nfs4idmap.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 <net/net_namespace.h>
  40 #include <linux/sunrpc/rpc_pipe_fs.h>
  41 #include <linux/nfs_fs.h>
  42 #include <linux/nfs_fs_sb.h>
  43 #include <linux/key.h>
  44 #include <linux/keyctl.h>
  45 #include <linux/key-type.h>
  46 #include <keys/user-type.h>
  47 #include <keys/request_key_auth-type.h>
  48 #include <linux/module.h>
  49 #include <linux/user_namespace.h>
  50
  51 #include "internal.h"
  52 #include "netns.h"
  53 #include "nfs4idmap.h"
  54 #include "nfs4trace.h"
  55
  56 #define NFS_UINT_MAXLEN 11
  57
  58 static const struct cred *id_resolver_cache;
  59 static struct key_type key_type_id_resolver_legacy;
  60
  61 struct idmap_legacy_upcalldata {
  62         struct rpc_pipe_msg pipe_msg;
  63         struct idmap_msg idmap_msg;
  64         struct key      *authkey;
  65         struct idmap *idmap;
  66 };
  67
  68 struct idmap {
  69         struct rpc_pipe_dir_object idmap_pdo;
  70         struct rpc_pipe         *idmap_pipe;
  71         struct idmap_legacy_upcalldata *idmap_upcall_data;
  72         struct mutex            idmap_mutex;
  73         struct user_namespace   *user_ns;
  74 };
  75
  76 static struct user_namespace *idmap_userns(const struct idmap *idmap)
  77 {
  78         if (idmap && idmap->user_ns)
  79                 return idmap->user_ns;
  80         return &init_user_ns;
  81 }
  82
  83 /**
  84  * nfs_fattr_init_names - initialise the nfs_fattr owner_name/group_name fields
  85  * @fattr: fully initialised struct nfs_fattr
  86  * @owner_name: owner name string cache
  87  * @group_name: group name string cache
  88  */
  89 void nfs_fattr_init_names(struct nfs_fattr *fattr,
  90                 struct nfs4_string *owner_name,
  91                 struct nfs4_string *group_name)
  92 {
  93         fattr->owner_name = owner_name;
  94         fattr->group_name = group_name;
  95 }
  96
  97 static void nfs_fattr_free_owner_name(struct nfs_fattr *fattr)
  98 {
  99         fattr->valid &= ~NFS_ATTR_FATTR_OWNER_NAME;
 100         kfree(fattr->owner_name->data);
 101 }
 102
 103 static void nfs_fattr_free_group_name(struct nfs_fattr *fattr)
 104 {
 105         fattr->valid &= ~NFS_ATTR_FATTR_GROUP_NAME;
 106         kfree(fattr->group_name->data);
 107 }
 108
 109 static bool nfs_fattr_map_owner_name(struct nfs_server *server, struct nfs_fattr *fattr)
 110 {
 111         struct nfs4_string *owner = fattr->owner_name;
 112         kuid_t uid;
 113
 114         if (!(fattr->valid & NFS_ATTR_FATTR_OWNER_NAME))
 115                 return false;
 116         if (nfs_map_name_to_uid(server, owner->data, owner->len, &uid) == 0) {
 117                 fattr->uid = uid;
 118                 fattr->valid |= NFS_ATTR_FATTR_OWNER;
 119         }
 120         return true;
 121 }
 122
 123 static bool nfs_fattr_map_group_name(struct nfs_server *server, struct nfs_fattr *fattr)
 124 {
 125         struct nfs4_string *group = fattr->group_name;
 126         kgid_t gid;
 127
 128         if (!(fattr->valid & NFS_ATTR_FATTR_GROUP_NAME))
 129                 return false;
 130         if (nfs_map_group_to_gid(server, group->data, group->len, &gid) == 0) {
 131                 fattr->gid = gid;
 132                 fattr->valid |= NFS_ATTR_FATTR_GROUP;
 133         }
 134         return true;
 135 }
 136
 137 /**
 138  * nfs_fattr_free_names - free up the NFSv4 owner and group strings
 139  * @fattr: a fully initialised nfs_fattr structure
 140  */
 141 void nfs_fattr_free_names(struct nfs_fattr *fattr)
 142 {
 143         if (fattr->valid & NFS_ATTR_FATTR_OWNER_NAME)
 144                 nfs_fattr_free_owner_name(fattr);
 145         if (fattr->valid & NFS_ATTR_FATTR_GROUP_NAME)
 146                 nfs_fattr_free_group_name(fattr);
 147 }
 148
 149 /**
 150  * nfs_fattr_map_and_free_names - map owner/group strings into uid/gid and free
 151  * @server: pointer to the filesystem nfs_server structure
 152  * @fattr: a fully initialised nfs_fattr structure
 153  *
 154  * This helper maps the cached NFSv4 owner/group strings in fattr into
 155  * their numeric uid/gid equivalents, and then frees the cached strings.
 156  */
 157 void nfs_fattr_map_and_free_names(struct nfs_server *server, struct nfs_fattr *fattr)
 158 {
 159         if (nfs_fattr_map_owner_name(server, fattr))
 160                 nfs_fattr_free_owner_name(fattr);
 161         if (nfs_fattr_map_group_name(server, fattr))
 162                 nfs_fattr_free_group_name(fattr);
 163 }
 164
 165 int nfs_map_string_to_numeric(const char *name, size_t namelen, __u32 *res)
 166 {
 167         unsigned long val;
 168         char buf[16];
 169
 170         if (memchr(name, '@', namelen) != NULL || namelen >= sizeof(buf))
 171                 return 0;
 172         memcpy(buf, name, namelen);
 173         buf[namelen] = '\0';
 174         if (kstrtoul(buf, 0, &val) != 0)
 175                 return 0;
 176         *res = val;
 177         return 1;
 178 }
 179 EXPORT_SYMBOL_GPL(nfs_map_string_to_numeric);
 180
 181 static int nfs_map_numeric_to_string(__u32 id, char *buf, size_t buflen)
 182 {
 183         return snprintf(buf, buflen, "%u", id);
 184 }
 185
 186 static struct key_type key_type_id_resolver = {
 187         .name           = "id_resolver",
 188         .preparse       = user_preparse,
 189         .free_preparse  = user_free_preparse,
 190         .instantiate    = generic_key_instantiate,
 191         .revoke         = user_revoke,
 192         .destroy        = user_destroy,
 193         .describe       = user_describe,
 194         .read           = user_read,
 195 };
 196
 197 int nfs_idmap_init(void)
 198 {
 199         struct cred *cred;
 200         struct key *keyring;
 201         int ret = 0;
 202
 203         printk(KERN_NOTICE "NFS: Registering the %s key type\n",
 204                 key_type_id_resolver.name);
 205
 206         cred = prepare_kernel_cred(NULL);
 207         if (!cred)
 208                 return -ENOMEM;
 209
 210         keyring = keyring_alloc(".id_resolver",
 211                                 GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
 212                                 (KEY_POS_ALL & ~KEY_POS_SETATTR) |
 213                                 KEY_USR_VIEW | KEY_USR_READ,
 214                                 KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
 215         if (IS_ERR(keyring)) {
 216                 ret = PTR_ERR(keyring);
 217                 goto failed_put_cred;
 218         }
 219
 220         ret = register_key_type(&key_type_id_resolver);
 221         if (ret < 0)
 222                 goto failed_put_key;
 223
 224         ret = register_key_type(&key_type_id_resolver_legacy);
 225         if (ret < 0)
 226                 goto failed_reg_legacy;
 227
 228         set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
 229         cred->thread_keyring = keyring;
 230         cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
 231         id_resolver_cache = cred;
 232         return 0;
 233
 234 failed_reg_legacy:
 235         unregister_key_type(&key_type_id_resolver);
 236 failed_put_key:
 237         key_put(keyring);
 238 failed_put_cred:
 239         put_cred(cred);
 240         return ret;
 241 }
 242
 243 void nfs_idmap_quit(void)
 244 {
 245         key_revoke(id_resolver_cache->thread_keyring);
 246         unregister_key_type(&key_type_id_resolver);
 247         unregister_key_type(&key_type_id_resolver_legacy);
 248         put_cred(id_resolver_cache);
 249 }
 250
 251 /*
 252  * Assemble the description to pass to request_key()
 253  * This function will allocate a new string and update dest to point
 254  * at it.  The caller is responsible for freeing dest.
 255  *
 256  * On error 0 is returned.  Otherwise, the length of dest is returned.
 257  */
 258 static ssize_t nfs_idmap_get_desc(const char *name, size_t namelen,
 259                                 const char *type, size_t typelen, char **desc)
 260 {
 261         char *cp;
 262         size_t desclen = typelen + namelen + 2;
 263
 264         *desc = kmalloc(desclen, GFP_KERNEL);
 265         if (!*desc)
 266                 return -ENOMEM;
 267
 268         cp = *desc;
 269         memcpy(cp, type, typelen);
 270         cp += typelen;
 271         *cp++ = ':';
 272
 273         memcpy(cp, name, namelen);
 274         cp += namelen;
 275         *cp = '\0';
 276         return desclen;
 277 }
 278
 279 static struct key *nfs_idmap_request_key(const char *name, size_t namelen,
 280                                          const char *type, struct idmap *idmap)
 281 {
 282         char *desc;
 283         struct key *rkey = ERR_PTR(-EAGAIN);
 284         ssize_t ret;
 285
 286         ret = nfs_idmap_get_desc(name, namelen, type, strlen(type), &desc);
 287         if (ret < 0)
 288                 return ERR_PTR(ret);
 289
 290         if (!idmap->user_ns || idmap->user_ns == &init_user_ns)
 291                 rkey = request_key(&key_type_id_resolver, desc, "");
 292         if (IS_ERR(rkey)) {
 293                 mutex_lock(&idmap->idmap_mutex);
 294                 rkey = request_key_with_auxdata(&key_type_id_resolver_legacy,
 295                                                 desc, NULL, "", 0, idmap);
 296                 mutex_unlock(&idmap->idmap_mutex);
 297         }
 298         if (!IS_ERR(rkey))
 299                 set_bit(KEY_FLAG_ROOT_CAN_INVAL, &rkey->flags);
 300
 301         kfree(desc);
 302         return rkey;
 303 }
 304
 305 static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
 306                                  const char *type, void *data,
 307                                  size_t data_size, struct idmap *idmap)
 308 {
 309         const struct cred *saved_cred;
 310         struct key *rkey;
 311         const struct user_key_payload *payload;
 312         ssize_t ret;
 313
 314         saved_cred = override_creds(id_resolver_cache);
 315         rkey = nfs_idmap_request_key(name, namelen, type, idmap);
 316         revert_creds(saved_cred);
 317
 318         if (IS_ERR(rkey)) {
 319                 ret = PTR_ERR(rkey);
 320                 goto out;
 321         }
 322
 323         rcu_read_lock();
 324         rkey->perm |= KEY_USR_VIEW;
 325
 326         ret = key_validate(rkey);
 327         if (ret < 0)
 328                 goto out_up;
 329
 330         payload = user_key_payload_rcu(rkey);
 331         if (IS_ERR_OR_NULL(payload)) {
 332                 ret = PTR_ERR(payload);
 333                 goto out_up;
 334         }
 335
 336         ret = payload->datalen;
 337         if (ret > 0 && ret <= data_size)
 338                 memcpy(data, payload->data, ret);
 339         else
 340                 ret = -EINVAL;
 341
 342 out_up:
 343         rcu_read_unlock();
 344         key_put(rkey);
 345 out:
 346         return ret;
 347 }
 348
 349 /* ID -> Name */
 350 static ssize_t nfs_idmap_lookup_name(__u32 id, const char *type, char *buf,
 351                                      size_t buflen, struct idmap *idmap)
 352 {
 353         char id_str[NFS_UINT_MAXLEN];
 354         int id_len;
 355         ssize_t ret;
 356
 357         id_len = nfs_map_numeric_to_string(id, id_str, sizeof(id_str));
 358         ret = nfs_idmap_get_key(id_str, id_len, type, buf, buflen, idmap);
 359         if (ret < 0)
 360                 return -EINVAL;
 361         return ret;
 362 }
 363
 364 /* Name -> ID */
 365 static int nfs_idmap_lookup_id(const char *name, size_t namelen, const char *type,
 366                                __u32 *id, struct idmap *idmap)
 367 {
 368         char id_str[NFS_UINT_MAXLEN];
 369         long id_long;
 370         ssize_t data_size;
 371         int ret = 0;
 372
 373         data_size = nfs_idmap_get_key(name, namelen, type, id_str, NFS_UINT_MAXLEN, idmap);
 374         if (data_size <= 0) {
 375                 ret = -EINVAL;
 376         } else {
 377                 ret = kstrtol(id_str, 10, &id_long);
 378                 if (!ret)
 379                         *id = (__u32)id_long;
 380         }
 381         return ret;
 382 }
 383
 384 /* idmap classic begins here */
 385
 386 enum {
 387         Opt_find_uid, Opt_find_gid, Opt_find_user, Opt_find_group, Opt_find_err
 388 };
 389
 390 static const match_table_t nfs_idmap_tokens = {
 391         { Opt_find_uid, "uid:%s" },
 392         { Opt_find_gid, "gid:%s" },
 393         { Opt_find_user, "user:%s" },
 394         { Opt_find_group, "group:%s" },
 395         { Opt_find_err, NULL }
 396 };
 397
 398 static int nfs_idmap_legacy_upcall(struct key *, void *);
 399 static ssize_t idmap_pipe_downcall(struct file *, const char __user *,
 400                                    size_t);
 401 static void idmap_release_pipe(struct inode *);
 402 static void idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
 403
 404 static const struct rpc_pipe_ops idmap_upcall_ops = {
 405         .upcall         = rpc_pipe_generic_upcall,
 406         .downcall       = idmap_pipe_downcall,
 407         .release_pipe   = idmap_release_pipe,
 408         .destroy_msg    = idmap_pipe_destroy_msg,
 409 };
 410
 411 static struct key_type key_type_id_resolver_legacy = {
 412         .name           = "id_legacy",
 413         .preparse       = user_preparse,
 414         .free_preparse  = user_free_preparse,
 415         .instantiate    = generic_key_instantiate,
 416         .revoke         = user_revoke,
 417         .destroy        = user_destroy,
 418         .describe       = user_describe,
 419         .read           = user_read,
 420         .request_key    = nfs_idmap_legacy_upcall,
 421 };
 422
 423 static void nfs_idmap_pipe_destroy(struct dentry *dir,
 424                 struct rpc_pipe_dir_object *pdo)
 425 {
 426         struct idmap *idmap = pdo->pdo_data;
 427         struct rpc_pipe *pipe = idmap->idmap_pipe;
 428
 429         if (pipe->dentry) {
 430                 rpc_unlink(pipe->dentry);
 431                 pipe->dentry = NULL;
 432         }
 433 }
 434
 435 static int nfs_idmap_pipe_create(struct dentry *dir,
 436                 struct rpc_pipe_dir_object *pdo)
 437 {
 438         struct idmap *idmap = pdo->pdo_data;
 439         struct rpc_pipe *pipe = idmap->idmap_pipe;
 440         struct dentry *dentry;
 441
 442         dentry = rpc_mkpipe_dentry(dir, "idmap", idmap, pipe);
 443         if (IS_ERR(dentry))
 444                 return PTR_ERR(dentry);
 445         pipe->dentry = dentry;
 446         return 0;
 447 }
 448
 449 static const struct rpc_pipe_dir_object_ops nfs_idmap_pipe_dir_object_ops = {
 450         .create = nfs_idmap_pipe_create,
 451         .destroy = nfs_idmap_pipe_destroy,
 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         mutex_init(&idmap->idmap_mutex);
 466         idmap->user_ns = get_user_ns(clp->cl_rpcclient->cl_cred->user_ns);
 467
 468         rpc_init_pipe_dir_object(&idmap->idmap_pdo,
 469                         &nfs_idmap_pipe_dir_object_ops,
 470                         idmap);
 471
 472         pipe = rpc_mkpipe_data(&idmap_upcall_ops, 0);
 473         if (IS_ERR(pipe)) {
 474                 error = PTR_ERR(pipe);
 475                 goto err;
 476         }
 477         idmap->idmap_pipe = pipe;
 478
 479         error = rpc_add_pipe_dir_object(clp->cl_net,
 480                         &clp->cl_rpcclient->cl_pipedir_objects,
 481                         &idmap->idmap_pdo);
 482         if (error)
 483                 goto err_destroy_pipe;
 484
 485         clp->cl_idmap = idmap;
 486         return 0;
 487 err_destroy_pipe:
 488         rpc_destroy_pipe_data(idmap->idmap_pipe);
 489 err:
 490         put_user_ns(idmap->user_ns);
 491         kfree(idmap);
 492         return error;
 493 }
 494
 495 void
 496 nfs_idmap_delete(struct nfs_client *clp)
 497 {
 498         struct idmap *idmap = clp->cl_idmap;
 499
 500         if (!idmap)
 501                 return;
 502         clp->cl_idmap = NULL;
 503         rpc_remove_pipe_dir_object(clp->cl_net,
 504                         &clp->cl_rpcclient->cl_pipedir_objects,
 505                         &idmap->idmap_pdo);
 506         rpc_destroy_pipe_data(idmap->idmap_pipe);
 507         put_user_ns(idmap->user_ns);
 508         kfree(idmap);
 509 }
 510
 511 static int nfs_idmap_prepare_message(char *desc, struct idmap *idmap,
 512                                      struct idmap_msg *im,
 513                                      struct rpc_pipe_msg *msg)
 514 {
 515         substring_t substr;
 516         int token, ret;
 517
 518         im->im_type = IDMAP_TYPE_GROUP;
 519         token = match_token(desc, nfs_idmap_tokens, &substr);
 520
 521         switch (token) {
 522         case Opt_find_uid:
 523                 im->im_type = IDMAP_TYPE_USER;
 524                 fallthrough;
 525         case Opt_find_gid:
 526                 im->im_conv = IDMAP_CONV_NAMETOID;
 527                 ret = match_strlcpy(im->im_name, &substr, IDMAP_NAMESZ);
 528                 break;
 529
 530         case Opt_find_user:
 531                 im->im_type = IDMAP_TYPE_USER;
 532                 fallthrough;
 533         case Opt_find_group:
 534                 im->im_conv = IDMAP_CONV_IDTONAME;
 535                 ret = match_int(&substr, &im->im_id);
 536                 if (ret)
 537                         goto out;
 538                 break;
 539
 540         default:
 541                 ret = -EINVAL;
 542                 goto out;
 543         }
 544
 545         msg->data = im;
 546         msg->len  = sizeof(struct idmap_msg);
 547
 548 out:
 549         return ret;
 550 }
 551
 552 static bool
 553 nfs_idmap_prepare_pipe_upcall(struct idmap *idmap,
 554                 struct idmap_legacy_upcalldata *data)
 555 {
 556         if (idmap->idmap_upcall_data != NULL) {
 557                 WARN_ON_ONCE(1);
 558                 return false;
 559         }
 560         idmap->idmap_upcall_data = data;
 561         return true;
 562 }
 563
 564 static void nfs_idmap_complete_pipe_upcall(struct idmap_legacy_upcalldata *data,
 565                                            int ret)
 566 {
 567         complete_request_key(data->authkey, ret);
 568         key_put(data->authkey);
 569         kfree(data);
 570 }
 571
 572 static void nfs_idmap_abort_pipe_upcall(struct idmap *idmap,
 573                                         struct idmap_legacy_upcalldata *data,
 574                                         int ret)
 575 {
 576         if (cmpxchg(&idmap->idmap_upcall_data, data, NULL) == data)
 577                 nfs_idmap_complete_pipe_upcall(data, ret);
 578 }
 579
 580 static int nfs_idmap_legacy_upcall(struct key *authkey, void *aux)
 581 {
 582         struct idmap_legacy_upcalldata *data;
 583         struct request_key_auth *rka = get_request_key_auth(authkey);
 584         struct rpc_pipe_msg *msg;
 585         struct idmap_msg *im;
 586         struct idmap *idmap = aux;
 587         struct key *key = rka->target_key;
 588         int ret = -ENOKEY;
 589
 590         if (!aux)
 591                 goto out1;
 592
 593         /* msg and im are freed in idmap_pipe_destroy_msg */
 594         ret = -ENOMEM;
 595         data = kzalloc(sizeof(*data), GFP_KERNEL);
 596         if (!data)
 597                 goto out1;
 598
 599         msg = &data->pipe_msg;
 600         im = &data->idmap_msg;
 601         data->idmap = idmap;
 602         data->authkey = key_get(authkey);
 603
 604         ret = nfs_idmap_prepare_message(key->description, idmap, im, msg);
 605         if (ret < 0)
 606                 goto out2;
 607
 608         ret = -EAGAIN;
 609         if (!nfs_idmap_prepare_pipe_upcall(idmap, data))
 610                 goto out2;
 611
 612         ret = rpc_queue_upcall(idmap->idmap_pipe, msg);
 613         if (ret < 0)
 614                 nfs_idmap_abort_pipe_upcall(idmap, data, ret);
 615
 616         return ret;
 617 out2:
 618         kfree(data);
 619 out1:
 620         complete_request_key(authkey, ret);
 621         return ret;
 622 }
 623
 624 static int nfs_idmap_instantiate(struct key *key, struct key *authkey, char *data, size_t datalen)
 625 {
 626         return key_instantiate_and_link(key, data, datalen,
 627                                         id_resolver_cache->thread_keyring,
 628                                         authkey);
 629 }
 630
 631 static int nfs_idmap_read_and_verify_message(struct idmap_msg *im,
 632                 struct idmap_msg *upcall,
 633                 struct key *key, struct key *authkey)
 634 {
 635         char id_str[NFS_UINT_MAXLEN];
 636         size_t len;
 637         int ret = -ENOKEY;
 638
 639         /* ret = -ENOKEY */
 640         if (upcall->im_type != im->im_type || upcall->im_conv != im->im_conv)
 641                 goto out;
 642         switch (im->im_conv) {
 643         case IDMAP_CONV_NAMETOID:
 644                 if (strcmp(upcall->im_name, im->im_name) != 0)
 645                         break;
 646                 /* Note: here we store the NUL terminator too */
 647                 len = 1 + nfs_map_numeric_to_string(im->im_id, id_str,
 648                                                     sizeof(id_str));
 649                 ret = nfs_idmap_instantiate(key, authkey, id_str, len);
 650                 break;
 651         case IDMAP_CONV_IDTONAME:
 652                 if (upcall->im_id != im->im_id)
 653                         break;
 654                 len = strlen(im->im_name);
 655                 ret = nfs_idmap_instantiate(key, authkey, im->im_name, len);
 656                 break;
 657         default:
 658                 ret = -EINVAL;
 659         }
 660 out:
 661         return ret;
 662 }
 663
 664 static ssize_t
 665 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 666 {
 667         struct request_key_auth *rka;
 668         struct rpc_inode *rpci = RPC_I(file_inode(filp));
 669         struct idmap *idmap = (struct idmap *)rpci->private;
 670         struct idmap_legacy_upcalldata *data;
 671         struct key *authkey;
 672         struct idmap_msg im;
 673         size_t namelen_in;
 674         int ret = -ENOKEY;
 675
 676         /* If instantiation is successful, anyone waiting for key construction
 677          * will have been woken up and someone else may now have used
 678          * idmap_key_cons - so after this point we may no longer touch it.
 679          */
 680         data = xchg(&idmap->idmap_upcall_data, NULL);
 681         if (data == NULL)
 682                 goto out_noupcall;
 683
 684         authkey = data->authkey;
 685         rka = get_request_key_auth(authkey);
 686
 687         if (mlen != sizeof(im)) {
 688                 ret = -ENOSPC;
 689                 goto out;
 690         }
 691
 692         if (copy_from_user(&im, src, mlen) != 0) {
 693                 ret = -EFAULT;
 694                 goto out;
 695         }
 696
 697         if (!(im.im_status & IDMAP_STATUS_SUCCESS)) {
 698                 ret = -ENOKEY;
 699                 goto out;
 700         }
 701
 702         namelen_in = strnlen(im.im_name, IDMAP_NAMESZ);
 703         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ) {
 704                 ret = -EINVAL;
 705                 goto out;
 706         }
 707
 708         ret = nfs_idmap_read_and_verify_message(&im, &data->idmap_msg,
 709                                                 rka->target_key, authkey);
 710         if (ret >= 0) {
 711                 key_set_timeout(rka->target_key, nfs_idmap_cache_timeout);
 712                 ret = mlen;
 713         }
 714
 715 out:
 716         nfs_idmap_complete_pipe_upcall(data, ret);
 717 out_noupcall:
 718         return ret;
 719 }
 720
 721 static void
 722 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 723 {
 724         struct idmap_legacy_upcalldata *data = container_of(msg,
 725                         struct idmap_legacy_upcalldata,
 726                         pipe_msg);
 727         struct idmap *idmap = data->idmap;
 728
 729         if (msg->errno)
 730                 nfs_idmap_abort_pipe_upcall(idmap, data, msg->errno);
 731 }
 732
 733 static void
 734 idmap_release_pipe(struct inode *inode)
 735 {
 736         struct rpc_inode *rpci = RPC_I(inode);
 737         struct idmap *idmap = (struct idmap *)rpci->private;
 738         struct idmap_legacy_upcalldata *data;
 739
 740         data = xchg(&idmap->idmap_upcall_data, NULL);
 741         if (data)
 742                 nfs_idmap_complete_pipe_upcall(data, -EPIPE);
 743 }
 744
 745 int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, kuid_t *uid)
 746 {
 747         struct idmap *idmap = server->nfs_client->cl_idmap;
 748         __u32 id = -1;
 749         int ret = 0;
 750
 751         if (!nfs_map_string_to_numeric(name, namelen, &id))
 752                 ret = nfs_idmap_lookup_id(name, namelen, "uid", &id, idmap);
 753         if (ret == 0) {
 754                 *uid = make_kuid(idmap_userns(idmap), id);
 755                 if (!uid_valid(*uid))
 756                         ret = -ERANGE;
 757         }
 758         trace_nfs4_map_name_to_uid(name, namelen, id, ret);
 759         return ret;
 760 }
 761
 762 int nfs_map_group_to_gid(const struct nfs_server *server, const char *name, size_t namelen, kgid_t *gid)
 763 {
 764         struct idmap *idmap = server->nfs_client->cl_idmap;
 765         __u32 id = -1;
 766         int ret = 0;
 767
 768         if (!nfs_map_string_to_numeric(name, namelen, &id))
 769                 ret = nfs_idmap_lookup_id(name, namelen, "gid", &id, idmap);
 770         if (ret == 0) {
 771                 *gid = make_kgid(idmap_userns(idmap), id);
 772                 if (!gid_valid(*gid))
 773                         ret = -ERANGE;
 774         }
 775         trace_nfs4_map_group_to_gid(name, namelen, id, ret);
 776         return ret;
 777 }
 778
 779 int nfs_map_uid_to_name(const struct nfs_server *server, kuid_t uid, char *buf, size_t buflen)
 780 {
 781         struct idmap *idmap = server->nfs_client->cl_idmap;
 782         int ret = -EINVAL;
 783         __u32 id;
 784
 785         id = from_kuid_munged(idmap_userns(idmap), uid);
 786         if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
 787                 ret = nfs_idmap_lookup_name(id, "user", buf, buflen, idmap);
 788         if (ret < 0)
 789                 ret = nfs_map_numeric_to_string(id, buf, buflen);
 790         trace_nfs4_map_uid_to_name(buf, ret, id, ret);
 791         return ret;
 792 }
 793 int nfs_map_gid_to_group(const struct nfs_server *server, kgid_t gid, char *buf, size_t buflen)
 794 {
 795         struct idmap *idmap = server->nfs_client->cl_idmap;
 796         int ret = -EINVAL;
 797         __u32 id;
 798
 799         id = from_kgid_munged(idmap_userns(idmap), gid);
 800         if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
 801                 ret = nfs_idmap_lookup_name(id, "group", buf, buflen, idmap);
 802         if (ret < 0)
 803                 ret = nfs_map_numeric_to_string(id, buf, buflen);
 804         trace_nfs4_map_gid_to_group(buf, ret, id, ret);
 805         return ret;
 806 }