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