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 <linux/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 .cred = current_cred(), 86 }; 87 88 return rpc_create(&args); 89 } 90 91 static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res, 92 const struct nlm_host *host) 93 { 94 int status; 95 struct rpc_clnt *clnt; 96 struct nsm_args args = { 97 .priv = &nsm->sm_priv, 98 .prog = NLM_PROGRAM, 99 .vers = 3, 100 .proc = NLMPROC_NSM_NOTIFY, 101 .mon_name = nsm->sm_mon_name, 102 .nodename = host->nodename, 103 }; 104 struct rpc_message msg = { 105 .rpc_argp = &args, 106 .rpc_resp = res, 107 }; 108 109 memset(res, 0, sizeof(*res)); 110 111 clnt = nsm_create(host->net, host->nodename); 112 if (IS_ERR(clnt)) { 113 dprintk("lockd: failed to create NSM upcall transport, " 114 "status=%ld, net=%x\n", PTR_ERR(clnt), 115 host->net->ns.inum); 116 return PTR_ERR(clnt); 117 } 118 119 msg.rpc_proc = &clnt->cl_procinfo[proc]; 120 status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN); 121 if (status == -ECONNREFUSED) { 122 dprintk("lockd: NSM upcall RPC failed, status=%d, forcing rebind\n", 123 status); 124 rpc_force_rebind(clnt); 125 status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN); 126 } 127 if (status < 0) 128 dprintk("lockd: NSM upcall RPC failed, status=%d\n", 129 status); 130 else 131 status = 0; 132 133 rpc_shutdown_client(clnt); 134 return status; 135 } 136 137 /** 138 * nsm_monitor - Notify a peer in case we reboot 139 * @host: pointer to nlm_host of peer to notify 140 * 141 * If this peer is not already monitored, this function sends an 142 * upcall to the local rpc.statd to record the name/address of 143 * the peer to notify in case we reboot. 144 * 145 * Returns zero if the peer is monitored by the local rpc.statd; 146 * otherwise a negative errno value is returned. 147 */ 148 int nsm_monitor(const struct nlm_host *host) 149 { 150 struct nsm_handle *nsm = host->h_nsmhandle; 151 struct nsm_res res; 152 int status; 153 154 dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name); 155 156 if (nsm->sm_monitored) 157 return 0; 158 159 /* 160 * Choose whether to record the caller_name or IP address of 161 * this peer in the local rpc.statd's database. 162 */ 163 nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf; 164 165 status = nsm_mon_unmon(nsm, NSMPROC_MON, &res, host); 166 if (unlikely(res.status != 0)) 167 status = -EIO; 168 if (unlikely(status < 0)) { 169 pr_notice_ratelimited("lockd: cannot monitor %s\n", nsm->sm_name); 170 return status; 171 } 172 173 nsm->sm_monitored = 1; 174 if (unlikely(nsm_local_state != res.state)) { 175 nsm_local_state = res.state; 176 dprintk("lockd: NSM state changed to %d\n", nsm_local_state); 177 } 178 return 0; 179 } 180 181 /** 182 * nsm_unmonitor - Unregister peer notification 183 * @host: pointer to nlm_host of peer to stop monitoring 184 * 185 * If this peer is monitored, this function sends an upcall to 186 * tell the local rpc.statd not to send this peer a notification 187 * when we reboot. 188 */ 189 void nsm_unmonitor(const struct nlm_host *host) 190 { 191 struct nsm_handle *nsm = host->h_nsmhandle; 192 struct nsm_res res; 193 int status; 194 195 if (refcount_read(&nsm->sm_count) == 1 196 && nsm->sm_monitored && !nsm->sm_sticky) { 197 dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name); 198 199 status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res, host); 200 if (res.status != 0) 201 status = -EIO; 202 if (status < 0) 203 printk(KERN_NOTICE "lockd: cannot unmonitor %s\n", 204 nsm->sm_name); 205 else 206 nsm->sm_monitored = 0; 207 } 208 } 209 210 static struct nsm_handle *nsm_lookup_hostname(const struct list_head *nsm_handles, 211 const char *hostname, const size_t len) 212 { 213 struct nsm_handle *nsm; 214 215 list_for_each_entry(nsm, nsm_handles, sm_link) 216 if (strlen(nsm->sm_name) == len && 217 memcmp(nsm->sm_name, hostname, len) == 0) 218 return nsm; 219 return NULL; 220 } 221 222 static struct nsm_handle *nsm_lookup_addr(const struct list_head *nsm_handles, 223 const struct sockaddr *sap) 224 { 225 struct nsm_handle *nsm; 226 227 list_for_each_entry(nsm, nsm_handles, sm_link) 228 if (rpc_cmp_addr(nsm_addr(nsm), sap)) 229 return nsm; 230 return NULL; 231 } 232 233 static struct nsm_handle *nsm_lookup_priv(const struct list_head *nsm_handles, 234 const struct nsm_private *priv) 235 { 236 struct nsm_handle *nsm; 237 238 list_for_each_entry(nsm, nsm_handles, sm_link) 239 if (memcmp(nsm->sm_priv.data, priv->data, 240 sizeof(priv->data)) == 0) 241 return nsm; 242 return NULL; 243 } 244 245 /* 246 * Construct a unique cookie to match this nsm_handle to this monitored 247 * host. It is passed to the local rpc.statd via NSMPROC_MON, and 248 * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these 249 * requests. 250 * 251 * The NSM protocol requires that these cookies be unique while the 252 * system is running. We prefer a stronger requirement of making them 253 * unique across reboots. If user space bugs cause a stale cookie to 254 * be sent to the kernel, it could cause the wrong host to lose its 255 * lock state if cookies were not unique across reboots. 256 * 257 * The cookies are exposed only to local user space via loopback. They 258 * do not appear on the physical network. If we want greater security 259 * for some reason, nsm_init_private() could perform a one-way hash to 260 * obscure the contents of the cookie. 261 */ 262 static void nsm_init_private(struct nsm_handle *nsm) 263 { 264 u64 *p = (u64 *)&nsm->sm_priv.data; 265 s64 ns; 266 267 ns = ktime_get_ns(); 268 put_unaligned(ns, p); 269 put_unaligned((unsigned long)nsm, p + 1); 270 } 271 272 static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap, 273 const size_t salen, 274 const char *hostname, 275 const size_t hostname_len) 276 { 277 struct nsm_handle *new; 278 279 if (!hostname) 280 return NULL; 281 282 new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL); 283 if (unlikely(new == NULL)) 284 return NULL; 285 286 refcount_set(&new->sm_count, 1); 287 new->sm_name = (char *)(new + 1); 288 memcpy(nsm_addr(new), sap, salen); 289 new->sm_addrlen = salen; 290 nsm_init_private(new); 291 292 if (rpc_ntop(nsm_addr(new), new->sm_addrbuf, 293 sizeof(new->sm_addrbuf)) == 0) 294 (void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf), 295 "unsupported address family"); 296 memcpy(new->sm_name, hostname, hostname_len); 297 new->sm_name[hostname_len] = '\0'; 298 299 return new; 300 } 301 302 /** 303 * nsm_get_handle - Find or create a cached nsm_handle 304 * @net: network namespace 305 * @sap: pointer to socket address of handle to find 306 * @salen: length of socket address 307 * @hostname: pointer to C string containing hostname to find 308 * @hostname_len: length of C string 309 * 310 * Behavior is modulated by the global nsm_use_hostnames variable. 311 * 312 * Returns a cached nsm_handle after bumping its ref count, or 313 * returns a fresh nsm_handle if a handle that matches @sap and/or 314 * @hostname cannot be found in the handle cache. Returns NULL if 315 * an error occurs. 316 */ 317 struct nsm_handle *nsm_get_handle(const struct net *net, 318 const struct sockaddr *sap, 319 const size_t salen, const char *hostname, 320 const size_t hostname_len) 321 { 322 struct nsm_handle *cached, *new = NULL; 323 struct lockd_net *ln = net_generic(net, lockd_net_id); 324 325 if (hostname && memchr(hostname, '/', hostname_len) != NULL) { 326 if (printk_ratelimit()) { 327 printk(KERN_WARNING "Invalid hostname \"%.*s\" " 328 "in NFS lock request\n", 329 (int)hostname_len, hostname); 330 } 331 return NULL; 332 } 333 334 retry: 335 spin_lock(&nsm_lock); 336 337 if (nsm_use_hostnames && hostname != NULL) 338 cached = nsm_lookup_hostname(&ln->nsm_handles, 339 hostname, hostname_len); 340 else 341 cached = nsm_lookup_addr(&ln->nsm_handles, sap); 342 343 if (cached != NULL) { 344 refcount_inc(&cached->sm_count); 345 spin_unlock(&nsm_lock); 346 kfree(new); 347 dprintk("lockd: found nsm_handle for %s (%s), " 348 "cnt %d\n", cached->sm_name, 349 cached->sm_addrbuf, 350 refcount_read(&cached->sm_count)); 351 return cached; 352 } 353 354 if (new != NULL) { 355 list_add(&new->sm_link, &ln->nsm_handles); 356 spin_unlock(&nsm_lock); 357 dprintk("lockd: created nsm_handle for %s (%s)\n", 358 new->sm_name, new->sm_addrbuf); 359 return new; 360 } 361 362 spin_unlock(&nsm_lock); 363 364 new = nsm_create_handle(sap, salen, hostname, hostname_len); 365 if (unlikely(new == NULL)) 366 return NULL; 367 goto retry; 368 } 369 370 /** 371 * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle 372 * @net: network namespace 373 * @info: pointer to NLMPROC_SM_NOTIFY arguments 374 * 375 * Returns a matching nsm_handle if found in the nsm cache. The returned 376 * nsm_handle's reference count is bumped. Otherwise returns NULL if some 377 * error occurred. 378 */ 379 struct nsm_handle *nsm_reboot_lookup(const struct net *net, 380 const struct nlm_reboot *info) 381 { 382 struct nsm_handle *cached; 383 struct lockd_net *ln = net_generic(net, lockd_net_id); 384 385 spin_lock(&nsm_lock); 386 387 cached = nsm_lookup_priv(&ln->nsm_handles, &info->priv); 388 if (unlikely(cached == NULL)) { 389 spin_unlock(&nsm_lock); 390 dprintk("lockd: never saw rebooted peer '%.*s' before\n", 391 info->len, info->mon); 392 return cached; 393 } 394 395 refcount_inc(&cached->sm_count); 396 spin_unlock(&nsm_lock); 397 398 dprintk("lockd: host %s (%s) rebooted, cnt %d\n", 399 cached->sm_name, cached->sm_addrbuf, 400 refcount_read(&cached->sm_count)); 401 return cached; 402 } 403 404 /** 405 * nsm_release - Release an NSM handle 406 * @nsm: pointer to handle to be released 407 * 408 */ 409 void nsm_release(struct nsm_handle *nsm) 410 { 411 if (refcount_dec_and_lock(&nsm->sm_count, &nsm_lock)) { 412 list_del(&nsm->sm_link); 413 spin_unlock(&nsm_lock); 414 dprintk("lockd: destroyed nsm_handle for %s (%s)\n", 415 nsm->sm_name, nsm->sm_addrbuf); 416 kfree(nsm); 417 } 418 } 419 420 /* 421 * XDR functions for NSM. 422 * 423 * See https://www.opengroup.org/ for details on the Network 424 * Status Monitor wire protocol. 425 */ 426 427 static void encode_nsm_string(struct xdr_stream *xdr, const char *string) 428 { 429 const u32 len = strlen(string); 430 __be32 *p; 431 432 p = xdr_reserve_space(xdr, 4 + len); 433 xdr_encode_opaque(p, string, len); 434 } 435 436 /* 437 * "mon_name" specifies the host to be monitored. 438 */ 439 static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp) 440 { 441 encode_nsm_string(xdr, argp->mon_name); 442 } 443 444 /* 445 * The "my_id" argument specifies the hostname and RPC procedure 446 * to be called when the status manager receives notification 447 * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name" 448 * has changed. 449 */ 450 static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp) 451 { 452 __be32 *p; 453 454 encode_nsm_string(xdr, argp->nodename); 455 p = xdr_reserve_space(xdr, 4 + 4 + 4); 456 *p++ = cpu_to_be32(argp->prog); 457 *p++ = cpu_to_be32(argp->vers); 458 *p = cpu_to_be32(argp->proc); 459 } 460 461 /* 462 * The "mon_id" argument specifies the non-private arguments 463 * of an NSMPROC_MON or NSMPROC_UNMON call. 464 */ 465 static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp) 466 { 467 encode_mon_name(xdr, argp); 468 encode_my_id(xdr, argp); 469 } 470 471 /* 472 * The "priv" argument may contain private information required 473 * by the NSMPROC_MON call. This information will be supplied in the 474 * NLMPROC_SM_NOTIFY call. 475 */ 476 static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp) 477 { 478 __be32 *p; 479 480 p = xdr_reserve_space(xdr, SM_PRIV_SIZE); 481 xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE); 482 } 483 484 static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr, 485 const void *argp) 486 { 487 encode_mon_id(xdr, argp); 488 encode_priv(xdr, argp); 489 } 490 491 static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr, 492 const void *argp) 493 { 494 encode_mon_id(xdr, argp); 495 } 496 497 static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp, 498 struct xdr_stream *xdr, 499 void *data) 500 { 501 struct nsm_res *resp = data; 502 __be32 *p; 503 504 p = xdr_inline_decode(xdr, 4 + 4); 505 if (unlikely(p == NULL)) 506 return -EIO; 507 resp->status = be32_to_cpup(p++); 508 resp->state = be32_to_cpup(p); 509 510 dprintk("lockd: %s status %d state %d\n", 511 __func__, resp->status, resp->state); 512 return 0; 513 } 514 515 static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp, 516 struct xdr_stream *xdr, 517 void *data) 518 { 519 struct nsm_res *resp = data; 520 __be32 *p; 521 522 p = xdr_inline_decode(xdr, 4); 523 if (unlikely(p == NULL)) 524 return -EIO; 525 resp->state = be32_to_cpup(p); 526 527 dprintk("lockd: %s state %d\n", __func__, resp->state); 528 return 0; 529 } 530 531 #define SM_my_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 532 #define SM_my_id_sz (SM_my_name_sz+3) 533 #define SM_mon_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 534 #define SM_mon_id_sz (SM_mon_name_sz+SM_my_id_sz) 535 #define SM_priv_sz (XDR_QUADLEN(SM_PRIV_SIZE)) 536 #define SM_mon_sz (SM_mon_id_sz+SM_priv_sz) 537 #define SM_monres_sz 2 538 #define SM_unmonres_sz 1 539 540 static const struct rpc_procinfo nsm_procedures[] = { 541 [NSMPROC_MON] = { 542 .p_proc = NSMPROC_MON, 543 .p_encode = nsm_xdr_enc_mon, 544 .p_decode = nsm_xdr_dec_stat_res, 545 .p_arglen = SM_mon_sz, 546 .p_replen = SM_monres_sz, 547 .p_statidx = NSMPROC_MON, 548 .p_name = "MONITOR", 549 }, 550 [NSMPROC_UNMON] = { 551 .p_proc = NSMPROC_UNMON, 552 .p_encode = nsm_xdr_enc_unmon, 553 .p_decode = nsm_xdr_dec_stat, 554 .p_arglen = SM_mon_id_sz, 555 .p_replen = SM_unmonres_sz, 556 .p_statidx = NSMPROC_UNMON, 557 .p_name = "UNMONITOR", 558 }, 559 }; 560 561 static unsigned int nsm_version1_counts[ARRAY_SIZE(nsm_procedures)]; 562 static const struct rpc_version nsm_version1 = { 563 .number = 1, 564 .nrprocs = ARRAY_SIZE(nsm_procedures), 565 .procs = nsm_procedures, 566 .counts = nsm_version1_counts, 567 }; 568 569 static const struct rpc_version *nsm_version[] = { 570 [1] = &nsm_version1, 571 }; 572 573 static struct rpc_stat nsm_stats; 574 575 static const struct rpc_program nsm_program = { 576 .name = "statd", 577 .number = NSM_PROGRAM, 578 .nrvers = ARRAY_SIZE(nsm_version), 579 .version = nsm_version, 580 .stats = &nsm_stats 581 }; 582