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-rw-r--r--fs/nfs/callback.c414
1 files changed, 414 insertions, 0 deletions
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
new file mode 100644
index 0000000000..466ebf1d41
--- /dev/null
+++ b/fs/nfs/callback.c
@@ -0,0 +1,414 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/nfs/callback.c
+ *
+ * Copyright (C) 2004 Trond Myklebust
+ *
+ * NFSv4 callback handling
+ */
+
+#include <linux/completion.h>
+#include <linux/ip.h>
+#include <linux/module.h>
+#include <linux/sched/signal.h>
+#include <linux/sunrpc/svc.h>
+#include <linux/sunrpc/svcsock.h>
+#include <linux/nfs_fs.h>
+#include <linux/errno.h>
+#include <linux/mutex.h>
+#include <linux/freezer.h>
+#include <linux/sunrpc/svcauth_gss.h>
+#include <linux/sunrpc/bc_xprt.h>
+
+#include <net/inet_sock.h>
+
+#include "nfs4_fs.h"
+#include "callback.h"
+#include "internal.h"
+#include "netns.h"
+
+#define NFSDBG_FACILITY NFSDBG_CALLBACK
+
+struct nfs_callback_data {
+ unsigned int users;
+ struct svc_serv *serv;
+};
+
+static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
+static DEFINE_MUTEX(nfs_callback_mutex);
+static struct svc_program nfs4_callback_program;
+
+static int nfs4_callback_up_net(struct svc_serv *serv, struct net *net)
+{
+ const struct cred *cred = current_cred();
+ int ret;
+ struct nfs_net *nn = net_generic(net, nfs_net_id);
+
+ ret = svc_xprt_create(serv, "tcp", net, PF_INET,
+ nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS,
+ cred);
+ if (ret <= 0)
+ goto out_err;
+ nn->nfs_callback_tcpport = ret;
+ dprintk("NFS: Callback listener port = %u (af %u, net %x)\n",
+ nn->nfs_callback_tcpport, PF_INET, net->ns.inum);
+
+ ret = svc_xprt_create(serv, "tcp", net, PF_INET6,
+ nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS,
+ cred);
+ if (ret > 0) {
+ nn->nfs_callback_tcpport6 = ret;
+ dprintk("NFS: Callback listener port = %u (af %u, net %x)\n",
+ nn->nfs_callback_tcpport6, PF_INET6, net->ns.inum);
+ } else if (ret != -EAFNOSUPPORT)
+ goto out_err;
+ return 0;
+
+out_err:
+ return (ret) ? ret : -ENOMEM;
+}
+
+/*
+ * This is the NFSv4 callback kernel thread.
+ */
+static int
+nfs4_callback_svc(void *vrqstp)
+{
+ struct svc_rqst *rqstp = vrqstp;
+
+ set_freezable();
+
+ while (!kthread_freezable_should_stop(NULL))
+ svc_recv(rqstp);
+
+ svc_exit_thread(rqstp);
+ return 0;
+}
+
+#if defined(CONFIG_NFS_V4_1)
+/*
+ * The callback service for NFSv4.1 callbacks
+ */
+static int
+nfs41_callback_svc(void *vrqstp)
+{
+ struct svc_rqst *rqstp = vrqstp;
+ struct svc_serv *serv = rqstp->rq_server;
+ struct rpc_rqst *req;
+ int error;
+ DEFINE_WAIT(wq);
+
+ set_freezable();
+
+ while (!kthread_freezable_should_stop(NULL)) {
+ prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_IDLE);
+ spin_lock_bh(&serv->sv_cb_lock);
+ if (!list_empty(&serv->sv_cb_list)) {
+ req = list_first_entry(&serv->sv_cb_list,
+ struct rpc_rqst, rq_bc_list);
+ list_del(&req->rq_bc_list);
+ spin_unlock_bh(&serv->sv_cb_lock);
+ finish_wait(&serv->sv_cb_waitq, &wq);
+ dprintk("Invoking bc_svc_process()\n");
+ error = bc_svc_process(serv, req, rqstp);
+ dprintk("bc_svc_process() returned w/ error code= %d\n",
+ error);
+ } else {
+ spin_unlock_bh(&serv->sv_cb_lock);
+ if (!kthread_should_stop())
+ schedule();
+ finish_wait(&serv->sv_cb_waitq, &wq);
+ }
+ }
+
+ svc_exit_thread(rqstp);
+ return 0;
+}
+
+static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
+ struct svc_serv *serv)
+{
+ if (minorversion)
+ /*
+ * Save the svc_serv in the transport so that it can
+ * be referenced when the session backchannel is initialized
+ */
+ xprt->bc_serv = serv;
+}
+#else
+static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
+ struct svc_serv *serv)
+{
+}
+#endif /* CONFIG_NFS_V4_1 */
+
+static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
+ struct svc_serv *serv)
+{
+ int nrservs = nfs_callback_nr_threads;
+ int ret;
+
+ nfs_callback_bc_serv(minorversion, xprt, serv);
+
+ if (nrservs < NFS4_MIN_NR_CALLBACK_THREADS)
+ nrservs = NFS4_MIN_NR_CALLBACK_THREADS;
+
+ if (serv->sv_nrthreads == nrservs)
+ return 0;
+
+ ret = svc_set_num_threads(serv, NULL, nrservs);
+ if (ret) {
+ svc_set_num_threads(serv, NULL, 0);
+ return ret;
+ }
+ dprintk("nfs_callback_up: service started\n");
+ return 0;
+}
+
+static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net)
+{
+ struct nfs_net *nn = net_generic(net, nfs_net_id);
+
+ if (--nn->cb_users[minorversion])
+ return;
+
+ dprintk("NFS: destroy per-net callback data; net=%x\n", net->ns.inum);
+ svc_xprt_destroy_all(serv, net);
+}
+
+static int nfs_callback_up_net(int minorversion, struct svc_serv *serv,
+ struct net *net, struct rpc_xprt *xprt)
+{
+ struct nfs_net *nn = net_generic(net, nfs_net_id);
+ int ret;
+
+ if (nn->cb_users[minorversion]++)
+ return 0;
+
+ dprintk("NFS: create per-net callback data; net=%x\n", net->ns.inum);
+
+ ret = svc_bind(serv, net);
+ if (ret < 0) {
+ printk(KERN_WARNING "NFS: bind callback service failed\n");
+ goto err_bind;
+ }
+
+ ret = 0;
+ if (!IS_ENABLED(CONFIG_NFS_V4_1) || minorversion == 0)
+ ret = nfs4_callback_up_net(serv, net);
+ else if (xprt->ops->bc_setup)
+ set_bc_enabled(serv);
+ else
+ ret = -EPROTONOSUPPORT;
+
+ if (ret < 0) {
+ printk(KERN_ERR "NFS: callback service start failed\n");
+ goto err_socks;
+ }
+ return 0;
+
+err_socks:
+ svc_rpcb_cleanup(serv, net);
+err_bind:
+ nn->cb_users[minorversion]--;
+ dprintk("NFS: Couldn't create callback socket: err = %d; "
+ "net = %x\n", ret, net->ns.inum);
+ return ret;
+}
+
+static struct svc_serv *nfs_callback_create_svc(int minorversion)
+{
+ struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
+ int (*threadfn)(void *data);
+ struct svc_serv *serv;
+
+ /*
+ * Check whether we're already up and running.
+ */
+ if (cb_info->serv)
+ return svc_get(cb_info->serv);
+
+ /*
+ * Sanity check: if there's no task,
+ * we should be the first user ...
+ */
+ if (cb_info->users)
+ printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
+ cb_info->users);
+
+ threadfn = nfs4_callback_svc;
+#if defined(CONFIG_NFS_V4_1)
+ if (minorversion)
+ threadfn = nfs41_callback_svc;
+#else
+ if (minorversion)
+ return ERR_PTR(-ENOTSUPP);
+#endif
+ serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE,
+ threadfn);
+ if (!serv) {
+ printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
+ return ERR_PTR(-ENOMEM);
+ }
+ cb_info->serv = serv;
+ /* As there is only one thread we need to over-ride the
+ * default maximum of 80 connections
+ */
+ serv->sv_maxconn = 1024;
+ dprintk("nfs_callback_create_svc: service created\n");
+ return serv;
+}
+
+/*
+ * Bring up the callback thread if it is not already up.
+ */
+int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
+{
+ struct svc_serv *serv;
+ struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
+ int ret;
+ struct net *net = xprt->xprt_net;
+
+ mutex_lock(&nfs_callback_mutex);
+
+ serv = nfs_callback_create_svc(minorversion);
+ if (IS_ERR(serv)) {
+ ret = PTR_ERR(serv);
+ goto err_create;
+ }
+
+ ret = nfs_callback_up_net(minorversion, serv, net, xprt);
+ if (ret < 0)
+ goto err_net;
+
+ ret = nfs_callback_start_svc(minorversion, xprt, serv);
+ if (ret < 0)
+ goto err_start;
+
+ cb_info->users++;
+err_net:
+ if (!cb_info->users)
+ cb_info->serv = NULL;
+ svc_put(serv);
+err_create:
+ mutex_unlock(&nfs_callback_mutex);
+ return ret;
+
+err_start:
+ nfs_callback_down_net(minorversion, serv, net);
+ dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
+ goto err_net;
+}
+
+/*
+ * Kill the callback thread if it's no longer being used.
+ */
+void nfs_callback_down(int minorversion, struct net *net)
+{
+ struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
+ struct svc_serv *serv;
+
+ mutex_lock(&nfs_callback_mutex);
+ serv = cb_info->serv;
+ nfs_callback_down_net(minorversion, serv, net);
+ cb_info->users--;
+ if (cb_info->users == 0) {
+ svc_get(serv);
+ svc_set_num_threads(serv, NULL, 0);
+ svc_put(serv);
+ dprintk("nfs_callback_down: service destroyed\n");
+ cb_info->serv = NULL;
+ }
+ mutex_unlock(&nfs_callback_mutex);
+}
+
+/* Boolean check of RPC_AUTH_GSS principal */
+int
+check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
+{
+ char *p = rqstp->rq_cred.cr_principal;
+
+ if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
+ return 1;
+
+ /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
+ if (clp->cl_minorversion != 0)
+ return 0;
+ /*
+ * It might just be a normal user principal, in which case
+ * userspace won't bother to tell us the name at all.
+ */
+ if (p == NULL)
+ return 0;
+
+ /*
+ * Did we get the acceptor from userland during the SETCLIENID
+ * negotiation?
+ */
+ if (clp->cl_acceptor)
+ return !strcmp(p, clp->cl_acceptor);
+
+ /*
+ * Otherwise try to verify it using the cl_hostname. Note that this
+ * doesn't work if a non-canonical hostname was used in the devname.
+ */
+
+ /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
+
+ if (memcmp(p, "nfs@", 4) != 0)
+ return 0;
+ p += 4;
+ if (strcmp(p, clp->cl_hostname) != 0)
+ return 0;
+ return 1;
+}
+
+/*
+ * pg_authenticate method for nfsv4 callback threads.
+ *
+ * The authflavor has been negotiated, so an incorrect flavor is a server
+ * bug. Deny packets with incorrect authflavor.
+ *
+ * All other checking done after NFS decoding where the nfs_client can be
+ * found in nfs4_callback_compound
+ */
+static enum svc_auth_status nfs_callback_authenticate(struct svc_rqst *rqstp)
+{
+ rqstp->rq_auth_stat = rpc_autherr_badcred;
+
+ switch (rqstp->rq_authop->flavour) {
+ case RPC_AUTH_NULL:
+ if (rqstp->rq_proc != CB_NULL)
+ return SVC_DENIED;
+ break;
+ case RPC_AUTH_GSS:
+ /* No RPC_AUTH_GSS support yet in NFSv4.1 */
+ if (svc_is_backchannel(rqstp))
+ return SVC_DENIED;
+ }
+
+ rqstp->rq_auth_stat = rpc_auth_ok;
+ return SVC_OK;
+}
+
+/*
+ * Define NFS4 callback program
+ */
+static const struct svc_version *nfs4_callback_version[] = {
+ [1] = &nfs4_callback_version1,
+ [4] = &nfs4_callback_version4,
+};
+
+static struct svc_stat nfs4_callback_stats;
+
+static struct svc_program nfs4_callback_program = {
+ .pg_prog = NFS4_CALLBACK, /* RPC service number */
+ .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */
+ .pg_vers = nfs4_callback_version, /* version table */
+ .pg_name = "NFSv4 callback", /* service name */
+ .pg_class = "nfs", /* authentication class */
+ .pg_stats = &nfs4_callback_stats,
+ .pg_authenticate = nfs_callback_authenticate,
+ .pg_init_request = svc_generic_init_request,
+ .pg_rpcbind_set = svc_generic_rpcbind_set,
+};