linux/fs/nfsd/nfs4acl.c
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   1/*
   2 *  Common NFSv4 ACL handling code.
   3 *
   4 *  Copyright (c) 2002, 2003 The Regents of the University of Michigan.
   5 *  All rights reserved.
   6 *
   7 *  Marius Aamodt Eriksen <marius@umich.edu>
   8 *  Jeff Sedlak <jsedlak@umich.edu>
   9 *  J. Bruce Fields <bfields@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
  37#include <linux/slab.h>
  38#include <linux/nfs_fs.h>
  39#include <linux/export.h>
  40#include "acl.h"
  41
  42
  43/* mode bit translations: */
  44#define NFS4_READ_MODE (NFS4_ACE_READ_DATA)
  45#define NFS4_WRITE_MODE (NFS4_ACE_WRITE_DATA | NFS4_ACE_APPEND_DATA)
  46#define NFS4_EXECUTE_MODE NFS4_ACE_EXECUTE
  47#define NFS4_ANYONE_MODE (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL | NFS4_ACE_SYNCHRONIZE)
  48#define NFS4_OWNER_MODE (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL)
  49
  50/* We don't support these bits; insist they be neither allowed nor denied */
  51#define NFS4_MASK_UNSUPP (NFS4_ACE_DELETE | NFS4_ACE_WRITE_OWNER \
  52                | NFS4_ACE_READ_NAMED_ATTRS | NFS4_ACE_WRITE_NAMED_ATTRS)
  53
  54/* flags used to simulate posix default ACLs */
  55#define NFS4_INHERITANCE_FLAGS (NFS4_ACE_FILE_INHERIT_ACE \
  56                | NFS4_ACE_DIRECTORY_INHERIT_ACE)
  57
  58#define NFS4_SUPPORTED_FLAGS (NFS4_INHERITANCE_FLAGS \
  59                | NFS4_ACE_INHERIT_ONLY_ACE \
  60                | NFS4_ACE_IDENTIFIER_GROUP)
  61
  62#define MASK_EQUAL(mask1, mask2) \
  63        ( ((mask1) & NFS4_ACE_MASK_ALL) == ((mask2) & NFS4_ACE_MASK_ALL) )
  64
  65static u32
  66mask_from_posix(unsigned short perm, unsigned int flags)
  67{
  68        int mask = NFS4_ANYONE_MODE;
  69
  70        if (flags & NFS4_ACL_OWNER)
  71                mask |= NFS4_OWNER_MODE;
  72        if (perm & ACL_READ)
  73                mask |= NFS4_READ_MODE;
  74        if (perm & ACL_WRITE)
  75                mask |= NFS4_WRITE_MODE;
  76        if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
  77                mask |= NFS4_ACE_DELETE_CHILD;
  78        if (perm & ACL_EXECUTE)
  79                mask |= NFS4_EXECUTE_MODE;
  80        return mask;
  81}
  82
  83static u32
  84deny_mask_from_posix(unsigned short perm, u32 flags)
  85{
  86        u32 mask = 0;
  87
  88        if (perm & ACL_READ)
  89                mask |= NFS4_READ_MODE;
  90        if (perm & ACL_WRITE)
  91                mask |= NFS4_WRITE_MODE;
  92        if ((perm & ACL_WRITE) && (flags & NFS4_ACL_DIR))
  93                mask |= NFS4_ACE_DELETE_CHILD;
  94        if (perm & ACL_EXECUTE)
  95                mask |= NFS4_EXECUTE_MODE;
  96        return mask;
  97}
  98
  99/* XXX: modify functions to return NFS errors; they're only ever
 100 * used by nfs code, after all.... */
 101
 102/* We only map from NFSv4 to POSIX ACLs when setting ACLs, when we err on the
 103 * side of being more restrictive, so the mode bit mapping below is
 104 * pessimistic.  An optimistic version would be needed to handle DENY's,
 105 * but we espect to coalesce all ALLOWs and DENYs before mapping to mode
 106 * bits. */
 107
 108static void
 109low_mode_from_nfs4(u32 perm, unsigned short *mode, unsigned int flags)
 110{
 111        u32 write_mode = NFS4_WRITE_MODE;
 112
 113        if (flags & NFS4_ACL_DIR)
 114                write_mode |= NFS4_ACE_DELETE_CHILD;
 115        *mode = 0;
 116        if ((perm & NFS4_READ_MODE) == NFS4_READ_MODE)
 117                *mode |= ACL_READ;
 118        if ((perm & write_mode) == write_mode)
 119                *mode |= ACL_WRITE;
 120        if ((perm & NFS4_EXECUTE_MODE) == NFS4_EXECUTE_MODE)
 121                *mode |= ACL_EXECUTE;
 122}
 123
 124struct ace_container {
 125        struct nfs4_ace  *ace;
 126        struct list_head  ace_l;
 127};
 128
 129static short ace2type(struct nfs4_ace *);
 130static void _posix_to_nfsv4_one(struct posix_acl *, struct nfs4_acl *,
 131                                unsigned int);
 132
 133struct nfs4_acl *
 134nfs4_acl_posix_to_nfsv4(struct posix_acl *pacl, struct posix_acl *dpacl,
 135                        unsigned int flags)
 136{
 137        struct nfs4_acl *acl;
 138        int size = 0;
 139
 140        if (pacl) {
 141                if (posix_acl_valid(pacl) < 0)
 142                        return ERR_PTR(-EINVAL);
 143                size += 2*pacl->a_count;
 144        }
 145        if (dpacl) {
 146                if (posix_acl_valid(dpacl) < 0)
 147                        return ERR_PTR(-EINVAL);
 148                size += 2*dpacl->a_count;
 149        }
 150
 151        /* Allocate for worst case: one (deny, allow) pair each: */
 152        acl = nfs4_acl_new(size);
 153        if (acl == NULL)
 154                return ERR_PTR(-ENOMEM);
 155
 156        if (pacl)
 157                _posix_to_nfsv4_one(pacl, acl, flags & ~NFS4_ACL_TYPE_DEFAULT);
 158
 159        if (dpacl)
 160                _posix_to_nfsv4_one(dpacl, acl, flags | NFS4_ACL_TYPE_DEFAULT);
 161
 162        return acl;
 163}
 164
 165struct posix_acl_summary {
 166        unsigned short owner;
 167        unsigned short users;
 168        unsigned short group;
 169        unsigned short groups;
 170        unsigned short other;
 171        unsigned short mask;
 172};
 173
 174static void
 175summarize_posix_acl(struct posix_acl *acl, struct posix_acl_summary *pas)
 176{
 177        struct posix_acl_entry *pa, *pe;
 178
 179        /*
 180         * Only pas.users and pas.groups need initialization; previous
 181         * posix_acl_valid() calls ensure that the other fields will be
 182         * initialized in the following loop.  But, just to placate gcc:
 183         */
 184        memset(pas, 0, sizeof(*pas));
 185        pas->mask = 07;
 186
 187        pe = acl->a_entries + acl->a_count;
 188
 189        FOREACH_ACL_ENTRY(pa, acl, pe) {
 190                switch (pa->e_tag) {
 191                        case ACL_USER_OBJ:
 192                                pas->owner = pa->e_perm;
 193                                break;
 194                        case ACL_GROUP_OBJ:
 195                                pas->group = pa->e_perm;
 196                                break;
 197                        case ACL_USER:
 198                                pas->users |= pa->e_perm;
 199                                break;
 200                        case ACL_GROUP:
 201                                pas->groups |= pa->e_perm;
 202                                break;
 203                        case ACL_OTHER:
 204                                pas->other = pa->e_perm;
 205                                break;
 206                        case ACL_MASK:
 207                                pas->mask = pa->e_perm;
 208                                break;
 209                }
 210        }
 211        /* We'll only care about effective permissions: */
 212        pas->users &= pas->mask;
 213        pas->group &= pas->mask;
 214        pas->groups &= pas->mask;
 215}
 216
 217/* We assume the acl has been verified with posix_acl_valid. */
 218static void
 219_posix_to_nfsv4_one(struct posix_acl *pacl, struct nfs4_acl *acl,
 220                                                unsigned int flags)
 221{
 222        struct posix_acl_entry *pa, *group_owner_entry;
 223        struct nfs4_ace *ace;
 224        struct posix_acl_summary pas;
 225        unsigned short deny;
 226        int eflag = ((flags & NFS4_ACL_TYPE_DEFAULT) ?
 227                NFS4_INHERITANCE_FLAGS | NFS4_ACE_INHERIT_ONLY_ACE : 0);
 228
 229        BUG_ON(pacl->a_count < 3);
 230        summarize_posix_acl(pacl, &pas);
 231
 232        pa = pacl->a_entries;
 233        ace = acl->aces + acl->naces;
 234
 235        /* We could deny everything not granted by the owner: */
 236        deny = ~pas.owner;
 237        /*
 238         * but it is equivalent (and simpler) to deny only what is not
 239         * granted by later entries:
 240         */
 241        deny &= pas.users | pas.group | pas.groups | pas.other;
 242        if (deny) {
 243                ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
 244                ace->flag = eflag;
 245                ace->access_mask = deny_mask_from_posix(deny, flags);
 246                ace->whotype = NFS4_ACL_WHO_OWNER;
 247                ace++;
 248                acl->naces++;
 249        }
 250
 251        ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
 252        ace->flag = eflag;
 253        ace->access_mask = mask_from_posix(pa->e_perm, flags | NFS4_ACL_OWNER);
 254        ace->whotype = NFS4_ACL_WHO_OWNER;
 255        ace++;
 256        acl->naces++;
 257        pa++;
 258
 259        while (pa->e_tag == ACL_USER) {
 260                deny = ~(pa->e_perm & pas.mask);
 261                deny &= pas.groups | pas.group | pas.other;
 262                if (deny) {
 263                        ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
 264                        ace->flag = eflag;
 265                        ace->access_mask = deny_mask_from_posix(deny, flags);
 266                        ace->whotype = NFS4_ACL_WHO_NAMED;
 267                        ace->who = pa->e_id;
 268                        ace++;
 269                        acl->naces++;
 270                }
 271                ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
 272                ace->flag = eflag;
 273                ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
 274                                                   flags);
 275                ace->whotype = NFS4_ACL_WHO_NAMED;
 276                ace->who = pa->e_id;
 277                ace++;
 278                acl->naces++;
 279                pa++;
 280        }
 281
 282        /* In the case of groups, we apply allow ACEs first, then deny ACEs,
 283         * since a user can be in more than one group.  */
 284
 285        /* allow ACEs */
 286
 287        group_owner_entry = pa;
 288
 289        ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
 290        ace->flag = eflag;
 291        ace->access_mask = mask_from_posix(pas.group, flags);
 292        ace->whotype = NFS4_ACL_WHO_GROUP;
 293        ace++;
 294        acl->naces++;
 295        pa++;
 296
 297        while (pa->e_tag == ACL_GROUP) {
 298                ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
 299                ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
 300                ace->access_mask = mask_from_posix(pa->e_perm & pas.mask,
 301                                                   flags);
 302                ace->whotype = NFS4_ACL_WHO_NAMED;
 303                ace->who = pa->e_id;
 304                ace++;
 305                acl->naces++;
 306                pa++;
 307        }
 308
 309        /* deny ACEs */
 310
 311        pa = group_owner_entry;
 312
 313        deny = ~pas.group & pas.other;
 314        if (deny) {
 315                ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
 316                ace->flag = eflag;
 317                ace->access_mask = deny_mask_from_posix(deny, flags);
 318                ace->whotype = NFS4_ACL_WHO_GROUP;
 319                ace++;
 320                acl->naces++;
 321        }
 322        pa++;
 323
 324        while (pa->e_tag == ACL_GROUP) {
 325                deny = ~(pa->e_perm & pas.mask);
 326                deny &= pas.other;
 327                if (deny) {
 328                        ace->type = NFS4_ACE_ACCESS_DENIED_ACE_TYPE;
 329                        ace->flag = eflag | NFS4_ACE_IDENTIFIER_GROUP;
 330                        ace->access_mask = deny_mask_from_posix(deny, flags);
 331                        ace->whotype = NFS4_ACL_WHO_NAMED;
 332                        ace->who = pa->e_id;
 333                        ace++;
 334                        acl->naces++;
 335                }
 336                pa++;
 337        }
 338
 339        if (pa->e_tag == ACL_MASK)
 340                pa++;
 341        ace->type = NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE;
 342        ace->flag = eflag;
 343        ace->access_mask = mask_from_posix(pa->e_perm, flags);
 344        ace->whotype = NFS4_ACL_WHO_EVERYONE;
 345        acl->naces++;
 346}
 347
 348static void
 349sort_pacl_range(struct posix_acl *pacl, int start, int end) {
 350        int sorted = 0, i;
 351        struct posix_acl_entry tmp;
 352
 353        /* We just do a bubble sort; easy to do in place, and we're not
 354         * expecting acl's to be long enough to justify anything more. */
 355        while (!sorted) {
 356                sorted = 1;
 357                for (i = start; i < end; i++) {
 358                        if (pacl->a_entries[i].e_id
 359                                        > pacl->a_entries[i+1].e_id) {
 360                                sorted = 0;
 361                                tmp = pacl->a_entries[i];
 362                                pacl->a_entries[i] = pacl->a_entries[i+1];
 363                                pacl->a_entries[i+1] = tmp;
 364                        }
 365                }
 366        }
 367}
 368
 369static void
 370sort_pacl(struct posix_acl *pacl)
 371{
 372        /* posix_acl_valid requires that users and groups be in order
 373         * by uid/gid. */
 374        int i, j;
 375
 376        if (pacl->a_count <= 4)
 377                return; /* no users or groups */
 378        i = 1;
 379        while (pacl->a_entries[i].e_tag == ACL_USER)
 380                i++;
 381        sort_pacl_range(pacl, 1, i-1);
 382
 383        BUG_ON(pacl->a_entries[i].e_tag != ACL_GROUP_OBJ);
 384        j = ++i;
 385        while (pacl->a_entries[j].e_tag == ACL_GROUP)
 386                j++;
 387        sort_pacl_range(pacl, i, j-1);
 388        return;
 389}
 390
 391/*
 392 * While processing the NFSv4 ACE, this maintains bitmasks representing
 393 * which permission bits have been allowed and which denied to a given
 394 * entity: */
 395struct posix_ace_state {
 396        u32 allow;
 397        u32 deny;
 398};
 399
 400struct posix_user_ace_state {
 401        uid_t uid;
 402        struct posix_ace_state perms;
 403};
 404
 405struct posix_ace_state_array {
 406        int n;
 407        struct posix_user_ace_state aces[];
 408};
 409
 410/*
 411 * While processing the NFSv4 ACE, this maintains the partial permissions
 412 * calculated so far: */
 413
 414struct posix_acl_state {
 415        int empty;
 416        struct posix_ace_state owner;
 417        struct posix_ace_state group;
 418        struct posix_ace_state other;
 419        struct posix_ace_state everyone;
 420        struct posix_ace_state mask; /* Deny unused in this case */
 421        struct posix_ace_state_array *users;
 422        struct posix_ace_state_array *groups;
 423};
 424
 425static int
 426init_state(struct posix_acl_state *state, int cnt)
 427{
 428        int alloc;
 429
 430        memset(state, 0, sizeof(struct posix_acl_state));
 431        state->empty = 1;
 432        /*
 433         * In the worst case, each individual acl could be for a distinct
 434         * named user or group, but we don't no which, so we allocate
 435         * enough space for either:
 436         */
 437        alloc = sizeof(struct posix_ace_state_array)
 438                + cnt*sizeof(struct posix_user_ace_state);
 439        state->users = kzalloc(alloc, GFP_KERNEL);
 440        if (!state->users)
 441                return -ENOMEM;
 442        state->groups = kzalloc(alloc, GFP_KERNEL);
 443        if (!state->groups) {
 444                kfree(state->users);
 445                return -ENOMEM;
 446        }
 447        return 0;
 448}
 449
 450static void
 451free_state(struct posix_acl_state *state) {
 452        kfree(state->users);
 453        kfree(state->groups);
 454}
 455
 456static inline void add_to_mask(struct posix_acl_state *state, struct posix_ace_state *astate)
 457{
 458        state->mask.allow |= astate->allow;
 459}
 460
 461/*
 462 * Certain bits (SYNCHRONIZE, DELETE, WRITE_OWNER, READ/WRITE_NAMED_ATTRS,
 463 * READ_ATTRIBUTES, READ_ACL) are currently unenforceable and don't translate
 464 * to traditional read/write/execute permissions.
 465 *
 466 * It's problematic to reject acls that use certain mode bits, because it
 467 * places the burden on users to learn the rules about which bits one
 468 * particular server sets, without giving the user a lot of help--we return an
 469 * error that could mean any number of different things.  To make matters
 470 * worse, the problematic bits might be introduced by some application that's
 471 * automatically mapping from some other acl model.
 472 *
 473 * So wherever possible we accept anything, possibly erring on the side of
 474 * denying more permissions than necessary.
 475 *
 476 * However we do reject *explicit* DENY's of a few bits representing
 477 * permissions we could never deny:
 478 */
 479
 480static inline int check_deny(u32 mask, int isowner)
 481{
 482        if (mask & (NFS4_ACE_READ_ATTRIBUTES | NFS4_ACE_READ_ACL))
 483                return -EINVAL;
 484        if (!isowner)
 485                return 0;
 486        if (mask & (NFS4_ACE_WRITE_ATTRIBUTES | NFS4_ACE_WRITE_ACL))
 487                return -EINVAL;
 488        return 0;
 489}
 490
 491static struct posix_acl *
 492posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
 493{
 494        struct posix_acl_entry *pace;
 495        struct posix_acl *pacl;
 496        int nace;
 497        int i, error = 0;
 498
 499        /*
 500         * ACLs with no ACEs are treated differently in the inheritable
 501         * and effective cases: when there are no inheritable ACEs, we
 502         * set a zero-length default posix acl:
 503         */
 504        if (state->empty && (flags & NFS4_ACL_TYPE_DEFAULT)) {
 505                pacl = posix_acl_alloc(0, GFP_KERNEL);
 506                return pacl ? pacl : ERR_PTR(-ENOMEM);
 507        }
 508        /*
 509         * When there are no effective ACEs, the following will end
 510         * up setting a 3-element effective posix ACL with all
 511         * permissions zero.
 512         */
 513        nace = 4 + state->users->n + state->groups->n;
 514        pacl = posix_acl_alloc(nace, GFP_KERNEL);
 515        if (!pacl)
 516                return ERR_PTR(-ENOMEM);
 517
 518        pace = pacl->a_entries;
 519        pace->e_tag = ACL_USER_OBJ;
 520        error = check_deny(state->owner.deny, 1);
 521        if (error)
 522                goto out_err;
 523        low_mode_from_nfs4(state->owner.allow, &pace->e_perm, flags);
 524        pace->e_id = ACL_UNDEFINED_ID;
 525
 526        for (i=0; i < state->users->n; i++) {
 527                pace++;
 528                pace->e_tag = ACL_USER;
 529                error = check_deny(state->users->aces[i].perms.deny, 0);
 530                if (error)
 531                        goto out_err;
 532                low_mode_from_nfs4(state->users->aces[i].perms.allow,
 533                                        &pace->e_perm, flags);
 534                pace->e_id = state->users->aces[i].uid;
 535                add_to_mask(state, &state->users->aces[i].perms);
 536        }
 537
 538        pace++;
 539        pace->e_tag = ACL_GROUP_OBJ;
 540        error = check_deny(state->group.deny, 0);
 541        if (error)
 542                goto out_err;
 543        low_mode_from_nfs4(state->group.allow, &pace->e_perm, flags);
 544        pace->e_id = ACL_UNDEFINED_ID;
 545        add_to_mask(state, &state->group);
 546
 547        for (i=0; i < state->groups->n; i++) {
 548                pace++;
 549                pace->e_tag = ACL_GROUP;
 550                error = check_deny(state->groups->aces[i].perms.deny, 0);
 551                if (error)
 552                        goto out_err;
 553                low_mode_from_nfs4(state->groups->aces[i].perms.allow,
 554                                        &pace->e_perm, flags);
 555                pace->e_id = state->groups->aces[i].uid;
 556                add_to_mask(state, &state->groups->aces[i].perms);
 557        }
 558
 559        pace++;
 560        pace->e_tag = ACL_MASK;
 561        low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags);
 562        pace->e_id = ACL_UNDEFINED_ID;
 563
 564        pace++;
 565        pace->e_tag = ACL_OTHER;
 566        error = check_deny(state->other.deny, 0);
 567        if (error)
 568                goto out_err;
 569        low_mode_from_nfs4(state->other.allow, &pace->e_perm, flags);
 570        pace->e_id = ACL_UNDEFINED_ID;
 571
 572        return pacl;
 573out_err:
 574        posix_acl_release(pacl);
 575        return ERR_PTR(error);
 576}
 577
 578static inline void allow_bits(struct posix_ace_state *astate, u32 mask)
 579{
 580        /* Allow all bits in the mask not already denied: */
 581        astate->allow |= mask & ~astate->deny;
 582}
 583
 584static inline void deny_bits(struct posix_ace_state *astate, u32 mask)
 585{
 586        /* Deny all bits in the mask not already allowed: */
 587        astate->deny |= mask & ~astate->allow;
 588}
 589
 590static int find_uid(struct posix_acl_state *state, struct posix_ace_state_array *a, uid_t uid)
 591{
 592        int i;
 593
 594        for (i = 0; i < a->n; i++)
 595                if (a->aces[i].uid == uid)
 596                        return i;
 597        /* Not found: */
 598        a->n++;
 599        a->aces[i].uid = uid;
 600        a->aces[i].perms.allow = state->everyone.allow;
 601        a->aces[i].perms.deny  = state->everyone.deny;
 602
 603        return i;
 604}
 605
 606static void deny_bits_array(struct posix_ace_state_array *a, u32 mask)
 607{
 608        int i;
 609
 610        for (i=0; i < a->n; i++)
 611                deny_bits(&a->aces[i].perms, mask);
 612}
 613
 614static void allow_bits_array(struct posix_ace_state_array *a, u32 mask)
 615{
 616        int i;
 617
 618        for (i=0; i < a->n; i++)
 619                allow_bits(&a->aces[i].perms, mask);
 620}
 621
 622static void process_one_v4_ace(struct posix_acl_state *state,
 623                                struct nfs4_ace *ace)
 624{
 625        u32 mask = ace->access_mask;
 626        int i;
 627
 628        state->empty = 0;
 629
 630        switch (ace2type(ace)) {
 631        case ACL_USER_OBJ:
 632                if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 633                        allow_bits(&state->owner, mask);
 634                } else {
 635                        deny_bits(&state->owner, mask);
 636                }
 637                break;
 638        case ACL_USER:
 639                i = find_uid(state, state->users, ace->who);
 640                if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 641                        allow_bits(&state->users->aces[i].perms, mask);
 642                } else {
 643                        deny_bits(&state->users->aces[i].perms, mask);
 644                        mask = state->users->aces[i].perms.deny;
 645                        deny_bits(&state->owner, mask);
 646                }
 647                break;
 648        case ACL_GROUP_OBJ:
 649                if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 650                        allow_bits(&state->group, mask);
 651                } else {
 652                        deny_bits(&state->group, mask);
 653                        mask = state->group.deny;
 654                        deny_bits(&state->owner, mask);
 655                        deny_bits(&state->everyone, mask);
 656                        deny_bits_array(state->users, mask);
 657                        deny_bits_array(state->groups, mask);
 658                }
 659                break;
 660        case ACL_GROUP:
 661                i = find_uid(state, state->groups, ace->who);
 662                if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 663                        allow_bits(&state->groups->aces[i].perms, mask);
 664                } else {
 665                        deny_bits(&state->groups->aces[i].perms, mask);
 666                        mask = state->groups->aces[i].perms.deny;
 667                        deny_bits(&state->owner, mask);
 668                        deny_bits(&state->group, mask);
 669                        deny_bits(&state->everyone, mask);
 670                        deny_bits_array(state->users, mask);
 671                        deny_bits_array(state->groups, mask);
 672                }
 673                break;
 674        case ACL_OTHER:
 675                if (ace->type == NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE) {
 676                        allow_bits(&state->owner, mask);
 677                        allow_bits(&state->group, mask);
 678                        allow_bits(&state->other, mask);
 679                        allow_bits(&state->everyone, mask);
 680                        allow_bits_array(state->users, mask);
 681                        allow_bits_array(state->groups, mask);
 682                } else {
 683                        deny_bits(&state->owner, mask);
 684                        deny_bits(&state->group, mask);
 685                        deny_bits(&state->other, mask);
 686                        deny_bits(&state->everyone, mask);
 687                        deny_bits_array(state->users, mask);
 688                        deny_bits_array(state->groups, mask);
 689                }
 690        }
 691}
 692
 693int nfs4_acl_nfsv4_to_posix(struct nfs4_acl *acl, struct posix_acl **pacl,
 694                            struct posix_acl **dpacl, unsigned int flags)
 695{
 696        struct posix_acl_state effective_acl_state, default_acl_state;
 697        struct nfs4_ace *ace;
 698        int ret;
 699
 700        ret = init_state(&effective_acl_state, acl->naces);
 701        if (ret)
 702                return ret;
 703        ret = init_state(&default_acl_state, acl->naces);
 704        if (ret)
 705                goto out_estate;
 706        ret = -EINVAL;
 707        for (ace = acl->aces; ace < acl->aces + acl->naces; ace++) {
 708                if (ace->type != NFS4_ACE_ACCESS_ALLOWED_ACE_TYPE &&
 709                    ace->type != NFS4_ACE_ACCESS_DENIED_ACE_TYPE)
 710                        goto out_dstate;
 711                if (ace->flag & ~NFS4_SUPPORTED_FLAGS)
 712                        goto out_dstate;
 713                if ((ace->flag & NFS4_INHERITANCE_FLAGS) == 0) {
 714                        process_one_v4_ace(&effective_acl_state, ace);
 715                        continue;
 716                }
 717                if (!(flags & NFS4_ACL_DIR))
 718                        goto out_dstate;
 719                /*
 720                 * Note that when only one of FILE_INHERIT or DIRECTORY_INHERIT
 721                 * is set, we're effectively turning on the other.  That's OK,
 722                 * according to rfc 3530.
 723                 */
 724                process_one_v4_ace(&default_acl_state, ace);
 725
 726                if (!(ace->flag & NFS4_ACE_INHERIT_ONLY_ACE))
 727                        process_one_v4_ace(&effective_acl_state, ace);
 728        }
 729        *pacl = posix_state_to_acl(&effective_acl_state, flags);
 730        if (IS_ERR(*pacl)) {
 731                ret = PTR_ERR(*pacl);
 732                *pacl = NULL;
 733                goto out_dstate;
 734        }
 735        *dpacl = posix_state_to_acl(&default_acl_state,
 736                                                flags | NFS4_ACL_TYPE_DEFAULT);
 737        if (IS_ERR(*dpacl)) {
 738                ret = PTR_ERR(*dpacl);
 739                *dpacl = NULL;
 740                posix_acl_release(*pacl);
 741                *pacl = NULL;
 742                goto out_dstate;
 743        }
 744        sort_pacl(*pacl);
 745        sort_pacl(*dpacl);
 746        ret = 0;
 747out_dstate:
 748        free_state(&default_acl_state);
 749out_estate:
 750        free_state(&effective_acl_state);
 751        return ret;
 752}
 753
 754static short
 755ace2type(struct nfs4_ace *ace)
 756{
 757        switch (ace->whotype) {
 758                case NFS4_ACL_WHO_NAMED:
 759                        return (ace->flag & NFS4_ACE_IDENTIFIER_GROUP ?
 760                                        ACL_GROUP : ACL_USER);
 761                case NFS4_ACL_WHO_OWNER:
 762                        return ACL_USER_OBJ;
 763                case NFS4_ACL_WHO_GROUP:
 764                        return ACL_GROUP_OBJ;
 765                case NFS4_ACL_WHO_EVERYONE:
 766                        return ACL_OTHER;
 767        }
 768        BUG();
 769        return -1;
 770}
 771
 772EXPORT_SYMBOL(nfs4_acl_posix_to_nfsv4);
 773EXPORT_SYMBOL(nfs4_acl_nfsv4_to_posix);
 774
 775struct nfs4_acl *
 776nfs4_acl_new(int n)
 777{
 778        struct nfs4_acl *acl;
 779
 780        acl = kmalloc(sizeof(*acl) + n*sizeof(struct nfs4_ace), GFP_KERNEL);
 781        if (acl == NULL)
 782                return NULL;
 783        acl->naces = 0;
 784        return acl;
 785}
 786
 787static struct {
 788        char *string;
 789        int   stringlen;
 790        int type;
 791} s2t_map[] = {
 792        {
 793                .string    = "OWNER@",
 794                .stringlen = sizeof("OWNER@") - 1,
 795                .type      = NFS4_ACL_WHO_OWNER,
 796        },
 797        {
 798                .string    = "GROUP@",
 799                .stringlen = sizeof("GROUP@") - 1,
 800                .type      = NFS4_ACL_WHO_GROUP,
 801        },
 802        {
 803                .string    = "EVERYONE@",
 804                .stringlen = sizeof("EVERYONE@") - 1,
 805                .type      = NFS4_ACL_WHO_EVERYONE,
 806        },
 807};
 808
 809int
 810nfs4_acl_get_whotype(char *p, u32 len)
 811{
 812        int i;
 813
 814        for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
 815                if (s2t_map[i].stringlen == len &&
 816                                0 == memcmp(s2t_map[i].string, p, len))
 817                        return s2t_map[i].type;
 818        }
 819        return NFS4_ACL_WHO_NAMED;
 820}
 821
 822int
 823nfs4_acl_write_who(int who, char *p)
 824{
 825        int i;
 826
 827        for (i = 0; i < ARRAY_SIZE(s2t_map); i++) {
 828                if (s2t_map[i].type == who) {
 829                        memcpy(p, s2t_map[i].string, s2t_map[i].stringlen);
 830                        return s2t_map[i].stringlen;
 831                }
 832        }
 833        BUG();
 834        return -1;
 835}
 836
 837EXPORT_SYMBOL(nfs4_acl_new);
 838EXPORT_SYMBOL(nfs4_acl_get_whotype);
 839EXPORT_SYMBOL(nfs4_acl_write_who);
 840
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