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         u32 length;
 129         __be32 *p;
 130
 131         p = xdr_inline_decode(xdr, 4);
 132         if (unlikely(p == NULL))
 133                 goto out_overflow;
 134         length = be32_to_cpup(p++);
 135         if (unlikely(length > XDR_MAX_NETOBJ))
 136                 goto out_size;
 137         obj->len = length;
 138         obj->data = (u8 *)p;
 139         return 0;
 140 out_size:
 141         dprintk("NFS: returned netobj was too long: %u\n", length);
 142         return -EIO;
 143 out_overflow:
 144         print_overflow_msg(__func__, xdr);
 145         return -EIO;
 146 }
 147
 148 /*
 149  *      netobj cookie;
 150  */
 151 static void encode_cookie(struct xdr_stream *xdr,
 152                           const struct nlm_cookie *cookie)
 153 {
 154         encode_netobj(xdr, (u8 *)&cookie->data, cookie->len);
 155 }
 156
 157 static int decode_cookie(struct xdr_stream *xdr,
 158                          struct nlm_cookie *cookie)
 159 {
 160         u32 length;
 161         __be32 *p;
 162
 163         p = xdr_inline_decode(xdr, 4);
 164         if (unlikely(p == NULL))
 165                 goto out_overflow;
 166         length = be32_to_cpup(p++);
 167         /* apparently HPUX can return empty cookies */
 168         if (length == 0)
 169                 goto out_hpux;
 170         if (length > NLM_MAXCOOKIELEN)
 171                 goto out_size;
 172         p = xdr_inline_decode(xdr, length);
 173         if (unlikely(p == NULL))
 174                 goto out_overflow;
 175         cookie->len = length;
 176         memcpy(cookie->data, p, length);
 177         return 0;
 178 out_hpux:
 179         cookie->len = 4;
 180         memset(cookie->data, 0, 4);
 181         return 0;
 182 out_size:
 183         dprintk("NFS: returned cookie was too long: %u\n", length);
 184         return -EIO;
 185 out_overflow:
 186         print_overflow_msg(__func__, xdr);
 187         return -EIO;
 188 }
 189
 190 /*
 191  *      netobj fh;
 192  */
 193 static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh)
 194 {
 195         encode_netobj(xdr, (u8 *)&fh->data, NFS2_FHSIZE);
 196 }
 197
 198 /*
 199  *      enum nlm_stats {
 200  *              LCK_GRANTED = 0,
 201  *              LCK_DENIED = 1,
 202  *              LCK_DENIED_NOLOCKS = 2,
 203  *              LCK_BLOCKED = 3,
 204  *              LCK_DENIED_GRACE_PERIOD = 4
 205  *      };
 206  *
 207  *
 208  *      struct nlm_stat {
 209  *              nlm_stats stat;
 210  *      };
 211  *
 212  * NB: we don't swap bytes for the NLM status values.  The upper
 213  * layers deal directly with the status value in network byte
 214  * order.
 215  */
 216
 217 static void encode_nlm_stat(struct xdr_stream *xdr,
 218                             const __be32 stat)
 219 {
 220         __be32 *p;
 221
 222         WARN_ON_ONCE(be32_to_cpu(stat) > NLM_LCK_DENIED_GRACE_PERIOD);
 223         p = xdr_reserve_space(xdr, 4);
 224         *p = stat;
 225 }
 226
 227 static int decode_nlm_stat(struct xdr_stream *xdr,
 228                            __be32 *stat)
 229 {
 230         __be32 *p;
 231
 232         p = xdr_inline_decode(xdr, 4);
 233         if (unlikely(p == NULL))
 234                 goto out_overflow;
 235         if (unlikely(ntohl(*p) > ntohl(nlm_lck_denied_grace_period)))
 236                 goto out_enum;
 237         *stat = *p;
 238         return 0;
 239 out_enum:
 240         dprintk("%s: server returned invalid nlm_stats value: %u\n",
 241                 __func__, be32_to_cpup(p));
 242         return -EIO;
 243 out_overflow:
 244         print_overflow_msg(__func__, xdr);
 245         return -EIO;
 246 }
 247
 248 /*
 249  *      struct nlm_holder {
 250  *              bool exclusive;
 251  *              int uppid;
 252  *              netobj oh;
 253  *              unsigned l_offset;
 254  *              unsigned l_len;
 255  *      };
 256  */
 257 static void encode_nlm_holder(struct xdr_stream *xdr,
 258                               const struct nlm_res *result)
 259 {
 260         const struct nlm_lock *lock = &result->lock;
 261         u32 l_offset, l_len;
 262         __be32 *p;
 263
 264         encode_bool(xdr, lock->fl.fl_type == F_RDLCK);
 265         encode_int32(xdr, lock->svid);
 266         encode_netobj(xdr, lock->oh.data, lock->oh.len);
 267
 268         p = xdr_reserve_space(xdr, 4 + 4);
 269         nlm_compute_offsets(lock, &l_offset, &l_len);
 270         *p++ = cpu_to_be32(l_offset);
 271         *p   = cpu_to_be32(l_len);
 272 }
 273
 274 static int decode_nlm_holder(struct xdr_stream *xdr, struct nlm_res *result)
 275 {
 276         struct nlm_lock *lock = &result->lock;
 277         struct file_lock *fl = &lock->fl;
 278         u32 exclusive, l_offset, l_len;
 279         int error;
 280         __be32 *p;
 281         s32 end;
 282
 283         memset(lock, 0, sizeof(*lock));
 284         locks_init_lock(fl);
 285
 286         p = xdr_inline_decode(xdr, 4 + 4);
 287         if (unlikely(p == NULL))
 288                 goto out_overflow;
 289         exclusive = be32_to_cpup(p++);
 290         lock->svid = be32_to_cpup(p);
 291         fl->fl_pid = (pid_t)lock->svid;
 292
 293         error = decode_netobj(xdr, &lock->oh);
 294         if (unlikely(error))
 295                 goto out;
 296
 297         p = xdr_inline_decode(xdr, 4 + 4);
 298         if (unlikely(p == NULL))
 299                 goto out_overflow;
 300
 301         fl->fl_flags = FL_POSIX;
 302         fl->fl_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
 303         l_offset = be32_to_cpup(p++);
 304         l_len = be32_to_cpup(p);
 305         end = l_offset + l_len - 1;
 306
 307         fl->fl_start = (loff_t)l_offset;
 308         if (l_len == 0 || end < 0)
 309                 fl->fl_end = OFFSET_MAX;
 310         else
 311                 fl->fl_end = (loff_t)end;
 312         error = 0;
 313 out:
 314         return error;
 315 out_overflow:
 316         print_overflow_msg(__func__, xdr);
 317         return -EIO;
 318 }
 319
 320 /*
 321  *      string caller_name<LM_MAXSTRLEN>;
 322  */
 323 static void encode_caller_name(struct xdr_stream *xdr, const char *name)
 324 {
 325         /* NB: client-side does not set lock->len */
 326         u32 length = strlen(name);
 327         __be32 *p;
 328
 329         p = xdr_reserve_space(xdr, 4 + length);
 330         xdr_encode_opaque(p, name, length);
 331 }
 332
 333 /*
 334  *      struct nlm_lock {
 335  *              string caller_name<LM_MAXSTRLEN>;
 336  *              netobj fh;
 337  *              netobj oh;
 338  *              int uppid;
 339  *              unsigned l_offset;
 340  *              unsigned l_len;
 341  *      };
 342  */
 343 static void encode_nlm_lock(struct xdr_stream *xdr,
 344                             const struct nlm_lock *lock)
 345 {
 346         u32 l_offset, l_len;
 347         __be32 *p;
 348
 349         encode_caller_name(xdr, lock->caller);
 350         encode_fh(xdr, &lock->fh);
 351         encode_netobj(xdr, lock->oh.data, lock->oh.len);
 352
 353         p = xdr_reserve_space(xdr, 4 + 4 + 4);
 354         *p++ = cpu_to_be32(lock->svid);
 355
 356         nlm_compute_offsets(lock, &l_offset, &l_len);
 357         *p++ = cpu_to_be32(l_offset);
 358         *p   = cpu_to_be32(l_len);
 359 }
 360
 361
 362 /*
 363  * NLMv3 XDR encode functions
 364  *
 365  * NLMv3 argument types are defined in Chapter 10 of The Open Group's
 366  * "Protocols for Interworking: XNFS, Version 3W".
 367  */
 368
 369 /*
 370  *      struct nlm_testargs {
 371  *              netobj cookie;
 372  *              bool exclusive;
 373  *              struct nlm_lock alock;
 374  *      };
 375  */
 376 static void nlm_xdr_enc_testargs(struct rpc_rqst *req,
 377                                  struct xdr_stream *xdr,
 378                                  const void *data)
 379 {
 380         const struct nlm_args *args = data;
 381         const struct nlm_lock *lock = &args->lock;
 382
 383         encode_cookie(xdr, &args->cookie);
 384         encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
 385         encode_nlm_lock(xdr, lock);
 386 }
 387
 388 /*
 389  *      struct nlm_lockargs {
 390  *              netobj cookie;
 391  *              bool block;
 392  *              bool exclusive;
 393  *              struct nlm_lock alock;
 394  *              bool reclaim;
 395  *              int state;
 396  *      };
 397  */
 398 static void nlm_xdr_enc_lockargs(struct rpc_rqst *req,
 399                                  struct xdr_stream *xdr,
 400                                  const void *data)
 401 {
 402         const struct nlm_args *args = data;
 403         const struct nlm_lock *lock = &args->lock;
 404
 405         encode_cookie(xdr, &args->cookie);
 406         encode_bool(xdr, args->block);
 407         encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
 408         encode_nlm_lock(xdr, lock);
 409         encode_bool(xdr, args->reclaim);
 410         encode_int32(xdr, args->state);
 411 }
 412
 413 /*
 414  *      struct nlm_cancargs {
 415  *              netobj cookie;
 416  *              bool block;
 417  *              bool exclusive;
 418  *              struct nlm_lock alock;
 419  *      };
 420  */
 421 static void nlm_xdr_enc_cancargs(struct rpc_rqst *req,
 422                                  struct xdr_stream *xdr,
 423                                  const void *data)
 424 {
 425         const struct nlm_args *args = data;
 426         const struct nlm_lock *lock = &args->lock;
 427
 428         encode_cookie(xdr, &args->cookie);
 429         encode_bool(xdr, args->block);
 430         encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
 431         encode_nlm_lock(xdr, lock);
 432 }
 433
 434 /*
 435  *      struct nlm_unlockargs {
 436  *              netobj cookie;
 437  *              struct nlm_lock alock;
 438  *      };
 439  */
 440 static void nlm_xdr_enc_unlockargs(struct rpc_rqst *req,
 441                                    struct xdr_stream *xdr,
 442                                    const void *data)
 443 {
 444         const struct nlm_args *args = data;
 445         const struct nlm_lock *lock = &args->lock;
 446
 447         encode_cookie(xdr, &args->cookie);
 448         encode_nlm_lock(xdr, lock);
 449 }
 450
 451 /*
 452  *      struct nlm_res {
 453  *              netobj cookie;
 454  *              nlm_stat stat;
 455  *      };
 456  */
 457 static void nlm_xdr_enc_res(struct rpc_rqst *req,
 458                             struct xdr_stream *xdr,
 459                             const void *data)
 460 {
 461         const struct nlm_res *result = data;
 462
 463         encode_cookie(xdr, &result->cookie);
 464         encode_nlm_stat(xdr, result->status);
 465 }
 466
 467 /*
 468  *      union nlm_testrply switch (nlm_stats stat) {
 469  *      case LCK_DENIED:
 470  *              struct nlm_holder holder;
 471  *      default:
 472  *              void;
 473  *      };
 474  *
 475  *      struct nlm_testres {
 476  *              netobj cookie;
 477  *              nlm_testrply test_stat;
 478  *      };
 479  */
 480 static void encode_nlm_testrply(struct xdr_stream *xdr,
 481                                 const struct nlm_res *result)
 482 {
 483         if (result->status == nlm_lck_denied)
 484                 encode_nlm_holder(xdr, result);
 485 }
 486
 487 static void nlm_xdr_enc_testres(struct rpc_rqst *req,
 488                                 struct xdr_stream *xdr,
 489                                 const void *data)
 490 {
 491         const struct nlm_res *result = data;
 492
 493         encode_cookie(xdr, &result->cookie);
 494         encode_nlm_stat(xdr, result->status);
 495         encode_nlm_testrply(xdr, result);
 496 }
 497
 498
 499 /*
 500  * NLMv3 XDR decode functions
 501  *
 502  * NLMv3 result types are defined in Chapter 10 of The Open Group's
 503  * "Protocols for Interworking: XNFS, Version 3W".
 504  */
 505
 506 /*
 507  *      union nlm_testrply switch (nlm_stats stat) {
 508  *      case LCK_DENIED:
 509  *              struct nlm_holder holder;
 510  *      default:
 511  *              void;
 512  *      };
 513  *
 514  *      struct nlm_testres {
 515  *              netobj cookie;
 516  *              nlm_testrply test_stat;
 517  *      };
 518  */
 519 static int decode_nlm_testrply(struct xdr_stream *xdr,
 520                                struct nlm_res *result)
 521 {
 522         int error;
 523
 524         error = decode_nlm_stat(xdr, &result->status);
 525         if (unlikely(error))
 526                 goto out;
 527         if (result->status == nlm_lck_denied)
 528                 error = decode_nlm_holder(xdr, result);
 529 out:
 530         return error;
 531 }
 532
 533 static int nlm_xdr_dec_testres(struct rpc_rqst *req,
 534                                struct xdr_stream *xdr,
 535                                void *data)
 536 {
 537         struct nlm_res *result = data;
 538         int error;
 539
 540         error = decode_cookie(xdr, &result->cookie);
 541         if (unlikely(error))
 542                 goto out;
 543         error = decode_nlm_testrply(xdr, result);
 544 out:
 545         return error;
 546 }
 547
 548 /*
 549  *      struct nlm_res {
 550  *              netobj cookie;
 551  *              nlm_stat stat;
 552  *      };
 553  */
 554 static int nlm_xdr_dec_res(struct rpc_rqst *req,
 555                            struct xdr_stream *xdr,
 556                            void *data)
 557 {
 558         struct nlm_res *result = data;
 559         int error;
 560
 561         error = decode_cookie(xdr, &result->cookie);
 562         if (unlikely(error))
 563                 goto out;
 564         error = decode_nlm_stat(xdr, &result->status);
 565 out:
 566         return error;
 567 }
 568
 569
 570 /*
 571  * For NLM, a void procedure really returns nothing
 572  */
 573 #define nlm_xdr_dec_norep       NULL
 574
 575 #define PROC(proc, argtype, restype)    \
 576 [NLMPROC_##proc] = {                                                    \
 577         .p_proc      = NLMPROC_##proc,                                  \
 578         .p_encode    = nlm_xdr_enc_##argtype,           \
 579         .p_decode    = nlm_xdr_dec_##restype,                           \
 580         .p_arglen    = NLM_##argtype##_sz,                              \
 581         .p_replen    = NLM_##restype##_sz,                              \
 582         .p_statidx   = NLMPROC_##proc,                                  \
 583         .p_name      = #proc,                                           \
 584         }
 585
 586 static const struct rpc_procinfo nlm_procedures[] = {
 587         PROC(TEST,              testargs,       testres),
 588         PROC(LOCK,              lockargs,       res),
 589         PROC(CANCEL,            cancargs,       res),
 590         PROC(UNLOCK,            unlockargs,     res),
 591         PROC(GRANTED,           testargs,       res),
 592         PROC(TEST_MSG,          testargs,       norep),
 593         PROC(LOCK_MSG,          lockargs,       norep),
 594         PROC(CANCEL_MSG,        cancargs,       norep),
 595         PROC(UNLOCK_MSG,        unlockargs,     norep),
 596         PROC(GRANTED_MSG,       testargs,       norep),
 597         PROC(TEST_RES,          testres,        norep),
 598         PROC(LOCK_RES,          res,            norep),
 599         PROC(CANCEL_RES,        res,            norep),
 600         PROC(UNLOCK_RES,        res,            norep),
 601         PROC(GRANTED_RES,       res,            norep),
 602 };
 603
 604 static unsigned int nlm_version1_counts[ARRAY_SIZE(nlm_procedures)];
 605 static const struct rpc_version nlm_version1 = {
 606         .number         = 1,
 607         .nrprocs        = ARRAY_SIZE(nlm_procedures),
 608         .procs          = nlm_procedures,
 609         .counts         = nlm_version1_counts,
 610 };
 611
 612 static unsigned int nlm_version3_counts[ARRAY_SIZE(nlm_procedures)];
 613 static const struct rpc_version nlm_version3 = {
 614         .number         = 3,
 615         .nrprocs        = ARRAY_SIZE(nlm_procedures),
 616         .procs          = nlm_procedures,
 617         .counts         = nlm_version3_counts,
 618 };
 619
 620 static const struct rpc_version *nlm_versions[] = {
 621         [1] = &nlm_version1,
 622         [3] = &nlm_version3,
 623 #ifdef CONFIG_LOCKD_V4
 624         [4] = &nlm_version4,
 625 #endif
 626 };
 627
 628 static struct rpc_stat          nlm_rpc_stats;
 629
 630 const struct rpc_program        nlm_program = {
 631         .name           = "lockd",
 632         .number         = NLM_PROGRAM,
 633         .nrvers         = ARRAY_SIZE(nlm_versions),
 634         .version        = nlm_versions,
 635         .stats          = &nlm_rpc_stats,
 636 };