1 /* 2 * linux/fs/nfs/callback.c 3 * 4 * Copyright (C) 2004 Trond Myklebust 5 * 6 * NFSv4 callback handling 7 */ 8 9 #include <linux/completion.h> 10 #include <linux/ip.h> 11 #include <linux/module.h> 12 #include <linux/smp_lock.h> 13 #include <linux/sunrpc/svc.h> 14 #include <linux/sunrpc/svcsock.h> 15 #include <linux/nfs_fs.h> 16 #include <linux/mutex.h> 17 #include <linux/freezer.h> 18 #include <linux/kthread.h> 19 #include <linux/sunrpc/svcauth_gss.h> 20 #if defined(CONFIG_NFS_V4_1) 21 #include <linux/sunrpc/bc_xprt.h> 22 #endif 23 24 #include <net/inet_sock.h> 25 26 #include "nfs4_fs.h" 27 #include "callback.h" 28 #include "internal.h" 29 30 #define NFSDBG_FACILITY NFSDBG_CALLBACK 31 32 struct nfs_callback_data { 33 unsigned int users; 34 struct svc_serv *serv; 35 struct svc_rqst *rqst; 36 struct task_struct *task; 37 }; 38 39 static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1]; 40 static DEFINE_MUTEX(nfs_callback_mutex); 41 static struct svc_program nfs4_callback_program; 42 43 unsigned int nfs_callback_set_tcpport; 44 unsigned short nfs_callback_tcpport; 45 unsigned short nfs_callback_tcpport6; 46 #define NFS_CALLBACK_MAXPORTNR (65535U) 47 48 static int param_set_portnr(const char *val, struct kernel_param *kp) 49 { 50 unsigned long num; 51 int ret; 52 53 if (!val) 54 return -EINVAL; 55 ret = strict_strtoul(val, 0, &num); 56 if (ret == -EINVAL || num > NFS_CALLBACK_MAXPORTNR) 57 return -EINVAL; 58 *((unsigned int *)kp->arg) = num; 59 return 0; 60 } 61 62 static int param_get_portnr(char *buffer, struct kernel_param *kp) 63 { 64 return param_get_uint(buffer, kp); 65 } 66 #define param_check_portnr(name, p) __param_check(name, p, unsigned int); 67 68 module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644); 69 70 /* 71 * This is the NFSv4 callback kernel thread. 72 */ 73 static int 74 nfs4_callback_svc(void *vrqstp) 75 { 76 int err, preverr = 0; 77 struct svc_rqst *rqstp = vrqstp; 78 79 set_freezable(); 80 81 while (!kthread_should_stop()) { 82 /* 83 * Listen for a request on the socket 84 */ 85 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT); 86 if (err == -EAGAIN || err == -EINTR) { 87 preverr = err; 88 continue; 89 } 90 if (err < 0) { 91 if (err != preverr) { 92 printk(KERN_WARNING "%s: unexpected error " 93 "from svc_recv (%d)\n", __func__, err); 94 preverr = err; 95 } 96 schedule_timeout_uninterruptible(HZ); 97 continue; 98 } 99 preverr = err; 100 svc_process(rqstp); 101 } 102 return 0; 103 } 104 105 /* 106 * Prepare to bring up the NFSv4 callback service 107 */ 108 struct svc_rqst * 109 nfs4_callback_up(struct svc_serv *serv) 110 { 111 int ret; 112 113 ret = svc_create_xprt(serv, "tcp", PF_INET, 114 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS); 115 if (ret <= 0) 116 goto out_err; 117 nfs_callback_tcpport = ret; 118 dprintk("NFS: Callback listener port = %u (af %u)\n", 119 nfs_callback_tcpport, PF_INET); 120 121 ret = svc_create_xprt(serv, "tcp", PF_INET6, 122 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS); 123 if (ret > 0) { 124 nfs_callback_tcpport6 = ret; 125 dprintk("NFS: Callback listener port = %u (af %u)\n", 126 nfs_callback_tcpport6, PF_INET6); 127 } else if (ret == -EAFNOSUPPORT) 128 ret = 0; 129 else 130 goto out_err; 131 132 return svc_prepare_thread(serv, &serv->sv_pools[0]); 133 134 out_err: 135 if (ret == 0) 136 ret = -ENOMEM; 137 return ERR_PTR(ret); 138 } 139 140 #if defined(CONFIG_NFS_V4_1) 141 /* 142 * The callback service for NFSv4.1 callbacks 143 */ 144 static int 145 nfs41_callback_svc(void *vrqstp) 146 { 147 struct svc_rqst *rqstp = vrqstp; 148 struct svc_serv *serv = rqstp->rq_server; 149 struct rpc_rqst *req; 150 int error; 151 DEFINE_WAIT(wq); 152 153 set_freezable(); 154 155 while (!kthread_should_stop()) { 156 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE); 157 spin_lock_bh(&serv->sv_cb_lock); 158 if (!list_empty(&serv->sv_cb_list)) { 159 req = list_first_entry(&serv->sv_cb_list, 160 struct rpc_rqst, rq_bc_list); 161 list_del(&req->rq_bc_list); 162 spin_unlock_bh(&serv->sv_cb_lock); 163 dprintk("Invoking bc_svc_process()\n"); 164 error = bc_svc_process(serv, req, rqstp); 165 dprintk("bc_svc_process() returned w/ error code= %d\n", 166 error); 167 } else { 168 spin_unlock_bh(&serv->sv_cb_lock); 169 schedule(); 170 } 171 finish_wait(&serv->sv_cb_waitq, &wq); 172 } 173 return 0; 174 } 175 176 /* 177 * Bring up the NFSv4.1 callback service 178 */ 179 struct svc_rqst * 180 nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt) 181 { 182 struct svc_xprt *bc_xprt; 183 struct svc_rqst *rqstp = ERR_PTR(-ENOMEM); 184 185 dprintk("--> %s\n", __func__); 186 /* Create a svc_sock for the service */ 187 bc_xprt = svc_sock_create(serv, xprt->prot); 188 if (!bc_xprt) 189 goto out; 190 191 /* 192 * Save the svc_serv in the transport so that it can 193 * be referenced when the session backchannel is initialized 194 */ 195 serv->bc_xprt = bc_xprt; 196 xprt->bc_serv = serv; 197 198 INIT_LIST_HEAD(&serv->sv_cb_list); 199 spin_lock_init(&serv->sv_cb_lock); 200 init_waitqueue_head(&serv->sv_cb_waitq); 201 rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]); 202 if (IS_ERR(rqstp)) 203 svc_sock_destroy(bc_xprt); 204 out: 205 dprintk("--> %s return %p\n", __func__, rqstp); 206 return rqstp; 207 } 208 209 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion, 210 struct svc_serv *serv, struct rpc_xprt *xprt, 211 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp)) 212 { 213 if (minorversion) { 214 *rqstpp = nfs41_callback_up(serv, xprt); 215 *callback_svc = nfs41_callback_svc; 216 } 217 return minorversion; 218 } 219 220 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, 221 struct nfs_callback_data *cb_info) 222 { 223 if (minorversion) 224 xprt->bc_serv = cb_info->serv; 225 } 226 #else 227 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion, 228 struct svc_serv *serv, struct rpc_xprt *xprt, 229 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp)) 230 { 231 return 0; 232 } 233 234 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, 235 struct nfs_callback_data *cb_info) 236 { 237 } 238 #endif /* CONFIG_NFS_V4_1 */ 239 240 /* 241 * Bring up the callback thread if it is not already up. 242 */ 243 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt) 244 { 245 struct svc_serv *serv = NULL; 246 struct svc_rqst *rqstp; 247 int (*callback_svc)(void *vrqstp); 248 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 249 char svc_name[12]; 250 int ret = 0; 251 int minorversion_setup; 252 253 mutex_lock(&nfs_callback_mutex); 254 if (cb_info->users++ || cb_info->task != NULL) { 255 nfs_callback_bc_serv(minorversion, xprt, cb_info); 256 goto out; 257 } 258 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL); 259 if (!serv) { 260 ret = -ENOMEM; 261 goto out_err; 262 } 263 264 minorversion_setup = nfs_minorversion_callback_svc_setup(minorversion, 265 serv, xprt, &rqstp, &callback_svc); 266 if (!minorversion_setup) { 267 /* v4.0 callback setup */ 268 rqstp = nfs4_callback_up(serv); 269 callback_svc = nfs4_callback_svc; 270 } 271 272 if (IS_ERR(rqstp)) { 273 ret = PTR_ERR(rqstp); 274 goto out_err; 275 } 276 277 svc_sock_update_bufs(serv); 278 279 sprintf(svc_name, "nfsv4.%u-svc", minorversion); 280 cb_info->serv = serv; 281 cb_info->rqst = rqstp; 282 cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name); 283 if (IS_ERR(cb_info->task)) { 284 ret = PTR_ERR(cb_info->task); 285 svc_exit_thread(cb_info->rqst); 286 cb_info->rqst = NULL; 287 cb_info->task = NULL; 288 goto out_err; 289 } 290 out: 291 /* 292 * svc_create creates the svc_serv with sv_nrthreads == 1, and then 293 * svc_prepare_thread increments that. So we need to call svc_destroy 294 * on both success and failure so that the refcount is 1 when the 295 * thread exits. 296 */ 297 if (serv) 298 svc_destroy(serv); 299 mutex_unlock(&nfs_callback_mutex); 300 return ret; 301 out_err: 302 dprintk("NFS: Couldn't create callback socket or server thread; " 303 "err = %d\n", ret); 304 cb_info->users--; 305 goto out; 306 } 307 308 /* 309 * Kill the callback thread if it's no longer being used. 310 */ 311 void nfs_callback_down(int minorversion) 312 { 313 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 314 315 mutex_lock(&nfs_callback_mutex); 316 cb_info->users--; 317 if (cb_info->users == 0 && cb_info->task != NULL) { 318 kthread_stop(cb_info->task); 319 svc_exit_thread(cb_info->rqst); 320 cb_info->serv = NULL; 321 cb_info->rqst = NULL; 322 cb_info->task = NULL; 323 } 324 mutex_unlock(&nfs_callback_mutex); 325 } 326 327 static int check_gss_callback_principal(struct nfs_client *clp, 328 struct svc_rqst *rqstp) 329 { 330 struct rpc_clnt *r = clp->cl_rpcclient; 331 char *p = svc_gss_principal(rqstp); 332 333 /* 334 * It might just be a normal user principal, in which case 335 * userspace won't bother to tell us the name at all. 336 */ 337 if (p == NULL) 338 return SVC_DENIED; 339 340 /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */ 341 342 if (memcmp(p, "nfs@", 4) != 0) 343 return SVC_DENIED; 344 p += 4; 345 if (strcmp(p, r->cl_server) != 0) 346 return SVC_DENIED; 347 return SVC_OK; 348 } 349 350 static int nfs_callback_authenticate(struct svc_rqst *rqstp) 351 { 352 struct nfs_client *clp; 353 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]); 354 int ret = SVC_OK; 355 356 /* Don't talk to strangers */ 357 clp = nfs_find_client(svc_addr(rqstp), 4); 358 if (clp == NULL) 359 return SVC_DROP; 360 361 dprintk("%s: %s NFSv4 callback!\n", __func__, 362 svc_print_addr(rqstp, buf, sizeof(buf))); 363 364 switch (rqstp->rq_authop->flavour) { 365 case RPC_AUTH_NULL: 366 if (rqstp->rq_proc != CB_NULL) 367 ret = SVC_DENIED; 368 break; 369 case RPC_AUTH_UNIX: 370 break; 371 case RPC_AUTH_GSS: 372 ret = check_gss_callback_principal(clp, rqstp); 373 break; 374 default: 375 ret = SVC_DENIED; 376 } 377 nfs_put_client(clp); 378 return ret; 379 } 380 381 /* 382 * Define NFS4 callback program 383 */ 384 static struct svc_version *nfs4_callback_version[] = { 385 [1] = &nfs4_callback_version1, 386 [4] = &nfs4_callback_version4, 387 }; 388 389 static struct svc_stat nfs4_callback_stats; 390 391 static struct svc_program nfs4_callback_program = { 392 .pg_prog = NFS4_CALLBACK, /* RPC service number */ 393 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */ 394 .pg_vers = nfs4_callback_version, /* version table */ 395 .pg_name = "NFSv4 callback", /* service name */ 396 .pg_class = "nfs", /* authentication class */ 397 .pg_stats = &nfs4_callback_stats, 398 .pg_authenticate = nfs_callback_authenticate, 399 }; 400