| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * linux/fs/nfs/callback.c |
| 4 | * |
| 5 | * Copyright (C) 2004 Trond Myklebust |
| 6 | * |
| 7 | * NFSv4 callback handling |
| 8 | */ |
| 9 | |
| 10 | #include <linux/completion.h> |
| 11 | #include <linux/ip.h> |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/sched/signal.h> |
| 14 | #include <linux/sunrpc/svc.h> |
| 15 | #include <linux/sunrpc/svcsock.h> |
| 16 | #include <linux/nfs_fs.h> |
| 17 | #include <linux/errno.h> |
| 18 | #include <linux/mutex.h> |
| 19 | #include <linux/freezer.h> |
| 20 | #include <linux/sunrpc/svcauth_gss.h> |
| 21 | #include <linux/sunrpc/bc_xprt.h> |
| 22 | |
| 23 | #include <net/inet_sock.h> |
| 24 | |
| 25 | #include "nfs4_fs.h" |
| 26 | #include "callback.h" |
| 27 | #include "internal.h" |
| 28 | #include "netns.h" |
| 29 | |
| 30 | #define NFSDBG_FACILITY NFSDBG_CALLBACK |
| 31 | |
| 32 | struct nfs_callback_data { |
| 33 | unsigned int users; |
| 34 | struct svc_serv *serv; |
| 35 | }; |
| 36 | |
| 37 | static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1]; |
| 38 | static DEFINE_MUTEX(nfs_callback_mutex); |
| 39 | static struct svc_program nfs4_callback_program; |
| 40 | |
| 41 | static int nfs4_callback_up_net(struct svc_serv *serv, struct net *net) |
| 42 | { |
| 43 | const struct cred *cred = current_cred(); |
| 44 | int ret; |
| 45 | struct nfs_net *nn = net_generic(net, nfs_net_id); |
| 46 | |
| 47 | ret = svc_xprt_create(serv, "tcp", net, PF_INET, |
| 48 | nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS, |
| 49 | cred); |
| 50 | if (ret <= 0) |
| 51 | goto out_err; |
| 52 | nn->nfs_callback_tcpport = ret; |
| 53 | dprintk("NFS: Callback listener port = %u (af %u, net %x)\n", |
| 54 | nn->nfs_callback_tcpport, PF_INET, net->ns.inum); |
| 55 | |
| 56 | ret = svc_xprt_create(serv, "tcp", net, PF_INET6, |
| 57 | nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS, |
| 58 | cred); |
| 59 | if (ret > 0) { |
| 60 | nn->nfs_callback_tcpport6 = ret; |
| 61 | dprintk("NFS: Callback listener port = %u (af %u, net %x)\n", |
| 62 | nn->nfs_callback_tcpport6, PF_INET6, net->ns.inum); |
| 63 | } else if (ret != -EAFNOSUPPORT) |
| 64 | goto out_err; |
| 65 | return 0; |
| 66 | |
| 67 | out_err: |
| 68 | return (ret) ? ret : -ENOMEM; |
| 69 | } |
| 70 | |
| 71 | /* |
| 72 | * This is the NFSv4 callback kernel thread. |
| 73 | */ |
| 74 | static int |
| 75 | nfs4_callback_svc(void *vrqstp) |
| 76 | { |
| 77 | struct svc_rqst *rqstp = vrqstp; |
| 78 | |
| 79 | svc_thread_init_status(rqstp, 0); |
| 80 | |
| 81 | set_freezable(); |
| 82 | |
| 83 | while (!svc_thread_should_stop(rqstp)) |
| 84 | svc_recv(rqstp); |
| 85 | |
| 86 | svc_exit_thread(rqstp); |
| 87 | return 0; |
| 88 | } |
| 89 | |
| 90 | #if defined(CONFIG_NFS_V4_1) |
| 91 | static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, |
| 92 | struct svc_serv *serv) |
| 93 | { |
| 94 | if (minorversion) |
| 95 | /* |
| 96 | * Save the svc_serv in the transport so that it can |
| 97 | * be referenced when the session backchannel is initialized |
| 98 | */ |
| 99 | xprt->bc_serv = serv; |
| 100 | } |
| 101 | #else |
| 102 | static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, |
| 103 | struct svc_serv *serv) |
| 104 | { |
| 105 | } |
| 106 | #endif /* CONFIG_NFS_V4_1 */ |
| 107 | |
| 108 | static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt, |
| 109 | struct svc_serv *serv) |
| 110 | { |
| 111 | int nrservs = nfs_callback_nr_threads; |
| 112 | int ret; |
| 113 | |
| 114 | nfs_callback_bc_serv(minorversion, xprt, serv); |
| 115 | |
| 116 | if (nrservs < NFS4_MIN_NR_CALLBACK_THREADS) |
| 117 | nrservs = NFS4_MIN_NR_CALLBACK_THREADS; |
| 118 | |
| 119 | if (serv->sv_nrthreads == nrservs) |
| 120 | return 0; |
| 121 | |
| 122 | ret = svc_set_num_threads(serv, NULL, nrservs); |
| 123 | if (ret) { |
| 124 | svc_set_num_threads(serv, NULL, 0); |
| 125 | return ret; |
| 126 | } |
| 127 | dprintk("nfs_callback_up: service started\n"); |
| 128 | return 0; |
| 129 | } |
| 130 | |
| 131 | static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net) |
| 132 | { |
| 133 | struct nfs_net *nn = net_generic(net, nfs_net_id); |
| 134 | |
| 135 | if (--nn->cb_users[minorversion]) |
| 136 | return; |
| 137 | |
| 138 | dprintk("NFS: destroy per-net callback data; net=%x\n", net->ns.inum); |
| 139 | svc_xprt_destroy_all(serv, net); |
| 140 | } |
| 141 | |
| 142 | static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, |
| 143 | struct net *net, struct rpc_xprt *xprt) |
| 144 | { |
| 145 | struct nfs_net *nn = net_generic(net, nfs_net_id); |
| 146 | int ret; |
| 147 | |
| 148 | if (nn->cb_users[minorversion]++) |
| 149 | return 0; |
| 150 | |
| 151 | dprintk("NFS: create per-net callback data; net=%x\n", net->ns.inum); |
| 152 | |
| 153 | ret = svc_bind(serv, net); |
| 154 | if (ret < 0) { |
| 155 | printk(KERN_WARNING "NFS: bind callback service failed\n"); |
| 156 | goto err_bind; |
| 157 | } |
| 158 | |
| 159 | ret = 0; |
| 160 | if (!IS_ENABLED(CONFIG_NFS_V4_1) || minorversion == 0) |
| 161 | ret = nfs4_callback_up_net(serv, net); |
| 162 | else if (xprt->ops->bc_setup) |
| 163 | set_bc_enabled(serv); |
| 164 | else |
| 165 | ret = -EPROTONOSUPPORT; |
| 166 | |
| 167 | if (ret < 0) { |
| 168 | printk(KERN_ERR "NFS: callback service start failed\n"); |
| 169 | goto err_socks; |
| 170 | } |
| 171 | return 0; |
| 172 | |
| 173 | err_socks: |
| 174 | svc_rpcb_cleanup(serv, net); |
| 175 | err_bind: |
| 176 | nn->cb_users[minorversion]--; |
| 177 | dprintk("NFS: Couldn't create callback socket: err = %d; " |
| 178 | "net = %x\n", ret, net->ns.inum); |
| 179 | return ret; |
| 180 | } |
| 181 | |
| 182 | static struct svc_serv *nfs_callback_create_svc(int minorversion) |
| 183 | { |
| 184 | struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; |
| 185 | int (*threadfn)(void *data); |
| 186 | struct svc_serv *serv; |
| 187 | |
| 188 | /* |
| 189 | * Check whether we're already up and running. |
| 190 | */ |
| 191 | if (cb_info->serv) |
| 192 | return cb_info->serv; |
| 193 | |
| 194 | /* |
| 195 | * Sanity check: if there's no task, |
| 196 | * we should be the first user ... |
| 197 | */ |
| 198 | if (cb_info->users) |
| 199 | printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n", |
| 200 | cb_info->users); |
| 201 | |
| 202 | threadfn = nfs4_callback_svc; |
| 203 | #if !defined(CONFIG_NFS_V4_1) |
| 204 | if (minorversion) |
| 205 | return ERR_PTR(-ENOTSUPP); |
| 206 | #endif |
| 207 | serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, |
| 208 | threadfn); |
| 209 | if (!serv) { |
| 210 | printk(KERN_ERR "nfs_callback_create_svc: create service failed\n"); |
| 211 | return ERR_PTR(-ENOMEM); |
| 212 | } |
| 213 | cb_info->serv = serv; |
| 214 | /* As there is only one thread we need to over-ride the |
| 215 | * default maximum of 80 connections |
| 216 | */ |
| 217 | serv->sv_maxconn = 1024; |
| 218 | dprintk("nfs_callback_create_svc: service created\n"); |
| 219 | return serv; |
| 220 | } |
| 221 | |
| 222 | /* |
| 223 | * Bring up the callback thread if it is not already up. |
| 224 | */ |
| 225 | int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt) |
| 226 | { |
| 227 | struct svc_serv *serv; |
| 228 | struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; |
| 229 | int ret; |
| 230 | struct net *net = xprt->xprt_net; |
| 231 | |
| 232 | mutex_lock(&nfs_callback_mutex); |
| 233 | |
| 234 | serv = nfs_callback_create_svc(minorversion); |
| 235 | if (IS_ERR(serv)) { |
| 236 | ret = PTR_ERR(serv); |
| 237 | goto err_create; |
| 238 | } |
| 239 | |
| 240 | ret = nfs_callback_up_net(minorversion, serv, net, xprt); |
| 241 | if (ret < 0) |
| 242 | goto err_net; |
| 243 | |
| 244 | ret = nfs_callback_start_svc(minorversion, xprt, serv); |
| 245 | if (ret < 0) |
| 246 | goto err_start; |
| 247 | |
| 248 | cb_info->users++; |
| 249 | err_net: |
| 250 | if (!cb_info->users) { |
| 251 | svc_set_num_threads(cb_info->serv, NULL, 0); |
| 252 | svc_destroy(&cb_info->serv); |
| 253 | } |
| 254 | err_create: |
| 255 | mutex_unlock(&nfs_callback_mutex); |
| 256 | return ret; |
| 257 | |
| 258 | err_start: |
| 259 | nfs_callback_down_net(minorversion, serv, net); |
| 260 | dprintk("NFS: Couldn't create server thread; err = %d\n", ret); |
| 261 | goto err_net; |
| 262 | } |
| 263 | |
| 264 | /* |
| 265 | * Kill the callback thread if it's no longer being used. |
| 266 | */ |
| 267 | void nfs_callback_down(int minorversion, struct net *net) |
| 268 | { |
| 269 | struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; |
| 270 | struct svc_serv *serv; |
| 271 | |
| 272 | mutex_lock(&nfs_callback_mutex); |
| 273 | serv = cb_info->serv; |
| 274 | nfs_callback_down_net(minorversion, serv, net); |
| 275 | cb_info->users--; |
| 276 | if (cb_info->users == 0) { |
| 277 | svc_set_num_threads(serv, NULL, 0); |
| 278 | dprintk("nfs_callback_down: service destroyed\n"); |
| 279 | svc_destroy(&cb_info->serv); |
| 280 | } |
| 281 | mutex_unlock(&nfs_callback_mutex); |
| 282 | } |
| 283 | |
| 284 | /* Boolean check of RPC_AUTH_GSS principal */ |
| 285 | int |
| 286 | check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp) |
| 287 | { |
| 288 | char *p = rqstp->rq_cred.cr_principal; |
| 289 | |
| 290 | if (rqstp->rq_authop->flavour != RPC_AUTH_GSS) |
| 291 | return 1; |
| 292 | |
| 293 | /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */ |
| 294 | if (clp->cl_minorversion != 0) |
| 295 | return 0; |
| 296 | /* |
| 297 | * It might just be a normal user principal, in which case |
| 298 | * userspace won't bother to tell us the name at all. |
| 299 | */ |
| 300 | if (p == NULL) |
| 301 | return 0; |
| 302 | |
| 303 | /* |
| 304 | * Did we get the acceptor from userland during the SETCLIENID |
| 305 | * negotiation? |
| 306 | */ |
| 307 | if (clp->cl_acceptor) |
| 308 | return !strcmp(p, clp->cl_acceptor); |
| 309 | |
| 310 | /* |
| 311 | * Otherwise try to verify it using the cl_hostname. Note that this |
| 312 | * doesn't work if a non-canonical hostname was used in the devname. |
| 313 | */ |
| 314 | |
| 315 | /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */ |
| 316 | |
| 317 | if (memcmp(p, "nfs@", 4) != 0) |
| 318 | return 0; |
| 319 | p += 4; |
| 320 | if (strcmp(p, clp->cl_hostname) != 0) |
| 321 | return 0; |
| 322 | return 1; |
| 323 | } |
| 324 | |
| 325 | /* |
| 326 | * pg_authenticate method for nfsv4 callback threads. |
| 327 | * |
| 328 | * The authflavor has been negotiated, so an incorrect flavor is a server |
| 329 | * bug. Deny packets with incorrect authflavor. |
| 330 | * |
| 331 | * All other checking done after NFS decoding where the nfs_client can be |
| 332 | * found in nfs4_callback_compound |
| 333 | */ |
| 334 | static enum svc_auth_status nfs_callback_authenticate(struct svc_rqst *rqstp) |
| 335 | { |
| 336 | rqstp->rq_auth_stat = rpc_autherr_badcred; |
| 337 | |
| 338 | switch (rqstp->rq_authop->flavour) { |
| 339 | case RPC_AUTH_NULL: |
| 340 | if (rqstp->rq_proc != CB_NULL) |
| 341 | return SVC_DENIED; |
| 342 | break; |
| 343 | case RPC_AUTH_GSS: |
| 344 | /* No RPC_AUTH_GSS support yet in NFSv4.1 */ |
| 345 | if (svc_is_backchannel(rqstp)) |
| 346 | return SVC_DENIED; |
| 347 | } |
| 348 | |
| 349 | rqstp->rq_auth_stat = rpc_auth_ok; |
| 350 | return SVC_OK; |
| 351 | } |
| 352 | |
| 353 | /* |
| 354 | * Define NFS4 callback program |
| 355 | */ |
| 356 | static const struct svc_version *nfs4_callback_version[] = { |
| 357 | [1] = &nfs4_callback_version1, |
| 358 | [4] = &nfs4_callback_version4, |
| 359 | }; |
| 360 | |
| 361 | static struct svc_program nfs4_callback_program = { |
| 362 | .pg_prog = NFS4_CALLBACK, /* RPC service number */ |
| 363 | .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */ |
| 364 | .pg_vers = nfs4_callback_version, /* version table */ |
| 365 | .pg_name = "NFSv4 callback", /* service name */ |
| 366 | .pg_class = "nfs", /* authentication class */ |
| 367 | .pg_authenticate = nfs_callback_authenticate, |
| 368 | .pg_init_request = svc_generic_init_request, |
| 369 | .pg_rpcbind_set = svc_generic_rpcbind_set, |
| 370 | }; |