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 (!VN_ISDIR(vp))
  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                         bhv_vattr_t     va;
 243
 244                         va.va_mask = XFS_AT_MODE;
 245                         error = xfs_getattr(xfs_vtoi(vp), &va, 0);
 246                         if (error)
 247                                 goto out;
 248                         xfs_acl_sync_mode(va.va_mode, xfs_acl);
 249                 }
 250                 error = -posix_acl_xfs_to_xattr(xfs_acl, ext_acl, size);
 251         }
 252 out:
 253         VN_RELE(vp);
 254         if(xfs_acl)
 255                 _ACL_FREE(xfs_acl);
 256         return -error;
 257 }
 258
 259 int
 260 xfs_acl_vremove(
 261         bhv_vnode_t     *vp,
 262         int             kind)
 263 {
 264         int             error;
 265
 266         VN_HOLD(vp);
 267         error = xfs_acl_allow_set(vp, kind);
 268         if (!error) {
 269                 error = xfs_attr_remove(xfs_vtoi(vp),
 270                                                 kind == _ACL_TYPE_DEFAULT?
 271                                                 SGI_ACL_DEFAULT: SGI_ACL_FILE,
 272                                                 ATTR_ROOT);
 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         bhv_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         bhv_vnode_t     *vp,
 373         int             kind)
 374 {
 375         xfs_inode_t     *ip = xfs_vtoi(vp);
 376         bhv_vattr_t     va;
 377         int             error;
 378
 379         if (vp->i_flags & (S_IMMUTABLE|S_APPEND))
 380                 return EPERM;
 381         if (kind == _ACL_TYPE_DEFAULT && !VN_ISDIR(vp))
 382                 return ENOTDIR;
 383         if (vp->i_sb->s_flags & MS_RDONLY)
 384                 return EROFS;
 385         va.va_mask = XFS_AT_UID;
 386         error = xfs_getattr(ip, &va, 0);
 387         if (error)
 388                 return error;
 389         if (va.va_uid != current->fsuid && !capable(CAP_FOWNER))
 390                 return EPERM;
 391         return error;
 392 }
 393
 394 /*
 395  * Note: cr is only used here for the capability check if the ACL test fails.
 396  *       It is not used to find out the credentials uid or groups etc, as was
 397  *       done in IRIX. It is assumed that the uid and groups for the current
 398  *       thread are taken from "current" instead of the cr parameter.
 399  */
 400 STATIC int
 401 xfs_acl_access(
 402         uid_t           fuid,
 403         gid_t           fgid,
 404         xfs_acl_t       *fap,
 405         mode_t          md,
 406         cred_t          *cr)
 407 {
 408         xfs_acl_entry_t matched;
 409         int             i, allows;
 410         int             maskallows = -1;        /* true, but not 1, either */
 411         int             seen_userobj = 0;
 412
 413         matched.ae_tag = 0;     /* Invalid type */
 414         matched.ae_perm = 0;
 415
 416         for (i = 0; i < fap->acl_cnt; i++) {
 417                 /*
 418                  * Break out if we've got a user_obj entry or
 419                  * a user entry and the mask (and have processed USER_OBJ)
 420                  */
 421                 if (matched.ae_tag == ACL_USER_OBJ)
 422                         break;
 423                 if (matched.ae_tag == ACL_USER) {
 424                         if (maskallows != -1 && seen_userobj)
 425                                 break;
 426                         if (fap->acl_entry[i].ae_tag != ACL_MASK &&
 427                             fap->acl_entry[i].ae_tag != ACL_USER_OBJ)
 428                                 continue;
 429                 }
 430                 /* True if this entry allows the requested access */
 431                 allows = ((fap->acl_entry[i].ae_perm & md) == md);
 432
 433                 switch (fap->acl_entry[i].ae_tag) {
 434                 case ACL_USER_OBJ:
 435                         seen_userobj = 1;
 436                         if (fuid != current->fsuid)
 437                                 continue;
 438                         matched.ae_tag = ACL_USER_OBJ;
 439                         matched.ae_perm = allows;
 440                         break;
 441                 case ACL_USER:
 442                         if (fap->acl_entry[i].ae_id != current->fsuid)
 443                                 continue;
 444                         matched.ae_tag = ACL_USER;
 445                         matched.ae_perm = allows;
 446                         break;
 447                 case ACL_GROUP_OBJ:
 448                         if ((matched.ae_tag == ACL_GROUP_OBJ ||
 449                             matched.ae_tag == ACL_GROUP) && !allows)
 450                                 continue;
 451                         if (!in_group_p(fgid))
 452                                 continue;
 453                         matched.ae_tag = ACL_GROUP_OBJ;
 454                         matched.ae_perm = allows;
 455                         break;
 456                 case ACL_GROUP:
 457                         if ((matched.ae_tag == ACL_GROUP_OBJ ||
 458                             matched.ae_tag == ACL_GROUP) && !allows)
 459                                 continue;
 460                         if (!in_group_p(fap->acl_entry[i].ae_id))
 461                                 continue;
 462                         matched.ae_tag = ACL_GROUP;
 463                         matched.ae_perm = allows;
 464                         break;
 465                 case ACL_MASK:
 466                         maskallows = allows;
 467                         break;
 468                 case ACL_OTHER:
 469                         if (matched.ae_tag != 0)
 470                                 continue;
 471                         matched.ae_tag = ACL_OTHER;
 472                         matched.ae_perm = allows;
 473                         break;
 474                 }
 475         }
 476         /*
 477          * First possibility is that no matched entry allows access.
 478          * The capability to override DAC may exist, so check for it.
 479          */
 480         switch (matched.ae_tag) {
 481         case ACL_OTHER:
 482         case ACL_USER_OBJ:
 483                 if (matched.ae_perm)
 484                         return 0;
 485                 break;
 486         case ACL_USER:
 487         case ACL_GROUP_OBJ:
 488         case ACL_GROUP:
 489                 if (maskallows && matched.ae_perm)
 490                         return 0;
 491                 break;
 492         case 0:
 493                 break;
 494         }
 495
 496         /* EACCES tells generic_permission to check for capability overrides */
 497         return EACCES;
 498 }
 499
 500 /*
 501  * ACL validity checker.
 502  *   This acl validation routine checks each ACL entry read in makes sense.
 503  */
 504 STATIC int
 505 xfs_acl_invalid(
 506         xfs_acl_t       *aclp)
 507 {
 508         xfs_acl_entry_t *entry, *e;
 509         int             user = 0, group = 0, other = 0, mask = 0;
 510         int             mask_required = 0;
 511         int             i, j;
 512
 513         if (!aclp)
 514                 goto acl_invalid;
 515
 516         if (aclp->acl_cnt > XFS_ACL_MAX_ENTRIES)
 517                 goto acl_invalid;
 518
 519         for (i = 0; i < aclp->acl_cnt; i++) {
 520                 entry = &aclp->acl_entry[i];
 521                 switch (entry->ae_tag) {
 522                 case ACL_USER_OBJ:
 523                         if (user++)
 524                                 goto acl_invalid;
 525                         break;
 526                 case ACL_GROUP_OBJ:
 527                         if (group++)
 528                                 goto acl_invalid;
 529                         break;
 530                 case ACL_OTHER:
 531                         if (other++)
 532                                 goto acl_invalid;
 533                         break;
 534                 case ACL_USER:
 535                 case ACL_GROUP:
 536                         for (j = i + 1; j < aclp->acl_cnt; j++) {
 537                                 e = &aclp->acl_entry[j];
 538                                 if (e->ae_id == entry->ae_id &&
 539                                     e->ae_tag == entry->ae_tag)
 540                                         goto acl_invalid;
 541                         }
 542                         mask_required++;
 543                         break;
 544                 case ACL_MASK:
 545                         if (mask++)
 546                                 goto acl_invalid;
 547                         break;
 548                 default:
 549                         goto acl_invalid;
 550                 }
 551         }
 552         if (!user || !group || !other || (mask_required && !mask))
 553                 goto acl_invalid;
 554         else
 555                 return 0;
 556 acl_invalid:
 557         return EINVAL;
 558 }
 559
 560 /*
 561  * Do ACL endian conversion.
 562  */
 563 STATIC void
 564 xfs_acl_get_endian(
 565         xfs_acl_t       *aclp)
 566 {
 567         xfs_acl_entry_t *ace, *end;
 568
 569         INT_SET(aclp->acl_cnt, ARCH_CONVERT, aclp->acl_cnt);
 570         end = &aclp->acl_entry[0]+aclp->acl_cnt;
 571         for (ace = &aclp->acl_entry[0]; ace < end; ace++) {
 572                 INT_SET(ace->ae_tag, ARCH_CONVERT, ace->ae_tag);
 573                 INT_SET(ace->ae_id, ARCH_CONVERT, ace->ae_id);
 574                 INT_SET(ace->ae_perm, ARCH_CONVERT, ace->ae_perm);
 575         }
 576 }
 577
 578 /*
 579  * Get the ACL from the EA and do endian conversion.
 580  */
 581 STATIC void
 582 xfs_acl_get_attr(
 583         bhv_vnode_t     *vp,
 584         xfs_acl_t       *aclp,
 585         int             kind,
 586         int             flags,
 587         int             *error)
 588 {
 589         int             len = sizeof(xfs_acl_t);
 590
 591         ASSERT((flags & ATTR_KERNOVAL) ? (aclp == NULL) : 1);
 592         flags |= ATTR_ROOT;
 593         *error = xfs_attr_get(xfs_vtoi(vp),
 594                                         kind == _ACL_TYPE_ACCESS ?
 595                                         SGI_ACL_FILE : SGI_ACL_DEFAULT,
 596                                         (char *)aclp, &len, flags, sys_cred);
 597         if (*error || (flags & ATTR_KERNOVAL))
 598                 return;
 599         xfs_acl_get_endian(aclp);
 600 }
 601
 602 /*
 603  * Set the EA with the ACL and do endian conversion.
 604  */
 605 STATIC void
 606 xfs_acl_set_attr(
 607         bhv_vnode_t     *vp,
 608         xfs_acl_t       *aclp,
 609         int             kind,
 610         int             *error)
 611 {
 612         xfs_acl_entry_t *ace, *newace, *end;
 613         xfs_acl_t       *newacl;
 614         int             len;
 615
 616         if (!(_ACL_ALLOC(newacl))) {
 617                 *error = ENOMEM;
 618                 return;
 619         }
 620
 621         len = sizeof(xfs_acl_t) -
 622               (sizeof(xfs_acl_entry_t) * (XFS_ACL_MAX_ENTRIES - aclp->acl_cnt));
 623         end = &aclp->acl_entry[0]+aclp->acl_cnt;
 624         for (ace = &aclp->acl_entry[0], newace = &newacl->acl_entry[0];
 625              ace < end;
 626              ace++, newace++) {
 627                 INT_SET(newace->ae_tag, ARCH_CONVERT, ace->ae_tag);
 628                 INT_SET(newace->ae_id, ARCH_CONVERT, ace->ae_id);
 629                 INT_SET(newace->ae_perm, ARCH_CONVERT, ace->ae_perm);
 630         }
 631         INT_SET(newacl->acl_cnt, ARCH_CONVERT, aclp->acl_cnt);
 632         *error = xfs_attr_set(xfs_vtoi(vp),
 633                                 kind == _ACL_TYPE_ACCESS ?
 634                                 SGI_ACL_FILE: SGI_ACL_DEFAULT,
 635                                 (char *)newacl, len, ATTR_ROOT);
 636         _ACL_FREE(newacl);
 637 }
 638
 639 int
 640 xfs_acl_vtoacl(
 641         bhv_vnode_t     *vp,
 642         xfs_acl_t       *access_acl,
 643         xfs_acl_t       *default_acl)
 644 {
 645         bhv_vattr_t     va;
 646         int             error = 0;
 647
 648         if (access_acl) {
 649                 /*
 650                  * Get the Access ACL and the mode.  If either cannot
 651                  * be obtained for some reason, invalidate the access ACL.
 652                  */
 653                 xfs_acl_get_attr(vp, access_acl, _ACL_TYPE_ACCESS, 0, &error);
 654                 if (!error) {
 655                         /* Got the ACL, need the mode... */
 656                         va.va_mask = XFS_AT_MODE;
 657                         error = xfs_getattr(xfs_vtoi(vp), &va, 0);
 658                 }
 659
 660                 if (error)
 661                         access_acl->acl_cnt = XFS_ACL_NOT_PRESENT;
 662                 else /* We have a good ACL and the file mode, synchronize. */
 663                         xfs_acl_sync_mode(va.va_mode, access_acl);
 664         }
 665
 666         if (default_acl) {
 667                 xfs_acl_get_attr(vp, default_acl, _ACL_TYPE_DEFAULT, 0, &error);
 668                 if (error)
 669                         default_acl->acl_cnt = XFS_ACL_NOT_PRESENT;
 670         }
 671         return error;
 672 }
 673
 674 /*
 675  * This function retrieves the parent directory's acl, processes it
 676  * and lets the child inherit the acl(s) that it should.
 677  */
 678 int
 679 xfs_acl_inherit(
 680         bhv_vnode_t     *vp,
 681         mode_t          mode,
 682         xfs_acl_t       *pdaclp)
 683 {
 684         xfs_acl_t       *cacl;
 685         int             error = 0;
 686         int             basicperms = 0;
 687
 688         /*
 689          * If the parent does not have a default ACL, or it's an
 690          * invalid ACL, we're done.
 691          */
 692         if (!vp)
 693                 return 0;
 694         if (!pdaclp || xfs_acl_invalid(pdaclp))
 695                 return 0;
 696
 697         /*
 698          * Copy the default ACL of the containing directory to
 699          * the access ACL of the new file and use the mode that
 700          * was passed in to set up the correct initial values for
 701          * the u::,g::[m::], and o:: entries.  This is what makes
 702          * umask() "work" with ACL's.
 703          */
 704
 705         if (!(_ACL_ALLOC(cacl)))
 706                 return ENOMEM;
 707
 708         memcpy(cacl, pdaclp, sizeof(xfs_acl_t));
 709         xfs_acl_filter_mode(mode, cacl);
 710         xfs_acl_setmode(vp, cacl, &basicperms);
 711
 712         /*
 713          * Set the Default and Access ACL on the file.  The mode is already
 714          * set on the file, so we don't need to worry about that.
 715          *
 716          * If the new file is a directory, its default ACL is a copy of
 717          * the containing directory's default ACL.
 718          */
 719         if (VN_ISDIR(vp))
 720                 xfs_acl_set_attr(vp, pdaclp, _ACL_TYPE_DEFAULT, &error);
 721         if (!error && !basicperms)
 722                 xfs_acl_set_attr(vp, cacl, _ACL_TYPE_ACCESS, &error);
 723         _ACL_FREE(cacl);
 724         return error;
 725 }
 726
 727 /*
 728  * Set up the correct mode on the file based on the supplied ACL.  This
 729  * makes sure that the mode on the file reflects the state of the
 730  * u::,g::[m::], and o:: entries in the ACL.  Since the mode is where
 731  * the ACL is going to get the permissions for these entries, we must
 732  * synchronize the mode whenever we set the ACL on a file.
 733  */
 734 STATIC int
 735 xfs_acl_setmode(
 736         bhv_vnode_t     *vp,
 737         xfs_acl_t       *acl,
 738         int             *basicperms)
 739 {
 740         bhv_vattr_t     va;
 741         xfs_acl_entry_t *ap;
 742         xfs_acl_entry_t *gap = NULL;
 743         int             i, error, nomask = 1;
 744
 745         *basicperms = 1;
 746
 747         if (acl->acl_cnt == XFS_ACL_NOT_PRESENT)
 748                 return 0;
 749
 750         /*
 751          * Copy the u::, g::, o::, and m:: bits from the ACL into the
 752          * mode.  The m:: bits take precedence over the g:: bits.
 753          */
 754         va.va_mask = XFS_AT_MODE;
 755         error = xfs_getattr(xfs_vtoi(vp), &va, 0);
 756         if (error)
 757                 return error;
 758
 759         va.va_mask = XFS_AT_MODE;
 760         va.va_mode &= ~(S_IRWXU|S_IRWXG|S_IRWXO);
 761         ap = acl->acl_entry;
 762         for (i = 0; i < acl->acl_cnt; ++i) {
 763                 switch (ap->ae_tag) {
 764                 case ACL_USER_OBJ:
 765                         va.va_mode |= ap->ae_perm << 6;
 766                         break;
 767                 case ACL_GROUP_OBJ:
 768                         gap = ap;
 769                         break;
 770                 case ACL_MASK:  /* more than just standard modes */
 771                         nomask = 0;
 772                         va.va_mode |= ap->ae_perm << 3;
 773                         *basicperms = 0;
 774                         break;
 775                 case ACL_OTHER:
 776                         va.va_mode |= ap->ae_perm;
 777                         break;
 778                 default:        /* more than just standard modes */
 779                         *basicperms = 0;
 780                         break;
 781                 }
 782                 ap++;
 783         }
 784
 785         /* Set the group bits from ACL_GROUP_OBJ if there's no ACL_MASK */
 786         if (gap && nomask)
 787                 va.va_mode |= gap->ae_perm << 3;
 788
 789         return xfs_setattr(xfs_vtoi(vp), &va, 0, sys_cred);
 790 }
 791
 792 /*
 793  * The permissions for the special ACL entries (u::, g::[m::], o::) are
 794  * actually stored in the file mode (if there is both a group and a mask,
 795  * the group is stored in the ACL entry and the mask is stored on the file).
 796  * This allows the mode to remain automatically in sync with the ACL without
 797  * the need for a call-back to the ACL system at every point where the mode
 798  * could change.  This function takes the permissions from the specified mode
 799  * and places it in the supplied ACL.
 800  *
 801  * This implementation draws its validity from the fact that, when the ACL
 802  * was assigned, the mode was copied from the ACL.
 803  * If the mode did not change, therefore, the mode remains exactly what was
 804  * taken from the special ACL entries at assignment.
 805  * If a subsequent chmod() was done, the POSIX spec says that the change in
 806  * mode must cause an update to the ACL seen at user level and used for
 807  * access checks.  Before and after a mode change, therefore, the file mode
 808  * most accurately reflects what the special ACL entries should permit/deny.
 809  *
 810  * CAVEAT: If someone sets the SGI_ACL_FILE attribute directly,
 811  *         the existing mode bits will override whatever is in the
 812  *         ACL. Similarly, if there is a pre-existing ACL that was
 813  *         never in sync with its mode (owing to a bug in 6.5 and
 814  *         before), it will now magically (or mystically) be
 815  *         synchronized.  This could cause slight astonishment, but
 816  *         it is better than inconsistent permissions.
 817  *
 818  * The supplied ACL is a template that may contain any combination
 819  * of special entries.  These are treated as place holders when we fill
 820  * out the ACL.  This routine does not add or remove special entries, it
 821  * simply unites each special entry with its associated set of permissions.
 822  */
 823 STATIC void
 824 xfs_acl_sync_mode(
 825         mode_t          mode,
 826         xfs_acl_t       *acl)
 827 {
 828         int             i, nomask = 1;
 829         xfs_acl_entry_t *ap;
 830         xfs_acl_entry_t *gap = NULL;
 831
 832         /*
 833          * Set ACL entries. POSIX1003.1eD16 requires that the MASK
 834          * be set instead of the GROUP entry, if there is a MASK.
 835          */
 836         for (ap = acl->acl_entry, i = 0; i < acl->acl_cnt; ap++, i++) {
 837                 switch (ap->ae_tag) {
 838                 case ACL_USER_OBJ:
 839                         ap->ae_perm = (mode >> 6) & 0x7;
 840                         break;
 841                 case ACL_GROUP_OBJ:
 842                         gap = ap;
 843                         break;
 844                 case ACL_MASK:
 845                         nomask = 0;
 846                         ap->ae_perm = (mode >> 3) & 0x7;
 847                         break;
 848                 case ACL_OTHER:
 849                         ap->ae_perm = mode & 0x7;
 850                         break;
 851                 default:
 852                         break;
 853                 }
 854         }
 855         /* Set the ACL_GROUP_OBJ if there's no ACL_MASK */
 856         if (gap && nomask)
 857                 gap->ae_perm = (mode >> 3) & 0x7;
 858 }
 859
 860 /*
 861  * When inheriting an Access ACL from a directory Default ACL,
 862  * the ACL bits are set to the intersection of the ACL default
 863  * permission bits and the file permission bits in mode. If there
 864  * are no permission bits on the file then we must not give them
 865  * the ACL. This is what what makes umask() work with ACLs.
 866  */
 867 STATIC void
 868 xfs_acl_filter_mode(
 869         mode_t          mode,
 870         xfs_acl_t       *acl)
 871 {
 872         int             i, nomask = 1;
 873         xfs_acl_entry_t *ap;
 874         xfs_acl_entry_t *gap = NULL;
 875
 876         /*
 877          * Set ACL entries. POSIX1003.1eD16 requires that the MASK
 878          * be merged with GROUP entry, if there is a MASK.
 879          */
 880         for (ap = acl->acl_entry, i = 0; i < acl->acl_cnt; ap++, i++) {
 881                 switch (ap->ae_tag) {
 882                 case ACL_USER_OBJ:
 883                         ap->ae_perm &= (mode >> 6) & 0x7;
 884                         break;
 885                 case ACL_GROUP_OBJ:
 886                         gap = ap;
 887                         break;
 888                 case ACL_MASK:
 889                         nomask = 0;
 890                         ap->ae_perm &= (mode >> 3) & 0x7;
 891                         break;
 892                 case ACL_OTHER:
 893                         ap->ae_perm &= mode & 0x7;
 894                         break;
 895                 default:
 896                         break;
 897                 }
 898         }
 899         /* Set the ACL_GROUP_OBJ if there's no ACL_MASK */
 900         if (gap && nomask)
 901                 gap->ae_perm &= (mode >> 3) & 0x7;
 902 }