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 void
 327 acl_nfs4_sync_acl_from_mode(struct acl *aclp, mode_t mode, int file_owner_id)
 328 {
 329         int i, meets, must_append;
 330         struct acl_entry *entry, *copy, *previous,
 331             *a1, *a2, *a3, *a4, *a5, *a6;
 332         mode_t amode;
 333         const int READ = 04;
 334         const int WRITE = 02;
 335         const int EXEC = 01;
 336
 337         KASSERT(aclp->acl_cnt >= 0, ("aclp->acl_cnt >= 0"));
 338         KASSERT(aclp->acl_cnt <= ACL_MAX_ENTRIES,
 339             ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
 340
 341         /*
 342          * NFSv4 Minor Version 1, draft-ietf-nfsv4-minorversion1-03.txt
 343          *
 344          * 3.16.6.3. Applying a Mode to an Existing ACL
 345          */
 346
 347         /*
 348          * 1. For each ACE:
 349          */
 350         for (i = 0; i < aclp->acl_cnt; i++) {
 351                 entry = &(aclp->acl_entry[i]);
 352
 353                 /*
 354                  * 1.1. If the type is neither ALLOW or DENY - skip.
 355                  */
 356                 if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
 357                     entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
 358                         continue;
 359
 360                 /*
 361                  * 1.2. If ACL_ENTRY_INHERIT_ONLY is set - skip.
 362                  */
 363                 if (entry->ae_flags & ACL_ENTRY_INHERIT_ONLY)
 364                         continue;
 365
 366                 /*
 367                  * 1.3. If ACL_ENTRY_FILE_INHERIT or ACL_ENTRY_DIRECTORY_INHERIT
 368                  *      are set:
 369                  */
 370                 if (entry->ae_flags &
 371                     (ACL_ENTRY_FILE_INHERIT | ACL_ENTRY_DIRECTORY_INHERIT)) {
 372                         /*
 373                          * 1.3.1. A copy of the current ACE is made, and placed
 374                          *        in the ACL immediately following the current
 375                          *        ACE.
 376                          */
 377                         copy = _acl_duplicate_entry(aclp, i);
 378
 379                         /*
 380                          * 1.3.2. In the first ACE, the flag
 381                          *        ACL_ENTRY_INHERIT_ONLY is set.
 382                          */
 383                         entry->ae_flags |= ACL_ENTRY_INHERIT_ONLY;
 384
 385                         /*
 386                          * 1.3.3. In the second ACE, the following flags
 387                          *        are cleared:
 388                          *        ACL_ENTRY_FILE_INHERIT,
 389                          *        ACL_ENTRY_DIRECTORY_INHERIT,
 390                          *        ACL_ENTRY_NO_PROPAGATE_INHERIT.
 391                          */
 392                         copy->ae_flags &= ~(ACL_ENTRY_FILE_INHERIT |
 393                             ACL_ENTRY_DIRECTORY_INHERIT |
 394                             ACL_ENTRY_NO_PROPAGATE_INHERIT);
 395
 396                         /*
 397                          * The algorithm continues on with the second ACE.
 398                          */
 399                         i++;
 400                         entry = copy;
 401                 }
 402
 403                 /*
 404                  * 1.4. If it's owner@, group@ or everyone@ entry, clear
 405                  *      ACL_READ_DATA, ACL_WRITE_DATA, ACL_APPEND_DATA
 406                  *      and ACL_EXECUTE.  Continue to the next entry.
 407                  */
 408                 if (entry->ae_tag == ACL_USER_OBJ ||
 409                     entry->ae_tag == ACL_GROUP_OBJ ||
 410                     entry->ae_tag == ACL_EVERYONE) {
 411                         entry->ae_perm &= ~(ACL_READ_DATA | ACL_WRITE_DATA |
 412                             ACL_APPEND_DATA | ACL_EXECUTE);
 413                         continue;
 414                 }
 415
 416                 /*
 417                  * 1.5. Otherwise, if the "who" field did not match one
 418                  *      of OWNER@, GROUP@, EVERYONE@:
 419                  *
 420                  * 1.5.1. If the type is ALLOW, check the preceding ACE.
 421                  *        If it does not meet all of the following criteria:
 422                  */
 423                 if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW)
 424                         continue;
 425
 426                 meets = 0;
 427                 if (i > 0) {
 428                         meets = 1;
 429                         previous = &(aclp->acl_entry[i - 1]);
 430
 431                         /*
 432                          * 1.5.1.1. The type field is DENY,
 433                          */
 434                         if (previous->ae_entry_type != ACL_ENTRY_TYPE_DENY)
 435                                 meets = 0;
 436
 437                         /*
 438                          * 1.5.1.2. The "who" field is the same as the current
 439                          *          ACE,
 440                          *
 441                          * 1.5.1.3. The flag bit ACE4_IDENTIFIER_GROUP
 442                          *          is the same as it is in the current ACE,
 443                          *          and no other flag bits are set,
 444                          */
 445                         if (previous->ae_id != entry->ae_id ||
 446                             previous->ae_tag != entry->ae_tag)
 447                                 meets = 0;
 448
 449                         if (previous->ae_flags)
 450                                 meets = 0;
 451
 452                         /*
 453                          * 1.5.1.4. The mask bits are a subset of the mask bits
 454                          *          of the current ACE, and are also subset of
 455                          *          the following: ACL_READ_DATA,
 456                          *          ACL_WRITE_DATA, ACL_APPEND_DATA, ACL_EXECUTE
 457                          */
 458                         if (previous->ae_perm & ~(entry->ae_perm))
 459                                 meets = 0;
 460
 461                         if (previous->ae_perm & ~(ACL_READ_DATA |
 462                             ACL_WRITE_DATA | ACL_APPEND_DATA | ACL_EXECUTE))
 463                                 meets = 0;
 464                 }
 465
 466                 if (!meets) {
 467                         /*
 468                          * Then the ACE of type DENY, with a who equal
 469                          * to the current ACE, flag bits equal to
 470                          * (<current ACE flags> & <ACE_IDENTIFIER_GROUP>)
 471                          * and no mask bits, is prepended.
 472                          */
 473                         previous = entry;
 474                         entry = _acl_duplicate_entry(aclp, i);
 475
 476                         /* Adjust counter, as we've just added an entry. */
 477                         i++;
 478
 479                         previous->ae_tag = entry->ae_tag;
 480                         previous->ae_id = entry->ae_id;
 481                         previous->ae_flags = entry->ae_flags;
 482                         previous->ae_perm = 0;
 483                         previous->ae_entry_type = ACL_ENTRY_TYPE_DENY;
 484                 }
 485
 486                 /*
 487                  * 1.5.2. The following modifications are made to the prepended
 488                  *        ACE.  The intent is to mask the following ACE
 489                  *        to disallow ACL_READ_DATA, ACL_WRITE_DATA,
 490                  *        ACL_APPEND_DATA, or ACL_EXECUTE, based upon the group
 491                  *        permissions of the new mode.  As a special case,
 492                  *        if the ACE matches the current owner of the file,
 493                  *        the owner bits are used, rather than the group bits.
 494                  *        This is reflected in the algorithm below.
 495                  */
 496                 amode = mode >> 3;
 497
 498                 /*
 499                  * If ACE4_IDENTIFIER_GROUP is not set, and the "who" field
 500                  * in ACE matches the owner of the file, we shift amode three
 501                  * more bits, in order to have the owner permission bits
 502                  * placed in the three low order bits of amode.
 503                  */
 504                 if (entry->ae_tag == ACL_USER && entry->ae_id == file_owner_id)
 505                         amode = amode >> 3;
 506
 507                 if (entry->ae_perm & ACL_READ_DATA) {
 508                         if (amode & READ)
 509                                 previous->ae_perm &= ~ACL_READ_DATA;
 510                         else
 511                                 previous->ae_perm |= ACL_READ_DATA;
 512                 }
 513
 514                 if (entry->ae_perm & ACL_WRITE_DATA) {
 515                         if (amode & WRITE)
 516                                 previous->ae_perm &= ~ACL_WRITE_DATA;
 517                         else
 518                                 previous->ae_perm |= ACL_WRITE_DATA;
 519                 }
 520
 521                 if (entry->ae_perm & ACL_APPEND_DATA) {
 522                         if (amode & WRITE)
 523                                 previous->ae_perm &= ~ACL_APPEND_DATA;
 524                         else
 525                                 previous->ae_perm |= ACL_APPEND_DATA;
 526                 }
 527
 528                 if (entry->ae_perm & ACL_EXECUTE) {
 529                         if (amode & EXEC)
 530                                 previous->ae_perm &= ~ACL_EXECUTE;
 531                         else
 532                                 previous->ae_perm |= ACL_EXECUTE;
 533                 }
 534
 535                 /*
 536                  * 1.5.3. If ACE4_IDENTIFIER_GROUP is set in the flags
 537                  *        of the ALLOW ace:
 538                  *
 539                  * XXX: This point is not there in the Falkner's draft.
 540                  */
 541                 if (entry->ae_tag == ACL_GROUP &&
 542                     entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW) {
 543                         mode_t extramode, ownermode;
 544                         extramode = (mode >> 3) & 07;
 545                         ownermode = mode >> 6;
 546                         extramode &= ~ownermode;
 547
 548                         if (extramode) {
 549                                 if (extramode & READ) {
 550                                         entry->ae_perm &= ~ACL_READ_DATA;
 551                                         previous->ae_perm &= ~ACL_READ_DATA;
 552                                 }
 553
 554                                 if (extramode & WRITE) {
 555                                         entry->ae_perm &=
 556                                             ~(ACL_WRITE_DATA | ACL_APPEND_DATA);
 557                                         previous->ae_perm &=
 558                                             ~(ACL_WRITE_DATA | ACL_APPEND_DATA);
 559                                 }
 560
 561                                 if (extramode & EXEC) {
 562                                         entry->ae_perm &= ~ACL_EXECUTE;
 563                                         previous->ae_perm &= ~ACL_EXECUTE;
 564                                 }
 565                         }
 566                 }
 567         }
 568
 569         /*
 570          * 2. If there at least six ACEs, the final six ACEs are examined.
 571          *    If they are not equal to what we want, append six ACEs.
 572          */
 573         must_append = 0;
 574         if (aclp->acl_cnt < 6) {
 575                 must_append = 1;
 576         } else {
 577                 a6 = &(aclp->acl_entry[aclp->acl_cnt - 1]);
 578                 a5 = &(aclp->acl_entry[aclp->acl_cnt - 2]);
 579                 a4 = &(aclp->acl_entry[aclp->acl_cnt - 3]);
 580                 a3 = &(aclp->acl_entry[aclp->acl_cnt - 4]);
 581                 a2 = &(aclp->acl_entry[aclp->acl_cnt - 5]);
 582                 a1 = &(aclp->acl_entry[aclp->acl_cnt - 6]);
 583
 584                 if (!_acl_entry_matches(a1, ACL_USER_OBJ, 0,
 585                     ACL_ENTRY_TYPE_DENY))
 586                         must_append = 1;
 587                 if (!_acl_entry_matches(a2, ACL_USER_OBJ, ACL_WRITE_ACL |
 588                     ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
 589                     ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_ALLOW))
 590                         must_append = 1;
 591                 if (!_acl_entry_matches(a3, ACL_GROUP_OBJ, 0,
 592                     ACL_ENTRY_TYPE_DENY))
 593                         must_append = 1;
 594                 if (!_acl_entry_matches(a4, ACL_GROUP_OBJ, 0,
 595                     ACL_ENTRY_TYPE_ALLOW))
 596                         must_append = 1;
 597                 if (!_acl_entry_matches(a5, ACL_EVERYONE, ACL_WRITE_ACL |
 598                     ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
 599                     ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_DENY))
 600                         must_append = 1;
 601                 if (!_acl_entry_matches(a6, ACL_EVERYONE, ACL_READ_ACL |
 602                     ACL_READ_ATTRIBUTES | ACL_READ_NAMED_ATTRS |
 603                     ACL_SYNCHRONIZE, ACL_ENTRY_TYPE_ALLOW))
 604                         must_append = 1;
 605         }
 606
 607         if (must_append) {
 608                 KASSERT(aclp->acl_cnt + 6 <= ACL_MAX_ENTRIES,
 609                     ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
 610
 611                 a1 = _acl_append(aclp, ACL_USER_OBJ, 0, ACL_ENTRY_TYPE_DENY);
 612                 a2 = _acl_append(aclp, ACL_USER_OBJ, ACL_WRITE_ACL |
 613                     ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
 614                     ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_ALLOW);
 615                 a3 = _acl_append(aclp, ACL_GROUP_OBJ, 0, ACL_ENTRY_TYPE_DENY);
 616                 a4 = _acl_append(aclp, ACL_GROUP_OBJ, 0, ACL_ENTRY_TYPE_ALLOW);
 617                 a5 = _acl_append(aclp, ACL_EVERYONE, ACL_WRITE_ACL |
 618                     ACL_WRITE_OWNER | ACL_WRITE_ATTRIBUTES |
 619                     ACL_WRITE_NAMED_ATTRS, ACL_ENTRY_TYPE_DENY);
 620                 a6 = _acl_append(aclp, ACL_EVERYONE, ACL_READ_ACL |
 621                     ACL_READ_ATTRIBUTES | ACL_READ_NAMED_ATTRS |
 622                     ACL_SYNCHRONIZE, ACL_ENTRY_TYPE_ALLOW);
 623
 624                 KASSERT(a1 != NULL && a2 != NULL && a3 != NULL && a4 != NULL &&
 625                     a5 != NULL && a6 != NULL, ("couldn't append to ACL."));
 626         }
 627
 628         /*
 629          * 3. The final six ACEs are adjusted according to the incoming mode.
 630          */
 631         if (mode & S_IRUSR)
 632                 a2->ae_perm |= ACL_READ_DATA;
 633         else
 634                 a1->ae_perm |= ACL_READ_DATA;
 635         if (mode & S_IWUSR)
 636                 a2->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
 637         else
 638                 a1->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
 639         if (mode & S_IXUSR)
 640                 a2->ae_perm |= ACL_EXECUTE;
 641         else
 642                 a1->ae_perm |= ACL_EXECUTE;
 643
 644         if (mode & S_IRGRP)
 645                 a4->ae_perm |= ACL_READ_DATA;
 646         else
 647                 a3->ae_perm |= ACL_READ_DATA;
 648         if (mode & S_IWGRP)
 649                 a4->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
 650         else
 651                 a3->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
 652         if (mode & S_IXGRP)
 653                 a4->ae_perm |= ACL_EXECUTE;
 654         else
 655                 a3->ae_perm |= ACL_EXECUTE;
 656
 657         if (mode & S_IROTH)
 658                 a6->ae_perm |= ACL_READ_DATA;
 659         else
 660                 a5->ae_perm |= ACL_READ_DATA;
 661         if (mode & S_IWOTH)
 662                 a6->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
 663         else
 664                 a5->ae_perm |= (ACL_WRITE_DATA | ACL_APPEND_DATA);
 665         if (mode & S_IXOTH)
 666                 a6->ae_perm |= ACL_EXECUTE;
 667         else
 668                 a5->ae_perm |= ACL_EXECUTE;
 669 }
 670
 671 void
 672 acl_nfs4_sync_mode_from_acl(mode_t *_mode, const struct acl *aclp)
 673 {
 674         int i;
 675         mode_t old_mode = *_mode, mode = 0, seen = 0;
 676         const struct acl_entry *entry;
 677
 678         KASSERT(aclp->acl_cnt > 0, ("aclp->acl_cnt > 0"));
 679         KASSERT(aclp->acl_cnt <= ACL_MAX_ENTRIES,
 680             ("aclp->acl_cnt <= ACL_MAX_ENTRIES"));
 681
 682         /*
 683          * NFSv4 Minor Version 1, draft-ietf-nfsv4-minorversion1-03.txt
 684          *
 685          * 3.16.6.1. Recomputing mode upon SETATTR of ACL
 686          */
 687
 688         for (i = 0; i < aclp->acl_cnt; i++) {
 689                 entry = &(aclp->acl_entry[i]);
 690
 691                 if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
 692                     entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
 693                         continue;
 694
 695                 if (entry->ae_flags & ACL_ENTRY_INHERIT_ONLY)
 696                         continue;
 697
 698                 if (entry->ae_tag == ACL_USER_OBJ) {
 699                         if ((entry->ae_perm & ACL_READ_DATA) &&
 700                             ((seen & S_IRUSR) == 0)) {
 701                                 seen |= S_IRUSR;
 702                                 if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 703                                         mode |= S_IRUSR;
 704                         }
 705                         if ((entry->ae_perm & ACL_WRITE_DATA) &&
 706                              ((seen & S_IWUSR) == 0)) {
 707                                 seen |= S_IWUSR;
 708                                 if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 709                                         mode |= S_IWUSR;
 710                         }
 711                         if ((entry->ae_perm & ACL_EXECUTE) &&
 712                             ((seen & S_IXUSR) == 0)) {
 713                                 seen |= S_IXUSR;
 714                                 if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 715                                         mode |= S_IXUSR;
 716                         }
 717                 } else if (entry->ae_tag == ACL_GROUP_OBJ) {
 718                         if ((entry->ae_perm & ACL_READ_DATA) &&
 719                             ((seen & S_IRGRP) == 0)) {
 720                                 seen |= S_IRGRP;
 721                                 if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 722                                         mode |= S_IRGRP;
 723                         }
 724                         if ((entry->ae_perm & ACL_WRITE_DATA) &&
 725                             ((seen & S_IWGRP) == 0)) {
 726                                 seen |= S_IWGRP;
 727                                 if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 728                                         mode |= S_IWGRP;
 729                         }
 730                         if ((entry->ae_perm & ACL_EXECUTE) &&
 731                             ((seen & S_IXGRP) == 0)) {
 732                                 seen |= S_IXGRP;
 733                                 if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 734                                         mode |= S_IXGRP;
 735                         }
 736                 } else if (entry->ae_tag == ACL_EVERYONE) {
 737                         if (entry->ae_perm & ACL_READ_DATA) {
 738                                 if ((seen & S_IRUSR) == 0) {
 739                                         seen |= S_IRUSR;
 740                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 741                                                 mode |= S_IRUSR;
 742                                 }
 743                                 if ((seen & S_IRGRP) == 0) {
 744                                         seen |= S_IRGRP;
 745                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 746                                                 mode |= S_IRGRP;
 747                                 }
 748                                 if ((seen & S_IROTH) == 0) {
 749                                         seen |= S_IROTH;
 750                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 751                                                 mode |= S_IROTH;
 752                                 }
 753                         }
 754                         if (entry->ae_perm & ACL_WRITE_DATA) {
 755                                 if ((seen & S_IWUSR) == 0) {
 756                                         seen |= S_IWUSR;
 757                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 758                                                 mode |= S_IWUSR;
 759                                 }
 760                                 if ((seen & S_IWGRP) == 0) {
 761                                         seen |= S_IWGRP;
 762                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 763                                                 mode |= S_IWGRP;
 764                                 }
 765                                 if ((seen & S_IWOTH) == 0) {
 766                                         seen |= S_IWOTH;
 767                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 768                                                 mode |= S_IWOTH;
 769                                 }
 770                         }
 771                         if (entry->ae_perm & ACL_EXECUTE) {
 772                                 if ((seen & S_IXUSR) == 0) {
 773                                         seen |= S_IXUSR;
 774                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 775                                                 mode |= S_IXUSR;
 776                                 }
 777                                 if ((seen & S_IXGRP) == 0) {
 778                                         seen |= S_IXGRP;
 779                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 780                                                 mode |= S_IXGRP;
 781                                 }
 782                                 if ((seen & S_IXOTH) == 0) {
 783                                         seen |= S_IXOTH;
 784                                         if (entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 785                                                 mode |= S_IXOTH;
 786                                 }
 787                         }
 788                 }
 789         }
 790
 791         *_mode = mode | (old_mode & ACL_PRESERVE_MASK);
 792 }
 793
 794 void
 795 acl_nfs4_compute_inherited_acl(const struct acl *parent_aclp,
 796     struct acl *child_aclp, mode_t mode, int file_owner_id,
 797     int is_directory)
 798 {
 799         int i, flags;
 800         const struct acl_entry *parent_entry;
 801         struct acl_entry *entry, *copy;
 802
 803         KASSERT(child_aclp->acl_cnt == 0, ("child_aclp->acl_cnt == 0"));
 804         KASSERT(parent_aclp->acl_cnt > 0, ("parent_aclp->acl_cnt > 0"));
 805         KASSERT(parent_aclp->acl_cnt <= ACL_MAX_ENTRIES,
 806             ("parent_aclp->acl_cnt <= ACL_MAX_ENTRIES"));
 807
 808         /*
 809          * NFSv4 Minor Version 1, draft-ietf-nfsv4-minorversion1-03.txt
 810          *
 811          * 3.16.6.2. Applying the mode given to CREATE or OPEN
 812          *           to an inherited ACL
 813          */
 814
 815         /*
 816          * 1. Form an ACL that is the concatenation of all inheritable ACEs.
 817          */
 818         for (i = 0; i < parent_aclp->acl_cnt; i++) {
 819                 parent_entry = &(parent_aclp->acl_entry[i]);
 820                 flags = parent_entry->ae_flags;
 821
 822                 /*
 823                  * Entry is not inheritable at all.
 824                  */
 825                 if ((flags & (ACL_ENTRY_DIRECTORY_INHERIT |
 826                     ACL_ENTRY_FILE_INHERIT)) == 0)
 827                         continue;
 828
 829                 /*
 830                  * We're creating a file, but entry is not inheritable
 831                  * by files.
 832                  */
 833                 if (!is_directory && (flags & ACL_ENTRY_FILE_INHERIT) == 0)
 834                         continue;
 835
 836                 /*
 837                  * Entry is inheritable only by files, but has NO_PROPAGATE
 838                  * flag set, and we're creating a directory, so it wouldn't
 839                  * propagate to any file in that directory anyway.
 840                  */
 841                 if (is_directory &&
 842                     (flags & ACL_ENTRY_DIRECTORY_INHERIT) == 0 &&
 843                     (flags & ACL_ENTRY_NO_PROPAGATE_INHERIT))
 844                         continue;
 845
 846                 KASSERT(child_aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES,
 847                     ("child_aclp->acl_cnt + 1 <= ACL_MAX_ENTRIES"));
 848                 child_aclp->acl_entry[child_aclp->acl_cnt] = *parent_entry;
 849                 child_aclp->acl_cnt++;
 850         }
 851
 852         /*
 853          * 2. For each entry in the new ACL, adjust its flags, possibly
 854          *    creating two entries in place of one.
 855          */
 856         for (i = 0; i < child_aclp->acl_cnt; i++) {
 857                 entry = &(child_aclp->acl_entry[i]);
 858
 859                 /*
 860                  * This is not in the specification, but SunOS
 861                  * apparently does that.
 862                  */
 863                 if (((entry->ae_flags & ACL_ENTRY_NO_PROPAGATE_INHERIT) ||
 864                     !is_directory) &&
 865                     entry->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 866                         entry->ae_perm &= ~(ACL_WRITE_ACL | ACL_WRITE_OWNER);
 867
 868                 /*
 869                  * 2.A. If the ACL_ENTRY_NO_PROPAGATE_INHERIT is set, or if the object
 870                  *      being created is not a directory, then clear the
 871                  *      following flags: ACL_ENTRY_NO_PROPAGATE_INHERIT,
 872                  *      ACL_ENTRY_FILE_INHERIT, ACL_ENTRY_DIRECTORY_INHERIT,
 873                  *      ACL_ENTRY_INHERIT_ONLY.
 874                  */
 875                 if (entry->ae_flags & ACL_ENTRY_NO_PROPAGATE_INHERIT ||
 876                     !is_directory) {
 877                         entry->ae_flags &= ~(ACL_ENTRY_NO_PROPAGATE_INHERIT |
 878                         ACL_ENTRY_FILE_INHERIT | ACL_ENTRY_DIRECTORY_INHERIT |
 879                         ACL_ENTRY_INHERIT_ONLY);
 880
 881                         /*
 882                          * Continue on to the next ACE.
 883                          */
 884                         continue;
 885                 }
 886
 887                 /*
 888                  * 2.B. If the object is a directory and ACL_ENTRY_FILE_INHERIT
 889                  *      is set, but ACL_ENTRY_NO_PROPAGATE_INHERIT is not set, ensure
 890                  *      that ACL_ENTRY_INHERIT_ONLY is set.  Continue to the
 891                  *      next ACE.  Otherwise...
 892                  */
 893                 /*
 894                  * XXX: Read it again and make sure what does the "otherwise"
 895                  *      apply to.
 896                  */
 897                 if (is_directory &&
 898                     (entry->ae_flags & ACL_ENTRY_FILE_INHERIT) &&
 899                     ((entry->ae_flags & ACL_ENTRY_DIRECTORY_INHERIT) == 0)) {
 900                         entry->ae_flags |= ACL_ENTRY_INHERIT_ONLY;
 901                         continue;
 902                 }
 903
 904                 /*
 905                  * 2.C. If the type of the ACE is neither ALLOW nor deny,
 906                  *      then continue.
 907                  */
 908                 if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
 909                     entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
 910                         continue;
 911
 912                 /*
 913                  * 2.D. Copy the original ACE into a second, adjacent ACE.
 914                  */
 915                 copy = _acl_duplicate_entry(child_aclp, i);
 916
 917                 /*
 918                  * 2.E. On the first ACE, ensure that ACL_ENTRY_INHERIT_ONLY
 919                  *      is set.
 920                  */
 921                 entry->ae_flags |= ACL_ENTRY_INHERIT_ONLY;
 922
 923                 /*
 924                  * 2.F. On the second ACE, clear the following flags:
 925                  *      ACL_ENTRY_NO_PROPAGATE_INHERIT, ACL_ENTRY_FILE_INHERIT,
 926                  *      ACL_ENTRY_DIRECTORY_INHERIT, ACL_ENTRY_INHERIT_ONLY.
 927                  */
 928                 copy->ae_flags &= ~(ACL_ENTRY_NO_PROPAGATE_INHERIT |
 929                     ACL_ENTRY_FILE_INHERIT | ACL_ENTRY_DIRECTORY_INHERIT |
 930                     ACL_ENTRY_INHERIT_ONLY);
 931
 932                 /*
 933                  * 2.G. On the second ACE, if the type is ALLOW,
 934                  *      an implementation MAY clear the following
 935                  *      mask bits: ACL_WRITE_ACL, ACL_WRITE_OWNER.
 936                  */
 937                 if (copy->ae_entry_type == ACL_ENTRY_TYPE_ALLOW)
 938                         copy->ae_perm &= ~(ACL_WRITE_ACL | ACL_WRITE_OWNER);
 939
 940                 /*
 941                  * Increment the counter to skip the copied entry.
 942                  */
 943                 i++;
 944         }
 945
 946         /*
 947          * 3. To ensure that the mode is honored, apply the algorithm describe
 948          *    in Section 2.16.6.3, using the mode that is to be used for file
 949          *    creation.
 950          */
 951         acl_nfs4_sync_acl_from_mode(child_aclp, mode, file_owner_id);
 952 }
 953
 954 #ifdef _KERNEL
 955 static int
 956 _acls_are_equal(const struct acl *a, const struct acl *b)
 957 {
 958         int i;
 959         const struct acl_entry *entrya, *entryb;
 960
 961         if (a->acl_cnt != b->acl_cnt)
 962                 return (0);
 963
 964         for (i = 0; i < b->acl_cnt; i++) {
 965                 entrya = &(a->acl_entry[i]);
 966                 entryb = &(b->acl_entry[i]);
 967
 968                 if (entrya->ae_tag != entryb->ae_tag ||
 969                     entrya->ae_id != entryb->ae_id ||
 970                     entrya->ae_perm != entryb->ae_perm ||
 971                     entrya->ae_entry_type != entryb->ae_entry_type ||
 972                     entrya->ae_flags != entryb->ae_flags)
 973                         return (0);
 974         }
 975
 976         return (1);
 977 }
 978
 979 /*
 980  * This routine is used to determine whether to remove entry_type attribute
 981  * that stores ACL contents.
 982  */
 983 int
 984 acl_nfs4_is_trivial(const struct acl *aclp, int file_owner_id)
 985 {
 986         int trivial;
 987         mode_t tmpmode = 0;
 988         struct acl *tmpaclp;
 989
 990         if (aclp->acl_cnt != 6)
 991                 return (0);
 992
 993         /*
 994          * Compute the mode from the ACL, then compute new ACL from that mode.
 995          * If the ACLs are identical, then the ACL is trivial.
 996          *
 997          * XXX: I guess there is a faster way to do this.  However, even
 998          *      this slow implementation significantly speeds things up
 999          *      for files that don't have any entry_type ACL entries - it's
1000          *      critical for performance to not use EA when they are not
1001          *      needed.
1002          */
1003         tmpaclp = acl_alloc(M_WAITOK | M_ZERO);
1004         acl_nfs4_sync_mode_from_acl(&tmpmode, aclp);
1005         acl_nfs4_sync_acl_from_mode(tmpaclp, tmpmode, file_owner_id);
1006         trivial = _acls_are_equal(aclp, tmpaclp);
1007         acl_free(tmpaclp);
1008
1009         return (trivial);
1010 }
1011 #endif /* _KERNEL */
1012
1013 int
1014 acl_nfs4_check(const struct acl *aclp, int is_directory)
1015 {
1016         int i;
1017         const struct acl_entry *entry;
1018
1019         /*
1020          * The spec doesn't seem to say anything about ACL validity.
1021          * It seems there is not much to do here.  There is even no need
1022          * to count "owner@" or "everyone@" (ACL_USER_OBJ and ACL_EVERYONE)
1023          * entries, as there can be several of them and that's perfectly
1024          * valid.  There can be none of them too.  Really.
1025          */
1026
1027         if (aclp->acl_cnt > ACL_MAX_ENTRIES || aclp->acl_cnt <= 0)
1028                 return (EINVAL);
1029
1030         for (i = 0; i < aclp->acl_cnt; i++) {
1031                 entry = &(aclp->acl_entry[i]);
1032
1033                 switch (entry->ae_tag) {
1034                 case ACL_USER_OBJ:
1035                 case ACL_GROUP_OBJ:
1036                 case ACL_EVERYONE:
1037                         if (entry->ae_id != ACL_UNDEFINED_ID)
1038                                 return (EINVAL);
1039                         break;
1040
1041                 case ACL_USER:
1042                 case ACL_GROUP:
1043                         if (entry->ae_id == ACL_UNDEFINED_ID)
1044                                 return (EINVAL);
1045                         break;
1046
1047                 default:
1048                         return (EINVAL);
1049                 }
1050
1051                 if ((entry->ae_perm | ACL_NFS4_PERM_BITS) != ACL_NFS4_PERM_BITS)
1052                         return (EINVAL);
1053
1054                 /*
1055                  * Disallow ACL_ENTRY_TYPE_AUDIT and ACL_ENTRY_TYPE_ALARM for now.
1056                  */
1057                 if (entry->ae_entry_type != ACL_ENTRY_TYPE_ALLOW &&
1058                     entry->ae_entry_type != ACL_ENTRY_TYPE_DENY)
1059                         return (EINVAL);
1060
1061                 if ((entry->ae_flags | ACL_FLAGS_BITS) != ACL_FLAGS_BITS)
1062                         return (EINVAL);
1063
1064                 /* Disallow unimplemented flags. */
1065                 if (entry->ae_flags & (ACL_ENTRY_SUCCESSFUL_ACCESS |
1066                     ACL_ENTRY_FAILED_ACCESS))
1067                         return (EINVAL);
1068
1069                 /* Disallow flags not allowed for ordinary files. */
1070                 if (!is_directory) {
1071                         if (entry->ae_flags & (ACL_ENTRY_FILE_INHERIT |
1072                             ACL_ENTRY_DIRECTORY_INHERIT |
1073                             ACL_ENTRY_NO_PROPAGATE_INHERIT | ACL_ENTRY_INHERIT_ONLY))
1074                                 return (EINVAL);
1075                 }
1076         }
1077
1078         return (0);
1079 }