sys/kern/subr_acl_nfs4.c

   1 /*-
   2  * Copyright (c) 2008-2009 Edward Tomasz Napierała <trasz@FreeBSD.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 /*
  28  * ACL support routines specific to NFSv4 access control lists.  These are
  29  * utility routines for code common across file systems implementing NFSv4
  30  * ACLs.
  31  */
  32
  33 #ifdef _KERNEL
  34 #include <sys/cdefs.h>
  35 __FBSDID("$FreeBSD$");
  36
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/mount.h>
  40 #include <sys/priv.h>
  41 #include <sys/vnode.h>
  42 #include <sys/errno.h>
  43 #include <sys/stat.h>
  44 #include <sys/acl.h>
  45 #else
  46 #include <errno.h>
  47 #include <assert.h>
  48 #include <sys/acl.h>
  49 #include <sys/stat.h>
  50 #define KASSERT(a, b) assert(a)
  51 #define CTASSERT(a)
  52 #endif /* _KERNEL */
  53
  54 #ifdef _KERNEL
  55
  56 static struct {
  57         accmode_t accmode;
  58         int mask;
  59 } accmode2mask[] = {{VREAD, ACL_READ_DATA},
  60                     {VWRITE, ACL_WRITE_DATA},
  61                     {VAPPEND, ACL_APPEND_DATA},
  62                     {VEXEC, ACL_EXECUTE},
  63                     {VREAD_NAMED_ATTRS, ACL_READ_NAMED_ATTRS},
  64                     {VWRITE_NAMED_ATTRS, ACL_WRITE_NAMED_ATTRS},
  65                     {VDELETE_CHILD, ACL_DELETE_CHILD},
  66                     {VREAD_ATTRIBUTES, ACL_READ_ATTRIBUTES},
  67                     {VWRITE_ATTRIBUTES, ACL_WRITE_ATTRIBUTES},
  68                     {VDELETE, ACL_DELETE},
  69                     {VREAD_ACL, ACL_READ_ACL},
  70                     {VWRITE_ACL, ACL_WRITE_ACL},
  71                     {VWRITE_OWNER, ACL_WRITE_OWNER},
  72                     {VSYNCHRONIZE, ACL_SYNCHRONIZE},
  73                     {0, 0}};
  74
  75 static int
  76 _access_mask_from_accmode(accmode_t accmode)
  77 {
  78         int access_mask = 0, i;
  79
  80         for (i = 0; accmode2mask[i].accmode != 0; i++) {
  81                 if (accmode & accmode2mask[i].accmode)
  82                         access_mask |= accmode2mask[i].mask;
  83         }
  84
  85         /*
  86          * VAPPEND is just a modifier for VWRITE; if the caller asked
  87          * for 'VAPPEND | VWRITE', we want to check for ACL_APPEND_DATA only.
  88          */
  89         if (access_mask & ACL_APPEND_DATA)
  90                 access_mask &= ~ACL_WRITE_DATA;
  91
  92         return (access_mask);
  93 }
  94
  95 /*
  96  * Return 0, iff access is allowed, 1 otherwise.
  97  */
  98 static int
  99 _acl_denies(const struct acl *aclp, int access_mask, struct ucred *cred,
 100     int file_uid, int file_gid, int *denied_explicitly)
 101 {
 102         int i;
 103         const struct acl_entry *entry;
 104
 105         if (denied_explicitly != NULL)
 106                 *denied_explicitly = 0;
 107
 108         KASSERT(aclp->acl_cnt > 0, ("aclp->acl_cnt > 0"));
 109         KASSERT(aclp->acl_cnt <= ACL_MAX_ENTRIES,
 110             ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
 111
 112         for (i = 0; i < aclp->acl_cnt; i++) {
 113                 entry = &(aclp->acl_entry[i]);
 114
 115                 if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
 116                     entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
 117                         continue;
 118                 if (entry->ae_flags & ACL_ENTRY_INHERIT_ONLY)
 119                         continue;
 120                 switch (entry->ae_tag) {
 121                 case ACL_USER_OBJ:
 122                         if (file_uid != cred->cr_uid)
 123                                 continue;
 124                         break;
 125                 case ACL_USER:
 126                         if (entry->ae_id != cred->cr_uid)
 127                                 continue;
 128                         break;
 129                 case ACL_GROUP_OBJ:
 130                         if (!groupmember(file_gid, cred))
 131                                 continue;
 132                         break;
 133                 case ACL_GROUP:
 134                         if (!groupmember(entry->ae_id, cred))
 135                                 continue;
 136                         break;
 137                 default:
 138                         KASSERT(entry->ae_tag == ACL_EVERYONE,
 139                             ("entry->ae_tag == ACL_EVERYONE"));
 140                 }
 141
 142                 if (entry->ae_entry_type == ACL_ENTRY_TYPE_DENY) {
 143                         if (entry->ae_perm & access_mask) {
 144                                 if (denied_explicitly != NULL)
 145                                         *denied_explicitly = 1;
 146                                 return (1);
 147                         }
 148                 }
 149
 150                 access_mask &= ~(entry->ae_perm);
 151                 if (access_mask == 0)
 152                         return (0);
 153         }
 154
 155         return (1);
 156 }
 157
 158 int
 159 vaccess_acl_nfs4(enum vtype type, uid_t file_uid, gid_t file_gid,
 160     struct acl *aclp, accmode_t accmode, struct ucred *cred, int *privused)
 161 {
 162         accmode_t priv_granted = 0;
 163         int denied, explicitly_denied, access_mask, is_directory,
 164             must_be_owner = 0;
 165
 166         if (privused != NULL)
 167                 *privused = 0;
 168
 169         if (accmode & VADMIN)
 170                 must_be_owner = 1;
 171
 172         /*
 173          * Ignore VSYNCHRONIZE permission.
 174          */
 175         accmode &= ~VSYNCHRONIZE;
 176
 177         access_mask = _access_mask_from_accmode(accmode);
 178
 179         if (type == VDIR)
 180                 is_directory = 1;
 181         else
 182                 is_directory = 0;
 183
 184         /*
 185          * File owner is always allowed to read and write the ACL
 186          * and basic attributes.  This is to prevent a situation
 187          * where user would change ACL in a way that prevents him
 188          * from undoing the change.
 189          */
 190         if (file_uid == cred->cr_uid)
 191                 access_mask &= ~(ACL_READ_ACL | ACL_WRITE_ACL |
 192                     ACL_READ_ATTRIBUTES | ACL_WRITE_ATTRIBUTES);
 193
 194         /*
 195          * Ignore append permission for regular files; use write
 196          * permission instead.
 197          */
 198         if (!is_directory && (access_mask & ACL_APPEND_DATA)) {
 199                 access_mask &= ~ACL_APPEND_DATA;
 200                 access_mask |= ACL_WRITE_DATA;
 201         }
 202
 203         denied = _acl_denies(aclp, access_mask, cred, file_uid, file_gid,
 204             &explicitly_denied);
 205
 206         if (must_be_owner) {
 207                 if (file_uid != cred->cr_uid)
 208                         denied = EPERM;
 209         }
 210
 211         if (!denied)
 212                 return (0);
 213
 214         /*
 215          * Access failed.  Iff it was not denied explicitly and
 216          * VEXPLICIT_DENY flag was specified, allow access.
 217          */
 218         if ((accmode & VEXPLICIT_DENY) && explicitly_denied == 0)
 219                 return (0);
 220
 221         accmode &= ~VEXPLICIT_DENY;
 222
 223         /*
 224          * No match.  Try to use privileges, if there are any.
 225          */
 226         if (is_directory) {
 227                 if ((accmode & VEXEC) && !priv_check_cred(cred,
 228                     PRIV_VFS_LOOKUP, 0))
 229                         priv_granted |= VEXEC;
 230         } else {
 231                 if ((accmode & VEXEC) && !priv_check_cred(cred,
 232                     PRIV_VFS_EXEC, 0))
 233                         priv_granted |= VEXEC;
 234         }
 235
 236         if ((accmode & VREAD) && !priv_check_cred(cred, PRIV_VFS_READ, 0))
 237                 priv_granted |= VREAD;
 238
 239         if ((accmode & (VWRITE | VAPPEND | VDELETE_CHILD)) &&
 240             !priv_check_cred(cred, PRIV_VFS_WRITE, 0))
 241                 priv_granted |= (VWRITE | VAPPEND | VDELETE_CHILD);
 242
 243         if ((accmode & VADMIN_PERMS) &&
 244             !priv_check_cred(cred, PRIV_VFS_ADMIN, 0))
 245                 priv_granted |= VADMIN_PERMS;
 246
 247         if ((accmode & VSTAT_PERMS) &&
 248             !priv_check_cred(cred, PRIV_VFS_STAT, 0))
 249                 priv_granted |= VSTAT_PERMS;
 250
 251         if ((accmode & priv_granted) == accmode) {
 252                 if (privused != NULL)
 253                         *privused = 1;
 254
 255                 return (0);
 256         }
 257
 258         if (accmode & (VADMIN_PERMS | VDELETE_CHILD | VDELETE))
 259                 denied = EPERM;
 260         else
 261                 denied = EACCES;
 262
 263         return (denied);
 264 }
 265 #endif /* _KERNEL */
 266
 267 static int
 268 _acl_entry_matches(struct acl_entry *entry, acl_tag_t tag, acl_perm_t perm,
 269     acl_entry_type_t entry_type)
 270 {
 271         if (entry->ae_tag != tag)
 272                 return (0);
 273
 274         if (entry->ae_id != ACL_UNDEFINED_ID)
 275                 return (0);
 276
 277         if (entry->ae_perm != perm)
 278                 return (0);
 279
 280         if (entry->ae_entry_type != entry_type)
 281                 return (0);
 282
 283         if (entry->ae_flags != 0)
 284                 return (0);
 285
 286         return (1);
 287 }
 288
 289 static struct acl_entry *
 290 _acl_append(struct acl *aclp, acl_tag_t tag, acl_perm_t perm,
 291     acl_entry_type_t entry_type)
 292 {
 293         struct acl_entry *entry;
 294
 295         KASSERT(aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES,
 296             ("aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES"));
 297
 298         entry = &(aclp->acl_entry[aclp->acl_cnt]);
 299         aclp->acl_cnt++;
 300
 301         entry->ae_tag = tag;
 302         entry->ae_id = ACL_UNDEFINED_ID;
 303         entry->ae_perm = perm;
 304         entry->ae_entry_type = entry_type;
 305         entry->ae_flags = 0;
 306
 307         return (entry);
 308 }
 309
 310 static struct acl_entry *
 311 _acl_duplicate_entry(struct acl *aclp, int entry_index)
 312 {
 313         int i;
 314
 315         KASSERT(aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES,
 316             ("aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES"));
 317
 318         for (i = aclp->acl_cnt; i > entry_index; i--)
 319                 aclp->acl_entry[i] = aclp->acl_entry[i - 1];
 320
 321         aclp->acl_cnt++;
 322
 323         return (&(aclp->acl_entry[entry_index + 1]));
 324 }
 325
 326 /*
 327  * Calculate trivial ACL in a manner compatible with PSARC/2010/029.
 328  * Note that this results in an ACL different from (but semantically
 329  * equal to) the "canonical six" trivial ACL computed using algorithm
 330  * described in draft-ietf-nfsv4-minorversion1-03.txt, 3.16.6.2.
 331  */
 332 void
 333 acl_nfs4_trivial_from_mode(struct acl *aclp, mode_t mode)
 334 {
 335         acl_perm_t user_allow_first = 0, user_deny = 0, group_deny = 0;
 336         acl_perm_t user_allow, group_allow, everyone_allow;
 337
 338         KASSERT(aclp->acl_cnt == 0, ("aclp->acl_cnt == 0"));
 339
 340         user_allow = group_allow = everyone_allow = ACL_READ_ACL |
 341             ACL_READ_ATTRIBUTES | ACL_READ_NAMED_ATTRS | ACL_SYNCHRONIZE;
 342         user_allow |= ACL_WRITE_ACL | ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
 343             ACL_WRITE_NAMED_ATTRS;
 344
 345         if (mode & S_IRUSR)
 346                 user_allow |= ACL_READ_DATA;
 347         if (mode & S_IWUSR)
 348                 user_allow |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
 349         if (mode & S_IXUSR)
 350                 user_allow |= ACL_EXECUTE;
 351
 352         if (mode & S_IRGRP)
 353                 group_allow |= ACL_READ_DATA;
 354         if (mode & S_IWGRP)
 355                 group_allow |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
 356         if (mode & S_IXGRP)
 357                 group_allow |= ACL_EXECUTE;
 358
 359         if (mode & S_IROTH)
 360                 everyone_allow |= ACL_READ_DATA;
 361         if (mode & S_IWOTH)
 362                 everyone_allow |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
 363         if (mode & S_IXOTH)
 364                 everyone_allow |= ACL_EXECUTE;
 365
 366         user_deny = ((group_allow | everyone_allow) & ~user_allow);
 367         group_deny = everyone_allow & ~group_allow;
 368         user_allow_first = group_deny & ~user_deny;
 369
 370 #if 1
 371         /*
 372          * This is a workaround for what looks like a bug in ZFS - trivial
 373          * ACL for mode 0077 should look like this:
 374          *
 375          *    owner@:rwxp----------:------:deny
 376          *    owner@:------aARWcCos:------:allow
 377          *    group@:rwxp--a-R-c--s:------:allow
 378          * everyone@:rwxp--a-R-c--s:------:allow
 379          *
 380          * Instead, ZFS makes it like this:
 381          *
 382          *    owner@:rwx-----------:------:deny
 383          *    owner@:------aARWcCos:------:allow
 384          *    group@:rwxp--a-R-c--s:------:allow
 385          * everyone@:rwxp--a-R-c--s:------:allow
 386          */
 387         user_allow_first &= ~ACL_APPEND_DATA;
 388         user_deny &= ~ACL_APPEND_DATA;
 389         group_deny &= ~ACL_APPEND_DATA;
 390 #endif
 391
 392         if (user_allow_first != 0)
 393                 _acl_append(aclp, ACL_USER_OBJ, user_allow_first, ACL_ENTRY_TYPE_ALLOW);
 394         if (user_deny != 0)
 395                 _acl_append(aclp, ACL_USER_OBJ, user_deny, ACL_ENTRY_TYPE_DENY);
 396         if (group_deny != 0)
 397                 _acl_append(aclp, ACL_GROUP_OBJ, group_deny, ACL_ENTRY_TYPE_DENY);
 398         _acl_append(aclp, ACL_USER_OBJ, user_allow, ACL_ENTRY_TYPE_ALLOW);
 399         _acl_append(aclp, ACL_GROUP_OBJ, group_allow, ACL_ENTRY_TYPE_ALLOW);
 400         _acl_append(aclp, ACL_EVERYONE, everyone_allow, ACL_ENTRY_TYPE_ALLOW);
 401 }
 402
 403 void
 404 acl_nfs4_sync_acl_from_mode(struct acl *aclp, mode_t mode, int file_owner_id)
 405 {
 406         int i, meets, must_append;
 407         struct acl_entry *entry, *copy, *previous,
 408             *a1, *a2, *a3, *a4, *a5, *a6;
 409         mode_t amode;
 410         const int READ = 04;
 411         const int WRITE = 02;
 412         const int EXEC = 01;
 413
 414         KASSERT(aclp->acl_cnt >= 0, ("aclp->acl_cnt >= 0"));
 415         KASSERT(aclp->acl_cnt <= ACL_MAX_ENTRIES,
 416             ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
 417
 418         /*
 419          * NFSv4 Minor Version 1, draft-ietf-nfsv4-minorversion1-03.txt
 420          *
 421          * 3.16.6.3. Applying a Mode to an Existing ACL
 422          */
 423
 424         /*
 425          * 1. For each ACE:
 426          */
 427         for (i = 0; i < aclp->acl_cnt; i++) {
 428                 entry = &(aclp->acl_entry[i]);
 429
 430                 /*
 431                  * 1.1. If the type is neither ALLOW or DENY - skip.
 432                  */
 433                 if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
 434                     entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
 435                         continue;
 436
 437                 /*
 438                  * 1.2. If ACL_ENTRY_INHERIT_ONLY is set - skip.
 439                  */
 440                 if (entry->ae_flags & ACL_ENTRY_INHERIT_ONLY)
 441                         continue;
 442
 443                 /*
 444                  * 1.3. If ACL_ENTRY_FILE_INHERIT or ACL_ENTRY_DIRECTORY_INHERIT
 445                  *      are set:
 446                  */
 447                 if (entry->ae_flags &
 448                     (ACL_ENTRY_FILE_INHERIT | ACL_ENTRY_DIRECTORY_INHERIT)) {
 449                         /*
 450                          * 1.3.1. A copy of the current ACE is made, and placed
 451                          *        in the ACL immediately following the current
 452                          *        ACE.
 453                          */
 454                         copy = _acl_duplicate_entry(aclp, i);
 455
 456                         /*
 457                          * 1.3.2. In the first ACE, the flag
 458                          *        ACL_ENTRY_INHERIT_ONLY is set.
 459                          */
 460                         entry->ae_flags |= ACL_ENTRY_INHERIT_ONLY;
 461
 462                         /*
 463                          * 1.3.3. In the second ACE, the following flags
 464                          *        are cleared:
 465                          *        ACL_ENTRY_FILE_INHERIT,
 466                          *        ACL_ENTRY_DIRECTORY_INHERIT,
 467                          *        ACL_ENTRY_NO_PROPAGATE_INHERIT.
 468                          */
 469                         copy->ae_flags &= ~(ACL_ENTRY_FILE_INHERIT |
 470                             ACL_ENTRY_DIRECTORY_INHERIT |
 471                             ACL_ENTRY_NO_PROPAGATE_INHERIT);
 472
 473                         /*
 474                          * The algorithm continues on with the second ACE.
 475                          */
 476                         i++;
 477                         entry = copy;
 478                 }
 479
 480                 /*
 481                  * 1.4. If it's owner@, group@ or everyone@ entry, clear
 482                  *      ACL_READ_DATA, ACL_WRITE_DATA, ACL_APPEND_DATA
 483                  *      and ACL_EXECUTE.  Continue to the next entry.
 484                  */
 485                 if (entry->ae_tag == ACL_USER_OBJ ||
 486                     entry->ae_tag == ACL_GROUP_OBJ ||
 487                     entry->ae_tag == ACL_EVERYONE) {
 488                         entry->ae_perm &= ~(ACL_READ_DATA | ACL_WRITE_DATA |
 489                             ACL_APPEND_DATA | ACL_EXECUTE);
 490                         continue;
 491                 }
 492
 493                 /*
 494                  * 1.5. Otherwise, if the "who" field did not match one
 495                  *      of OWNER@, GROUP@, EVERYONE@:
 496                  *
 497                  * 1.5.1. If the type is ALLOW, check the preceding ACE.
 498                  *        If it does not meet all of the following criteria:
 499                  */
 500                 if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW)
 501                         continue;
 502
 503                 meets = 0;
 504                 if (i > 0) {
 505                         meets = 1;
 506                         previous = &(aclp->acl_entry[i - 1]);
 507
 508                         /*
 509                          * 1.5.1.1. The type field is DENY,
 510                          */
 511                         if (previous->ae_entry_type != ACL_ENTRY_TYPE_DENY)
 512                                 meets = 0;
 513
 514                         /*
 515                          * 1.5.1.2. The "who" field is the same as the current
 516                          *          ACE,
 517                          *
 518                          * 1.5.1.3. The flag bit ACE4_IDENTIFIER_GROUP
 519                          *          is the same as it is in the current ACE,
 520                          *          and no other flag bits are set,
 521                          */
 522                         if (previous->ae_id != entry->ae_id ||
 523                             previous->ae_tag != entry->ae_tag)
 524                                 meets = 0;
 525
 526                         if (previous->ae_flags)
 527                                 meets = 0;
 528
 529                         /*
 530                          * 1.5.1.4. The mask bits are a subset of the mask bits
 531                          *          of the current ACE, and are also subset of
 532                          *          the following: ACL_READ_DATA,
 533                          *          ACL_WRITE_DATA, ACL_APPEND_DATA, ACL_EXECUTE
 534                          */
 535                         if (previous->ae_perm & ~(entry->ae_perm))
 536                                 meets = 0;
 537
 538                         if (previous->ae_perm & ~(ACL_READ_DATA |
 539                             ACL_WRITE_DATA | ACL_APPEND_DATA | ACL_EXECUTE))
 540                                 meets = 0;
 541                 }
 542
 543                 if (!meets) {
 544                         /*
 545                          * Then the ACE of type DENY, with a who equal
 546                          * to the current ACE, flag bits equal to
 547                          * (<current ACE flags> & <ACE_IDENTIFIER_GROUP>)
 548                          * and no mask bits, is prepended.
 549                          */
 550                         previous = entry;
 551                         entry = _acl_duplicate_entry(aclp, i);
 552
 553                         /* Adjust counter, as we've just added an entry. */
 554                         i++;
 555
 556                         previous->ae_tag = entry->ae_tag;
 557                         previous->ae_id = entry->ae_id;
 558                         previous->ae_flags = entry->ae_flags;
 559                         previous->ae_perm = 0;
 560                         previous->ae_entry_type = ACL_ENTRY_TYPE_DENY;
 561                 }
 562
 563                 /*
 564                  * 1.5.2. The following modifications are made to the prepended
 565                  *        ACE.  The intent is to mask the following ACE
 566                  *        to disallow ACL_READ_DATA, ACL_WRITE_DATA,
 567                  *        ACL_APPEND_DATA, or ACL_EXECUTE, based upon the group
 568                  *        permissions of the new mode.  As a special case,
 569                  *        if the ACE matches the current owner of the file,
 570                  *        the owner bits are used, rather than the group bits.
 571                  *        This is reflected in the algorithm below.
 572                  */
 573                 amode = mode >> 3;
 574
 575                 /*
 576                  * If ACE4_IDENTIFIER_GROUP is not set, and the "who" field
 577                  * in ACE matches the owner of the file, we shift amode three
 578                  * more bits, in order to have the owner permission bits
 579                  * placed in the three low order bits of amode.
 580                  */
 581                 if (entry->ae_tag == ACL_USER && entry->ae_id == file_owner_id)
 582                         amode = amode >> 3;
 583
 584                 if (entry->ae_perm & ACL_READ_DATA) {
 585                         if (amode & READ)
 586                                 previous->ae_perm &= ~ACL_READ_DATA;
 587                         else
 588                                 previous->ae_perm |= ACL_READ_DATA;
 589                 }
 590
 591                 if (entry->ae_perm & ACL_WRITE_DATA) {
 592                         if (amode & WRITE)
 593                                 previous->ae_perm &= ~ACL_WRITE_DATA;
 594                         else
 595                                 previous->ae_perm |= ACL_WRITE_DATA;
 596                 }
 597
 598                 if (entry->ae_perm & ACL_APPEND_DATA) {
 599                         if (amode & WRITE)
 600                                 previous->ae_perm &= ~ACL_APPEND_DATA;
 601                         else
 602                                 previous->ae_perm |= ACL_APPEND_DATA;
 603                 }
 604
 605                 if (entry->ae_perm & ACL_EXECUTE) {
 606                         if (amode & EXEC)
 607                                 previous->ae_perm &= ~ACL_EXECUTE;
 608                         else
 609                                 previous->ae_perm |= ACL_EXECUTE;
 610                 }
 611
 612                 /*
 613                  * 1.5.3. If ACE4_IDENTIFIER_GROUP is set in the flags
 614                  *        of the ALLOW ace:
 615                  *
 616                  * XXX: This point is not there in the Falkner's draft.
 617                  */
 618                 if (entry->ae_tag == ACL_GROUP &&
 619                     entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW) {
 620                         mode_t extramode, ownermode;
 621                         extramode = (mode >> 3) & 07;
 622                         ownermode = mode >> 6;
 623                         extramode &= ~ownermode;
 624
 625                         if (extramode) {
 626                                 if (extramode & READ) {
 627                                         entry->ae_perm &= ~ACL_READ_DATA;
 628                                         previous->ae_perm &= ~ACL_READ_DATA;
 629                                 }
 630
 631                                 if (extramode & WRITE) {
 632                                         entry->ae_perm &=
 633                                             ~(ACL_WRITE_DATA | ACL_APPEND_DATA);
 634                                         previous->ae_perm &=
 635                                             ~(ACL_WRITE_DATA | ACL_APPEND_DATA);
 636                                 }
 637
 638                                 if (extramode & EXEC) {
 639                                         entry->ae_perm &= ~ACL_EXECUTE;
 640                                         previous->ae_perm &= ~ACL_EXECUTE;
 641                                 }
 642                         }
 643                 }
 644         }
 645
 646         /*
 647          * 2. If there at least six ACEs, the final six ACEs are examined.
 648          *    If they are not equal to what we want, append six ACEs.
 649          */
 650         must_append = 0;
 651         if (aclp->acl_cnt < 6) {
 652                 must_append = 1;
 653         } else {
 654                 a6 = &(aclp->acl_entry[aclp->acl_cnt - 1]);
 655                 a5 = &(aclp->acl_entry[aclp->acl_cnt - 2]);
 656                 a4 = &(aclp->acl_entry[aclp->acl_cnt - 3]);
 657                 a3 = &(aclp->acl_entry[aclp->acl_cnt - 4]);
 658                 a2 = &(aclp->acl_entry[aclp->acl_cnt - 5]);
 659                 a1 = &(aclp->acl_entry[aclp->acl_cnt - 6]);
 660
 661                 if (!_acl_entry_matches(a1, ACL_USER_OBJ, 0,
 662                     ACL_ENTRY_TYPE_DENY))
 663                         must_append = 1;
 664                 if (!_acl_entry_matches(a2, ACL_USER_OBJ, ACL_WRITE_ACL |
 665                     ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
 666                     ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_ALLOW))
 667                         must_append = 1;
 668                 if (!_acl_entry_matches(a3, ACL_GROUP_OBJ, 0,
 669                     ACL_ENTRY_TYPE_DENY))
 670                         must_append = 1;
 671                 if (!_acl_entry_matches(a4, ACL_GROUP_OBJ, 0,
 672                     ACL_ENTRY_TYPE_ALLOW))
 673                         must_append = 1;
 674                 if (!_acl_entry_matches(a5, ACL_EVERYONE, ACL_WRITE_ACL |
 675                     ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
 676                     ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_DENY))
 677                         must_append = 1;
 678                 if (!_acl_entry_matches(a6, ACL_EVERYONE, ACL_READ_ACL |
 679                     ACL_READ_ATTRIBUTES | ACL_READ_NAMED_ATTRS |
 680                     ACL_SYNCHRONIZE, ACL_ENTRY_TYPE_ALLOW))
 681                         must_append = 1;
 682         }
 683
 684         if (must_append) {
 685                 KASSERT(aclp->acl_cnt + 6 <= ACL_MAX_ENTRIES,
 686                     ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
 687
 688                 a1 = _acl_append(aclp, ACL_USER_OBJ, 0, ACL_ENTRY_TYPE_DENY);
 689                 a2 = _acl_append(aclp, ACL_USER_OBJ, ACL_WRITE_ACL |
 690                     ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
 691                     ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_ALLOW);
 692                 a3 = _acl_append(aclp, ACL_GROUP_OBJ, 0, ACL_ENTRY_TYPE_DENY);
 693                 a4 = _acl_append(aclp, ACL_GROUP_OBJ, 0, ACL_ENTRY_TYPE_ALLOW);
 694                 a5 = _acl_append(aclp, ACL_EVERYONE, ACL_WRITE_ACL |
 695                     ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
 696                     ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_DENY);
 697                 a6 = _acl_append(aclp, ACL_EVERYONE, ACL_READ_ACL |
 698                     ACL_READ_ATTRIBUTES | ACL_READ_NAMED_ATTRS |
 699                     ACL_SYNCHRONIZE, ACL_ENTRY_TYPE_ALLOW);
 700
 701                 KASSERT(a1 != NULL && a2 != NULL && a3 != NULL && a4 != NULL &&
 702                     a5 != NULL && a6 != NULL, ("couldn't append to ACL."));
 703         }
 704
 705         /*
 706          * 3. The final six ACEs are adjusted according to the incoming mode.
 707          */
 708         if (mode & S_IRUSR)
 709                 a2->ae_perm |= ACL_READ_DATA;
 710         else
 711                 a1->ae_perm |= ACL_READ_DATA;
 712         if (mode & S_IWUSR)
 713                 a2->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
 714         else
 715                 a1->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
 716         if (mode & S_IXUSR)
 717                 a2->ae_perm |= ACL_EXECUTE;
 718         else
 719                 a1->ae_perm |= ACL_EXECUTE;
 720
 721         if (mode & S_IRGRP)
 722                 a4->ae_perm |= ACL_READ_DATA;
 723         else
 724                 a3->ae_perm |= ACL_READ_DATA;
 725         if (mode & S_IWGRP)
 726                 a4->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
 727         else
 728                 a3->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
 729         if (mode & S_IXGRP)
 730                 a4->ae_perm |= ACL_EXECUTE;
 731         else
 732                 a3->ae_perm |= ACL_EXECUTE;
 733
 734         if (mode & S_IROTH)
 735                 a6->ae_perm |= ACL_READ_DATA;
 736         else
 737                 a5->ae_perm |= ACL_READ_DATA;
 738         if (mode & S_IWOTH)
 739                 a6->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
 740         else
 741                 a5->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
 742         if (mode & S_IXOTH)
 743                 a6->ae_perm |= ACL_EXECUTE;
 744         else
 745                 a5->ae_perm |= ACL_EXECUTE;
 746 }
 747
 748 void
 749 acl_nfs4_sync_mode_from_acl(mode_t *_mode, const struct acl *aclp)
 750 {
 751         int i;
 752         mode_t old_mode = *_mode, mode = 0, seen = 0;
 753         const struct acl_entry *entry;
 754
 755         KASSERT(aclp->acl_cnt > 0, ("aclp->acl_cnt > 0"));
 756         KASSERT(aclp->acl_cnt <= ACL_MAX_ENTRIES,
 757             ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
 758
 759         /*
 760          * NFSv4 Minor Version 1, draft-ietf-nfsv4-minorversion1-03.txt
 761          *
 762          * 3.16.6.1. Recomputing mode upon SETATTR of ACL
 763          */
 764
 765         for (i = 0; i < aclp->acl_cnt; i++) {
 766                 entry = &(aclp->acl_entry[i]);
 767
 768                 if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
 769                     entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
 770                         continue;
 771
 772                 if (entry->ae_flags & ACL_ENTRY_INHERIT_ONLY)
 773                         continue;
 774
 775                 if (entry->ae_tag == ACL_USER_OBJ) {
 776                         if ((entry->ae_perm & ACL_READ_DATA) &&
 777                             ((seen & S_IRUSR) == 0)) {
 778                                 seen |= S_IRUSR;
 779                                 if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 780                                         mode |= S_IRUSR;
 781                         }
 782                         if ((entry->ae_perm & ACL_WRITE_DATA) &&
 783                              ((seen & S_IWUSR) == 0)) {
 784                                 seen |= S_IWUSR;
 785                                 if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 786                                         mode |= S_IWUSR;
 787                         }
 788                         if ((entry->ae_perm & ACL_EXECUTE) &&
 789                             ((seen & S_IXUSR) == 0)) {
 790                                 seen |= S_IXUSR;
 791                                 if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 792                                         mode |= S_IXUSR;
 793                         }
 794                 } else if (entry->ae_tag == ACL_GROUP_OBJ) {
 795                         if ((entry->ae_perm & ACL_READ_DATA) &&
 796                             ((seen & S_IRGRP) == 0)) {
 797                                 seen |= S_IRGRP;
 798                                 if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 799                                         mode |= S_IRGRP;
 800                         }
 801                         if ((entry->ae_perm & ACL_WRITE_DATA) &&
 802                             ((seen & S_IWGRP) == 0)) {
 803                                 seen |= S_IWGRP;
 804                                 if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 805                                         mode |= S_IWGRP;
 806                         }
 807                         if ((entry->ae_perm & ACL_EXECUTE) &&
 808                             ((seen & S_IXGRP) == 0)) {
 809                                 seen |= S_IXGRP;
 810                                 if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 811                                         mode |= S_IXGRP;
 812                         }
 813                 } else if (entry->ae_tag == ACL_EVERYONE) {
 814                         if (entry->ae_perm & ACL_READ_DATA) {
 815                                 if ((seen & S_IRUSR) == 0) {
 816                                         seen |= S_IRUSR;
 817                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 818                                                 mode |= S_IRUSR;
 819                                 }
 820                                 if ((seen & S_IRGRP) == 0) {
 821                                         seen |= S_IRGRP;
 822                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 823                                                 mode |= S_IRGRP;
 824                                 }
 825                                 if ((seen & S_IROTH) == 0) {
 826                                         seen |= S_IROTH;
 827                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 828                                                 mode |= S_IROTH;
 829                                 }
 830                         }
 831                         if (entry->ae_perm & ACL_WRITE_DATA) {
 832                                 if ((seen & S_IWUSR) == 0) {
 833                                         seen |= S_IWUSR;
 834                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 835                                                 mode |= S_IWUSR;
 836                                 }
 837                                 if ((seen & S_IWGRP) == 0) {
 838                                         seen |= S_IWGRP;
 839                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 840                                                 mode |= S_IWGRP;
 841                                 }
 842                                 if ((seen & S_IWOTH) == 0) {
 843                                         seen |= S_IWOTH;
 844                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 845                                                 mode |= S_IWOTH;
 846                                 }
 847                         }
 848                         if (entry->ae_perm & ACL_EXECUTE) {
 849                                 if ((seen & S_IXUSR) == 0) {
 850                                         seen |= S_IXUSR;
 851                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 852                                                 mode |= S_IXUSR;
 853                                 }
 854                                 if ((seen & S_IXGRP) == 0) {
 855                                         seen |= S_IXGRP;
 856                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 857                                                 mode |= S_IXGRP;
 858                                 }
 859                                 if ((seen & S_IXOTH) == 0) {
 860                                         seen |= S_IXOTH;
 861                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 862                                                 mode |= S_IXOTH;
 863                                 }
 864                         }
 865                 }
 866         }
 867
 868         *_mode = mode | (old_mode & ACL_PRESERVE_MASK);
 869 }
 870
 871 void
 872 acl_nfs4_compute_inherited_acl(const struct acl *parent_aclp,
 873     struct acl *child_aclp, mode_t mode, int file_owner_id,
 874     int is_directory)
 875 {
 876         int i, flags;
 877         const struct acl_entry *parent_entry;
 878         struct acl_entry *entry, *copy;
 879
 880         KASSERT(child_aclp->acl_cnt == 0, ("child_aclp->acl_cnt == 0"));
 881         KASSERT(parent_aclp->acl_cnt > 0, ("parent_aclp->acl_cnt > 0"));
 882         KASSERT(parent_aclp->acl_cnt <= ACL_MAX_ENTRIES,
 883             ("parent_aclp->acl_cnt <= ACL_MAX_ENTRIES"));
 884
 885         /*
 886          * NFSv4 Minor Version 1, draft-ietf-nfsv4-minorversion1-03.txt
 887          *
 888          * 3.16.6.2. Applying the mode given to CREATE or OPEN
 889          *           to an inherited ACL
 890          */
 891
 892         /*
 893          * 1. Form an ACL that is the concatenation of all inheritable ACEs.
 894          */
 895         for (i = 0; i < parent_aclp->acl_cnt; i++) {
 896                 parent_entry = &(parent_aclp->acl_entry[i]);
 897                 flags = parent_entry->ae_flags;
 898
 899                 /*
 900                  * Entry is not inheritable at all.
 901                  */
 902                 if ((flags & (ACL_ENTRY_DIRECTORY_INHERIT |
 903                     ACL_ENTRY_FILE_INHERIT)) == 0)
 904                         continue;
 905
 906                 /*
 907                  * We're creating a file, but entry is not inheritable
 908                  * by files.
 909                  */
 910                 if (!is_directory && (flags & ACL_ENTRY_FILE_INHERIT) == 0)
 911                         continue;
 912
 913                 /*
 914                  * Entry is inheritable only by files, but has NO_PROPAGATE
 915                  * flag set, and we're creating a directory, so it wouldn't
 916                  * propagate to any file in that directory anyway.
 917                  */
 918                 if (is_directory &&
 919                     (flags & ACL_ENTRY_DIRECTORY_INHERIT) == 0 &&
 920                     (flags & ACL_ENTRY_NO_PROPAGATE_INHERIT))
 921                         continue;
 922
 923                 KASSERT(child_aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES,
 924                     ("child_aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES"));
 925                 child_aclp->acl_entry[child_aclp->acl_cnt] = *parent_entry;
 926                 child_aclp->acl_cnt++;
 927         }
 928
 929         /*
 930          * 2. For each entry in the new ACL, adjust its flags, possibly
 931          *    creating two entries in place of one.
 932          */
 933         for (i = 0; i < child_aclp->acl_cnt; i++) {
 934                 entry = &(child_aclp->acl_entry[i]);
 935
 936                 /*
 937                  * This is not in the specification, but SunOS
 938                  * apparently does that.
 939                  */
 940                 if (((entry->ae_flags & ACL_ENTRY_NO_PROPAGATE_INHERIT) ||
 941                     !is_directory) &&
 942                     entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 943                         entry->ae_perm &= ~(ACL_WRITE_ACL | ACL_WRITE_OWNER);
 944
 945                 /*
 946                  * 2.A. If the ACL_ENTRY_NO_PROPAGATE_INHERIT is set, or if the object
 947                  *      being created is not a directory, then clear the
 948                  *      following flags: ACL_ENTRY_NO_PROPAGATE_INHERIT,
 949                  *      ACL_ENTRY_FILE_INHERIT, ACL_ENTRY_DIRECTORY_INHERIT,
 950                  *      ACL_ENTRY_INHERIT_ONLY.
 951                  */
 952                 if (entry->ae_flags & ACL_ENTRY_NO_PROPAGATE_INHERIT ||
 953                     !is_directory) {
 954                         entry->ae_flags &= ~(ACL_ENTRY_NO_PROPAGATE_INHERIT |
 955                         ACL_ENTRY_FILE_INHERIT | ACL_ENTRY_DIRECTORY_INHERIT |
 956                         ACL_ENTRY_INHERIT_ONLY);
 957
 958                         /*
 959                          * Continue on to the next ACE.
 960                          */
 961                         continue;
 962                 }
 963
 964                 /*
 965                  * 2.B. If the object is a directory and ACL_ENTRY_FILE_INHERIT
 966                  *      is set, but ACL_ENTRY_NO_PROPAGATE_INHERIT is not set, ensure
 967                  *      that ACL_ENTRY_INHERIT_ONLY is set.  Continue to the
 968                  *      next ACE.  Otherwise...
 969                  */
 970                 /*
 971                  * XXX: Read it again and make sure what does the "otherwise"
 972                  *      apply to.
 973                  */
 974                 if (is_directory &&
 975                     (entry->ae_flags & ACL_ENTRY_FILE_INHERIT) &&
 976                     ((entry->ae_flags & ACL_ENTRY_DIRECTORY_INHERIT) == 0)) {
 977                         entry->ae_flags |= ACL_ENTRY_INHERIT_ONLY;
 978                         continue;
 979                 }
 980
 981                 /*
 982                  * 2.C. If the type of the ACE is neither ALLOW nor deny,
 983                  *      then continue.
 984                  */
 985                 if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
 986                     entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
 987                         continue;
 988
 989                 /*
 990                  * 2.D. Copy the original ACE into a second, adjacent ACE.
 991                  */
 992                 copy = _acl_duplicate_entry(child_aclp, i);
 993
 994                 /*
 995                  * 2.E. On the first ACE, ensure that ACL_ENTRY_INHERIT_ONLY
 996                  *      is set.
 997                  */
 998                 entry->ae_flags |= ACL_ENTRY_INHERIT_ONLY;
 999
1000                 /*
1001                  * 2.F. On the second ACE, clear the following flags:
1002                  *      ACL_ENTRY_NO_PROPAGATE_INHERIT, ACL_ENTRY_FILE_INHERIT,
1003                  *      ACL_ENTRY_DIRECTORY_INHERIT, ACL_ENTRY_INHERIT_ONLY.
1004                  */
1005                 copy->ae_flags &= ~(ACL_ENTRY_NO_PROPAGATE_INHERIT |
1006                     ACL_ENTRY_FILE_INHERIT | ACL_ENTRY_DIRECTORY_INHERIT |
1007                     ACL_ENTRY_INHERIT_ONLY);
1008
1009                 /*
1010                  * 2.G. On the second ACE, if the type is ALLOW,
1011                  *      an implementation MAY clear the following
1012                  *      mask bits: ACL_WRITE_ACL, ACL_WRITE_OWNER.
1013                  */
1014                 if (copy->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
1015                         copy->ae_perm &= ~(ACL_WRITE_ACL | ACL_WRITE_OWNER);
1016
1017                 /*
1018                  * Increment the counter to skip the copied entry.
1019                  */
1020                 i++;
1021         }
1022
1023         /*
1024          * 3. To ensure that the mode is honored, apply the algorithm describe
1025          *    in Section 2.16.6.3, using the mode that is to be used for file
1026          *    creation.
1027          */
1028         acl_nfs4_sync_acl_from_mode(child_aclp, mode, file_owner_id);
1029 }
1030
1031 #ifdef _KERNEL
1032 static int
1033 _acls_are_equal(const struct acl *a, const struct acl *b)
1034 {
1035         int i;
1036         const struct acl_entry *entrya, *entryb;
1037
1038         if (a->acl_cnt != b->acl_cnt)
1039                 return (0);
1040
1041         for (i = 0; i < b->acl_cnt; i++) {
1042                 entrya = &(a->acl_entry[i]);
1043                 entryb = &(b->acl_entry[i]);
1044
1045                 if (entrya->ae_tag != entryb->ae_tag ||
1046                     entrya->ae_id != entryb->ae_id ||
1047                     entrya->ae_perm != entryb->ae_perm ||
1048                     entrya->ae_entry_type != entryb->ae_entry_type ||
1049                     entrya->ae_flags != entryb->ae_flags)
1050                         return (0);
1051         }
1052
1053         return (1);
1054 }
1055
1056 /*
1057  * This routine is used to determine whether to remove entry_type attribute
1058  * that stores ACL contents.
1059  */
1060 int
1061 acl_nfs4_is_trivial(const struct acl *aclp, int file_owner_id)
1062 {
1063         int trivial;
1064         mode_t tmpmode = 0;
1065         struct acl *tmpaclp;
1066
1067         if (aclp->acl_cnt != 6)
1068                 return (0);
1069
1070         /*
1071          * Compute the mode from the ACL, then compute new ACL from that mode.
1072          * If the ACLs are identical, then the ACL is trivial.
1073          *
1074          * XXX: I guess there is a faster way to do this.  However, even
1075          *      this slow implementation significantly speeds things up
1076          *      for files that don't have any entry_type ACL entries - it's
1077          *      critical for performance to not use EA when they are not
1078          *      needed.
1079          */
1080         tmpaclp = acl_alloc(M_WAITOK | M_ZERO);
1081         acl_nfs4_sync_mode_from_acl(&tmpmode, aclp);
1082         acl_nfs4_sync_acl_from_mode(tmpaclp, tmpmode, file_owner_id);
1083         trivial = _acls_are_equal(aclp, tmpaclp);
1084         acl_free(tmpaclp);
1085
1086         return (trivial);
1087 }
1088 #endif /* _KERNEL */
1089
1090 int
1091 acl_nfs4_check(const struct acl *aclp, int is_directory)
1092 {
1093         int i;
1094         const struct acl_entry *entry;
1095
1096         /*
1097          * The spec doesn't seem to say anything about ACL validity.
1098          * It seems there is not much to do here.  There is even no need
1099          * to count "owner@" or "everyone@" (ACL_USER_OBJ and ACL_EVERYONE)
1100          * entries, as there can be several of them and that's perfectly
1101          * valid.  There can be none of them too.  Really.
1102          */
1103
1104         if (aclp->acl_cnt > ACL_MAX_ENTRIES || aclp->acl_cnt <= 0)
1105                 return (EINVAL);
1106
1107         for (i = 0; i < aclp->acl_cnt; i++) {
1108                 entry = &(aclp->acl_entry[i]);
1109
1110                 switch (entry->ae_tag) {
1111                 case ACL_USER_OBJ:
1112                 case ACL_GROUP_OBJ:
1113                 case ACL_EVERYONE:
1114                         if (entry->ae_id != ACL_UNDEFINED_ID)
1115                                 return (EINVAL);
1116                         break;
1117
1118                 case ACL_USER:
1119                 case ACL_GROUP:
1120                         if (entry->ae_id == ACL_UNDEFINED_ID)
1121                                 return (EINVAL);
1122                         break;
1123
1124                 default:
1125                         return (EINVAL);
1126                 }
1127
1128                 if ((entry->ae_perm | ACL_NFS4_PERM_BITS) != ACL_NFS4_PERM_BITS)
1129                         return (EINVAL);
1130
1131                 /*
1132                  * Disallow ACL_ENTRY_TYPE_AUDIT and ACL_ENTRY_TYPE_ALARM for now.
1133                  */
1134                 if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
1135                     entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
1136                         return (EINVAL);
1137
1138                 if ((entry->ae_flags | ACL_FLAGS_BITS) != ACL_FLAGS_BITS)
1139                         return (EINVAL);
1140
1141                 /* Disallow unimplemented flags. */
1142                 if (entry->ae_flags & (ACL_ENTRY_SUCCESSFUL_ACCESS |
1143                     ACL_ENTRY_FAILED_ACCESS))
1144                         return (EINVAL);
1145
1146                 /* Disallow flags not allowed for ordinary files. */
1147                 if (!is_directory) {
1148                         if (entry->ae_flags & (ACL_ENTRY_FILE_INHERIT |
1149                             ACL_ENTRY_DIRECTORY_INHERIT |
1150                             ACL_ENTRY_NO_PROPAGATE_INHERIT | ACL_ENTRY_INHERIT_ONLY))
1151                                 return (EINVAL);
1152                 }
1153         }
1154
1155         return (0);
1156 }