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 struct key *nfs_idmap_request_key(const char *name, size_t namelen,
 266                                          const char *type, struct idmap *idmap)
 267 {
 268         char *desc;
 269         struct key *rkey;
 270         ssize_t ret;
 271
 272         ret = nfs_idmap_get_desc(name, namelen, type, strlen(type), &desc);
 273         if (ret <= 0)
 274                 return ERR_PTR(ret);
 275
 276         rkey = request_key(&key_type_id_resolver, desc, "");
 277         if (IS_ERR(rkey)) {
 278                 mutex_lock(&idmap->idmap_mutex);
 279                 rkey = request_key_with_auxdata(&key_type_id_resolver_legacy,
 280                                                 desc, "", 0, idmap);
 281                 mutex_unlock(&idmap->idmap_mutex);
 282         }
 283
 284         kfree(desc);
 285         return rkey;
 286 }
 287
 288 static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
 289                                  const char *type, void *data,
 290                                  size_t data_size, struct idmap *idmap)
 291 {
 292         const struct cred *saved_cred;
 293         struct key *rkey;
 294         struct user_key_payload *payload;
 295         ssize_t ret;
 296
 297         saved_cred = override_creds(id_resolver_cache);
 298         rkey = nfs_idmap_request_key(name, namelen, type, idmap);
 299         revert_creds(saved_cred);
 300
 301         if (IS_ERR(rkey)) {
 302                 ret = PTR_ERR(rkey);
 303                 goto out;
 304         }
 305
 306         rcu_read_lock();
 307         rkey->perm |= KEY_USR_VIEW;
 308
 309         ret = key_validate(rkey);
 310         if (ret < 0)
 311                 goto out_up;
 312
 313         payload = rcu_dereference(rkey->payload.data);
 314         if (IS_ERR_OR_NULL(payload)) {
 315                 ret = PTR_ERR(payload);
 316                 goto out_up;
 317         }
 318
 319         ret = payload->datalen;
 320         if (ret > 0 && ret <= data_size)
 321                 memcpy(data, payload->data, ret);
 322         else
 323                 ret = -EINVAL;
 324
 325 out_up:
 326         rcu_read_unlock();
 327         key_put(rkey);
 328 out:
 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 = kstrtol(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_release_pipe(struct inode *);
 384 static void idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
 385
 386 static const struct rpc_pipe_ops idmap_upcall_ops = {
 387         .upcall         = rpc_pipe_generic_upcall,
 388         .downcall       = idmap_pipe_downcall,
 389         .release_pipe   = idmap_release_pipe,
 390         .destroy_msg    = idmap_pipe_destroy_msg,
 391 };
 392
 393 static struct key_type key_type_id_resolver_legacy = {
 394         .name           = "id_legacy",
 395         .instantiate    = user_instantiate,
 396         .match          = user_match,
 397         .revoke         = user_revoke,
 398         .destroy        = user_destroy,
 399         .describe       = user_describe,
 400         .read           = user_read,
 401         .request_key    = nfs_idmap_legacy_upcall,
 402 };
 403
 404 static void __nfs_idmap_unregister(struct rpc_pipe *pipe)
 405 {
 406         if (pipe->dentry)
 407                 rpc_unlink(pipe->dentry);
 408 }
 409
 410 static int __nfs_idmap_register(struct dentry *dir,
 411                                      struct idmap *idmap,
 412                                      struct rpc_pipe *pipe)
 413 {
 414         struct dentry *dentry;
 415
 416         dentry = rpc_mkpipe_dentry(dir, "idmap", idmap, pipe);
 417         if (IS_ERR(dentry))
 418                 return PTR_ERR(dentry);
 419         pipe->dentry = dentry;
 420         return 0;
 421 }
 422
 423 static void nfs_idmap_unregister(struct nfs_client *clp,
 424                                       struct rpc_pipe *pipe)
 425 {
 426         struct net *net = clp->cl_net;
 427         struct super_block *pipefs_sb;
 428
 429         pipefs_sb = rpc_get_sb_net(net);
 430         if (pipefs_sb) {
 431                 __nfs_idmap_unregister(pipe);
 432                 rpc_put_sb_net(net);
 433         }
 434 }
 435
 436 static int nfs_idmap_register(struct nfs_client *clp,
 437                                    struct idmap *idmap,
 438                                    struct rpc_pipe *pipe)
 439 {
 440         struct net *net = clp->cl_net;
 441         struct super_block *pipefs_sb;
 442         int err = 0;
 443
 444         pipefs_sb = rpc_get_sb_net(net);
 445         if (pipefs_sb) {
 446                 if (clp->cl_rpcclient->cl_dentry)
 447                         err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
 448                                                    idmap, pipe);
 449                 rpc_put_sb_net(net);
 450         }
 451         return err;
 452 }
 453
 454 int
 455 nfs_idmap_new(struct nfs_client *clp)
 456 {
 457         struct idmap *idmap;
 458         struct rpc_pipe *pipe;
 459         int error;
 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                 err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
 505                                                 clp->cl_idmap,
 506                                                 clp->cl_idmap->idmap_pipe);
 507                 break;
 508         case RPC_PIPEFS_UMOUNT:
 509                 if (clp->cl_idmap->idmap_pipe) {
 510                         struct dentry *parent;
 511
 512                         parent = clp->cl_idmap->idmap_pipe->dentry->d_parent;
 513                         __nfs_idmap_unregister(clp->cl_idmap->idmap_pipe);
 514                         /*
 515                          * Note: This is a dirty hack. SUNRPC hook has been
 516                          * called already but simple_rmdir() call for the
 517                          * directory returned with error because of idmap pipe
 518                          * inside. Thus now we have to remove this directory
 519                          * here.
 520                          */
 521                         if (rpc_rmdir(parent))
 522                                 printk(KERN_ERR "NFS: %s: failed to remove "
 523                                         "clnt dir!\n", __func__);
 524                 }
 525                 break;
 526         default:
 527                 printk(KERN_ERR "NFS: %s: unknown event: %ld\n", __func__,
 528                         event);
 529                 return -ENOTSUPP;
 530         }
 531         return err;
 532 }
 533
 534 static struct nfs_client *nfs_get_client_for_event(struct net *net, int event)
 535 {
 536         struct nfs_net *nn = net_generic(net, nfs_net_id);
 537         struct dentry *cl_dentry;
 538         struct nfs_client *clp;
 539         int err;
 540
 541 restart:
 542         spin_lock(&nn->nfs_client_lock);
 543         list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
 544                 /* Wait for initialisation to finish */
 545                 if (clp->cl_cons_state == NFS_CS_INITING) {
 546                         atomic_inc(&clp->cl_count);
 547                         spin_unlock(&nn->nfs_client_lock);
 548                         err = nfs_wait_client_init_complete(clp);
 549                         nfs_put_client(clp);
 550                         if (err)
 551                                 return NULL;
 552                         goto restart;
 553                 }
 554                 /* Skip nfs_clients that failed to initialise */
 555                 if (clp->cl_cons_state < 0)
 556                         continue;
 557                 smp_rmb();
 558                 if (clp->rpc_ops != &nfs_v4_clientops)
 559                         continue;
 560                 cl_dentry = clp->cl_idmap->idmap_pipe->dentry;
 561                 if (((event == RPC_PIPEFS_MOUNT) && cl_dentry) ||
 562                     ((event == RPC_PIPEFS_UMOUNT) && !cl_dentry))
 563                         continue;
 564                 atomic_inc(&clp->cl_count);
 565                 spin_unlock(&nn->nfs_client_lock);
 566                 return clp;
 567         }
 568         spin_unlock(&nn->nfs_client_lock);
 569         return NULL;
 570 }
 571
 572 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
 573                             void *ptr)
 574 {
 575         struct super_block *sb = ptr;
 576         struct nfs_client *clp;
 577         int error = 0;
 578
 579         if (!try_module_get(THIS_MODULE))
 580                 return 0;
 581
 582         while ((clp = nfs_get_client_for_event(sb->s_fs_info, event))) {
 583                 error = __rpc_pipefs_event(clp, event, sb);
 584                 nfs_put_client(clp);
 585                 if (error)
 586                         break;
 587         }
 588         module_put(THIS_MODULE);
 589         return error;
 590 }
 591
 592 #define PIPEFS_NFS_PRIO         1
 593
 594 static struct notifier_block nfs_idmap_block = {
 595         .notifier_call  = rpc_pipefs_event,
 596         .priority       = SUNRPC_PIPEFS_NFS_PRIO,
 597 };
 598
 599 int nfs_idmap_init(void)
 600 {
 601         int ret;
 602         ret = nfs_idmap_init_keyring();
 603         if (ret != 0)
 604                 goto out;
 605         ret = rpc_pipefs_notifier_register(&nfs_idmap_block);
 606         if (ret != 0)
 607                 nfs_idmap_quit_keyring();
 608 out:
 609         return ret;
 610 }
 611
 612 void nfs_idmap_quit(void)
 613 {
 614         rpc_pipefs_notifier_unregister(&nfs_idmap_block);
 615         nfs_idmap_quit_keyring();
 616 }
 617
 618 static int nfs_idmap_prepare_message(char *desc, struct idmap *idmap,
 619                                      struct idmap_msg *im,
 620                                      struct rpc_pipe_msg *msg)
 621 {
 622         substring_t substr;
 623         int token, ret;
 624
 625         im->im_type = IDMAP_TYPE_GROUP;
 626         token = match_token(desc, nfs_idmap_tokens, &substr);
 627
 628         switch (token) {
 629         case Opt_find_uid:
 630                 im->im_type = IDMAP_TYPE_USER;
 631         case Opt_find_gid:
 632                 im->im_conv = IDMAP_CONV_NAMETOID;
 633                 ret = match_strlcpy(im->im_name, &substr, IDMAP_NAMESZ);
 634                 break;
 635
 636         case Opt_find_user:
 637                 im->im_type = IDMAP_TYPE_USER;
 638         case Opt_find_group:
 639                 im->im_conv = IDMAP_CONV_IDTONAME;
 640                 ret = match_int(&substr, &im->im_id);
 641                 break;
 642
 643         default:
 644                 ret = -EINVAL;
 645                 goto out;
 646         }
 647
 648         msg->data = im;
 649         msg->len  = sizeof(struct idmap_msg);
 650
 651 out:
 652         return ret;
 653 }
 654
 655 static bool
 656 nfs_idmap_prepare_pipe_upcall(struct idmap *idmap,
 657                 struct idmap_legacy_upcalldata *data)
 658 {
 659         if (idmap->idmap_upcall_data != NULL) {
 660                 WARN_ON_ONCE(1);
 661                 return false;
 662         }
 663         idmap->idmap_upcall_data = data;
 664         return true;
 665 }
 666
 667 static void
 668 nfs_idmap_complete_pipe_upcall_locked(struct idmap *idmap, int ret)
 669 {
 670         struct key_construction *cons = idmap->idmap_upcall_data->key_cons;
 671
 672         kfree(idmap->idmap_upcall_data);
 673         idmap->idmap_upcall_data = NULL;
 674         complete_request_key(cons, ret);
 675 }
 676
 677 static void
 678 nfs_idmap_abort_pipe_upcall(struct idmap *idmap, int ret)
 679 {
 680         if (idmap->idmap_upcall_data != NULL)
 681                 nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
 682 }
 683
 684 static int nfs_idmap_legacy_upcall(struct key_construction *cons,
 685                                    const char *op,
 686                                    void *aux)
 687 {
 688         struct idmap_legacy_upcalldata *data;
 689         struct rpc_pipe_msg *msg;
 690         struct idmap_msg *im;
 691         struct idmap *idmap = (struct idmap *)aux;
 692         struct key *key = cons->key;
 693         int ret = -ENOMEM;
 694
 695         /* msg and im are freed in idmap_pipe_destroy_msg */
 696         data = kzalloc(sizeof(*data), GFP_KERNEL);
 697         if (!data)
 698                 goto out1;
 699
 700         msg = &data->pipe_msg;
 701         im = &data->idmap_msg;
 702         data->idmap = idmap;
 703         data->key_cons = cons;
 704
 705         ret = nfs_idmap_prepare_message(key->description, idmap, im, msg);
 706         if (ret < 0)
 707                 goto out2;
 708
 709         ret = -EAGAIN;
 710         if (!nfs_idmap_prepare_pipe_upcall(idmap, data))
 711                 goto out2;
 712
 713         ret = rpc_queue_upcall(idmap->idmap_pipe, msg);
 714         if (ret < 0)
 715                 nfs_idmap_abort_pipe_upcall(idmap, ret);
 716
 717         return ret;
 718 out2:
 719         kfree(data);
 720 out1:
 721         complete_request_key(cons, ret);
 722         return ret;
 723 }
 724
 725 static int nfs_idmap_instantiate(struct key *key, struct key *authkey, char *data, size_t datalen)
 726 {
 727         return key_instantiate_and_link(key, data, datalen,
 728                                         id_resolver_cache->thread_keyring,
 729                                         authkey);
 730 }
 731
 732 static int nfs_idmap_read_and_verify_message(struct idmap_msg *im,
 733                 struct idmap_msg *upcall,
 734                 struct key *key, struct key *authkey)
 735 {
 736         char id_str[NFS_UINT_MAXLEN];
 737         size_t len;
 738         int ret = -ENOKEY;
 739
 740         /* ret = -ENOKEY */
 741         if (upcall->im_type != im->im_type || upcall->im_conv != im->im_conv)
 742                 goto out;
 743         switch (im->im_conv) {
 744         case IDMAP_CONV_NAMETOID:
 745                 if (strcmp(upcall->im_name, im->im_name) != 0)
 746                         break;
 747                 /* Note: here we store the NUL terminator too */
 748                 len = sprintf(id_str, "%d", im->im_id) + 1;
 749                 ret = nfs_idmap_instantiate(key, authkey, id_str, len);
 750                 break;
 751         case IDMAP_CONV_IDTONAME:
 752                 if (upcall->im_id != im->im_id)
 753                         break;
 754                 len = strlen(im->im_name);
 755                 ret = nfs_idmap_instantiate(key, authkey, im->im_name, len);
 756                 break;
 757         default:
 758                 ret = -EINVAL;
 759         }
 760 out:
 761         return ret;
 762 }
 763
 764 static ssize_t
 765 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 766 {
 767         struct rpc_inode *rpci = RPC_I(file_inode(filp));
 768         struct idmap *idmap = (struct idmap *)rpci->private;
 769         struct key_construction *cons;
 770         struct idmap_msg im;
 771         size_t namelen_in;
 772         int ret = -ENOKEY;
 773
 774         /* If instantiation is successful, anyone waiting for key construction
 775          * will have been woken up and someone else may now have used
 776          * idmap_key_cons - so after this point we may no longer touch it.
 777          */
 778         if (idmap->idmap_upcall_data == NULL)
 779                 goto out_noupcall;
 780
 781         cons = idmap->idmap_upcall_data->key_cons;
 782
 783         if (mlen != sizeof(im)) {
 784                 ret = -ENOSPC;
 785                 goto out;
 786         }
 787
 788         if (copy_from_user(&im, src, mlen) != 0) {
 789                 ret = -EFAULT;
 790                 goto out;
 791         }
 792
 793         if (!(im.im_status & IDMAP_STATUS_SUCCESS)) {
 794                 ret = -ENOKEY;
 795                 goto out;
 796         }
 797
 798         namelen_in = strnlen(im.im_name, IDMAP_NAMESZ);
 799         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ) {
 800                 ret = -EINVAL;
 801                 goto out;
 802 }
 803
 804         ret = nfs_idmap_read_and_verify_message(&im,
 805                         &idmap->idmap_upcall_data->idmap_msg,
 806                         cons->key, cons->authkey);
 807         if (ret >= 0) {
 808                 key_set_timeout(cons->key, nfs_idmap_cache_timeout);
 809                 ret = mlen;
 810         }
 811
 812 out:
 813         nfs_idmap_complete_pipe_upcall_locked(idmap, ret);
 814 out_noupcall:
 815         return ret;
 816 }
 817
 818 static void
 819 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 820 {
 821         struct idmap_legacy_upcalldata *data = container_of(msg,
 822                         struct idmap_legacy_upcalldata,
 823                         pipe_msg);
 824         struct idmap *idmap = data->idmap;
 825
 826         if (msg->errno)
 827                 nfs_idmap_abort_pipe_upcall(idmap, msg->errno);
 828 }
 829
 830 static void
 831 idmap_release_pipe(struct inode *inode)
 832 {
 833         struct rpc_inode *rpci = RPC_I(inode);
 834         struct idmap *idmap = (struct idmap *)rpci->private;
 835
 836         nfs_idmap_abort_pipe_upcall(idmap, -EPIPE);
 837 }
 838
 839 int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, kuid_t *uid)
 840 {
 841         struct idmap *idmap = server->nfs_client->cl_idmap;
 842         __u32 id = -1;
 843         int ret = 0;
 844
 845         if (!nfs_map_string_to_numeric(name, namelen, &id))
 846                 ret = nfs_idmap_lookup_id(name, namelen, "uid", &id, idmap);
 847         if (ret == 0) {
 848                 *uid = make_kuid(&init_user_ns, id);
 849                 if (!uid_valid(*uid))
 850                         ret = -ERANGE;
 851         }
 852         return ret;
 853 }
 854
 855 int nfs_map_group_to_gid(const struct nfs_server *server, const char *name, size_t namelen, kgid_t *gid)
 856 {
 857         struct idmap *idmap = server->nfs_client->cl_idmap;
 858         __u32 id = -1;
 859         int ret = 0;
 860
 861         if (!nfs_map_string_to_numeric(name, namelen, &id))
 862                 ret = nfs_idmap_lookup_id(name, namelen, "gid", &id, idmap);
 863         if (ret == 0) {
 864                 *gid = make_kgid(&init_user_ns, id);
 865                 if (!gid_valid(*gid))
 866                         ret = -ERANGE;
 867         }
 868         return ret;
 869 }
 870
 871 int nfs_map_uid_to_name(const struct nfs_server *server, kuid_t uid, char *buf, size_t buflen)
 872 {
 873         struct idmap *idmap = server->nfs_client->cl_idmap;
 874         int ret = -EINVAL;
 875         __u32 id;
 876
 877         id = from_kuid(&init_user_ns, uid);
 878         if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
 879                 ret = nfs_idmap_lookup_name(id, "user", buf, buflen, idmap);
 880         if (ret < 0)
 881                 ret = nfs_map_numeric_to_string(id, buf, buflen);
 882         return ret;
 883 }
 884 int nfs_map_gid_to_group(const struct nfs_server *server, kgid_t gid, char *buf, size_t buflen)
 885 {
 886         struct idmap *idmap = server->nfs_client->cl_idmap;
 887         int ret = -EINVAL;
 888         __u32 id;
 889
 890         id = from_kgid(&init_user_ns, gid);
 891         if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
 892                 ret = nfs_idmap_lookup_name(id, "group", buf, buflen, idmap);
 893         if (ret < 0)
 894                 ret = nfs_map_numeric_to_string(id, buf, buflen);
 895         return ret;
 896 }