fs/nfs/idmap.c

   1 /*
   2  * fs/nfs/idmap.c
   3  *
   4  *  UID and GID to name mapping for clients.
   5  *
   6  *  Copyright (c) 2002 The Regents of the University of Michigan.
   7  *  All rights reserved.
   8  *
   9  *  Marius Aamodt Eriksen <marius@umich.edu>
  10  *
  11  *  Redistribution and use in source and binary forms, with or without
  12  *  modification, are permitted provided that the following conditions
  13  *  are met:
  14  *
  15  *  1. Redistributions of source code must retain the above copyright
  16  *     notice, this list of conditions and the following disclaimer.
  17  *  2. Redistributions in binary form must reproduce the above copyright
  18  *     notice, this list of conditions and the following disclaimer in the
  19  *     documentation and/or other materials provided with the distribution.
  20  *  3. Neither the name of the University nor the names of its
  21  *     contributors may be used to endorse or promote products derived
  22  *     from this software without specific prior written permission.
  23  *
  24  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  25  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  26  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  27  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  31  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  32  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  33  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  34  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35  */
  36 #include <linux/types.h>
  37 #include <linux/parser.h>
  38 #include <linux/fs.h>
  39 #include <linux/nfs_idmap.h>
  40 #include <net/net_namespace.h>
  41 #include <linux/sunrpc/rpc_pipe_fs.h>
  42 #include <linux/nfs_fs.h>
  43 #include <linux/nfs_fs_sb.h>
  44 #include <linux/key.h>
  45 #include <linux/keyctl.h>
  46 #include <linux/key-type.h>
  47 #include <keys/user-type.h>
  48 #include <linux/module.h>
  49
  50 #include "internal.h"
  51 #include "netns.h"
  52
  53 #define NFS_UINT_MAXLEN 11
  54
  55 static const struct cred *id_resolver_cache;
  56 static struct key_type key_type_id_resolver_legacy;
  57
  58 struct idmap {
  59         struct rpc_pipe         *idmap_pipe;
  60         struct key_construction *idmap_key_cons;
  61         struct mutex            idmap_mutex;
  62 };
  63
  64 struct idmap_legacy_upcalldata {
  65         struct rpc_pipe_msg pipe_msg;
  66         struct idmap_msg idmap_msg;
  67         struct idmap *idmap;
  68 };
  69
  70 /**
  71  * nfs_fattr_init_names - initialise the nfs_fattr owner_name/group_name fields
  72  * @fattr: fully initialised struct nfs_fattr
  73  * @owner_name: owner name string cache
  74  * @group_name: group name string cache
  75  */
  76 void nfs_fattr_init_names(struct nfs_fattr *fattr,
  77                 struct nfs4_string *owner_name,
  78                 struct nfs4_string *group_name)
  79 {
  80         fattr->owner_name = owner_name;
  81         fattr->group_name = group_name;
  82 }
  83
  84 static void nfs_fattr_free_owner_name(struct nfs_fattr *fattr)
  85 {
  86         fattr->valid &= ~NFS_ATTR_FATTR_OWNER_NAME;
  87         kfree(fattr->owner_name->data);
  88 }
  89
  90 static void nfs_fattr_free_group_name(struct nfs_fattr *fattr)
  91 {
  92         fattr->valid &= ~NFS_ATTR_FATTR_GROUP_NAME;
  93         kfree(fattr->group_name->data);
  94 }
  95
  96 static bool nfs_fattr_map_owner_name(struct nfs_server *server, struct nfs_fattr *fattr)
  97 {
  98         struct nfs4_string *owner = fattr->owner_name;
  99         __u32 uid;
 100
 101         if (!(fattr->valid & NFS_ATTR_FATTR_OWNER_NAME))
 102                 return false;
 103         if (nfs_map_name_to_uid(server, owner->data, owner->len, &uid) == 0) {
 104                 fattr->uid = uid;
 105                 fattr->valid |= NFS_ATTR_FATTR_OWNER;
 106         }
 107         return true;
 108 }
 109
 110 static bool nfs_fattr_map_group_name(struct nfs_server *server, struct nfs_fattr *fattr)
 111 {
 112         struct nfs4_string *group = fattr->group_name;
 113         __u32 gid;
 114
 115         if (!(fattr->valid & NFS_ATTR_FATTR_GROUP_NAME))
 116                 return false;
 117         if (nfs_map_group_to_gid(server, group->data, group->len, &gid) == 0) {
 118                 fattr->gid = gid;
 119                 fattr->valid |= NFS_ATTR_FATTR_GROUP;
 120         }
 121         return true;
 122 }
 123
 124 /**
 125  * nfs_fattr_free_names - free up the NFSv4 owner and group strings
 126  * @fattr: a fully initialised nfs_fattr structure
 127  */
 128 void nfs_fattr_free_names(struct nfs_fattr *fattr)
 129 {
 130         if (fattr->valid & NFS_ATTR_FATTR_OWNER_NAME)
 131                 nfs_fattr_free_owner_name(fattr);
 132         if (fattr->valid & NFS_ATTR_FATTR_GROUP_NAME)
 133                 nfs_fattr_free_group_name(fattr);
 134 }
 135
 136 /**
 137  * nfs_fattr_map_and_free_names - map owner/group strings into uid/gid and free
 138  * @server: pointer to the filesystem nfs_server structure
 139  * @fattr: a fully initialised nfs_fattr structure
 140  *
 141  * This helper maps the cached NFSv4 owner/group strings in fattr into
 142  * their numeric uid/gid equivalents, and then frees the cached strings.
 143  */
 144 void nfs_fattr_map_and_free_names(struct nfs_server *server, struct nfs_fattr *fattr)
 145 {
 146         if (nfs_fattr_map_owner_name(server, fattr))
 147                 nfs_fattr_free_owner_name(fattr);
 148         if (nfs_fattr_map_group_name(server, fattr))
 149                 nfs_fattr_free_group_name(fattr);
 150 }
 151
 152 static int nfs_map_string_to_numeric(const char *name, size_t namelen, __u32 *res)
 153 {
 154         unsigned long val;
 155         char buf[16];
 156
 157         if (memchr(name, '@', namelen) != NULL || namelen >= sizeof(buf))
 158                 return 0;
 159         memcpy(buf, name, namelen);
 160         buf[namelen] = '\0';
 161         if (strict_strtoul(buf, 0, &val) != 0)
 162                 return 0;
 163         *res = val;
 164         return 1;
 165 }
 166
 167 static int nfs_map_numeric_to_string(__u32 id, char *buf, size_t buflen)
 168 {
 169         return snprintf(buf, buflen, "%u", id);
 170 }
 171
 172 static struct key_type key_type_id_resolver = {
 173         .name           = "id_resolver",
 174         .instantiate    = user_instantiate,
 175         .match          = user_match,
 176         .revoke         = user_revoke,
 177         .destroy        = user_destroy,
 178         .describe       = user_describe,
 179         .read           = user_read,
 180 };
 181
 182 static int nfs_idmap_init_keyring(void)
 183 {
 184         struct cred *cred;
 185         struct key *keyring;
 186         int ret = 0;
 187
 188         printk(KERN_NOTICE "NFS: Registering the %s key type\n",
 189                 key_type_id_resolver.name);
 190
 191         cred = prepare_kernel_cred(NULL);
 192         if (!cred)
 193                 return -ENOMEM;
 194
 195         keyring = key_alloc(&key_type_keyring, ".id_resolver", 0, 0, cred,
 196                              (KEY_POS_ALL & ~KEY_POS_SETATTR) |
 197                              KEY_USR_VIEW | KEY_USR_READ,
 198                              KEY_ALLOC_NOT_IN_QUOTA);
 199         if (IS_ERR(keyring)) {
 200                 ret = PTR_ERR(keyring);
 201                 goto failed_put_cred;
 202         }
 203
 204         ret = key_instantiate_and_link(keyring, NULL, 0, NULL, NULL);
 205         if (ret < 0)
 206                 goto failed_put_key;
 207
 208         ret = register_key_type(&key_type_id_resolver);
 209         if (ret < 0)
 210                 goto failed_put_key;
 211
 212         ret = register_key_type(&key_type_id_resolver_legacy);
 213         if (ret < 0)
 214                 goto failed_reg_legacy;
 215
 216         set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
 217         cred->thread_keyring = keyring;
 218         cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
 219         id_resolver_cache = cred;
 220         return 0;
 221
 222 failed_reg_legacy:
 223         unregister_key_type(&key_type_id_resolver);
 224 failed_put_key:
 225         key_put(keyring);
 226 failed_put_cred:
 227         put_cred(cred);
 228         return ret;
 229 }
 230
 231 static void nfs_idmap_quit_keyring(void)
 232 {
 233         key_revoke(id_resolver_cache->thread_keyring);
 234         unregister_key_type(&key_type_id_resolver);
 235         unregister_key_type(&key_type_id_resolver_legacy);
 236         put_cred(id_resolver_cache);
 237 }
 238
 239 /*
 240  * Assemble the description to pass to request_key()
 241  * This function will allocate a new string and update dest to point
 242  * at it.  The caller is responsible for freeing dest.
 243  *
 244  * On error 0 is returned.  Otherwise, the length of dest is returned.
 245  */
 246 static ssize_t nfs_idmap_get_desc(const char *name, size_t namelen,
 247                                 const char *type, size_t typelen, char **desc)
 248 {
 249         char *cp;
 250         size_t desclen = typelen + namelen + 2;
 251
 252         *desc = kmalloc(desclen, GFP_KERNEL);
 253         if (!*desc)
 254                 return -ENOMEM;
 255
 256         cp = *desc;
 257         memcpy(cp, type, typelen);
 258         cp += typelen;
 259         *cp++ = ':';
 260
 261         memcpy(cp, name, namelen);
 262         cp += namelen;
 263         *cp = '\0';
 264         return desclen;
 265 }
 266
 267 static ssize_t nfs_idmap_request_key(struct key_type *key_type,
 268                                      const char *name, size_t namelen,
 269                                      const char *type, void *data,
 270                                      size_t data_size, struct idmap *idmap)
 271 {
 272         const struct cred *saved_cred;
 273         struct key *rkey;
 274         char *desc;
 275         struct user_key_payload *payload;
 276         ssize_t ret;
 277
 278         ret = nfs_idmap_get_desc(name, namelen, type, strlen(type), &desc);
 279         if (ret <= 0)
 280                 goto out;
 281
 282         saved_cred = override_creds(id_resolver_cache);
 283         if (idmap)
 284                 rkey = request_key_with_auxdata(key_type, desc, "", 0, idmap);
 285         else
 286                 rkey = request_key(&key_type_id_resolver, desc, "");
 287         revert_creds(saved_cred);
 288
 289         kfree(desc);
 290         if (IS_ERR(rkey)) {
 291                 ret = PTR_ERR(rkey);
 292                 goto out;
 293         }
 294
 295         rcu_read_lock();
 296         rkey->perm |= KEY_USR_VIEW;
 297
 298         ret = key_validate(rkey);
 299         if (ret < 0)
 300                 goto out_up;
 301
 302         payload = rcu_dereference(rkey->payload.data);
 303         if (IS_ERR_OR_NULL(payload)) {
 304                 ret = PTR_ERR(payload);
 305                 goto out_up;
 306         }
 307
 308         ret = payload->datalen;
 309         if (ret > 0 && ret <= data_size)
 310                 memcpy(data, payload->data, ret);
 311         else
 312                 ret = -EINVAL;
 313
 314 out_up:
 315         rcu_read_unlock();
 316         key_put(rkey);
 317 out:
 318         return ret;
 319 }
 320
 321 static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
 322                                  const char *type, void *data,
 323                                  size_t data_size, struct idmap *idmap)
 324 {
 325         ssize_t ret = nfs_idmap_request_key(&key_type_id_resolver,
 326                                             name, namelen, type, data,
 327                                             data_size, NULL);
 328         if (ret < 0) {
 329                 mutex_lock(&idmap->idmap_mutex);
 330                 ret = nfs_idmap_request_key(&key_type_id_resolver_legacy,
 331                                             name, namelen, type, data,
 332                                             data_size, idmap);
 333                 idmap->idmap_key_cons = NULL;
 334                 mutex_unlock(&idmap->idmap_mutex);
 335         }
 336         return ret;
 337 }
 338
 339 /* ID -> Name */
 340 static ssize_t nfs_idmap_lookup_name(__u32 id, const char *type, char *buf,
 341                                      size_t buflen, struct idmap *idmap)
 342 {
 343         char id_str[NFS_UINT_MAXLEN];
 344         int id_len;
 345         ssize_t ret;
 346
 347         id_len = snprintf(id_str, sizeof(id_str), "%u", id);
 348         ret = nfs_idmap_get_key(id_str, id_len, type, buf, buflen, idmap);
 349         if (ret < 0)
 350                 return -EINVAL;
 351         return ret;
 352 }
 353
 354 /* Name -> ID */
 355 static int nfs_idmap_lookup_id(const char *name, size_t namelen, const char *type,
 356                                __u32 *id, struct idmap *idmap)
 357 {
 358         char id_str[NFS_UINT_MAXLEN];
 359         long id_long;
 360         ssize_t data_size;
 361         int ret = 0;
 362
 363         data_size = nfs_idmap_get_key(name, namelen, type, id_str, NFS_UINT_MAXLEN, idmap);
 364         if (data_size <= 0) {
 365                 ret = -EINVAL;
 366         } else {
 367                 ret = strict_strtol(id_str, 10, &id_long);
 368                 *id = (__u32)id_long;
 369         }
 370         return ret;
 371 }
 372
 373 /* idmap classic begins here */
 374
 375 enum {
 376         Opt_find_uid, Opt_find_gid, Opt_find_user, Opt_find_group, Opt_find_err
 377 };
 378
 379 static const match_table_t nfs_idmap_tokens = {
 380         { Opt_find_uid, "uid:%s" },
 381         { Opt_find_gid, "gid:%s" },
 382         { Opt_find_user, "user:%s" },
 383         { Opt_find_group, "group:%s" },
 384         { Opt_find_err, NULL }
 385 };
 386
 387 static int nfs_idmap_legacy_upcall(struct key_construction *, const char *, void *);
 388 static ssize_t idmap_pipe_downcall(struct file *, const char __user *,
 389                                    size_t);
 390 static void idmap_release_pipe(struct inode *);
 391 static void idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
 392
 393 static const struct rpc_pipe_ops idmap_upcall_ops = {
 394         .upcall         = rpc_pipe_generic_upcall,
 395         .downcall       = idmap_pipe_downcall,
 396         .release_pipe   = idmap_release_pipe,
 397         .destroy_msg    = idmap_pipe_destroy_msg,
 398 };
 399
 400 static struct key_type key_type_id_resolver_legacy = {
 401         .name           = "id_legacy",
 402         .instantiate    = user_instantiate,
 403         .match          = user_match,
 404         .revoke         = user_revoke,
 405         .destroy        = user_destroy,
 406         .describe       = user_describe,
 407         .read           = user_read,
 408         .request_key    = nfs_idmap_legacy_upcall,
 409 };
 410
 411 static void __nfs_idmap_unregister(struct rpc_pipe *pipe)
 412 {
 413         if (pipe->dentry)
 414                 rpc_unlink(pipe->dentry);
 415 }
 416
 417 static int __nfs_idmap_register(struct dentry *dir,
 418                                      struct idmap *idmap,
 419                                      struct rpc_pipe *pipe)
 420 {
 421         struct dentry *dentry;
 422
 423         dentry = rpc_mkpipe_dentry(dir, "idmap", idmap, pipe);
 424         if (IS_ERR(dentry))
 425                 return PTR_ERR(dentry);
 426         pipe->dentry = dentry;
 427         return 0;
 428 }
 429
 430 static void nfs_idmap_unregister(struct nfs_client *clp,
 431                                       struct rpc_pipe *pipe)
 432 {
 433         struct net *net = clp->cl_net;
 434         struct super_block *pipefs_sb;
 435
 436         pipefs_sb = rpc_get_sb_net(net);
 437         if (pipefs_sb) {
 438                 __nfs_idmap_unregister(pipe);
 439                 rpc_put_sb_net(net);
 440         }
 441 }
 442
 443 static int nfs_idmap_register(struct nfs_client *clp,
 444                                    struct idmap *idmap,
 445                                    struct rpc_pipe *pipe)
 446 {
 447         struct net *net = clp->cl_net;
 448         struct super_block *pipefs_sb;
 449         int err = 0;
 450
 451         pipefs_sb = rpc_get_sb_net(net);
 452         if (pipefs_sb) {
 453                 if (clp->cl_rpcclient->cl_dentry)
 454                         err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
 455                                                    idmap, pipe);
 456                 rpc_put_sb_net(net);
 457         }
 458         return err;
 459 }
 460
 461 int
 462 nfs_idmap_new(struct nfs_client *clp)
 463 {
 464         struct idmap *idmap;
 465         struct rpc_pipe *pipe;
 466         int error;
 467
 468         BUG_ON(clp->cl_idmap != NULL);
 469
 470         idmap = kzalloc(sizeof(*idmap), GFP_KERNEL);
 471         if (idmap == NULL)
 472                 return -ENOMEM;
 473
 474         pipe = rpc_mkpipe_data(&idmap_upcall_ops, 0);
 475         if (IS_ERR(pipe)) {
 476                 error = PTR_ERR(pipe);
 477                 kfree(idmap);
 478                 return error;
 479         }
 480         error = nfs_idmap_register(clp, idmap, pipe);
 481         if (error) {
 482                 rpc_destroy_pipe_data(pipe);
 483                 kfree(idmap);
 484                 return error;
 485         }
 486         idmap->idmap_pipe = pipe;
 487         mutex_init(&idmap->idmap_mutex);
 488
 489         clp->cl_idmap = idmap;
 490         return 0;
 491 }
 492
 493 void
 494 nfs_idmap_delete(struct nfs_client *clp)
 495 {
 496         struct idmap *idmap = clp->cl_idmap;
 497
 498         if (!idmap)
 499                 return;
 500         nfs_idmap_unregister(clp, idmap->idmap_pipe);
 501         rpc_destroy_pipe_data(idmap->idmap_pipe);
 502         clp->cl_idmap = NULL;
 503         kfree(idmap);
 504 }
 505
 506 static int __rpc_pipefs_event(struct nfs_client *clp, unsigned long event,
 507                               struct super_block *sb)
 508 {
 509         int err = 0;
 510
 511         switch (event) {
 512         case RPC_PIPEFS_MOUNT:
 513                 BUG_ON(clp->cl_rpcclient->cl_dentry == NULL);
 514                 err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
 515                                                 clp->cl_idmap,
 516                                                 clp->cl_idmap->idmap_pipe);
 517                 break;
 518         case RPC_PIPEFS_UMOUNT:
 519                 if (clp->cl_idmap->idmap_pipe) {
 520                         struct dentry *parent;
 521
 522                         parent = clp->cl_idmap->idmap_pipe->dentry->d_parent;
 523                         __nfs_idmap_unregister(clp->cl_idmap->idmap_pipe);
 524                         /*
 525                          * Note: This is a dirty hack. SUNRPC hook has been
 526                          * called already but simple_rmdir() call for the
 527                          * directory returned with error because of idmap pipe
 528                          * inside. Thus now we have to remove this directory
 529                          * here.
 530                          */
 531                         if (rpc_rmdir(parent))
 532                                 printk(KERN_ERR "NFS: %s: failed to remove "
 533                                         "clnt dir!\n", __func__);
 534                 }
 535                 break;
 536         default:
 537                 printk(KERN_ERR "NFS: %s: unknown event: %ld\n", __func__,
 538                         event);
 539                 return -ENOTSUPP;
 540         }
 541         return err;
 542 }
 543
 544 static struct nfs_client *nfs_get_client_for_event(struct net *net, int event)
 545 {
 546         struct nfs_net *nn = net_generic(net, nfs_net_id);
 547         struct dentry *cl_dentry;
 548         struct nfs_client *clp;
 549         int err;
 550
 551 restart:
 552         spin_lock(&nn->nfs_client_lock);
 553         list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
 554                 /* Wait for initialisation to finish */
 555                 if (clp->cl_cons_state == NFS_CS_INITING) {
 556                         atomic_inc(&clp->cl_count);
 557                         spin_unlock(&nn->nfs_client_lock);
 558                         err = nfs_wait_client_init_complete(clp);
 559                         nfs_put_client(clp);
 560                         if (err)
 561                                 return NULL;
 562                         goto restart;
 563                 }
 564                 /* Skip nfs_clients that failed to initialise */
 565                 if (clp->cl_cons_state < 0)
 566                         continue;
 567                 smp_rmb();
 568                 if (clp->rpc_ops != &nfs_v4_clientops)
 569                         continue;
 570                 cl_dentry = clp->cl_idmap->idmap_pipe->dentry;
 571                 if (((event == RPC_PIPEFS_MOUNT) && cl_dentry) ||
 572                     ((event == RPC_PIPEFS_UMOUNT) && !cl_dentry))
 573                         continue;
 574                 atomic_inc(&clp->cl_count);
 575                 spin_unlock(&nn->nfs_client_lock);
 576                 return clp;
 577         }
 578         spin_unlock(&nn->nfs_client_lock);
 579         return NULL;
 580 }
 581
 582 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
 583                             void *ptr)
 584 {
 585         struct super_block *sb = ptr;
 586         struct nfs_client *clp;
 587         int error = 0;
 588
 589         if (!try_module_get(THIS_MODULE))
 590                 return 0;
 591
 592         while ((clp = nfs_get_client_for_event(sb->s_fs_info, event))) {
 593                 error = __rpc_pipefs_event(clp, event, sb);
 594                 nfs_put_client(clp);
 595                 if (error)
 596                         break;
 597         }
 598         module_put(THIS_MODULE);
 599         return error;
 600 }
 601
 602 #define PIPEFS_NFS_PRIO         1
 603
 604 static struct notifier_block nfs_idmap_block = {
 605         .notifier_call  = rpc_pipefs_event,
 606         .priority       = SUNRPC_PIPEFS_NFS_PRIO,
 607 };
 608
 609 int nfs_idmap_init(void)
 610 {
 611         int ret;
 612         ret = nfs_idmap_init_keyring();
 613         if (ret != 0)
 614                 goto out;
 615         ret = rpc_pipefs_notifier_register(&nfs_idmap_block);
 616         if (ret != 0)
 617                 nfs_idmap_quit_keyring();
 618 out:
 619         return ret;
 620 }
 621
 622 void nfs_idmap_quit(void)
 623 {
 624         rpc_pipefs_notifier_unregister(&nfs_idmap_block);
 625         nfs_idmap_quit_keyring();
 626 }
 627
 628 static int nfs_idmap_prepare_message(char *desc, struct idmap *idmap,
 629                                      struct idmap_msg *im,
 630                                      struct rpc_pipe_msg *msg)
 631 {
 632         substring_t substr;
 633         int token, ret;
 634
 635         memset(im,  0, sizeof(*im));
 636         memset(msg, 0, sizeof(*msg));
 637
 638         im->im_type = IDMAP_TYPE_GROUP;
 639         token = match_token(desc, nfs_idmap_tokens, &substr);
 640
 641         switch (token) {
 642         case Opt_find_uid:
 643                 im->im_type = IDMAP_TYPE_USER;
 644         case Opt_find_gid:
 645                 im->im_conv = IDMAP_CONV_NAMETOID;
 646                 ret = match_strlcpy(im->im_name, &substr, IDMAP_NAMESZ);
 647                 break;
 648
 649         case Opt_find_user:
 650                 im->im_type = IDMAP_TYPE_USER;
 651         case Opt_find_group:
 652                 im->im_conv = IDMAP_CONV_IDTONAME;
 653                 ret = match_int(&substr, &im->im_id);
 654                 break;
 655
 656         default:
 657                 ret = -EINVAL;
 658                 goto out;
 659         }
 660
 661         msg->data = im;
 662         msg->len  = sizeof(struct idmap_msg);
 663
 664 out:
 665         return ret;
 666 }
 667
 668 static int nfs_idmap_legacy_upcall(struct key_construction *cons,
 669                                    const char *op,
 670                                    void *aux)
 671 {
 672         struct idmap_legacy_upcalldata *data;
 673         struct rpc_pipe_msg *msg;
 674         struct idmap_msg *im;
 675         struct idmap *idmap = (struct idmap *)aux;
 676         struct key *key = cons->key;
 677         int ret = -ENOMEM;
 678
 679         /* msg and im are freed in idmap_pipe_destroy_msg */
 680         data = kmalloc(sizeof(*data), GFP_KERNEL);
 681         if (!data)
 682                 goto out1;
 683
 684         msg = &data->pipe_msg;
 685         im = &data->idmap_msg;
 686         data->idmap = idmap;
 687
 688         ret = nfs_idmap_prepare_message(key->description, idmap, im, msg);
 689         if (ret < 0)
 690                 goto out2;
 691
 692         BUG_ON(idmap->idmap_key_cons != NULL);
 693         idmap->idmap_key_cons = cons;
 694
 695         ret = rpc_queue_upcall(idmap->idmap_pipe, msg);
 696         if (ret < 0)
 697                 goto out3;
 698
 699         return ret;
 700
 701 out3:
 702         idmap->idmap_key_cons = NULL;
 703 out2:
 704         kfree(data);
 705 out1:
 706         complete_request_key(cons, ret);
 707         return ret;
 708 }
 709
 710 static int nfs_idmap_instantiate(struct key *key, struct key *authkey, char *data)
 711 {
 712         return key_instantiate_and_link(key, data, strlen(data) + 1,
 713                                         id_resolver_cache->thread_keyring,
 714                                         authkey);
 715 }
 716
 717 static int nfs_idmap_read_message(struct idmap_msg *im, struct key *key, struct key *authkey)
 718 {
 719         char id_str[NFS_UINT_MAXLEN];
 720         int ret = -EINVAL;
 721
 722         switch (im->im_conv) {
 723         case IDMAP_CONV_NAMETOID:
 724                 sprintf(id_str, "%d", im->im_id);
 725                 ret = nfs_idmap_instantiate(key, authkey, id_str);
 726                 break;
 727         case IDMAP_CONV_IDTONAME:
 728                 ret = nfs_idmap_instantiate(key, authkey, im->im_name);
 729                 break;
 730         }
 731
 732         return ret;
 733 }
 734
 735 static ssize_t
 736 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 737 {
 738         struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
 739         struct idmap *idmap = (struct idmap *)rpci->private;
 740         struct key_construction *cons;
 741         struct idmap_msg im;
 742         size_t namelen_in;
 743         int ret;
 744
 745         /* If instantiation is successful, anyone waiting for key construction
 746          * will have been woken up and someone else may now have used
 747          * idmap_key_cons - so after this point we may no longer touch it.
 748          */
 749         cons = ACCESS_ONCE(idmap->idmap_key_cons);
 750         idmap->idmap_key_cons = NULL;
 751
 752         if (mlen != sizeof(im)) {
 753                 ret = -ENOSPC;
 754                 goto out;
 755         }
 756
 757         if (copy_from_user(&im, src, mlen) != 0) {
 758                 ret = -EFAULT;
 759                 goto out;
 760         }
 761
 762         if (!(im.im_status & IDMAP_STATUS_SUCCESS)) {
 763                 ret = -ENOKEY;
 764                 goto out;
 765         }
 766
 767         namelen_in = strnlen(im.im_name, IDMAP_NAMESZ);
 768         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ) {
 769                 ret = -EINVAL;
 770                 goto out;
 771         }
 772
 773         ret = nfs_idmap_read_message(&im, cons->key, cons->authkey);
 774         if (ret >= 0) {
 775                 key_set_timeout(cons->key, nfs_idmap_cache_timeout);
 776                 ret = mlen;
 777         }
 778
 779 out:
 780         complete_request_key(cons, ret);
 781         return ret;
 782 }
 783
 784 static void
 785 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 786 {
 787         struct idmap_legacy_upcalldata *data = container_of(msg,
 788                         struct idmap_legacy_upcalldata,
 789                         pipe_msg);
 790         struct idmap *idmap = data->idmap;
 791         struct key_construction *cons;
 792         if (msg->errno) {
 793                 cons = ACCESS_ONCE(idmap->idmap_key_cons);
 794                 idmap->idmap_key_cons = NULL;
 795                 complete_request_key(cons, msg->errno);
 796         }
 797         /* Free memory allocated in nfs_idmap_legacy_upcall() */
 798         kfree(data);
 799 }
 800
 801 static void
 802 idmap_release_pipe(struct inode *inode)
 803 {
 804         struct rpc_inode *rpci = RPC_I(inode);
 805         struct idmap *idmap = (struct idmap *)rpci->private;
 806         idmap->idmap_key_cons = NULL;
 807 }
 808
 809 int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, __u32 *uid)
 810 {
 811         struct idmap *idmap = server->nfs_client->cl_idmap;
 812
 813         if (nfs_map_string_to_numeric(name, namelen, uid))
 814                 return 0;
 815         return nfs_idmap_lookup_id(name, namelen, "uid", uid, idmap);
 816 }
 817
 818 int nfs_map_group_to_gid(const struct nfs_server *server, const char *name, size_t namelen, __u32 *gid)
 819 {
 820         struct idmap *idmap = server->nfs_client->cl_idmap;
 821
 822         if (nfs_map_string_to_numeric(name, namelen, gid))
 823                 return 0;
 824         return nfs_idmap_lookup_id(name, namelen, "gid", gid, idmap);
 825 }
 826
 827 int nfs_map_uid_to_name(const struct nfs_server *server, __u32 uid, char *buf, size_t buflen)
 828 {
 829         struct idmap *idmap = server->nfs_client->cl_idmap;
 830         int ret = -EINVAL;
 831
 832         if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
 833                 ret = nfs_idmap_lookup_name(uid, "user", buf, buflen, idmap);
 834         if (ret < 0)
 835                 ret = nfs_map_numeric_to_string(uid, buf, buflen);
 836         return ret;
 837 }
 838 int nfs_map_gid_to_group(const struct nfs_server *server, __u32 gid, char *buf, size_t buflen)
 839 {
 840         struct idmap *idmap = server->nfs_client->cl_idmap;
 841         int ret = -EINVAL;
 842
 843         if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
 844                 ret = nfs_idmap_lookup_name(gid, "group", buf, buflen, idmap);
 845         if (ret < 0)
 846                 ret = nfs_map_numeric_to_string(gid, buf, buflen);
 847         return ret;
 848 }