fs/xfs/xfs_acl.c

   1 /*
   2  * Copyright (c) 2001-2002,2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #include "xfs.h"
  19 #include "xfs_fs.h"
  20 #include "xfs_types.h"
  21 #include "xfs_bit.h"
  22 #include "xfs_inum.h"
  23 #include "xfs_ag.h"
  24 #include "xfs_dir.h"
  25 #include "xfs_dir2.h"
  26 #include "xfs_bmap_btree.h"
  27 #include "xfs_alloc_btree.h"
  28 #include "xfs_ialloc_btree.h"
  29 #include "xfs_dir_sf.h"
  30 #include "xfs_dir2_sf.h"
  31 #include "xfs_attr_sf.h"
  32 #include "xfs_dinode.h"
  33 #include "xfs_inode.h"
  34 #include "xfs_btree.h"
  35 #include "xfs_acl.h"
  36 #include "xfs_mac.h"
  37 #include "xfs_attr.h"
  38
  39 #include <linux/posix_acl_xattr.h>
  40
  41 STATIC int      xfs_acl_setmode(vnode_t *, xfs_acl_t *, int *);
  42 STATIC void     xfs_acl_filter_mode(mode_t, xfs_acl_t *);
  43 STATIC void     xfs_acl_get_endian(xfs_acl_t *);
  44 STATIC int      xfs_acl_access(uid_t, gid_t, xfs_acl_t *, mode_t, cred_t *);
  45 STATIC int      xfs_acl_invalid(xfs_acl_t *);
  46 STATIC void     xfs_acl_sync_mode(mode_t, xfs_acl_t *);
  47 STATIC void     xfs_acl_get_attr(vnode_t *, xfs_acl_t *, int, int, int *);
  48 STATIC void     xfs_acl_set_attr(vnode_t *, xfs_acl_t *, int, int *);
  49 STATIC int      xfs_acl_allow_set(vnode_t *, int);
  50
  51 kmem_zone_t *xfs_acl_zone;
  52
  53
  54 /*
  55  * Test for existence of access ACL attribute as efficiently as possible.
  56  */
  57 int
  58 xfs_acl_vhasacl_access(
  59         vnode_t         *vp)
  60 {
  61         int             error;
  62
  63         xfs_acl_get_attr(vp, NULL, _ACL_TYPE_ACCESS, ATTR_KERNOVAL, &error);
  64         return (error == 0);
  65 }
  66
  67 /*
  68  * Test for existence of default ACL attribute as efficiently as possible.
  69  */
  70 int
  71 xfs_acl_vhasacl_default(
  72         vnode_t         *vp)
  73 {
  74         int             error;
  75
  76         if (!VN_ISDIR(vp))
  77                 return 0;
  78         xfs_acl_get_attr(vp, NULL, _ACL_TYPE_DEFAULT, ATTR_KERNOVAL, &error);
  79         return (error == 0);
  80 }
  81
  82 /*
  83  * Convert from extended attribute representation to in-memory for XFS.
  84  */
  85 STATIC int
  86 posix_acl_xattr_to_xfs(
  87         posix_acl_xattr_header  *src,
  88         size_t                  size,
  89         xfs_acl_t               *dest)
  90 {
  91         posix_acl_xattr_entry   *src_entry;
  92         xfs_acl_entry_t         *dest_entry;
  93         int                     n;
  94
  95         if (!src || !dest)
  96                 return EINVAL;
  97
  98         if (size < sizeof(posix_acl_xattr_header))
  99                 return EINVAL;
 100
 101         if (src->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
 102                 return EOPNOTSUPP;
 103
 104         memset(dest, 0, sizeof(xfs_acl_t));
 105         dest->acl_cnt = posix_acl_xattr_count(size);
 106         if (dest->acl_cnt < 0 || dest->acl_cnt > XFS_ACL_MAX_ENTRIES)
 107                 return EINVAL;
 108
 109         /*
 110          * acl_set_file(3) may request that we set default ACLs with
 111          * zero length -- defend (gracefully) against that here.
 112          */
 113         if (!dest->acl_cnt)
 114                 return 0;
 115
 116         src_entry = (posix_acl_xattr_entry *)((char *)src + sizeof(*src));
 117         dest_entry = &dest->acl_entry[0];
 118
 119         for (n = 0; n < dest->acl_cnt; n++, src_entry++, dest_entry++) {
 120                 dest_entry->ae_perm = le16_to_cpu(src_entry->e_perm);
 121                 if (_ACL_PERM_INVALID(dest_entry->ae_perm))
 122                         return EINVAL;
 123                 dest_entry->ae_tag  = le16_to_cpu(src_entry->e_tag);
 124                 switch(dest_entry->ae_tag) {
 125                 case ACL_USER:
 126                 case ACL_GROUP:
 127                         dest_entry->ae_id = le32_to_cpu(src_entry->e_id);
 128                         break;
 129                 case ACL_USER_OBJ:
 130                 case ACL_GROUP_OBJ:
 131                 case ACL_MASK:
 132                 case ACL_OTHER:
 133                         dest_entry->ae_id = ACL_UNDEFINED_ID;
 134                         break;
 135                 default:
 136                         return EINVAL;
 137                 }
 138         }
 139         if (xfs_acl_invalid(dest))
 140                 return EINVAL;
 141
 142         return 0;
 143 }
 144
 145 /*
 146  * Comparison function called from xfs_sort().
 147  * Primary key is ae_tag, secondary key is ae_id.
 148  */
 149 STATIC int
 150 xfs_acl_entry_compare(
 151         const void      *va,
 152         const void      *vb)
 153 {
 154         xfs_acl_entry_t *a = (xfs_acl_entry_t *)va,
 155                         *b = (xfs_acl_entry_t *)vb;
 156
 157         if (a->ae_tag == b->ae_tag)
 158                 return (a->ae_id - b->ae_id);
 159         return (a->ae_tag - b->ae_tag);
 160 }
 161
 162 /*
 163  * Convert from in-memory XFS to extended attribute representation.
 164  */
 165 STATIC int
 166 posix_acl_xfs_to_xattr(
 167         xfs_acl_t               *src,
 168         posix_acl_xattr_header  *dest,
 169         size_t                  size)
 170 {
 171         int                     n;
 172         size_t                  new_size = posix_acl_xattr_size(src->acl_cnt);
 173         posix_acl_xattr_entry   *dest_entry;
 174         xfs_acl_entry_t         *src_entry;
 175
 176         if (size < new_size)
 177                 return -ERANGE;
 178
 179         /* Need to sort src XFS ACL by <ae_tag,ae_id> */
 180         xfs_sort(src->acl_entry, src->acl_cnt, sizeof(src->acl_entry[0]),
 181                  xfs_acl_entry_compare);
 182
 183         dest->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
 184         dest_entry = &dest->a_entries[0];
 185         src_entry = &src->acl_entry[0];
 186         for (n = 0; n < src->acl_cnt; n++, dest_entry++, src_entry++) {
 187                 dest_entry->e_perm = cpu_to_le16(src_entry->ae_perm);
 188                 if (_ACL_PERM_INVALID(src_entry->ae_perm))
 189                         return -EINVAL;
 190                 dest_entry->e_tag  = cpu_to_le16(src_entry->ae_tag);
 191                 switch (src_entry->ae_tag) {
 192                 case ACL_USER:
 193                 case ACL_GROUP:
 194                         dest_entry->e_id = cpu_to_le32(src_entry->ae_id);
 195                                 break;
 196                 case ACL_USER_OBJ:
 197                 case ACL_GROUP_OBJ:
 198                 case ACL_MASK:
 199                 case ACL_OTHER:
 200                         dest_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
 201                         break;
 202                 default:
 203                         return -EINVAL;
 204                 }
 205         }
 206         return new_size;
 207 }
 208
 209 int
 210 xfs_acl_vget(
 211         vnode_t         *vp,
 212         void            *acl,
 213         size_t          size,
 214         int             kind)
 215 {
 216         int                     error;
 217         xfs_acl_t               *xfs_acl = NULL;
 218         posix_acl_xattr_header  *ext_acl = acl;
 219         int                     flags = 0;
 220
 221         VN_HOLD(vp);
 222         if(size) {
 223                 if (!(_ACL_ALLOC(xfs_acl))) {
 224                         error = ENOMEM;
 225                         goto out;
 226                 }
 227                 memset(xfs_acl, 0, sizeof(xfs_acl_t));
 228         } else
 229                 flags = ATTR_KERNOVAL;
 230
 231         xfs_acl_get_attr(vp, xfs_acl, kind, flags, &error);
 232         if (error)
 233                 goto out;
 234
 235         if (!size) {
 236                 error = -posix_acl_xattr_size(XFS_ACL_MAX_ENTRIES);
 237         } else {
 238                 if (xfs_acl_invalid(xfs_acl)) {
 239                         error = EINVAL;
 240                         goto out;
 241                 }
 242                 if (kind == _ACL_TYPE_ACCESS) {
 243                         vattr_t va;
 244
 245                         va.va_mask = XFS_AT_MODE;
 246                         VOP_GETATTR(vp, &va, 0, sys_cred, error);
 247                         if (error)
 248                                 goto out;
 249                         xfs_acl_sync_mode(va.va_mode, xfs_acl);
 250                 }
 251                 error = -posix_acl_xfs_to_xattr(xfs_acl, ext_acl, size);
 252         }
 253 out:
 254         VN_RELE(vp);
 255         if(xfs_acl)
 256                 _ACL_FREE(xfs_acl);
 257         return -error;
 258 }
 259
 260 int
 261 xfs_acl_vremove(
 262         vnode_t         *vp,
 263         int             kind)
 264 {
 265         int             error;
 266
 267         VN_HOLD(vp);
 268         error = xfs_acl_allow_set(vp, kind);
 269         if (!error) {
 270                 VOP_ATTR_REMOVE(vp, kind == _ACL_TYPE_DEFAULT?
 271                                 SGI_ACL_DEFAULT: SGI_ACL_FILE,
 272                                 ATTR_ROOT, sys_cred, error);
 273                 if (error == ENOATTR)
 274                         error = 0;      /* 'scool */
 275         }
 276         VN_RELE(vp);
 277         return -error;
 278 }
 279
 280 int
 281 xfs_acl_vset(
 282         vnode_t                 *vp,
 283         void                    *acl,
 284         size_t                  size,
 285         int                     kind)
 286 {
 287         posix_acl_xattr_header  *ext_acl = acl;
 288         xfs_acl_t               *xfs_acl;
 289         int                     error;
 290         int                     basicperms = 0; /* more than std unix perms? */
 291
 292         if (!acl)
 293                 return -EINVAL;
 294
 295         if (!(_ACL_ALLOC(xfs_acl)))
 296                 return -ENOMEM;
 297
 298         error = posix_acl_xattr_to_xfs(ext_acl, size, xfs_acl);
 299         if (error) {
 300                 _ACL_FREE(xfs_acl);
 301                 return -error;
 302         }
 303         if (!xfs_acl->acl_cnt) {
 304                 _ACL_FREE(xfs_acl);
 305                 return 0;
 306         }
 307
 308         VN_HOLD(vp);
 309         error = xfs_acl_allow_set(vp, kind);
 310         if (error)
 311                 goto out;
 312
 313         /* Incoming ACL exists, set file mode based on its value */
 314         if (kind == _ACL_TYPE_ACCESS)
 315                 xfs_acl_setmode(vp, xfs_acl, &basicperms);
 316
 317         /*
 318          * If we have more than std unix permissions, set up the actual attr.
 319          * Otherwise, delete any existing attr.  This prevents us from
 320          * having actual attrs for permissions that can be stored in the
 321          * standard permission bits.
 322          */
 323         if (!basicperms) {
 324                 xfs_acl_set_attr(vp, xfs_acl, kind, &error);
 325         } else {
 326                 xfs_acl_vremove(vp, _ACL_TYPE_ACCESS);
 327         }
 328
 329 out:
 330         VN_RELE(vp);
 331         _ACL_FREE(xfs_acl);
 332         return -error;
 333 }
 334
 335 int
 336 xfs_acl_iaccess(
 337         xfs_inode_t     *ip,
 338         mode_t          mode,
 339         cred_t          *cr)
 340 {
 341         xfs_acl_t       *acl;
 342         int             rval;
 343
 344         if (!(_ACL_ALLOC(acl)))
 345                 return -1;
 346
 347         /* If the file has no ACL return -1. */
 348         rval = sizeof(xfs_acl_t);
 349         if (xfs_attr_fetch(ip, SGI_ACL_FILE, SGI_ACL_FILE_SIZE,
 350                         (char *)acl, &rval, ATTR_ROOT | ATTR_KERNACCESS, cr)) {
 351                 _ACL_FREE(acl);
 352                 return -1;
 353         }
 354         xfs_acl_get_endian(acl);
 355
 356         /* If the file has an empty ACL return -1. */
 357         if (acl->acl_cnt == XFS_ACL_NOT_PRESENT) {
 358                 _ACL_FREE(acl);
 359                 return -1;
 360         }
 361
 362         /* Synchronize ACL with mode bits */
 363         xfs_acl_sync_mode(ip->i_d.di_mode, acl);
 364
 365         rval = xfs_acl_access(ip->i_d.di_uid, ip->i_d.di_gid, acl, mode, cr);
 366         _ACL_FREE(acl);
 367         return rval;
 368 }
 369
 370 STATIC int
 371 xfs_acl_allow_set(
 372         vnode_t         *vp,
 373         int             kind)
 374 {
 375         vattr_t         va;
 376         int             error;
 377
 378         if (vp->v_inode.i_flags & (S_IMMUTABLE|S_APPEND))
 379                 return EPERM;
 380         if (kind == _ACL_TYPE_DEFAULT && !VN_ISDIR(vp))
 381                 return ENOTDIR;
 382         if (vp->v_vfsp->vfs_flag & VFS_RDONLY)
 383                 return EROFS;
 384         va.va_mask = XFS_AT_UID;
 385         VOP_GETATTR(vp, &va, 0, NULL, error);
 386         if (error)
 387                 return error;
 388         if (va.va_uid != current->fsuid && !capable(CAP_FOWNER))
 389                 return EPERM;
 390         return error;
 391 }
 392
 393 /*
 394  * The access control process to determine the access permission:
 395  *      if uid == file owner id, use the file owner bits.
 396  *      if gid == file owner group id, use the file group bits.
 397  *      scan ACL for a maching user or group, and use matched entry
 398  *      permission. Use total permissions of all matching group entries,
 399  *      until all acl entries are exhausted. The final permission produced
 400  *      by matching acl entry or entries needs to be & with group permission.
 401  *      if not owner, owning group, or matching entry in ACL, use file
 402  *      other bits.
 403  */
 404 STATIC int
 405 xfs_acl_capability_check(
 406         mode_t          mode,
 407         cred_t          *cr)
 408 {
 409         if ((mode & ACL_READ) && !capable_cred(cr, CAP_DAC_READ_SEARCH))
 410                 return EACCES;
 411         if ((mode & ACL_WRITE) && !capable_cred(cr, CAP_DAC_OVERRIDE))
 412                 return EACCES;
 413         if ((mode & ACL_EXECUTE) && !capable_cred(cr, CAP_DAC_OVERRIDE))
 414                 return EACCES;
 415
 416         return 0;
 417 }
 418
 419 /*
 420  * Note: cr is only used here for the capability check if the ACL test fails.
 421  *       It is not used to find out the credentials uid or groups etc, as was
 422  *       done in IRIX. It is assumed that the uid and groups for the current
 423  *       thread are taken from "current" instead of the cr parameter.
 424  */
 425 STATIC int
 426 xfs_acl_access(
 427         uid_t           fuid,
 428         gid_t           fgid,
 429         xfs_acl_t       *fap,
 430         mode_t          md,
 431         cred_t          *cr)
 432 {
 433         xfs_acl_entry_t matched;
 434         int             i, allows;
 435         int             maskallows = -1;        /* true, but not 1, either */
 436         int             seen_userobj = 0;
 437
 438         matched.ae_tag = 0;     /* Invalid type */
 439         matched.ae_perm = 0;
 440         md >>= 6;       /* Normalize the bits for comparison */
 441
 442         for (i = 0; i < fap->acl_cnt; i++) {
 443                 /*
 444                  * Break out if we've got a user_obj entry or
 445                  * a user entry and the mask (and have processed USER_OBJ)
 446                  */
 447                 if (matched.ae_tag == ACL_USER_OBJ)
 448                         break;
 449                 if (matched.ae_tag == ACL_USER) {
 450                         if (maskallows != -1 && seen_userobj)
 451                                 break;
 452                         if (fap->acl_entry[i].ae_tag != ACL_MASK &&
 453                             fap->acl_entry[i].ae_tag != ACL_USER_OBJ)
 454                                 continue;
 455                 }
 456                 /* True if this entry allows the requested access */
 457                 allows = ((fap->acl_entry[i].ae_perm & md) == md);
 458
 459                 switch (fap->acl_entry[i].ae_tag) {
 460                 case ACL_USER_OBJ:
 461                         seen_userobj = 1;
 462                         if (fuid != current->fsuid)
 463                                 continue;
 464                         matched.ae_tag = ACL_USER_OBJ;
 465                         matched.ae_perm = allows;
 466                         break;
 467                 case ACL_USER:
 468                         if (fap->acl_entry[i].ae_id != current->fsuid)
 469                                 continue;
 470                         matched.ae_tag = ACL_USER;
 471                         matched.ae_perm = allows;
 472                         break;
 473                 case ACL_GROUP_OBJ:
 474                         if ((matched.ae_tag == ACL_GROUP_OBJ ||
 475                             matched.ae_tag == ACL_GROUP) && !allows)
 476                                 continue;
 477                         if (!in_group_p(fgid))
 478                                 continue;
 479                         matched.ae_tag = ACL_GROUP_OBJ;
 480                         matched.ae_perm = allows;
 481                         break;
 482                 case ACL_GROUP:
 483                         if ((matched.ae_tag == ACL_GROUP_OBJ ||
 484                             matched.ae_tag == ACL_GROUP) && !allows)
 485                                 continue;
 486                         if (!in_group_p(fap->acl_entry[i].ae_id))
 487                                 continue;
 488                         matched.ae_tag = ACL_GROUP;
 489                         matched.ae_perm = allows;
 490                         break;
 491                 case ACL_MASK:
 492                         maskallows = allows;
 493                         break;
 494                 case ACL_OTHER:
 495                         if (matched.ae_tag != 0)
 496                                 continue;
 497                         matched.ae_tag = ACL_OTHER;
 498                         matched.ae_perm = allows;
 499                         break;
 500                 }
 501         }
 502         /*
 503          * First possibility is that no matched entry allows access.
 504          * The capability to override DAC may exist, so check for it.
 505          */
 506         switch (matched.ae_tag) {
 507         case ACL_OTHER:
 508         case ACL_USER_OBJ:
 509                 if (matched.ae_perm)
 510                         return 0;
 511                 break;
 512         case ACL_USER:
 513         case ACL_GROUP_OBJ:
 514         case ACL_GROUP:
 515                 if (maskallows && matched.ae_perm)
 516                         return 0;
 517                 break;
 518         case 0:
 519                 break;
 520         }
 521
 522         return xfs_acl_capability_check(md, cr);
 523 }
 524
 525 /*
 526  * ACL validity checker.
 527  *   This acl validation routine checks each ACL entry read in makes sense.
 528  */
 529 STATIC int
 530 xfs_acl_invalid(
 531         xfs_acl_t       *aclp)
 532 {
 533         xfs_acl_entry_t *entry, *e;
 534         int             user = 0, group = 0, other = 0, mask = 0;
 535         int             mask_required = 0;
 536         int             i, j;
 537
 538         if (!aclp)
 539                 goto acl_invalid;
 540
 541         if (aclp->acl_cnt > XFS_ACL_MAX_ENTRIES)
 542                 goto acl_invalid;
 543
 544         for (i = 0; i < aclp->acl_cnt; i++) {
 545                 entry = &aclp->acl_entry[i];
 546                 switch (entry->ae_tag) {
 547                 case ACL_USER_OBJ:
 548                         if (user++)
 549                                 goto acl_invalid;
 550                         break;
 551                 case ACL_GROUP_OBJ:
 552                         if (group++)
 553                                 goto acl_invalid;
 554                         break;
 555                 case ACL_OTHER:
 556                         if (other++)
 557                                 goto acl_invalid;
 558                         break;
 559                 case ACL_USER:
 560                 case ACL_GROUP:
 561                         for (j = i + 1; j < aclp->acl_cnt; j++) {
 562                                 e = &aclp->acl_entry[j];
 563                                 if (e->ae_id == entry->ae_id &&
 564                                     e->ae_tag == entry->ae_tag)
 565                                         goto acl_invalid;
 566                         }
 567                         mask_required++;
 568                         break;
 569                 case ACL_MASK:
 570                         if (mask++)
 571                                 goto acl_invalid;
 572                         break;
 573                 default:
 574                         goto acl_invalid;
 575                 }
 576         }
 577         if (!user || !group || !other || (mask_required && !mask))
 578                 goto acl_invalid;
 579         else
 580                 return 0;
 581 acl_invalid:
 582         return EINVAL;
 583 }
 584
 585 /*
 586  * Do ACL endian conversion.
 587  */
 588 STATIC void
 589 xfs_acl_get_endian(
 590         xfs_acl_t       *aclp)
 591 {
 592         xfs_acl_entry_t *ace, *end;
 593
 594         INT_SET(aclp->acl_cnt, ARCH_CONVERT, aclp->acl_cnt);
 595         end = &aclp->acl_entry[0]+aclp->acl_cnt;
 596         for (ace = &aclp->acl_entry[0]; ace < end; ace++) {
 597                 INT_SET(ace->ae_tag, ARCH_CONVERT, ace->ae_tag);
 598                 INT_SET(ace->ae_id, ARCH_CONVERT, ace->ae_id);
 599                 INT_SET(ace->ae_perm, ARCH_CONVERT, ace->ae_perm);
 600         }
 601 }
 602
 603 /*
 604  * Get the ACL from the EA and do endian conversion.
 605  */
 606 STATIC void
 607 xfs_acl_get_attr(
 608         vnode_t         *vp,
 609         xfs_acl_t       *aclp,
 610         int             kind,
 611         int             flags,
 612         int             *error)
 613 {
 614         int             len = sizeof(xfs_acl_t);
 615
 616         ASSERT((flags & ATTR_KERNOVAL) ? (aclp == NULL) : 1);
 617         flags |= ATTR_ROOT;
 618         VOP_ATTR_GET(vp,
 619                 kind == _ACL_TYPE_ACCESS ? SGI_ACL_FILE : SGI_ACL_DEFAULT,
 620                 (char *)aclp, &len, flags, sys_cred, *error);
 621         if (*error || (flags & ATTR_KERNOVAL))
 622                 return;
 623         xfs_acl_get_endian(aclp);
 624 }
 625
 626 /*
 627  * Set the EA with the ACL and do endian conversion.
 628  */
 629 STATIC void
 630 xfs_acl_set_attr(
 631         vnode_t         *vp,
 632         xfs_acl_t       *aclp,
 633         int             kind,
 634         int             *error)
 635 {
 636         xfs_acl_entry_t *ace, *newace, *end;
 637         xfs_acl_t       *newacl;
 638         int             len;
 639
 640         if (!(_ACL_ALLOC(newacl))) {
 641                 *error = ENOMEM;
 642                 return;
 643         }
 644
 645         len = sizeof(xfs_acl_t) -
 646               (sizeof(xfs_acl_entry_t) * (XFS_ACL_MAX_ENTRIES - aclp->acl_cnt));
 647         end = &aclp->acl_entry[0]+aclp->acl_cnt;
 648         for (ace = &aclp->acl_entry[0], newace = &newacl->acl_entry[0];
 649              ace < end;
 650              ace++, newace++) {
 651                 INT_SET(newace->ae_tag, ARCH_CONVERT, ace->ae_tag);
 652                 INT_SET(newace->ae_id, ARCH_CONVERT, ace->ae_id);
 653                 INT_SET(newace->ae_perm, ARCH_CONVERT, ace->ae_perm);
 654         }
 655         INT_SET(newacl->acl_cnt, ARCH_CONVERT, aclp->acl_cnt);
 656         VOP_ATTR_SET(vp,
 657                 kind == _ACL_TYPE_ACCESS ? SGI_ACL_FILE: SGI_ACL_DEFAULT,
 658                 (char *)newacl, len, ATTR_ROOT, sys_cred, *error);
 659         _ACL_FREE(newacl);
 660 }
 661
 662 int
 663 xfs_acl_vtoacl(
 664         vnode_t         *vp,
 665         xfs_acl_t       *access_acl,
 666         xfs_acl_t       *default_acl)
 667 {
 668         vattr_t         va;
 669         int             error = 0;
 670
 671         if (access_acl) {
 672                 /*
 673                  * Get the Access ACL and the mode.  If either cannot
 674                  * be obtained for some reason, invalidate the access ACL.
 675                  */
 676                 xfs_acl_get_attr(vp, access_acl, _ACL_TYPE_ACCESS, 0, &error);
 677                 if (!error) {
 678                         /* Got the ACL, need the mode... */
 679                         va.va_mask = XFS_AT_MODE;
 680                         VOP_GETATTR(vp, &va, 0, sys_cred, error);
 681                 }
 682
 683                 if (error)
 684                         access_acl->acl_cnt = XFS_ACL_NOT_PRESENT;
 685                 else /* We have a good ACL and the file mode, synchronize. */
 686                         xfs_acl_sync_mode(va.va_mode, access_acl);
 687         }
 688
 689         if (default_acl) {
 690                 xfs_acl_get_attr(vp, default_acl, _ACL_TYPE_DEFAULT, 0, &error);
 691                 if (error)
 692                         default_acl->acl_cnt = XFS_ACL_NOT_PRESENT;
 693         }
 694         return error;
 695 }
 696
 697 /*
 698  * This function retrieves the parent directory's acl, processes it
 699  * and lets the child inherit the acl(s) that it should.
 700  */
 701 int
 702 xfs_acl_inherit(
 703         vnode_t         *vp,
 704         vattr_t         *vap,
 705         xfs_acl_t       *pdaclp)
 706 {
 707         xfs_acl_t       *cacl;
 708         int             error = 0;
 709         int             basicperms = 0;
 710
 711         /*
 712          * If the parent does not have a default ACL, or it's an
 713          * invalid ACL, we're done.
 714          */
 715         if (!vp)
 716                 return 0;
 717         if (!pdaclp || xfs_acl_invalid(pdaclp))
 718                 return 0;
 719
 720         /*
 721          * Copy the default ACL of the containing directory to
 722          * the access ACL of the new file and use the mode that
 723          * was passed in to set up the correct initial values for
 724          * the u::,g::[m::], and o:: entries.  This is what makes
 725          * umask() "work" with ACL's.
 726          */
 727
 728         if (!(_ACL_ALLOC(cacl)))
 729                 return ENOMEM;
 730
 731         memcpy(cacl, pdaclp, sizeof(xfs_acl_t));
 732         xfs_acl_filter_mode(vap->va_mode, cacl);
 733         xfs_acl_setmode(vp, cacl, &basicperms);
 734
 735         /*
 736          * Set the Default and Access ACL on the file.  The mode is already
 737          * set on the file, so we don't need to worry about that.
 738          *
 739          * If the new file is a directory, its default ACL is a copy of
 740          * the containing directory's default ACL.
 741          */
 742         if (VN_ISDIR(vp))
 743                 xfs_acl_set_attr(vp, pdaclp, _ACL_TYPE_DEFAULT, &error);
 744         if (!error && !basicperms)
 745                 xfs_acl_set_attr(vp, cacl, _ACL_TYPE_ACCESS, &error);
 746         _ACL_FREE(cacl);
 747         return error;
 748 }
 749
 750 /*
 751  * Set up the correct mode on the file based on the supplied ACL.  This
 752  * makes sure that the mode on the file reflects the state of the
 753  * u::,g::[m::], and o:: entries in the ACL.  Since the mode is where
 754  * the ACL is going to get the permissions for these entries, we must
 755  * synchronize the mode whenever we set the ACL on a file.
 756  */
 757 STATIC int
 758 xfs_acl_setmode(
 759         vnode_t         *vp,
 760         xfs_acl_t       *acl,
 761         int             *basicperms)
 762 {
 763         vattr_t         va;
 764         xfs_acl_entry_t *ap;
 765         xfs_acl_entry_t *gap = NULL;
 766         int             i, error, nomask = 1;
 767
 768         *basicperms = 1;
 769
 770         if (acl->acl_cnt == XFS_ACL_NOT_PRESENT)
 771                 return 0;
 772
 773         /*
 774          * Copy the u::, g::, o::, and m:: bits from the ACL into the
 775          * mode.  The m:: bits take precedence over the g:: bits.
 776          */
 777         va.va_mask = XFS_AT_MODE;
 778         VOP_GETATTR(vp, &va, 0, sys_cred, error);
 779         if (error)
 780                 return error;
 781
 782         va.va_mask = XFS_AT_MODE;
 783         va.va_mode &= ~(S_IRWXU|S_IRWXG|S_IRWXO);
 784         ap = acl->acl_entry;
 785         for (i = 0; i < acl->acl_cnt; ++i) {
 786                 switch (ap->ae_tag) {
 787                 case ACL_USER_OBJ:
 788                         va.va_mode |= ap->ae_perm << 6;
 789                         break;
 790                 case ACL_GROUP_OBJ:
 791                         gap = ap;
 792                         break;
 793                 case ACL_MASK:  /* more than just standard modes */
 794                         nomask = 0;
 795                         va.va_mode |= ap->ae_perm << 3;
 796                         *basicperms = 0;
 797                         break;
 798                 case ACL_OTHER:
 799                         va.va_mode |= ap->ae_perm;
 800                         break;
 801                 default:        /* more than just standard modes */
 802                         *basicperms = 0;
 803                         break;
 804                 }
 805                 ap++;
 806         }
 807
 808         /* Set the group bits from ACL_GROUP_OBJ if there's no ACL_MASK */
 809         if (gap && nomask)
 810                 va.va_mode |= gap->ae_perm << 3;
 811
 812         VOP_SETATTR(vp, &va, 0, sys_cred, error);
 813         return error;
 814 }
 815
 816 /*
 817  * The permissions for the special ACL entries (u::, g::[m::], o::) are
 818  * actually stored in the file mode (if there is both a group and a mask,
 819  * the group is stored in the ACL entry and the mask is stored on the file).
 820  * This allows the mode to remain automatically in sync with the ACL without
 821  * the need for a call-back to the ACL system at every point where the mode
 822  * could change.  This function takes the permissions from the specified mode
 823  * and places it in the supplied ACL.
 824  *
 825  * This implementation draws its validity from the fact that, when the ACL
 826  * was assigned, the mode was copied from the ACL.
 827  * If the mode did not change, therefore, the mode remains exactly what was
 828  * taken from the special ACL entries at assignment.
 829  * If a subsequent chmod() was done, the POSIX spec says that the change in
 830  * mode must cause an update to the ACL seen at user level and used for
 831  * access checks.  Before and after a mode change, therefore, the file mode
 832  * most accurately reflects what the special ACL entries should permit/deny.
 833  *
 834  * CAVEAT: If someone sets the SGI_ACL_FILE attribute directly,
 835  *         the existing mode bits will override whatever is in the
 836  *         ACL. Similarly, if there is a pre-existing ACL that was
 837  *         never in sync with its mode (owing to a bug in 6.5 and
 838  *         before), it will now magically (or mystically) be
 839  *         synchronized.  This could cause slight astonishment, but
 840  *         it is better than inconsistent permissions.
 841  *
 842  * The supplied ACL is a template that may contain any combination
 843  * of special entries.  These are treated as place holders when we fill
 844  * out the ACL.  This routine does not add or remove special entries, it
 845  * simply unites each special entry with its associated set of permissions.
 846  */
 847 STATIC void
 848 xfs_acl_sync_mode(
 849         mode_t          mode,
 850         xfs_acl_t       *acl)
 851 {
 852         int             i, nomask = 1;
 853         xfs_acl_entry_t *ap;
 854         xfs_acl_entry_t *gap = NULL;
 855
 856         /*
 857          * Set ACL entries. POSIX1003.1eD16 requires that the MASK
 858          * be set instead of the GROUP entry, if there is a MASK.
 859          */
 860         for (ap = acl->acl_entry, i = 0; i < acl->acl_cnt; ap++, i++) {
 861                 switch (ap->ae_tag) {
 862                 case ACL_USER_OBJ:
 863                         ap->ae_perm = (mode >> 6) & 0x7;
 864                         break;
 865                 case ACL_GROUP_OBJ:
 866                         gap = ap;
 867                         break;
 868                 case ACL_MASK:
 869                         nomask = 0;
 870                         ap->ae_perm = (mode >> 3) & 0x7;
 871                         break;
 872                 case ACL_OTHER:
 873                         ap->ae_perm = mode & 0x7;
 874                         break;
 875                 default:
 876                         break;
 877                 }
 878         }
 879         /* Set the ACL_GROUP_OBJ if there's no ACL_MASK */
 880         if (gap && nomask)
 881                 gap->ae_perm = (mode >> 3) & 0x7;
 882 }
 883
 884 /*
 885  * When inheriting an Access ACL from a directory Default ACL,
 886  * the ACL bits are set to the intersection of the ACL default
 887  * permission bits and the file permission bits in mode. If there
 888  * are no permission bits on the file then we must not give them
 889  * the ACL. This is what what makes umask() work with ACLs.
 890  */
 891 STATIC void
 892 xfs_acl_filter_mode(
 893         mode_t          mode,
 894         xfs_acl_t       *acl)
 895 {
 896         int             i, nomask = 1;
 897         xfs_acl_entry_t *ap;
 898         xfs_acl_entry_t *gap = NULL;
 899
 900         /*
 901          * Set ACL entries. POSIX1003.1eD16 requires that the MASK
 902          * be merged with GROUP entry, if there is a MASK.
 903          */
 904         for (ap = acl->acl_entry, i = 0; i < acl->acl_cnt; ap++, i++) {
 905                 switch (ap->ae_tag) {
 906                 case ACL_USER_OBJ:
 907                         ap->ae_perm &= (mode >> 6) & 0x7;
 908                         break;
 909                 case ACL_GROUP_OBJ:
 910                         gap = ap;
 911                         break;
 912                 case ACL_MASK:
 913                         nomask = 0;
 914                         ap->ae_perm &= (mode >> 3) & 0x7;
 915                         break;
 916                 case ACL_OTHER:
 917                         ap->ae_perm &= mode & 0x7;
 918                         break;
 919                 default:
 920                         break;
 921                 }
 922         }
 923         /* Set the ACL_GROUP_OBJ if there's no ACL_MASK */
 924         if (gap && nomask)
 925                 gap->ae_perm &= (mode >> 3) & 0x7;
 926 }