// 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/lockd/lockd.h> #include <asm/unaligned.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, }; 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; 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 nlm_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 http://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) { struct nsm_res *resp = data; __be32 *p; p = xdr_inline_decode(xdr, 4 + 4); if (unlikely(p == NULL)) return -EIO; resp->status = be32_to_cpup(p++); resp->state = be32_to_cpup(p); dprintk("lockd: %s status %d state %d\n", __func__, resp->status, resp->state); return 0; } static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp, struct xdr_stream *xdr, void *data) { struct nsm_res *resp = data; __be32 *p; p = xdr_inline_decode(xdr, 4); if (unlikely(p == NULL)) return -EIO; resp->state = be32_to_cpup(p); dprintk("lockd: %s state %d\n", __func__, resp->state); return 0; } #define SM_my_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) #define SM_my_id_sz (SM_my_name_sz+3) #define SM_mon_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) #define SM_mon_id_sz (SM_mon_name_sz+SM_my_id_sz) #define SM_priv_sz (XDR_QUADLEN(SM_PRIV_SIZE)) #define SM_mon_sz (SM_mon_id_sz+SM_priv_sz) #define SM_monres_sz 2 #define SM_unmonres_sz 1 static const struct rpc_procinfo nsm_procedures[] = { [NSMPROC_MON] = { .p_proc = NSMPROC_MON, .p_encode = nsm_xdr_enc_mon, .p_decode = nsm_xdr_dec_stat_res, .p_arglen = SM_mon_sz, .p_replen = SM_monres_sz, .p_statidx = NSMPROC_MON, .p_name = "MONITOR", }, [NSMPROC_UNMON] = { .p_proc = NSMPROC_UNMON, .p_encode = nsm_xdr_enc_unmon, .p_decode = nsm_xdr_dec_stat, .p_arglen = SM_mon_id_sz, .p_replen = SM_unmonres_sz, .p_statidx = NSMPROC_UNMON, .p_name = "UNMONITOR", }, }; static unsigned int nsm_version1_counts[ARRAY_SIZE(nsm_procedures)]; static const struct rpc_version nsm_version1 = { .number = 1, .nrprocs = ARRAY_SIZE(nsm_procedures), .procs = nsm_procedures, .counts = nsm_version1_counts, }; static const struct rpc_version *nsm_version[] = { [1] = &nsm_version1, }; static struct rpc_stat nsm_stats; static const struct rpc_program nsm_program = { .name = "statd", .number = NSM_PROGRAM, .nrvers = ARRAY_SIZE(nsm_version), .version = nsm_version, .stats = &nsm_stats };