1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/lockd/mon.c 4 * 5 * The kernel statd client. 6 * 7 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> 8 */ 9 10 #include <linux/types.h> 11 #include <linux/kernel.h> 12 #include <linux/ktime.h> 13 #include <linux/slab.h> 14 15 #include <linux/sunrpc/clnt.h> 16 #include <linux/sunrpc/addr.h> 17 #include <linux/sunrpc/xprtsock.h> 18 #include <linux/sunrpc/svc.h> 19 #include <linux/lockd/lockd.h> 20 21 #include <asm/unaligned.h> 22 23 #include "netns.h" 24 25 #define NLMDBG_FACILITY NLMDBG_MONITOR 26 #define NSM_PROGRAM 100024 27 #define NSM_VERSION 1 28 29 enum { 30 NSMPROC_NULL, 31 NSMPROC_STAT, 32 NSMPROC_MON, 33 NSMPROC_UNMON, 34 NSMPROC_UNMON_ALL, 35 NSMPROC_SIMU_CRASH, 36 NSMPROC_NOTIFY, 37 }; 38 39 struct nsm_args { 40 struct nsm_private *priv; 41 u32 prog; /* RPC callback info */ 42 u32 vers; 43 u32 proc; 44 45 char *mon_name; 46 const char *nodename; 47 }; 48 49 struct nsm_res { 50 u32 status; 51 u32 state; 52 }; 53 54 static const struct rpc_program nsm_program; 55 static DEFINE_SPINLOCK(nsm_lock); 56 57 /* 58 * Local NSM state 59 */ 60 u32 __read_mostly nsm_local_state; 61 bool __read_mostly nsm_use_hostnames; 62 63 static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm) 64 { 65 return (struct sockaddr *)&nsm->sm_addr; 66 } 67 68 static struct rpc_clnt *nsm_create(struct net *net, const char *nodename) 69 { 70 struct sockaddr_in sin = { 71 .sin_family = AF_INET, 72 .sin_addr.s_addr = htonl(INADDR_LOOPBACK), 73 }; 74 struct rpc_create_args args = { 75 .net = net, 76 .protocol = XPRT_TRANSPORT_TCP, 77 .address = (struct sockaddr *)&sin, 78 .addrsize = sizeof(sin), 79 .servername = "rpc.statd", 80 .nodename = nodename, 81 .program = &nsm_program, 82 .version = NSM_VERSION, 83 .authflavor = RPC_AUTH_NULL, 84 .flags = RPC_CLNT_CREATE_NOPING, 85 }; 86 87 return rpc_create(&args); 88 } 89 90 static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res, 91 const struct nlm_host *host) 92 { 93 int status; 94 struct rpc_clnt *clnt; 95 struct nsm_args args = { 96 .priv = &nsm->sm_priv, 97 .prog = NLM_PROGRAM, 98 .vers = 3, 99 .proc = NLMPROC_NSM_NOTIFY, 100 .mon_name = nsm->sm_mon_name, 101 .nodename = host->nodename, 102 }; 103 struct rpc_message msg = { 104 .rpc_argp = &args, 105 .rpc_resp = res, 106 }; 107 108 memset(res, 0, sizeof(*res)); 109 110 clnt = nsm_create(host->net, host->nodename); 111 if (IS_ERR(clnt)) { 112 dprintk("lockd: failed to create NSM upcall transport, " 113 "status=%ld, net=%x\n", PTR_ERR(clnt), 114 host->net->ns.inum); 115 return PTR_ERR(clnt); 116 } 117 118 msg.rpc_proc = &clnt->cl_procinfo[proc]; 119 status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN); 120 if (status == -ECONNREFUSED) { 121 dprintk("lockd: NSM upcall RPC failed, status=%d, forcing rebind\n", 122 status); 123 rpc_force_rebind(clnt); 124 status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN); 125 } 126 if (status < 0) 127 dprintk("lockd: NSM upcall RPC failed, status=%d\n", 128 status); 129 else 130 status = 0; 131 132 rpc_shutdown_client(clnt); 133 return status; 134 } 135 136 /** 137 * nsm_monitor - Notify a peer in case we reboot 138 * @host: pointer to nlm_host of peer to notify 139 * 140 * If this peer is not already monitored, this function sends an 141 * upcall to the local rpc.statd to record the name/address of 142 * the peer to notify in case we reboot. 143 * 144 * Returns zero if the peer is monitored by the local rpc.statd; 145 * otherwise a negative errno value is returned. 146 */ 147 int nsm_monitor(const struct nlm_host *host) 148 { 149 struct nsm_handle *nsm = host->h_nsmhandle; 150 struct nsm_res res; 151 int status; 152 153 dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name); 154 155 if (nsm->sm_monitored) 156 return 0; 157 158 /* 159 * Choose whether to record the caller_name or IP address of 160 * this peer in the local rpc.statd's database. 161 */ 162 nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf; 163 164 status = nsm_mon_unmon(nsm, NSMPROC_MON, &res, host); 165 if (unlikely(res.status != 0)) 166 status = -EIO; 167 if (unlikely(status < 0)) { 168 pr_notice_ratelimited("lockd: cannot monitor %s\n", nsm->sm_name); 169 return status; 170 } 171 172 nsm->sm_monitored = 1; 173 if (unlikely(nsm_local_state != res.state)) { 174 nsm_local_state = res.state; 175 dprintk("lockd: NSM state changed to %d\n", nsm_local_state); 176 } 177 return 0; 178 } 179 180 /** 181 * nsm_unmonitor - Unregister peer notification 182 * @host: pointer to nlm_host of peer to stop monitoring 183 * 184 * If this peer is monitored, this function sends an upcall to 185 * tell the local rpc.statd not to send this peer a notification 186 * when we reboot. 187 */ 188 void nsm_unmonitor(const struct nlm_host *host) 189 { 190 struct nsm_handle *nsm = host->h_nsmhandle; 191 struct nsm_res res; 192 int status; 193 194 if (atomic_read(&nsm->sm_count) == 1 195 && nsm->sm_monitored && !nsm->sm_sticky) { 196 dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name); 197 198 status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res, host); 199 if (res.status != 0) 200 status = -EIO; 201 if (status < 0) 202 printk(KERN_NOTICE "lockd: cannot unmonitor %s\n", 203 nsm->sm_name); 204 else 205 nsm->sm_monitored = 0; 206 } 207 } 208 209 static struct nsm_handle *nsm_lookup_hostname(const struct list_head *nsm_handles, 210 const char *hostname, const size_t len) 211 { 212 struct nsm_handle *nsm; 213 214 list_for_each_entry(nsm, nsm_handles, sm_link) 215 if (strlen(nsm->sm_name) == len && 216 memcmp(nsm->sm_name, hostname, len) == 0) 217 return nsm; 218 return NULL; 219 } 220 221 static struct nsm_handle *nsm_lookup_addr(const struct list_head *nsm_handles, 222 const struct sockaddr *sap) 223 { 224 struct nsm_handle *nsm; 225 226 list_for_each_entry(nsm, nsm_handles, sm_link) 227 if (rpc_cmp_addr(nsm_addr(nsm), sap)) 228 return nsm; 229 return NULL; 230 } 231 232 static struct nsm_handle *nsm_lookup_priv(const struct list_head *nsm_handles, 233 const struct nsm_private *priv) 234 { 235 struct nsm_handle *nsm; 236 237 list_for_each_entry(nsm, nsm_handles, sm_link) 238 if (memcmp(nsm->sm_priv.data, priv->data, 239 sizeof(priv->data)) == 0) 240 return nsm; 241 return NULL; 242 } 243 244 /* 245 * Construct a unique cookie to match this nsm_handle to this monitored 246 * host. It is passed to the local rpc.statd via NSMPROC_MON, and 247 * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these 248 * requests. 249 * 250 * The NSM protocol requires that these cookies be unique while the 251 * system is running. We prefer a stronger requirement of making them 252 * unique across reboots. If user space bugs cause a stale cookie to 253 * be sent to the kernel, it could cause the wrong host to lose its 254 * lock state if cookies were not unique across reboots. 255 * 256 * The cookies are exposed only to local user space via loopback. They 257 * do not appear on the physical network. If we want greater security 258 * for some reason, nsm_init_private() could perform a one-way hash to 259 * obscure the contents of the cookie. 260 */ 261 static void nsm_init_private(struct nsm_handle *nsm) 262 { 263 u64 *p = (u64 *)&nsm->sm_priv.data; 264 s64 ns; 265 266 ns = ktime_get_ns(); 267 put_unaligned(ns, p); 268 put_unaligned((unsigned long)nsm, p + 1); 269 } 270 271 static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap, 272 const size_t salen, 273 const char *hostname, 274 const size_t hostname_len) 275 { 276 struct nsm_handle *new; 277 278 new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL); 279 if (unlikely(new == NULL)) 280 return NULL; 281 282 atomic_set(&new->sm_count, 1); 283 new->sm_name = (char *)(new + 1); 284 memcpy(nsm_addr(new), sap, salen); 285 new->sm_addrlen = salen; 286 nsm_init_private(new); 287 288 if (rpc_ntop(nsm_addr(new), new->sm_addrbuf, 289 sizeof(new->sm_addrbuf)) == 0) 290 (void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf), 291 "unsupported address family"); 292 memcpy(new->sm_name, hostname, hostname_len); 293 new->sm_name[hostname_len] = '\0'; 294 295 return new; 296 } 297 298 /** 299 * nsm_get_handle - Find or create a cached nsm_handle 300 * @net: network namespace 301 * @sap: pointer to socket address of handle to find 302 * @salen: length of socket address 303 * @hostname: pointer to C string containing hostname to find 304 * @hostname_len: length of C string 305 * 306 * Behavior is modulated by the global nsm_use_hostnames variable. 307 * 308 * Returns a cached nsm_handle after bumping its ref count, or 309 * returns a fresh nsm_handle if a handle that matches @sap and/or 310 * @hostname cannot be found in the handle cache. Returns NULL if 311 * an error occurs. 312 */ 313 struct nsm_handle *nsm_get_handle(const struct net *net, 314 const struct sockaddr *sap, 315 const size_t salen, const char *hostname, 316 const size_t hostname_len) 317 { 318 struct nsm_handle *cached, *new = NULL; 319 struct lockd_net *ln = net_generic(net, lockd_net_id); 320 321 if (hostname && memchr(hostname, '/', hostname_len) != NULL) { 322 if (printk_ratelimit()) { 323 printk(KERN_WARNING "Invalid hostname \"%.*s\" " 324 "in NFS lock request\n", 325 (int)hostname_len, hostname); 326 } 327 return NULL; 328 } 329 330 retry: 331 spin_lock(&nsm_lock); 332 333 if (nsm_use_hostnames && hostname != NULL) 334 cached = nsm_lookup_hostname(&ln->nsm_handles, 335 hostname, hostname_len); 336 else 337 cached = nsm_lookup_addr(&ln->nsm_handles, sap); 338 339 if (cached != NULL) { 340 atomic_inc(&cached->sm_count); 341 spin_unlock(&nsm_lock); 342 kfree(new); 343 dprintk("lockd: found nsm_handle for %s (%s), " 344 "cnt %d\n", cached->sm_name, 345 cached->sm_addrbuf, 346 atomic_read(&cached->sm_count)); 347 return cached; 348 } 349 350 if (new != NULL) { 351 list_add(&new->sm_link, &ln->nsm_handles); 352 spin_unlock(&nsm_lock); 353 dprintk("lockd: created nsm_handle for %s (%s)\n", 354 new->sm_name, new->sm_addrbuf); 355 return new; 356 } 357 358 spin_unlock(&nsm_lock); 359 360 new = nsm_create_handle(sap, salen, hostname, hostname_len); 361 if (unlikely(new == NULL)) 362 return NULL; 363 goto retry; 364 } 365 366 /** 367 * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle 368 * @net: network namespace 369 * @info: pointer to NLMPROC_SM_NOTIFY arguments 370 * 371 * Returns a matching nsm_handle if found in the nsm cache. The returned 372 * nsm_handle's reference count is bumped. Otherwise returns NULL if some 373 * error occurred. 374 */ 375 struct nsm_handle *nsm_reboot_lookup(const struct net *net, 376 const struct nlm_reboot *info) 377 { 378 struct nsm_handle *cached; 379 struct lockd_net *ln = net_generic(net, lockd_net_id); 380 381 spin_lock(&nsm_lock); 382 383 cached = nsm_lookup_priv(&ln->nsm_handles, &info->priv); 384 if (unlikely(cached == NULL)) { 385 spin_unlock(&nsm_lock); 386 dprintk("lockd: never saw rebooted peer '%.*s' before\n", 387 info->len, info->mon); 388 return cached; 389 } 390 391 atomic_inc(&cached->sm_count); 392 spin_unlock(&nsm_lock); 393 394 dprintk("lockd: host %s (%s) rebooted, cnt %d\n", 395 cached->sm_name, cached->sm_addrbuf, 396 atomic_read(&cached->sm_count)); 397 return cached; 398 } 399 400 /** 401 * nsm_release - Release an NSM handle 402 * @nsm: pointer to handle to be released 403 * 404 */ 405 void nsm_release(struct nsm_handle *nsm) 406 { 407 if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) { 408 list_del(&nsm->sm_link); 409 spin_unlock(&nsm_lock); 410 dprintk("lockd: destroyed nsm_handle for %s (%s)\n", 411 nsm->sm_name, nsm->sm_addrbuf); 412 kfree(nsm); 413 } 414 } 415 416 /* 417 * XDR functions for NSM. 418 * 419 * See http://www.opengroup.org/ for details on the Network 420 * Status Monitor wire protocol. 421 */ 422 423 static void encode_nsm_string(struct xdr_stream *xdr, const char *string) 424 { 425 const u32 len = strlen(string); 426 __be32 *p; 427 428 p = xdr_reserve_space(xdr, 4 + len); 429 xdr_encode_opaque(p, string, len); 430 } 431 432 /* 433 * "mon_name" specifies the host to be monitored. 434 */ 435 static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp) 436 { 437 encode_nsm_string(xdr, argp->mon_name); 438 } 439 440 /* 441 * The "my_id" argument specifies the hostname and RPC procedure 442 * to be called when the status manager receives notification 443 * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name" 444 * has changed. 445 */ 446 static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp) 447 { 448 __be32 *p; 449 450 encode_nsm_string(xdr, argp->nodename); 451 p = xdr_reserve_space(xdr, 4 + 4 + 4); 452 *p++ = cpu_to_be32(argp->prog); 453 *p++ = cpu_to_be32(argp->vers); 454 *p = cpu_to_be32(argp->proc); 455 } 456 457 /* 458 * The "mon_id" argument specifies the non-private arguments 459 * of an NSMPROC_MON or NSMPROC_UNMON call. 460 */ 461 static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp) 462 { 463 encode_mon_name(xdr, argp); 464 encode_my_id(xdr, argp); 465 } 466 467 /* 468 * The "priv" argument may contain private information required 469 * by the NSMPROC_MON call. This information will be supplied in the 470 * NLMPROC_SM_NOTIFY call. 471 */ 472 static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp) 473 { 474 __be32 *p; 475 476 p = xdr_reserve_space(xdr, SM_PRIV_SIZE); 477 xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE); 478 } 479 480 static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr, 481 const void *argp) 482 { 483 encode_mon_id(xdr, argp); 484 encode_priv(xdr, argp); 485 } 486 487 static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr, 488 const void *argp) 489 { 490 encode_mon_id(xdr, argp); 491 } 492 493 static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp, 494 struct xdr_stream *xdr, 495 void *data) 496 { 497 struct nsm_res *resp = data; 498 __be32 *p; 499 500 p = xdr_inline_decode(xdr, 4 + 4); 501 if (unlikely(p == NULL)) 502 return -EIO; 503 resp->status = be32_to_cpup(p++); 504 resp->state = be32_to_cpup(p); 505 506 dprintk("lockd: %s status %d state %d\n", 507 __func__, resp->status, resp->state); 508 return 0; 509 } 510 511 static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp, 512 struct xdr_stream *xdr, 513 void *data) 514 { 515 struct nsm_res *resp = data; 516 __be32 *p; 517 518 p = xdr_inline_decode(xdr, 4); 519 if (unlikely(p == NULL)) 520 return -EIO; 521 resp->state = be32_to_cpup(p); 522 523 dprintk("lockd: %s state %d\n", __func__, resp->state); 524 return 0; 525 } 526 527 #define SM_my_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 528 #define SM_my_id_sz (SM_my_name_sz+3) 529 #define SM_mon_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 530 #define SM_mon_id_sz (SM_mon_name_sz+SM_my_id_sz) 531 #define SM_priv_sz (XDR_QUADLEN(SM_PRIV_SIZE)) 532 #define SM_mon_sz (SM_mon_id_sz+SM_priv_sz) 533 #define SM_monres_sz 2 534 #define SM_unmonres_sz 1 535 536 static const struct rpc_procinfo nsm_procedures[] = { 537 [NSMPROC_MON] = { 538 .p_proc = NSMPROC_MON, 539 .p_encode = nsm_xdr_enc_mon, 540 .p_decode = nsm_xdr_dec_stat_res, 541 .p_arglen = SM_mon_sz, 542 .p_replen = SM_monres_sz, 543 .p_statidx = NSMPROC_MON, 544 .p_name = "MONITOR", 545 }, 546 [NSMPROC_UNMON] = { 547 .p_proc = NSMPROC_UNMON, 548 .p_encode = nsm_xdr_enc_unmon, 549 .p_decode = nsm_xdr_dec_stat, 550 .p_arglen = SM_mon_id_sz, 551 .p_replen = SM_unmonres_sz, 552 .p_statidx = NSMPROC_UNMON, 553 .p_name = "UNMONITOR", 554 }, 555 }; 556 557 static unsigned int nsm_version1_counts[ARRAY_SIZE(nsm_procedures)]; 558 static const struct rpc_version nsm_version1 = { 559 .number = 1, 560 .nrprocs = ARRAY_SIZE(nsm_procedures), 561 .procs = nsm_procedures, 562 .counts = nsm_version1_counts, 563 }; 564 565 static const struct rpc_version *nsm_version[] = { 566 [1] = &nsm_version1, 567 }; 568 569 static struct rpc_stat nsm_stats; 570 571 static const struct rpc_program nsm_program = { 572 .name = "statd", 573 .number = NSM_PROGRAM, 574 .nrvers = ARRAY_SIZE(nsm_version), 575 .version = nsm_version, 576 .stats = &nsm_stats 577 }; 578