// SPDX-License-Identifier: GPL-2.0/* * linux/fs/lockd/mon.c * * The kernel statd client. * * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> */ #include <linux/types.h>#include <linux/kernel.h>#include <linux/ktime.h>#include <linux/slab.h> #include <linux/sunrpc/clnt.h>#include <linux/sunrpc/addr.h>#include <linux/sunrpc/xprtsock.h>#include <linux/sunrpc/svc.h> #include <linux/unaligned.h> #include "lockd.h"#include "netns.h" #define NLMDBG_FACILITY		NLMDBG_MONITOR#define NSM_PROGRAM		100024#define NSM_VERSION		1 enum {	NSMPROC_NULL,	NSMPROC_STAT,	NSMPROC_MON,	NSMPROC_UNMON,	NSMPROC_UNMON_ALL,	NSMPROC_SIMU_CRASH,	NSMPROC_NOTIFY,}; struct nsm_args {	struct nsm_private	*priv;	u32			prog;		/* RPC callback info */	u32			vers;	u32			proc; 	char			*mon_name;	const char		*nodename;}; struct nsm_res {	u32			status;	u32			state;}; static const struct rpc_program	nsm_program;static				DEFINE_SPINLOCK(nsm_lock); /* * Local NSM state */u32	__read_mostly		nsm_local_state;bool	__read_mostly		nsm_use_hostnames; static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm){	return (struct sockaddr *)&nsm->sm_addr;} static struct rpc_clnt *nsm_create(struct net *net, const char *nodename){	struct sockaddr_in sin = {		.sin_family		= AF_INET,		.sin_addr.s_addr	= htonl(INADDR_LOOPBACK),	};	struct rpc_create_args args = {		.net			= net,		.protocol		= XPRT_TRANSPORT_TCP,		.address		= (struct sockaddr *)&sin,		.addrsize		= sizeof(sin),		.servername		= "rpc.statd",		.nodename		= nodename,		.program		= &nsm_program,		.version		= NSM_VERSION,		.authflavor		= RPC_AUTH_NULL,		.flags			= RPC_CLNT_CREATE_NOPING,		.cred			= current_cred(),	}; 	return rpc_create(&args);} static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res,			 const struct nlm_host *host){	int		status;	struct rpc_clnt *clnt;	struct nsm_args args = {		.priv		= &nsm->sm_priv,		.prog		= NLM_PROGRAM,		.vers		= 3,		.proc		= NLMPROC_NSM_NOTIFY,		.mon_name	= nsm->sm_mon_name,		.nodename	= host->nodename,	};	struct rpc_message msg = {		.rpc_argp	= &args,		.rpc_resp	= res,	}; 	memset(res, 0, sizeof(*res)); 	clnt = nsm_create(host->net, host->nodename);	if (IS_ERR(clnt)) {		dprintk("lockd: failed to create NSM upcall transport, "			"status=%ld, net=%x\n", PTR_ERR(clnt),			host->net->ns.inum);		return PTR_ERR(clnt);	} 	msg.rpc_proc = &clnt->cl_procinfo[proc];	status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN);	if (status == -ECONNREFUSED) {		dprintk("lockd:	NSM upcall RPC failed, status=%d, forcing rebind\n",				status);		rpc_force_rebind(clnt);		status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN);	}	if (status < 0)		dprintk("lockd: NSM upcall RPC failed, status=%d\n",				status);	else		status = 0; 	rpc_shutdown_client(clnt);	return status;} /** * nsm_monitor - Notify a peer in case we reboot * @host: pointer to nlm_host of peer to notify * * If this peer is not already monitored, this function sends an * upcall to the local rpc.statd to record the name/address of * the peer to notify in case we reboot. * * Returns zero if the peer is monitored by the local rpc.statd; * otherwise a negative errno value is returned. */int nsm_monitor(const struct nlm_host *host){	struct nsm_handle *nsm = host->h_nsmhandle;	struct nsm_res	res;	int		status; 	dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name); 	if (nsm->sm_monitored)		return 0; 	/*	 * Choose whether to record the caller_name or IP address of	 * this peer in the local rpc.statd's database.	 */	nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf; 	status = nsm_mon_unmon(nsm, NSMPROC_MON, &res, host);	if (unlikely(res.status != 0))		status = -EIO;	if (unlikely(status < 0)) {		pr_notice_ratelimited("lockd: cannot monitor %s\n", nsm->sm_name);		return status;	} 	nsm->sm_monitored = 1;	if (unlikely(nsm_local_state != res.state)) {		nsm_local_state = res.state;		dprintk("lockd: NSM state changed to %d\n", nsm_local_state);	}	return 0;} /** * nsm_unmonitor - Unregister peer notification * @host: pointer to nlm_host of peer to stop monitoring * * If this peer is monitored, this function sends an upcall to * tell the local rpc.statd not to send this peer a notification * when we reboot. */void nsm_unmonitor(const struct nlm_host *host){	struct nsm_handle *nsm = host->h_nsmhandle;	struct nsm_res	res;	int status; 	if (refcount_read(&nsm->sm_count) == 1	 && nsm->sm_monitored && !nsm->sm_sticky) {		dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name); 		status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res, host);		if (res.status != 0)			status = -EIO;		if (status < 0)			printk(KERN_NOTICE "lockd: cannot unmonitor %s\n",					nsm->sm_name);		else			nsm->sm_monitored = 0;	}} static struct nsm_handle *nsm_lookup_hostname(const struct list_head *nsm_handles,					const char *hostname, const size_t len){	struct nsm_handle *nsm; 	list_for_each_entry(nsm, nsm_handles, sm_link)		if (strlen(nsm->sm_name) == len &&		    memcmp(nsm->sm_name, hostname, len) == 0)			return nsm;	return NULL;} static struct nsm_handle *nsm_lookup_addr(const struct list_head *nsm_handles,					const struct sockaddr *sap){	struct nsm_handle *nsm; 	list_for_each_entry(nsm, nsm_handles, sm_link)		if (rpc_cmp_addr(nsm_addr(nsm), sap))			return nsm;	return NULL;} static struct nsm_handle *nsm_lookup_priv(const struct list_head *nsm_handles,					const struct nsm_private *priv){	struct nsm_handle *nsm; 	list_for_each_entry(nsm, nsm_handles, sm_link)		if (memcmp(nsm->sm_priv.data, priv->data,					sizeof(priv->data)) == 0)			return nsm;	return NULL;} /* * Construct a unique cookie to match this nsm_handle to this monitored * host.  It is passed to the local rpc.statd via NSMPROC_MON, and * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these * requests. * * The NSM protocol requires that these cookies be unique while the * system is running.  We prefer a stronger requirement of making them * unique across reboots.  If user space bugs cause a stale cookie to * be sent to the kernel, it could cause the wrong host to lose its * lock state if cookies were not unique across reboots. * * The cookies are exposed only to local user space via loopback.  They * do not appear on the physical network.  If we want greater security * for some reason, nsm_init_private() could perform a one-way hash to * obscure the contents of the cookie. */static void nsm_init_private(struct nsm_handle *nsm){	u64 *p = (u64 *)&nsm->sm_priv.data;	s64 ns; 	ns = ktime_get_ns();	put_unaligned(ns, p);	put_unaligned((unsigned long)nsm, p + 1);} static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap,					    const size_t salen,					    const char *hostname,					    const size_t hostname_len){	struct nsm_handle *new; 	if (!hostname)		return NULL; 	new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL);	if (unlikely(new == NULL))		return NULL; 	refcount_set(&new->sm_count, 1);	new->sm_name = (char *)(new + 1);	memcpy(nsm_addr(new), sap, salen);	new->sm_addrlen = salen;	nsm_init_private(new); 	if (rpc_ntop(nsm_addr(new), new->sm_addrbuf,					sizeof(new->sm_addrbuf)) == 0)		(void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf),				"unsupported address family");	memcpy(new->sm_name, hostname, hostname_len);	new->sm_name[hostname_len] = '\0'; 	return new;} /** * nsm_get_handle - Find or create a cached nsm_handle * @net: network namespace * @sap: pointer to socket address of handle to find * @salen: length of socket address * @hostname: pointer to C string containing hostname to find * @hostname_len: length of C string * * Behavior is modulated by the global nsm_use_hostnames variable. * * Returns a cached nsm_handle after bumping its ref count, or * returns a fresh nsm_handle if a handle that matches @sap and/or * @hostname cannot be found in the handle cache.  Returns NULL if * an error occurs. */struct nsm_handle *nsm_get_handle(const struct net *net,				  const struct sockaddr *sap,				  const size_t salen, const char *hostname,				  const size_t hostname_len){	struct nsm_handle *cached, *new = NULL;	struct lockd_net *ln = net_generic(net, lockd_net_id); 	if (hostname && memchr(hostname, '/', hostname_len) != NULL) {		if (printk_ratelimit()) {			printk(KERN_WARNING "Invalid hostname \"%.*s\" "					    "in NFS lock request\n",				(int)hostname_len, hostname);		}		return NULL;	} retry:	spin_lock(&nsm_lock); 	if (nsm_use_hostnames && hostname != NULL)		cached = nsm_lookup_hostname(&ln->nsm_handles,					hostname, hostname_len);	else		cached = nsm_lookup_addr(&ln->nsm_handles, sap); 	if (cached != NULL) {		refcount_inc(&cached->sm_count);		spin_unlock(&nsm_lock);		kfree(new);		dprintk("lockd: found nsm_handle for %s (%s), "				"cnt %d\n", cached->sm_name,				cached->sm_addrbuf,				refcount_read(&cached->sm_count));		return cached;	} 	if (new != NULL) {		list_add(&new->sm_link, &ln->nsm_handles);		spin_unlock(&nsm_lock);		dprintk("lockd: created nsm_handle for %s (%s)\n",				new->sm_name, new->sm_addrbuf);		return new;	} 	spin_unlock(&nsm_lock); 	new = nsm_create_handle(sap, salen, hostname, hostname_len);	if (unlikely(new == NULL))		return NULL;	goto retry;} /** * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle * @net:  network namespace * @info: pointer to NLMPROC_SM_NOTIFY arguments * * Returns a matching nsm_handle if found in the nsm cache. The returned * nsm_handle's reference count is bumped. Otherwise returns NULL if some * error occurred. */struct nsm_handle *nsm_reboot_lookup(const struct net *net,				const struct lockd_reboot *info){	struct nsm_handle *cached;	struct lockd_net *ln = net_generic(net, lockd_net_id); 	spin_lock(&nsm_lock); 	cached = nsm_lookup_priv(&ln->nsm_handles, &info->priv);	if (unlikely(cached == NULL)) {		spin_unlock(&nsm_lock);		dprintk("lockd: never saw rebooted peer '%.*s' before\n",				info->len, info->mon);		return cached;	} 	refcount_inc(&cached->sm_count);	spin_unlock(&nsm_lock); 	dprintk("lockd: host %s (%s) rebooted, cnt %d\n",			cached->sm_name, cached->sm_addrbuf,			refcount_read(&cached->sm_count));	return cached;} /** * nsm_release - Release an NSM handle * @nsm: pointer to handle to be released * */void nsm_release(struct nsm_handle *nsm){	if (refcount_dec_and_lock(&nsm->sm_count, &nsm_lock)) {		list_del(&nsm->sm_link);		spin_unlock(&nsm_lock);		dprintk("lockd: destroyed nsm_handle for %s (%s)\n",				nsm->sm_name, nsm->sm_addrbuf);		kfree(nsm);	}} /* * XDR functions for NSM. * * See https://www.opengroup.org/ for details on the Network * Status Monitor wire protocol. */ static void encode_nsm_string(struct xdr_stream *xdr, const char *string){	const u32 len = strlen(string);	__be32 *p; 	p = xdr_reserve_space(xdr, 4 + len);	xdr_encode_opaque(p, string, len);} /* * "mon_name" specifies the host to be monitored. */static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp){	encode_nsm_string(xdr, argp->mon_name);} /* * The "my_id" argument specifies the hostname and RPC procedure * to be called when the status manager receives notification * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name" * has changed. */static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp){	__be32 *p; 	encode_nsm_string(xdr, argp->nodename);	p = xdr_reserve_space(xdr, 4 + 4 + 4);	*p++ = cpu_to_be32(argp->prog);	*p++ = cpu_to_be32(argp->vers);	*p = cpu_to_be32(argp->proc);} /* * The "mon_id" argument specifies the non-private arguments * of an NSMPROC_MON or NSMPROC_UNMON call. */static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp){	encode_mon_name(xdr, argp);	encode_my_id(xdr, argp);} /* * The "priv" argument may contain private information required * by the NSMPROC_MON call. This information will be supplied in the * NLMPROC_SM_NOTIFY call. */static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp){	__be32 *p; 	p = xdr_reserve_space(xdr, SM_PRIV_SIZE);	xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE);} static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr,			    const void *argp){	encode_mon_id(xdr, argp);	encode_priv(xdr, argp);} static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr,			      const void *argp){	encode_mon_id(xdr, argp);} static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp,				struct xdr_stream *xdr,				void *data){

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