			     const void *data)
 899{
 900	const struct rpcbind_args *rpcb = data;
 901	__be32 *p;
 902
 903	p = xdr_reserve_space(xdr, (RPCB_program_sz + RPCB_version_sz) << 2);
 904	*p++ = cpu_to_be32(rpcb->r_prog);
 905	*p = cpu_to_be32(rpcb->r_vers);
 906
 907	encode_rpcb_string(xdr, rpcb->r_netid, RPCBIND_MAXNETIDLEN);
 908	encode_rpcb_string(xdr, rpcb->r_addr, RPCBIND_MAXUADDRLEN);
 909	encode_rpcb_string(xdr, rpcb->r_owner, RPCB_MAXOWNERLEN);
 910}
 911
 912static int rpcb_dec_getaddr(struct rpc_rqst *req, struct xdr_stream *xdr,
 913			    void *data)
 914{
 915	struct rpcbind_args *rpcb = data;
 916	struct sockaddr_storage address;
 917	struct sockaddr *sap = (struct sockaddr *)&address;
 918	__be32 *p;
 919	u32 len;
 920
 921	rpcb->r_port = 0;
 922
 923	p = xdr_inline_decode(xdr, 4);
 924	if (unlikely(p == NULL))
 925		goto out_fail;
 926	len = be32_to_cpup(p);
 927
 928	/*
 929	 * If the returned universal address is a null string,
 930	 * the requested RPC service was not registered.
 931	 */
 932	if (len == 0)
 933		return 0;
 934
 935	if (unlikely(len > RPCBIND_MAXUADDRLEN))
 936		goto out_fail;
 937
 938	p = xdr_inline_decode(xdr, len);
 939	if (unlikely(p == NULL))
 940		goto out_fail;
 941
 942	if (rpc_uaddr2sockaddr(req->rq_xprt->xprt_net, (char *)p, len,
 943				sap, sizeof(address)) == 0)
 944		goto out_fail;
 945	rpcb->r_port = rpc_get_port(sap);
 946
 947	return 0;
 948
 949out_fail:
 950	return -EIO;
 951}
 952
 953/*
 954 * Not all rpcbind procedures described in RFC 1833 are implemented
 955 * since the Linux kernel RPC code requires only these.
 956 */
 957
 958static const struct rpc_procinfo rpcb_procedures2[] = {
 959	[RPCBPROC_SET] = {
 960		.p_proc		= RPCBPROC_SET,
 961		.p_encode	= rpcb_enc_mapping,
 962		.p_decode	= rpcb_dec_set,
 963		.p_arglen	= RPCB_mappingargs_sz,
 964		.p_replen	= RPCB_setres_sz,
 965		.p_statidx	= RPCBPROC_SET,
 966		.p_timer	= 0,
 967		.p_name		= "SET",
 968	},
 969	[RPCBPROC_UNSET] = {
 970		.p_proc		= RPCBPROC_UNSET,
 971		.p_encode	= rpcb_enc_mapping,
 972		.p_decode	= rpcb_dec_set,
 973		.p_arglen	= RPCB_mappingargs_sz,
 974		.p_replen	= RPCB_setres_sz,
 975		.p_statidx	= RPCBPROC_UNSET,
 976		.p_timer	= 0,
 977		.p_name		= "UNSET",
 978	},
 979	[RPCBPROC_GETPORT] = {
 980		.p_proc		= RPCBPROC_GETPORT,
 981		.p_encode	= rpcb_enc_mapping,
 982		.p_decode	= rpcb_dec_getport,
 983		.p_arglen	= RPCB_mappingargs_sz,
 984		.p_replen	= RPCB_getportres_sz,
 985		.p_statidx	= RPCBPROC_GETPORT,
 986		.p_timer	= 0,
 987		.p_name		= "GETPORT",
 988	},
 989};
 990
 991static const struct rpc_procinfo rpcb_procedures3[] = {
 992	[RPCBPROC_SET] = {
 993		.p_proc		= RPCBPROC_SET,
 994		.p_encode	= rpcb_enc_getaddr,
 995		.p_decode	= rpcb_dec_set,
 996		.p_arglen	= RPCB_getaddrargs_sz,
 997		.p_replen	= RPCB_setres_sz,
 998		.p_statidx	= RPCBPROC_SET,
 999		.p_timer	= 0,
1000		.p_name		= "SET",
1001	},
1002	[RPCBPROC_UNSET] = {
1003		.p_proc		= RPCBPROC_UNSET,
1004		.p_encode	= rpcb_enc_getaddr,
1005		.p_decode	= rpcb_dec_set,
1006		.p_arglen	= RPCB_getaddrargs_sz,
1007		.p_replen	= RPCB_setres_sz,
1008		.p_statidx	= RPCBPROC_UNSET,
1009		.p_timer	= 0,
1010		.p_name		= "UNSET",
1011	},
1012	[RPCBPROC_GETADDR] = {
1013		.p_proc		= RPCBPROC_GETADDR,
1014		.p_encode	= rpcb_enc_getaddr,
1015		.p_decode	= rpcb_dec_getaddr,
1016		.p_arglen	= RPCB_getaddrargs_sz,
1017		.p_replen	= RPCB_getaddrres_sz,
1018		.p_statidx	= RPCBPROC_GETADDR,
1019		.p_timer	= 0,
1020		.p_name		= "GETADDR",
1021	},
1022};
1023
1024static const struct rpc_procinfo rpcb_procedures4[] = {
1025	[RPCBPROC_SET] = {
1026		.p_proc		= RPCBPROC_SET,
1027		.p_encode	= rpcb_enc_getaddr,
1028		.p_decode	= rpcb_dec_set,
1029		.p_arglen	= RPCB_getaddrargs_sz,
1030		.p_replen	= RPCB_setres_sz,
1031		.p_statidx	= RPCBPROC_SET,
1032		.p_timer	= 0,
1033		.p_name		= "SET",
1034	},
1035	[RPCBPROC_UNSET] = {
1036		.p_proc		= RPCBPROC_UNSET,
1037		.p_encode	= rpcb_enc_getaddr,
1038		.p_decode	= rpcb_dec_set,
1039		.p_arglen	= RPCB_getaddrargs_sz,
1040		.p_replen	= RPCB_setres_sz,
1041		.p_statidx	= RPCBPROC_UNSET,
1042		.p_timer	= 0,
1043		.p_name		= "UNSET",
1044	},
1045	[RPCBPROC_GETADDR] = {
1046		.p_proc		= RPCBPROC_GETADDR,
1047		.p_encode	= rpcb_enc_getaddr,
1048		.p_decode	= rpcb_dec_getaddr,
1049		.p_arglen	= RPCB_getaddrargs_sz,
1050		.p_replen	= RPCB_getaddrres_sz,
1051		.p_statidx	= RPCBPROC_GETADDR,
1052		.p_timer	= 0,
1053		.p_name		= "GETADDR",
1054	},
1055};
1056
1057static const struct rpcb_info rpcb_next_version[] = {
1058	{
1059		.rpc_vers	= RPCBVERS_2,
1060		.rpc_proc	= &rpcb_procedures2[RPCBPROC_GETPORT],
1061	},
1062	{
1063		.rpc_proc	= NULL,
1064	},
1065};
1066
1067static const struct rpcb_info rpcb_next_version6[] = {
1068	{
1069		.rpc_vers	= RPCBVERS_4,
1070		.rpc_proc	= &rpcb_procedures4[RPCBPROC_GETADDR],
1071	},
1072	{
1073		.rpc_vers	= RPCBVERS_3,
1074		.rpc_proc	= &rpcb_procedures3[RPCBPROC_GETADDR],
1075	},
1076	{
1077		.rpc_proc	= NULL,
1078	},
1079};
1080
1081static unsigned int rpcb_version2_counts[ARRAY_SIZE(rpcb_procedures2)];
1082static const struct rpc_version rpcb_version2 = {
1083	.number		= RPCBVERS_2,
1084	.nrprocs	= ARRAY_SIZE(rpcb_procedures2),
1085	.procs		= rpcb_procedures2,
1086	.counts		= rpcb_version2_counts,
1087};
1088
1089static unsigned int rpcb_version3_counts[ARRAY_SIZE(rpcb_procedures3)];
1090static const struct rpc_version rpcb_version3 = {
1091	.number		= RPCBVERS_3,
1092	.nrprocs	= ARRAY_SIZE(rpcb_procedures3),
1093	.procs		= rpcb_procedures3,
1094	.counts		= rpcb_version3_counts,
1095};
1096
1097static unsigned int rpcb_version4_counts[ARRAY_SIZE(rpcb_procedures4)];
1098static const struct rpc_version rpcb_version4 = {
1099	.number		= RPCBVERS_4,
1100	.nrprocs	= ARRAY_SIZE(rpcb_procedures4),
1101	.procs		= rpcb_procedures4,
1102	.counts		= rpcb_version4_counts,
1103};
1104
1105static const struct rpc_version *rpcb_version[] = {
1106	NULL,
1107	NULL,
1108	&rpcb_version2,
1109	&rpcb_version3,
1110	&rpcb_version4
1111};
1112
1113static struct rpc_stat rpcb_stats;
1114
1115static const struct rpc_program rpcb_program = {
1116	.name		= "rpcbind",
1117	.number		= RPCBIND_PROGRAM,
1118	.nrvers		= ARRAY_SIZE(rpcb_version),
1119	.version	= rpcb_version,
1120	.stats		= &rpcb_stats,
1121};