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