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