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 EOPNOTSUPP;
 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(size) {
 235                 if (!(_ACL_ALLOC(xfs_acl))) {
 236                         error = ENOMEM;
 237                         goto out;
 238                 }
 239                 memset(xfs_acl, 0, sizeof(xfs_acl_t));
 240         } else
 241                 flags = ATTR_KERNOVAL;
 242
 243         xfs_acl_get_attr(vp, xfs_acl, kind, flags, &error);
 244         if (error)
 245                 goto out;
 246
 247         if (!size) {
 248                 error = -posix_acl_xattr_size(XFS_ACL_MAX_ENTRIES);
 249         } else {
 250                 if (xfs_acl_invalid(xfs_acl)) {
 251                         error = EINVAL;
 252                         goto out;
 253                 }
 254                 if (kind == _ACL_TYPE_ACCESS) {
 255                         vattr_t va;
 256
 257                         va.va_mask = XFS_AT_MODE;
 258                         VOP_GETATTR(vp, &va, 0, sys_cred, error);
 259                         if (error)
 260                                 goto out;
 261                         xfs_acl_sync_mode(va.va_mode, xfs_acl);
 262                 }
 263                 error = -posix_acl_xfs_to_xattr(xfs_acl, ext_acl, size);
 264         }
 265 out:
 266         VN_RELE(vp);
 267         if(xfs_acl)
 268                 _ACL_FREE(xfs_acl);
 269         return -error;
 270 }
 271
 272 int
 273 xfs_acl_vremove(
 274         vnode_t         *vp,
 275         int             kind)
 276 {
 277         int             error;
 278
 279         VN_HOLD(vp);
 280         error = xfs_acl_allow_set(vp, kind);
 281         if (!error) {
 282                 VOP_ATTR_REMOVE(vp, kind == _ACL_TYPE_DEFAULT?
 283                                 SGI_ACL_DEFAULT: SGI_ACL_FILE,
 284                                 ATTR_ROOT, sys_cred, error);
 285                 if (error == ENOATTR)
 286                         error = 0;      /* 'scool */
 287         }
 288         VN_RELE(vp);
 289         return -error;
 290 }
 291
 292 int
 293 xfs_acl_vset(
 294         vnode_t                 *vp,
 295         void                    *acl,
 296         size_t                  size,
 297         int                     kind)
 298 {
 299         posix_acl_xattr_header  *ext_acl = acl;
 300         xfs_acl_t               *xfs_acl;
 301         int                     error;
 302         int                     basicperms = 0; /* more than std unix perms? */
 303
 304         if (!acl)
 305                 return -EINVAL;
 306
 307         if (!(_ACL_ALLOC(xfs_acl)))
 308                 return -ENOMEM;
 309
 310         error = posix_acl_xattr_to_xfs(ext_acl, size, xfs_acl);
 311         if (error) {
 312                 _ACL_FREE(xfs_acl);
 313                 return -error;
 314         }
 315         if (!xfs_acl->acl_cnt) {
 316                 _ACL_FREE(xfs_acl);
 317                 return 0;
 318         }
 319
 320         VN_HOLD(vp);
 321         error = xfs_acl_allow_set(vp, kind);
 322         if (error)
 323                 goto out;
 324
 325         /* Incoming ACL exists, set file mode based on its value */
 326         if (kind == _ACL_TYPE_ACCESS)
 327                 xfs_acl_setmode(vp, xfs_acl, &basicperms);
 328
 329         /*
 330          * If we have more than std unix permissions, set up the actual attr.
 331          * Otherwise, delete any existing attr.  This prevents us from
 332          * having actual attrs for permissions that can be stored in the
 333          * standard permission bits.
 334          */
 335         if (!basicperms) {
 336                 xfs_acl_set_attr(vp, xfs_acl, kind, &error);
 337         } else {
 338                 xfs_acl_vremove(vp, _ACL_TYPE_ACCESS);
 339         }
 340
 341 out:
 342         VN_RELE(vp);
 343         _ACL_FREE(xfs_acl);
 344         return -error;
 345 }
 346
 347 int
 348 xfs_acl_iaccess(
 349         xfs_inode_t     *ip,
 350         mode_t          mode,
 351         cred_t          *cr)
 352 {
 353         xfs_acl_t       *acl;
 354         int             rval;
 355
 356         if (!(_ACL_ALLOC(acl)))
 357                 return -1;
 358
 359         /* If the file has no ACL return -1. */
 360         rval = sizeof(xfs_acl_t);
 361         if (xfs_attr_fetch(ip, SGI_ACL_FILE, SGI_ACL_FILE_SIZE,
 362                         (char *)acl, &rval, ATTR_ROOT | ATTR_KERNACCESS, cr)) {
 363                 _ACL_FREE(acl);
 364                 return -1;
 365         }
 366         xfs_acl_get_endian(acl);
 367
 368         /* If the file has an empty ACL return -1. */
 369         if (acl->acl_cnt == XFS_ACL_NOT_PRESENT) {
 370                 _ACL_FREE(acl);
 371                 return -1;
 372         }
 373
 374         /* Synchronize ACL with mode bits */
 375         xfs_acl_sync_mode(ip->i_d.di_mode, acl);
 376
 377         rval = xfs_acl_access(ip->i_d.di_uid, ip->i_d.di_gid, acl, mode, cr);
 378         _ACL_FREE(acl);
 379         return rval;
 380 }
 381
 382 STATIC int
 383 xfs_acl_allow_set(
 384         vnode_t         *vp,
 385         int             kind)
 386 {
 387         vattr_t         va;
 388         int             error;
 389
 390         if (vp->v_inode.i_flags & (S_IMMUTABLE|S_APPEND))
 391                 return EPERM;
 392         if (kind == _ACL_TYPE_DEFAULT && vp->v_type != VDIR)
 393                 return ENOTDIR;
 394         if (vp->v_vfsp->vfs_flag & VFS_RDONLY)
 395                 return EROFS;
 396         va.va_mask = XFS_AT_UID;
 397         VOP_GETATTR(vp, &va, 0, NULL, error);
 398         if (error)
 399                 return error;
 400         if (va.va_uid != current->fsuid && !capable(CAP_FOWNER))
 401                 return EPERM;
 402         return error;
 403 }
 404
 405 /*
 406  * The access control process to determine the access permission:
 407  *      if uid == file owner id, use the file owner bits.
 408  *      if gid == file owner group id, use the file group bits.
 409  *      scan ACL for a maching user or group, and use matched entry
 410  *      permission. Use total permissions of all matching group entries,
 411  *      until all acl entries are exhausted. The final permission produced
 412  *      by matching acl entry or entries needs to be & with group permission.
 413  *      if not owner, owning group, or matching entry in ACL, use file
 414  *      other bits.
 415  */
 416 STATIC int
 417 xfs_acl_capability_check(
 418         mode_t          mode,
 419         cred_t          *cr)
 420 {
 421         if ((mode & ACL_READ) && !capable_cred(cr, CAP_DAC_READ_SEARCH))
 422                 return EACCES;
 423         if ((mode & ACL_WRITE) && !capable_cred(cr, CAP_DAC_OVERRIDE))
 424                 return EACCES;
 425         if ((mode & ACL_EXECUTE) && !capable_cred(cr, CAP_DAC_OVERRIDE))
 426                 return EACCES;
 427
 428         return 0;
 429 }
 430
 431 /*
 432  * Note: cr is only used here for the capability check if the ACL test fails.
 433  *       It is not used to find out the credentials uid or groups etc, as was
 434  *       done in IRIX. It is assumed that the uid and groups for the current
 435  *       thread are taken from "current" instead of the cr parameter.
 436  */
 437 STATIC int
 438 xfs_acl_access(
 439         uid_t           fuid,
 440         gid_t           fgid,
 441         xfs_acl_t       *fap,
 442         mode_t          md,
 443         cred_t          *cr)
 444 {
 445         xfs_acl_entry_t matched;
 446         int             i, allows;
 447         int             maskallows = -1;        /* true, but not 1, either */
 448         int             seen_userobj = 0;
 449
 450         matched.ae_tag = 0;     /* Invalid type */
 451         md >>= 6;       /* Normalize the bits for comparison */
 452
 453         for (i = 0; i < fap->acl_cnt; i++) {
 454                 /*
 455                  * Break out if we've got a user_obj entry or
 456                  * a user entry and the mask (and have processed USER_OBJ)
 457                  */
 458                 if (matched.ae_tag == ACL_USER_OBJ)
 459                         break;
 460                 if (matched.ae_tag == ACL_USER) {
 461                         if (maskallows != -1 && seen_userobj)
 462                                 break;
 463                         if (fap->acl_entry[i].ae_tag != ACL_MASK &&
 464                             fap->acl_entry[i].ae_tag != ACL_USER_OBJ)
 465                                 continue;
 466                 }
 467                 /* True if this entry allows the requested access */
 468                 allows = ((fap->acl_entry[i].ae_perm & md) == md);
 469
 470                 switch (fap->acl_entry[i].ae_tag) {
 471                 case ACL_USER_OBJ:
 472                         seen_userobj = 1;
 473                         if (fuid != current->fsuid)
 474                                 continue;
 475                         matched.ae_tag = ACL_USER_OBJ;
 476                         matched.ae_perm = allows;
 477                         break;
 478                 case ACL_USER:
 479                         if (fap->acl_entry[i].ae_id != current->fsuid)
 480                                 continue;
 481                         matched.ae_tag = ACL_USER;
 482                         matched.ae_perm = allows;
 483                         break;
 484                 case ACL_GROUP_OBJ:
 485                         if ((matched.ae_tag == ACL_GROUP_OBJ ||
 486                             matched.ae_tag == ACL_GROUP) && !allows)
 487                                 continue;
 488                         if (!in_group_p(fgid))
 489                                 continue;
 490                         matched.ae_tag = ACL_GROUP_OBJ;
 491                         matched.ae_perm = allows;
 492                         break;
 493                 case ACL_GROUP:
 494                         if ((matched.ae_tag == ACL_GROUP_OBJ ||
 495                             matched.ae_tag == ACL_GROUP) && !allows)
 496                                 continue;
 497                         if (!in_group_p(fap->acl_entry[i].ae_id))
 498                                 continue;
 499                         matched.ae_tag = ACL_GROUP;
 500                         matched.ae_perm = allows;
 501                         break;
 502                 case ACL_MASK:
 503                         maskallows = allows;
 504                         break;
 505                 case ACL_OTHER:
 506                         if (matched.ae_tag != 0)
 507                                 continue;
 508                         matched.ae_tag = ACL_OTHER;
 509                         matched.ae_perm = allows;
 510                         break;
 511                 }
 512         }
 513         /*
 514          * First possibility is that no matched entry allows access.
 515          * The capability to override DAC may exist, so check for it.
 516          */
 517         switch (matched.ae_tag) {
 518         case ACL_OTHER:
 519         case ACL_USER_OBJ:
 520                 if (matched.ae_perm)
 521                         return 0;
 522                 break;
 523         case ACL_USER:
 524         case ACL_GROUP_OBJ:
 525         case ACL_GROUP:
 526                 if (maskallows && matched.ae_perm)
 527                         return 0;
 528                 break;
 529         case 0:
 530                 break;
 531         }
 532
 533         return xfs_acl_capability_check(md, cr);
 534 }
 535
 536 /*
 537  * ACL validity checker.
 538  *   This acl validation routine checks each ACL entry read in makes sense.
 539  */
 540 STATIC int
 541 xfs_acl_invalid(
 542         xfs_acl_t       *aclp)
 543 {
 544         xfs_acl_entry_t *entry, *e;
 545         int             user = 0, group = 0, other = 0, mask = 0;
 546         int             mask_required = 0;
 547         int             i, j;
 548
 549         if (!aclp)
 550                 goto acl_invalid;
 551
 552         if (aclp->acl_cnt > XFS_ACL_MAX_ENTRIES)
 553                 goto acl_invalid;
 554
 555         for (i = 0; i < aclp->acl_cnt; i++) {
 556                 entry = &aclp->acl_entry[i];
 557                 switch (entry->ae_tag) {
 558                 case ACL_USER_OBJ:
 559                         if (user++)
 560                                 goto acl_invalid;
 561                         break;
 562                 case ACL_GROUP_OBJ:
 563                         if (group++)
 564                                 goto acl_invalid;
 565                         break;
 566                 case ACL_OTHER:
 567                         if (other++)
 568                                 goto acl_invalid;
 569                         break;
 570                 case ACL_USER:
 571                 case ACL_GROUP:
 572                         for (j = i + 1; j < aclp->acl_cnt; j++) {
 573                                 e = &aclp->acl_entry[j];
 574                                 if (e->ae_id == entry->ae_id &&
 575                                     e->ae_tag == entry->ae_tag)
 576                                         goto acl_invalid;
 577                         }
 578                         mask_required++;
 579                         break;
 580                 case ACL_MASK:
 581                         if (mask++)
 582                                 goto acl_invalid;
 583                         break;
 584                 default:
 585                         goto acl_invalid;
 586                 }
 587         }
 588         if (!user || !group || !other || (mask_required && !mask))
 589                 goto acl_invalid;
 590         else
 591                 return 0;
 592 acl_invalid:
 593         return EINVAL;
 594 }
 595
 596 /*
 597  * Do ACL endian conversion.
 598  */
 599 STATIC void
 600 xfs_acl_get_endian(
 601         xfs_acl_t       *aclp)
 602 {
 603         xfs_acl_entry_t *ace, *end;
 604
 605         INT_SET(aclp->acl_cnt, ARCH_CONVERT, aclp->acl_cnt);
 606         end = &aclp->acl_entry[0]+aclp->acl_cnt;
 607         for (ace = &aclp->acl_entry[0]; ace < end; ace++) {
 608                 INT_SET(ace->ae_tag, ARCH_CONVERT, ace->ae_tag);
 609                 INT_SET(ace->ae_id, ARCH_CONVERT, ace->ae_id);
 610                 INT_SET(ace->ae_perm, ARCH_CONVERT, ace->ae_perm);
 611         }
 612 }
 613
 614 /*
 615  * Get the ACL from the EA and do endian conversion.
 616  */
 617 STATIC void
 618 xfs_acl_get_attr(
 619         vnode_t         *vp,
 620         xfs_acl_t       *aclp,
 621         int             kind,
 622         int             flags,
 623         int             *error)
 624 {
 625         int             len = sizeof(xfs_acl_t);
 626
 627         ASSERT((flags & ATTR_KERNOVAL) ? (aclp == NULL) : 1);
 628         flags |= ATTR_ROOT;
 629         VOP_ATTR_GET(vp,
 630                 kind == _ACL_TYPE_ACCESS ? SGI_ACL_FILE : SGI_ACL_DEFAULT,
 631                 (char *)aclp, &len, flags, sys_cred, *error);
 632         if (*error || (flags & ATTR_KERNOVAL))
 633                 return;
 634         xfs_acl_get_endian(aclp);
 635 }
 636
 637 /*
 638  * Set the EA with the ACL and do endian conversion.
 639  */
 640 STATIC void
 641 xfs_acl_set_attr(
 642         vnode_t         *vp,
 643         xfs_acl_t       *aclp,
 644         int             kind,
 645         int             *error)
 646 {
 647         xfs_acl_entry_t *ace, *newace, *end;
 648         xfs_acl_t       *newacl;
 649         int             len;
 650
 651         if (!(_ACL_ALLOC(newacl))) {
 652                 *error = ENOMEM;
 653                 return;
 654         }
 655
 656         len = sizeof(xfs_acl_t) -
 657               (sizeof(xfs_acl_entry_t) * (XFS_ACL_MAX_ENTRIES - aclp->acl_cnt));
 658         end = &aclp->acl_entry[0]+aclp->acl_cnt;
 659         for (ace = &aclp->acl_entry[0], newace = &newacl->acl_entry[0];
 660              ace < end;
 661              ace++, newace++) {
 662                 INT_SET(newace->ae_tag, ARCH_CONVERT, ace->ae_tag);
 663                 INT_SET(newace->ae_id, ARCH_CONVERT, ace->ae_id);
 664                 INT_SET(newace->ae_perm, ARCH_CONVERT, ace->ae_perm);
 665         }
 666         INT_SET(newacl->acl_cnt, ARCH_CONVERT, aclp->acl_cnt);
 667         VOP_ATTR_SET(vp,
 668                 kind == _ACL_TYPE_ACCESS ? SGI_ACL_FILE: SGI_ACL_DEFAULT,
 669                 (char *)newacl, len, ATTR_ROOT, sys_cred, *error);
 670         _ACL_FREE(newacl);
 671 }
 672
 673 int
 674 xfs_acl_vtoacl(
 675         vnode_t         *vp,
 676         xfs_acl_t       *access_acl,
 677         xfs_acl_t       *default_acl)
 678 {
 679         vattr_t         va;
 680         int             error = 0;
 681
 682         if (access_acl) {
 683                 /*
 684                  * Get the Access ACL and the mode.  If either cannot
 685                  * be obtained for some reason, invalidate the access ACL.
 686                  */
 687                 xfs_acl_get_attr(vp, access_acl, _ACL_TYPE_ACCESS, 0, &error);
 688                 if (!error) {
 689                         /* Got the ACL, need the mode... */
 690                         va.va_mask = XFS_AT_MODE;
 691                         VOP_GETATTR(vp, &va, 0, sys_cred, error);
 692                 }
 693
 694                 if (error)
 695                         access_acl->acl_cnt = XFS_ACL_NOT_PRESENT;
 696                 else /* We have a good ACL and the file mode, synchronize. */
 697                         xfs_acl_sync_mode(va.va_mode, access_acl);
 698         }
 699
 700         if (default_acl) {
 701                 xfs_acl_get_attr(vp, default_acl, _ACL_TYPE_DEFAULT, 0, &error);
 702                 if (error)
 703                         default_acl->acl_cnt = XFS_ACL_NOT_PRESENT;
 704         }
 705         return error;
 706 }
 707
 708 /*
 709  * This function retrieves the parent directory's acl, processes it
 710  * and lets the child inherit the acl(s) that it should.
 711  */
 712 int
 713 xfs_acl_inherit(
 714         vnode_t         *vp,
 715         vattr_t         *vap,
 716         xfs_acl_t       *pdaclp)
 717 {
 718         xfs_acl_t       *cacl;
 719         int             error = 0;
 720         int             basicperms = 0;
 721
 722         /*
 723          * If the parent does not have a default ACL, or it's an
 724          * invalid ACL, we're done.
 725          */
 726         if (!vp)
 727                 return 0;
 728         if (!pdaclp || xfs_acl_invalid(pdaclp))
 729                 return 0;
 730
 731         /*
 732          * Copy the default ACL of the containing directory to
 733          * the access ACL of the new file and use the mode that
 734          * was passed in to set up the correct initial values for
 735          * the u::,g::[m::], and o:: entries.  This is what makes
 736          * umask() "work" with ACL's.
 737          */
 738
 739         if (!(_ACL_ALLOC(cacl)))
 740                 return ENOMEM;
 741
 742         memcpy(cacl, pdaclp, sizeof(xfs_acl_t));
 743         xfs_acl_filter_mode(vap->va_mode, cacl);
 744         xfs_acl_setmode(vp, cacl, &basicperms);
 745
 746         /*
 747          * Set the Default and Access ACL on the file.  The mode is already
 748          * set on the file, so we don't need to worry about that.
 749          *
 750          * If the new file is a directory, its default ACL is a copy of
 751          * the containing directory's default ACL.
 752          */
 753         if (vp->v_type == VDIR)
 754                 xfs_acl_set_attr(vp, pdaclp, _ACL_TYPE_DEFAULT, &error);
 755         if (!error && !basicperms)
 756                 xfs_acl_set_attr(vp, cacl, _ACL_TYPE_ACCESS, &error);
 757         _ACL_FREE(cacl);
 758         return error;
 759 }
 760
 761 /*
 762  * Set up the correct mode on the file based on the supplied ACL.  This
 763  * makes sure that the mode on the file reflects the state of the
 764  * u::,g::[m::], and o:: entries in the ACL.  Since the mode is where
 765  * the ACL is going to get the permissions for these entries, we must
 766  * synchronize the mode whenever we set the ACL on a file.
 767  */
 768 STATIC int
 769 xfs_acl_setmode(
 770         vnode_t         *vp,
 771         xfs_acl_t       *acl,
 772         int             *basicperms)
 773 {
 774         vattr_t         va;
 775         xfs_acl_entry_t *ap;
 776         xfs_acl_entry_t *gap = NULL;
 777         int             i, error, nomask = 1;
 778
 779         *basicperms = 1;
 780
 781         if (acl->acl_cnt == XFS_ACL_NOT_PRESENT)
 782                 return 0;
 783
 784         /*
 785          * Copy the u::, g::, o::, and m:: bits from the ACL into the
 786          * mode.  The m:: bits take precedence over the g:: bits.
 787          */
 788         va.va_mask = XFS_AT_MODE;
 789         VOP_GETATTR(vp, &va, 0, sys_cred, error);
 790         if (error)
 791                 return error;
 792
 793         va.va_mask = XFS_AT_MODE;
 794         va.va_mode &= ~(S_IRWXU|S_IRWXG|S_IRWXO);
 795         ap = acl->acl_entry;
 796         for (i = 0; i < acl->acl_cnt; ++i) {
 797                 switch (ap->ae_tag) {
 798                 case ACL_USER_OBJ:
 799                         va.va_mode |= ap->ae_perm << 6;
 800                         break;
 801                 case ACL_GROUP_OBJ:
 802                         gap = ap;
 803                         break;
 804                 case ACL_MASK:  /* more than just standard modes */
 805                         nomask = 0;
 806                         va.va_mode |= ap->ae_perm << 3;
 807                         *basicperms = 0;
 808                         break;
 809                 case ACL_OTHER:
 810                         va.va_mode |= ap->ae_perm;
 811                         break;
 812                 default:        /* more than just standard modes */
 813                         *basicperms = 0;
 814                         break;
 815                 }
 816                 ap++;
 817         }
 818
 819         /* Set the group bits from ACL_GROUP_OBJ if there's no ACL_MASK */
 820         if (gap && nomask)
 821                 va.va_mode |= gap->ae_perm << 3;
 822
 823         VOP_SETATTR(vp, &va, 0, sys_cred, error);
 824         return error;
 825 }
 826
 827 /*
 828  * The permissions for the special ACL entries (u::, g::[m::], o::) are
 829  * actually stored in the file mode (if there is both a group and a mask,
 830  * the group is stored in the ACL entry and the mask is stored on the file).
 831  * This allows the mode to remain automatically in sync with the ACL without
 832  * the need for a call-back to the ACL system at every point where the mode
 833  * could change.  This function takes the permissions from the specified mode
 834  * and places it in the supplied ACL.
 835  *
 836  * This implementation draws its validity from the fact that, when the ACL
 837  * was assigned, the mode was copied from the ACL.
 838  * If the mode did not change, therefore, the mode remains exactly what was
 839  * taken from the special ACL entries at assignment.
 840  * If a subsequent chmod() was done, the POSIX spec says that the change in
 841  * mode must cause an update to the ACL seen at user level and used for
 842  * access checks.  Before and after a mode change, therefore, the file mode
 843  * most accurately reflects what the special ACL entries should permit/deny.
 844  *
 845  * CAVEAT: If someone sets the SGI_ACL_FILE attribute directly,
 846  *         the existing mode bits will override whatever is in the
 847  *         ACL. Similarly, if there is a pre-existing ACL that was
 848  *         never in sync with its mode (owing to a bug in 6.5 and
 849  *         before), it will now magically (or mystically) be
 850  *         synchronized.  This could cause slight astonishment, but
 851  *         it is better than inconsistent permissions.
 852  *
 853  * The supplied ACL is a template that may contain any combination
 854  * of special entries.  These are treated as place holders when we fill
 855  * out the ACL.  This routine does not add or remove special entries, it
 856  * simply unites each special entry with its associated set of permissions.
 857  */
 858 STATIC void
 859 xfs_acl_sync_mode(
 860         mode_t          mode,
 861         xfs_acl_t       *acl)
 862 {
 863         int             i, nomask = 1;
 864         xfs_acl_entry_t *ap;
 865         xfs_acl_entry_t *gap = NULL;
 866
 867         /*
 868          * Set ACL entries. POSIX1003.1eD16 requires that the MASK
 869          * be set instead of the GROUP entry, if there is a MASK.
 870          */
 871         for (ap = acl->acl_entry, i = 0; i < acl->acl_cnt; ap++, i++) {
 872                 switch (ap->ae_tag) {
 873                 case ACL_USER_OBJ:
 874                         ap->ae_perm = (mode >> 6) & 0x7;
 875                         break;
 876                 case ACL_GROUP_OBJ:
 877                         gap = ap;
 878                         break;
 879                 case ACL_MASK:
 880                         nomask = 0;
 881                         ap->ae_perm = (mode >> 3) & 0x7;
 882                         break;
 883                 case ACL_OTHER:
 884                         ap->ae_perm = mode & 0x7;
 885                         break;
 886                 default:
 887                         break;
 888                 }
 889         }
 890         /* Set the ACL_GROUP_OBJ if there's no ACL_MASK */
 891         if (gap && nomask)
 892                 gap->ae_perm = (mode >> 3) & 0x7;
 893 }
 894
 895 /*
 896  * When inheriting an Access ACL from a directory Default ACL,
 897  * the ACL bits are set to the intersection of the ACL default
 898  * permission bits and the file permission bits in mode. If there
 899  * are no permission bits on the file then we must not give them
 900  * the ACL. This is what what makes umask() work with ACLs.
 901  */
 902 STATIC void
 903 xfs_acl_filter_mode(
 904         mode_t          mode,
 905         xfs_acl_t       *acl)
 906 {
 907         int             i, nomask = 1;
 908         xfs_acl_entry_t *ap;
 909         xfs_acl_entry_t *gap = NULL;
 910
 911         /*
 912          * Set ACL entries. POSIX1003.1eD16 requires that the MASK
 913          * be merged with GROUP entry, if there is a MASK.
 914          */
 915         for (ap = acl->acl_entry, i = 0; i < acl->acl_cnt; ap++, i++) {
 916                 switch (ap->ae_tag) {
 917                 case ACL_USER_OBJ:
 918                         ap->ae_perm &= (mode >> 6) & 0x7;
 919                         break;
 920                 case ACL_GROUP_OBJ:
 921                         gap = ap;
 922                         break;
 923                 case ACL_MASK:
 924                         nomask = 0;
 925                         ap->ae_perm &= (mode >> 3) & 0x7;
 926                         break;
 927                 case ACL_OTHER:
 928                         ap->ae_perm &= mode & 0x7;
 929                         break;
 930                 default:
 931                         break;
 932                 }
 933         }
 934         /* Set the ACL_GROUP_OBJ if there's no ACL_MASK */
 935         if (gap && nomask)
 936                 gap->ae_perm &= (mode >> 3) & 0x7;
 937 }