fs/lockd/clntxdr.c

   1 /*
   2  * linux/fs/lockd/clntxdr.c
   3  *
   4  * XDR functions to encode/decode NLM version 3 RPC arguments and results.
   5  * NLM version 3 is backwards compatible with NLM versions 1 and 2.
   6  *
   7  * NLM client-side only.
   8  *
   9  * Copyright (C) 2010, Oracle.  All rights reserved.
  10  */
  11
  12 #include <linux/types.h>
  13 #include <linux/sunrpc/xdr.h>
  14 #include <linux/sunrpc/clnt.h>
  15 #include <linux/sunrpc/stats.h>
  16 #include <linux/lockd/lockd.h>
  17
  18 #define NLMDBG_FACILITY         NLMDBG_XDR
  19
  20 #if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)
  21 #  error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"
  22 #endif
  23
  24 /*
  25  * Declare the space requirements for NLM arguments and replies as
  26  * number of 32bit-words
  27  */
  28 #define NLM_cookie_sz           (1+(NLM_MAXCOOKIELEN>>2))
  29 #define NLM_caller_sz           (1+(NLMCLNT_OHSIZE>>2))
  30 #define NLM_owner_sz            (1+(NLMCLNT_OHSIZE>>2))
  31 #define NLM_fhandle_sz          (1+(NFS2_FHSIZE>>2))
  32 #define NLM_lock_sz             (3+NLM_caller_sz+NLM_owner_sz+NLM_fhandle_sz)
  33 #define NLM_holder_sz           (4+NLM_owner_sz)
  34
  35 #define NLM_testargs_sz         (NLM_cookie_sz+1+NLM_lock_sz)
  36 #define NLM_lockargs_sz         (NLM_cookie_sz+4+NLM_lock_sz)
  37 #define NLM_cancargs_sz         (NLM_cookie_sz+2+NLM_lock_sz)
  38 #define NLM_unlockargs_sz       (NLM_cookie_sz+NLM_lock_sz)
  39
  40 #define NLM_testres_sz          (NLM_cookie_sz+1+NLM_holder_sz)
  41 #define NLM_res_sz              (NLM_cookie_sz+1)
  42 #define NLM_norep_sz            (0)
  43
  44
  45 static s32 loff_t_to_s32(loff_t offset)
  46 {
  47         s32 res;
  48
  49         if (offset >= NLM_OFFSET_MAX)
  50                 res = NLM_OFFSET_MAX;
  51         else if (offset <= -NLM_OFFSET_MAX)
  52                 res = -NLM_OFFSET_MAX;
  53         else
  54                 res = offset;
  55         return res;
  56 }
  57
  58 static void nlm_compute_offsets(const struct nlm_lock *lock,
  59                                 u32 *l_offset, u32 *l_len)
  60 {
  61         const struct file_lock *fl = &lock->fl;
  62
  63         *l_offset = loff_t_to_s32(fl->fl_start);
  64         if (fl->fl_end == OFFSET_MAX)
  65                 *l_len = 0;
  66         else
  67                 *l_len = loff_t_to_s32(fl->fl_end - fl->fl_start + 1);
  68 }
  69
  70 /*
  71  * Handle decode buffer overflows out-of-line.
  72  */
  73 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
  74 {
  75         dprintk("lockd: %s prematurely hit the end of our receive buffer. "
  76                 "Remaining buffer length is %tu words.\n",
  77                 func, xdr->end - xdr->p);
  78 }
  79
  80
  81 /*
  82  * Encode/decode NLMv3 basic data types
  83  *
  84  * Basic NLMv3 data types are not defined in an IETF standards
  85  * document.  X/Open has a description of these data types that
  86  * is useful.  See Chapter 10 of "Protocols for Interworking:
  87  * XNFS, Version 3W".
  88  *
  89  * Not all basic data types have their own encoding and decoding
  90  * functions.  For run-time efficiency, some data types are encoded
  91  * or decoded inline.
  92  */
  93
  94 static void encode_bool(struct xdr_stream *xdr, const int value)
  95 {
  96         __be32 *p;
  97
  98         p = xdr_reserve_space(xdr, 4);
  99         *p = value ? xdr_one : xdr_zero;
 100 }
 101
 102 static void encode_int32(struct xdr_stream *xdr, const s32 value)
 103 {
 104         __be32 *p;
 105
 106         p = xdr_reserve_space(xdr, 4);
 107         *p = cpu_to_be32(value);
 108 }
 109
 110 /*
 111  *      typedef opaque netobj<MAXNETOBJ_SZ>
 112  */
 113 static void encode_netobj(struct xdr_stream *xdr,
 114                           const u8 *data, const unsigned int length)
 115 {
 116         __be32 *p;
 117
 118         p = xdr_reserve_space(xdr, 4 + length);
 119         xdr_encode_opaque(p, data, length);
 120 }
 121
 122 static int decode_netobj(struct xdr_stream *xdr,
 123                          struct xdr_netobj *obj)
 124 {
 125         u32 length;
 126         __be32 *p;
 127
 128         p = xdr_inline_decode(xdr, 4);
 129         if (unlikely(p == NULL))
 130                 goto out_overflow;
 131         length = be32_to_cpup(p++);
 132         if (unlikely(length > XDR_MAX_NETOBJ))
 133                 goto out_size;
 134         obj->len = length;
 135         obj->data = (u8 *)p;
 136         return 0;
 137 out_size:
 138         dprintk("NFS: returned netobj was too long: %u\n", length);
 139         return -EIO;
 140 out_overflow:
 141         print_overflow_msg(__func__, xdr);
 142         return -EIO;
 143 }
 144
 145 /*
 146  *      netobj cookie;
 147  */
 148 static void encode_cookie(struct xdr_stream *xdr,
 149                           const struct nlm_cookie *cookie)
 150 {
 151         encode_netobj(xdr, (u8 *)&cookie->data, cookie->len);
 152 }
 153
 154 static int decode_cookie(struct xdr_stream *xdr,
 155                          struct nlm_cookie *cookie)
 156 {
 157         u32 length;
 158         __be32 *p;
 159
 160         p = xdr_inline_decode(xdr, 4);
 161         if (unlikely(p == NULL))
 162                 goto out_overflow;
 163         length = be32_to_cpup(p++);
 164         /* apparently HPUX can return empty cookies */
 165         if (length == 0)
 166                 goto out_hpux;
 167         if (length > NLM_MAXCOOKIELEN)
 168                 goto out_size;
 169         p = xdr_inline_decode(xdr, length);
 170         if (unlikely(p == NULL))
 171                 goto out_overflow;
 172         cookie->len = length;
 173         memcpy(cookie->data, p, length);
 174         return 0;
 175 out_hpux:
 176         cookie->len = 4;
 177         memset(cookie->data, 0, 4);
 178         return 0;
 179 out_size:
 180         dprintk("NFS: returned cookie was too long: %u\n", length);
 181         return -EIO;
 182 out_overflow:
 183         print_overflow_msg(__func__, xdr);
 184         return -EIO;
 185 }
 186
 187 /*
 188  *      netobj fh;
 189  */
 190 static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh)
 191 {
 192         encode_netobj(xdr, (u8 *)&fh->data, NFS2_FHSIZE);
 193 }
 194
 195 /*
 196  *      enum nlm_stats {
 197  *              LCK_GRANTED = 0,
 198  *              LCK_DENIED = 1,
 199  *              LCK_DENIED_NOLOCKS = 2,
 200  *              LCK_BLOCKED = 3,
 201  *              LCK_DENIED_GRACE_PERIOD = 4
 202  *      };
 203  *
 204  *
 205  *      struct nlm_stat {
 206  *              nlm_stats stat;
 207  *      };
 208  *
 209  * NB: we don't swap bytes for the NLM status values.  The upper
 210  * layers deal directly with the status value in network byte
 211  * order.
 212  */
 213
 214 static void encode_nlm_stat(struct xdr_stream *xdr,
 215                             const __be32 stat)
 216 {
 217         __be32 *p;
 218
 219         WARN_ON_ONCE(be32_to_cpu(stat) > NLM_LCK_DENIED_GRACE_PERIOD);
 220         p = xdr_reserve_space(xdr, 4);
 221         *p = stat;
 222 }
 223
 224 static int decode_nlm_stat(struct xdr_stream *xdr,
 225                            __be32 *stat)
 226 {
 227         __be32 *p;
 228
 229         p = xdr_inline_decode(xdr, 4);
 230         if (unlikely(p == NULL))
 231                 goto out_overflow;
 232         if (unlikely(ntohl(*p) > ntohl(nlm_lck_denied_grace_period)))
 233                 goto out_enum;
 234         *stat = *p;
 235         return 0;
 236 out_enum:
 237         dprintk("%s: server returned invalid nlm_stats value: %u\n",
 238                 __func__, be32_to_cpup(p));
 239         return -EIO;
 240 out_overflow:
 241         print_overflow_msg(__func__, xdr);
 242         return -EIO;
 243 }
 244
 245 /*
 246  *      struct nlm_holder {
 247  *              bool exclusive;
 248  *              int uppid;
 249  *              netobj oh;
 250  *              unsigned l_offset;
 251  *              unsigned l_len;
 252  *      };
 253  */
 254 static void encode_nlm_holder(struct xdr_stream *xdr,
 255                               const struct nlm_res *result)
 256 {
 257         const struct nlm_lock *lock = &result->lock;
 258         u32 l_offset, l_len;
 259         __be32 *p;
 260
 261         encode_bool(xdr, lock->fl.fl_type == F_RDLCK);
 262         encode_int32(xdr, lock->svid);
 263         encode_netobj(xdr, lock->oh.data, lock->oh.len);
 264
 265         p = xdr_reserve_space(xdr, 4 + 4);
 266         nlm_compute_offsets(lock, &l_offset, &l_len);
 267         *p++ = cpu_to_be32(l_offset);
 268         *p   = cpu_to_be32(l_len);
 269 }
 270
 271 static int decode_nlm_holder(struct xdr_stream *xdr, struct nlm_res *result)
 272 {
 273         struct nlm_lock *lock = &result->lock;
 274         struct file_lock *fl = &lock->fl;
 275         u32 exclusive, l_offset, l_len;
 276         int error;
 277         __be32 *p;
 278         s32 end;
 279
 280         memset(lock, 0, sizeof(*lock));
 281         locks_init_lock(fl);
 282
 283         p = xdr_inline_decode(xdr, 4 + 4);
 284         if (unlikely(p == NULL))
 285                 goto out_overflow;
 286         exclusive = be32_to_cpup(p++);
 287         lock->svid = be32_to_cpup(p);
 288         fl->fl_pid = (pid_t)lock->svid;
 289
 290         error = decode_netobj(xdr, &lock->oh);
 291         if (unlikely(error))
 292                 goto out;
 293
 294         p = xdr_inline_decode(xdr, 4 + 4);
 295         if (unlikely(p == NULL))
 296                 goto out_overflow;
 297
 298         fl->fl_flags = FL_POSIX;
 299         fl->fl_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
 300         l_offset = be32_to_cpup(p++);
 301         l_len = be32_to_cpup(p);
 302         end = l_offset + l_len - 1;
 303
 304         fl->fl_start = (loff_t)l_offset;
 305         if (l_len == 0 || end < 0)
 306                 fl->fl_end = OFFSET_MAX;
 307         else
 308                 fl->fl_end = (loff_t)end;
 309         error = 0;
 310 out:
 311         return error;
 312 out_overflow:
 313         print_overflow_msg(__func__, xdr);
 314         return -EIO;
 315 }
 316
 317 /*
 318  *      string caller_name<LM_MAXSTRLEN>;
 319  */
 320 static void encode_caller_name(struct xdr_stream *xdr, const char *name)
 321 {
 322         /* NB: client-side does not set lock->len */
 323         u32 length = strlen(name);
 324         __be32 *p;
 325
 326         p = xdr_reserve_space(xdr, 4 + length);
 327         xdr_encode_opaque(p, name, length);
 328 }
 329
 330 /*
 331  *      struct nlm_lock {
 332  *              string caller_name<LM_MAXSTRLEN>;
 333  *              netobj fh;
 334  *              netobj oh;
 335  *              int uppid;
 336  *              unsigned l_offset;
 337  *              unsigned l_len;
 338  *      };
 339  */
 340 static void encode_nlm_lock(struct xdr_stream *xdr,
 341                             const struct nlm_lock *lock)
 342 {
 343         u32 l_offset, l_len;
 344         __be32 *p;
 345
 346         encode_caller_name(xdr, lock->caller);
 347         encode_fh(xdr, &lock->fh);
 348         encode_netobj(xdr, lock->oh.data, lock->oh.len);
 349
 350         p = xdr_reserve_space(xdr, 4 + 4 + 4);
 351         *p++ = cpu_to_be32(lock->svid);
 352
 353         nlm_compute_offsets(lock, &l_offset, &l_len);
 354         *p++ = cpu_to_be32(l_offset);
 355         *p   = cpu_to_be32(l_len);
 356 }
 357
 358
 359 /*
 360  * NLMv3 XDR encode functions
 361  *
 362  * NLMv3 argument types are defined in Chapter 10 of The Open Group's
 363  * "Protocols for Interworking: XNFS, Version 3W".
 364  */
 365
 366 /*
 367  *      struct nlm_testargs {
 368  *              netobj cookie;
 369  *              bool exclusive;
 370  *              struct nlm_lock alock;
 371  *      };
 372  */
 373 static void nlm_xdr_enc_testargs(struct rpc_rqst *req,
 374                                  struct xdr_stream *xdr,
 375                                  const struct nlm_args *args)
 376 {
 377         const struct nlm_lock *lock = &args->lock;
 378
 379         encode_cookie(xdr, &args->cookie);
 380         encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
 381         encode_nlm_lock(xdr, lock);
 382 }
 383
 384 /*
 385  *      struct nlm_lockargs {
 386  *              netobj cookie;
 387  *              bool block;
 388  *              bool exclusive;
 389  *              struct nlm_lock alock;
 390  *              bool reclaim;
 391  *              int state;
 392  *      };
 393  */
 394 static void nlm_xdr_enc_lockargs(struct rpc_rqst *req,
 395                                  struct xdr_stream *xdr,
 396                                  const struct nlm_args *args)
 397 {
 398         const struct nlm_lock *lock = &args->lock;
 399
 400         encode_cookie(xdr, &args->cookie);
 401         encode_bool(xdr, args->block);
 402         encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
 403         encode_nlm_lock(xdr, lock);
 404         encode_bool(xdr, args->reclaim);
 405         encode_int32(xdr, args->state);
 406 }
 407
 408 /*
 409  *      struct nlm_cancargs {
 410  *              netobj cookie;
 411  *              bool block;
 412  *              bool exclusive;
 413  *              struct nlm_lock alock;
 414  *      };
 415  */
 416 static void nlm_xdr_enc_cancargs(struct rpc_rqst *req,
 417                                  struct xdr_stream *xdr,
 418                                  const struct nlm_args *args)
 419 {
 420         const struct nlm_lock *lock = &args->lock;
 421
 422         encode_cookie(xdr, &args->cookie);
 423         encode_bool(xdr, args->block);
 424         encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
 425         encode_nlm_lock(xdr, lock);
 426 }
 427
 428 /*
 429  *      struct nlm_unlockargs {
 430  *              netobj cookie;
 431  *              struct nlm_lock alock;
 432  *      };
 433  */
 434 static void nlm_xdr_enc_unlockargs(struct rpc_rqst *req,
 435                                    struct xdr_stream *xdr,
 436                                    const struct nlm_args *args)
 437 {
 438         const struct nlm_lock *lock = &args->lock;
 439
 440         encode_cookie(xdr, &args->cookie);
 441         encode_nlm_lock(xdr, lock);
 442 }
 443
 444 /*
 445  *      struct nlm_res {
 446  *              netobj cookie;
 447  *              nlm_stat stat;
 448  *      };
 449  */
 450 static void nlm_xdr_enc_res(struct rpc_rqst *req,
 451                             struct xdr_stream *xdr,
 452                             const struct nlm_res *result)
 453 {
 454         encode_cookie(xdr, &result->cookie);
 455         encode_nlm_stat(xdr, result->status);
 456 }
 457
 458 /*
 459  *      union nlm_testrply switch (nlm_stats stat) {
 460  *      case LCK_DENIED:
 461  *              struct nlm_holder holder;
 462  *      default:
 463  *              void;
 464  *      };
 465  *
 466  *      struct nlm_testres {
 467  *              netobj cookie;
 468  *              nlm_testrply test_stat;
 469  *      };
 470  */
 471 static void encode_nlm_testrply(struct xdr_stream *xdr,
 472                                 const struct nlm_res *result)
 473 {
 474         if (result->status == nlm_lck_denied)
 475                 encode_nlm_holder(xdr, result);
 476 }
 477
 478 static void nlm_xdr_enc_testres(struct rpc_rqst *req,
 479                                 struct xdr_stream *xdr,
 480                                 const struct nlm_res *result)
 481 {
 482         encode_cookie(xdr, &result->cookie);
 483         encode_nlm_stat(xdr, result->status);
 484         encode_nlm_testrply(xdr, result);
 485 }
 486
 487
 488 /*
 489  * NLMv3 XDR decode functions
 490  *
 491  * NLMv3 result types are defined in Chapter 10 of The Open Group's
 492  * "Protocols for Interworking: XNFS, Version 3W".
 493  */
 494
 495 /*
 496  *      union nlm_testrply switch (nlm_stats stat) {
 497  *      case LCK_DENIED:
 498  *              struct nlm_holder holder;
 499  *      default:
 500  *              void;
 501  *      };
 502  *
 503  *      struct nlm_testres {
 504  *              netobj cookie;
 505  *              nlm_testrply test_stat;
 506  *      };
 507  */
 508 static int decode_nlm_testrply(struct xdr_stream *xdr,
 509                                struct nlm_res *result)
 510 {
 511         int error;
 512
 513         error = decode_nlm_stat(xdr, &result->status);
 514         if (unlikely(error))
 515                 goto out;
 516         if (result->status == nlm_lck_denied)
 517                 error = decode_nlm_holder(xdr, result);
 518 out:
 519         return error;
 520 }
 521
 522 static int nlm_xdr_dec_testres(struct rpc_rqst *req,
 523                                struct xdr_stream *xdr,
 524                                struct nlm_res *result)
 525 {
 526         int error;
 527
 528         error = decode_cookie(xdr, &result->cookie);
 529         if (unlikely(error))
 530                 goto out;
 531         error = decode_nlm_testrply(xdr, result);
 532 out:
 533         return error;
 534 }
 535
 536 /*
 537  *      struct nlm_res {
 538  *              netobj cookie;
 539  *              nlm_stat stat;
 540  *      };
 541  */
 542 static int nlm_xdr_dec_res(struct rpc_rqst *req,
 543                            struct xdr_stream *xdr,
 544                            struct nlm_res *result)
 545 {
 546         int error;
 547
 548         error = decode_cookie(xdr, &result->cookie);
 549         if (unlikely(error))
 550                 goto out;
 551         error = decode_nlm_stat(xdr, &result->status);
 552 out:
 553         return error;
 554 }
 555
 556
 557 /*
 558  * For NLM, a void procedure really returns nothing
 559  */
 560 #define nlm_xdr_dec_norep       NULL
 561
 562 #define PROC(proc, argtype, restype)    \
 563 [NLMPROC_##proc] = {                                                    \
 564         .p_proc      = NLMPROC_##proc,                                  \
 565         .p_encode    = (kxdreproc_t)nlm_xdr_enc_##argtype,              \
 566         .p_decode    = (kxdrdproc_t)nlm_xdr_dec_##restype,              \
 567         .p_arglen    = NLM_##argtype##_sz,                              \
 568         .p_replen    = NLM_##restype##_sz,                              \
 569         .p_statidx   = NLMPROC_##proc,                                  \
 570         .p_name      = #proc,                                           \
 571         }
 572
 573 static struct rpc_procinfo      nlm_procedures[] = {
 574         PROC(TEST,              testargs,       testres),
 575         PROC(LOCK,              lockargs,       res),
 576         PROC(CANCEL,            cancargs,       res),
 577         PROC(UNLOCK,            unlockargs,     res),
 578         PROC(GRANTED,           testargs,       res),
 579         PROC(TEST_MSG,          testargs,       norep),
 580         PROC(LOCK_MSG,          lockargs,       norep),
 581         PROC(CANCEL_MSG,        cancargs,       norep),
 582         PROC(UNLOCK_MSG,        unlockargs,     norep),
 583         PROC(GRANTED_MSG,       testargs,       norep),
 584         PROC(TEST_RES,          testres,        norep),
 585         PROC(LOCK_RES,          res,            norep),
 586         PROC(CANCEL_RES,        res,            norep),
 587         PROC(UNLOCK_RES,        res,            norep),
 588         PROC(GRANTED_RES,       res,            norep),
 589 };
 590
 591 static const struct rpc_version nlm_version1 = {
 592                 .number         = 1,
 593                 .nrprocs        = ARRAY_SIZE(nlm_procedures),
 594                 .procs          = nlm_procedures,
 595 };
 596
 597 static const struct rpc_version nlm_version3 = {
 598                 .number         = 3,
 599                 .nrprocs        = ARRAY_SIZE(nlm_procedures),
 600                 .procs          = nlm_procedures,
 601 };
 602
 603 static const struct rpc_version *nlm_versions[] = {
 604         [1] = &nlm_version1,
 605         [3] = &nlm_version3,
 606 #ifdef CONFIG_LOCKD_V4
 607         [4] = &nlm_version4,
 608 #endif
 609 };
 610
 611 static struct rpc_stat          nlm_rpc_stats;
 612
 613 const struct rpc_program        nlm_program = {
 614                 .name           = "lockd",
 615                 .number         = NLM_PROGRAM,
 616                 .nrvers         = ARRAY_SIZE(nlm_versions),
 617                 .version        = nlm_versions,
 618                 .stats          = &nlm_rpc_stats,
 619 };