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_dir2.h"
  25 #include "xfs_bmap_btree.h"
  26 #include "xfs_alloc_btree.h"
  27 #include "xfs_ialloc_btree.h"
  28 #include "xfs_dir2_sf.h"
  29 #include "xfs_attr_sf.h"
  30 #include "xfs_dinode.h"
  31 #include "xfs_inode.h"
  32 #include "xfs_btree.h"
  33 #include "xfs_acl.h"
  34 #include "xfs_attr.h"
  35 #include "xfs_vnodeops.h"
  36
  37 #include <linux/capability.h>
  38 #include <linux/posix_acl_xattr.h>
  39
  40 STATIC int      xfs_acl_setmode(bhv_vnode_t *, xfs_acl_t *, int *);
  41 STATIC void     xfs_acl_filter_mode(mode_t, xfs_acl_t *);
  42 STATIC void     xfs_acl_get_endian(xfs_acl_t *);
  43 STATIC int      xfs_acl_access(uid_t, gid_t, xfs_acl_t *, mode_t, cred_t *);
  44 STATIC int      xfs_acl_invalid(xfs_acl_t *);
  45 STATIC void     xfs_acl_sync_mode(mode_t, xfs_acl_t *);
  46 STATIC void     xfs_acl_get_attr(bhv_vnode_t *, xfs_acl_t *, int, int, int *);
  47 STATIC void     xfs_acl_set_attr(bhv_vnode_t *, xfs_acl_t *, int, int *);
  48 STATIC int      xfs_acl_allow_set(bhv_vnode_t *, int);
  49
  50 kmem_zone_t *xfs_acl_zone;
  51
  52
  53 /*
  54  * Test for existence of access ACL attribute as efficiently as possible.
  55  */
  56 int
  57 xfs_acl_vhasacl_access(
  58         bhv_vnode_t     *vp)
  59 {
  60         int             error;
  61
  62         xfs_acl_get_attr(vp, NULL, _ACL_TYPE_ACCESS, ATTR_KERNOVAL, &error);
  63         return (error == 0);
  64 }
  65
  66 /*
  67  * Test for existence of default ACL attribute as efficiently as possible.
  68  */
  69 int
  70 xfs_acl_vhasacl_default(
  71         bhv_vnode_t     *vp)
  72 {
  73         int             error;
  74
  75         if (!S_ISDIR(vp->i_mode))
  76                 return 0;
  77         xfs_acl_get_attr(vp, NULL, _ACL_TYPE_DEFAULT, ATTR_KERNOVAL, &error);
  78         return (error == 0);
  79 }
  80
  81 /*
  82  * Convert from extended attribute representation to in-memory for XFS.
  83  */
  84 STATIC int
  85 posix_acl_xattr_to_xfs(
  86         posix_acl_xattr_header  *src,
  87         size_t                  size,
  88         xfs_acl_t               *dest)
  89 {
  90         posix_acl_xattr_entry   *src_entry;
  91         xfs_acl_entry_t         *dest_entry;
  92         int                     n;
  93
  94         if (!src || !dest)
  95                 return EINVAL;
  96
  97         if (size < sizeof(posix_acl_xattr_header))
  98                 return EINVAL;
  99
 100         if (src->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
 101                 return EOPNOTSUPP;
 102
 103         memset(dest, 0, sizeof(xfs_acl_t));
 104         dest->acl_cnt = posix_acl_xattr_count(size);
 105         if (dest->acl_cnt < 0 || dest->acl_cnt > XFS_ACL_MAX_ENTRIES)
 106                 return EINVAL;
 107
 108         /*
 109          * acl_set_file(3) may request that we set default ACLs with
 110          * zero length -- defend (gracefully) against that here.
 111          */
 112         if (!dest->acl_cnt)
 113                 return 0;
 114
 115         src_entry = (posix_acl_xattr_entry *)((char *)src + sizeof(*src));
 116         dest_entry = &dest->acl_entry[0];
 117
 118         for (n = 0; n < dest->acl_cnt; n++, src_entry++, dest_entry++) {
 119                 dest_entry->ae_perm = le16_to_cpu(src_entry->e_perm);
 120                 if (_ACL_PERM_INVALID(dest_entry->ae_perm))
 121                         return EINVAL;
 122                 dest_entry->ae_tag  = le16_to_cpu(src_entry->e_tag);
 123                 switch(dest_entry->ae_tag) {
 124                 case ACL_USER:
 125                 case ACL_GROUP:
 126                         dest_entry->ae_id = le32_to_cpu(src_entry->e_id);
 127                         break;
 128                 case ACL_USER_OBJ:
 129                 case ACL_GROUP_OBJ:
 130                 case ACL_MASK:
 131                 case ACL_OTHER:
 132                         dest_entry->ae_id = ACL_UNDEFINED_ID;
 133                         break;
 134                 default:
 135                         return EINVAL;
 136                 }
 137         }
 138         if (xfs_acl_invalid(dest))
 139                 return EINVAL;
 140
 141         return 0;
 142 }
 143
 144 /*
 145  * Comparison function called from xfs_sort().
 146  * Primary key is ae_tag, secondary key is ae_id.
 147  */
 148 STATIC int
 149 xfs_acl_entry_compare(
 150         const void      *va,
 151         const void      *vb)
 152 {
 153         xfs_acl_entry_t *a = (xfs_acl_entry_t *)va,
 154                         *b = (xfs_acl_entry_t *)vb;
 155
 156         if (a->ae_tag == b->ae_tag)
 157                 return (a->ae_id - b->ae_id);
 158         return (a->ae_tag - b->ae_tag);
 159 }
 160
 161 /*
 162  * Convert from in-memory XFS to extended attribute representation.
 163  */
 164 STATIC int
 165 posix_acl_xfs_to_xattr(
 166         xfs_acl_t               *src,
 167         posix_acl_xattr_header  *dest,
 168         size_t                  size)
 169 {
 170         int                     n;
 171         size_t                  new_size = posix_acl_xattr_size(src->acl_cnt);
 172         posix_acl_xattr_entry   *dest_entry;
 173         xfs_acl_entry_t         *src_entry;
 174
 175         if (size < new_size)
 176                 return -ERANGE;
 177
 178         /* Need to sort src XFS ACL by <ae_tag,ae_id> */
 179         xfs_sort(src->acl_entry, src->acl_cnt, sizeof(src->acl_entry[0]),
 180                  xfs_acl_entry_compare);
 181
 182         dest->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
 183         dest_entry = &dest->a_entries[0];
 184         src_entry = &src->acl_entry[0];
 185         for (n = 0; n < src->acl_cnt; n++, dest_entry++, src_entry++) {
 186                 dest_entry->e_perm = cpu_to_le16(src_entry->ae_perm);
 187                 if (_ACL_PERM_INVALID(src_entry->ae_perm))
 188                         return -EINVAL;
 189                 dest_entry->e_tag  = cpu_to_le16(src_entry->ae_tag);
 190                 switch (src_entry->ae_tag) {
 191                 case ACL_USER:
 192                 case ACL_GROUP:
 193                         dest_entry->e_id = cpu_to_le32(src_entry->ae_id);
 194                                 break;
 195                 case ACL_USER_OBJ:
 196                 case ACL_GROUP_OBJ:
 197                 case ACL_MASK:
 198                 case ACL_OTHER:
 199                         dest_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
 200                         break;
 201                 default:
 202                         return -EINVAL;
 203                 }
 204         }
 205         return new_size;
 206 }
 207
 208 int
 209 xfs_acl_vget(
 210         bhv_vnode_t     *vp,
 211         void            *acl,
 212         size_t          size,
 213         int             kind)
 214 {
 215         int                     error;
 216         xfs_acl_t               *xfs_acl = NULL;
 217         posix_acl_xattr_header  *ext_acl = acl;
 218         int                     flags = 0;
 219
 220         VN_HOLD(vp);
 221         if(size) {
 222                 if (!(_ACL_ALLOC(xfs_acl))) {
 223                         error = ENOMEM;
 224                         goto out;
 225                 }
 226                 memset(xfs_acl, 0, sizeof(xfs_acl_t));
 227         } else
 228                 flags = ATTR_KERNOVAL;
 229
 230         xfs_acl_get_attr(vp, xfs_acl, kind, flags, &error);
 231         if (error)
 232                 goto out;
 233
 234         if (!size) {
 235                 error = -posix_acl_xattr_size(XFS_ACL_MAX_ENTRIES);
 236         } else {
 237                 if (xfs_acl_invalid(xfs_acl)) {
 238                         error = EINVAL;
 239                         goto out;
 240                 }
 241                 if (kind == _ACL_TYPE_ACCESS)
 242                         xfs_acl_sync_mode(xfs_vtoi(vp)->i_d.di_mode, xfs_acl);
 243                 error = -posix_acl_xfs_to_xattr(xfs_acl, ext_acl, size);
 244         }
 245 out:
 246         VN_RELE(vp);
 247         if(xfs_acl)
 248                 _ACL_FREE(xfs_acl);
 249         return -error;
 250 }
 251
 252 int
 253 xfs_acl_vremove(
 254         bhv_vnode_t     *vp,
 255         int             kind)
 256 {
 257         int             error;
 258
 259         VN_HOLD(vp);
 260         error = xfs_acl_allow_set(vp, kind);
 261         if (!error) {
 262                 error = xfs_attr_remove(xfs_vtoi(vp),
 263                                                 kind == _ACL_TYPE_DEFAULT?
 264                                                 SGI_ACL_DEFAULT: SGI_ACL_FILE,
 265                                                 ATTR_ROOT);
 266                 if (error == ENOATTR)
 267                         error = 0;      /* 'scool */
 268         }
 269         VN_RELE(vp);
 270         return -error;
 271 }
 272
 273 int
 274 xfs_acl_vset(
 275         bhv_vnode_t             *vp,
 276         void                    *acl,
 277         size_t                  size,
 278         int                     kind)
 279 {
 280         posix_acl_xattr_header  *ext_acl = acl;
 281         xfs_acl_t               *xfs_acl;
 282         int                     error;
 283         int                     basicperms = 0; /* more than std unix perms? */
 284
 285         if (!acl)
 286                 return -EINVAL;
 287
 288         if (!(_ACL_ALLOC(xfs_acl)))
 289                 return -ENOMEM;
 290
 291         error = posix_acl_xattr_to_xfs(ext_acl, size, xfs_acl);
 292         if (error) {
 293                 _ACL_FREE(xfs_acl);
 294                 return -error;
 295         }
 296         if (!xfs_acl->acl_cnt) {
 297                 _ACL_FREE(xfs_acl);
 298                 return 0;
 299         }
 300
 301         VN_HOLD(vp);
 302         error = xfs_acl_allow_set(vp, kind);
 303
 304         /* Incoming ACL exists, set file mode based on its value */
 305         if (!error && kind == _ACL_TYPE_ACCESS)
 306                 error = xfs_acl_setmode(vp, xfs_acl, &basicperms);
 307
 308         if (error)
 309                 goto out;
 310
 311         /*
 312          * If we have more than std unix permissions, set up the actual attr.
 313          * Otherwise, delete any existing attr.  This prevents us from
 314          * having actual attrs for permissions that can be stored in the
 315          * standard permission bits.
 316          */
 317         if (!basicperms) {
 318                 xfs_acl_set_attr(vp, xfs_acl, kind, &error);
 319         } else {
 320                 error = -xfs_acl_vremove(vp, _ACL_TYPE_ACCESS);
 321         }
 322
 323 out:
 324         VN_RELE(vp);
 325         _ACL_FREE(xfs_acl);
 326         return -error;
 327 }
 328
 329 int
 330 xfs_acl_iaccess(
 331         xfs_inode_t     *ip,
 332         mode_t          mode,
 333         cred_t          *cr)
 334 {
 335         xfs_acl_t       *acl;
 336         int             rval;
 337         struct xfs_name acl_name = {SGI_ACL_FILE, SGI_ACL_FILE_SIZE};
 338
 339         if (!(_ACL_ALLOC(acl)))
 340                 return -1;
 341
 342         /* If the file has no ACL return -1. */
 343         rval = sizeof(xfs_acl_t);
 344         if (xfs_attr_fetch(ip, &acl_name, (char *)acl, &rval,
 345                                         ATTR_ROOT | ATTR_KERNACCESS)) {
 346                 _ACL_FREE(acl);
 347                 return -1;
 348         }
 349         xfs_acl_get_endian(acl);
 350
 351         /* If the file has an empty ACL return -1. */
 352         if (acl->acl_cnt == XFS_ACL_NOT_PRESENT) {
 353                 _ACL_FREE(acl);
 354                 return -1;
 355         }
 356
 357         /* Synchronize ACL with mode bits */
 358         xfs_acl_sync_mode(ip->i_d.di_mode, acl);
 359
 360         rval = xfs_acl_access(ip->i_d.di_uid, ip->i_d.di_gid, acl, mode, cr);
 361         _ACL_FREE(acl);
 362         return rval;
 363 }
 364
 365 STATIC int
 366 xfs_acl_allow_set(
 367         bhv_vnode_t     *vp,
 368         int             kind)
 369 {
 370         if (vp->i_flags & (S_IMMUTABLE|S_APPEND))
 371                 return EPERM;
 372         if (kind == _ACL_TYPE_DEFAULT && !S_ISDIR(vp->i_mode))
 373                 return ENOTDIR;
 374         if (vp->i_sb->s_flags & MS_RDONLY)
 375                 return EROFS;
 376         if (xfs_vtoi(vp)->i_d.di_uid != current->fsuid && !capable(CAP_FOWNER))
 377                 return EPERM;
 378         return 0;
 379 }
 380
 381 /*
 382  * Note: cr is only used here for the capability check if the ACL test fails.
 383  *       It is not used to find out the credentials uid or groups etc, as was
 384  *       done in IRIX. It is assumed that the uid and groups for the current
 385  *       thread are taken from "current" instead of the cr parameter.
 386  */
 387 STATIC int
 388 xfs_acl_access(
 389         uid_t           fuid,
 390         gid_t           fgid,
 391         xfs_acl_t       *fap,
 392         mode_t          md,
 393         cred_t          *cr)
 394 {
 395         xfs_acl_entry_t matched;
 396         int             i, allows;
 397         int             maskallows = -1;        /* true, but not 1, either */
 398         int             seen_userobj = 0;
 399
 400         matched.ae_tag = 0;     /* Invalid type */
 401         matched.ae_perm = 0;
 402
 403         for (i = 0; i < fap->acl_cnt; i++) {
 404                 /*
 405                  * Break out if we've got a user_obj entry or
 406                  * a user entry and the mask (and have processed USER_OBJ)
 407                  */
 408                 if (matched.ae_tag == ACL_USER_OBJ)
 409                         break;
 410                 if (matched.ae_tag == ACL_USER) {
 411                         if (maskallows != -1 && seen_userobj)
 412                                 break;
 413                         if (fap->acl_entry[i].ae_tag != ACL_MASK &&
 414                             fap->acl_entry[i].ae_tag != ACL_USER_OBJ)
 415                                 continue;
 416                 }
 417                 /* True if this entry allows the requested access */
 418                 allows = ((fap->acl_entry[i].ae_perm & md) == md);
 419
 420                 switch (fap->acl_entry[i].ae_tag) {
 421                 case ACL_USER_OBJ:
 422                         seen_userobj = 1;
 423                         if (fuid != current->fsuid)
 424                                 continue;
 425                         matched.ae_tag = ACL_USER_OBJ;
 426                         matched.ae_perm = allows;
 427                         break;
 428                 case ACL_USER:
 429                         if (fap->acl_entry[i].ae_id != current->fsuid)
 430                                 continue;
 431                         matched.ae_tag = ACL_USER;
 432                         matched.ae_perm = allows;
 433                         break;
 434                 case ACL_GROUP_OBJ:
 435                         if ((matched.ae_tag == ACL_GROUP_OBJ ||
 436                             matched.ae_tag == ACL_GROUP) && !allows)
 437                                 continue;
 438                         if (!in_group_p(fgid))
 439                                 continue;
 440                         matched.ae_tag = ACL_GROUP_OBJ;
 441                         matched.ae_perm = allows;
 442                         break;
 443                 case ACL_GROUP:
 444                         if ((matched.ae_tag == ACL_GROUP_OBJ ||
 445                             matched.ae_tag == ACL_GROUP) && !allows)
 446                                 continue;
 447                         if (!in_group_p(fap->acl_entry[i].ae_id))
 448                                 continue;
 449                         matched.ae_tag = ACL_GROUP;
 450                         matched.ae_perm = allows;
 451                         break;
 452                 case ACL_MASK:
 453                         maskallows = allows;
 454                         break;
 455                 case ACL_OTHER:
 456                         if (matched.ae_tag != 0)
 457                                 continue;
 458                         matched.ae_tag = ACL_OTHER;
 459                         matched.ae_perm = allows;
 460                         break;
 461                 }
 462         }
 463         /*
 464          * First possibility is that no matched entry allows access.
 465          * The capability to override DAC may exist, so check for it.
 466          */
 467         switch (matched.ae_tag) {
 468         case ACL_OTHER:
 469         case ACL_USER_OBJ:
 470                 if (matched.ae_perm)
 471                         return 0;
 472                 break;
 473         case ACL_USER:
 474         case ACL_GROUP_OBJ:
 475         case ACL_GROUP:
 476                 if (maskallows && matched.ae_perm)
 477                         return 0;
 478                 break;
 479         case 0:
 480                 break;
 481         }
 482
 483         /* EACCES tells generic_permission to check for capability overrides */
 484         return EACCES;
 485 }
 486
 487 /*
 488  * ACL validity checker.
 489  *   This acl validation routine checks each ACL entry read in makes sense.
 490  */
 491 STATIC int
 492 xfs_acl_invalid(
 493         xfs_acl_t       *aclp)
 494 {
 495         xfs_acl_entry_t *entry, *e;
 496         int             user = 0, group = 0, other = 0, mask = 0;
 497         int             mask_required = 0;
 498         int             i, j;
 499
 500         if (!aclp)
 501                 goto acl_invalid;
 502
 503         if (aclp->acl_cnt > XFS_ACL_MAX_ENTRIES)
 504                 goto acl_invalid;
 505
 506         for (i = 0; i < aclp->acl_cnt; i++) {
 507                 entry = &aclp->acl_entry[i];
 508                 switch (entry->ae_tag) {
 509                 case ACL_USER_OBJ:
 510                         if (user++)
 511                                 goto acl_invalid;
 512                         break;
 513                 case ACL_GROUP_OBJ:
 514                         if (group++)
 515                                 goto acl_invalid;
 516                         break;
 517                 case ACL_OTHER:
 518                         if (other++)
 519                                 goto acl_invalid;
 520                         break;
 521                 case ACL_USER:
 522                 case ACL_GROUP:
 523                         for (j = i + 1; j < aclp->acl_cnt; j++) {
 524                                 e = &aclp->acl_entry[j];
 525                                 if (e->ae_id == entry->ae_id &&
 526                                     e->ae_tag == entry->ae_tag)
 527                                         goto acl_invalid;
 528                         }
 529                         mask_required++;
 530                         break;
 531                 case ACL_MASK:
 532                         if (mask++)
 533                                 goto acl_invalid;
 534                         break;
 535                 default:
 536                         goto acl_invalid;
 537                 }
 538         }
 539         if (!user || !group || !other || (mask_required && !mask))
 540                 goto acl_invalid;
 541         else
 542                 return 0;
 543 acl_invalid:
 544         return EINVAL;
 545 }
 546
 547 /*
 548  * Do ACL endian conversion.
 549  */
 550 STATIC void
 551 xfs_acl_get_endian(
 552         xfs_acl_t       *aclp)
 553 {
 554         xfs_acl_entry_t *ace, *end;
 555
 556         INT_SET(aclp->acl_cnt, ARCH_CONVERT, aclp->acl_cnt);
 557         end = &aclp->acl_entry[0]+aclp->acl_cnt;
 558         for (ace = &aclp->acl_entry[0]; ace < end; ace++) {
 559                 INT_SET(ace->ae_tag, ARCH_CONVERT, ace->ae_tag);
 560                 INT_SET(ace->ae_id, ARCH_CONVERT, ace->ae_id);
 561                 INT_SET(ace->ae_perm, ARCH_CONVERT, ace->ae_perm);
 562         }
 563 }
 564
 565 /*
 566  * Get the ACL from the EA and do endian conversion.
 567  */
 568 STATIC void
 569 xfs_acl_get_attr(
 570         bhv_vnode_t     *vp,
 571         xfs_acl_t       *aclp,
 572         int             kind,
 573         int             flags,
 574         int             *error)
 575 {
 576         int             len = sizeof(xfs_acl_t);
 577
 578         ASSERT((flags & ATTR_KERNOVAL) ? (aclp == NULL) : 1);
 579         flags |= ATTR_ROOT;
 580         *error = xfs_attr_get(xfs_vtoi(vp),
 581                                         kind == _ACL_TYPE_ACCESS ?
 582                                         SGI_ACL_FILE : SGI_ACL_DEFAULT,
 583                                         (char *)aclp, &len, flags);
 584         if (*error || (flags & ATTR_KERNOVAL))
 585                 return;
 586         xfs_acl_get_endian(aclp);
 587 }
 588
 589 /*
 590  * Set the EA with the ACL and do endian conversion.
 591  */
 592 STATIC void
 593 xfs_acl_set_attr(
 594         bhv_vnode_t     *vp,
 595         xfs_acl_t       *aclp,
 596         int             kind,
 597         int             *error)
 598 {
 599         xfs_acl_entry_t *ace, *newace, *end;
 600         xfs_acl_t       *newacl;
 601         int             len;
 602
 603         if (!(_ACL_ALLOC(newacl))) {
 604                 *error = ENOMEM;
 605                 return;
 606         }
 607
 608         len = sizeof(xfs_acl_t) -
 609               (sizeof(xfs_acl_entry_t) * (XFS_ACL_MAX_ENTRIES - aclp->acl_cnt));
 610         end = &aclp->acl_entry[0]+aclp->acl_cnt;
 611         for (ace = &aclp->acl_entry[0], newace = &newacl->acl_entry[0];
 612              ace < end;
 613              ace++, newace++) {
 614                 INT_SET(newace->ae_tag, ARCH_CONVERT, ace->ae_tag);
 615                 INT_SET(newace->ae_id, ARCH_CONVERT, ace->ae_id);
 616                 INT_SET(newace->ae_perm, ARCH_CONVERT, ace->ae_perm);
 617         }
 618         INT_SET(newacl->acl_cnt, ARCH_CONVERT, aclp->acl_cnt);
 619         *error = xfs_attr_set(xfs_vtoi(vp),
 620                                 kind == _ACL_TYPE_ACCESS ?
 621                                 SGI_ACL_FILE: SGI_ACL_DEFAULT,
 622                                 (char *)newacl, len, ATTR_ROOT);
 623         _ACL_FREE(newacl);
 624 }
 625
 626 int
 627 xfs_acl_vtoacl(
 628         bhv_vnode_t     *vp,
 629         xfs_acl_t       *access_acl,
 630         xfs_acl_t       *default_acl)
 631 {
 632         int             error = 0;
 633
 634         if (access_acl) {
 635                 /*
 636                  * Get the Access ACL and the mode.  If either cannot
 637                  * be obtained for some reason, invalidate the access ACL.
 638                  */
 639                 xfs_acl_get_attr(vp, access_acl, _ACL_TYPE_ACCESS, 0, &error);
 640                 if (error)
 641                         access_acl->acl_cnt = XFS_ACL_NOT_PRESENT;
 642                 else /* We have a good ACL and the file mode, synchronize. */
 643                         xfs_acl_sync_mode(xfs_vtoi(vp)->i_d.di_mode, access_acl);
 644         }
 645
 646         if (default_acl) {
 647                 xfs_acl_get_attr(vp, default_acl, _ACL_TYPE_DEFAULT, 0, &error);
 648                 if (error)
 649                         default_acl->acl_cnt = XFS_ACL_NOT_PRESENT;
 650         }
 651         return error;
 652 }
 653
 654 /*
 655  * This function retrieves the parent directory's acl, processes it
 656  * and lets the child inherit the acl(s) that it should.
 657  */
 658 int
 659 xfs_acl_inherit(
 660         bhv_vnode_t     *vp,
 661         mode_t          mode,
 662         xfs_acl_t       *pdaclp)
 663 {
 664         xfs_acl_t       *cacl;
 665         int             error = 0;
 666         int             basicperms = 0;
 667
 668         /*
 669          * If the parent does not have a default ACL, or it's an
 670          * invalid ACL, we're done.
 671          */
 672         if (!vp)
 673                 return 0;
 674         if (!pdaclp || xfs_acl_invalid(pdaclp))
 675                 return 0;
 676
 677         /*
 678          * Copy the default ACL of the containing directory to
 679          * the access ACL of the new file and use the mode that
 680          * was passed in to set up the correct initial values for
 681          * the u::,g::[m::], and o:: entries.  This is what makes
 682          * umask() "work" with ACL's.
 683          */
 684
 685         if (!(_ACL_ALLOC(cacl)))
 686                 return ENOMEM;
 687
 688         memcpy(cacl, pdaclp, sizeof(xfs_acl_t));
 689         xfs_acl_filter_mode(mode, cacl);
 690         error = xfs_acl_setmode(vp, cacl, &basicperms);
 691         if (error)
 692                 goto out_error;
 693
 694         /*
 695          * Set the Default and Access ACL on the file.  The mode is already
 696          * set on the file, so we don't need to worry about that.
 697          *
 698          * If the new file is a directory, its default ACL is a copy of
 699          * the containing directory's default ACL.
 700          */
 701         if (S_ISDIR(vp->i_mode))
 702                 xfs_acl_set_attr(vp, pdaclp, _ACL_TYPE_DEFAULT, &error);
 703         if (!error && !basicperms)
 704                 xfs_acl_set_attr(vp, cacl, _ACL_TYPE_ACCESS, &error);
 705 out_error:
 706         _ACL_FREE(cacl);
 707         return error;
 708 }
 709
 710 /*
 711  * Set up the correct mode on the file based on the supplied ACL.  This
 712  * makes sure that the mode on the file reflects the state of the
 713  * u::,g::[m::], and o:: entries in the ACL.  Since the mode is where
 714  * the ACL is going to get the permissions for these entries, we must
 715  * synchronize the mode whenever we set the ACL on a file.
 716  */
 717 STATIC int
 718 xfs_acl_setmode(
 719         bhv_vnode_t     *vp,
 720         xfs_acl_t       *acl,
 721         int             *basicperms)
 722 {
 723         bhv_vattr_t     va;
 724         xfs_acl_entry_t *ap;
 725         xfs_acl_entry_t *gap = NULL;
 726         int             i, nomask = 1;
 727
 728         *basicperms = 1;
 729
 730         if (acl->acl_cnt == XFS_ACL_NOT_PRESENT)
 731                 return 0;
 732
 733         /*
 734          * Copy the u::, g::, o::, and m:: bits from the ACL into the
 735          * mode.  The m:: bits take precedence over the g:: bits.
 736          */
 737         va.va_mask = XFS_AT_MODE;
 738         va.va_mode = xfs_vtoi(vp)->i_d.di_mode;
 739         va.va_mode &= ~(S_IRWXU|S_IRWXG|S_IRWXO);
 740         ap = acl->acl_entry;
 741         for (i = 0; i < acl->acl_cnt; ++i) {
 742                 switch (ap->ae_tag) {
 743                 case ACL_USER_OBJ:
 744                         va.va_mode |= ap->ae_perm << 6;
 745                         break;
 746                 case ACL_GROUP_OBJ:
 747                         gap = ap;
 748                         break;
 749                 case ACL_MASK:  /* more than just standard modes */
 750                         nomask = 0;
 751                         va.va_mode |= ap->ae_perm << 3;
 752                         *basicperms = 0;
 753                         break;
 754                 case ACL_OTHER:
 755                         va.va_mode |= ap->ae_perm;
 756                         break;
 757                 default:        /* more than just standard modes */
 758                         *basicperms = 0;
 759                         break;
 760                 }
 761                 ap++;
 762         }
 763
 764         /* Set the group bits from ACL_GROUP_OBJ if there's no ACL_MASK */
 765         if (gap && nomask)
 766                 va.va_mode |= gap->ae_perm << 3;
 767
 768         return xfs_setattr(xfs_vtoi(vp), &va, 0, sys_cred);
 769 }
 770
 771 /*
 772  * The permissions for the special ACL entries (u::, g::[m::], o::) are
 773  * actually stored in the file mode (if there is both a group and a mask,
 774  * the group is stored in the ACL entry and the mask is stored on the file).
 775  * This allows the mode to remain automatically in sync with the ACL without
 776  * the need for a call-back to the ACL system at every point where the mode
 777  * could change.  This function takes the permissions from the specified mode
 778  * and places it in the supplied ACL.
 779  *
 780  * This implementation draws its validity from the fact that, when the ACL
 781  * was assigned, the mode was copied from the ACL.
 782  * If the mode did not change, therefore, the mode remains exactly what was
 783  * taken from the special ACL entries at assignment.
 784  * If a subsequent chmod() was done, the POSIX spec says that the change in
 785  * mode must cause an update to the ACL seen at user level and used for
 786  * access checks.  Before and after a mode change, therefore, the file mode
 787  * most accurately reflects what the special ACL entries should permit/deny.
 788  *
 789  * CAVEAT: If someone sets the SGI_ACL_FILE attribute directly,
 790  *         the existing mode bits will override whatever is in the
 791  *         ACL. Similarly, if there is a pre-existing ACL that was
 792  *         never in sync with its mode (owing to a bug in 6.5 and
 793  *         before), it will now magically (or mystically) be
 794  *         synchronized.  This could cause slight astonishment, but
 795  *         it is better than inconsistent permissions.
 796  *
 797  * The supplied ACL is a template that may contain any combination
 798  * of special entries.  These are treated as place holders when we fill
 799  * out the ACL.  This routine does not add or remove special entries, it
 800  * simply unites each special entry with its associated set of permissions.
 801  */
 802 STATIC void
 803 xfs_acl_sync_mode(
 804         mode_t          mode,
 805         xfs_acl_t       *acl)
 806 {
 807         int             i, nomask = 1;
 808         xfs_acl_entry_t *ap;
 809         xfs_acl_entry_t *gap = NULL;
 810
 811         /*
 812          * Set ACL entries. POSIX1003.1eD16 requires that the MASK
 813          * be set instead of the GROUP entry, if there is a MASK.
 814          */
 815         for (ap = acl->acl_entry, i = 0; i < acl->acl_cnt; ap++, i++) {
 816                 switch (ap->ae_tag) {
 817                 case ACL_USER_OBJ:
 818                         ap->ae_perm = (mode >> 6) & 0x7;
 819                         break;
 820                 case ACL_GROUP_OBJ:
 821                         gap = ap;
 822                         break;
 823                 case ACL_MASK:
 824                         nomask = 0;
 825                         ap->ae_perm = (mode >> 3) & 0x7;
 826                         break;
 827                 case ACL_OTHER:
 828                         ap->ae_perm = mode & 0x7;
 829                         break;
 830                 default:
 831                         break;
 832                 }
 833         }
 834         /* Set the ACL_GROUP_OBJ if there's no ACL_MASK */
 835         if (gap && nomask)
 836                 gap->ae_perm = (mode >> 3) & 0x7;
 837 }
 838
 839 /*
 840  * When inheriting an Access ACL from a directory Default ACL,
 841  * the ACL bits are set to the intersection of the ACL default
 842  * permission bits and the file permission bits in mode. If there
 843  * are no permission bits on the file then we must not give them
 844  * the ACL. This is what what makes umask() work with ACLs.
 845  */
 846 STATIC void
 847 xfs_acl_filter_mode(
 848         mode_t          mode,
 849         xfs_acl_t       *acl)
 850 {
 851         int             i, nomask = 1;
 852         xfs_acl_entry_t *ap;
 853         xfs_acl_entry_t *gap = NULL;
 854
 855         /*
 856          * Set ACL entries. POSIX1003.1eD16 requires that the MASK
 857          * be merged with GROUP entry, if there is a MASK.
 858          */
 859         for (ap = acl->acl_entry, i = 0; i < acl->acl_cnt; ap++, i++) {
 860                 switch (ap->ae_tag) {
 861                 case ACL_USER_OBJ:
 862                         ap->ae_perm &= (mode >> 6) & 0x7;
 863                         break;
 864                 case ACL_GROUP_OBJ:
 865                         gap = ap;
 866                         break;
 867                 case ACL_MASK:
 868                         nomask = 0;
 869                         ap->ae_perm &= (mode >> 3) & 0x7;
 870                         break;
 871                 case ACL_OTHER:
 872                         ap->ae_perm &= mode & 0x7;
 873                         break;
 874                 default:
 875                         break;
 876                 }
 877         }
 878         /* Set the ACL_GROUP_OBJ if there's no ACL_MASK */
 879         if (gap && nomask)
 880                 gap->ae_perm &= (mode >> 3) & 0x7;
 881 }