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 .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 new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL); 280 if (unlikely(new == NULL)) 281 return NULL; 282 283 refcount_set(&new->sm_count, 1); 284 new->sm_name = (char *)(new + 1); 285 memcpy(nsm_addr(new), sap, salen); 286 new->sm_addrlen = salen; 287 nsm_init_private(new); 288 289 if (rpc_ntop(nsm_addr(new), new->sm_addrbuf, 290 sizeof(new->sm_addrbuf)) == 0) 291 (void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf), 292 "unsupported address family"); 293 memcpy(new->sm_name, hostname, hostname_len); 294 new->sm_name[hostname_len] = '\0'; 295 296 return new; 297 } 298 299 /** 300 * nsm_get_handle - Find or create a cached nsm_handle 301 * @net: network namespace 302 * @sap: pointer to socket address of handle to find 303 * @salen: length of socket address 304 * @hostname: pointer to C string containing hostname to find 305 * @hostname_len: length of C string 306 * 307 * Behavior is modulated by the global nsm_use_hostnames variable. 308 * 309 * Returns a cached nsm_handle after bumping its ref count, or 310 * returns a fresh nsm_handle if a handle that matches @sap and/or 311 * @hostname cannot be found in the handle cache. Returns NULL if 312 * an error occurs. 313 */ 314 struct nsm_handle *nsm_get_handle(const struct net *net, 315 const struct sockaddr *sap, 316 const size_t salen, const char *hostname, 317 const size_t hostname_len) 318 { 319 struct nsm_handle *cached, *new = NULL; 320 struct lockd_net *ln = net_generic(net, lockd_net_id); 321 322 if (hostname && memchr(hostname, '/', hostname_len) != NULL) { 323 if (printk_ratelimit()) { 324 printk(KERN_WARNING "Invalid hostname \"%.*s\" " 325 "in NFS lock request\n", 326 (int)hostname_len, hostname); 327 } 328 return NULL; 329 } 330 331 retry: 332 spin_lock(&nsm_lock); 333 334 if (nsm_use_hostnames && hostname != NULL) 335 cached = nsm_lookup_hostname(&ln->nsm_handles, 336 hostname, hostname_len); 337 else 338 cached = nsm_lookup_addr(&ln->nsm_handles, sap); 339 340 if (cached != NULL) { 341 refcount_inc(&cached->sm_count); 342 spin_unlock(&nsm_lock); 343 kfree(new); 344 dprintk("lockd: found nsm_handle for %s (%s), " 345 "cnt %d\n", cached->sm_name, 346 cached->sm_addrbuf, 347 refcount_read(&cached->sm_count)); 348 return cached; 349 } 350 351 if (new != NULL) { 352 list_add(&new->sm_link, &ln->nsm_handles); 353 spin_unlock(&nsm_lock); 354 dprintk("lockd: created nsm_handle for %s (%s)\n", 355 new->sm_name, new->sm_addrbuf); 356 return new; 357 } 358 359 spin_unlock(&nsm_lock); 360 361 new = nsm_create_handle(sap, salen, hostname, hostname_len); 362 if (unlikely(new == NULL)) 363 return NULL; 364 goto retry; 365 } 366 367 /** 368 * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle 369 * @net: network namespace 370 * @info: pointer to NLMPROC_SM_NOTIFY arguments 371 * 372 * Returns a matching nsm_handle if found in the nsm cache. The returned 373 * nsm_handle's reference count is bumped. Otherwise returns NULL if some 374 * error occurred. 375 */ 376 struct nsm_handle *nsm_reboot_lookup(const struct net *net, 377 const struct nlm_reboot *info) 378 { 379 struct nsm_handle *cached; 380 struct lockd_net *ln = net_generic(net, lockd_net_id); 381 382 spin_lock(&nsm_lock); 383 384 cached = nsm_lookup_priv(&ln->nsm_handles, &info->priv); 385 if (unlikely(cached == NULL)) { 386 spin_unlock(&nsm_lock); 387 dprintk("lockd: never saw rebooted peer '%.*s' before\n", 388 info->len, info->mon); 389 return cached; 390 } 391 392 refcount_inc(&cached->sm_count); 393 spin_unlock(&nsm_lock); 394 395 dprintk("lockd: host %s (%s) rebooted, cnt %d\n", 396 cached->sm_name, cached->sm_addrbuf, 397 refcount_read(&cached->sm_count)); 398 return cached; 399 } 400 401 /** 402 * nsm_release - Release an NSM handle 403 * @nsm: pointer to handle to be released 404 * 405 */ 406 void nsm_release(struct nsm_handle *nsm) 407 { 408 if (refcount_dec_and_lock(&nsm->sm_count, &nsm_lock)) { 409 list_del(&nsm->sm_link); 410 spin_unlock(&nsm_lock); 411 dprintk("lockd: destroyed nsm_handle for %s (%s)\n", 412 nsm->sm_name, nsm->sm_addrbuf); 413 kfree(nsm); 414 } 415 } 416 417 /* 418 * XDR functions for NSM. 419 * 420 * See http://www.opengroup.org/ for details on the Network 421 * Status Monitor wire protocol. 422 */ 423 424 static void encode_nsm_string(struct xdr_stream *xdr, const char *string) 425 { 426 const u32 len = strlen(string); 427 __be32 *p; 428 429 p = xdr_reserve_space(xdr, 4 + len); 430 xdr_encode_opaque(p, string, len); 431 } 432 433 /* 434 * "mon_name" specifies the host to be monitored. 435 */ 436 static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp) 437 { 438 encode_nsm_string(xdr, argp->mon_name); 439 } 440 441 /* 442 * The "my_id" argument specifies the hostname and RPC procedure 443 * to be called when the status manager receives notification 444 * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name" 445 * has changed. 446 */ 447 static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp) 448 { 449 __be32 *p; 450 451 encode_nsm_string(xdr, argp->nodename); 452 p = xdr_reserve_space(xdr, 4 + 4 + 4); 453 *p++ = cpu_to_be32(argp->prog); 454 *p++ = cpu_to_be32(argp->vers); 455 *p = cpu_to_be32(argp->proc); 456 } 457 458 /* 459 * The "mon_id" argument specifies the non-private arguments 460 * of an NSMPROC_MON or NSMPROC_UNMON call. 461 */ 462 static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp) 463 { 464 encode_mon_name(xdr, argp); 465 encode_my_id(xdr, argp); 466 } 467 468 /* 469 * The "priv" argument may contain private information required 470 * by the NSMPROC_MON call. This information will be supplied in the 471 * NLMPROC_SM_NOTIFY call. 472 */ 473 static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp) 474 { 475 __be32 *p; 476 477 p = xdr_reserve_space(xdr, SM_PRIV_SIZE); 478 xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE); 479 } 480 481 static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr, 482 const void *argp) 483 { 484 encode_mon_id(xdr, argp); 485 encode_priv(xdr, argp); 486 } 487 488 static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr, 489 const void *argp) 490 { 491 encode_mon_id(xdr, argp); 492 } 493 494 static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp, 495 struct xdr_stream *xdr, 496 void *data) 497 { 498 struct nsm_res *resp = data; 499 __be32 *p; 500 501 p = xdr_inline_decode(xdr, 4 + 4); 502 if (unlikely(p == NULL)) 503 return -EIO; 504 resp->status = be32_to_cpup(p++); 505 resp->state = be32_to_cpup(p); 506 507 dprintk("lockd: %s status %d state %d\n", 508 __func__, resp->status, resp->state); 509 return 0; 510 } 511 512 static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp, 513 struct xdr_stream *xdr, 514 void *data) 515 { 516 struct nsm_res *resp = data; 517 __be32 *p; 518 519 p = xdr_inline_decode(xdr, 4); 520 if (unlikely(p == NULL)) 521 return -EIO; 522 resp->state = be32_to_cpup(p); 523 524 dprintk("lockd: %s state %d\n", __func__, resp->state); 525 return 0; 526 } 527 528 #define SM_my_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 529 #define SM_my_id_sz (SM_my_name_sz+3) 530 #define SM_mon_name_sz (1+XDR_QUADLEN(SM_MAXSTRLEN)) 531 #define SM_mon_id_sz (SM_mon_name_sz+SM_my_id_sz) 532 #define SM_priv_sz (XDR_QUADLEN(SM_PRIV_SIZE)) 533 #define SM_mon_sz (SM_mon_id_sz+SM_priv_sz) 534 #define SM_monres_sz 2 535 #define SM_unmonres_sz 1 536 537 static const struct rpc_procinfo nsm_procedures[] = { 538 [NSMPROC_MON] = { 539 .p_proc = NSMPROC_MON, 540 .p_encode = nsm_xdr_enc_mon, 541 .p_decode = nsm_xdr_dec_stat_res, 542 .p_arglen = SM_mon_sz, 543 .p_replen = SM_monres_sz, 544 .p_statidx = NSMPROC_MON, 545 .p_name = "MONITOR", 546 }, 547 [NSMPROC_UNMON] = { 548 .p_proc = NSMPROC_UNMON, 549 .p_encode = nsm_xdr_enc_unmon, 550 .p_decode = nsm_xdr_dec_stat, 551 .p_arglen = SM_mon_id_sz, 552 .p_replen = SM_unmonres_sz, 553 .p_statidx = NSMPROC_UNMON, 554 .p_name = "UNMONITOR", 555 }, 556 }; 557 558 static unsigned int nsm_version1_counts[ARRAY_SIZE(nsm_procedures)]; 559 static const struct rpc_version nsm_version1 = { 560 .number = 1, 561 .nrprocs = ARRAY_SIZE(nsm_procedures), 562 .procs = nsm_procedures, 563 .counts = nsm_version1_counts, 564 }; 565 566 static const struct rpc_version *nsm_version[] = { 567 [1] = &nsm_version1, 568 }; 569 570 static struct rpc_stat nsm_stats; 571 572 static const struct rpc_program nsm_program = { 573 .name = "statd", 574 .number = NSM_PROGRAM, 575 .nrvers = ARRAY_SIZE(nsm_version), 576 .version = nsm_version, 577 .stats = &nsm_stats 578 }; 579