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_legacy_upcalldata {
  59         struct rpc_pipe_msg pipe_msg;
  60         struct idmap_msg idmap_msg;
  61         struct key_construction *key_cons;
  62         struct idmap *idmap;
  63 };
  64
  65 struct idmap {
  66         struct rpc_pipe         *idmap_pipe;
  67         struct idmap_legacy_upcalldata *idmap_upcall_data;
  68         struct mutex            idmap_mutex;
  69 };
  70
  71 /**
  72  * nfs_fattr_init_names - initialise the nfs_fattr owner_name/group_name fields
  73  * @fattr: fully initialised struct nfs_fattr
  74  * @owner_name: owner name string cache
  75  * @group_name: group name string cache
  76  */
  77 void nfs_fattr_init_names(struct nfs_fattr *fattr,
  78                 struct nfs4_string *owner_name,
  79                 struct nfs4_string *group_name)
  80 {
  81         fattr->owner_name = owner_name;
  82         fattr->group_name = group_name;
  83 }
  84
  85 static void nfs_fattr_free_owner_name(struct nfs_fattr *fattr)
  86 {
  87         fattr->valid &= ~NFS_ATTR_FATTR_OWNER_NAME;
  88         kfree(fattr->owner_name->data);
  89 }
  90
  91 static void nfs_fattr_free_group_name(struct nfs_fattr *fattr)
  92 {
  93         fattr->valid &= ~NFS_ATTR_FATTR_GROUP_NAME;
  94         kfree(fattr->group_name->data);
  95 }
  96
  97 static bool nfs_fattr_map_owner_name(struct nfs_server *server, struct nfs_fattr *fattr)
  98 {
  99         struct nfs4_string *owner = fattr->owner_name;
 100         kuid_t uid;
 101
 102         if (!(fattr->valid & NFS_ATTR_FATTR_OWNER_NAME))
 103                 return false;
 104         if (nfs_map_name_to_uid(server, owner->data, owner->len, &uid) == 0) {
 105                 fattr->uid = uid;
 106                 fattr->valid |= NFS_ATTR_FATTR_OWNER;
 107         }
 108         return true;
 109 }
 110
 111 static bool nfs_fattr_map_group_name(struct nfs_server *server, struct nfs_fattr *fattr)
 112 {
 113         struct nfs4_string *group = fattr->group_name;
 114         kgid_t gid;
 115
 116         if (!(fattr->valid & NFS_ATTR_FATTR_GROUP_NAME))
 117                 return false;
 118         if (nfs_map_group_to_gid(server, group->data, group->len, &gid) == 0) {
 119                 fattr->gid = gid;
 120                 fattr->valid |= NFS_ATTR_FATTR_GROUP;
 121         }
 122         return true;
 123 }
 124
 125 /**
 126  * nfs_fattr_free_names - free up the NFSv4 owner and group strings
 127  * @fattr: a fully initialised nfs_fattr structure
 128  */
 129 void nfs_fattr_free_names(struct nfs_fattr *fattr)
 130 {
 131         if (fattr->valid & NFS_ATTR_FATTR_OWNER_NAME)
 132                 nfs_fattr_free_owner_name(fattr);
 133         if (fattr->valid & NFS_ATTR_FATTR_GROUP_NAME)
 134                 nfs_fattr_free_group_name(fattr);
 135 }
 136
 137 /**
 138  * nfs_fattr_map_and_free_names - map owner/group strings into uid/gid and free
 139  * @server: pointer to the filesystem nfs_server structure
 140  * @fattr: a fully initialised nfs_fattr structure
 141  *
 142  * This helper maps the cached NFSv4 owner/group strings in fattr into
 143  * their numeric uid/gid equivalents, and then frees the cached strings.
 144  */
 145 void nfs_fattr_map_and_free_names(struct nfs_server *server, struct nfs_fattr *fattr)
 146 {
 147         if (nfs_fattr_map_owner_name(server, fattr))
 148                 nfs_fattr_free_owner_name(fattr);
 149         if (nfs_fattr_map_group_name(server, fattr))
 150                 nfs_fattr_free_group_name(fattr);
 151 }
 152
 153 static int nfs_map_string_to_numeric(const char *name, size_t namelen, __u32 *res)
 154 {
 155         unsigned long val;
 156         char buf[16];
 157
 158         if (memchr(name, '@', namelen) != NULL || namelen >= sizeof(buf))
 159                 return 0;
 160         memcpy(buf, name, namelen);
 161         buf[namelen] = '\0';
 162         if (kstrtoul(buf, 0, &val) != 0)
 163                 return 0;
 164         *res = val;
 165         return 1;
 166 }
 167
 168 static int nfs_map_numeric_to_string(__u32 id, char *buf, size_t buflen)
 169 {
 170         return snprintf(buf, buflen, "%u", id);
 171 }
 172
 173 static struct key_type key_type_id_resolver = {
 174         .name           = "id_resolver",
 175         .instantiate    = user_instantiate,
 176         .match          = user_match,
 177         .revoke         = user_revoke,
 178         .destroy        = user_destroy,
 179         .describe       = user_describe,
 180         .read           = user_read,
 181 };
 182
 183 static int nfs_idmap_init_keyring(void)
 184 {
 185         struct cred *cred;
 186         struct key *keyring;
 187         int ret = 0;
 188
 189         printk(KERN_NOTICE "NFS: Registering the %s key type\n",
 190                 key_type_id_resolver.name);
 191
 192         cred = prepare_kernel_cred(NULL);
 193         if (!cred)
 194                 return -ENOMEM;
 195
 196         keyring = keyring_alloc(".id_resolver",
 197                                 GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
 198                                 (KEY_POS_ALL & ~KEY_POS_SETATTR) |
 199                                 KEY_USR_VIEW | KEY_USR_READ,
 200                                 KEY_ALLOC_NOT_IN_QUOTA, NULL);
 201         if (IS_ERR(keyring)) {
 202                 ret = PTR_ERR(keyring);
 203                 goto failed_put_cred;
 204         }
 205
 206         ret = register_key_type(&key_type_id_resolver);
 207         if (ret < 0)
 208                 goto failed_put_key;
 209
 210         ret = register_key_type(&key_type_id_resolver_legacy);
 211         if (ret < 0)
 212                 goto failed_reg_legacy;
 213
 214         set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
 215         cred->thread_keyring = keyring;
 216         cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
 217         id_resolver_cache = cred;
 218         return 0;
 219
 220 failed_reg_legacy:
 221         unregister_key_type(&key_type_id_resolver);
 222 failed_put_key:
 223         key_put(keyring);
 224 failed_put_cred:
 225         put_cred(cred);
 226         return ret;
 227 }
 228
 229 static void nfs_idmap_quit_keyring(void)
 230 {
 231         key_revoke(id_resolver_cache->thread_keyring);
 232         unregister_key_type(&key_type_id_resolver);
 233         unregister_key_type(&key_type_id_resolver_legacy);
 234         put_cred(id_resolver_cache);
 235 }
 236
 237 /*
 238  * Assemble the description to pass to request_key()
 239  * This function will allocate a new string and update dest to point
 240  * at it.  The caller is responsible for freeing dest.
 241  *
 242  * On error 0 is returned.  Otherwise, the length of dest is returned.
 243  */
 244 static ssize_t nfs_idmap_get_desc(const char *name, size_t namelen,
 245                                 const char *type, size_t typelen, char **desc)
 246 {
 247         char *cp;
 248         size_t desclen = typelen + namelen + 2;
 249
 250         *desc = kmalloc(desclen, GFP_KERNEL);
 251         if (!*desc)
 252                 return -ENOMEM;
 253
 254         cp = *desc;
 255         memcpy(cp, type, typelen);
 256         cp += typelen;
 257         *cp++ = ':';
 258
 259         memcpy(cp, name, namelen);
 260         cp += namelen;
 261         *cp = '\0';
 262         return desclen;
 263 }
 264
 265 static ssize_t nfs_idmap_request_key(struct key_type *key_type,
 266                                      const char *name, size_t namelen,
 267                                      const char *type, void *data,
 268                                      size_t data_size, struct idmap *idmap)
 269 {
 270         const struct cred *saved_cred;
 271         struct key *rkey;
 272         char *desc;
 273         struct user_key_payload *payload;
 274         ssize_t ret;
 275
 276         ret = nfs_idmap_get_desc(name, namelen, type, strlen(type), &desc);
 277         if (ret <= 0)
 278                 goto out;
 279
 280         saved_cred = override_creds(id_resolver_cache);
 281         if (idmap)
 282                 rkey = request_key_with_auxdata(key_type, desc, "", 0, idmap);
 283         else
 284                 rkey = request_key(&key_type_id_resolver, desc, "");
 285         revert_creds(saved_cred);
 286
 287         kfree(desc);
 288         if (IS_ERR(rkey)) {
 289                 ret = PTR_ERR(rkey);
 290                 goto out;
 291         }
 292
 293         rcu_read_lock();
 294         rkey->perm |= KEY_USR_VIEW;
 295
 296         ret = key_validate(rkey);
 297         if (ret < 0)
 298                 goto out_up;
 299
 300         payload = rcu_dereference(rkey->payload.data);
 301         if (IS_ERR_OR_NULL(payload)) {
 302                 ret = PTR_ERR(payload);
 303                 goto out_up;
 304         }
 305
 306         ret = payload->datalen;
 307         if (ret > 0 && ret <= data_size)
 308                 memcpy(data, payload->data, ret);
 309         else
 310                 ret = -EINVAL;
 311
 312 out_up:
 313         rcu_read_unlock();
 314         key_put(rkey);
 315 out:
 316         return ret;
 317 }
 318
 319 static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
 320                                  const char *type, void *data,
 321                                  size_t data_size, struct idmap *idmap)
 322 {
 323         ssize_t ret = nfs_idmap_request_key(&key_type_id_resolver,
 324                                             name, namelen, type, data,
 325                                             data_size, NULL);
 326         if (ret < 0) {
 327                 mutex_lock(&idmap->idmap_mutex);
 328                 ret = nfs_idmap_request_key(&key_type_id_resolver_legacy,
 329                                             name, namelen, type, data,
 330                                             data_size, idmap);
 331                 mutex_unlock(&idmap->idmap_mutex);
 332         }
 333         return ret;
 334 }
 335
 336 /* ID -> Name */
 337 static ssize_t nfs_idmap_lookup_name(__u32 id, const char *type, char *buf,
 338                                      size_t buflen, struct idmap *idmap)
 339 {
 340         char id_str[NFS_UINT_MAXLEN];
 341         int id_len;
 342         ssize_t ret;
 343
 344         id_len = snprintf(id_str, sizeof(id_str), "%u", id);
 345         ret = nfs_idmap_get_key(id_str, id_len, type, buf, buflen, idmap);
 346         if (ret < 0)
 347                 return -EINVAL;
 348         return ret;
 349 }
 350
 351 /* Name -> ID */
 352 static int nfs_idmap_lookup_id(const char *name, size_t namelen, const char *type,
 353                                __u32 *id, struct idmap *idmap)
 354 {
 355         char id_str[NFS_UINT_MAXLEN];
 356         long id_long;
 357         ssize_t data_size;
 358         int ret = 0;
 359
 360         data_size = nfs_idmap_get_key(name, namelen, type, id_str, NFS_UINT_MAXLEN, idmap);
 361         if (data_size <= 0) {
 362                 ret = -EINVAL;
 363         } else {
 364                 ret = kstrtol(id_str, 10, &id_long);
 365                 *id = (__u32)id_long;
 366         }
 367         return ret;
 368 }
 369
 370 /* idmap classic begins here */
 371
 372 enum {
 373         Opt_find_uid, Opt_find_gid, Opt_find_user, Opt_find_group, Opt_find_err
 374 };
 375
 376 static const match_table_t nfs_idmap_tokens = {
 377         { Opt_find_uid, "uid:%s" },
 378         { Opt_find_gid, "gid:%s" },
 379         { Opt_find_user, "user:%s" },
 380         { Opt_find_group, "group:%s" },
 381         { Opt_find_err, NULL }
 382 };
 383
 384 static int nfs_idmap_legacy_upcall(struct key_construction *, const char *, void *);
 385 static ssize_t idmap_pipe_downcall(struct file *, const char __user *,
 386                                    size_t);
 387 static void idmap_release_pipe(struct inode *);
 388 static void idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
 389
 390 static const struct rpc_pipe_ops idmap_upcall_ops = {
 391         .upcall         = rpc_pipe_generic_upcall,
 392         .downcall       = idmap_pipe_downcall,
 393         .release_pipe   = idmap_release_pipe,
 394         .destroy_msg    = idmap_pipe_destroy_msg,
 395 };
 396
 397 static struct key_type key_type_id_resolver_legacy = {
 398         .name           = "id_legacy",
 399         .instantiate    = user_instantiate,
 400         .match          = user_match,
 401         .revoke         = user_revoke,
 402         .destroy        = user_destroy,
 403         .describe       = user_describe,
 404         .read           = user_read,
 405         .request_key    = nfs_idmap_legacy_upcall,
 406 };
 407
 408 static void __nfs_idmap_unregister(struct rpc_pipe *pipe)
 409 {
 410         if (pipe->dentry)
 411                 rpc_unlink(pipe->dentry);
 412 }
 413
 414 static int __nfs_idmap_register(struct dentry *dir,
 415                                      struct idmap *idmap,
 416                                      struct rpc_pipe *pipe)
 417 {
 418         struct dentry *dentry;
 419
 420         dentry = rpc_mkpipe_dentry(dir, "idmap", idmap, pipe);
 421         if (IS_ERR(dentry))
 422                 return PTR_ERR(dentry);
 423         pipe->dentry = dentry;
 424         return 0;
 425 }
 426
 427 static void nfs_idmap_unregister(struct nfs_client *clp,
 428                                       struct rpc_pipe *pipe)
 429 {
 430         struct net *net = clp->cl_net;
 431         struct super_block *pipefs_sb;
 432
 433         pipefs_sb = rpc_get_sb_net(net);
 434         if (pipefs_sb) {
 435                 __nfs_idmap_unregister(pipe);
 436                 rpc_put_sb_net(net);
 437         }
 438 }
 439
 440 static int nfs_idmap_register(struct nfs_client *clp,
 441                                    struct idmap *idmap,
 442                                    struct rpc_pipe *pipe)
 443 {
 444         struct net *net = clp->cl_net;
 445         struct super_block *pipefs_sb;
 446         int err = 0;
 447
 448         pipefs_sb = rpc_get_sb_net(net);
 449         if (pipefs_sb) {
 450                 if (clp->cl_rpcclient->cl_dentry)
 451                         err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
 452                                                    idmap, pipe);
 453                 rpc_put_sb_net(net);
 454         }
 455         return err;
 456 }
 457
 458 int
 459 nfs_idmap_new(struct nfs_client *clp)
 460 {
 461         struct idmap *idmap;
 462         struct rpc_pipe *pipe;
 463         int error;
 464
 465         idmap = kzalloc(sizeof(*idmap), GFP_KERNEL);
 466         if (idmap == NULL)
 467                 return -ENOMEM;
 468
 469         pipe = rpc_mkpipe_data(&idmap_upcall_ops, 0);
 470         if (IS_ERR(pipe)) {
 471                 error = PTR_ERR(pipe);
 472                 kfree(idmap);
 473                 return error;
 474         }
 475         error = nfs_idmap_register(clp, idmap, pipe);
 476         if (error) {
 477                 rpc_destroy_pipe_data(pipe);
 478                 kfree(idmap);
 479                 return error;
 480         }
 481         idmap->idmap_pipe = pipe;
 482         mutex_init(&idmap->idmap_mutex);
 483
 484         clp->cl_idmap = idmap;
 485         return 0;
 486 }
 487
 488 void
 489 nfs_idmap_delete(struct nfs_client *clp)
 490 {
 491         struct idmap *idmap = clp->cl_idmap;
 492
 493         if (!idmap)
 494                 return;
 495         nfs_idmap_unregister(clp, idmap->idmap_pipe);
 496         rpc_destroy_pipe_data(idmap->idmap_pipe);
 497         clp->cl_idmap = NULL;
 498         kfree(idmap);
 499 }
 500
 501 static int __rpc_pipefs_event(struct nfs_client *clp, unsigned long event,
 502                               struct super_block *sb)
 503 {
 504         int err = 0;
 505
 506         switch (event) {
 507         case RPC_PIPEFS_MOUNT:
 508                 err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
 509                                                 clp->cl_idmap,
 510                                                 clp->cl_idmap->idmap_pipe);
 511                 break;
 512         case RPC_PIPEFS_UMOUNT:
 513                 if (clp->cl_idmap->idmap_pipe) {
 514                         struct dentry *parent;
 515
 516                         parent = clp->cl_idmap->idmap_pipe->dentry->d_parent;
 517                         __nfs_idmap_unregister(clp->cl_idmap->idmap_pipe);
 518                         /*
 519                          * Note: This is a dirty hack. SUNRPC hook has been
 520                          * called already but simple_rmdir() call for the
 521                          * directory returned with error because of idmap pipe
 522                          * inside. Thus now we have to remove this directory
 523                          * here.
 524                          */
 525                         if (rpc_rmdir(parent))
 526                                 printk(KERN_ERR "NFS: %s: failed to remove "
 527                                         "clnt dir!\n", __func__);
 528                 }
 529                 break;
 530         default:
 531                 printk(KERN_ERR "NFS: %s: unknown event: %ld\n", __func__,
 532                         event);
 533                 return -ENOTSUPP;
 534         }
 535         return err;
 536 }
 537
 538 static struct nfs_client *nfs_get_client_for_event(struct net *net, int event)
 539 {
 540         struct nfs_net *nn = net_generic(net, nfs_net_id);
 541         struct dentry *cl_dentry;
 542         struct nfs_client *clp;
 543         int err;
 544
 545 restart:
 546         spin_lock(&nn->nfs_client_lock);
 547         list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
 548                 /* Wait for initialisation to finish */
 549                 if (clp->cl_cons_state == NFS_CS_INITING) {
 550                         atomic_inc(&clp->cl_count);
 551                         spin_unlock(&nn->nfs_client_lock);
 552                         err = nfs_wait_client_init_complete(clp);
 553                         nfs_put_client(clp);
 554                         if (err)
 555                                 return NULL;
 556                         goto restart;
 557                 }
 558                 /* Skip nfs_clients that failed to initialise */
 559                 if (clp->cl_cons_state < 0)
 560                         continue;
 561                 smp_rmb();
 562                 if (clp->rpc_ops != &nfs_v4_clientops)
 563                         continue;
 564                 cl_dentry = clp->cl_idmap->idmap_pipe->dentry;
 565                 if (((event == RPC_PIPEFS_MOUNT) && cl_dentry) ||
 566                     ((event == RPC_PIPEFS_UMOUNT) && !cl_dentry))
 567                         continue;
 568                 atomic_inc(&clp->cl_count);
 569                 spin_unlock(&nn->nfs_client_lock);
 570                 return clp;
 571         }
 572         spin_unlock(&nn->nfs_client_lock);
 573         return NULL;
 574 }
 575
 576 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
 577                             void *ptr)
 578 {
 579         struct super_block *sb = ptr;
 580         struct nfs_client *clp;
 581         int error = 0;
 582
 583         if (!try_module_get(THIS_MODULE))
 584                 return 0;
 585
 586         while ((clp = nfs_get_client_for_event(sb->s_fs_info, event))) {
 587                 error = __rpc_pipefs_event(clp, event, sb);
 588                 nfs_put_client(clp);
 589                 if (error)
 590                         break;
 591         }
 592         module_put(THIS_MODULE);
 593         return error;
 594 }
 595
 596 #define PIPEFS_NFS_PRIO         1
 597
 598 static struct notifier_block nfs_idmap_block = {
 599         .notifier_call  = rpc_pipefs_event,
 600         .priority       = SUNRPC_PIPEFS_NFS_PRIO,
 601 };
 602
 603 int nfs_idmap_init(void)
 604 {
 605         int ret;
 606         ret = nfs_idmap_init_keyring();
 607         if (ret != 0)
 608                 goto out;
 609         ret = rpc_pipefs_notifier_register(&nfs_idmap_block);
 610         if (ret != 0)
 611                 nfs_idmap_quit_keyring();
 612 out:
 613         return ret;
 614 }
 615
 616 void nfs_idmap_quit(void)
 617 {
 618         rpc_pipefs_notifier_unregister(&nfs_idmap_block);
 619         nfs_idmap_quit_keyring();
 620 }
 621
 622 static int nfs_idmap_prepare_message(char *desc, struct idmap *idmap,
 623                                      struct idmap_msg *im,
 624                                      struct rpc_pipe_msg *msg)
 625 {
 626         substring_t substr;
 627         int token, ret;
 628
 629         im->im_type = IDMAP_TYPE_GROUP;
 630         token = match_token(desc, nfs_idmap_tokens, &substr);
 631
 632         switch (token) {
 633         case Opt_find_uid:
 634                 im->im_type = IDMAP_TYPE_USER;
 635         case Opt_find_gid:
 636                 im->im_conv = IDMAP_CONV_NAMETOID;
 637                 ret = match_strlcpy(im->im_name, &substr, IDMAP_NAMESZ);
 638                 break;
 639
 640         case Opt_find_user:
 641                 im->im_type = IDMAP_TYPE_USER;
 642         case Opt_find_group:
 643                 im->im_conv = IDMAP_CONV_IDTONAME;
 644                 ret = match_int(&substr, &im->im_id);
 645                 break;
 646
 647         default:
 648                 ret = -EINVAL;
 649                 goto out;
 650         }
 651
 652         msg->data = im;
 653         msg->len  = sizeof(struct idmap_msg);
 654
 655 out:
 656         return ret;
 657 }
 658
 659 static bool
 660 nfs_idmap_prepare_pipe_upcall(struct idmap *idmap,
 661                 struct idmap_legacy_upcalldata *data)
 662 {
 663         if (idmap->idmap_upcall_data != NULL) {
 664                 WARN_ON_ONCE(1);
 665                 return false;
 666         }
 667         idmap->idmap_upcall_data = data;
 668         return true;
 669 }
 670
 671 static void
 672 nfs_idmap_complete_pipe_upcall_locked(struct idmap *idmap, int ret)
 673 {
 674         struct key_construction *cons = idmap->idmap_upcall_data->key_cons;
 675
 676         kfree(idmap->idmap_upcall_data);
 677         idmap->idmap_upcall_data = NULL;
 678         complete_request_key(cons, ret);
 679 }
 680
 681 static void
 682 nfs_idmap_abort_pipe_upcall(struct idmap *idmap, int ret)
 683 {
 684         if (idmap->idmap_upcall_data != NULL)
 685                 nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
 686 }
 687
 688 static int nfs_idmap_legacy_upcall(struct key_construction *cons,
 689                                    const char *op,
 690                                    void *aux)
 691 {
 692         struct idmap_legacy_upcalldata *data;
 693         struct rpc_pipe_msg *msg;
 694         struct idmap_msg *im;
 695         struct idmap *idmap = (struct idmap *)aux;
 696         struct key *key = cons->key;
 697         int ret = -ENOMEM;
 698
 699         /* msg and im are freed in idmap_pipe_destroy_msg */
 700         data = kzalloc(sizeof(*data), GFP_KERNEL);
 701         if (!data)
 702                 goto out1;
 703
 704         msg = &data->pipe_msg;
 705         im = &data->idmap_msg;
 706         data->idmap = idmap;
 707         data->key_cons = cons;
 708
 709         ret = nfs_idmap_prepare_message(key->description, idmap, im, msg);
 710         if (ret < 0)
 711                 goto out2;
 712
 713         ret = -EAGAIN;
 714         if (!nfs_idmap_prepare_pipe_upcall(idmap, data))
 715                 goto out2;
 716
 717         ret = rpc_queue_upcall(idmap->idmap_pipe, msg);
 718         if (ret < 0)
 719                 nfs_idmap_abort_pipe_upcall(idmap, ret);
 720
 721         return ret;
 722 out2:
 723         kfree(data);
 724 out1:
 725         complete_request_key(cons, ret);
 726         return ret;
 727 }
 728
 729 static int nfs_idmap_instantiate(struct key *key, struct key *authkey, char *data, size_t datalen)
 730 {
 731         return key_instantiate_and_link(key, data, datalen,
 732                                         id_resolver_cache->thread_keyring,
 733                                         authkey);
 734 }
 735
 736 static int nfs_idmap_read_and_verify_message(struct idmap_msg *im,
 737                 struct idmap_msg *upcall,
 738                 struct key *key, struct key *authkey)
 739 {
 740         char id_str[NFS_UINT_MAXLEN];
 741         size_t len;
 742         int ret = -ENOKEY;
 743
 744         /* ret = -ENOKEY */
 745         if (upcall->im_type != im->im_type || upcall->im_conv != im->im_conv)
 746                 goto out;
 747         switch (im->im_conv) {
 748         case IDMAP_CONV_NAMETOID:
 749                 if (strcmp(upcall->im_name, im->im_name) != 0)
 750                         break;
 751                 /* Note: here we store the NUL terminator too */
 752                 len = sprintf(id_str, "%d", im->im_id) + 1;
 753                 ret = nfs_idmap_instantiate(key, authkey, id_str, len);
 754                 break;
 755         case IDMAP_CONV_IDTONAME:
 756                 if (upcall->im_id != im->im_id)
 757                         break;
 758                 len = strlen(im->im_name);
 759                 ret = nfs_idmap_instantiate(key, authkey, im->im_name, len);
 760                 break;
 761         default:
 762                 ret = -EINVAL;
 763         }
 764 out:
 765         return ret;
 766 }
 767
 768 static ssize_t
 769 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 770 {
 771         struct rpc_inode *rpci = RPC_I(file_inode(filp));
 772         struct idmap *idmap = (struct idmap *)rpci->private;
 773         struct key_construction *cons;
 774         struct idmap_msg im;
 775         size_t namelen_in;
 776         int ret = -ENOKEY;
 777
 778         /* If instantiation is successful, anyone waiting for key construction
 779          * will have been woken up and someone else may now have used
 780          * idmap_key_cons - so after this point we may no longer touch it.
 781          */
 782         if (idmap->idmap_upcall_data == NULL)
 783                 goto out_noupcall;
 784
 785         cons = idmap->idmap_upcall_data->key_cons;
 786
 787         if (mlen != sizeof(im)) {
 788                 ret = -ENOSPC;
 789                 goto out;
 790         }
 791
 792         if (copy_from_user(&im, src, mlen) != 0) {
 793                 ret = -EFAULT;
 794                 goto out;
 795         }
 796
 797         if (!(im.im_status & IDMAP_STATUS_SUCCESS)) {
 798                 ret = -ENOKEY;
 799                 goto out;
 800         }
 801
 802         namelen_in = strnlen(im.im_name, IDMAP_NAMESZ);
 803         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ) {
 804                 ret = -EINVAL;
 805                 goto out;
 806 }
 807
 808         ret = nfs_idmap_read_and_verify_message(&im,
 809                         &idmap->idmap_upcall_data->idmap_msg,
 810                         cons->key, cons->authkey);
 811         if (ret >= 0) {
 812                 key_set_timeout(cons->key, nfs_idmap_cache_timeout);
 813                 ret = mlen;
 814         }
 815
 816 out:
 817         nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
 818 out_noupcall:
 819         return ret;
 820 }
 821
 822 static void
 823 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 824 {
 825         struct idmap_legacy_upcalldata *data = container_of(msg,
 826                         struct idmap_legacy_upcalldata,
 827                         pipe_msg);
 828         struct idmap *idmap = data->idmap;
 829
 830         if (msg->errno)
 831                 nfs_idmap_abort_pipe_upcall(idmap, msg->errno);
 832 }
 833
 834 static void
 835 idmap_release_pipe(struct inode *inode)
 836 {
 837         struct rpc_inode *rpci = RPC_I(inode);
 838         struct idmap *idmap = (struct idmap *)rpci->private;
 839
 840         nfs_idmap_abort_pipe_upcall(idmap, -EPIPE);
 841 }
 842
 843 int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, kuid_t *uid)
 844 {
 845         struct idmap *idmap = server->nfs_client->cl_idmap;
 846         __u32 id = -1;
 847         int ret = 0;
 848
 849         if (!nfs_map_string_to_numeric(name, namelen, &id))
 850                 ret = nfs_idmap_lookup_id(name, namelen, "uid", &id, idmap);
 851         if (ret == 0) {
 852                 *uid = make_kuid(&init_user_ns, id);
 853                 if (!uid_valid(*uid))
 854                         ret = -ERANGE;
 855         }
 856         return ret;
 857 }
 858
 859 int nfs_map_group_to_gid(const struct nfs_server *server, const char *name, size_t namelen, kgid_t *gid)
 860 {
 861         struct idmap *idmap = server->nfs_client->cl_idmap;
 862         __u32 id = -1;
 863         int ret = 0;
 864
 865         if (!nfs_map_string_to_numeric(name, namelen, &id))
 866                 ret = nfs_idmap_lookup_id(name, namelen, "gid", &id, idmap);
 867         if (ret == 0) {
 868                 *gid = make_kgid(&init_user_ns, id);
 869                 if (!gid_valid(*gid))
 870                         ret = -ERANGE;
 871         }
 872         return ret;
 873 }
 874
 875 int nfs_map_uid_to_name(const struct nfs_server *server, kuid_t uid, char *buf, size_t buflen)
 876 {
 877         struct idmap *idmap = server->nfs_client->cl_idmap;
 878         int ret = -EINVAL;
 879         __u32 id;
 880
 881         id = from_kuid(&init_user_ns, uid);
 882         if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
 883                 ret = nfs_idmap_lookup_name(id, "user", buf, buflen, idmap);
 884         if (ret < 0)
 885                 ret = nfs_map_numeric_to_string(id, buf, buflen);
 886         return ret;
 887 }
 888 int nfs_map_gid_to_group(const struct nfs_server *server, kgid_t gid, char *buf, size_t buflen)
 889 {
 890         struct idmap *idmap = server->nfs_client->cl_idmap;
 891         int ret = -EINVAL;
 892         __u32 id;
 893
 894         id = from_kgid(&init_user_ns, gid);
 895         if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
 896                 ret = nfs_idmap_lookup_name(id, "group", buf, buflen, idmap);
 897         if (ret < 0)
 898                 ret = nfs_map_numeric_to_string(id, buf, buflen);
 899         return ret;
 900 }