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