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 /**
  65  * nfs_fattr_init_names - initialise the nfs_fattr owner_name/group_name fields
  66  * @fattr: fully initialised struct nfs_fattr
  67  * @owner_name: owner name string cache
  68  * @group_name: group name string cache
  69  */
  70 void nfs_fattr_init_names(struct nfs_fattr *fattr,
  71                 struct nfs4_string *owner_name,
  72                 struct nfs4_string *group_name)
  73 {
  74         fattr->owner_name = owner_name;
  75         fattr->group_name = group_name;
  76 }
  77
  78 static void nfs_fattr_free_owner_name(struct nfs_fattr *fattr)
  79 {
  80         fattr->valid &= ~NFS_ATTR_FATTR_OWNER_NAME;
  81         kfree(fattr->owner_name->data);
  82 }
  83
  84 static void nfs_fattr_free_group_name(struct nfs_fattr *fattr)
  85 {
  86         fattr->valid &= ~NFS_ATTR_FATTR_GROUP_NAME;
  87         kfree(fattr->group_name->data);
  88 }
  89
  90 static bool nfs_fattr_map_owner_name(struct nfs_server *server, struct nfs_fattr *fattr)
  91 {
  92         struct nfs4_string *owner = fattr->owner_name;
  93         __u32 uid;
  94
  95         if (!(fattr->valid & NFS_ATTR_FATTR_OWNER_NAME))
  96                 return false;
  97         if (nfs_map_name_to_uid(server, owner->data, owner->len, &uid) == 0) {
  98                 fattr->uid = uid;
  99                 fattr->valid |= NFS_ATTR_FATTR_OWNER;
 100         }
 101         return true;
 102 }
 103
 104 static bool nfs_fattr_map_group_name(struct nfs_server *server, struct nfs_fattr *fattr)
 105 {
 106         struct nfs4_string *group = fattr->group_name;
 107         __u32 gid;
 108
 109         if (!(fattr->valid & NFS_ATTR_FATTR_GROUP_NAME))
 110                 return false;
 111         if (nfs_map_group_to_gid(server, group->data, group->len, &gid) == 0) {
 112                 fattr->gid = gid;
 113                 fattr->valid |= NFS_ATTR_FATTR_GROUP;
 114         }
 115         return true;
 116 }
 117
 118 /**
 119  * nfs_fattr_free_names - free up the NFSv4 owner and group strings
 120  * @fattr: a fully initialised nfs_fattr structure
 121  */
 122 void nfs_fattr_free_names(struct nfs_fattr *fattr)
 123 {
 124         if (fattr->valid & NFS_ATTR_FATTR_OWNER_NAME)
 125                 nfs_fattr_free_owner_name(fattr);
 126         if (fattr->valid & NFS_ATTR_FATTR_GROUP_NAME)
 127                 nfs_fattr_free_group_name(fattr);
 128 }
 129
 130 /**
 131  * nfs_fattr_map_and_free_names - map owner/group strings into uid/gid and free
 132  * @server: pointer to the filesystem nfs_server structure
 133  * @fattr: a fully initialised nfs_fattr structure
 134  *
 135  * This helper maps the cached NFSv4 owner/group strings in fattr into
 136  * their numeric uid/gid equivalents, and then frees the cached strings.
 137  */
 138 void nfs_fattr_map_and_free_names(struct nfs_server *server, struct nfs_fattr *fattr)
 139 {
 140         if (nfs_fattr_map_owner_name(server, fattr))
 141                 nfs_fattr_free_owner_name(fattr);
 142         if (nfs_fattr_map_group_name(server, fattr))
 143                 nfs_fattr_free_group_name(fattr);
 144 }
 145
 146 static int nfs_map_string_to_numeric(const char *name, size_t namelen, __u32 *res)
 147 {
 148         unsigned long val;
 149         char buf[16];
 150
 151         if (memchr(name, '@', namelen) != NULL || namelen >= sizeof(buf))
 152                 return 0;
 153         memcpy(buf, name, namelen);
 154         buf[namelen] = '\0';
 155         if (strict_strtoul(buf, 0, &val) != 0)
 156                 return 0;
 157         *res = val;
 158         return 1;
 159 }
 160
 161 static int nfs_map_numeric_to_string(__u32 id, char *buf, size_t buflen)
 162 {
 163         return snprintf(buf, buflen, "%u", id);
 164 }
 165
 166 static struct key_type key_type_id_resolver = {
 167         .name           = "id_resolver",
 168         .instantiate    = user_instantiate,
 169         .match          = user_match,
 170         .revoke         = user_revoke,
 171         .destroy        = user_destroy,
 172         .describe       = user_describe,
 173         .read           = user_read,
 174 };
 175
 176 static int nfs_idmap_init_keyring(void)
 177 {
 178         struct cred *cred;
 179         struct key *keyring;
 180         int ret = 0;
 181
 182         printk(KERN_NOTICE "NFS: Registering the %s key type\n",
 183                 key_type_id_resolver.name);
 184
 185         cred = prepare_kernel_cred(NULL);
 186         if (!cred)
 187                 return -ENOMEM;
 188
 189         keyring = key_alloc(&key_type_keyring, ".id_resolver", 0, 0, cred,
 190                              (KEY_POS_ALL & ~KEY_POS_SETATTR) |
 191                              KEY_USR_VIEW | KEY_USR_READ,
 192                              KEY_ALLOC_NOT_IN_QUOTA);
 193         if (IS_ERR(keyring)) {
 194                 ret = PTR_ERR(keyring);
 195                 goto failed_put_cred;
 196         }
 197
 198         ret = key_instantiate_and_link(keyring, NULL, 0, NULL, NULL);
 199         if (ret < 0)
 200                 goto failed_put_key;
 201
 202         ret = register_key_type(&key_type_id_resolver);
 203         if (ret < 0)
 204                 goto failed_put_key;
 205
 206         ret = register_key_type(&key_type_id_resolver_legacy);
 207         if (ret < 0)
 208                 goto failed_reg_legacy;
 209
 210         set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
 211         cred->thread_keyring = keyring;
 212         cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
 213         id_resolver_cache = cred;
 214         return 0;
 215
 216 failed_reg_legacy:
 217         unregister_key_type(&key_type_id_resolver);
 218 failed_put_key:
 219         key_put(keyring);
 220 failed_put_cred:
 221         put_cred(cred);
 222         return ret;
 223 }
 224
 225 static void nfs_idmap_quit_keyring(void)
 226 {
 227         key_revoke(id_resolver_cache->thread_keyring);
 228         unregister_key_type(&key_type_id_resolver);
 229         unregister_key_type(&key_type_id_resolver_legacy);
 230         put_cred(id_resolver_cache);
 231 }
 232
 233 /*
 234  * Assemble the description to pass to request_key()
 235  * This function will allocate a new string and update dest to point
 236  * at it.  The caller is responsible for freeing dest.
 237  *
 238  * On error 0 is returned.  Otherwise, the length of dest is returned.
 239  */
 240 static ssize_t nfs_idmap_get_desc(const char *name, size_t namelen,
 241                                 const char *type, size_t typelen, char **desc)
 242 {
 243         char *cp;
 244         size_t desclen = typelen + namelen + 2;
 245
 246         *desc = kmalloc(desclen, GFP_KERNEL);
 247         if (!*desc)
 248                 return -ENOMEM;
 249
 250         cp = *desc;
 251         memcpy(cp, type, typelen);
 252         cp += typelen;
 253         *cp++ = ':';
 254
 255         memcpy(cp, name, namelen);
 256         cp += namelen;
 257         *cp = '\0';
 258         return desclen;
 259 }
 260
 261 static ssize_t nfs_idmap_request_key(struct key_type *key_type,
 262                                      const char *name, size_t namelen,
 263                                      const char *type, void *data,
 264                                      size_t data_size, struct idmap *idmap)
 265 {
 266         const struct cred *saved_cred;
 267         struct key *rkey;
 268         char *desc;
 269         struct user_key_payload *payload;
 270         ssize_t ret;
 271
 272         ret = nfs_idmap_get_desc(name, namelen, type, strlen(type), &desc);
 273         if (ret <= 0)
 274                 goto out;
 275
 276         saved_cred = override_creds(id_resolver_cache);
 277         if (idmap)
 278                 rkey = request_key_with_auxdata(key_type, desc, "", 0, idmap);
 279         else
 280                 rkey = request_key(&key_type_id_resolver, desc, "");
 281         revert_creds(saved_cred);
 282
 283         kfree(desc);
 284         if (IS_ERR(rkey)) {
 285                 ret = PTR_ERR(rkey);
 286                 goto out;
 287         }
 288
 289         rcu_read_lock();
 290         rkey->perm |= KEY_USR_VIEW;
 291
 292         ret = key_validate(rkey);
 293         if (ret < 0)
 294                 goto out_up;
 295
 296         payload = rcu_dereference(rkey->payload.data);
 297         if (IS_ERR_OR_NULL(payload)) {
 298                 ret = PTR_ERR(payload);
 299                 goto out_up;
 300         }
 301
 302         ret = payload->datalen;
 303         if (ret > 0 && ret <= data_size)
 304                 memcpy(data, payload->data, ret);
 305         else
 306                 ret = -EINVAL;
 307
 308 out_up:
 309         rcu_read_unlock();
 310         key_put(rkey);
 311 out:
 312         return ret;
 313 }
 314
 315 static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
 316                                  const char *type, void *data,
 317                                  size_t data_size, struct idmap *idmap)
 318 {
 319         ssize_t ret = nfs_idmap_request_key(&key_type_id_resolver,
 320                                             name, namelen, type, data,
 321                                             data_size, NULL);
 322         if (ret < 0) {
 323                 mutex_lock(&idmap->idmap_mutex);
 324                 ret = nfs_idmap_request_key(&key_type_id_resolver_legacy,
 325                                             name, namelen, type, data,
 326                                             data_size, idmap);
 327                 mutex_unlock(&idmap->idmap_mutex);
 328         }
 329         return ret;
 330 }
 331
 332 /* ID -> Name */
 333 static ssize_t nfs_idmap_lookup_name(__u32 id, const char *type, char *buf,
 334                                      size_t buflen, struct idmap *idmap)
 335 {
 336         char id_str[NFS_UINT_MAXLEN];
 337         int id_len;
 338         ssize_t ret;
 339
 340         id_len = snprintf(id_str, sizeof(id_str), "%u", id);
 341         ret = nfs_idmap_get_key(id_str, id_len, type, buf, buflen, idmap);
 342         if (ret < 0)
 343                 return -EINVAL;
 344         return ret;
 345 }
 346
 347 /* Name -> ID */
 348 static int nfs_idmap_lookup_id(const char *name, size_t namelen, const char *type,
 349                                __u32 *id, struct idmap *idmap)
 350 {
 351         char id_str[NFS_UINT_MAXLEN];
 352         long id_long;
 353         ssize_t data_size;
 354         int ret = 0;
 355
 356         data_size = nfs_idmap_get_key(name, namelen, type, id_str, NFS_UINT_MAXLEN, idmap);
 357         if (data_size <= 0) {
 358                 ret = -EINVAL;
 359         } else {
 360                 ret = strict_strtol(id_str, 10, &id_long);
 361                 *id = (__u32)id_long;
 362         }
 363         return ret;
 364 }
 365
 366 /* idmap classic begins here */
 367
 368 enum {
 369         Opt_find_uid, Opt_find_gid, Opt_find_user, Opt_find_group, Opt_find_err
 370 };
 371
 372 static const match_table_t nfs_idmap_tokens = {
 373         { Opt_find_uid, "uid:%s" },
 374         { Opt_find_gid, "gid:%s" },
 375         { Opt_find_user, "user:%s" },
 376         { Opt_find_group, "group:%s" },
 377         { Opt_find_err, NULL }
 378 };
 379
 380 static int nfs_idmap_legacy_upcall(struct key_construction *, const char *, void *);
 381 static ssize_t idmap_pipe_downcall(struct file *, const char __user *,
 382                                    size_t);
 383 static void idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
 384
 385 static const struct rpc_pipe_ops idmap_upcall_ops = {
 386         .upcall         = rpc_pipe_generic_upcall,
 387         .downcall       = idmap_pipe_downcall,
 388         .destroy_msg    = idmap_pipe_destroy_msg,
 389 };
 390
 391 static struct key_type key_type_id_resolver_legacy = {
 392         .name           = "id_legacy",
 393         .instantiate    = user_instantiate,
 394         .match          = user_match,
 395         .revoke         = user_revoke,
 396         .destroy        = user_destroy,
 397         .describe       = user_describe,
 398         .read           = user_read,
 399         .request_key    = nfs_idmap_legacy_upcall,
 400 };
 401
 402 static void __nfs_idmap_unregister(struct rpc_pipe *pipe)
 403 {
 404         if (pipe->dentry)
 405                 rpc_unlink(pipe->dentry);
 406 }
 407
 408 static int __nfs_idmap_register(struct dentry *dir,
 409                                      struct idmap *idmap,
 410                                      struct rpc_pipe *pipe)
 411 {
 412         struct dentry *dentry;
 413
 414         dentry = rpc_mkpipe_dentry(dir, "idmap", idmap, pipe);
 415         if (IS_ERR(dentry))
 416                 return PTR_ERR(dentry);
 417         pipe->dentry = dentry;
 418         return 0;
 419 }
 420
 421 static void nfs_idmap_unregister(struct nfs_client *clp,
 422                                       struct rpc_pipe *pipe)
 423 {
 424         struct net *net = clp->cl_net;
 425         struct super_block *pipefs_sb;
 426
 427         pipefs_sb = rpc_get_sb_net(net);
 428         if (pipefs_sb) {
 429                 __nfs_idmap_unregister(pipe);
 430                 rpc_put_sb_net(net);
 431         }
 432 }
 433
 434 static int nfs_idmap_register(struct nfs_client *clp,
 435                                    struct idmap *idmap,
 436                                    struct rpc_pipe *pipe)
 437 {
 438         struct net *net = clp->cl_net;
 439         struct super_block *pipefs_sb;
 440         int err = 0;
 441
 442         pipefs_sb = rpc_get_sb_net(net);
 443         if (pipefs_sb) {
 444                 if (clp->cl_rpcclient->cl_dentry)
 445                         err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
 446                                                    idmap, pipe);
 447                 rpc_put_sb_net(net);
 448         }
 449         return err;
 450 }
 451
 452 int
 453 nfs_idmap_new(struct nfs_client *clp)
 454 {
 455         struct idmap *idmap;
 456         struct rpc_pipe *pipe;
 457         int error;
 458
 459         BUG_ON(clp->cl_idmap != NULL);
 460
 461         idmap = kzalloc(sizeof(*idmap), GFP_KERNEL);
 462         if (idmap == NULL)
 463                 return -ENOMEM;
 464
 465         pipe = rpc_mkpipe_data(&idmap_upcall_ops, 0);
 466         if (IS_ERR(pipe)) {
 467                 error = PTR_ERR(pipe);
 468                 kfree(idmap);
 469                 return error;
 470         }
 471         error = nfs_idmap_register(clp, idmap, pipe);
 472         if (error) {
 473                 rpc_destroy_pipe_data(pipe);
 474                 kfree(idmap);
 475                 return error;
 476         }
 477         idmap->idmap_pipe = pipe;
 478         mutex_init(&idmap->idmap_mutex);
 479
 480         clp->cl_idmap = idmap;
 481         return 0;
 482 }
 483
 484 void
 485 nfs_idmap_delete(struct nfs_client *clp)
 486 {
 487         struct idmap *idmap = clp->cl_idmap;
 488
 489         if (!idmap)
 490                 return;
 491         nfs_idmap_unregister(clp, idmap->idmap_pipe);
 492         rpc_destroy_pipe_data(idmap->idmap_pipe);
 493         clp->cl_idmap = NULL;
 494         kfree(idmap);
 495 }
 496
 497 static int __rpc_pipefs_event(struct nfs_client *clp, unsigned long event,
 498                               struct super_block *sb)
 499 {
 500         int err = 0;
 501
 502         switch (event) {
 503         case RPC_PIPEFS_MOUNT:
 504                 BUG_ON(clp->cl_rpcclient->cl_dentry == NULL);
 505                 err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
 506                                                 clp->cl_idmap,
 507                                                 clp->cl_idmap->idmap_pipe);
 508                 break;
 509         case RPC_PIPEFS_UMOUNT:
 510                 if (clp->cl_idmap->idmap_pipe) {
 511                         struct dentry *parent;
 512
 513                         parent = clp->cl_idmap->idmap_pipe->dentry->d_parent;
 514                         __nfs_idmap_unregister(clp->cl_idmap->idmap_pipe);
 515                         /*
 516                          * Note: This is a dirty hack. SUNRPC hook has been
 517                          * called already but simple_rmdir() call for the
 518                          * directory returned with error because of idmap pipe
 519                          * inside. Thus now we have to remove this directory
 520                          * here.
 521                          */
 522                         if (rpc_rmdir(parent))
 523                                 printk(KERN_ERR "NFS: %s: failed to remove "
 524                                         "clnt dir!\n", __func__);
 525                 }
 526                 break;
 527         default:
 528                 printk(KERN_ERR "NFS: %s: unknown event: %ld\n", __func__,
 529                         event);
 530                 return -ENOTSUPP;
 531         }
 532         return err;
 533 }
 534
 535 static struct nfs_client *nfs_get_client_for_event(struct net *net, int event)
 536 {
 537         struct nfs_net *nn = net_generic(net, nfs_net_id);
 538         struct dentry *cl_dentry;
 539         struct nfs_client *clp;
 540         int err;
 541
 542 restart:
 543         spin_lock(&nn->nfs_client_lock);
 544         list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
 545                 /* Wait for initialisation to finish */
 546                 if (clp->cl_cons_state == NFS_CS_INITING) {
 547                         atomic_inc(&clp->cl_count);
 548                         spin_unlock(&nn->nfs_client_lock);
 549                         err = nfs_wait_client_init_complete(clp);
 550                         nfs_put_client(clp);
 551                         if (err)
 552                                 return NULL;
 553                         goto restart;
 554                 }
 555                 /* Skip nfs_clients that failed to initialise */
 556                 if (clp->cl_cons_state < 0)
 557                         continue;
 558                 smp_rmb();
 559                 if (clp->rpc_ops != &nfs_v4_clientops)
 560                         continue;
 561                 cl_dentry = clp->cl_idmap->idmap_pipe->dentry;
 562                 if (((event == RPC_PIPEFS_MOUNT) && cl_dentry) ||
 563                     ((event == RPC_PIPEFS_UMOUNT) && !cl_dentry))
 564                         continue;
 565                 atomic_inc(&clp->cl_count);
 566                 spin_unlock(&nn->nfs_client_lock);
 567                 return clp;
 568         }
 569         spin_unlock(&nn->nfs_client_lock);
 570         return NULL;
 571 }
 572
 573 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
 574                             void *ptr)
 575 {
 576         struct super_block *sb = ptr;
 577         struct nfs_client *clp;
 578         int error = 0;
 579
 580         if (!try_module_get(THIS_MODULE))
 581                 return 0;
 582
 583         while ((clp = nfs_get_client_for_event(sb->s_fs_info, event))) {
 584                 error = __rpc_pipefs_event(clp, event, sb);
 585                 nfs_put_client(clp);
 586                 if (error)
 587                         break;
 588         }
 589         module_put(THIS_MODULE);
 590         return error;
 591 }
 592
 593 #define PIPEFS_NFS_PRIO         1
 594
 595 static struct notifier_block nfs_idmap_block = {
 596         .notifier_call  = rpc_pipefs_event,
 597         .priority       = SUNRPC_PIPEFS_NFS_PRIO,
 598 };
 599
 600 int nfs_idmap_init(void)
 601 {
 602         int ret;
 603         ret = nfs_idmap_init_keyring();
 604         if (ret != 0)
 605                 goto out;
 606         ret = rpc_pipefs_notifier_register(&nfs_idmap_block);
 607         if (ret != 0)
 608                 nfs_idmap_quit_keyring();
 609 out:
 610         return ret;
 611 }
 612
 613 void nfs_idmap_quit(void)
 614 {
 615         rpc_pipefs_notifier_unregister(&nfs_idmap_block);
 616         nfs_idmap_quit_keyring();
 617 }
 618
 619 static int nfs_idmap_prepare_message(char *desc, struct idmap_msg *im,
 620                                      struct rpc_pipe_msg *msg)
 621 {
 622         substring_t substr;
 623         int token, ret;
 624
 625         memset(im,  0, sizeof(*im));
 626         memset(msg, 0, sizeof(*msg));
 627
 628         im->im_type = IDMAP_TYPE_GROUP;
 629         token = match_token(desc, nfs_idmap_tokens, &substr);
 630
 631         switch (token) {
 632         case Opt_find_uid:
 633                 im->im_type = IDMAP_TYPE_USER;
 634         case Opt_find_gid:
 635                 im->im_conv = IDMAP_CONV_NAMETOID;
 636                 ret = match_strlcpy(im->im_name, &substr, IDMAP_NAMESZ);
 637                 break;
 638
 639         case Opt_find_user:
 640                 im->im_type = IDMAP_TYPE_USER;
 641         case Opt_find_group:
 642                 im->im_conv = IDMAP_CONV_IDTONAME;
 643                 ret = match_int(&substr, &im->im_id);
 644                 break;
 645
 646         default:
 647                 ret = -EINVAL;
 648                 goto out;
 649         }
 650
 651         msg->data = im;
 652         msg->len  = sizeof(struct idmap_msg);
 653
 654 out:
 655         return ret;
 656 }
 657
 658 static int nfs_idmap_legacy_upcall(struct key_construction *cons,
 659                                    const char *op,
 660                                    void *aux)
 661 {
 662         struct rpc_pipe_msg *msg;
 663         struct idmap_msg *im;
 664         struct idmap *idmap = (struct idmap *)aux;
 665         struct key *key = cons->key;
 666         int ret = -ENOMEM;
 667
 668         /* msg and im are freed in idmap_pipe_destroy_msg */
 669         msg = kmalloc(sizeof(*msg), GFP_KERNEL);
 670         if (!msg)
 671                 goto out0;
 672
 673         im = kmalloc(sizeof(*im), GFP_KERNEL);
 674         if (!im)
 675                 goto out1;
 676
 677         ret = nfs_idmap_prepare_message(key->description, im, msg);
 678         if (ret < 0)
 679                 goto out2;
 680
 681         BUG_ON(idmap->idmap_key_cons != NULL);
 682         idmap->idmap_key_cons = cons;
 683
 684         ret = rpc_queue_upcall(idmap->idmap_pipe, msg);
 685         if (ret < 0)
 686                 goto out2;
 687
 688         return ret;
 689
 690 out2:
 691         kfree(im);
 692 out1:
 693         kfree(msg);
 694 out0:
 695         complete_request_key(cons, ret);
 696         return ret;
 697 }
 698
 699 static int nfs_idmap_instantiate(struct key *key, struct key *authkey, char *data)
 700 {
 701         return key_instantiate_and_link(key, data, strlen(data) + 1,
 702                                         id_resolver_cache->thread_keyring,
 703                                         authkey);
 704 }
 705
 706 static int nfs_idmap_read_message(struct idmap_msg *im, struct key *key, struct key *authkey)
 707 {
 708         char id_str[NFS_UINT_MAXLEN];
 709         int ret = -EINVAL;
 710
 711         switch (im->im_conv) {
 712         case IDMAP_CONV_NAMETOID:
 713                 sprintf(id_str, "%d", im->im_id);
 714                 ret = nfs_idmap_instantiate(key, authkey, id_str);
 715                 break;
 716         case IDMAP_CONV_IDTONAME:
 717                 ret = nfs_idmap_instantiate(key, authkey, im->im_name);
 718                 break;
 719         }
 720
 721         return ret;
 722 }
 723
 724 static ssize_t
 725 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 726 {
 727         struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
 728         struct idmap *idmap = (struct idmap *)rpci->private;
 729         struct key_construction *cons;
 730         struct idmap_msg im;
 731         size_t namelen_in;
 732         int ret;
 733
 734         /* If instantiation is successful, anyone waiting for key construction
 735          * will have been woken up and someone else may now have used
 736          * idmap_key_cons - so after this point we may no longer touch it.
 737          */
 738         cons = ACCESS_ONCE(idmap->idmap_key_cons);
 739         idmap->idmap_key_cons = NULL;
 740
 741         if (mlen != sizeof(im)) {
 742                 ret = -ENOSPC;
 743                 goto out;
 744         }
 745
 746         if (copy_from_user(&im, src, mlen) != 0) {
 747                 ret = -EFAULT;
 748                 goto out;
 749         }
 750
 751         if (!(im.im_status & IDMAP_STATUS_SUCCESS)) {
 752                 ret = mlen;
 753                 complete_request_key(cons, -ENOKEY);
 754                 goto out_incomplete;
 755         }
 756
 757         namelen_in = strnlen(im.im_name, IDMAP_NAMESZ);
 758         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ) {
 759                 ret = -EINVAL;
 760                 goto out;
 761         }
 762
 763         ret = nfs_idmap_read_message(&im, cons->key, cons->authkey);
 764         if (ret >= 0) {
 765                 key_set_timeout(cons->key, nfs_idmap_cache_timeout);
 766                 ret = mlen;
 767         }
 768
 769 out:
 770         complete_request_key(cons, ret);
 771 out_incomplete:
 772         return ret;
 773 }
 774
 775 static void
 776 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 777 {
 778         /* Free memory allocated in nfs_idmap_legacy_upcall() */
 779         kfree(msg->data);
 780         kfree(msg);
 781 }
 782
 783 int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, __u32 *uid)
 784 {
 785         struct idmap *idmap = server->nfs_client->cl_idmap;
 786
 787         if (nfs_map_string_to_numeric(name, namelen, uid))
 788                 return 0;
 789         return nfs_idmap_lookup_id(name, namelen, "uid", uid, idmap);
 790 }
 791
 792 int nfs_map_group_to_gid(const struct nfs_server *server, const char *name, size_t namelen, __u32 *gid)
 793 {
 794         struct idmap *idmap = server->nfs_client->cl_idmap;
 795
 796         if (nfs_map_string_to_numeric(name, namelen, gid))
 797                 return 0;
 798         return nfs_idmap_lookup_id(name, namelen, "gid", gid, idmap);
 799 }
 800
 801 int nfs_map_uid_to_name(const struct nfs_server *server, __u32 uid, char *buf, size_t buflen)
 802 {
 803         struct idmap *idmap = server->nfs_client->cl_idmap;
 804         int ret = -EINVAL;
 805
 806         if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
 807                 ret = nfs_idmap_lookup_name(uid, "user", buf, buflen, idmap);
 808         if (ret < 0)
 809                 ret = nfs_map_numeric_to_string(uid, buf, buflen);
 810         return ret;
 811 }
 812 int nfs_map_gid_to_group(const struct nfs_server *server, __u32 gid, char *buf, size_t buflen)
 813 {
 814         struct idmap *idmap = server->nfs_client->cl_idmap;
 815         int ret = -EINVAL;
 816
 817         if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
 818                 ret = nfs_idmap_lookup_name(gid, "group", buf, buflen, idmap);
 819         if (ret < 0)
 820                 ret = nfs_map_numeric_to_string(gid, buf, buflen);
 821         return ret;
 822 }