diff options
Diffstat (limited to 'fs/nfs/callback.c')
| -rw-r--r-- | fs/nfs/callback.c | 414 |
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, +}; |