fs/nfs/mount_clnt.c

   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_authflav3_sz        (1 + NFS_MAX_SECFLAVORS)
  36
  37 /*
  38  * XDR argument and result sizes
  39  */
  40 #define MNT_enc_dirpath_sz      encode_dirpath_sz
  41 #define MNT_dec_mountres_sz     (MNT_status_sz + MNT_fhandle_sz)
  42 #define MNT_dec_mountres3_sz    (MNT_status_sz + MNT_fhandle_sz + \
  43                                  MNT_authflav3_sz)
  44
  45 /*
  46  * Defined by RFC 1094, section A.5
  47  */
  48 enum {
  49         MOUNTPROC_NULL          = 0,
  50         MOUNTPROC_MNT           = 1,
  51         MOUNTPROC_DUMP          = 2,
  52         MOUNTPROC_UMNT          = 3,
  53         MOUNTPROC_UMNTALL       = 4,
  54         MOUNTPROC_EXPORT        = 5,
  55 };
  56
  57 /*
  58  * Defined by RFC 1813, section 5.2
  59  */
  60 enum {
  61         MOUNTPROC3_NULL         = 0,
  62         MOUNTPROC3_MNT          = 1,
  63         MOUNTPROC3_DUMP         = 2,
  64         MOUNTPROC3_UMNT         = 3,
  65         MOUNTPROC3_UMNTALL      = 4,
  66         MOUNTPROC3_EXPORT       = 5,
  67 };
  68
  69 static const struct rpc_program mnt_program;
  70
  71 /*
  72  * Defined by OpenGroup XNFS Version 3W, chapter 8
  73  */
  74 enum mountstat {
  75         MNT_OK                  = 0,
  76         MNT_EPERM               = 1,
  77         MNT_ENOENT              = 2,
  78         MNT_EACCES              = 13,
  79         MNT_EINVAL              = 22,
  80 };
  81
  82 static struct {
  83         u32 status;
  84         int errno;
  85 } mnt_errtbl[] = {
  86         { .status = MNT_OK,                     .errno = 0,             },
  87         { .status = MNT_EPERM,                  .errno = -EPERM,        },
  88         { .status = MNT_ENOENT,                 .errno = -ENOENT,       },
  89         { .status = MNT_EACCES,                 .errno = -EACCES,       },
  90         { .status = MNT_EINVAL,                 .errno = -EINVAL,       },
  91 };
  92
  93 /*
  94  * Defined by RFC 1813, section 5.1.5
  95  */
  96 enum mountstat3 {
  97         MNT3_OK                 = 0,            /* no error */
  98         MNT3ERR_PERM            = 1,            /* Not owner */
  99         MNT3ERR_NOENT           = 2,            /* No such file or directory */
 100         MNT3ERR_IO              = 5,            /* I/O error */
 101         MNT3ERR_ACCES           = 13,           /* Permission denied */
 102         MNT3ERR_NOTDIR          = 20,           /* Not a directory */
 103         MNT3ERR_INVAL           = 22,           /* Invalid argument */
 104         MNT3ERR_NAMETOOLONG     = 63,           /* Filename too long */
 105         MNT3ERR_NOTSUPP         = 10004,        /* Operation not supported */
 106         MNT3ERR_SERVERFAULT     = 10006,        /* A failure on the server */
 107 };
 108
 109 static struct {
 110         u32 status;
 111         int errno;
 112 } mnt3_errtbl[] = {
 113         { .status = MNT3_OK,                    .errno = 0,             },
 114         { .status = MNT3ERR_PERM,               .errno = -EPERM,        },
 115         { .status = MNT3ERR_NOENT,              .errno = -ENOENT,       },
 116         { .status = MNT3ERR_IO,                 .errno = -EIO,          },
 117         { .status = MNT3ERR_ACCES,              .errno = -EACCES,       },
 118         { .status = MNT3ERR_NOTDIR,             .errno = -ENOTDIR,      },
 119         { .status = MNT3ERR_INVAL,              .errno = -EINVAL,       },
 120         { .status = MNT3ERR_NAMETOOLONG,        .errno = -ENAMETOOLONG, },
 121         { .status = MNT3ERR_NOTSUPP,            .errno = -ENOTSUPP,     },
 122         { .status = MNT3ERR_SERVERFAULT,        .errno = -EREMOTEIO,    },
 123 };
 124
 125 struct mountres {
 126         int errno;
 127         struct nfs_fh *fh;
 128         unsigned int *auth_count;
 129         rpc_authflavor_t *auth_flavors;
 130 };
 131
 132 struct mnt_fhstatus {
 133         u32 status;
 134         struct nfs_fh *fh;
 135 };
 136
 137 /**
 138  * nfs_mount - Obtain an NFS file handle for the given host and path
 139  * @info: pointer to mount request arguments
 140  *
 141  * Uses default timeout parameters specified by underlying transport. On
 142  * successful return, the auth_flavs list and auth_flav_len will be populated
 143  * with the list from the server or a faked-up list if the server didn't
 144  * provide one.
 145  */
 146 int nfs_mount(struct nfs_mount_request *info)
 147 {
 148         struct mountres result = {
 149                 .fh             = info->fh,
 150                 .auth_count     = info->auth_flav_len,
 151                 .auth_flavors   = info->auth_flavs,
 152         };
 153         struct rpc_message msg  = {
 154                 .rpc_argp       = info->dirpath,
 155                 .rpc_resp       = &result,
 156         };
 157         struct rpc_create_args args = {
 158                 .net            = info->net,
 159                 .protocol       = info->protocol,
 160                 .address        = info->sap,
 161                 .addrsize       = info->salen,
 162                 .servername     = info->hostname,
 163                 .program        = &mnt_program,
 164                 .version        = info->version,
 165                 .authflavor     = RPC_AUTH_UNIX,
 166                 .cred           = current_cred(),
 167         };
 168         struct rpc_clnt         *mnt_clnt;
 169         int                     status;
 170
 171         dprintk("NFS: sending MNT request for %s:%s\n",
 172                 (info->hostname ? info->hostname : "server"),
 173                         info->dirpath);
 174
 175         if (strlen(info->dirpath) > MNTPATHLEN)
 176                 return -ENAMETOOLONG;
 177
 178         if (info->noresvport)
 179                 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 180
 181         mnt_clnt = rpc_create(&args);
 182         if (IS_ERR(mnt_clnt))
 183                 goto out_clnt_err;
 184
 185         if (info->version == NFS_MNT3_VERSION)
 186                 msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC3_MNT];
 187         else
 188                 msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC_MNT];
 189
 190         status = rpc_call_sync(mnt_clnt, &msg, RPC_TASK_SOFT|RPC_TASK_TIMEOUT);
 191         rpc_shutdown_client(mnt_clnt);
 192
 193         if (status < 0)
 194                 goto out_call_err;
 195         if (result.errno != 0)
 196                 goto out_mnt_err;
 197
 198         dprintk("NFS: MNT request succeeded\n");
 199         status = 0;
 200
 201         /*
 202          * If the server didn't provide a flavor list, allow the
 203          * client to try any flavor.
 204          */
 205         if (info->version != NFS_MNT3_VERSION || *info->auth_flav_len == 0) {
 206                 dprintk("NFS: Faking up auth_flavs list\n");
 207                 info->auth_flavs[0] = RPC_AUTH_NULL;
 208                 *info->auth_flav_len = 1;
 209         }
 210 out:
 211         return status;
 212
 213 out_clnt_err:
 214         status = PTR_ERR(mnt_clnt);
 215         dprintk("NFS: failed to create MNT RPC client, status=%d\n", status);
 216         goto out;
 217
 218 out_call_err:
 219         dprintk("NFS: MNT request failed, status=%d\n", status);
 220         goto out;
 221
 222 out_mnt_err:
 223         dprintk("NFS: MNT server returned result %d\n", result.errno);
 224         status = result.errno;
 225         goto out;
 226 }
 227
 228 /**
 229  * nfs_umount - Notify a server that we have unmounted this export
 230  * @info: pointer to umount request arguments
 231  *
 232  * MOUNTPROC_UMNT is advisory, so we set a short timeout, and always
 233  * use UDP.
 234  */
 235 void nfs_umount(const struct nfs_mount_request *info)
 236 {
 237         static const struct rpc_timeout nfs_umnt_timeout = {
 238                 .to_initval = 1 * HZ,
 239                 .to_maxval = 3 * HZ,
 240                 .to_retries = 2,
 241         };
 242         struct rpc_create_args args = {
 243                 .net            = info->net,
 244                 .protocol       = IPPROTO_UDP,
 245                 .address        = info->sap,
 246                 .addrsize       = info->salen,
 247                 .timeout        = &nfs_umnt_timeout,
 248                 .servername     = info->hostname,
 249                 .program        = &mnt_program,
 250                 .version        = info->version,
 251                 .authflavor     = RPC_AUTH_UNIX,
 252                 .flags          = RPC_CLNT_CREATE_NOPING,
 253                 .cred           = current_cred(),
 254         };
 255         struct rpc_message msg  = {
 256                 .rpc_argp       = info->dirpath,
 257         };
 258         struct rpc_clnt *clnt;
 259         int status;
 260
 261         if (strlen(info->dirpath) > MNTPATHLEN)
 262                 return;
 263
 264         if (info->noresvport)
 265                 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 266
 267         clnt = rpc_create(&args);
 268         if (IS_ERR(clnt))
 269                 goto out_clnt_err;
 270
 271         dprintk("NFS: sending UMNT request for %s:%s\n",
 272                 (info->hostname ? info->hostname : "server"), info->dirpath);
 273
 274         if (info->version == NFS_MNT3_VERSION)
 275                 msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC3_UMNT];
 276         else
 277                 msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC_UMNT];
 278
 279         status = rpc_call_sync(clnt, &msg, 0);
 280         rpc_shutdown_client(clnt);
 281
 282         if (unlikely(status < 0))
 283                 goto out_call_err;
 284
 285         return;
 286
 287 out_clnt_err:
 288         dprintk("NFS: failed to create UMNT RPC client, status=%ld\n",
 289                         PTR_ERR(clnt));
 290         return;
 291
 292 out_call_err:
 293         dprintk("NFS: UMNT request failed, status=%d\n", status);
 294 }
 295
 296 /*
 297  * XDR encode/decode functions for MOUNT
 298  */
 299
 300 static void encode_mntdirpath(struct xdr_stream *xdr, const char *pathname)
 301 {
 302         const u32 pathname_len = strlen(pathname);
 303         __be32 *p;
 304
 305         p = xdr_reserve_space(xdr, 4 + pathname_len);
 306         xdr_encode_opaque(p, pathname, pathname_len);
 307 }
 308
 309 static void mnt_xdr_enc_dirpath(struct rpc_rqst *req, struct xdr_stream *xdr,
 310                                 const void *dirpath)
 311 {
 312         encode_mntdirpath(xdr, dirpath);
 313 }
 314
 315 /*
 316  * RFC 1094: "A non-zero status indicates some sort of error.  In this
 317  * case, the status is a UNIX error number."  This can be problematic
 318  * if the server and client use different errno values for the same
 319  * error.
 320  *
 321  * However, the OpenGroup XNFS spec provides a simple mapping that is
 322  * independent of local errno values on the server and the client.
 323  */
 324 static int decode_status(struct xdr_stream *xdr, struct mountres *res)
 325 {
 326         unsigned int i;
 327         u32 status;
 328         __be32 *p;
 329
 330         p = xdr_inline_decode(xdr, 4);
 331         if (unlikely(p == NULL))
 332                 return -EIO;
 333         status = be32_to_cpup(p);
 334
 335         for (i = 0; i < ARRAY_SIZE(mnt_errtbl); i++) {
 336                 if (mnt_errtbl[i].status == status) {
 337                         res->errno = mnt_errtbl[i].errno;
 338                         return 0;
 339                 }
 340         }
 341
 342         dprintk("NFS: unrecognized MNT status code: %u\n", status);
 343         res->errno = -EACCES;
 344         return 0;
 345 }
 346
 347 static int decode_fhandle(struct xdr_stream *xdr, struct mountres *res)
 348 {
 349         struct nfs_fh *fh = res->fh;
 350         __be32 *p;
 351
 352         p = xdr_inline_decode(xdr, NFS2_FHSIZE);
 353         if (unlikely(p == NULL))
 354                 return -EIO;
 355
 356         fh->size = NFS2_FHSIZE;
 357         memcpy(fh->data, p, NFS2_FHSIZE);
 358         return 0;
 359 }
 360
 361 static int mnt_xdr_dec_mountres(struct rpc_rqst *req,
 362                                 struct xdr_stream *xdr,
 363                                 void *data)
 364 {
 365         struct mountres *res = data;
 366         int status;
 367
 368         status = decode_status(xdr, res);
 369         if (unlikely(status != 0 || res->errno != 0))
 370                 return status;
 371         return decode_fhandle(xdr, res);
 372 }
 373
 374 static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
 375 {
 376         unsigned int i;
 377         u32 status;
 378         __be32 *p;
 379
 380         p = xdr_inline_decode(xdr, 4);
 381         if (unlikely(p == NULL))
 382                 return -EIO;
 383         status = be32_to_cpup(p);
 384
 385         for (i = 0; i < ARRAY_SIZE(mnt3_errtbl); i++) {
 386                 if (mnt3_errtbl[i].status == status) {
 387                         res->errno = mnt3_errtbl[i].errno;
 388                         return 0;
 389                 }
 390         }
 391
 392         dprintk("NFS: unrecognized MNT3 status code: %u\n", status);
 393         res->errno = -EACCES;
 394         return 0;
 395 }
 396
 397 static int decode_fhandle3(struct xdr_stream *xdr, struct mountres *res)
 398 {
 399         struct nfs_fh *fh = res->fh;
 400         u32 size;
 401         __be32 *p;
 402
 403         p = xdr_inline_decode(xdr, 4);
 404         if (unlikely(p == NULL))
 405                 return -EIO;
 406
 407         size = be32_to_cpup(p);
 408         if (size > NFS3_FHSIZE || size == 0)
 409                 return -EIO;
 410
 411         p = xdr_inline_decode(xdr, size);
 412         if (unlikely(p == NULL))
 413                 return -EIO;
 414
 415         fh->size = size;
 416         memcpy(fh->data, p, size);
 417         return 0;
 418 }
 419
 420 static int decode_auth_flavors(struct xdr_stream *xdr, struct mountres *res)
 421 {
 422         rpc_authflavor_t *flavors = res->auth_flavors;
 423         unsigned int *count = res->auth_count;
 424         u32 entries, i;
 425         __be32 *p;
 426
 427         if (*count == 0)
 428                 return 0;
 429
 430         p = xdr_inline_decode(xdr, 4);
 431         if (unlikely(p == NULL))
 432                 return -EIO;
 433         entries = be32_to_cpup(p);
 434         dprintk("NFS: received %u auth flavors\n", entries);
 435         if (entries > NFS_MAX_SECFLAVORS)
 436                 entries = NFS_MAX_SECFLAVORS;
 437
 438         p = xdr_inline_decode(xdr, 4 * entries);
 439         if (unlikely(p == NULL))
 440                 return -EIO;
 441
 442         if (entries > *count)
 443                 entries = *count;
 444
 445         for (i = 0; i < entries; i++) {
 446                 flavors[i] = be32_to_cpup(p++);
 447                 dprintk("NFS:   auth flavor[%u]: %d\n", i, flavors[i]);
 448         }
 449         *count = i;
 450
 451         return 0;
 452 }
 453
 454 static int mnt_xdr_dec_mountres3(struct rpc_rqst *req,
 455                                  struct xdr_stream *xdr,
 456                                  void *data)
 457 {
 458         struct mountres *res = data;
 459         int status;
 460
 461         status = decode_fhs_status(xdr, res);
 462         if (unlikely(status != 0 || res->errno != 0))
 463                 return status;
 464         status = decode_fhandle3(xdr, res);
 465         if (unlikely(status != 0)) {
 466                 res->errno = -EBADHANDLE;
 467                 return 0;
 468         }
 469         return decode_auth_flavors(xdr, res);
 470 }
 471
 472 static const struct rpc_procinfo mnt_procedures[] = {
 473         [MOUNTPROC_MNT] = {
 474                 .p_proc         = MOUNTPROC_MNT,
 475                 .p_encode       = mnt_xdr_enc_dirpath,
 476                 .p_decode       = mnt_xdr_dec_mountres,
 477                 .p_arglen       = MNT_enc_dirpath_sz,
 478                 .p_replen       = MNT_dec_mountres_sz,
 479                 .p_statidx      = MOUNTPROC_MNT,
 480                 .p_name         = "MOUNT",
 481         },
 482         [MOUNTPROC_UMNT] = {
 483                 .p_proc         = MOUNTPROC_UMNT,
 484                 .p_encode       = mnt_xdr_enc_dirpath,
 485                 .p_arglen       = MNT_enc_dirpath_sz,
 486                 .p_statidx      = MOUNTPROC_UMNT,
 487                 .p_name         = "UMOUNT",
 488         },
 489 };
 490
 491 static const struct rpc_procinfo mnt3_procedures[] = {
 492         [MOUNTPROC3_MNT] = {
 493                 .p_proc         = MOUNTPROC3_MNT,
 494                 .p_encode       = mnt_xdr_enc_dirpath,
 495                 .p_decode       = mnt_xdr_dec_mountres3,
 496                 .p_arglen       = MNT_enc_dirpath_sz,
 497                 .p_replen       = MNT_dec_mountres3_sz,
 498                 .p_statidx      = MOUNTPROC3_MNT,
 499                 .p_name         = "MOUNT",
 500         },
 501         [MOUNTPROC3_UMNT] = {
 502                 .p_proc         = MOUNTPROC3_UMNT,
 503                 .p_encode       = mnt_xdr_enc_dirpath,
 504                 .p_arglen       = MNT_enc_dirpath_sz,
 505                 .p_statidx      = MOUNTPROC3_UMNT,
 506                 .p_name         = "UMOUNT",
 507         },
 508 };
 509
 510 static unsigned int mnt_counts[ARRAY_SIZE(mnt_procedures)];
 511 static const struct rpc_version mnt_version1 = {
 512         .number         = 1,
 513         .nrprocs        = ARRAY_SIZE(mnt_procedures),
 514         .procs          = mnt_procedures,
 515         .counts         = mnt_counts,
 516 };
 517
 518 static unsigned int mnt3_counts[ARRAY_SIZE(mnt3_procedures)];
 519 static const struct rpc_version mnt_version3 = {
 520         .number         = 3,
 521         .nrprocs        = ARRAY_SIZE(mnt3_procedures),
 522         .procs          = mnt3_procedures,
 523         .counts         = mnt3_counts,
 524 };
 525
 526 static const struct rpc_version *mnt_version[] = {
 527         NULL,
 528         &mnt_version1,
 529         NULL,
 530         &mnt_version3,
 531 };
 532
 533 static struct rpc_stat mnt_stats;
 534
 535 static const struct rpc_program mnt_program = {
 536         .name           = "mount",
 537         .number         = NFS_MNT_PROGRAM,
 538         .nrvers         = ARRAY_SIZE(mnt_version),
 539         .version        = mnt_version,
 540         .stats          = &mnt_stats,
 541 };