fs/lockd/clntxdr.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * linux/fs/lockd/clntxdr.c
   4  *
   5  * XDR functions to encode/decode NLM version 3 RPC arguments and results.
   6  * NLM version 3 is backwards compatible with NLM versions 1 and 2.
   7  *
   8  * NLM client-side only.
   9  *
  10  * Copyright (C) 2010, Oracle.  All rights reserved.
  11  */
  12
  13 #include <linux/types.h>
  14 #include <linux/sunrpc/xdr.h>
  15 #include <linux/sunrpc/clnt.h>
  16 #include <linux/sunrpc/stats.h>
  17 #include <linux/lockd/lockd.h>
  18
  19 #include <uapi/linux/nfs2.h>
  20
  21 #define NLMDBG_FACILITY         NLMDBG_XDR
  22
  23 #if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)
  24 #  error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"
  25 #endif
  26
  27 /*
  28  * Declare the space requirements for NLM arguments and replies as
  29  * number of 32bit-words
  30  */
  31 #define NLM_cookie_sz           (1+(NLM_MAXCOOKIELEN>>2))
  32 #define NLM_caller_sz           (1+(NLMCLNT_OHSIZE>>2))
  33 #define NLM_owner_sz            (1+(NLMCLNT_OHSIZE>>2))
  34 #define NLM_fhandle_sz          (1+(NFS2_FHSIZE>>2))
  35 #define NLM_lock_sz             (3+NLM_caller_sz+NLM_owner_sz+NLM_fhandle_sz)
  36 #define NLM_holder_sz           (4+NLM_owner_sz)
  37
  38 #define NLM_testargs_sz         (NLM_cookie_sz+1+NLM_lock_sz)
  39 #define NLM_lockargs_sz         (NLM_cookie_sz+4+NLM_lock_sz)
  40 #define NLM_cancargs_sz         (NLM_cookie_sz+2+NLM_lock_sz)
  41 #define NLM_unlockargs_sz       (NLM_cookie_sz+NLM_lock_sz)
  42
  43 #define NLM_testres_sz          (NLM_cookie_sz+1+NLM_holder_sz)
  44 #define NLM_res_sz              (NLM_cookie_sz+1)
  45 #define NLM_norep_sz            (0)
  46
  47
  48 static s32 loff_t_to_s32(loff_t offset)
  49 {
  50         s32 res;
  51
  52         if (offset >= NLM_OFFSET_MAX)
  53                 res = NLM_OFFSET_MAX;
  54         else if (offset <= -NLM_OFFSET_MAX)
  55                 res = -NLM_OFFSET_MAX;
  56         else
  57                 res = offset;
  58         return res;
  59 }
  60
  61 static void nlm_compute_offsets(const struct nlm_lock *lock,
  62                                 u32 *l_offset, u32 *l_len)
  63 {
  64         const struct file_lock *fl = &lock->fl;
  65
  66         *l_offset = loff_t_to_s32(fl->fl_start);
  67         if (fl->fl_end == OFFSET_MAX)
  68                 *l_len = 0;
  69         else
  70                 *l_len = loff_t_to_s32(fl->fl_end - fl->fl_start + 1);
  71 }
  72
  73 /*
  74  * Handle decode buffer overflows out-of-line.
  75  */
  76 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
  77 {
  78         dprintk("lockd: %s prematurely hit the end of our receive buffer. "
  79                 "Remaining buffer length is %tu words.\n",
  80                 func, xdr->end - xdr->p);
  81 }
  82
  83
  84 /*
  85  * Encode/decode NLMv3 basic data types
  86  *
  87  * Basic NLMv3 data types are not defined in an IETF standards
  88  * document.  X/Open has a description of these data types that
  89  * is useful.  See Chapter 10 of "Protocols for Interworking:
  90  * XNFS, Version 3W".
  91  *
  92  * Not all basic data types have their own encoding and decoding
  93  * functions.  For run-time efficiency, some data types are encoded
  94  * or decoded inline.
  95  */
  96
  97 static void encode_bool(struct xdr_stream *xdr, const int value)
  98 {
  99         __be32 *p;
 100
 101         p = xdr_reserve_space(xdr, 4);
 102         *p = value ? xdr_one : xdr_zero;
 103 }
 104
 105 static void encode_int32(struct xdr_stream *xdr, const s32 value)
 106 {
 107         __be32 *p;
 108
 109         p = xdr_reserve_space(xdr, 4);
 110         *p = cpu_to_be32(value);
 111 }
 112
 113 /*
 114  *      typedef opaque netobj<MAXNETOBJ_SZ>
 115  */
 116 static void encode_netobj(struct xdr_stream *xdr,
 117                           const u8 *data, const unsigned int length)
 118 {
 119         __be32 *p;
 120
 121         p = xdr_reserve_space(xdr, 4 + length);
 122         xdr_encode_opaque(p, data, length);
 123 }
 124
 125 static int decode_netobj(struct xdr_stream *xdr,
 126                          struct xdr_netobj *obj)
 127 {
 128         ssize_t ret;
 129
 130         ret = xdr_stream_decode_opaque_inline(xdr, (void *)&obj->data,
 131                         XDR_MAX_NETOBJ);
 132         if (unlikely(ret < 0))
 133                 return -EIO;
 134         obj->len = ret;
 135         return 0;
 136 }
 137
 138 /*
 139  *      netobj cookie;
 140  */
 141 static void encode_cookie(struct xdr_stream *xdr,
 142                           const struct nlm_cookie *cookie)
 143 {
 144         encode_netobj(xdr, (u8 *)&cookie->data, cookie->len);
 145 }
 146
 147 static int decode_cookie(struct xdr_stream *xdr,
 148                          struct nlm_cookie *cookie)
 149 {
 150         u32 length;
 151         __be32 *p;
 152
 153         p = xdr_inline_decode(xdr, 4);
 154         if (unlikely(p == NULL))
 155                 goto out_overflow;
 156         length = be32_to_cpup(p++);
 157         /* apparently HPUX can return empty cookies */
 158         if (length == 0)
 159                 goto out_hpux;
 160         if (length > NLM_MAXCOOKIELEN)
 161                 goto out_size;
 162         p = xdr_inline_decode(xdr, length);
 163         if (unlikely(p == NULL))
 164                 goto out_overflow;
 165         cookie->len = length;
 166         memcpy(cookie->data, p, length);
 167         return 0;
 168 out_hpux:
 169         cookie->len = 4;
 170         memset(cookie->data, 0, 4);
 171         return 0;
 172 out_size:
 173         dprintk("NFS: returned cookie was too long: %u\n", length);
 174         return -EIO;
 175 out_overflow:
 176         print_overflow_msg(__func__, xdr);
 177         return -EIO;
 178 }
 179
 180 /*
 181  *      netobj fh;
 182  */
 183 static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh)
 184 {
 185         encode_netobj(xdr, (u8 *)&fh->data, NFS2_FHSIZE);
 186 }
 187
 188 /*
 189  *      enum nlm_stats {
 190  *              LCK_GRANTED = 0,
 191  *              LCK_DENIED = 1,
 192  *              LCK_DENIED_NOLOCKS = 2,
 193  *              LCK_BLOCKED = 3,
 194  *              LCK_DENIED_GRACE_PERIOD = 4
 195  *      };
 196  *
 197  *
 198  *      struct nlm_stat {
 199  *              nlm_stats stat;
 200  *      };
 201  *
 202  * NB: we don't swap bytes for the NLM status values.  The upper
 203  * layers deal directly with the status value in network byte
 204  * order.
 205  */
 206
 207 static void encode_nlm_stat(struct xdr_stream *xdr,
 208                             const __be32 stat)
 209 {
 210         __be32 *p;
 211
 212         WARN_ON_ONCE(be32_to_cpu(stat) > NLM_LCK_DENIED_GRACE_PERIOD);
 213         p = xdr_reserve_space(xdr, 4);
 214         *p = stat;
 215 }
 216
 217 static int decode_nlm_stat(struct xdr_stream *xdr,
 218                            __be32 *stat)
 219 {
 220         __be32 *p;
 221
 222         p = xdr_inline_decode(xdr, 4);
 223         if (unlikely(p == NULL))
 224                 goto out_overflow;
 225         if (unlikely(ntohl(*p) > ntohl(nlm_lck_denied_grace_period)))
 226                 goto out_enum;
 227         *stat = *p;
 228         return 0;
 229 out_enum:
 230         dprintk("%s: server returned invalid nlm_stats value: %u\n",
 231                 __func__, be32_to_cpup(p));
 232         return -EIO;
 233 out_overflow:
 234         print_overflow_msg(__func__, xdr);
 235         return -EIO;
 236 }
 237
 238 /*
 239  *      struct nlm_holder {
 240  *              bool exclusive;
 241  *              int uppid;
 242  *              netobj oh;
 243  *              unsigned l_offset;
 244  *              unsigned l_len;
 245  *      };
 246  */
 247 static void encode_nlm_holder(struct xdr_stream *xdr,
 248                               const struct nlm_res *result)
 249 {
 250         const struct nlm_lock *lock = &result->lock;
 251         u32 l_offset, l_len;
 252         __be32 *p;
 253
 254         encode_bool(xdr, lock->fl.fl_type == F_RDLCK);
 255         encode_int32(xdr, lock->svid);
 256         encode_netobj(xdr, lock->oh.data, lock->oh.len);
 257
 258         p = xdr_reserve_space(xdr, 4 + 4);
 259         nlm_compute_offsets(lock, &l_offset, &l_len);
 260         *p++ = cpu_to_be32(l_offset);
 261         *p   = cpu_to_be32(l_len);
 262 }
 263
 264 static int decode_nlm_holder(struct xdr_stream *xdr, struct nlm_res *result)
 265 {
 266         struct nlm_lock *lock = &result->lock;
 267         struct file_lock *fl = &lock->fl;
 268         u32 exclusive, l_offset, l_len;
 269         int error;
 270         __be32 *p;
 271         s32 end;
 272
 273         memset(lock, 0, sizeof(*lock));
 274         locks_init_lock(fl);
 275
 276         p = xdr_inline_decode(xdr, 4 + 4);
 277         if (unlikely(p == NULL))
 278                 goto out_overflow;
 279         exclusive = be32_to_cpup(p++);
 280         lock->svid = be32_to_cpup(p);
 281         fl->fl_pid = (pid_t)lock->svid;
 282
 283         error = decode_netobj(xdr, &lock->oh);
 284         if (unlikely(error))
 285                 goto out;
 286
 287         p = xdr_inline_decode(xdr, 4 + 4);
 288         if (unlikely(p == NULL))
 289                 goto out_overflow;
 290
 291         fl->fl_flags = FL_POSIX;
 292         fl->fl_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
 293         l_offset = be32_to_cpup(p++);
 294         l_len = be32_to_cpup(p);
 295         end = l_offset + l_len - 1;
 296
 297         fl->fl_start = (loff_t)l_offset;
 298         if (l_len == 0 || end < 0)
 299                 fl->fl_end = OFFSET_MAX;
 300         else
 301                 fl->fl_end = (loff_t)end;
 302         error = 0;
 303 out:
 304         return error;
 305 out_overflow:
 306         print_overflow_msg(__func__, xdr);
 307         return -EIO;
 308 }
 309
 310 /*
 311  *      string caller_name<LM_MAXSTRLEN>;
 312  */
 313 static void encode_caller_name(struct xdr_stream *xdr, const char *name)
 314 {
 315         /* NB: client-side does not set lock->len */
 316         u32 length = strlen(name);
 317         __be32 *p;
 318
 319         p = xdr_reserve_space(xdr, 4 + length);
 320         xdr_encode_opaque(p, name, length);
 321 }
 322
 323 /*
 324  *      struct nlm_lock {
 325  *              string caller_name<LM_MAXSTRLEN>;
 326  *              netobj fh;
 327  *              netobj oh;
 328  *              int uppid;
 329  *              unsigned l_offset;
 330  *              unsigned l_len;
 331  *      };
 332  */
 333 static void encode_nlm_lock(struct xdr_stream *xdr,
 334                             const struct nlm_lock *lock)
 335 {
 336         u32 l_offset, l_len;
 337         __be32 *p;
 338
 339         encode_caller_name(xdr, lock->caller);
 340         encode_fh(xdr, &lock->fh);
 341         encode_netobj(xdr, lock->oh.data, lock->oh.len);
 342
 343         p = xdr_reserve_space(xdr, 4 + 4 + 4);
 344         *p++ = cpu_to_be32(lock->svid);
 345
 346         nlm_compute_offsets(lock, &l_offset, &l_len);
 347         *p++ = cpu_to_be32(l_offset);
 348         *p   = cpu_to_be32(l_len);
 349 }
 350
 351
 352 /*
 353  * NLMv3 XDR encode functions
 354  *
 355  * NLMv3 argument types are defined in Chapter 10 of The Open Group's
 356  * "Protocols for Interworking: XNFS, Version 3W".
 357  */
 358
 359 /*
 360  *      struct nlm_testargs {
 361  *              netobj cookie;
 362  *              bool exclusive;
 363  *              struct nlm_lock alock;
 364  *      };
 365  */
 366 static void nlm_xdr_enc_testargs(struct rpc_rqst *req,
 367                                  struct xdr_stream *xdr,
 368                                  const void *data)
 369 {
 370         const struct nlm_args *args = data;
 371         const struct nlm_lock *lock = &args->lock;
 372
 373         encode_cookie(xdr, &args->cookie);
 374         encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
 375         encode_nlm_lock(xdr, lock);
 376 }
 377
 378 /*
 379  *      struct nlm_lockargs {
 380  *              netobj cookie;
 381  *              bool block;
 382  *              bool exclusive;
 383  *              struct nlm_lock alock;
 384  *              bool reclaim;
 385  *              int state;
 386  *      };
 387  */
 388 static void nlm_xdr_enc_lockargs(struct rpc_rqst *req,
 389                                  struct xdr_stream *xdr,
 390                                  const void *data)
 391 {
 392         const struct nlm_args *args = data;
 393         const struct nlm_lock *lock = &args->lock;
 394
 395         encode_cookie(xdr, &args->cookie);
 396         encode_bool(xdr, args->block);
 397         encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
 398         encode_nlm_lock(xdr, lock);
 399         encode_bool(xdr, args->reclaim);
 400         encode_int32(xdr, args->state);
 401 }
 402
 403 /*
 404  *      struct nlm_cancargs {
 405  *              netobj cookie;
 406  *              bool block;
 407  *              bool exclusive;
 408  *              struct nlm_lock alock;
 409  *      };
 410  */
 411 static void nlm_xdr_enc_cancargs(struct rpc_rqst *req,
 412                                  struct xdr_stream *xdr,
 413                                  const void *data)
 414 {
 415         const struct nlm_args *args = data;
 416         const struct nlm_lock *lock = &args->lock;
 417
 418         encode_cookie(xdr, &args->cookie);
 419         encode_bool(xdr, args->block);
 420         encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
 421         encode_nlm_lock(xdr, lock);
 422 }
 423
 424 /*
 425  *      struct nlm_unlockargs {
 426  *              netobj cookie;
 427  *              struct nlm_lock alock;
 428  *      };
 429  */
 430 static void nlm_xdr_enc_unlockargs(struct rpc_rqst *req,
 431                                    struct xdr_stream *xdr,
 432                                    const void *data)
 433 {
 434         const struct nlm_args *args = data;
 435         const struct nlm_lock *lock = &args->lock;
 436
 437         encode_cookie(xdr, &args->cookie);
 438         encode_nlm_lock(xdr, lock);
 439 }
 440
 441 /*
 442  *      struct nlm_res {
 443  *              netobj cookie;
 444  *              nlm_stat stat;
 445  *      };
 446  */
 447 static void nlm_xdr_enc_res(struct rpc_rqst *req,
 448                             struct xdr_stream *xdr,
 449                             const void *data)
 450 {
 451         const struct nlm_res *result = data;
 452
 453         encode_cookie(xdr, &result->cookie);
 454         encode_nlm_stat(xdr, result->status);
 455 }
 456
 457 /*
 458  *      union nlm_testrply switch (nlm_stats stat) {
 459  *      case LCK_DENIED:
 460  *              struct nlm_holder holder;
 461  *      default:
 462  *              void;
 463  *      };
 464  *
 465  *      struct nlm_testres {
 466  *              netobj cookie;
 467  *              nlm_testrply test_stat;
 468  *      };
 469  */
 470 static void encode_nlm_testrply(struct xdr_stream *xdr,
 471                                 const struct nlm_res *result)
 472 {
 473         if (result->status == nlm_lck_denied)
 474                 encode_nlm_holder(xdr, result);
 475 }
 476
 477 static void nlm_xdr_enc_testres(struct rpc_rqst *req,
 478                                 struct xdr_stream *xdr,
 479                                 const void *data)
 480 {
 481         const struct nlm_res *result = data;
 482
 483         encode_cookie(xdr, &result->cookie);
 484         encode_nlm_stat(xdr, result->status);
 485         encode_nlm_testrply(xdr, result);
 486 }
 487
 488
 489 /*
 490  * NLMv3 XDR decode functions
 491  *
 492  * NLMv3 result types are defined in Chapter 10 of The Open Group's
 493  * "Protocols for Interworking: XNFS, Version 3W".
 494  */
 495
 496 /*
 497  *      union nlm_testrply switch (nlm_stats stat) {
 498  *      case LCK_DENIED:
 499  *              struct nlm_holder holder;
 500  *      default:
 501  *              void;
 502  *      };
 503  *
 504  *      struct nlm_testres {
 505  *              netobj cookie;
 506  *              nlm_testrply test_stat;
 507  *      };
 508  */
 509 static int decode_nlm_testrply(struct xdr_stream *xdr,
 510                                struct nlm_res *result)
 511 {
 512         int error;
 513
 514         error = decode_nlm_stat(xdr, &result->status);
 515         if (unlikely(error))
 516                 goto out;
 517         if (result->status == nlm_lck_denied)
 518                 error = decode_nlm_holder(xdr, result);
 519 out:
 520         return error;
 521 }
 522
 523 static int nlm_xdr_dec_testres(struct rpc_rqst *req,
 524                                struct xdr_stream *xdr,
 525                                void *data)
 526 {
 527         struct nlm_res *result = data;
 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                            void *data)
 547 {
 548         struct nlm_res *result = data;
 549         int error;
 550
 551         error = decode_cookie(xdr, &result->cookie);
 552         if (unlikely(error))
 553                 goto out;
 554         error = decode_nlm_stat(xdr, &result->status);
 555 out:
 556         return error;
 557 }
 558
 559
 560 /*
 561  * For NLM, a void procedure really returns nothing
 562  */
 563 #define nlm_xdr_dec_norep       NULL
 564
 565 #define PROC(proc, argtype, restype)    \
 566 [NLMPROC_##proc] = {                                                    \
 567         .p_proc      = NLMPROC_##proc,                                  \
 568         .p_encode    = nlm_xdr_enc_##argtype,           \
 569         .p_decode    = nlm_xdr_dec_##restype,                           \
 570         .p_arglen    = NLM_##argtype##_sz,                              \
 571         .p_replen    = NLM_##restype##_sz,                              \
 572         .p_statidx   = NLMPROC_##proc,                                  \
 573         .p_name      = #proc,                                           \
 574         }
 575
 576 static const struct rpc_procinfo nlm_procedures[] = {
 577         PROC(TEST,              testargs,       testres),
 578         PROC(LOCK,              lockargs,       res),
 579         PROC(CANCEL,            cancargs,       res),
 580         PROC(UNLOCK,            unlockargs,     res),
 581         PROC(GRANTED,           testargs,       res),
 582         PROC(TEST_MSG,          testargs,       norep),
 583         PROC(LOCK_MSG,          lockargs,       norep),
 584         PROC(CANCEL_MSG,        cancargs,       norep),
 585         PROC(UNLOCK_MSG,        unlockargs,     norep),
 586         PROC(GRANTED_MSG,       testargs,       norep),
 587         PROC(TEST_RES,          testres,        norep),
 588         PROC(LOCK_RES,          res,            norep),
 589         PROC(CANCEL_RES,        res,            norep),
 590         PROC(UNLOCK_RES,        res,            norep),
 591         PROC(GRANTED_RES,       res,            norep),
 592 };
 593
 594 static unsigned int nlm_version1_counts[ARRAY_SIZE(nlm_procedures)];
 595 static const struct rpc_version nlm_version1 = {
 596         .number         = 1,
 597         .nrprocs        = ARRAY_SIZE(nlm_procedures),
 598         .procs          = nlm_procedures,
 599         .counts         = nlm_version1_counts,
 600 };
 601
 602 static unsigned int nlm_version3_counts[ARRAY_SIZE(nlm_procedures)];
 603 static const struct rpc_version nlm_version3 = {
 604         .number         = 3,
 605         .nrprocs        = ARRAY_SIZE(nlm_procedures),
 606         .procs          = nlm_procedures,
 607         .counts         = nlm_version3_counts,
 608 };
 609
 610 static const struct rpc_version *nlm_versions[] = {
 611         [1] = &nlm_version1,
 612         [3] = &nlm_version3,
 613 #ifdef CONFIG_LOCKD_V4
 614         [4] = &nlm_version4,
 615 #endif
 616 };
 617
 618 static struct rpc_stat          nlm_rpc_stats;
 619
 620 const struct rpc_program        nlm_program = {
 621         .name           = "lockd",
 622         .number         = NLM_PROGRAM,
 623         .nrvers         = ARRAY_SIZE(nlm_versions),
 624         .version        = nlm_versions,
 625         .stats          = &nlm_rpc_stats,
 626 };