root/fs/nfs/mount_clnt.c

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DEFINITIONS

This source file includes following definitions.
  1. nfs_mount
  2. nfs_umount
  3. encode_mntdirpath
  4. mnt_xdr_enc_dirpath
  5. decode_status
  6. decode_fhandle
  7. mnt_xdr_dec_mountres
  8. decode_fhs_status
  9. decode_fhandle3
  10. decode_auth_flavors
  11. mnt_xdr_dec_mountres3

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * In-kernel MOUNT protocol client
   4  *
   5  * Copyright (C) 1997, Olaf Kirch <okir@monad.swb.de>
   6  */
   7 
   8 #include <linux/types.h>
   9 #include <linux/socket.h>
  10 #include <linux/kernel.h>
  11 #include <linux/errno.h>
  12 #include <linux/uio.h>
  13 #include <linux/net.h>
  14 #include <linux/in.h>
  15 #include <linux/sunrpc/clnt.h>
  16 #include <linux/sunrpc/sched.h>
  17 #include <linux/nfs_fs.h>
  18 #include "internal.h"
  19 
  20 #define NFSDBG_FACILITY NFSDBG_MOUNT
  21 
  22 /*
  23  * Defined by RFC 1094, section A.3; and RFC 1813, section 5.1.4
  24  */
  25 #define MNTPATHLEN              (1024)
  26 
  27 /*
  28  * XDR data type sizes
  29  */
  30 #define encode_dirpath_sz       (1 + XDR_QUADLEN(MNTPATHLEN))
  31 #define MNT_status_sz           (1)
  32 #define MNT_fhs_status_sz       (1)
  33 #define MNT_fhandle_sz          XDR_QUADLEN(NFS2_FHSIZE)
  34 #define MNT_fhandle3_sz         (1 + XDR_QUADLEN(NFS3_FHSIZE))
  35 #define MNT_fhandlev3_sz        XDR_QUADLEN(NFS3_FHSIZE)
  36 #define MNT_authflav3_sz        (1 + NFS_MAX_SECFLAVORS)
  37 
  38 /*
  39  * XDR argument and result sizes
  40  */
  41 #define MNT_enc_dirpath_sz      encode_dirpath_sz
  42 #define MNT_dec_mountres_sz     (MNT_status_sz + MNT_fhandle_sz)
  43 #define MNT_dec_mountres3_sz    (MNT_status_sz + MNT_fhandlev3_sz + \
  44                                  MNT_authflav3_sz)
  45 
  46 /*
  47  * Defined by RFC 1094, section A.5
  48  */
  49 enum {
  50         MOUNTPROC_NULL          = 0,
  51         MOUNTPROC_MNT           = 1,
  52         MOUNTPROC_DUMP          = 2,
  53         MOUNTPROC_UMNT          = 3,
  54         MOUNTPROC_UMNTALL       = 4,
  55         MOUNTPROC_EXPORT        = 5,
  56 };
  57 
  58 /*
  59  * Defined by RFC 1813, section 5.2
  60  */
  61 enum {
  62         MOUNTPROC3_NULL         = 0,
  63         MOUNTPROC3_MNT          = 1,
  64         MOUNTPROC3_DUMP         = 2,
  65         MOUNTPROC3_UMNT         = 3,
  66         MOUNTPROC3_UMNTALL      = 4,
  67         MOUNTPROC3_EXPORT       = 5,
  68 };
  69 
  70 static const struct rpc_program mnt_program;
  71 
  72 /*
  73  * Defined by OpenGroup XNFS Version 3W, chapter 8
  74  */
  75 enum mountstat {
  76         MNT_OK                  = 0,
  77         MNT_EPERM               = 1,
  78         MNT_ENOENT              = 2,
  79         MNT_EACCES              = 13,
  80         MNT_EINVAL              = 22,
  81 };
  82 
  83 static struct {
  84         u32 status;
  85         int errno;
  86 } mnt_errtbl[] = {
  87         { .status = MNT_OK,                     .errno = 0,             },
  88         { .status = MNT_EPERM,                  .errno = -EPERM,        },
  89         { .status = MNT_ENOENT,                 .errno = -ENOENT,       },
  90         { .status = MNT_EACCES,                 .errno = -EACCES,       },
  91         { .status = MNT_EINVAL,                 .errno = -EINVAL,       },
  92 };
  93 
  94 /*
  95  * Defined by RFC 1813, section 5.1.5
  96  */
  97 enum mountstat3 {
  98         MNT3_OK                 = 0,            /* no error */
  99         MNT3ERR_PERM            = 1,            /* Not owner */
 100         MNT3ERR_NOENT           = 2,            /* No such file or directory */
 101         MNT3ERR_IO              = 5,            /* I/O error */
 102         MNT3ERR_ACCES           = 13,           /* Permission denied */
 103         MNT3ERR_NOTDIR          = 20,           /* Not a directory */
 104         MNT3ERR_INVAL           = 22,           /* Invalid argument */
 105         MNT3ERR_NAMETOOLONG     = 63,           /* Filename too long */
 106         MNT3ERR_NOTSUPP         = 10004,        /* Operation not supported */
 107         MNT3ERR_SERVERFAULT     = 10006,        /* A failure on the server */
 108 };
 109 
 110 static struct {
 111         u32 status;
 112         int errno;
 113 } mnt3_errtbl[] = {
 114         { .status = MNT3_OK,                    .errno = 0,             },
 115         { .status = MNT3ERR_PERM,               .errno = -EPERM,        },
 116         { .status = MNT3ERR_NOENT,              .errno = -ENOENT,       },
 117         { .status = MNT3ERR_IO,                 .errno = -EIO,          },
 118         { .status = MNT3ERR_ACCES,              .errno = -EACCES,       },
 119         { .status = MNT3ERR_NOTDIR,             .errno = -ENOTDIR,      },
 120         { .status = MNT3ERR_INVAL,              .errno = -EINVAL,       },
 121         { .status = MNT3ERR_NAMETOOLONG,        .errno = -ENAMETOOLONG, },
 122         { .status = MNT3ERR_NOTSUPP,            .errno = -ENOTSUPP,     },
 123         { .status = MNT3ERR_SERVERFAULT,        .errno = -EREMOTEIO,    },
 124 };
 125 
 126 struct mountres {
 127         int errno;
 128         struct nfs_fh *fh;
 129         unsigned int *auth_count;
 130         rpc_authflavor_t *auth_flavors;
 131 };
 132 
 133 struct mnt_fhstatus {
 134         u32 status;
 135         struct nfs_fh *fh;
 136 };
 137 
 138 /**
 139  * nfs_mount - Obtain an NFS file handle for the given host and path
 140  * @info: pointer to mount request arguments
 141  *
 142  * Uses default timeout parameters specified by underlying transport. On
 143  * successful return, the auth_flavs list and auth_flav_len will be populated
 144  * with the list from the server or a faked-up list if the server didn't
 145  * provide one.
 146  */
 147 int nfs_mount(struct nfs_mount_request *info)
 148 {
 149         struct mountres result = {
 150                 .fh             = info->fh,
 151                 .auth_count     = info->auth_flav_len,
 152                 .auth_flavors   = info->auth_flavs,
 153         };
 154         struct rpc_message msg  = {
 155                 .rpc_argp       = info->dirpath,
 156                 .rpc_resp       = &result,
 157         };
 158         struct rpc_create_args args = {
 159                 .net            = info->net,
 160                 .protocol       = info->protocol,
 161                 .address        = info->sap,
 162                 .addrsize       = info->salen,
 163                 .servername     = info->hostname,
 164                 .program        = &mnt_program,
 165                 .version        = info->version,
 166                 .authflavor     = RPC_AUTH_UNIX,
 167                 .cred           = current_cred(),
 168         };
 169         struct rpc_clnt         *mnt_clnt;
 170         int                     status;
 171 
 172         dprintk("NFS: sending MNT request for %s:%s\n",
 173                 (info->hostname ? info->hostname : "server"),
 174                         info->dirpath);
 175 
 176         if (strlen(info->dirpath) > MNTPATHLEN)
 177                 return -ENAMETOOLONG;
 178 
 179         if (info->noresvport)
 180                 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 181 
 182         mnt_clnt = rpc_create(&args);
 183         if (IS_ERR(mnt_clnt))
 184                 goto out_clnt_err;
 185 
 186         if (info->version == NFS_MNT3_VERSION)
 187                 msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC3_MNT];
 188         else
 189                 msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC_MNT];
 190 
 191         status = rpc_call_sync(mnt_clnt, &msg, RPC_TASK_SOFT|RPC_TASK_TIMEOUT);
 192         rpc_shutdown_client(mnt_clnt);
 193 
 194         if (status < 0)
 195                 goto out_call_err;
 196         if (result.errno != 0)
 197                 goto out_mnt_err;
 198 
 199         dprintk("NFS: MNT request succeeded\n");
 200         status = 0;
 201 
 202         /*
 203          * If the server didn't provide a flavor list, allow the
 204          * client to try any flavor.
 205          */
 206         if (info->version != NFS_MNT3_VERSION || *info->auth_flav_len == 0) {
 207                 dprintk("NFS: Faking up auth_flavs list\n");
 208                 info->auth_flavs[0] = RPC_AUTH_NULL;
 209                 *info->auth_flav_len = 1;
 210         }
 211 out:
 212         return status;
 213 
 214 out_clnt_err:
 215         status = PTR_ERR(mnt_clnt);
 216         dprintk("NFS: failed to create MNT RPC client, status=%d\n", status);
 217         goto out;
 218 
 219 out_call_err:
 220         dprintk("NFS: MNT request failed, status=%d\n", status);
 221         goto out;
 222 
 223 out_mnt_err:
 224         dprintk("NFS: MNT server returned result %d\n", result.errno);
 225         status = result.errno;
 226         goto out;
 227 }
 228 
 229 /**
 230  * nfs_umount - Notify a server that we have unmounted this export
 231  * @info: pointer to umount request arguments
 232  *
 233  * MOUNTPROC_UMNT is advisory, so we set a short timeout, and always
 234  * use UDP.
 235  */
 236 void nfs_umount(const struct nfs_mount_request *info)
 237 {
 238         static const struct rpc_timeout nfs_umnt_timeout = {
 239                 .to_initval = 1 * HZ,
 240                 .to_maxval = 3 * HZ,
 241                 .to_retries = 2,
 242         };
 243         struct rpc_create_args args = {
 244                 .net            = info->net,
 245                 .protocol       = IPPROTO_UDP,
 246                 .address        = info->sap,
 247                 .addrsize       = info->salen,
 248                 .timeout        = &nfs_umnt_timeout,
 249                 .servername     = info->hostname,
 250                 .program        = &mnt_program,
 251                 .version        = info->version,
 252                 .authflavor     = RPC_AUTH_UNIX,
 253                 .flags          = RPC_CLNT_CREATE_NOPING,
 254                 .cred           = current_cred(),
 255         };
 256         struct rpc_message msg  = {
 257                 .rpc_argp       = info->dirpath,
 258         };
 259         struct rpc_clnt *clnt;
 260         int status;
 261 
 262         if (strlen(info->dirpath) > MNTPATHLEN)
 263                 return;
 264 
 265         if (info->noresvport)
 266                 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 267 
 268         clnt = rpc_create(&args);
 269         if (IS_ERR(clnt))
 270                 goto out_clnt_err;
 271 
 272         dprintk("NFS: sending UMNT request for %s:%s\n",
 273                 (info->hostname ? info->hostname : "server"), info->dirpath);
 274 
 275         if (info->version == NFS_MNT3_VERSION)
 276                 msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC3_UMNT];
 277         else
 278                 msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC_UMNT];
 279 
 280         status = rpc_call_sync(clnt, &msg, 0);
 281         rpc_shutdown_client(clnt);
 282 
 283         if (unlikely(status < 0))
 284                 goto out_call_err;
 285 
 286         return;
 287 
 288 out_clnt_err:
 289         dprintk("NFS: failed to create UMNT RPC client, status=%ld\n",
 290                         PTR_ERR(clnt));
 291         return;
 292 
 293 out_call_err:
 294         dprintk("NFS: UMNT request failed, status=%d\n", status);
 295 }
 296 
 297 /*
 298  * XDR encode/decode functions for MOUNT
 299  */
 300 
 301 static void encode_mntdirpath(struct xdr_stream *xdr, const char *pathname)
 302 {
 303         const u32 pathname_len = strlen(pathname);
 304         __be32 *p;
 305 
 306         p = xdr_reserve_space(xdr, 4 + pathname_len);
 307         xdr_encode_opaque(p, pathname, pathname_len);
 308 }
 309 
 310 static void mnt_xdr_enc_dirpath(struct rpc_rqst *req, struct xdr_stream *xdr,
 311                                 const void *dirpath)
 312 {
 313         encode_mntdirpath(xdr, dirpath);
 314 }
 315 
 316 /*
 317  * RFC 1094: "A non-zero status indicates some sort of error.  In this
 318  * case, the status is a UNIX error number."  This can be problematic
 319  * if the server and client use different errno values for the same
 320  * error.
 321  *
 322  * However, the OpenGroup XNFS spec provides a simple mapping that is
 323  * independent of local errno values on the server and the client.
 324  */
 325 static int decode_status(struct xdr_stream *xdr, struct mountres *res)
 326 {
 327         unsigned int i;
 328         u32 status;
 329         __be32 *p;
 330 
 331         p = xdr_inline_decode(xdr, 4);
 332         if (unlikely(p == NULL))
 333                 return -EIO;
 334         status = be32_to_cpup(p);
 335 
 336         for (i = 0; i < ARRAY_SIZE(mnt_errtbl); i++) {
 337                 if (mnt_errtbl[i].status == status) {
 338                         res->errno = mnt_errtbl[i].errno;
 339                         return 0;
 340                 }
 341         }
 342 
 343         dprintk("NFS: unrecognized MNT status code: %u\n", status);
 344         res->errno = -EACCES;
 345         return 0;
 346 }
 347 
 348 static int decode_fhandle(struct xdr_stream *xdr, struct mountres *res)
 349 {
 350         struct nfs_fh *fh = res->fh;
 351         __be32 *p;
 352 
 353         p = xdr_inline_decode(xdr, NFS2_FHSIZE);
 354         if (unlikely(p == NULL))
 355                 return -EIO;
 356 
 357         fh->size = NFS2_FHSIZE;
 358         memcpy(fh->data, p, NFS2_FHSIZE);
 359         return 0;
 360 }
 361 
 362 static int mnt_xdr_dec_mountres(struct rpc_rqst *req,
 363                                 struct xdr_stream *xdr,
 364                                 void *data)
 365 {
 366         struct mountres *res = data;
 367         int status;
 368 
 369         status = decode_status(xdr, res);
 370         if (unlikely(status != 0 || res->errno != 0))
 371                 return status;
 372         return decode_fhandle(xdr, res);
 373 }
 374 
 375 static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
 376 {
 377         unsigned int i;
 378         u32 status;
 379         __be32 *p;
 380 
 381         p = xdr_inline_decode(xdr, 4);
 382         if (unlikely(p == NULL))
 383                 return -EIO;
 384         status = be32_to_cpup(p);
 385 
 386         for (i = 0; i < ARRAY_SIZE(mnt3_errtbl); i++) {
 387                 if (mnt3_errtbl[i].status == status) {
 388                         res->errno = mnt3_errtbl[i].errno;
 389                         return 0;
 390                 }
 391         }
 392 
 393         dprintk("NFS: unrecognized MNT3 status code: %u\n", status);
 394         res->errno = -EACCES;
 395         return 0;
 396 }
 397 
 398 static int decode_fhandle3(struct xdr_stream *xdr, struct mountres *res)
 399 {
 400         struct nfs_fh *fh = res->fh;
 401         u32 size;
 402         __be32 *p;
 403 
 404         p = xdr_inline_decode(xdr, 4);
 405         if (unlikely(p == NULL))
 406                 return -EIO;
 407 
 408         size = be32_to_cpup(p);
 409         if (size > NFS3_FHSIZE || size == 0)
 410                 return -EIO;
 411 
 412         p = xdr_inline_decode(xdr, size);
 413         if (unlikely(p == NULL))
 414                 return -EIO;
 415 
 416         fh->size = size;
 417         memcpy(fh->data, p, size);
 418         return 0;
 419 }
 420 
 421 static int decode_auth_flavors(struct xdr_stream *xdr, struct mountres *res)
 422 {
 423         rpc_authflavor_t *flavors = res->auth_flavors;
 424         unsigned int *count = res->auth_count;
 425         u32 entries, i;
 426         __be32 *p;
 427 
 428         if (*count == 0)
 429                 return 0;
 430 
 431         p = xdr_inline_decode(xdr, 4);
 432         if (unlikely(p == NULL))
 433                 return -EIO;
 434         entries = be32_to_cpup(p);
 435         dprintk("NFS: received %u auth flavors\n", entries);
 436         if (entries > NFS_MAX_SECFLAVORS)
 437                 entries = NFS_MAX_SECFLAVORS;
 438 
 439         p = xdr_inline_decode(xdr, 4 * entries);
 440         if (unlikely(p == NULL))
 441                 return -EIO;
 442 
 443         if (entries > *count)
 444                 entries = *count;
 445 
 446         for (i = 0; i < entries; i++) {
 447                 flavors[i] = be32_to_cpup(p++);
 448                 dprintk("NFS:   auth flavor[%u]: %d\n", i, flavors[i]);
 449         }
 450         *count = i;
 451 
 452         return 0;
 453 }
 454 
 455 static int mnt_xdr_dec_mountres3(struct rpc_rqst *req,
 456                                  struct xdr_stream *xdr,
 457                                  void *data)
 458 {
 459         struct mountres *res = data;
 460         int status;
 461 
 462         status = decode_fhs_status(xdr, res);
 463         if (unlikely(status != 0 || res->errno != 0))
 464                 return status;
 465         status = decode_fhandle3(xdr, res);
 466         if (unlikely(status != 0)) {
 467                 res->errno = -EBADHANDLE;
 468                 return 0;
 469         }
 470         return decode_auth_flavors(xdr, res);
 471 }
 472 
 473 static const struct rpc_procinfo mnt_procedures[] = {
 474         [MOUNTPROC_MNT] = {
 475                 .p_proc         = MOUNTPROC_MNT,
 476                 .p_encode       = mnt_xdr_enc_dirpath,
 477                 .p_decode       = mnt_xdr_dec_mountres,
 478                 .p_arglen       = MNT_enc_dirpath_sz,
 479                 .p_replen       = MNT_dec_mountres_sz,
 480                 .p_statidx      = MOUNTPROC_MNT,
 481                 .p_name         = "MOUNT",
 482         },
 483         [MOUNTPROC_UMNT] = {
 484                 .p_proc         = MOUNTPROC_UMNT,
 485                 .p_encode       = mnt_xdr_enc_dirpath,
 486                 .p_arglen       = MNT_enc_dirpath_sz,
 487                 .p_statidx      = MOUNTPROC_UMNT,
 488                 .p_name         = "UMOUNT",
 489         },
 490 };
 491 
 492 static const struct rpc_procinfo mnt3_procedures[] = {
 493         [MOUNTPROC3_MNT] = {
 494                 .p_proc         = MOUNTPROC3_MNT,
 495                 .p_encode       = mnt_xdr_enc_dirpath,
 496                 .p_decode       = mnt_xdr_dec_mountres3,
 497                 .p_arglen       = MNT_enc_dirpath_sz,
 498                 .p_replen       = MNT_dec_mountres3_sz,
 499                 .p_statidx      = MOUNTPROC3_MNT,
 500                 .p_name         = "MOUNT",
 501         },
 502         [MOUNTPROC3_UMNT] = {
 503                 .p_proc         = MOUNTPROC3_UMNT,
 504                 .p_encode       = mnt_xdr_enc_dirpath,
 505                 .p_arglen       = MNT_enc_dirpath_sz,
 506                 .p_statidx      = MOUNTPROC3_UMNT,
 507                 .p_name         = "UMOUNT",
 508         },
 509 };
 510 
 511 static unsigned int mnt_counts[ARRAY_SIZE(mnt_procedures)];
 512 static const struct rpc_version mnt_version1 = {
 513         .number         = 1,
 514         .nrprocs        = ARRAY_SIZE(mnt_procedures),
 515         .procs          = mnt_procedures,
 516         .counts         = mnt_counts,
 517 };
 518 
 519 static unsigned int mnt3_counts[ARRAY_SIZE(mnt3_procedures)];
 520 static const struct rpc_version mnt_version3 = {
 521         .number         = 3,
 522         .nrprocs        = ARRAY_SIZE(mnt3_procedures),
 523         .procs          = mnt3_procedures,
 524         .counts         = mnt3_counts,
 525 };
 526 
 527 static const struct rpc_version *mnt_version[] = {
 528         NULL,
 529         &mnt_version1,
 530         NULL,
 531         &mnt_version3,
 532 };
 533 
 534 static struct rpc_stat mnt_stats;
 535 
 536 static const struct rpc_program mnt_program = {
 537         .name           = "mount",
 538         .number         = NFS_MNT_PROGRAM,
 539         .nrvers         = ARRAY_SIZE(mnt_version),
 540         .version        = mnt_version,
 541         .stats          = &mnt_stats,
 542 };

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