fs/xfs/xfs_acl.c

   1 /*
   2  * Copyright (c) 2001-2002 Silicon Graphics, Inc.  All Rights Reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of version 2 of the GNU General Public License as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it would be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  11  *
  12  * Further, this software is distributed without any warranty that it is
  13  * free of the rightful claim of any third person regarding infringement
  14  * or the like.  Any license provided herein, whether implied or
  15  * otherwise, applies only to this software file.  Patent licenses, if
  16  * any, provided herein do not apply to combinations of this program with
  17  * other software, or any other product whatsoever.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write the Free Software Foundation, Inc., 59
  21  * Temple Place - Suite 330, Boston MA 02111-1307, USA.
  22  *
  23  * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
  24  * Mountain View, CA  94043, or:
  25  *
  26  * http://www.sgi.com
  27  *
  28  * For further information regarding this notice, see:
  29  *
  30  * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
  31  */
  32
  33 #include "xfs.h"
  34
  35 #include "xfs_inum.h"
  36 #include "xfs_dir.h"
  37 #include "xfs_dir2.h"
  38 #include "xfs_alloc_btree.h"
  39 #include "xfs_bmap_btree.h"
  40 #include "xfs_ialloc_btree.h"
  41 #include "xfs_btree.h"
  42 #include "xfs_attr_sf.h"
  43 #include "xfs_dir_sf.h"
  44 #include "xfs_dir2_sf.h"
  45 #include "xfs_dinode.h"
  46 #include "xfs_inode.h"
  47 #include "xfs_acl.h"
  48 #include "xfs_mac.h"
  49 #include "xfs_attr.h"
  50
  51 #include <linux/posix_acl_xattr.h>
  52
  53 STATIC int      xfs_acl_setmode(vnode_t *, xfs_acl_t *, int *);
  54 STATIC void     xfs_acl_filter_mode(mode_t, xfs_acl_t *);
  55 STATIC void     xfs_acl_get_endian(xfs_acl_t *);
  56 STATIC int      xfs_acl_access(uid_t, gid_t, xfs_acl_t *, mode_t, cred_t *);
  57 STATIC int      xfs_acl_invalid(xfs_acl_t *);
  58 STATIC void     xfs_acl_sync_mode(mode_t, xfs_acl_t *);
  59 STATIC void     xfs_acl_get_attr(vnode_t *, xfs_acl_t *, int, int, int *);
  60 STATIC void     xfs_acl_set_attr(vnode_t *, xfs_acl_t *, int, int *);
  61 STATIC int      xfs_acl_allow_set(vnode_t *, int);
  62
  63 kmem_zone_t *xfs_acl_zone;
  64
  65
  66 /*
  67  * Test for existence of access ACL attribute as efficiently as possible.
  68  */
  69 int
  70 xfs_acl_vhasacl_access(
  71         vnode_t         *vp)
  72 {
  73         int             error;
  74
  75         xfs_acl_get_attr(vp, NULL, _ACL_TYPE_ACCESS, ATTR_KERNOVAL, &error);
  76         return (error == 0);
  77 }
  78
  79 /*
  80  * Test for existence of default ACL attribute as efficiently as possible.
  81  */
  82 int
  83 xfs_acl_vhasacl_default(
  84         vnode_t         *vp)
  85 {
  86         int             error;
  87
  88         if (vp->v_type != VDIR)
  89                 return 0;
  90         xfs_acl_get_attr(vp, NULL, _ACL_TYPE_DEFAULT, ATTR_KERNOVAL, &error);
  91         return (error == 0);
  92 }
  93
  94 /*
  95  * Convert from extended attribute representation to in-memory for XFS.
  96  */
  97 STATIC int
  98 posix_acl_xattr_to_xfs(
  99         posix_acl_xattr_header  *src,
 100         size_t                  size,
 101         xfs_acl_t               *dest)
 102 {
 103         posix_acl_xattr_entry   *src_entry;
 104         xfs_acl_entry_t         *dest_entry;
 105         int                     n;
 106
 107         if (!src || !dest)
 108                 return EINVAL;
 109
 110         if (size < sizeof(posix_acl_xattr_header))
 111                 return EINVAL;
 112
 113         if (src->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
 114                 return EINVAL;
 115
 116         memset(dest, 0, sizeof(xfs_acl_t));
 117         dest->acl_cnt = posix_acl_xattr_count(size);
 118         if (dest->acl_cnt < 0 || dest->acl_cnt > XFS_ACL_MAX_ENTRIES)
 119                 return EINVAL;
 120
 121         /*
 122          * acl_set_file(3) may request that we set default ACLs with
 123          * zero length -- defend (gracefully) against that here.
 124          */
 125         if (!dest->acl_cnt)
 126                 return 0;
 127
 128         src_entry = (posix_acl_xattr_entry *)((char *)src + sizeof(*src));
 129         dest_entry = &dest->acl_entry[0];
 130
 131         for (n = 0; n < dest->acl_cnt; n++, src_entry++, dest_entry++) {
 132                 dest_entry->ae_perm = le16_to_cpu(src_entry->e_perm);
 133                 if (_ACL_PERM_INVALID(dest_entry->ae_perm))
 134                         return EINVAL;
 135                 dest_entry->ae_tag  = le16_to_cpu(src_entry->e_tag);
 136                 switch(dest_entry->ae_tag) {
 137                 case ACL_USER:
 138                 case ACL_GROUP:
 139                         dest_entry->ae_id = le32_to_cpu(src_entry->e_id);
 140                         break;
 141                 case ACL_USER_OBJ:
 142                 case ACL_GROUP_OBJ:
 143                 case ACL_MASK:
 144                 case ACL_OTHER:
 145                         dest_entry->ae_id = ACL_UNDEFINED_ID;
 146                         break;
 147                 default:
 148                         return EINVAL;
 149                 }
 150         }
 151         if (xfs_acl_invalid(dest))
 152                 return EINVAL;
 153
 154         return 0;
 155 }
 156
 157 /*
 158  * Comparison function called from qsort().
 159  * Primary key is ae_tag, secondary key is ae_id.
 160  */
 161 STATIC int
 162 xfs_acl_entry_compare(
 163         const void      *va,
 164         const void      *vb)
 165 {
 166         xfs_acl_entry_t *a = (xfs_acl_entry_t *)va,
 167                         *b = (xfs_acl_entry_t *)vb;
 168
 169         if (a->ae_tag == b->ae_tag)
 170                 return (a->ae_id - b->ae_id);
 171         return (a->ae_tag - b->ae_tag);
 172 }
 173
 174 /*
 175  * Convert from in-memory XFS to extended attribute representation.
 176  */
 177 STATIC int
 178 posix_acl_xfs_to_xattr(
 179         xfs_acl_t               *src,
 180         posix_acl_xattr_header  *dest,
 181         size_t                  size)
 182 {
 183         int                     n;
 184         size_t                  new_size = posix_acl_xattr_size(src->acl_cnt);
 185         posix_acl_xattr_entry   *dest_entry;
 186         xfs_acl_entry_t         *src_entry;
 187
 188         if (size < new_size)
 189                 return -ERANGE;
 190
 191         /* Need to sort src XFS ACL by <ae_tag,ae_id> */
 192         qsort(src->acl_entry, src->acl_cnt, sizeof(src->acl_entry[0]),
 193                 xfs_acl_entry_compare);
 194
 195         dest->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
 196         dest_entry = &dest->a_entries[0];
 197         src_entry = &src->acl_entry[0];
 198         for (n = 0; n < src->acl_cnt; n++, dest_entry++, src_entry++) {
 199                 dest_entry->e_perm = cpu_to_le16(src_entry->ae_perm);
 200                 if (_ACL_PERM_INVALID(src_entry->ae_perm))
 201                         return -EINVAL;
 202                 dest_entry->e_tag  = cpu_to_le16(src_entry->ae_tag);
 203                 switch (src_entry->ae_tag) {
 204                 case ACL_USER:
 205                 case ACL_GROUP:
 206                         dest_entry->e_id = cpu_to_le32(src_entry->ae_id);
 207                                 break;
 208                 case ACL_USER_OBJ:
 209                 case ACL_GROUP_OBJ:
 210                 case ACL_MASK:
 211                 case ACL_OTHER:
 212                         dest_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
 213                         break;
 214                 default:
 215                         return -EINVAL;
 216                 }
 217         }
 218         return new_size;
 219 }
 220
 221 int
 222 xfs_acl_vget(
 223         vnode_t         *vp,
 224         void            *acl,
 225         size_t          size,
 226         int             kind)
 227 {
 228         int                     error;
 229         xfs_acl_t               *xfs_acl = NULL;
 230         posix_acl_xattr_header  *ext_acl = acl;
 231         int                     flags = 0;
 232
 233         VN_HOLD(vp);
 234         if ((error = _MAC_VACCESS(vp, NULL, VREAD)))
 235                 goto out;
 236         if(size) {
 237                 if (!(_ACL_ALLOC(xfs_acl))) {
 238                         error = ENOMEM;
 239                         goto out;
 240                 }
 241                 memset(xfs_acl, 0, sizeof(xfs_acl_t));
 242         } else
 243                 flags = ATTR_KERNOVAL;
 244
 245         xfs_acl_get_attr(vp, xfs_acl, kind, flags, &error);
 246         if (error)
 247                 goto out;
 248
 249         if (!size) {
 250                 error = -posix_acl_xattr_size(XFS_ACL_MAX_ENTRIES);
 251         } else {
 252                 if (xfs_acl_invalid(xfs_acl)) {
 253                         error = EINVAL;
 254                         goto out;
 255                 }
 256                 if (kind == _ACL_TYPE_ACCESS) {
 257                         vattr_t va;
 258
 259                         va.va_mask = XFS_AT_MODE;
 260                         VOP_GETATTR(vp, &va, 0, sys_cred, error);
 261                         if (error)
 262                                 goto out;
 263                         xfs_acl_sync_mode(va.va_mode, xfs_acl);
 264                 }
 265                 error = -posix_acl_xfs_to_xattr(xfs_acl, ext_acl, size);
 266         }
 267 out:
 268         VN_RELE(vp);
 269         if(xfs_acl)
 270                 _ACL_FREE(xfs_acl);
 271         return -error;
 272 }
 273
 274 int
 275 xfs_acl_vremove(
 276         vnode_t         *vp,
 277         int             kind)
 278 {
 279         int             error;
 280
 281         VN_HOLD(vp);
 282         error = xfs_acl_allow_set(vp, kind);
 283         if (!error) {
 284                 VOP_ATTR_REMOVE(vp, kind == _ACL_TYPE_DEFAULT?
 285                                 SGI_ACL_DEFAULT: SGI_ACL_FILE,
 286                                 ATTR_ROOT, sys_cred, error);
 287                 if (error == ENOATTR)
 288                         error = 0;      /* 'scool */
 289         }
 290         VN_RELE(vp);
 291         return -error;
 292 }
 293
 294 int
 295 xfs_acl_vset(
 296         vnode_t                 *vp,
 297         void                    *acl,
 298         size_t                  size,
 299         int                     kind)
 300 {
 301         posix_acl_xattr_header  *ext_acl = acl;
 302         xfs_acl_t               *xfs_acl;
 303         int                     error;
 304         int                     basicperms = 0; /* more than std unix perms? */
 305
 306         if (!acl)
 307                 return -EINVAL;
 308
 309         if (!(_ACL_ALLOC(xfs_acl)))
 310                 return -ENOMEM;
 311
 312         error = posix_acl_xattr_to_xfs(ext_acl, size, xfs_acl);
 313         if (error) {
 314                 _ACL_FREE(xfs_acl);
 315                 return -error;
 316         }
 317         if (!xfs_acl->acl_cnt) {
 318                 _ACL_FREE(xfs_acl);
 319                 return 0;
 320         }
 321
 322         VN_HOLD(vp);
 323         error = xfs_acl_allow_set(vp, kind);
 324         if (error)
 325                 goto out;
 326
 327         /* Incoming ACL exists, set file mode based on its value */
 328         if (kind == _ACL_TYPE_ACCESS)
 329                 xfs_acl_setmode(vp, xfs_acl, &basicperms);
 330
 331         /*
 332          * If we have more than std unix permissions, set up the actual attr.
 333          * Otherwise, delete any existing attr.  This prevents us from
 334          * having actual attrs for permissions that can be stored in the
 335          * standard permission bits.
 336          */
 337         if (!basicperms) {
 338                 xfs_acl_set_attr(vp, xfs_acl, kind, &error);
 339         } else {
 340                 xfs_acl_vremove(vp, _ACL_TYPE_ACCESS);
 341         }
 342
 343
 344 out:
 345         VN_RELE(vp);
 346         _ACL_FREE(xfs_acl);
 347         return -error;
 348 }
 349
 350 int
 351 xfs_acl_iaccess(
 352         xfs_inode_t     *ip,
 353         mode_t          mode,
 354         cred_t          *cr)
 355 {
 356         xfs_acl_t       *acl;
 357         int             error;
 358
 359         if (!(_ACL_ALLOC(acl)))
 360                 return -1;
 361
 362         /* If the file has no ACL return -1. */
 363         if (xfs_attr_fetch(ip, SGI_ACL_FILE, (char *)acl, sizeof(xfs_acl_t))) {
 364                 _ACL_FREE(acl);
 365                 return -1;
 366         }
 367         xfs_acl_get_endian(acl);
 368
 369         /* If the file has an empty ACL return -1. */
 370         if (acl->acl_cnt == XFS_ACL_NOT_PRESENT) {
 371                 _ACL_FREE(acl);
 372                 return -1;
 373         }
 374
 375         /* Synchronize ACL with mode bits */
 376         xfs_acl_sync_mode(ip->i_d.di_mode, acl);
 377
 378         error = xfs_acl_access(ip->i_d.di_uid, ip->i_d.di_gid, acl, mode, cr);
 379         _ACL_FREE(acl);
 380         return error;
 381 }
 382
 383 STATIC int
 384 xfs_acl_allow_set(
 385         vnode_t         *vp,
 386         int             kind)
 387 {
 388         vattr_t         va;
 389         int             error;
 390
 391         if (kind == _ACL_TYPE_DEFAULT && vp->v_type != VDIR)
 392                 return ENOTDIR;
 393         if (vp->v_vfsp->vfs_flag & VFS_RDONLY)
 394                 return EROFS;
 395         if ((error = _MAC_VACCESS(vp, NULL, VWRITE)))
 396                 return error;
 397         va.va_mask = XFS_AT_UID;
 398         VOP_GETATTR(vp, &va, 0, NULL, error);
 399         if (error)
 400                 return error;
 401         if (va.va_uid != current->fsuid && !capable(CAP_FOWNER))
 402                 return EPERM;
 403         return error;
 404 }
 405
 406 /*
 407  * Look for any effective exec access, to allow CAP_DAC_OVERRIDE for exec.
 408  * Ignore checking for exec in USER_OBJ when there is no mask, because
 409  * in this "minimal acl" case we don't have any actual acls, and we
 410  * won't even be here.
 411  */
 412 STATIC int
 413 xfs_acl_find_any_exec(
 414         xfs_acl_t       *fap)
 415 {
 416         int             i;
 417         int             masked_aces = 0;
 418         int             mask = 0;
 419
 420         for (i = 0; i < fap->acl_cnt; i++) {
 421                 if (fap->acl_entry[i].ae_perm & ACL_EXECUTE) {
 422                         if (fap->acl_entry[i].ae_tag & (ACL_USER_OBJ|ACL_OTHER))
 423                                 return 1;
 424
 425                         if (fap->acl_entry[i].ae_tag == ACL_MASK)
 426                                 mask = fap->acl_entry[i].ae_perm;
 427                         else
 428                                 masked_aces |= fap->acl_entry[i].ae_perm;
 429
 430                         if ((mask & masked_aces) & ACL_EXECUTE)
 431                                 return 1;
 432                 }
 433         }
 434
 435         return 0;
 436 }
 437
 438 /*
 439  * The access control process to determine the access permission:
 440  *      if uid == file owner id, use the file owner bits.
 441  *      if gid == file owner group id, use the file group bits.
 442  *      scan ACL for a maching user or group, and use matched entry
 443  *      permission. Use total permissions of all matching group entries,
 444  *      until all acl entries are exhausted. The final permission produced
 445  *      by matching acl entry or entries needs to be & with group permission.
 446  *      if not owner, owning group, or matching entry in ACL, use file
 447  *      other bits.  Don't allow CAP_DAC_OVERRIDE on exec access unless
 448  *      there is some effective exec access somewhere.
 449  */
 450 STATIC int
 451 xfs_acl_capability_check(
 452         mode_t          mode,
 453         cred_t          *cr,
 454         xfs_acl_t       *fap)
 455 {
 456         if ((mode & ACL_READ) && !capable_cred(cr, CAP_DAC_READ_SEARCH))
 457                 return EACCES;
 458         if ((mode & ACL_WRITE) && !capable_cred(cr, CAP_DAC_OVERRIDE))
 459                 return EACCES;
 460         if ((mode & ACL_EXECUTE) &&
 461             (!capable_cred(cr, CAP_DAC_OVERRIDE) ||
 462              !xfs_acl_find_any_exec(fap))) {
 463                 return EACCES;
 464         }
 465
 466         return 0;
 467 }
 468
 469 /*
 470  * Note: cr is only used here for the capability check if the ACL test fails.
 471  *       It is not used to find out the credentials uid or groups etc, as was
 472  *       done in IRIX. It is assumed that the uid and groups for the current
 473  *       thread are taken from "current" instead of the cr parameter.
 474  */
 475 STATIC int
 476 xfs_acl_access(
 477         uid_t           fuid,
 478         gid_t           fgid,
 479         xfs_acl_t       *fap,
 480         mode_t          md,
 481         cred_t          *cr)
 482 {
 483         xfs_acl_entry_t matched;
 484         int             i, allows;
 485         int             maskallows = -1;        /* true, but not 1, either */
 486         int             seen_userobj = 0;
 487
 488         matched.ae_tag = 0;     /* Invalid type */
 489         md >>= 6;       /* Normalize the bits for comparison */
 490
 491         for (i = 0; i < fap->acl_cnt; i++) {
 492                 /*
 493                  * Break out if we've got a user_obj entry or
 494                  * a user entry and the mask (and have processed USER_OBJ)
 495                  */
 496                 if (matched.ae_tag == ACL_USER_OBJ)
 497                         break;
 498                 if (matched.ae_tag == ACL_USER) {
 499                         if (maskallows != -1 && seen_userobj)
 500                                 break;
 501                         if (fap->acl_entry[i].ae_tag != ACL_MASK &&
 502                             fap->acl_entry[i].ae_tag != ACL_USER_OBJ)
 503                                 continue;
 504                 }
 505                 /* True if this entry allows the requested access */
 506                 allows = ((fap->acl_entry[i].ae_perm & md) == md);
 507
 508                 switch (fap->acl_entry[i].ae_tag) {
 509                 case ACL_USER_OBJ:
 510                         seen_userobj = 1;
 511                         if (fuid != current->fsuid)
 512                                 continue;
 513                         matched.ae_tag = ACL_USER_OBJ;
 514                         matched.ae_perm = allows;
 515                         break;
 516                 case ACL_USER:
 517                         if (fap->acl_entry[i].ae_id != current->fsuid)
 518                                 continue;
 519                         matched.ae_tag = ACL_USER;
 520                         matched.ae_perm = allows;
 521                         break;
 522                 case ACL_GROUP_OBJ:
 523                         if ((matched.ae_tag == ACL_GROUP_OBJ ||
 524                             matched.ae_tag == ACL_GROUP) && !allows)
 525                                 continue;
 526                         if (!in_group_p(fgid))
 527                                 continue;
 528                         matched.ae_tag = ACL_GROUP_OBJ;
 529                         matched.ae_perm = allows;
 530                         break;
 531                 case ACL_GROUP:
 532                         if ((matched.ae_tag == ACL_GROUP_OBJ ||
 533                             matched.ae_tag == ACL_GROUP) && !allows)
 534                                 continue;
 535                         if (!in_group_p(fap->acl_entry[i].ae_id))
 536                                 continue;
 537                         matched.ae_tag = ACL_GROUP;
 538                         matched.ae_perm = allows;
 539                         break;
 540                 case ACL_MASK:
 541                         maskallows = allows;
 542                         break;
 543                 case ACL_OTHER:
 544                         if (matched.ae_tag != 0)
 545                                 continue;
 546                         matched.ae_tag = ACL_OTHER;
 547                         matched.ae_perm = allows;
 548                         break;
 549                 }
 550         }
 551         /*
 552          * First possibility is that no matched entry allows access.
 553          * The capability to override DAC may exist, so check for it.
 554          */
 555         switch (matched.ae_tag) {
 556         case ACL_OTHER:
 557         case ACL_USER_OBJ:
 558                 if (matched.ae_perm)
 559                         return 0;
 560                 break;
 561         case ACL_USER:
 562         case ACL_GROUP_OBJ:
 563         case ACL_GROUP:
 564                 if (maskallows && matched.ae_perm)
 565                         return 0;
 566                 break;
 567         case 0:
 568                 break;
 569         }
 570
 571         return xfs_acl_capability_check(md, cr, fap);
 572 }
 573
 574 /*
 575  * ACL validity checker.
 576  *   This acl validation routine checks each ACL entry read in makes sense.
 577  */
 578 STATIC int
 579 xfs_acl_invalid(
 580         xfs_acl_t       *aclp)
 581 {
 582         xfs_acl_entry_t *entry, *e;
 583         int             user = 0, group = 0, other = 0, mask = 0;
 584         int             mask_required = 0;
 585         int             i, j;
 586
 587         if (!aclp)
 588                 goto acl_invalid;
 589
 590         if (aclp->acl_cnt > XFS_ACL_MAX_ENTRIES)
 591                 goto acl_invalid;
 592
 593         for (i = 0; i < aclp->acl_cnt; i++) {
 594                 entry = &aclp->acl_entry[i];
 595                 switch (entry->ae_tag) {
 596                 case ACL_USER_OBJ:
 597                         if (user++)
 598                                 goto acl_invalid;
 599                         break;
 600                 case ACL_GROUP_OBJ:
 601                         if (group++)
 602                                 goto acl_invalid;
 603                         break;
 604                 case ACL_OTHER:
 605                         if (other++)
 606                                 goto acl_invalid;
 607                         break;
 608                 case ACL_USER:
 609                 case ACL_GROUP:
 610                         for (j = i + 1; j < aclp->acl_cnt; j++) {
 611                                 e = &aclp->acl_entry[j];
 612                                 if (e->ae_id == entry->ae_id &&
 613                                     e->ae_tag == entry->ae_tag)
 614                                         goto acl_invalid;
 615                         }
 616                         mask_required++;
 617                         break;
 618                 case ACL_MASK:
 619                         if (mask++)
 620                                 goto acl_invalid;
 621                         break;
 622                 default:
 623                         goto acl_invalid;
 624                 }
 625         }
 626         if (!user || !group || !other || (mask_required && !mask))
 627                 goto acl_invalid;
 628         else
 629                 return 0;
 630 acl_invalid:
 631         return EINVAL;
 632 }
 633
 634 /*
 635  * Do ACL endian conversion.
 636  */
 637 STATIC void
 638 xfs_acl_get_endian(
 639         xfs_acl_t       *aclp)
 640 {
 641         xfs_acl_entry_t *ace, *end;
 642
 643         INT_SET(aclp->acl_cnt, ARCH_CONVERT, aclp->acl_cnt);
 644         end = &aclp->acl_entry[0]+aclp->acl_cnt;
 645         for (ace = &aclp->acl_entry[0]; ace < end; ace++) {
 646                 INT_SET(ace->ae_tag, ARCH_CONVERT, ace->ae_tag);
 647                 INT_SET(ace->ae_id, ARCH_CONVERT, ace->ae_id);
 648                 INT_SET(ace->ae_perm, ARCH_CONVERT, ace->ae_perm);
 649         }
 650 }
 651
 652 /*
 653  * Get the ACL from the EA and do endian conversion.
 654  */
 655 STATIC void
 656 xfs_acl_get_attr(
 657         vnode_t         *vp,
 658         xfs_acl_t       *aclp,
 659         int             kind,
 660         int             flags,
 661         int             *error)
 662 {
 663         int             len = sizeof(xfs_acl_t);
 664
 665         ASSERT((flags & ATTR_KERNOVAL) ? (aclp == NULL) : 1);
 666         flags |= ATTR_ROOT;
 667         VOP_ATTR_GET(vp,
 668                 kind == _ACL_TYPE_ACCESS ? SGI_ACL_FILE : SGI_ACL_DEFAULT,
 669                 (char *)aclp, &len, flags, sys_cred, *error);
 670         if (*error || (flags & ATTR_KERNOVAL))
 671                 return;
 672         xfs_acl_get_endian(aclp);
 673 }
 674
 675 /*
 676  * Set the EA with the ACL and do endian conversion.
 677  */
 678 STATIC void
 679 xfs_acl_set_attr(
 680         vnode_t         *vp,
 681         xfs_acl_t       *aclp,
 682         int             kind,
 683         int             *error)
 684 {
 685         xfs_acl_entry_t *ace, *newace, *end;
 686         xfs_acl_t       *newacl;
 687         int             len;
 688
 689         if (!(_ACL_ALLOC(newacl))) {
 690                 *error = ENOMEM;
 691                 return;
 692         }
 693
 694         len = sizeof(xfs_acl_t) -
 695               (sizeof(xfs_acl_entry_t) * (XFS_ACL_MAX_ENTRIES - aclp->acl_cnt));
 696         end = &aclp->acl_entry[0]+aclp->acl_cnt;
 697         for (ace = &aclp->acl_entry[0], newace = &newacl->acl_entry[0];
 698              ace < end;
 699              ace++, newace++) {
 700                 INT_SET(newace->ae_tag, ARCH_CONVERT, ace->ae_tag);
 701                 INT_SET(newace->ae_id, ARCH_CONVERT, ace->ae_id);
 702                 INT_SET(newace->ae_perm, ARCH_CONVERT, ace->ae_perm);
 703         }
 704         INT_SET(newacl->acl_cnt, ARCH_CONVERT, aclp->acl_cnt);
 705         VOP_ATTR_SET(vp,
 706                 kind == _ACL_TYPE_ACCESS ? SGI_ACL_FILE: SGI_ACL_DEFAULT,
 707                 (char *)newacl, len, ATTR_ROOT, sys_cred, *error);
 708         _ACL_FREE(newacl);
 709 }
 710
 711 int
 712 xfs_acl_vtoacl(
 713         vnode_t         *vp,
 714         xfs_acl_t       *access_acl,
 715         xfs_acl_t       *default_acl)
 716 {
 717         vattr_t         va;
 718         int             error = 0;
 719
 720         if (access_acl) {
 721                 /*
 722                  * Get the Access ACL and the mode.  If either cannot
 723                  * be obtained for some reason, invalidate the access ACL.
 724                  */
 725                 xfs_acl_get_attr(vp, access_acl, _ACL_TYPE_ACCESS, 0, &error);
 726                 if (!error) {
 727                         /* Got the ACL, need the mode... */
 728                         va.va_mask = XFS_AT_MODE;
 729                         VOP_GETATTR(vp, &va, 0, sys_cred, error);
 730                 }
 731
 732                 if (error)
 733                         access_acl->acl_cnt = XFS_ACL_NOT_PRESENT;
 734                 else /* We have a good ACL and the file mode, synchronize. */
 735                         xfs_acl_sync_mode(va.va_mode, access_acl);
 736         }
 737
 738         if (default_acl) {
 739                 xfs_acl_get_attr(vp, default_acl, _ACL_TYPE_DEFAULT, 0, &error);
 740                 if (error)
 741                         default_acl->acl_cnt = XFS_ACL_NOT_PRESENT;
 742         }
 743         return error;
 744 }
 745
 746 /*
 747  * This function retrieves the parent directory's acl, processes it
 748  * and lets the child inherit the acl(s) that it should.
 749  */
 750 int
 751 xfs_acl_inherit(
 752         vnode_t         *vp,
 753         vattr_t         *vap,
 754         xfs_acl_t       *pdaclp)
 755 {
 756         xfs_acl_t       *cacl;
 757         int             error = 0;
 758         int             basicperms = 0;
 759
 760         /*
 761          * If the parent does not have a default ACL, or it's an
 762          * invalid ACL, we're done.
 763          */
 764         if (!vp)
 765                 return 0;
 766         if (!pdaclp || xfs_acl_invalid(pdaclp))
 767                 return 0;
 768
 769         /*
 770          * Copy the default ACL of the containing directory to
 771          * the access ACL of the new file and use the mode that
 772          * was passed in to set up the correct initial values for
 773          * the u::,g::[m::], and o:: entries.  This is what makes
 774          * umask() "work" with ACL's.
 775          */
 776
 777         if (!(_ACL_ALLOC(cacl)))
 778                 return ENOMEM;
 779
 780         memcpy(cacl, pdaclp, sizeof(xfs_acl_t));
 781         xfs_acl_filter_mode(vap->va_mode, cacl);
 782         xfs_acl_setmode(vp, cacl, &basicperms);
 783
 784         /*
 785          * Set the Default and Access ACL on the file.  The mode is already
 786          * set on the file, so we don't need to worry about that.
 787          *
 788          * If the new file is a directory, its default ACL is a copy of
 789          * the containing directory's default ACL.
 790          */
 791         if (vp->v_type == VDIR)
 792                 xfs_acl_set_attr(vp, pdaclp, _ACL_TYPE_DEFAULT, &error);
 793         if (!error && !basicperms)
 794                 xfs_acl_set_attr(vp, cacl, _ACL_TYPE_ACCESS, &error);
 795         _ACL_FREE(cacl);
 796         return error;
 797 }
 798
 799 /*
 800  * Set up the correct mode on the file based on the supplied ACL.  This
 801  * makes sure that the mode on the file reflects the state of the
 802  * u::,g::[m::], and o:: entries in the ACL.  Since the mode is where
 803  * the ACL is going to get the permissions for these entries, we must
 804  * synchronize the mode whenever we set the ACL on a file.
 805  */
 806 STATIC int
 807 xfs_acl_setmode(
 808         vnode_t         *vp,
 809         xfs_acl_t       *acl,
 810         int             *basicperms)
 811 {
 812         vattr_t         va;
 813         xfs_acl_entry_t *ap;
 814         xfs_acl_entry_t *gap = NULL;
 815         int             i, error, nomask = 1;
 816
 817         *basicperms = 1;
 818
 819         if (acl->acl_cnt == XFS_ACL_NOT_PRESENT)
 820                 return 0;
 821
 822         /*
 823          * Copy the u::, g::, o::, and m:: bits from the ACL into the
 824          * mode.  The m:: bits take precedence over the g:: bits.
 825          */
 826         va.va_mask = XFS_AT_MODE;
 827         VOP_GETATTR(vp, &va, 0, sys_cred, error);
 828         if (error)
 829                 return error;
 830
 831         va.va_mask = XFS_AT_MODE;
 832         va.va_mode &= ~(S_IRWXU|S_IRWXG|S_IRWXO);
 833         ap = acl->acl_entry;
 834         for (i = 0; i < acl->acl_cnt; ++i) {
 835                 switch (ap->ae_tag) {
 836                 case ACL_USER_OBJ:
 837                         va.va_mode |= ap->ae_perm << 6;
 838                         break;
 839                 case ACL_GROUP_OBJ:
 840                         gap = ap;
 841                         break;
 842                 case ACL_MASK:  /* more than just standard modes */
 843                         nomask = 0;
 844                         va.va_mode |= ap->ae_perm << 3;
 845                         *basicperms = 0;
 846                         break;
 847                 case ACL_OTHER:
 848                         va.va_mode |= ap->ae_perm;
 849                         break;
 850                 default:        /* more than just standard modes */
 851                         *basicperms = 0;
 852                         break;
 853                 }
 854                 ap++;
 855         }
 856
 857         /* Set the group bits from ACL_GROUP_OBJ if there's no ACL_MASK */
 858         if (gap && nomask)
 859                 va.va_mode |= gap->ae_perm << 3;
 860
 861         VOP_SETATTR(vp, &va, 0, sys_cred, error);
 862         return error;
 863 }
 864
 865 /*
 866  * The permissions for the special ACL entries (u::, g::[m::], o::) are
 867  * actually stored in the file mode (if there is both a group and a mask,
 868  * the group is stored in the ACL entry and the mask is stored on the file).
 869  * This allows the mode to remain automatically in sync with the ACL without
 870  * the need for a call-back to the ACL system at every point where the mode
 871  * could change.  This function takes the permissions from the specified mode
 872  * and places it in the supplied ACL.
 873  *
 874  * This implementation draws its validity from the fact that, when the ACL
 875  * was assigned, the mode was copied from the ACL.
 876  * If the mode did not change, therefore, the mode remains exactly what was
 877  * taken from the special ACL entries at assignment.
 878  * If a subsequent chmod() was done, the POSIX spec says that the change in
 879  * mode must cause an update to the ACL seen at user level and used for
 880  * access checks.  Before and after a mode change, therefore, the file mode
 881  * most accurately reflects what the special ACL entries should permit/deny.
 882  *
 883  * CAVEAT: If someone sets the SGI_ACL_FILE attribute directly,
 884  *         the existing mode bits will override whatever is in the
 885  *         ACL. Similarly, if there is a pre-existing ACL that was
 886  *         never in sync with its mode (owing to a bug in 6.5 and
 887  *         before), it will now magically (or mystically) be
 888  *         synchronized.  This could cause slight astonishment, but
 889  *         it is better than inconsistent permissions.
 890  *
 891  * The supplied ACL is a template that may contain any combination
 892  * of special entries.  These are treated as place holders when we fill
 893  * out the ACL.  This routine does not add or remove special entries, it
 894  * simply unites each special entry with its associated set of permissions.
 895  */
 896 STATIC void
 897 xfs_acl_sync_mode(
 898         mode_t          mode,
 899         xfs_acl_t       *acl)
 900 {
 901         int             i, nomask = 1;
 902         xfs_acl_entry_t *ap;
 903         xfs_acl_entry_t *gap = NULL;
 904
 905         /*
 906          * Set ACL entries. POSIX1003.1eD16 requires that the MASK
 907          * be set instead of the GROUP entry, if there is a MASK.
 908          */
 909         for (ap = acl->acl_entry, i = 0; i < acl->acl_cnt; ap++, i++) {
 910                 switch (ap->ae_tag) {
 911                 case ACL_USER_OBJ:
 912                         ap->ae_perm = (mode >> 6) & 0x7;
 913                         break;
 914                 case ACL_GROUP_OBJ:
 915                         gap = ap;
 916                         break;
 917                 case ACL_MASK:
 918                         nomask = 0;
 919                         ap->ae_perm = (mode >> 3) & 0x7;
 920                         break;
 921                 case ACL_OTHER:
 922                         ap->ae_perm = mode & 0x7;
 923                         break;
 924                 default:
 925                         break;
 926                 }
 927         }
 928         /* Set the ACL_GROUP_OBJ if there's no ACL_MASK */
 929         if (gap && nomask)
 930                 gap->ae_perm = (mode >> 3) & 0x7;
 931 }
 932
 933 /*
 934  * When inheriting an Access ACL from a directory Default ACL,
 935  * the ACL bits are set to the intersection of the ACL default
 936  * permission bits and the file permission bits in mode. If there
 937  * are no permission bits on the file then we must not give them
 938  * the ACL. This is what what makes umask() work with ACLs.
 939  */
 940 STATIC void
 941 xfs_acl_filter_mode(
 942         mode_t          mode,
 943         xfs_acl_t       *acl)
 944 {
 945         int             i, nomask = 1;
 946         xfs_acl_entry_t *ap;
 947         xfs_acl_entry_t *gap = NULL;
 948
 949         /*
 950          * Set ACL entries. POSIX1003.1eD16 requires that the MASK
 951          * be merged with GROUP entry, if there is a MASK.
 952          */
 953         for (ap = acl->acl_entry, i = 0; i < acl->acl_cnt; ap++, i++) {
 954                 switch (ap->ae_tag) {
 955                 case ACL_USER_OBJ:
 956                         ap->ae_perm &= (mode >> 6) & 0x7;
 957                         break;
 958                 case ACL_GROUP_OBJ:
 959                         gap = ap;
 960                         break;
 961                 case ACL_MASK:
 962                         nomask = 0;
 963                         ap->ae_perm &= (mode >> 3) & 0x7;
 964                         break;
 965                 case ACL_OTHER:
 966                         ap->ae_perm &= mode & 0x7;
 967                         break;
 968                 default:
 969                         break;
 970                 }
 971         }
 972         /* Set the ACL_GROUP_OBJ if there's no ACL_MASK */
 973         if (gap && nomask)
 974                 gap->ae_perm &= (mode >> 3) & 0x7;
 975 }