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 #include "nfs4trace.h"
  53
  54 #define NFS_UINT_MAXLEN 11
  55
  56 static const struct cred *id_resolver_cache;
  57 static struct key_type key_type_id_resolver_legacy;
  58
  59 struct idmap_legacy_upcalldata {
  60         struct rpc_pipe_msg pipe_msg;
  61         struct idmap_msg idmap_msg;
  62         struct key_construction *key_cons;
  63         struct idmap *idmap;
  64 };
  65
  66 struct idmap {
  67         struct rpc_pipe         *idmap_pipe;
  68         struct idmap_legacy_upcalldata *idmap_upcall_data;
  69         struct mutex            idmap_mutex;
  70 };
  71
  72 /**
  73  * nfs_fattr_init_names - initialise the nfs_fattr owner_name/group_name fields
  74  * @fattr: fully initialised struct nfs_fattr
  75  * @owner_name: owner name string cache
  76  * @group_name: group name string cache
  77  */
  78 void nfs_fattr_init_names(struct nfs_fattr *fattr,
  79                 struct nfs4_string *owner_name,
  80                 struct nfs4_string *group_name)
  81 {
  82         fattr->owner_name = owner_name;
  83         fattr->group_name = group_name;
  84 }
  85
  86 static void nfs_fattr_free_owner_name(struct nfs_fattr *fattr)
  87 {
  88         fattr->valid &= ~NFS_ATTR_FATTR_OWNER_NAME;
  89         kfree(fattr->owner_name->data);
  90 }
  91
  92 static void nfs_fattr_free_group_name(struct nfs_fattr *fattr)
  93 {
  94         fattr->valid &= ~NFS_ATTR_FATTR_GROUP_NAME;
  95         kfree(fattr->group_name->data);
  96 }
  97
  98 static bool nfs_fattr_map_owner_name(struct nfs_server *server, struct nfs_fattr *fattr)
  99 {
 100         struct nfs4_string *owner = fattr->owner_name;
 101         kuid_t uid;
 102
 103         if (!(fattr->valid & NFS_ATTR_FATTR_OWNER_NAME))
 104                 return false;
 105         if (nfs_map_name_to_uid(server, owner->data, owner->len, &uid) == 0) {
 106                 fattr->uid = uid;
 107                 fattr->valid |= NFS_ATTR_FATTR_OWNER;
 108         }
 109         return true;
 110 }
 111
 112 static bool nfs_fattr_map_group_name(struct nfs_server *server, struct nfs_fattr *fattr)
 113 {
 114         struct nfs4_string *group = fattr->group_name;
 115         kgid_t gid;
 116
 117         if (!(fattr->valid & NFS_ATTR_FATTR_GROUP_NAME))
 118                 return false;
 119         if (nfs_map_group_to_gid(server, group->data, group->len, &gid) == 0) {
 120                 fattr->gid = gid;
 121                 fattr->valid |= NFS_ATTR_FATTR_GROUP;
 122         }
 123         return true;
 124 }
 125
 126 /**
 127  * nfs_fattr_free_names - free up the NFSv4 owner and group strings
 128  * @fattr: a fully initialised nfs_fattr structure
 129  */
 130 void nfs_fattr_free_names(struct nfs_fattr *fattr)
 131 {
 132         if (fattr->valid & NFS_ATTR_FATTR_OWNER_NAME)
 133                 nfs_fattr_free_owner_name(fattr);
 134         if (fattr->valid & NFS_ATTR_FATTR_GROUP_NAME)
 135                 nfs_fattr_free_group_name(fattr);
 136 }
 137
 138 /**
 139  * nfs_fattr_map_and_free_names - map owner/group strings into uid/gid and free
 140  * @server: pointer to the filesystem nfs_server structure
 141  * @fattr: a fully initialised nfs_fattr structure
 142  *
 143  * This helper maps the cached NFSv4 owner/group strings in fattr into
 144  * their numeric uid/gid equivalents, and then frees the cached strings.
 145  */
 146 void nfs_fattr_map_and_free_names(struct nfs_server *server, struct nfs_fattr *fattr)
 147 {
 148         if (nfs_fattr_map_owner_name(server, fattr))
 149                 nfs_fattr_free_owner_name(fattr);
 150         if (nfs_fattr_map_group_name(server, fattr))
 151                 nfs_fattr_free_group_name(fattr);
 152 }
 153
 154 static int nfs_map_string_to_numeric(const char *name, size_t namelen, __u32 *res)
 155 {
 156         unsigned long val;
 157         char buf[16];
 158
 159         if (memchr(name, '@', namelen) != NULL || namelen >= sizeof(buf))
 160                 return 0;
 161         memcpy(buf, name, namelen);
 162         buf[namelen] = '\0';
 163         if (kstrtoul(buf, 0, &val) != 0)
 164                 return 0;
 165         *res = val;
 166         return 1;
 167 }
 168
 169 static int nfs_map_numeric_to_string(__u32 id, char *buf, size_t buflen)
 170 {
 171         return snprintf(buf, buflen, "%u", id);
 172 }
 173
 174 static struct key_type key_type_id_resolver = {
 175         .name           = "id_resolver",
 176         .instantiate    = user_instantiate,
 177         .match          = user_match,
 178         .revoke         = user_revoke,
 179         .destroy        = user_destroy,
 180         .describe       = user_describe,
 181         .read           = user_read,
 182 };
 183
 184 static int nfs_idmap_init_keyring(void)
 185 {
 186         struct cred *cred;
 187         struct key *keyring;
 188         int ret = 0;
 189
 190         printk(KERN_NOTICE "NFS: Registering the %s key type\n",
 191                 key_type_id_resolver.name);
 192
 193         cred = prepare_kernel_cred(NULL);
 194         if (!cred)
 195                 return -ENOMEM;
 196
 197         keyring = keyring_alloc(".id_resolver",
 198                                 GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
 199                                 (KEY_POS_ALL & ~KEY_POS_SETATTR) |
 200                                 KEY_USR_VIEW | KEY_USR_READ,
 201                                 KEY_ALLOC_NOT_IN_QUOTA, NULL);
 202         if (IS_ERR(keyring)) {
 203                 ret = PTR_ERR(keyring);
 204                 goto failed_put_cred;
 205         }
 206
 207         ret = register_key_type(&key_type_id_resolver);
 208         if (ret < 0)
 209                 goto failed_put_key;
 210
 211         ret = register_key_type(&key_type_id_resolver_legacy);
 212         if (ret < 0)
 213                 goto failed_reg_legacy;
 214
 215         set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
 216         cred->thread_keyring = keyring;
 217         cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
 218         id_resolver_cache = cred;
 219         return 0;
 220
 221 failed_reg_legacy:
 222         unregister_key_type(&key_type_id_resolver);
 223 failed_put_key:
 224         key_put(keyring);
 225 failed_put_cred:
 226         put_cred(cred);
 227         return ret;
 228 }
 229
 230 static void nfs_idmap_quit_keyring(void)
 231 {
 232         key_revoke(id_resolver_cache->thread_keyring);
 233         unregister_key_type(&key_type_id_resolver);
 234         unregister_key_type(&key_type_id_resolver_legacy);
 235         put_cred(id_resolver_cache);
 236 }
 237
 238 /*
 239  * Assemble the description to pass to request_key()
 240  * This function will allocate a new string and update dest to point
 241  * at it.  The caller is responsible for freeing dest.
 242  *
 243  * On error 0 is returned.  Otherwise, the length of dest is returned.
 244  */
 245 static ssize_t nfs_idmap_get_desc(const char *name, size_t namelen,
 246                                 const char *type, size_t typelen, char **desc)
 247 {
 248         char *cp;
 249         size_t desclen = typelen + namelen + 2;
 250
 251         *desc = kmalloc(desclen, GFP_KERNEL);
 252         if (!*desc)
 253                 return -ENOMEM;
 254
 255         cp = *desc;
 256         memcpy(cp, type, typelen);
 257         cp += typelen;
 258         *cp++ = ':';
 259
 260         memcpy(cp, name, namelen);
 261         cp += namelen;
 262         *cp = '\0';
 263         return desclen;
 264 }
 265
 266 static struct key *nfs_idmap_request_key(const char *name, size_t namelen,
 267                                          const char *type, struct idmap *idmap)
 268 {
 269         char *desc;
 270         struct key *rkey;
 271         ssize_t ret;
 272
 273         ret = nfs_idmap_get_desc(name, namelen, type, strlen(type), &desc);
 274         if (ret <= 0)
 275                 return ERR_PTR(ret);
 276
 277         rkey = request_key(&key_type_id_resolver, desc, "");
 278         if (IS_ERR(rkey)) {
 279                 mutex_lock(&idmap->idmap_mutex);
 280                 rkey = request_key_with_auxdata(&key_type_id_resolver_legacy,
 281                                                 desc, "", 0, idmap);
 282                 mutex_unlock(&idmap->idmap_mutex);
 283         }
 284
 285         kfree(desc);
 286         return rkey;
 287 }
 288
 289 static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
 290                                  const char *type, void *data,
 291                                  size_t data_size, struct idmap *idmap)
 292 {
 293         const struct cred *saved_cred;
 294         struct key *rkey;
 295         struct user_key_payload *payload;
 296         ssize_t ret;
 297
 298         saved_cred = override_creds(id_resolver_cache);
 299         rkey = nfs_idmap_request_key(name, namelen, type, idmap);
 300         revert_creds(saved_cred);
 301
 302         if (IS_ERR(rkey)) {
 303                 ret = PTR_ERR(rkey);
 304                 goto out;
 305         }
 306
 307         rcu_read_lock();
 308         rkey->perm |= KEY_USR_VIEW;
 309
 310         ret = key_validate(rkey);
 311         if (ret < 0)
 312                 goto out_up;
 313
 314         payload = rcu_dereference(rkey->payload.rcudata);
 315         if (IS_ERR_OR_NULL(payload)) {
 316                 ret = PTR_ERR(payload);
 317                 goto out_up;
 318         }
 319
 320         ret = payload->datalen;
 321         if (ret > 0 && ret <= data_size)
 322                 memcpy(data, payload->data, ret);
 323         else
 324                 ret = -EINVAL;
 325
 326 out_up:
 327         rcu_read_unlock();
 328         key_put(rkey);
 329 out:
 330         return ret;
 331 }
 332
 333 /* ID -> Name */
 334 static ssize_t nfs_idmap_lookup_name(__u32 id, const char *type, char *buf,
 335                                      size_t buflen, struct idmap *idmap)
 336 {
 337         char id_str[NFS_UINT_MAXLEN];
 338         int id_len;
 339         ssize_t ret;
 340
 341         id_len = snprintf(id_str, sizeof(id_str), "%u", id);
 342         ret = nfs_idmap_get_key(id_str, id_len, type, buf, buflen, idmap);
 343         if (ret < 0)
 344                 return -EINVAL;
 345         return ret;
 346 }
 347
 348 /* Name -> ID */
 349 static int nfs_idmap_lookup_id(const char *name, size_t namelen, const char *type,
 350                                __u32 *id, struct idmap *idmap)
 351 {
 352         char id_str[NFS_UINT_MAXLEN];
 353         long id_long;
 354         ssize_t data_size;
 355         int ret = 0;
 356
 357         data_size = nfs_idmap_get_key(name, namelen, type, id_str, NFS_UINT_MAXLEN, idmap);
 358         if (data_size <= 0) {
 359                 ret = -EINVAL;
 360         } else {
 361                 ret = kstrtol(id_str, 10, &id_long);
 362                 *id = (__u32)id_long;
 363         }
 364         return ret;
 365 }
 366
 367 /* idmap classic begins here */
 368
 369 enum {
 370         Opt_find_uid, Opt_find_gid, Opt_find_user, Opt_find_group, Opt_find_err
 371 };
 372
 373 static const match_table_t nfs_idmap_tokens = {
 374         { Opt_find_uid, "uid:%s" },
 375         { Opt_find_gid, "gid:%s" },
 376         { Opt_find_user, "user:%s" },
 377         { Opt_find_group, "group:%s" },
 378         { Opt_find_err, NULL }
 379 };
 380
 381 static int nfs_idmap_legacy_upcall(struct key_construction *, const char *, void *);
 382 static ssize_t idmap_pipe_downcall(struct file *, const char __user *,
 383                                    size_t);
 384 static void idmap_release_pipe(struct inode *);
 385 static void idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
 386
 387 static const struct rpc_pipe_ops idmap_upcall_ops = {
 388         .upcall         = rpc_pipe_generic_upcall,
 389         .downcall       = idmap_pipe_downcall,
 390         .release_pipe   = idmap_release_pipe,
 391         .destroy_msg    = idmap_pipe_destroy_msg,
 392 };
 393
 394 static struct key_type key_type_id_resolver_legacy = {
 395         .name           = "id_legacy",
 396         .instantiate    = user_instantiate,
 397         .match          = user_match,
 398         .revoke         = user_revoke,
 399         .destroy        = user_destroy,
 400         .describe       = user_describe,
 401         .read           = user_read,
 402         .request_key    = nfs_idmap_legacy_upcall,
 403 };
 404
 405 static void __nfs_idmap_unregister(struct rpc_pipe *pipe)
 406 {
 407         if (pipe->dentry) {
 408                 rpc_unlink(pipe->dentry);
 409                 pipe->dentry = NULL;
 410         }
 411 }
 412
 413 static int __nfs_idmap_register(struct dentry *dir,
 414                                      struct idmap *idmap,
 415                                      struct rpc_pipe *pipe)
 416 {
 417         struct dentry *dentry;
 418
 419         dentry = rpc_mkpipe_dentry(dir, "idmap", idmap, pipe);
 420         if (IS_ERR(dentry))
 421                 return PTR_ERR(dentry);
 422         pipe->dentry = dentry;
 423         return 0;
 424 }
 425
 426 static void nfs_idmap_unregister(struct nfs_client *clp,
 427                                       struct rpc_pipe *pipe)
 428 {
 429         struct net *net = clp->cl_net;
 430         struct super_block *pipefs_sb;
 431
 432         pipefs_sb = rpc_get_sb_net(net);
 433         if (pipefs_sb) {
 434                 __nfs_idmap_unregister(pipe);
 435                 rpc_put_sb_net(net);
 436         }
 437 }
 438
 439 static int nfs_idmap_register(struct nfs_client *clp,
 440                                    struct idmap *idmap,
 441                                    struct rpc_pipe *pipe)
 442 {
 443         struct net *net = clp->cl_net;
 444         struct super_block *pipefs_sb;
 445         int err = 0;
 446
 447         pipefs_sb = rpc_get_sb_net(net);
 448         if (pipefs_sb) {
 449                 if (clp->cl_rpcclient->cl_dentry)
 450                         err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
 451                                                    idmap, pipe);
 452                 rpc_put_sb_net(net);
 453         }
 454         return err;
 455 }
 456
 457 int
 458 nfs_idmap_new(struct nfs_client *clp)
 459 {
 460         struct idmap *idmap;
 461         struct rpc_pipe *pipe;
 462         int error;
 463
 464         idmap = kzalloc(sizeof(*idmap), GFP_KERNEL);
 465         if (idmap == NULL)
 466                 return -ENOMEM;
 467
 468         pipe = rpc_mkpipe_data(&idmap_upcall_ops, 0);
 469         if (IS_ERR(pipe)) {
 470                 error = PTR_ERR(pipe);
 471                 kfree(idmap);
 472                 return error;
 473         }
 474         error = nfs_idmap_register(clp, idmap, pipe);
 475         if (error) {
 476                 rpc_destroy_pipe_data(pipe);
 477                 kfree(idmap);
 478                 return error;
 479         }
 480         idmap->idmap_pipe = pipe;
 481         mutex_init(&idmap->idmap_mutex);
 482
 483         clp->cl_idmap = idmap;
 484         return 0;
 485 }
 486
 487 void
 488 nfs_idmap_delete(struct nfs_client *clp)
 489 {
 490         struct idmap *idmap = clp->cl_idmap;
 491
 492         if (!idmap)
 493                 return;
 494         nfs_idmap_unregister(clp, idmap->idmap_pipe);
 495         rpc_destroy_pipe_data(idmap->idmap_pipe);
 496         clp->cl_idmap = NULL;
 497         kfree(idmap);
 498 }
 499
 500 static int __rpc_pipefs_event(struct nfs_client *clp, unsigned long event,
 501                               struct super_block *sb)
 502 {
 503         int err = 0;
 504
 505         switch (event) {
 506         case RPC_PIPEFS_MOUNT:
 507                 err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
 508                                                 clp->cl_idmap,
 509                                                 clp->cl_idmap->idmap_pipe);
 510                 break;
 511         case RPC_PIPEFS_UMOUNT:
 512                 if (clp->cl_idmap->idmap_pipe) {
 513                         struct dentry *parent;
 514
 515                         parent = clp->cl_idmap->idmap_pipe->dentry->d_parent;
 516                         __nfs_idmap_unregister(clp->cl_idmap->idmap_pipe);
 517                         /*
 518                          * Note: This is a dirty hack. SUNRPC hook has been
 519                          * called already but simple_rmdir() call for the
 520                          * directory returned with error because of idmap pipe
 521                          * inside. Thus now we have to remove this directory
 522                          * here.
 523                          */
 524                         if (rpc_rmdir(parent))
 525                                 printk(KERN_ERR "NFS: %s: failed to remove "
 526                                         "clnt dir!\n", __func__);
 527                 }
 528                 break;
 529         default:
 530                 printk(KERN_ERR "NFS: %s: unknown event: %ld\n", __func__,
 531                         event);
 532                 return -ENOTSUPP;
 533         }
 534         return err;
 535 }
 536
 537 static struct nfs_client *nfs_get_client_for_event(struct net *net, int event)
 538 {
 539         struct nfs_net *nn = net_generic(net, nfs_net_id);
 540         struct dentry *cl_dentry;
 541         struct nfs_client *clp;
 542         int err;
 543
 544 restart:
 545         spin_lock(&nn->nfs_client_lock);
 546         list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
 547                 /* Wait for initialisation to finish */
 548                 if (clp->cl_cons_state == NFS_CS_INITING) {
 549                         atomic_inc(&clp->cl_count);
 550                         spin_unlock(&nn->nfs_client_lock);
 551                         err = nfs_wait_client_init_complete(clp);
 552                         nfs_put_client(clp);
 553                         if (err)
 554                                 return NULL;
 555                         goto restart;
 556                 }
 557                 /* Skip nfs_clients that failed to initialise */
 558                 if (clp->cl_cons_state < 0)
 559                         continue;
 560                 smp_rmb();
 561                 if (clp->rpc_ops != &nfs_v4_clientops)
 562                         continue;
 563                 cl_dentry = clp->cl_idmap->idmap_pipe->dentry;
 564                 if (((event == RPC_PIPEFS_MOUNT) && cl_dentry) ||
 565                     ((event == RPC_PIPEFS_UMOUNT) && !cl_dentry))
 566                         continue;
 567                 atomic_inc(&clp->cl_count);
 568                 spin_unlock(&nn->nfs_client_lock);
 569                 return clp;
 570         }
 571         spin_unlock(&nn->nfs_client_lock);
 572         return NULL;
 573 }
 574
 575 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
 576                             void *ptr)
 577 {
 578         struct super_block *sb = ptr;
 579         struct nfs_client *clp;
 580         int error = 0;
 581
 582         if (!try_module_get(THIS_MODULE))
 583                 return 0;
 584
 585         while ((clp = nfs_get_client_for_event(sb->s_fs_info, event))) {
 586                 error = __rpc_pipefs_event(clp, event, sb);
 587                 nfs_put_client(clp);
 588                 if (error)
 589                         break;
 590         }
 591         module_put(THIS_MODULE);
 592         return error;
 593 }
 594
 595 #define PIPEFS_NFS_PRIO         1
 596
 597 static struct notifier_block nfs_idmap_block = {
 598         .notifier_call  = rpc_pipefs_event,
 599         .priority       = SUNRPC_PIPEFS_NFS_PRIO,
 600 };
 601
 602 int nfs_idmap_init(void)
 603 {
 604         int ret;
 605         ret = nfs_idmap_init_keyring();
 606         if (ret != 0)
 607                 goto out;
 608         ret = rpc_pipefs_notifier_register(&nfs_idmap_block);
 609         if (ret != 0)
 610                 nfs_idmap_quit_keyring();
 611 out:
 612         return ret;
 613 }
 614
 615 void nfs_idmap_quit(void)
 616 {
 617         rpc_pipefs_notifier_unregister(&nfs_idmap_block);
 618         nfs_idmap_quit_keyring();
 619 }
 620
 621 static int nfs_idmap_prepare_message(char *desc, struct idmap *idmap,
 622                                      struct idmap_msg *im,
 623                                      struct rpc_pipe_msg *msg)
 624 {
 625         substring_t substr;
 626         int token, ret;
 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 bool
 659 nfs_idmap_prepare_pipe_upcall(struct idmap *idmap,
 660                 struct idmap_legacy_upcalldata *data)
 661 {
 662         if (idmap->idmap_upcall_data != NULL) {
 663                 WARN_ON_ONCE(1);
 664                 return false;
 665         }
 666         idmap->idmap_upcall_data = data;
 667         return true;
 668 }
 669
 670 static void
 671 nfs_idmap_complete_pipe_upcall_locked(struct idmap *idmap, int ret)
 672 {
 673         struct key_construction *cons = idmap->idmap_upcall_data->key_cons;
 674
 675         kfree(idmap->idmap_upcall_data);
 676         idmap->idmap_upcall_data = NULL;
 677         complete_request_key(cons, ret);
 678 }
 679
 680 static void
 681 nfs_idmap_abort_pipe_upcall(struct idmap *idmap, int ret)
 682 {
 683         if (idmap->idmap_upcall_data != NULL)
 684                 nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
 685 }
 686
 687 static int nfs_idmap_legacy_upcall(struct key_construction *cons,
 688                                    const char *op,
 689                                    void *aux)
 690 {
 691         struct idmap_legacy_upcalldata *data;
 692         struct rpc_pipe_msg *msg;
 693         struct idmap_msg *im;
 694         struct idmap *idmap = (struct idmap *)aux;
 695         struct key *key = cons->key;
 696         int ret = -ENOMEM;
 697
 698         /* msg and im are freed in idmap_pipe_destroy_msg */
 699         data = kzalloc(sizeof(*data), GFP_KERNEL);
 700         if (!data)
 701                 goto out1;
 702
 703         msg = &data->pipe_msg;
 704         im = &data->idmap_msg;
 705         data->idmap = idmap;
 706         data->key_cons = cons;
 707
 708         ret = nfs_idmap_prepare_message(key->description, idmap, im, msg);
 709         if (ret < 0)
 710                 goto out2;
 711
 712         ret = -EAGAIN;
 713         if (!nfs_idmap_prepare_pipe_upcall(idmap, data))
 714                 goto out2;
 715
 716         ret = rpc_queue_upcall(idmap->idmap_pipe, msg);
 717         if (ret < 0)
 718                 nfs_idmap_abort_pipe_upcall(idmap, ret);
 719
 720         return ret;
 721 out2:
 722         kfree(data);
 723 out1:
 724         complete_request_key(cons, ret);
 725         return ret;
 726 }
 727
 728 static int nfs_idmap_instantiate(struct key *key, struct key *authkey, char *data, size_t datalen)
 729 {
 730         return key_instantiate_and_link(key, data, datalen,
 731                                         id_resolver_cache->thread_keyring,
 732                                         authkey);
 733 }
 734
 735 static int nfs_idmap_read_and_verify_message(struct idmap_msg *im,
 736                 struct idmap_msg *upcall,
 737                 struct key *key, struct key *authkey)
 738 {
 739         char id_str[NFS_UINT_MAXLEN];
 740         size_t len;
 741         int ret = -ENOKEY;
 742
 743         /* ret = -ENOKEY */
 744         if (upcall->im_type != im->im_type || upcall->im_conv != im->im_conv)
 745                 goto out;
 746         switch (im->im_conv) {
 747         case IDMAP_CONV_NAMETOID:
 748                 if (strcmp(upcall->im_name, im->im_name) != 0)
 749                         break;
 750                 /* Note: here we store the NUL terminator too */
 751                 len = sprintf(id_str, "%d", im->im_id) + 1;
 752                 ret = nfs_idmap_instantiate(key, authkey, id_str, len);
 753                 break;
 754         case IDMAP_CONV_IDTONAME:
 755                 if (upcall->im_id != im->im_id)
 756                         break;
 757                 len = strlen(im->im_name);
 758                 ret = nfs_idmap_instantiate(key, authkey, im->im_name, len);
 759                 break;
 760         default:
 761                 ret = -EINVAL;
 762         }
 763 out:
 764         return ret;
 765 }
 766
 767 static ssize_t
 768 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 769 {
 770         struct rpc_inode *rpci = RPC_I(file_inode(filp));
 771         struct idmap *idmap = (struct idmap *)rpci->private;
 772         struct key_construction *cons;
 773         struct idmap_msg im;
 774         size_t namelen_in;
 775         int ret = -ENOKEY;
 776
 777         /* If instantiation is successful, anyone waiting for key construction
 778          * will have been woken up and someone else may now have used
 779          * idmap_key_cons - so after this point we may no longer touch it.
 780          */
 781         if (idmap->idmap_upcall_data == NULL)
 782                 goto out_noupcall;
 783
 784         cons = idmap->idmap_upcall_data->key_cons;
 785
 786         if (mlen != sizeof(im)) {
 787                 ret = -ENOSPC;
 788                 goto out;
 789         }
 790
 791         if (copy_from_user(&im, src, mlen) != 0) {
 792                 ret = -EFAULT;
 793                 goto out;
 794         }
 795
 796         if (!(im.im_status & IDMAP_STATUS_SUCCESS)) {
 797                 ret = -ENOKEY;
 798                 goto out;
 799         }
 800
 801         namelen_in = strnlen(im.im_name, IDMAP_NAMESZ);
 802         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ) {
 803                 ret = -EINVAL;
 804                 goto out;
 805 }
 806
 807         ret = nfs_idmap_read_and_verify_message(&im,
 808                         &idmap->idmap_upcall_data->idmap_msg,
 809                         cons->key, cons->authkey);
 810         if (ret >= 0) {
 811                 key_set_timeout(cons->key, nfs_idmap_cache_timeout);
 812                 ret = mlen;
 813         }
 814
 815 out:
 816         nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
 817 out_noupcall:
 818         return ret;
 819 }
 820
 821 static void
 822 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 823 {
 824         struct idmap_legacy_upcalldata *data = container_of(msg,
 825                         struct idmap_legacy_upcalldata,
 826                         pipe_msg);
 827         struct idmap *idmap = data->idmap;
 828
 829         if (msg->errno)
 830                 nfs_idmap_abort_pipe_upcall(idmap, msg->errno);
 831 }
 832
 833 static void
 834 idmap_release_pipe(struct inode *inode)
 835 {
 836         struct rpc_inode *rpci = RPC_I(inode);
 837         struct idmap *idmap = (struct idmap *)rpci->private;
 838
 839         nfs_idmap_abort_pipe_upcall(idmap, -EPIPE);
 840 }
 841
 842 int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, kuid_t *uid)
 843 {
 844         struct idmap *idmap = server->nfs_client->cl_idmap;
 845         __u32 id = -1;
 846         int ret = 0;
 847
 848         if (!nfs_map_string_to_numeric(name, namelen, &id))
 849                 ret = nfs_idmap_lookup_id(name, namelen, "uid", &id, idmap);
 850         if (ret == 0) {
 851                 *uid = make_kuid(&init_user_ns, id);
 852                 if (!uid_valid(*uid))
 853                         ret = -ERANGE;
 854         }
 855         trace_nfs4_map_name_to_uid(name, namelen, id, ret);
 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         trace_nfs4_map_group_to_gid(name, namelen, id, ret);
 873         return ret;
 874 }
 875
 876 int nfs_map_uid_to_name(const struct nfs_server *server, kuid_t uid, char *buf, size_t buflen)
 877 {
 878         struct idmap *idmap = server->nfs_client->cl_idmap;
 879         int ret = -EINVAL;
 880         __u32 id;
 881
 882         id = from_kuid(&init_user_ns, uid);
 883         if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
 884                 ret = nfs_idmap_lookup_name(id, "user", buf, buflen, idmap);
 885         if (ret < 0)
 886                 ret = nfs_map_numeric_to_string(id, buf, buflen);
 887         trace_nfs4_map_uid_to_name(buf, ret, id, ret);
 888         return ret;
 889 }
 890 int nfs_map_gid_to_group(const struct nfs_server *server, kgid_t gid, char *buf, size_t buflen)
 891 {
 892         struct idmap *idmap = server->nfs_client->cl_idmap;
 893         int ret = -EINVAL;
 894         __u32 id;
 895
 896         id = from_kgid(&init_user_ns, gid);
 897         if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
 898                 ret = nfs_idmap_lookup_name(id, "group", buf, buflen, idmap);
 899         if (ret < 0)
 900                 ret = nfs_map_numeric_to_string(id, buf, buflen);
 901         trace_nfs4_map_gid_to_group(buf, ret, id, ret);
 902         return ret;
 903 }