fs/lockd/mon.c

   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 };