linux/fs/nfs/idmap.c
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   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
  55static const struct cred *id_resolver_cache;
  56static struct key_type key_type_id_resolver_legacy;
  57
  58struct idmap {
  59        struct rpc_pipe         *idmap_pipe;
  60        struct key_construction *idmap_key_cons;
  61        struct mutex            idmap_mutex;
  62};
  63
  64struct idmap_legacy_upcalldata {
  65        struct rpc_pipe_msg pipe_msg;
  66        struct idmap_msg idmap_msg;
  67        struct idmap *idmap;
  68};
  69
  70/**
  71 * nfs_fattr_init_names - initialise the nfs_fattr owner_name/group_name fields
  72 * @fattr: fully initialised struct nfs_fattr
  73 * @owner_name: owner name string cache
  74 * @group_name: group name string cache
  75 */
  76void nfs_fattr_init_names(struct nfs_fattr *fattr,
  77                struct nfs4_string *owner_name,
  78                struct nfs4_string *group_name)
  79{
  80        fattr->owner_name = owner_name;
  81        fattr->group_name = group_name;
  82}
  83
  84static void nfs_fattr_free_owner_name(struct nfs_fattr *fattr)
  85{
  86        fattr->valid &= ~NFS_ATTR_FATTR_OWNER_NAME;
  87        kfree(fattr->owner_name->data);
  88}
  89
  90static void nfs_fattr_free_group_name(struct nfs_fattr *fattr)
  91{
  92        fattr->valid &= ~NFS_ATTR_FATTR_GROUP_NAME;
  93        kfree(fattr->group_name->data);
  94}
  95
  96static bool nfs_fattr_map_owner_name(struct nfs_server *server, struct nfs_fattr *fattr)
  97{
  98        struct nfs4_string *owner = fattr->owner_name;
  99        __u32 uid;
 100
 101        if (!(fattr->valid & NFS_ATTR_FATTR_OWNER_NAME))
 102                return false;
 103        if (nfs_map_name_to_uid(server, owner->data, owner->len, &uid) == 0) {
 104                fattr->uid = uid;
 105                fattr->valid |= NFS_ATTR_FATTR_OWNER;
 106        }
 107        return true;
 108}
 109
 110static bool nfs_fattr_map_group_name(struct nfs_server *server, struct nfs_fattr *fattr)
 111{
 112        struct nfs4_string *group = fattr->group_name;
 113        __u32 gid;
 114
 115        if (!(fattr->valid & NFS_ATTR_FATTR_GROUP_NAME))
 116                return false;
 117        if (nfs_map_group_to_gid(server, group->data, group->len, &gid) == 0) {
 118                fattr->gid = gid;
 119                fattr->valid |= NFS_ATTR_FATTR_GROUP;
 120        }
 121        return true;
 122}
 123
 124/**
 125 * nfs_fattr_free_names - free up the NFSv4 owner and group strings
 126 * @fattr: a fully initialised nfs_fattr structure
 127 */
 128void nfs_fattr_free_names(struct nfs_fattr *fattr)
 129{
 130        if (fattr->valid & NFS_ATTR_FATTR_OWNER_NAME)
 131                nfs_fattr_free_owner_name(fattr);
 132        if (fattr->valid & NFS_ATTR_FATTR_GROUP_NAME)
 133                nfs_fattr_free_group_name(fattr);
 134}
 135
 136/**
 137 * nfs_fattr_map_and_free_names - map owner/group strings into uid/gid and free
 138 * @server: pointer to the filesystem nfs_server structure
 139 * @fattr: a fully initialised nfs_fattr structure
 140 *
 141 * This helper maps the cached NFSv4 owner/group strings in fattr into
 142 * their numeric uid/gid equivalents, and then frees the cached strings.
 143 */
 144void nfs_fattr_map_and_free_names(struct nfs_server *server, struct nfs_fattr *fattr)
 145{
 146        if (nfs_fattr_map_owner_name(server, fattr))
 147                nfs_fattr_free_owner_name(fattr);
 148        if (nfs_fattr_map_group_name(server, fattr))
 149                nfs_fattr_free_group_name(fattr);
 150}
 151
 152static int nfs_map_string_to_numeric(const char *name, size_t namelen, __u32 *res)
 153{
 154        unsigned long val;
 155        char buf[16];
 156
 157        if (memchr(name, '@', namelen) != NULL || namelen >= sizeof(buf))
 158                return 0;
 159        memcpy(buf, name, namelen);
 160        buf[namelen] = '\0';
 161        if (strict_strtoul(buf, 0, &val) != 0)
 162                return 0;
 163        *res = val;
 164        return 1;
 165}
 166
 167static int nfs_map_numeric_to_string(__u32 id, char *buf, size_t buflen)
 168{
 169        return snprintf(buf, buflen, "%u", id);
 170}
 171
 172static struct key_type key_type_id_resolver = {
 173        .name           = "id_resolver",
 174        .instantiate    = user_instantiate,
 175        .match          = user_match,
 176        .revoke         = user_revoke,
 177        .destroy        = user_destroy,
 178        .describe       = user_describe,
 179        .read           = user_read,
 180};
 181
 182static int nfs_idmap_init_keyring(void)
 183{
 184        struct cred *cred;
 185        struct key *keyring;
 186        int ret = 0;
 187
 188        printk(KERN_NOTICE "NFS: Registering the %s key type\n",
 189                key_type_id_resolver.name);
 190
 191        cred = prepare_kernel_cred(NULL);
 192        if (!cred)
 193                return -ENOMEM;
 194
 195        keyring = key_alloc(&key_type_keyring, ".id_resolver", 0, 0, cred,
 196                             (KEY_POS_ALL & ~KEY_POS_SETATTR) |
 197                             KEY_USR_VIEW | KEY_USR_READ,
 198                             KEY_ALLOC_NOT_IN_QUOTA);
 199        if (IS_ERR(keyring)) {
 200                ret = PTR_ERR(keyring);
 201                goto failed_put_cred;
 202        }
 203
 204        ret = key_instantiate_and_link(keyring, NULL, 0, NULL, NULL);
 205        if (ret < 0)
 206                goto failed_put_key;
 207
 208        ret = register_key_type(&key_type_id_resolver);
 209        if (ret < 0)
 210                goto failed_put_key;
 211
 212        ret = register_key_type(&key_type_id_resolver_legacy);
 213        if (ret < 0)
 214                goto failed_reg_legacy;
 215
 216        set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
 217        cred->thread_keyring = keyring;
 218        cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
 219        id_resolver_cache = cred;
 220        return 0;
 221
 222failed_reg_legacy:
 223        unregister_key_type(&key_type_id_resolver);
 224failed_put_key:
 225        key_put(keyring);
 226failed_put_cred:
 227        put_cred(cred);
 228        return ret;
 229}
 230
 231static void nfs_idmap_quit_keyring(void)
 232{
 233        key_revoke(id_resolver_cache->thread_keyring);
 234        unregister_key_type(&key_type_id_resolver);
 235        unregister_key_type(&key_type_id_resolver_legacy);
 236        put_cred(id_resolver_cache);
 237}
 238
 239/*
 240 * Assemble the description to pass to request_key()
 241 * This function will allocate a new string and update dest to point
 242 * at it.  The caller is responsible for freeing dest.
 243 *
 244 * On error 0 is returned.  Otherwise, the length of dest is returned.
 245 */
 246static ssize_t nfs_idmap_get_desc(const char *name, size_t namelen,
 247                                const char *type, size_t typelen, char **desc)
 248{
 249        char *cp;
 250        size_t desclen = typelen + namelen + 2;
 251
 252        *desc = kmalloc(desclen, GFP_KERNEL);
 253        if (!*desc)
 254                return -ENOMEM;
 255
 256        cp = *desc;
 257        memcpy(cp, type, typelen);
 258        cp += typelen;
 259        *cp++ = ':';
 260
 261        memcpy(cp, name, namelen);
 262        cp += namelen;
 263        *cp = '\0';
 264        return desclen;
 265}
 266
 267static ssize_t nfs_idmap_request_key(struct key_type *key_type,
 268                                     const char *name, size_t namelen,
 269                                     const char *type, void *data,
 270                                     size_t data_size, struct idmap *idmap)
 271{
 272        const struct cred *saved_cred;
 273        struct key *rkey;
 274        char *desc;
 275        struct user_key_payload *payload;
 276        ssize_t ret;
 277
 278        ret = nfs_idmap_get_desc(name, namelen, type, strlen(type), &desc);
 279        if (ret <= 0)
 280                goto out;
 281
 282        saved_cred = override_creds(id_resolver_cache);
 283        if (idmap)
 284                rkey = request_key_with_auxdata(key_type, desc, "", 0, idmap);
 285        else
 286                rkey = request_key(&key_type_id_resolver, desc, "");
 287        revert_creds(saved_cred);
 288
 289        kfree(desc);
 290        if (IS_ERR(rkey)) {
 291                ret = PTR_ERR(rkey);
 292                goto out;
 293        }
 294
 295        rcu_read_lock();
 296        rkey->perm |= KEY_USR_VIEW;
 297
 298        ret = key_validate(rkey);
 299        if (ret < 0)
 300                goto out_up;
 301
 302        payload = rcu_dereference(rkey->payload.data);
 303        if (IS_ERR_OR_NULL(payload)) {
 304                ret = PTR_ERR(payload);
 305                goto out_up;
 306        }
 307
 308        ret = payload->datalen;
 309        if (ret > 0 && ret <= data_size)
 310                memcpy(data, payload->data, ret);
 311        else
 312                ret = -EINVAL;
 313
 314out_up:
 315        rcu_read_unlock();
 316        key_put(rkey);
 317out:
 318        return ret;
 319}
 320
 321static ssize_t nfs_idmap_get_key(const char *name, size_t namelen,
 322                                 const char *type, void *data,
 323                                 size_t data_size, struct idmap *idmap)
 324{
 325        ssize_t ret = nfs_idmap_request_key(&key_type_id_resolver,
 326                                            name, namelen, type, data,
 327                                            data_size, NULL);
 328        if (ret < 0) {
 329                mutex_lock(&idmap->idmap_mutex);
 330                ret = nfs_idmap_request_key(&key_type_id_resolver_legacy,
 331                                            name, namelen, type, data,
 332                                            data_size, idmap);
 333                idmap->idmap_key_cons = NULL;
 334                mutex_unlock(&idmap->idmap_mutex);
 335        }
 336        return ret;
 337}
 338
 339/* ID -> Name */
 340static ssize_t nfs_idmap_lookup_name(__u32 id, const char *type, char *buf,
 341                                     size_t buflen, struct idmap *idmap)
 342{
 343        char id_str[NFS_UINT_MAXLEN];
 344        int id_len;
 345        ssize_t ret;
 346
 347        id_len = snprintf(id_str, sizeof(id_str), "%u", id);
 348        ret = nfs_idmap_get_key(id_str, id_len, type, buf, buflen, idmap);
 349        if (ret < 0)
 350                return -EINVAL;
 351        return ret;
 352}
 353
 354/* Name -> ID */
 355static int nfs_idmap_lookup_id(const char *name, size_t namelen, const char *type,
 356                               __u32 *id, struct idmap *idmap)
 357{
 358        char id_str[NFS_UINT_MAXLEN];
 359        long id_long;
 360        ssize_t data_size;
 361        int ret = 0;
 362
 363        data_size = nfs_idmap_get_key(name, namelen, type, id_str, NFS_UINT_MAXLEN, idmap);
 364        if (data_size <= 0) {
 365                ret = -EINVAL;
 366        } else {
 367                ret = strict_strtol(id_str, 10, &id_long);
 368                *id = (__u32)id_long;
 369        }
 370        return ret;
 371}
 372
 373/* idmap classic begins here */
 374
 375enum {
 376        Opt_find_uid, Opt_find_gid, Opt_find_user, Opt_find_group, Opt_find_err
 377};
 378
 379static const match_table_t nfs_idmap_tokens = {
 380        { Opt_find_uid, "uid:%s" },
 381        { Opt_find_gid, "gid:%s" },
 382        { Opt_find_user, "user:%s" },
 383        { Opt_find_group, "group:%s" },
 384        { Opt_find_err, NULL }
 385};
 386
 387static int nfs_idmap_legacy_upcall(struct key_construction *, const char *, void *);
 388static ssize_t idmap_pipe_downcall(struct file *, const char __user *,
 389                                   size_t);
 390static void idmap_release_pipe(struct inode *);
 391static void idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
 392
 393static const struct rpc_pipe_ops idmap_upcall_ops = {
 394        .upcall         = rpc_pipe_generic_upcall,
 395        .downcall       = idmap_pipe_downcall,
 396        .release_pipe   = idmap_release_pipe,
 397        .destroy_msg    = idmap_pipe_destroy_msg,
 398};
 399
 400static struct key_type key_type_id_resolver_legacy = {
 401        .name           = "id_legacy",
 402        .instantiate    = user_instantiate,
 403        .match          = user_match,
 404        .revoke         = user_revoke,
 405        .destroy        = user_destroy,
 406        .describe       = user_describe,
 407        .read           = user_read,
 408        .request_key    = nfs_idmap_legacy_upcall,
 409};
 410
 411static void __nfs_idmap_unregister(struct rpc_pipe *pipe)
 412{
 413        if (pipe->dentry)
 414                rpc_unlink(pipe->dentry);
 415}
 416
 417static int __nfs_idmap_register(struct dentry *dir,
 418                                     struct idmap *idmap,
 419                                     struct rpc_pipe *pipe)
 420{
 421        struct dentry *dentry;
 422
 423        dentry = rpc_mkpipe_dentry(dir, "idmap", idmap, pipe);
 424        if (IS_ERR(dentry))
 425                return PTR_ERR(dentry);
 426        pipe->dentry = dentry;
 427        return 0;
 428}
 429
 430static void nfs_idmap_unregister(struct nfs_client *clp,
 431                                      struct rpc_pipe *pipe)
 432{
 433        struct net *net = clp->cl_net;
 434        struct super_block *pipefs_sb;
 435
 436        pipefs_sb = rpc_get_sb_net(net);
 437        if (pipefs_sb) {
 438                __nfs_idmap_unregister(pipe);
 439                rpc_put_sb_net(net);
 440        }
 441}
 442
 443static int nfs_idmap_register(struct nfs_client *clp,
 444                                   struct idmap *idmap,
 445                                   struct rpc_pipe *pipe)
 446{
 447        struct net *net = clp->cl_net;
 448        struct super_block *pipefs_sb;
 449        int err = 0;
 450
 451        pipefs_sb = rpc_get_sb_net(net);
 452        if (pipefs_sb) {
 453                if (clp->cl_rpcclient->cl_dentry)
 454                        err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
 455                                                   idmap, pipe);
 456                rpc_put_sb_net(net);
 457        }
 458        return err;
 459}
 460
 461int
 462nfs_idmap_new(struct nfs_client *clp)
 463{
 464        struct idmap *idmap;
 465        struct rpc_pipe *pipe;
 466        int error;
 467
 468        BUG_ON(clp->cl_idmap != NULL);
 469
 470        idmap = kzalloc(sizeof(*idmap), GFP_KERNEL);
 471        if (idmap == NULL)
 472                return -ENOMEM;
 473
 474        pipe = rpc_mkpipe_data(&idmap_upcall_ops, 0);
 475        if (IS_ERR(pipe)) {
 476                error = PTR_ERR(pipe);
 477                kfree(idmap);
 478                return error;
 479        }
 480        error = nfs_idmap_register(clp, idmap, pipe);
 481        if (error) {
 482                rpc_destroy_pipe_data(pipe);
 483                kfree(idmap);
 484                return error;
 485        }
 486        idmap->idmap_pipe = pipe;
 487        mutex_init(&idmap->idmap_mutex);
 488
 489        clp->cl_idmap = idmap;
 490        return 0;
 491}
 492
 493void
 494nfs_idmap_delete(struct nfs_client *clp)
 495{
 496        struct idmap *idmap = clp->cl_idmap;
 497
 498        if (!idmap)
 499                return;
 500        nfs_idmap_unregister(clp, idmap->idmap_pipe);
 501        rpc_destroy_pipe_data(idmap->idmap_pipe);
 502        clp->cl_idmap = NULL;
 503        kfree(idmap);
 504}
 505
 506static int __rpc_pipefs_event(struct nfs_client *clp, unsigned long event,
 507                              struct super_block *sb)
 508{
 509        int err = 0;
 510
 511        switch (event) {
 512        case RPC_PIPEFS_MOUNT:
 513                BUG_ON(clp->cl_rpcclient->cl_dentry == NULL);
 514                err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
 515                                                clp->cl_idmap,
 516                                                clp->cl_idmap->idmap_pipe);
 517                break;
 518        case RPC_PIPEFS_UMOUNT:
 519                if (clp->cl_idmap->idmap_pipe) {
 520                        struct dentry *parent;
 521
 522                        parent = clp->cl_idmap->idmap_pipe->dentry->d_parent;
 523                        __nfs_idmap_unregister(clp->cl_idmap->idmap_pipe);
 524                        /*
 525                         * Note: This is a dirty hack. SUNRPC hook has been
 526                         * called already but simple_rmdir() call for the
 527                         * directory returned with error because of idmap pipe
 528                         * inside. Thus now we have to remove this directory
 529                         * here.
 530                         */
 531                        if (rpc_rmdir(parent))
 532                                printk(KERN_ERR "NFS: %s: failed to remove "
 533                                        "clnt dir!\n", __func__);
 534                }
 535                break;
 536        default:
 537                printk(KERN_ERR "NFS: %s: unknown event: %ld\n", __func__,
 538                        event);
 539                return -ENOTSUPP;
 540        }
 541        return err;
 542}
 543
 544static struct nfs_client *nfs_get_client_for_event(struct net *net, int event)
 545{
 546        struct nfs_net *nn = net_generic(net, nfs_net_id);
 547        struct dentry *cl_dentry;
 548        struct nfs_client *clp;
 549        int err;
 550
 551restart:
 552        spin_lock(&nn->nfs_client_lock);
 553        list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
 554                /* Wait for initialisation to finish */
 555                if (clp->cl_cons_state == NFS_CS_INITING) {
 556                        atomic_inc(&clp->cl_count);
 557                        spin_unlock(&nn->nfs_client_lock);
 558                        err = nfs_wait_client_init_complete(clp);
 559                        nfs_put_client(clp);
 560                        if (err)
 561                                return NULL;
 562                        goto restart;
 563                }
 564                /* Skip nfs_clients that failed to initialise */
 565                if (clp->cl_cons_state < 0)
 566                        continue;
 567                smp_rmb();
 568                if (clp->rpc_ops != &nfs_v4_clientops)
 569                        continue;
 570                cl_dentry = clp->cl_idmap->idmap_pipe->dentry;
 571                if (((event == RPC_PIPEFS_MOUNT) && cl_dentry) ||
 572                    ((event == RPC_PIPEFS_UMOUNT) && !cl_dentry))
 573                        continue;
 574                atomic_inc(&clp->cl_count);
 575                spin_unlock(&nn->nfs_client_lock);
 576                return clp;
 577        }
 578        spin_unlock(&nn->nfs_client_lock);
 579        return NULL;
 580}
 581
 582static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
 583                            void *ptr)
 584{
 585        struct super_block *sb = ptr;
 586        struct nfs_client *clp;
 587        int error = 0;
 588
 589        if (!try_module_get(THIS_MODULE))
 590                return 0;
 591
 592        while ((clp = nfs_get_client_for_event(sb->s_fs_info, event))) {
 593                error = __rpc_pipefs_event(clp, event, sb);
 594                nfs_put_client(clp);
 595                if (error)
 596                        break;
 597        }
 598        module_put(THIS_MODULE);
 599        return error;
 600}
 601
 602#define PIPEFS_NFS_PRIO         1
 603
 604static struct notifier_block nfs_idmap_block = {
 605        .notifier_call  = rpc_pipefs_event,
 606        .priority       = SUNRPC_PIPEFS_NFS_PRIO,
 607};
 608
 609int nfs_idmap_init(void)
 610{
 611        int ret;
 612        ret = nfs_idmap_init_keyring();
 613        if (ret != 0)
 614                goto out;
 615        ret = rpc_pipefs_notifier_register(&nfs_idmap_block);
 616        if (ret != 0)
 617                nfs_idmap_quit_keyring();
 618out:
 619        return ret;
 620}
 621
 622void nfs_idmap_quit(void)
 623{
 624        rpc_pipefs_notifier_unregister(&nfs_idmap_block);
 625        nfs_idmap_quit_keyring();
 626}
 627
 628static int nfs_idmap_prepare_message(char *desc, struct idmap *idmap,
 629                                     struct idmap_msg *im,
 630                                     struct rpc_pipe_msg *msg)
 631{
 632        substring_t substr;
 633        int token, ret;
 634
 635        memset(im,  0, sizeof(*im));
 636        memset(msg, 0, sizeof(*msg));
 637
 638        im->im_type = IDMAP_TYPE_GROUP;
 639        token = match_token(desc, nfs_idmap_tokens, &substr);
 640
 641        switch (token) {
 642        case Opt_find_uid:
 643                im->im_type = IDMAP_TYPE_USER;
 644        case Opt_find_gid:
 645                im->im_conv = IDMAP_CONV_NAMETOID;
 646                ret = match_strlcpy(im->im_name, &substr, IDMAP_NAMESZ);
 647                break;
 648
 649        case Opt_find_user:
 650                im->im_type = IDMAP_TYPE_USER;
 651        case Opt_find_group:
 652                im->im_conv = IDMAP_CONV_IDTONAME;
 653                ret = match_int(&substr, &im->im_id);
 654                break;
 655
 656        default:
 657                ret = -EINVAL;
 658                goto out;
 659        }
 660
 661        msg->data = im;
 662        msg->len  = sizeof(struct idmap_msg);
 663
 664out:
 665        return ret;
 666}
 667
 668static int nfs_idmap_legacy_upcall(struct key_construction *cons,
 669                                   const char *op,
 670                                   void *aux)
 671{
 672        struct idmap_legacy_upcalldata *data;
 673        struct rpc_pipe_msg *msg;
 674        struct idmap_msg *im;
 675        struct idmap *idmap = (struct idmap *)aux;
 676        struct key *key = cons->key;
 677        int ret = -ENOMEM;
 678
 679        /* msg and im are freed in idmap_pipe_destroy_msg */
 680        data = kmalloc(sizeof(*data), GFP_KERNEL);
 681        if (!data)
 682                goto out1;
 683
 684        msg = &data->pipe_msg;
 685        im = &data->idmap_msg;
 686        data->idmap = idmap;
 687
 688        ret = nfs_idmap_prepare_message(key->description, idmap, im, msg);
 689        if (ret < 0)
 690                goto out2;
 691
 692        BUG_ON(idmap->idmap_key_cons != NULL);
 693        idmap->idmap_key_cons = cons;
 694
 695        ret = rpc_queue_upcall(idmap->idmap_pipe, msg);
 696        if (ret < 0)
 697                goto out3;
 698
 699        return ret;
 700
 701out3:
 702        idmap->idmap_key_cons = NULL;
 703out2:
 704        kfree(data);
 705out1:
 706        complete_request_key(cons, ret);
 707        return ret;
 708}
 709
 710static int nfs_idmap_instantiate(struct key *key, struct key *authkey, char *data)
 711{
 712        return key_instantiate_and_link(key, data, strlen(data) + 1,
 713                                        id_resolver_cache->thread_keyring,
 714                                        authkey);
 715}
 716
 717static int nfs_idmap_read_message(struct idmap_msg *im, struct key *key, struct key *authkey)
 718{
 719        char id_str[NFS_UINT_MAXLEN];
 720        int ret = -EINVAL;
 721
 722        switch (im->im_conv) {
 723        case IDMAP_CONV_NAMETOID:
 724                sprintf(id_str, "%d", im->im_id);
 725                ret = nfs_idmap_instantiate(key, authkey, id_str);
 726                break;
 727        case IDMAP_CONV_IDTONAME:
 728                ret = nfs_idmap_instantiate(key, authkey, im->im_name);
 729                break;
 730        }
 731
 732        return ret;
 733}
 734
 735static ssize_t
 736idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
 737{
 738        struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
 739        struct idmap *idmap = (struct idmap *)rpci->private;
 740        struct key_construction *cons;
 741        struct idmap_msg im;
 742        size_t namelen_in;
 743        int ret;
 744
 745        /* If instantiation is successful, anyone waiting for key construction
 746         * will have been woken up and someone else may now have used
 747         * idmap_key_cons - so after this point we may no longer touch it.
 748         */
 749        cons = ACCESS_ONCE(idmap->idmap_key_cons);
 750        idmap->idmap_key_cons = NULL;
 751
 752        if (mlen != sizeof(im)) {
 753                ret = -ENOSPC;
 754                goto out;
 755        }
 756
 757        if (copy_from_user(&im, src, mlen) != 0) {
 758                ret = -EFAULT;
 759                goto out;
 760        }
 761
 762        if (!(im.im_status & IDMAP_STATUS_SUCCESS)) {
 763                ret = -ENOKEY;
 764                goto out;
 765        }
 766
 767        namelen_in = strnlen(im.im_name, IDMAP_NAMESZ);
 768        if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ) {
 769                ret = -EINVAL;
 770                goto out;
 771        }
 772
 773        ret = nfs_idmap_read_message(&im, cons->key, cons->authkey);
 774        if (ret >= 0) {
 775                key_set_timeout(cons->key, nfs_idmap_cache_timeout);
 776                ret = mlen;
 777        }
 778
 779out:
 780        complete_request_key(cons, ret);
 781        return ret;
 782}
 783
 784static void
 785idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
 786{
 787        struct idmap_legacy_upcalldata *data = container_of(msg,
 788                        struct idmap_legacy_upcalldata,
 789                        pipe_msg);
 790        struct idmap *idmap = data->idmap;
 791        struct key_construction *cons;
 792        if (msg->errno) {
 793                cons = ACCESS_ONCE(idmap->idmap_key_cons);
 794                idmap->idmap_key_cons = NULL;
 795                complete_request_key(cons, msg->errno);
 796        }
 797        /* Free memory allocated in nfs_idmap_legacy_upcall() */
 798        kfree(data);
 799}
 800
 801static void
 802idmap_release_pipe(struct inode *inode)
 803{
 804        struct rpc_inode *rpci = RPC_I(inode);
 805        struct idmap *idmap = (struct idmap *)rpci->private;
 806        idmap->idmap_key_cons = NULL;
 807}
 808
 809int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, __u32 *uid)
 810{
 811        struct idmap *idmap = server->nfs_client->cl_idmap;
 812
 813        if (nfs_map_string_to_numeric(name, namelen, uid))
 814                return 0;
 815        return nfs_idmap_lookup_id(name, namelen, "uid", uid, idmap);
 816}
 817
 818int nfs_map_group_to_gid(const struct nfs_server *server, const char *name, size_t namelen, __u32 *gid)
 819{
 820        struct idmap *idmap = server->nfs_client->cl_idmap;
 821
 822        if (nfs_map_string_to_numeric(name, namelen, gid))
 823                return 0;
 824        return nfs_idmap_lookup_id(name, namelen, "gid", gid, idmap);
 825}
 826
 827int nfs_map_uid_to_name(const struct nfs_server *server, __u32 uid, char *buf, size_t buflen)
 828{
 829        struct idmap *idmap = server->nfs_client->cl_idmap;
 830        int ret = -EINVAL;
 831
 832        if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
 833                ret = nfs_idmap_lookup_name(uid, "user", buf, buflen, idmap);
 834        if (ret < 0)
 835                ret = nfs_map_numeric_to_string(uid, buf, buflen);
 836        return ret;
 837}
 838int nfs_map_gid_to_group(const struct nfs_server *server, __u32 gid, char *buf, size_t buflen)
 839{
 840        struct idmap *idmap = server->nfs_client->cl_idmap;
 841        int ret = -EINVAL;
 842
 843        if (!(server->caps & NFS_CAP_UIDGID_NOMAP))
 844                ret = nfs_idmap_lookup_name(gid, "group", buf, buflen, idmap);
 845        if (ret < 0)
 846                ret = nfs_map_numeric_to_string(gid, buf, buflen);
 847        return ret;
 848}
 849
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