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_fhandlev3_sz        XDR_QUADLEN(NFS3_FHSIZE)
  34 #define MNT_authflav3_sz        (1 + NFS_MAX_SECFLAVORS)
  35
  36 /*
  37  * XDR argument and result sizes
  38  */
  39 #define MNT_enc_dirpath_sz      encode_dirpath_sz
  40 #define MNT_dec_mountres_sz     (MNT_status_sz + MNT_fhandle_sz)
  41 #define MNT_dec_mountres3_sz    (MNT_status_sz + MNT_fhandlev3_sz + \
  42                                  MNT_authflav3_sz)
  43
  44 /*
  45  * Defined by RFC 1094, section A.5
  46  */
  47 enum {
  48         MOUNTPROC_NULL          = 0,
  49         MOUNTPROC_MNT           = 1,
  50         MOUNTPROC_DUMP          = 2,
  51         MOUNTPROC_UMNT          = 3,
  52         MOUNTPROC_UMNTALL       = 4,
  53         MOUNTPROC_EXPORT        = 5,
  54 };
  55
  56 /*
  57  * Defined by RFC 1813, section 5.2
  58  */
  59 enum {
  60         MOUNTPROC3_NULL         = 0,
  61         MOUNTPROC3_MNT          = 1,
  62         MOUNTPROC3_DUMP         = 2,
  63         MOUNTPROC3_UMNT         = 3,
  64         MOUNTPROC3_UMNTALL      = 4,
  65         MOUNTPROC3_EXPORT       = 5,
  66 };
  67
  68 static const struct rpc_program mnt_program;
  69
  70 /*
  71  * Defined by OpenGroup XNFS Version 3W, chapter 8
  72  */
  73 enum mountstat {
  74         MNT_OK                  = 0,
  75         MNT_EPERM               = 1,
  76         MNT_ENOENT              = 2,
  77         MNT_EACCES              = 13,
  78         MNT_EINVAL              = 22,
  79 };
  80
  81 static struct {
  82         u32 status;
  83         int errno;
  84 } mnt_errtbl[] = {
  85         { .status = MNT_OK,                     .errno = 0,             },
  86         { .status = MNT_EPERM,                  .errno = -EPERM,        },
  87         { .status = MNT_ENOENT,                 .errno = -ENOENT,       },
  88         { .status = MNT_EACCES,                 .errno = -EACCES,       },
  89         { .status = MNT_EINVAL,                 .errno = -EINVAL,       },
  90 };
  91
  92 /*
  93  * Defined by RFC 1813, section 5.1.5
  94  */
  95 enum mountstat3 {
  96         MNT3_OK                 = 0,            /* no error */
  97         MNT3ERR_PERM            = 1,            /* Not owner */
  98         MNT3ERR_NOENT           = 2,            /* No such file or directory */
  99         MNT3ERR_IO              = 5,            /* I/O error */
 100         MNT3ERR_ACCES           = 13,           /* Permission denied */
 101         MNT3ERR_NOTDIR          = 20,           /* Not a directory */
 102         MNT3ERR_INVAL           = 22,           /* Invalid argument */
 103         MNT3ERR_NAMETOOLONG     = 63,           /* Filename too long */
 104         MNT3ERR_NOTSUPP         = 10004,        /* Operation not supported */
 105         MNT3ERR_SERVERFAULT     = 10006,        /* A failure on the server */
 106 };
 107
 108 static struct {
 109         u32 status;
 110         int errno;
 111 } mnt3_errtbl[] = {
 112         { .status = MNT3_OK,                    .errno = 0,             },
 113         { .status = MNT3ERR_PERM,               .errno = -EPERM,        },
 114         { .status = MNT3ERR_NOENT,              .errno = -ENOENT,       },
 115         { .status = MNT3ERR_IO,                 .errno = -EIO,          },
 116         { .status = MNT3ERR_ACCES,              .errno = -EACCES,       },
 117         { .status = MNT3ERR_NOTDIR,             .errno = -ENOTDIR,      },
 118         { .status = MNT3ERR_INVAL,              .errno = -EINVAL,       },
 119         { .status = MNT3ERR_NAMETOOLONG,        .errno = -ENAMETOOLONG, },
 120         { .status = MNT3ERR_NOTSUPP,            .errno = -ENOTSUPP,     },
 121         { .status = MNT3ERR_SERVERFAULT,        .errno = -EREMOTEIO,    },
 122 };
 123
 124 struct mountres {
 125         int errno;
 126         struct nfs_fh *fh;
 127         unsigned int *auth_count;
 128         rpc_authflavor_t *auth_flavors;
 129 };
 130
 131 struct mnt_fhstatus {
 132         u32 status;
 133         struct nfs_fh *fh;
 134 };
 135
 136 /**
 137  * nfs_mount - Obtain an NFS file handle for the given host and path
 138  * @info: pointer to mount request arguments
 139  *
 140  * Uses default timeout parameters specified by underlying transport. On
 141  * successful return, the auth_flavs list and auth_flav_len will be populated
 142  * with the list from the server or a faked-up list if the server didn't
 143  * provide one.
 144  */
 145 int nfs_mount(struct nfs_mount_request *info)
 146 {
 147         struct mountres result = {
 148                 .fh             = info->fh,
 149                 .auth_count     = info->auth_flav_len,
 150                 .auth_flavors   = info->auth_flavs,
 151         };
 152         struct rpc_message msg  = {
 153                 .rpc_argp       = info->dirpath,
 154                 .rpc_resp       = &result,
 155         };
 156         struct rpc_create_args args = {
 157                 .net            = info->net,
 158                 .protocol       = info->protocol,
 159                 .address        = info->sap,
 160                 .addrsize       = info->salen,
 161                 .servername     = info->hostname,
 162                 .program        = &mnt_program,
 163                 .version        = info->version,
 164                 .authflavor     = RPC_AUTH_UNIX,
 165                 .cred           = current_cred(),
 166         };
 167         struct rpc_clnt         *mnt_clnt;
 168         int                     status;
 169
 170         dprintk("NFS: sending MNT request for %s:%s\n",
 171                 (info->hostname ? info->hostname : "server"),
 172                         info->dirpath);
 173
 174         if (strlen(info->dirpath) > MNTPATHLEN)
 175                 return -ENAMETOOLONG;
 176
 177         if (info->noresvport)
 178                 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 179
 180         mnt_clnt = rpc_create(&args);
 181         if (IS_ERR(mnt_clnt))
 182                 goto out_clnt_err;
 183
 184         if (info->version == NFS_MNT3_VERSION)
 185                 msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC3_MNT];
 186         else
 187                 msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC_MNT];
 188
 189         status = rpc_call_sync(mnt_clnt, &msg, RPC_TASK_SOFT|RPC_TASK_TIMEOUT);
 190         rpc_shutdown_client(mnt_clnt);
 191
 192         if (status < 0)
 193                 goto out_call_err;
 194         if (result.errno != 0)
 195                 goto out_mnt_err;
 196
 197         dprintk("NFS: MNT request succeeded\n");
 198         status = 0;
 199
 200         /*
 201          * If the server didn't provide a flavor list, allow the
 202          * client to try any flavor.
 203          */
 204         if (info->version != NFS_MNT3_VERSION || *info->auth_flav_len == 0) {
 205                 dprintk("NFS: Faking up auth_flavs list\n");
 206                 info->auth_flavs[0] = RPC_AUTH_NULL;
 207                 *info->auth_flav_len = 1;
 208         }
 209 out:
 210         return status;
 211
 212 out_clnt_err:
 213         status = PTR_ERR(mnt_clnt);
 214         dprintk("NFS: failed to create MNT RPC client, status=%d\n", status);
 215         goto out;
 216
 217 out_call_err:
 218         dprintk("NFS: MNT request failed, status=%d\n", status);
 219         goto out;
 220
 221 out_mnt_err:
 222         dprintk("NFS: MNT server returned result %d\n", result.errno);
 223         status = result.errno;
 224         goto out;
 225 }
 226
 227 /**
 228  * nfs_umount - Notify a server that we have unmounted this export
 229  * @info: pointer to umount request arguments
 230  *
 231  * MOUNTPROC_UMNT is advisory, so we set a short timeout, and always
 232  * use UDP.
 233  */
 234 void nfs_umount(const struct nfs_mount_request *info)
 235 {
 236         static const struct rpc_timeout nfs_umnt_timeout = {
 237                 .to_initval = 1 * HZ,
 238                 .to_maxval = 3 * HZ,
 239                 .to_retries = 2,
 240         };
 241         struct rpc_create_args args = {
 242                 .net            = info->net,
 243                 .protocol       = IPPROTO_UDP,
 244                 .address        = info->sap,
 245                 .addrsize       = info->salen,
 246                 .timeout        = &nfs_umnt_timeout,
 247                 .servername     = info->hostname,
 248                 .program        = &mnt_program,
 249                 .version        = info->version,
 250                 .authflavor     = RPC_AUTH_UNIX,
 251                 .flags          = RPC_CLNT_CREATE_NOPING,
 252                 .cred           = current_cred(),
 253         };
 254         struct rpc_message msg  = {
 255                 .rpc_argp       = info->dirpath,
 256         };
 257         struct rpc_clnt *clnt;
 258         int status;
 259
 260         if (strlen(info->dirpath) > MNTPATHLEN)
 261                 return;
 262
 263         if (info->noresvport)
 264                 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 265
 266         clnt = rpc_create(&args);
 267         if (IS_ERR(clnt))
 268                 goto out_clnt_err;
 269
 270         dprintk("NFS: sending UMNT request for %s:%s\n",
 271                 (info->hostname ? info->hostname : "server"), info->dirpath);
 272
 273         if (info->version == NFS_MNT3_VERSION)
 274                 msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC3_UMNT];
 275         else
 276                 msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC_UMNT];
 277
 278         status = rpc_call_sync(clnt, &msg, 0);
 279         rpc_shutdown_client(clnt);
 280
 281         if (unlikely(status < 0))
 282                 goto out_call_err;
 283
 284         return;
 285
 286 out_clnt_err:
 287         dprintk("NFS: failed to create UMNT RPC client, status=%ld\n",
 288                         PTR_ERR(clnt));
 289         return;
 290
 291 out_call_err:
 292         dprintk("NFS: UMNT request failed, status=%d\n", status);
 293 }
 294
 295 /*
 296  * XDR encode/decode functions for MOUNT
 297  */
 298
 299 static void encode_mntdirpath(struct xdr_stream *xdr, const char *pathname)
 300 {
 301         const u32 pathname_len = strlen(pathname);
 302         __be32 *p;
 303
 304         p = xdr_reserve_space(xdr, 4 + pathname_len);
 305         xdr_encode_opaque(p, pathname, pathname_len);
 306 }
 307
 308 static void mnt_xdr_enc_dirpath(struct rpc_rqst *req, struct xdr_stream *xdr,
 309                                 const void *dirpath)
 310 {
 311         encode_mntdirpath(xdr, dirpath);
 312 }
 313
 314 /*
 315  * RFC 1094: "A non-zero status indicates some sort of error.  In this
 316  * case, the status is a UNIX error number."  This can be problematic
 317  * if the server and client use different errno values for the same
 318  * error.
 319  *
 320  * However, the OpenGroup XNFS spec provides a simple mapping that is
 321  * independent of local errno values on the server and the client.
 322  */
 323 static int decode_status(struct xdr_stream *xdr, struct mountres *res)
 324 {
 325         unsigned int i;
 326         u32 status;
 327         __be32 *p;
 328
 329         p = xdr_inline_decode(xdr, 4);
 330         if (unlikely(p == NULL))
 331                 return -EIO;
 332         status = be32_to_cpup(p);
 333
 334         for (i = 0; i < ARRAY_SIZE(mnt_errtbl); i++) {
 335                 if (mnt_errtbl[i].status == status) {
 336                         res->errno = mnt_errtbl[i].errno;
 337                         return 0;
 338                 }
 339         }
 340
 341         dprintk("NFS: unrecognized MNT status code: %u\n", status);
 342         res->errno = -EACCES;
 343         return 0;
 344 }
 345
 346 static int decode_fhandle(struct xdr_stream *xdr, struct mountres *res)
 347 {
 348         struct nfs_fh *fh = res->fh;
 349         __be32 *p;
 350
 351         p = xdr_inline_decode(xdr, NFS2_FHSIZE);
 352         if (unlikely(p == NULL))
 353                 return -EIO;
 354
 355         fh->size = NFS2_FHSIZE;
 356         memcpy(fh->data, p, NFS2_FHSIZE);
 357         return 0;
 358 }
 359
 360 static int mnt_xdr_dec_mountres(struct rpc_rqst *req,
 361                                 struct xdr_stream *xdr,
 362                                 void *data)
 363 {
 364         struct mountres *res = data;
 365         int status;
 366
 367         status = decode_status(xdr, res);
 368         if (unlikely(status != 0 || res->errno != 0))
 369                 return status;
 370         return decode_fhandle(xdr, res);
 371 }
 372
 373 static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
 374 {
 375         unsigned int i;
 376         u32 status;
 377         __be32 *p;
 378
 379         p = xdr_inline_decode(xdr, 4);
 380         if (unlikely(p == NULL))
 381                 return -EIO;
 382         status = be32_to_cpup(p);
 383
 384         for (i = 0; i < ARRAY_SIZE(mnt3_errtbl); i++) {
 385                 if (mnt3_errtbl[i].status == status) {
 386                         res->errno = mnt3_errtbl[i].errno;
 387                         return 0;
 388                 }
 389         }
 390
 391         dprintk("NFS: unrecognized MNT3 status code: %u\n", status);
 392         res->errno = -EACCES;
 393         return 0;
 394 }
 395
 396 static int decode_fhandle3(struct xdr_stream *xdr, struct mountres *res)
 397 {
 398         struct nfs_fh *fh = res->fh;
 399         u32 size;
 400         __be32 *p;
 401
 402         p = xdr_inline_decode(xdr, 4);
 403         if (unlikely(p == NULL))
 404                 return -EIO;
 405
 406         size = be32_to_cpup(p);
 407         if (size > NFS3_FHSIZE || size == 0)
 408                 return -EIO;
 409
 410         p = xdr_inline_decode(xdr, size);
 411         if (unlikely(p == NULL))
 412                 return -EIO;
 413
 414         fh->size = size;
 415         memcpy(fh->data, p, size);
 416         return 0;
 417 }
 418
 419 static int decode_auth_flavors(struct xdr_stream *xdr, struct mountres *res)
 420 {
 421         rpc_authflavor_t *flavors = res->auth_flavors;
 422         unsigned int *count = res->auth_count;
 423         u32 entries, i;
 424         __be32 *p;
 425
 426         if (*count == 0)
 427                 return 0;
 428
 429         p = xdr_inline_decode(xdr, 4);
 430         if (unlikely(p == NULL))
 431                 return -EIO;
 432         entries = be32_to_cpup(p);
 433         dprintk("NFS: received %u auth flavors\n", entries);
 434         if (entries > NFS_MAX_SECFLAVORS)
 435                 entries = NFS_MAX_SECFLAVORS;
 436
 437         p = xdr_inline_decode(xdr, 4 * entries);
 438         if (unlikely(p == NULL))
 439                 return -EIO;
 440
 441         if (entries > *count)
 442                 entries = *count;
 443
 444         for (i = 0; i < entries; i++) {
 445                 flavors[i] = be32_to_cpup(p++);
 446                 dprintk("NFS:   auth flavor[%u]: %d\n", i, flavors[i]);
 447         }
 448         *count = i;
 449
 450         return 0;
 451 }
 452
 453 static int mnt_xdr_dec_mountres3(struct rpc_rqst *req,
 454                                  struct xdr_stream *xdr,
 455                                  void *data)
 456 {
 457         struct mountres *res = data;
 458         int status;
 459
 460         status = decode_fhs_status(xdr, res);
 461         if (unlikely(status != 0 || res->errno != 0))
 462                 return status;
 463         status = decode_fhandle3(xdr, res);
 464         if (unlikely(status != 0)) {
 465                 res->errno = -EBADHANDLE;
 466                 return 0;
 467         }
 468         return decode_auth_flavors(xdr, res);
 469 }
 470
 471 static const struct rpc_procinfo mnt_procedures[] = {
 472         [MOUNTPROC_MNT] = {
 473                 .p_proc         = MOUNTPROC_MNT,
 474                 .p_encode       = mnt_xdr_enc_dirpath,
 475                 .p_decode       = mnt_xdr_dec_mountres,
 476                 .p_arglen       = MNT_enc_dirpath_sz,
 477                 .p_replen       = MNT_dec_mountres_sz,
 478                 .p_statidx      = MOUNTPROC_MNT,
 479                 .p_name         = "MOUNT",
 480         },
 481         [MOUNTPROC_UMNT] = {
 482                 .p_proc         = MOUNTPROC_UMNT,
 483                 .p_encode       = mnt_xdr_enc_dirpath,
 484                 .p_arglen       = MNT_enc_dirpath_sz,
 485                 .p_statidx      = MOUNTPROC_UMNT,
 486                 .p_name         = "UMOUNT",
 487         },
 488 };
 489
 490 static const struct rpc_procinfo mnt3_procedures[] = {
 491         [MOUNTPROC3_MNT] = {
 492                 .p_proc         = MOUNTPROC3_MNT,
 493                 .p_encode       = mnt_xdr_enc_dirpath,
 494                 .p_decode       = mnt_xdr_dec_mountres3,
 495                 .p_arglen       = MNT_enc_dirpath_sz,
 496                 .p_replen       = MNT_dec_mountres3_sz,
 497                 .p_statidx      = MOUNTPROC3_MNT,
 498                 .p_name         = "MOUNT",
 499         },
 500         [MOUNTPROC3_UMNT] = {
 501                 .p_proc         = MOUNTPROC3_UMNT,
 502                 .p_encode       = mnt_xdr_enc_dirpath,
 503                 .p_arglen       = MNT_enc_dirpath_sz,
 504                 .p_statidx      = MOUNTPROC3_UMNT,
 505                 .p_name         = "UMOUNT",
 506         },
 507 };
 508
 509 static unsigned int mnt_counts[ARRAY_SIZE(mnt_procedures)];
 510 static const struct rpc_version mnt_version1 = {
 511         .number         = 1,
 512         .nrprocs        = ARRAY_SIZE(mnt_procedures),
 513         .procs          = mnt_procedures,
 514         .counts         = mnt_counts,
 515 };
 516
 517 static unsigned int mnt3_counts[ARRAY_SIZE(mnt3_procedures)];
 518 static const struct rpc_version mnt_version3 = {
 519         .number         = 3,
 520         .nrprocs        = ARRAY_SIZE(mnt3_procedures),
 521         .procs          = mnt3_procedures,
 522         .counts         = mnt3_counts,
 523 };
 524
 525 static const struct rpc_version *mnt_version[] = {
 526         NULL,
 527         &mnt_version1,
 528         NULL,
 529         &mnt_version3,
 530 };
 531
 532 static struct rpc_stat mnt_stats;
 533
 534 static const struct rpc_program mnt_program = {
 535         .name           = "mount",
 536         .number         = NFS_MNT_PROGRAM,
 537         .nrvers         = ARRAY_SIZE(mnt_version),
 538         .version        = mnt_version,
 539         .stats          = &mnt_stats,
 540 };