linux/fs/nfsd/nfs4idmap.c
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   1/*
   2 *  Mapping of UID/GIDs to name and vice versa.
   3 *
   4 *  Copyright (c) 2002, 2003 The Regents of the University of
   5 *  Michigan.  All rights reserved.
   6 *
   7 *  Marius Aamodt Eriksen <marius@umich.edu>
   8 *
   9 *  Redistribution and use in source and binary forms, with or without
  10 *  modification, are permitted provided that the following conditions
  11 *  are met:
  12 *
  13 *  1. Redistributions of source code must retain the above copyright
  14 *     notice, this list of conditions and the following disclaimer.
  15 *  2. Redistributions in binary form must reproduce the above copyright
  16 *     notice, this list of conditions and the following disclaimer in the
  17 *     documentation and/or other materials provided with the distribution.
  18 *  3. Neither the name of the University nor the names of its
  19 *     contributors may be used to endorse or promote products derived
  20 *     from this software without specific prior written permission.
  21 *
  22 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  23 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  24 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  25 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  27 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  28 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  29 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  30 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  31 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  32 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  33 */
  34
  35#include <linux/module.h>
  36#include <linux/seq_file.h>
  37#include <linux/sched.h>
  38#include <linux/slab.h>
  39#include <linux/sunrpc/svc_xprt.h>
  40#include <net/net_namespace.h>
  41#include "idmap.h"
  42#include "nfsd.h"
  43#include "netns.h"
  44
  45/*
  46 * Turn off idmapping when using AUTH_SYS.
  47 */
  48static bool nfs4_disable_idmapping = true;
  49module_param(nfs4_disable_idmapping, bool, 0644);
  50MODULE_PARM_DESC(nfs4_disable_idmapping,
  51                "Turn off server's NFSv4 idmapping when using 'sec=sys'");
  52
  53/*
  54 * Cache entry
  55 */
  56
  57/*
  58 * XXX we know that IDMAP_NAMESZ < PAGE_SIZE, but it's ugly to rely on
  59 * that.
  60 */
  61
  62#define IDMAP_TYPE_USER  0
  63#define IDMAP_TYPE_GROUP 1
  64
  65struct ent {
  66        struct cache_head h;
  67        int               type;                /* User / Group */
  68        uid_t             id;
  69        char              name[IDMAP_NAMESZ];
  70        char              authname[IDMAP_NAMESZ];
  71};
  72
  73/* Common entry handling */
  74
  75#define ENT_HASHBITS          8
  76#define ENT_HASHMAX           (1 << ENT_HASHBITS)
  77
  78static void
  79ent_init(struct cache_head *cnew, struct cache_head *citm)
  80{
  81        struct ent *new = container_of(cnew, struct ent, h);
  82        struct ent *itm = container_of(citm, struct ent, h);
  83
  84        new->id = itm->id;
  85        new->type = itm->type;
  86
  87        strlcpy(new->name, itm->name, sizeof(new->name));
  88        strlcpy(new->authname, itm->authname, sizeof(new->name));
  89}
  90
  91static void
  92ent_put(struct kref *ref)
  93{
  94        struct ent *map = container_of(ref, struct ent, h.ref);
  95        kfree(map);
  96}
  97
  98static struct cache_head *
  99ent_alloc(void)
 100{
 101        struct ent *e = kmalloc(sizeof(*e), GFP_KERNEL);
 102        if (e)
 103                return &e->h;
 104        else
 105                return NULL;
 106}
 107
 108/*
 109 * ID -> Name cache
 110 */
 111
 112static uint32_t
 113idtoname_hash(struct ent *ent)
 114{
 115        uint32_t hash;
 116
 117        hash = hash_str(ent->authname, ENT_HASHBITS);
 118        hash = hash_long(hash ^ ent->id, ENT_HASHBITS);
 119
 120        /* Flip LSB for user/group */
 121        if (ent->type == IDMAP_TYPE_GROUP)
 122                hash ^= 1;
 123
 124        return hash;
 125}
 126
 127static void
 128idtoname_request(struct cache_detail *cd, struct cache_head *ch, char **bpp,
 129    int *blen)
 130{
 131        struct ent *ent = container_of(ch, struct ent, h);
 132        char idstr[11];
 133
 134        qword_add(bpp, blen, ent->authname);
 135        snprintf(idstr, sizeof(idstr), "%u", ent->id);
 136        qword_add(bpp, blen, ent->type == IDMAP_TYPE_GROUP ? "group" : "user");
 137        qword_add(bpp, blen, idstr);
 138
 139        (*bpp)[-1] = '\n';
 140}
 141
 142static int
 143idtoname_upcall(struct cache_detail *cd, struct cache_head *ch)
 144{
 145        return sunrpc_cache_pipe_upcall(cd, ch, idtoname_request);
 146}
 147
 148static int
 149idtoname_match(struct cache_head *ca, struct cache_head *cb)
 150{
 151        struct ent *a = container_of(ca, struct ent, h);
 152        struct ent *b = container_of(cb, struct ent, h);
 153
 154        return (a->id == b->id && a->type == b->type &&
 155            strcmp(a->authname, b->authname) == 0);
 156}
 157
 158static int
 159idtoname_show(struct seq_file *m, struct cache_detail *cd, struct cache_head *h)
 160{
 161        struct ent *ent;
 162
 163        if (h == NULL) {
 164                seq_puts(m, "#domain type id [name]\n");
 165                return 0;
 166        }
 167        ent = container_of(h, struct ent, h);
 168        seq_printf(m, "%s %s %u", ent->authname,
 169                        ent->type == IDMAP_TYPE_GROUP ? "group" : "user",
 170                        ent->id);
 171        if (test_bit(CACHE_VALID, &h->flags))
 172                seq_printf(m, " %s", ent->name);
 173        seq_printf(m, "\n");
 174        return 0;
 175}
 176
 177static void
 178warn_no_idmapd(struct cache_detail *detail, int has_died)
 179{
 180        printk("nfsd: nfsv4 idmapping failing: has idmapd %s?\n",
 181                        has_died ? "died" : "not been started");
 182}
 183
 184
 185static int         idtoname_parse(struct cache_detail *, char *, int);
 186static struct ent *idtoname_lookup(struct cache_detail *, struct ent *);
 187static struct ent *idtoname_update(struct cache_detail *, struct ent *,
 188                                   struct ent *);
 189
 190static struct cache_detail idtoname_cache_template = {
 191        .owner          = THIS_MODULE,
 192        .hash_size      = ENT_HASHMAX,
 193        .name           = "nfs4.idtoname",
 194        .cache_put      = ent_put,
 195        .cache_upcall   = idtoname_upcall,
 196        .cache_parse    = idtoname_parse,
 197        .cache_show     = idtoname_show,
 198        .warn_no_listener = warn_no_idmapd,
 199        .match          = idtoname_match,
 200        .init           = ent_init,
 201        .update         = ent_init,
 202        .alloc          = ent_alloc,
 203};
 204
 205static int
 206idtoname_parse(struct cache_detail *cd, char *buf, int buflen)
 207{
 208        struct ent ent, *res;
 209        char *buf1, *bp;
 210        int len;
 211        int error = -EINVAL;
 212
 213        if (buf[buflen - 1] != '\n')
 214                return (-EINVAL);
 215        buf[buflen - 1]= '\0';
 216
 217        buf1 = kmalloc(PAGE_SIZE, GFP_KERNEL);
 218        if (buf1 == NULL)
 219                return (-ENOMEM);
 220
 221        memset(&ent, 0, sizeof(ent));
 222
 223        /* Authentication name */
 224        if (qword_get(&buf, buf1, PAGE_SIZE) <= 0)
 225                goto out;
 226        memcpy(ent.authname, buf1, sizeof(ent.authname));
 227
 228        /* Type */
 229        if (qword_get(&buf, buf1, PAGE_SIZE) <= 0)
 230                goto out;
 231        ent.type = strcmp(buf1, "user") == 0 ?
 232                IDMAP_TYPE_USER : IDMAP_TYPE_GROUP;
 233
 234        /* ID */
 235        if (qword_get(&buf, buf1, PAGE_SIZE) <= 0)
 236                goto out;
 237        ent.id = simple_strtoul(buf1, &bp, 10);
 238        if (bp == buf1)
 239                goto out;
 240
 241        /* expiry */
 242        ent.h.expiry_time = get_expiry(&buf);
 243        if (ent.h.expiry_time == 0)
 244                goto out;
 245
 246        error = -ENOMEM;
 247        res = idtoname_lookup(cd, &ent);
 248        if (!res)
 249                goto out;
 250
 251        /* Name */
 252        error = -EINVAL;
 253        len = qword_get(&buf, buf1, PAGE_SIZE);
 254        if (len < 0)
 255                goto out;
 256        if (len == 0)
 257                set_bit(CACHE_NEGATIVE, &ent.h.flags);
 258        else if (len >= IDMAP_NAMESZ)
 259                goto out;
 260        else
 261                memcpy(ent.name, buf1, sizeof(ent.name));
 262        error = -ENOMEM;
 263        res = idtoname_update(cd, &ent, res);
 264        if (res == NULL)
 265                goto out;
 266
 267        cache_put(&res->h, cd);
 268
 269        error = 0;
 270out:
 271        kfree(buf1);
 272
 273        return error;
 274}
 275
 276
 277static struct ent *
 278idtoname_lookup(struct cache_detail *cd, struct ent *item)
 279{
 280        struct cache_head *ch = sunrpc_cache_lookup(cd, &item->h,
 281                                                    idtoname_hash(item));
 282        if (ch)
 283                return container_of(ch, struct ent, h);
 284        else
 285                return NULL;
 286}
 287
 288static struct ent *
 289idtoname_update(struct cache_detail *cd, struct ent *new, struct ent *old)
 290{
 291        struct cache_head *ch = sunrpc_cache_update(cd, &new->h, &old->h,
 292                                                    idtoname_hash(new));
 293        if (ch)
 294                return container_of(ch, struct ent, h);
 295        else
 296                return NULL;
 297}
 298
 299
 300/*
 301 * Name -> ID cache
 302 */
 303
 304static inline int
 305nametoid_hash(struct ent *ent)
 306{
 307        return hash_str(ent->name, ENT_HASHBITS);
 308}
 309
 310static void
 311nametoid_request(struct cache_detail *cd, struct cache_head *ch, char **bpp,
 312    int *blen)
 313{
 314        struct ent *ent = container_of(ch, struct ent, h);
 315
 316        qword_add(bpp, blen, ent->authname);
 317        qword_add(bpp, blen, ent->type == IDMAP_TYPE_GROUP ? "group" : "user");
 318        qword_add(bpp, blen, ent->name);
 319
 320        (*bpp)[-1] = '\n';
 321}
 322
 323static int
 324nametoid_upcall(struct cache_detail *cd, struct cache_head *ch)
 325{
 326        return sunrpc_cache_pipe_upcall(cd, ch, nametoid_request);
 327}
 328
 329static int
 330nametoid_match(struct cache_head *ca, struct cache_head *cb)
 331{
 332        struct ent *a = container_of(ca, struct ent, h);
 333        struct ent *b = container_of(cb, struct ent, h);
 334
 335        return (a->type == b->type && strcmp(a->name, b->name) == 0 &&
 336            strcmp(a->authname, b->authname) == 0);
 337}
 338
 339static int
 340nametoid_show(struct seq_file *m, struct cache_detail *cd, struct cache_head *h)
 341{
 342        struct ent *ent;
 343
 344        if (h == NULL) {
 345                seq_puts(m, "#domain type name [id]\n");
 346                return 0;
 347        }
 348        ent = container_of(h, struct ent, h);
 349        seq_printf(m, "%s %s %s", ent->authname,
 350                        ent->type == IDMAP_TYPE_GROUP ? "group" : "user",
 351                        ent->name);
 352        if (test_bit(CACHE_VALID, &h->flags))
 353                seq_printf(m, " %u", ent->id);
 354        seq_printf(m, "\n");
 355        return 0;
 356}
 357
 358static struct ent *nametoid_lookup(struct cache_detail *, struct ent *);
 359static struct ent *nametoid_update(struct cache_detail *, struct ent *,
 360                                   struct ent *);
 361static int         nametoid_parse(struct cache_detail *, char *, int);
 362
 363static struct cache_detail nametoid_cache_template = {
 364        .owner          = THIS_MODULE,
 365        .hash_size      = ENT_HASHMAX,
 366        .name           = "nfs4.nametoid",
 367        .cache_put      = ent_put,
 368        .cache_upcall   = nametoid_upcall,
 369        .cache_parse    = nametoid_parse,
 370        .cache_show     = nametoid_show,
 371        .warn_no_listener = warn_no_idmapd,
 372        .match          = nametoid_match,
 373        .init           = ent_init,
 374        .update         = ent_init,
 375        .alloc          = ent_alloc,
 376};
 377
 378static int
 379nametoid_parse(struct cache_detail *cd, char *buf, int buflen)
 380{
 381        struct ent ent, *res;
 382        char *buf1;
 383        int error = -EINVAL;
 384
 385        if (buf[buflen - 1] != '\n')
 386                return (-EINVAL);
 387        buf[buflen - 1]= '\0';
 388
 389        buf1 = kmalloc(PAGE_SIZE, GFP_KERNEL);
 390        if (buf1 == NULL)
 391                return (-ENOMEM);
 392
 393        memset(&ent, 0, sizeof(ent));
 394
 395        /* Authentication name */
 396        if (qword_get(&buf, buf1, PAGE_SIZE) <= 0)
 397                goto out;
 398        memcpy(ent.authname, buf1, sizeof(ent.authname));
 399
 400        /* Type */
 401        if (qword_get(&buf, buf1, PAGE_SIZE) <= 0)
 402                goto out;
 403        ent.type = strcmp(buf1, "user") == 0 ?
 404                IDMAP_TYPE_USER : IDMAP_TYPE_GROUP;
 405
 406        /* Name */
 407        error = qword_get(&buf, buf1, PAGE_SIZE);
 408        if (error <= 0 || error >= IDMAP_NAMESZ)
 409                goto out;
 410        memcpy(ent.name, buf1, sizeof(ent.name));
 411
 412        /* expiry */
 413        ent.h.expiry_time = get_expiry(&buf);
 414        if (ent.h.expiry_time == 0)
 415                goto out;
 416
 417        /* ID */
 418        error = get_int(&buf, &ent.id);
 419        if (error == -EINVAL)
 420                goto out;
 421        if (error == -ENOENT)
 422                set_bit(CACHE_NEGATIVE, &ent.h.flags);
 423
 424        error = -ENOMEM;
 425        res = nametoid_lookup(cd, &ent);
 426        if (res == NULL)
 427                goto out;
 428        res = nametoid_update(cd, &ent, res);
 429        if (res == NULL)
 430                goto out;
 431
 432        cache_put(&res->h, cd);
 433        error = 0;
 434out:
 435        kfree(buf1);
 436
 437        return (error);
 438}
 439
 440
 441static struct ent *
 442nametoid_lookup(struct cache_detail *cd, struct ent *item)
 443{
 444        struct cache_head *ch = sunrpc_cache_lookup(cd, &item->h,
 445                                                    nametoid_hash(item));
 446        if (ch)
 447                return container_of(ch, struct ent, h);
 448        else
 449                return NULL;
 450}
 451
 452static struct ent *
 453nametoid_update(struct cache_detail *cd, struct ent *new, struct ent *old)
 454{
 455        struct cache_head *ch = sunrpc_cache_update(cd, &new->h, &old->h,
 456                                                    nametoid_hash(new));
 457        if (ch)
 458                return container_of(ch, struct ent, h);
 459        else
 460                return NULL;
 461}
 462
 463/*
 464 * Exported API
 465 */
 466
 467int
 468nfsd_idmap_init(struct net *net)
 469{
 470        int rv;
 471        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 472
 473        nn->idtoname_cache = cache_create_net(&idtoname_cache_template, net);
 474        if (IS_ERR(nn->idtoname_cache))
 475                return PTR_ERR(nn->idtoname_cache);
 476        rv = cache_register_net(nn->idtoname_cache, net);
 477        if (rv)
 478                goto destroy_idtoname_cache;
 479        nn->nametoid_cache = cache_create_net(&nametoid_cache_template, net);
 480        if (IS_ERR(nn->nametoid_cache)) {
 481                rv = PTR_ERR(nn->idtoname_cache);
 482                goto unregister_idtoname_cache;
 483        }
 484        rv = cache_register_net(nn->nametoid_cache, net);
 485        if (rv)
 486                goto destroy_nametoid_cache;
 487        return 0;
 488
 489destroy_nametoid_cache:
 490        cache_destroy_net(nn->nametoid_cache, net);
 491unregister_idtoname_cache:
 492        cache_unregister_net(nn->idtoname_cache, net);
 493destroy_idtoname_cache:
 494        cache_destroy_net(nn->idtoname_cache, net);
 495        return rv;
 496}
 497
 498void
 499nfsd_idmap_shutdown(struct net *net)
 500{
 501        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 502
 503        cache_unregister_net(nn->idtoname_cache, net);
 504        cache_unregister_net(nn->nametoid_cache, net);
 505        cache_destroy_net(nn->idtoname_cache, net);
 506        cache_destroy_net(nn->nametoid_cache, net);
 507}
 508
 509static int
 510idmap_lookup(struct svc_rqst *rqstp,
 511                struct ent *(*lookup_fn)(struct cache_detail *, struct ent *),
 512                struct ent *key, struct cache_detail *detail, struct ent **item)
 513{
 514        int ret;
 515
 516        *item = lookup_fn(detail, key);
 517        if (!*item)
 518                return -ENOMEM;
 519 retry:
 520        ret = cache_check(detail, &(*item)->h, &rqstp->rq_chandle);
 521
 522        if (ret == -ETIMEDOUT) {
 523                struct ent *prev_item = *item;
 524                *item = lookup_fn(detail, key);
 525                if (*item != prev_item)
 526                        goto retry;
 527                cache_put(&(*item)->h, detail);
 528        }
 529        return ret;
 530}
 531
 532static char *
 533rqst_authname(struct svc_rqst *rqstp)
 534{
 535        struct auth_domain *clp;
 536
 537        clp = rqstp->rq_gssclient ? rqstp->rq_gssclient : rqstp->rq_client;
 538        return clp->name;
 539}
 540
 541static __be32
 542idmap_name_to_id(struct svc_rqst *rqstp, int type, const char *name, u32 namelen,
 543                uid_t *id)
 544{
 545        struct ent *item, key = {
 546                .type = type,
 547        };
 548        int ret;
 549        struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
 550
 551        if (namelen + 1 > sizeof(key.name))
 552                return nfserr_badowner;
 553        memcpy(key.name, name, namelen);
 554        key.name[namelen] = '\0';
 555        strlcpy(key.authname, rqst_authname(rqstp), sizeof(key.authname));
 556        ret = idmap_lookup(rqstp, nametoid_lookup, &key, nn->nametoid_cache, &item);
 557        if (ret == -ENOENT)
 558                return nfserr_badowner;
 559        if (ret)
 560                return nfserrno(ret);
 561        *id = item->id;
 562        cache_put(&item->h, nn->nametoid_cache);
 563        return 0;
 564}
 565
 566static int
 567idmap_id_to_name(struct svc_rqst *rqstp, int type, uid_t id, char *name)
 568{
 569        struct ent *item, key = {
 570                .id = id,
 571                .type = type,
 572        };
 573        int ret;
 574        struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
 575
 576        strlcpy(key.authname, rqst_authname(rqstp), sizeof(key.authname));
 577        ret = idmap_lookup(rqstp, idtoname_lookup, &key, nn->idtoname_cache, &item);
 578        if (ret == -ENOENT)
 579                return sprintf(name, "%u", id);
 580        if (ret)
 581                return ret;
 582        ret = strlen(item->name);
 583        BUG_ON(ret > IDMAP_NAMESZ);
 584        memcpy(name, item->name, ret);
 585        cache_put(&item->h, nn->idtoname_cache);
 586        return ret;
 587}
 588
 589static bool
 590numeric_name_to_id(struct svc_rqst *rqstp, int type, const char *name, u32 namelen, uid_t *id)
 591{
 592        int ret;
 593        char buf[11];
 594
 595        if (namelen + 1 > sizeof(buf))
 596                /* too long to represent a 32-bit id: */
 597                return false;
 598        /* Just to make sure it's null-terminated: */
 599        memcpy(buf, name, namelen);
 600        buf[namelen] = '\0';
 601        ret = kstrtouint(name, 10, id);
 602        return ret == 0;
 603}
 604
 605static __be32
 606do_name_to_id(struct svc_rqst *rqstp, int type, const char *name, u32 namelen, uid_t *id)
 607{
 608        if (nfs4_disable_idmapping && rqstp->rq_cred.cr_flavor < RPC_AUTH_GSS)
 609                if (numeric_name_to_id(rqstp, type, name, namelen, id))
 610                        return 0;
 611                /*
 612                 * otherwise, fall through and try idmapping, for
 613                 * backwards compatibility with clients sending names:
 614                 */
 615        return idmap_name_to_id(rqstp, type, name, namelen, id);
 616}
 617
 618static int
 619do_id_to_name(struct svc_rqst *rqstp, int type, uid_t id, char *name)
 620{
 621        if (nfs4_disable_idmapping && rqstp->rq_cred.cr_flavor < RPC_AUTH_GSS)
 622                return sprintf(name, "%u", id);
 623        return idmap_id_to_name(rqstp, type, id, name);
 624}
 625
 626__be32
 627nfsd_map_name_to_uid(struct svc_rqst *rqstp, const char *name, size_t namelen,
 628                __u32 *id)
 629{
 630        return do_name_to_id(rqstp, IDMAP_TYPE_USER, name, namelen, id);
 631}
 632
 633__be32
 634nfsd_map_name_to_gid(struct svc_rqst *rqstp, const char *name, size_t namelen,
 635                __u32 *id)
 636{
 637        return do_name_to_id(rqstp, IDMAP_TYPE_GROUP, name, namelen, id);
 638}
 639
 640int
 641nfsd_map_uid_to_name(struct svc_rqst *rqstp, __u32 id, char *name)
 642{
 643        return do_id_to_name(rqstp, IDMAP_TYPE_USER, id, name);
 644}
 645
 646int
 647nfsd_map_gid_to_name(struct svc_rqst *rqstp, __u32 id, char *name)
 648{
 649        return do_id_to_name(rqstp, IDMAP_TYPE_GROUP, id, name);
 650}
 651
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