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 #include <uapi/linux/nfs2.h>
  19
  20 #define NLMDBG_FACILITY         NLMDBG_XDR
  21
  22 #if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)
  23 #  error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"
  24 #endif
  25
  26 /*
  27  * Declare the space requirements for NLM arguments and replies as
  28  * number of 32bit-words
  29  */
  30 #define NLM_cookie_sz           (1+(NLM_MAXCOOKIELEN>>2))
  31 #define NLM_caller_sz           (1+(NLMCLNT_OHSIZE>>2))
  32 #define NLM_owner_sz            (1+(NLMCLNT_OHSIZE>>2))
  33 #define NLM_fhandle_sz          (1+(NFS2_FHSIZE>>2))
  34 #define NLM_lock_sz             (3+NLM_caller_sz+NLM_owner_sz+NLM_fhandle_sz)
  35 #define NLM_holder_sz           (4+NLM_owner_sz)
  36
  37 #define NLM_testargs_sz         (NLM_cookie_sz+1+NLM_lock_sz)
  38 #define NLM_lockargs_sz         (NLM_cookie_sz+4+NLM_lock_sz)
  39 #define NLM_cancargs_sz         (NLM_cookie_sz+2+NLM_lock_sz)
  40 #define NLM_unlockargs_sz       (NLM_cookie_sz+NLM_lock_sz)
  41
  42 #define NLM_testres_sz          (NLM_cookie_sz+1+NLM_holder_sz)
  43 #define NLM_res_sz              (NLM_cookie_sz+1)
  44 #define NLM_norep_sz            (0)
  45
  46
  47 static s32 loff_t_to_s32(loff_t offset)
  48 {
  49         s32 res;
  50
  51         if (offset >= NLM_OFFSET_MAX)
  52                 res = NLM_OFFSET_MAX;
  53         else if (offset <= -NLM_OFFSET_MAX)
  54                 res = -NLM_OFFSET_MAX;
  55         else
  56                 res = offset;
  57         return res;
  58 }
  59
  60 static void nlm_compute_offsets(const struct nlm_lock *lock,
  61                                 u32 *l_offset, u32 *l_len)
  62 {
  63         const struct file_lock *fl = &lock->fl;
  64
  65         *l_offset = loff_t_to_s32(fl->fl_start);
  66         if (fl->fl_end == OFFSET_MAX)
  67                 *l_len = 0;
  68         else
  69                 *l_len = loff_t_to_s32(fl->fl_end - fl->fl_start + 1);
  70 }
  71
  72 /*
  73  * Handle decode buffer overflows out-of-line.
  74  */
  75 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
  76 {
  77         dprintk("lockd: %s prematurely hit the end of our receive buffer. "
  78                 "Remaining buffer length is %tu words.\n",
  79                 func, xdr->end - xdr->p);
  80 }
  81
  82
  83 /*
  84  * Encode/decode NLMv3 basic data types
  85  *
  86  * Basic NLMv3 data types are not defined in an IETF standards
  87  * document.  X/Open has a description of these data types that
  88  * is useful.  See Chapter 10 of "Protocols for Interworking:
  89  * XNFS, Version 3W".
  90  *
  91  * Not all basic data types have their own encoding and decoding
  92  * functions.  For run-time efficiency, some data types are encoded
  93  * or decoded inline.
  94  */
  95
  96 static void encode_bool(struct xdr_stream *xdr, const int value)
  97 {
  98         __be32 *p;
  99
 100         p = xdr_reserve_space(xdr, 4);
 101         *p = value ? xdr_one : xdr_zero;
 102 }
 103
 104 static void encode_int32(struct xdr_stream *xdr, const s32 value)
 105 {
 106         __be32 *p;
 107
 108         p = xdr_reserve_space(xdr, 4);
 109         *p = cpu_to_be32(value);
 110 }
 111
 112 /*
 113  *      typedef opaque netobj<MAXNETOBJ_SZ>
 114  */
 115 static void encode_netobj(struct xdr_stream *xdr,
 116                           const u8 *data, const unsigned int length)
 117 {
 118         __be32 *p;
 119
 120         p = xdr_reserve_space(xdr, 4 + length);
 121         xdr_encode_opaque(p, data, length);
 122 }
 123
 124 static int decode_netobj(struct xdr_stream *xdr,
 125                          struct xdr_netobj *obj)
 126 {
 127         u32 length;
 128         __be32 *p;
 129
 130         p = xdr_inline_decode(xdr, 4);
 131         if (unlikely(p == NULL))
 132                 goto out_overflow;
 133         length = be32_to_cpup(p++);
 134         if (unlikely(length > XDR_MAX_NETOBJ))
 135                 goto out_size;
 136         obj->len = length;
 137         obj->data = (u8 *)p;
 138         return 0;
 139 out_size:
 140         dprintk("NFS: returned netobj was too long: %u\n", length);
 141         return -EIO;
 142 out_overflow:
 143         print_overflow_msg(__func__, xdr);
 144         return -EIO;
 145 }
 146
 147 /*
 148  *      netobj cookie;
 149  */
 150 static void encode_cookie(struct xdr_stream *xdr,
 151                           const struct nlm_cookie *cookie)
 152 {
 153         encode_netobj(xdr, (u8 *)&cookie->data, cookie->len);
 154 }
 155
 156 static int decode_cookie(struct xdr_stream *xdr,
 157                          struct nlm_cookie *cookie)
 158 {
 159         u32 length;
 160         __be32 *p;
 161
 162         p = xdr_inline_decode(xdr, 4);
 163         if (unlikely(p == NULL))
 164                 goto out_overflow;
 165         length = be32_to_cpup(p++);
 166         /* apparently HPUX can return empty cookies */
 167         if (length == 0)
 168                 goto out_hpux;
 169         if (length > NLM_MAXCOOKIELEN)
 170                 goto out_size;
 171         p = xdr_inline_decode(xdr, length);
 172         if (unlikely(p == NULL))
 173                 goto out_overflow;
 174         cookie->len = length;
 175         memcpy(cookie->data, p, length);
 176         return 0;
 177 out_hpux:
 178         cookie->len = 4;
 179         memset(cookie->data, 0, 4);
 180         return 0;
 181 out_size:
 182         dprintk("NFS: returned cookie was too long: %u\n", length);
 183         return -EIO;
 184 out_overflow:
 185         print_overflow_msg(__func__, xdr);
 186         return -EIO;
 187 }
 188
 189 /*
 190  *      netobj fh;
 191  */
 192 static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh)
 193 {
 194         encode_netobj(xdr, (u8 *)&fh->data, NFS2_FHSIZE);
 195 }
 196
 197 /*
 198  *      enum nlm_stats {
 199  *              LCK_GRANTED = 0,
 200  *              LCK_DENIED = 1,
 201  *              LCK_DENIED_NOLOCKS = 2,
 202  *              LCK_BLOCKED = 3,
 203  *              LCK_DENIED_GRACE_PERIOD = 4
 204  *      };
 205  *
 206  *
 207  *      struct nlm_stat {
 208  *              nlm_stats stat;
 209  *      };
 210  *
 211  * NB: we don't swap bytes for the NLM status values.  The upper
 212  * layers deal directly with the status value in network byte
 213  * order.
 214  */
 215
 216 static void encode_nlm_stat(struct xdr_stream *xdr,
 217                             const __be32 stat)
 218 {
 219         __be32 *p;
 220
 221         WARN_ON_ONCE(be32_to_cpu(stat) > NLM_LCK_DENIED_GRACE_PERIOD);
 222         p = xdr_reserve_space(xdr, 4);
 223         *p = stat;
 224 }
 225
 226 static int decode_nlm_stat(struct xdr_stream *xdr,
 227                            __be32 *stat)
 228 {
 229         __be32 *p;
 230
 231         p = xdr_inline_decode(xdr, 4);
 232         if (unlikely(p == NULL))
 233                 goto out_overflow;
 234         if (unlikely(ntohl(*p) > ntohl(nlm_lck_denied_grace_period)))
 235                 goto out_enum;
 236         *stat = *p;
 237         return 0;
 238 out_enum:
 239         dprintk("%s: server returned invalid nlm_stats value: %u\n",
 240                 __func__, be32_to_cpup(p));
 241         return -EIO;
 242 out_overflow:
 243         print_overflow_msg(__func__, xdr);
 244         return -EIO;
 245 }
 246
 247 /*
 248  *      struct nlm_holder {
 249  *              bool exclusive;
 250  *              int uppid;
 251  *              netobj oh;
 252  *              unsigned l_offset;
 253  *              unsigned l_len;
 254  *      };
 255  */
 256 static void encode_nlm_holder(struct xdr_stream *xdr,
 257                               const struct nlm_res *result)
 258 {
 259         const struct nlm_lock *lock = &result->lock;
 260         u32 l_offset, l_len;
 261         __be32 *p;
 262
 263         encode_bool(xdr, lock->fl.fl_type == F_RDLCK);
 264         encode_int32(xdr, lock->svid);
 265         encode_netobj(xdr, lock->oh.data, lock->oh.len);
 266
 267         p = xdr_reserve_space(xdr, 4 + 4);
 268         nlm_compute_offsets(lock, &l_offset, &l_len);
 269         *p++ = cpu_to_be32(l_offset);
 270         *p   = cpu_to_be32(l_len);
 271 }
 272
 273 static int decode_nlm_holder(struct xdr_stream *xdr, struct nlm_res *result)
 274 {
 275         struct nlm_lock *lock = &result->lock;
 276         struct file_lock *fl = &lock->fl;
 277         u32 exclusive, l_offset, l_len;
 278         int error;
 279         __be32 *p;
 280         s32 end;
 281
 282         memset(lock, 0, sizeof(*lock));
 283         locks_init_lock(fl);
 284
 285         p = xdr_inline_decode(xdr, 4 + 4);
 286         if (unlikely(p == NULL))
 287                 goto out_overflow;
 288         exclusive = be32_to_cpup(p++);
 289         lock->svid = be32_to_cpup(p);
 290         fl->fl_pid = (pid_t)lock->svid;
 291
 292         error = decode_netobj(xdr, &lock->oh);
 293         if (unlikely(error))
 294                 goto out;
 295
 296         p = xdr_inline_decode(xdr, 4 + 4);
 297         if (unlikely(p == NULL))
 298                 goto out_overflow;
 299
 300         fl->fl_flags = FL_POSIX;
 301         fl->fl_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
 302         l_offset = be32_to_cpup(p++);
 303         l_len = be32_to_cpup(p);
 304         end = l_offset + l_len - 1;
 305
 306         fl->fl_start = (loff_t)l_offset;
 307         if (l_len == 0 || end < 0)
 308                 fl->fl_end = OFFSET_MAX;
 309         else
 310                 fl->fl_end = (loff_t)end;
 311         error = 0;
 312 out:
 313         return error;
 314 out_overflow:
 315         print_overflow_msg(__func__, xdr);
 316         return -EIO;
 317 }
 318
 319 /*
 320  *      string caller_name<LM_MAXSTRLEN>;
 321  */
 322 static void encode_caller_name(struct xdr_stream *xdr, const char *name)
 323 {
 324         /* NB: client-side does not set lock->len */
 325         u32 length = strlen(name);
 326         __be32 *p;
 327
 328         p = xdr_reserve_space(xdr, 4 + length);
 329         xdr_encode_opaque(p, name, length);
 330 }
 331
 332 /*
 333  *      struct nlm_lock {
 334  *              string caller_name<LM_MAXSTRLEN>;
 335  *              netobj fh;
 336  *              netobj oh;
 337  *              int uppid;
 338  *              unsigned l_offset;
 339  *              unsigned l_len;
 340  *      };
 341  */
 342 static void encode_nlm_lock(struct xdr_stream *xdr,
 343                             const struct nlm_lock *lock)
 344 {
 345         u32 l_offset, l_len;
 346         __be32 *p;
 347
 348         encode_caller_name(xdr, lock->caller);
 349         encode_fh(xdr, &lock->fh);
 350         encode_netobj(xdr, lock->oh.data, lock->oh.len);
 351
 352         p = xdr_reserve_space(xdr, 4 + 4 + 4);
 353         *p++ = cpu_to_be32(lock->svid);
 354
 355         nlm_compute_offsets(lock, &l_offset, &l_len);
 356         *p++ = cpu_to_be32(l_offset);
 357         *p   = cpu_to_be32(l_len);
 358 }
 359
 360
 361 /*
 362  * NLMv3 XDR encode functions
 363  *
 364  * NLMv3 argument types are defined in Chapter 10 of The Open Group's
 365  * "Protocols for Interworking: XNFS, Version 3W".
 366  */
 367
 368 /*
 369  *      struct nlm_testargs {
 370  *              netobj cookie;
 371  *              bool exclusive;
 372  *              struct nlm_lock alock;
 373  *      };
 374  */
 375 static void nlm_xdr_enc_testargs(struct rpc_rqst *req,
 376                                  struct xdr_stream *xdr,
 377                                  const struct nlm_args *args)
 378 {
 379         const struct nlm_lock *lock = &args->lock;
 380
 381         encode_cookie(xdr, &args->cookie);
 382         encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
 383         encode_nlm_lock(xdr, lock);
 384 }
 385
 386 /*
 387  *      struct nlm_lockargs {
 388  *              netobj cookie;
 389  *              bool block;
 390  *              bool exclusive;
 391  *              struct nlm_lock alock;
 392  *              bool reclaim;
 393  *              int state;
 394  *      };
 395  */
 396 static void nlm_xdr_enc_lockargs(struct rpc_rqst *req,
 397                                  struct xdr_stream *xdr,
 398                                  const struct nlm_args *args)
 399 {
 400         const struct nlm_lock *lock = &args->lock;
 401
 402         encode_cookie(xdr, &args->cookie);
 403         encode_bool(xdr, args->block);
 404         encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
 405         encode_nlm_lock(xdr, lock);
 406         encode_bool(xdr, args->reclaim);
 407         encode_int32(xdr, args->state);
 408 }
 409
 410 /*
 411  *      struct nlm_cancargs {
 412  *              netobj cookie;
 413  *              bool block;
 414  *              bool exclusive;
 415  *              struct nlm_lock alock;
 416  *      };
 417  */
 418 static void nlm_xdr_enc_cancargs(struct rpc_rqst *req,
 419                                  struct xdr_stream *xdr,
 420                                  const struct nlm_args *args)
 421 {
 422         const struct nlm_lock *lock = &args->lock;
 423
 424         encode_cookie(xdr, &args->cookie);
 425         encode_bool(xdr, args->block);
 426         encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
 427         encode_nlm_lock(xdr, lock);
 428 }
 429
 430 /*
 431  *      struct nlm_unlockargs {
 432  *              netobj cookie;
 433  *              struct nlm_lock alock;
 434  *      };
 435  */
 436 static void nlm_xdr_enc_unlockargs(struct rpc_rqst *req,
 437                                    struct xdr_stream *xdr,
 438                                    const struct nlm_args *args)
 439 {
 440         const struct nlm_lock *lock = &args->lock;
 441
 442         encode_cookie(xdr, &args->cookie);
 443         encode_nlm_lock(xdr, lock);
 444 }
 445
 446 /*
 447  *      struct nlm_res {
 448  *              netobj cookie;
 449  *              nlm_stat stat;
 450  *      };
 451  */
 452 static void nlm_xdr_enc_res(struct rpc_rqst *req,
 453                             struct xdr_stream *xdr,
 454                             const struct nlm_res *result)
 455 {
 456         encode_cookie(xdr, &result->cookie);
 457         encode_nlm_stat(xdr, result->status);
 458 }
 459
 460 /*
 461  *      union nlm_testrply switch (nlm_stats stat) {
 462  *      case LCK_DENIED:
 463  *              struct nlm_holder holder;
 464  *      default:
 465  *              void;
 466  *      };
 467  *
 468  *      struct nlm_testres {
 469  *              netobj cookie;
 470  *              nlm_testrply test_stat;
 471  *      };
 472  */
 473 static void encode_nlm_testrply(struct xdr_stream *xdr,
 474                                 const struct nlm_res *result)
 475 {
 476         if (result->status == nlm_lck_denied)
 477                 encode_nlm_holder(xdr, result);
 478 }
 479
 480 static void nlm_xdr_enc_testres(struct rpc_rqst *req,
 481                                 struct xdr_stream *xdr,
 482                                 const struct nlm_res *result)
 483 {
 484         encode_cookie(xdr, &result->cookie);
 485         encode_nlm_stat(xdr, result->status);
 486         encode_nlm_testrply(xdr, result);
 487 }
 488
 489
 490 /*
 491  * NLMv3 XDR decode functions
 492  *
 493  * NLMv3 result types are defined in Chapter 10 of The Open Group's
 494  * "Protocols for Interworking: XNFS, Version 3W".
 495  */
 496
 497 /*
 498  *      union nlm_testrply switch (nlm_stats stat) {
 499  *      case LCK_DENIED:
 500  *              struct nlm_holder holder;
 501  *      default:
 502  *              void;
 503  *      };
 504  *
 505  *      struct nlm_testres {
 506  *              netobj cookie;
 507  *              nlm_testrply test_stat;
 508  *      };
 509  */
 510 static int decode_nlm_testrply(struct xdr_stream *xdr,
 511                                struct nlm_res *result)
 512 {
 513         int error;
 514
 515         error = decode_nlm_stat(xdr, &result->status);
 516         if (unlikely(error))
 517                 goto out;
 518         if (result->status == nlm_lck_denied)
 519                 error = decode_nlm_holder(xdr, result);
 520 out:
 521         return error;
 522 }
 523
 524 static int nlm_xdr_dec_testres(struct rpc_rqst *req,
 525                                struct xdr_stream *xdr,
 526                                struct nlm_res *result)
 527 {
 528         int error;
 529
 530         error = decode_cookie(xdr, &result->cookie);
 531         if (unlikely(error))
 532                 goto out;
 533         error = decode_nlm_testrply(xdr, result);
 534 out:
 535         return error;
 536 }
 537
 538 /*
 539  *      struct nlm_res {
 540  *              netobj cookie;
 541  *              nlm_stat stat;
 542  *      };
 543  */
 544 static int nlm_xdr_dec_res(struct rpc_rqst *req,
 545                            struct xdr_stream *xdr,
 546                            struct nlm_res *result)
 547 {
 548         int error;
 549
 550         error = decode_cookie(xdr, &result->cookie);
 551         if (unlikely(error))
 552                 goto out;
 553         error = decode_nlm_stat(xdr, &result->status);
 554 out:
 555         return error;
 556 }
 557
 558
 559 /*
 560  * For NLM, a void procedure really returns nothing
 561  */
 562 #define nlm_xdr_dec_norep       NULL
 563
 564 #define PROC(proc, argtype, restype)    \
 565 [NLMPROC_##proc] = {                                                    \
 566         .p_proc      = NLMPROC_##proc,                                  \
 567         .p_encode    = (kxdreproc_t)nlm_xdr_enc_##argtype,              \
 568         .p_decode    = (kxdrdproc_t)nlm_xdr_dec_##restype,              \
 569         .p_arglen    = NLM_##argtype##_sz,                              \
 570         .p_replen    = NLM_##restype##_sz,                              \
 571         .p_statidx   = NLMPROC_##proc,                                  \
 572         .p_name      = #proc,                                           \
 573         }
 574
 575 static struct rpc_procinfo      nlm_procedures[] = {
 576         PROC(TEST,              testargs,       testres),
 577         PROC(LOCK,              lockargs,       res),
 578         PROC(CANCEL,            cancargs,       res),
 579         PROC(UNLOCK,            unlockargs,     res),
 580         PROC(GRANTED,           testargs,       res),
 581         PROC(TEST_MSG,          testargs,       norep),
 582         PROC(LOCK_MSG,          lockargs,       norep),
 583         PROC(CANCEL_MSG,        cancargs,       norep),
 584         PROC(UNLOCK_MSG,        unlockargs,     norep),
 585         PROC(GRANTED_MSG,       testargs,       norep),
 586         PROC(TEST_RES,          testres,        norep),
 587         PROC(LOCK_RES,          res,            norep),
 588         PROC(CANCEL_RES,        res,            norep),
 589         PROC(UNLOCK_RES,        res,            norep),
 590         PROC(GRANTED_RES,       res,            norep),
 591 };
 592
 593 static const struct rpc_version nlm_version1 = {
 594                 .number         = 1,
 595                 .nrprocs        = ARRAY_SIZE(nlm_procedures),
 596                 .procs          = nlm_procedures,
 597 };
 598
 599 static const struct rpc_version nlm_version3 = {
 600                 .number         = 3,
 601                 .nrprocs        = ARRAY_SIZE(nlm_procedures),
 602                 .procs          = nlm_procedures,
 603 };
 604
 605 static const struct rpc_version *nlm_versions[] = {
 606         [1] = &nlm_version1,
 607         [3] = &nlm_version3,
 608 #ifdef CONFIG_LOCKD_V4
 609         [4] = &nlm_version4,
 610 #endif
 611 };
 612
 613 static struct rpc_stat          nlm_rpc_stats;
 614
 615 const struct rpc_program        nlm_program = {
 616                 .name           = "lockd",
 617                 .number         = NLM_PROGRAM,
 618                 .nrvers         = ARRAY_SIZE(nlm_versions),
 619                 .version        = nlm_versions,
 620                 .stats          = &nlm_rpc_stats,
 621 };