Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2008, Christoph Hellwig |
| 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_acl.h" |
| 20 | #include "xfs_attr.h" |
| 21 | #include "xfs_bmap_btree.h" |
| 22 | #include "xfs_inode.h" |
| 23 | #include "xfs_vnodeops.h" |
| 24 | #include <linux/xattr.h> |
| 25 | #include <linux/posix_acl_xattr.h> |
| 26 | |
| 27 | |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 28 | /* |
| 29 | * Locking scheme: |
| 30 | * - all ACL updates are protected by inode->i_mutex, which is taken before |
| 31 | * calling into this file. |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 32 | */ |
| 33 | |
| 34 | STATIC struct posix_acl * |
| 35 | xfs_acl_from_disk(struct xfs_acl *aclp) |
| 36 | { |
| 37 | struct posix_acl_entry *acl_e; |
| 38 | struct posix_acl *acl; |
| 39 | struct xfs_acl_entry *ace; |
| 40 | int count, i; |
| 41 | |
| 42 | count = be32_to_cpu(aclp->acl_cnt); |
| 43 | |
| 44 | acl = posix_acl_alloc(count, GFP_KERNEL); |
| 45 | if (!acl) |
| 46 | return ERR_PTR(-ENOMEM); |
| 47 | |
| 48 | for (i = 0; i < count; i++) { |
| 49 | acl_e = &acl->a_entries[i]; |
| 50 | ace = &aclp->acl_entry[i]; |
| 51 | |
| 52 | /* |
| 53 | * The tag is 32 bits on disk and 16 bits in core. |
| 54 | * |
| 55 | * Because every access to it goes through the core |
| 56 | * format first this is not a problem. |
| 57 | */ |
| 58 | acl_e->e_tag = be32_to_cpu(ace->ae_tag); |
| 59 | acl_e->e_perm = be16_to_cpu(ace->ae_perm); |
| 60 | |
| 61 | switch (acl_e->e_tag) { |
| 62 | case ACL_USER: |
| 63 | case ACL_GROUP: |
| 64 | acl_e->e_id = be32_to_cpu(ace->ae_id); |
| 65 | break; |
| 66 | case ACL_USER_OBJ: |
| 67 | case ACL_GROUP_OBJ: |
| 68 | case ACL_MASK: |
| 69 | case ACL_OTHER: |
| 70 | acl_e->e_id = ACL_UNDEFINED_ID; |
| 71 | break; |
| 72 | default: |
| 73 | goto fail; |
| 74 | } |
| 75 | } |
| 76 | return acl; |
| 77 | |
| 78 | fail: |
| 79 | posix_acl_release(acl); |
| 80 | return ERR_PTR(-EINVAL); |
| 81 | } |
| 82 | |
| 83 | STATIC void |
| 84 | xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl) |
| 85 | { |
| 86 | const struct posix_acl_entry *acl_e; |
| 87 | struct xfs_acl_entry *ace; |
| 88 | int i; |
| 89 | |
| 90 | aclp->acl_cnt = cpu_to_be32(acl->a_count); |
| 91 | for (i = 0; i < acl->a_count; i++) { |
| 92 | ace = &aclp->acl_entry[i]; |
| 93 | acl_e = &acl->a_entries[i]; |
| 94 | |
| 95 | ace->ae_tag = cpu_to_be32(acl_e->e_tag); |
| 96 | ace->ae_id = cpu_to_be32(acl_e->e_id); |
| 97 | ace->ae_perm = cpu_to_be16(acl_e->e_perm); |
| 98 | } |
| 99 | } |
| 100 | |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 101 | struct posix_acl * |
| 102 | xfs_get_acl(struct inode *inode, int type) |
| 103 | { |
| 104 | struct xfs_inode *ip = XFS_I(inode); |
Al Viro | 1cbd20d | 2009-06-09 13:29:39 -0400 | [diff] [blame] | 105 | struct posix_acl *acl; |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 106 | struct xfs_acl *xfs_acl; |
| 107 | int len = sizeof(struct xfs_acl); |
| 108 | char *ea_name; |
| 109 | int error; |
| 110 | |
Al Viro | 1cbd20d | 2009-06-09 13:29:39 -0400 | [diff] [blame] | 111 | acl = get_cached_acl(inode, type); |
| 112 | if (acl != ACL_NOT_CACHED) |
| 113 | return acl; |
| 114 | |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 115 | switch (type) { |
| 116 | case ACL_TYPE_ACCESS: |
| 117 | ea_name = SGI_ACL_FILE; |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 118 | break; |
| 119 | case ACL_TYPE_DEFAULT: |
| 120 | ea_name = SGI_ACL_DEFAULT; |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 121 | break; |
| 122 | default: |
Al Viro | 1cbd20d | 2009-06-09 13:29:39 -0400 | [diff] [blame] | 123 | BUG(); |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 124 | } |
| 125 | |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 126 | /* |
| 127 | * If we have a cached ACLs value just return it, not need to |
| 128 | * go out to the disk. |
| 129 | */ |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 130 | |
| 131 | xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL); |
| 132 | if (!xfs_acl) |
| 133 | return ERR_PTR(-ENOMEM); |
| 134 | |
| 135 | error = -xfs_attr_get(ip, ea_name, (char *)xfs_acl, &len, ATTR_ROOT); |
| 136 | if (error) { |
| 137 | /* |
| 138 | * If the attribute doesn't exist make sure we have a negative |
| 139 | * cache entry, for any other error assume it is transient and |
Al Viro | 1cbd20d | 2009-06-09 13:29:39 -0400 | [diff] [blame] | 140 | * leave the cache entry as ACL_NOT_CACHED. |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 141 | */ |
| 142 | if (error == -ENOATTR) { |
| 143 | acl = NULL; |
| 144 | goto out_update_cache; |
| 145 | } |
| 146 | goto out; |
| 147 | } |
| 148 | |
| 149 | acl = xfs_acl_from_disk(xfs_acl); |
| 150 | if (IS_ERR(acl)) |
| 151 | goto out; |
| 152 | |
| 153 | out_update_cache: |
Al Viro | 1cbd20d | 2009-06-09 13:29:39 -0400 | [diff] [blame] | 154 | set_cached_acl(inode, type, acl); |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 155 | out: |
| 156 | kfree(xfs_acl); |
| 157 | return acl; |
| 158 | } |
| 159 | |
| 160 | STATIC int |
| 161 | xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl) |
| 162 | { |
| 163 | struct xfs_inode *ip = XFS_I(inode); |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 164 | char *ea_name; |
| 165 | int error; |
| 166 | |
| 167 | if (S_ISLNK(inode->i_mode)) |
| 168 | return -EOPNOTSUPP; |
| 169 | |
| 170 | switch (type) { |
| 171 | case ACL_TYPE_ACCESS: |
| 172 | ea_name = SGI_ACL_FILE; |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 173 | break; |
| 174 | case ACL_TYPE_DEFAULT: |
| 175 | if (!S_ISDIR(inode->i_mode)) |
| 176 | return acl ? -EACCES : 0; |
| 177 | ea_name = SGI_ACL_DEFAULT; |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 178 | break; |
| 179 | default: |
| 180 | return -EINVAL; |
| 181 | } |
| 182 | |
| 183 | if (acl) { |
| 184 | struct xfs_acl *xfs_acl; |
| 185 | int len; |
| 186 | |
| 187 | xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL); |
| 188 | if (!xfs_acl) |
| 189 | return -ENOMEM; |
| 190 | |
| 191 | xfs_acl_to_disk(xfs_acl, acl); |
| 192 | len = sizeof(struct xfs_acl) - |
| 193 | (sizeof(struct xfs_acl_entry) * |
| 194 | (XFS_ACL_MAX_ENTRIES - acl->a_count)); |
| 195 | |
| 196 | error = -xfs_attr_set(ip, ea_name, (char *)xfs_acl, |
| 197 | len, ATTR_ROOT); |
| 198 | |
| 199 | kfree(xfs_acl); |
| 200 | } else { |
| 201 | /* |
| 202 | * A NULL ACL argument means we want to remove the ACL. |
| 203 | */ |
| 204 | error = -xfs_attr_remove(ip, ea_name, ATTR_ROOT); |
| 205 | |
| 206 | /* |
| 207 | * If the attribute didn't exist to start with that's fine. |
| 208 | */ |
| 209 | if (error == -ENOATTR) |
| 210 | error = 0; |
| 211 | } |
| 212 | |
| 213 | if (!error) |
Al Viro | 1cbd20d | 2009-06-09 13:29:39 -0400 | [diff] [blame] | 214 | set_cached_acl(inode, type, acl); |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 215 | return error; |
| 216 | } |
| 217 | |
| 218 | int |
| 219 | xfs_check_acl(struct inode *inode, int mask) |
| 220 | { |
| 221 | struct xfs_inode *ip = XFS_I(inode); |
| 222 | struct posix_acl *acl; |
| 223 | int error = -EAGAIN; |
| 224 | |
| 225 | xfs_itrace_entry(ip); |
| 226 | |
| 227 | /* |
| 228 | * If there is no attribute fork no ACL exists on this inode and |
| 229 | * we can skip the whole exercise. |
| 230 | */ |
| 231 | if (!XFS_IFORK_Q(ip)) |
| 232 | return -EAGAIN; |
| 233 | |
| 234 | acl = xfs_get_acl(inode, ACL_TYPE_ACCESS); |
| 235 | if (IS_ERR(acl)) |
| 236 | return PTR_ERR(acl); |
| 237 | if (acl) { |
| 238 | error = posix_acl_permission(inode, acl, mask); |
| 239 | posix_acl_release(acl); |
| 240 | } |
| 241 | |
| 242 | return error; |
| 243 | } |
| 244 | |
| 245 | static int |
| 246 | xfs_set_mode(struct inode *inode, mode_t mode) |
| 247 | { |
| 248 | int error = 0; |
| 249 | |
| 250 | if (mode != inode->i_mode) { |
| 251 | struct iattr iattr; |
| 252 | |
| 253 | iattr.ia_valid = ATTR_MODE; |
| 254 | iattr.ia_mode = mode; |
| 255 | |
| 256 | error = -xfs_setattr(XFS_I(inode), &iattr, XFS_ATTR_NOACL); |
| 257 | } |
| 258 | |
| 259 | return error; |
| 260 | } |
| 261 | |
| 262 | static int |
| 263 | xfs_acl_exists(struct inode *inode, char *name) |
| 264 | { |
| 265 | int len = sizeof(struct xfs_acl); |
| 266 | |
| 267 | return (xfs_attr_get(XFS_I(inode), name, NULL, &len, |
| 268 | ATTR_ROOT|ATTR_KERNOVAL) == 0); |
| 269 | } |
| 270 | |
| 271 | int |
| 272 | posix_acl_access_exists(struct inode *inode) |
| 273 | { |
| 274 | return xfs_acl_exists(inode, SGI_ACL_FILE); |
| 275 | } |
| 276 | |
| 277 | int |
| 278 | posix_acl_default_exists(struct inode *inode) |
| 279 | { |
| 280 | if (!S_ISDIR(inode->i_mode)) |
| 281 | return 0; |
| 282 | return xfs_acl_exists(inode, SGI_ACL_DEFAULT); |
| 283 | } |
| 284 | |
| 285 | /* |
| 286 | * No need for i_mutex because the inode is not yet exposed to the VFS. |
| 287 | */ |
| 288 | int |
| 289 | xfs_inherit_acl(struct inode *inode, struct posix_acl *default_acl) |
| 290 | { |
| 291 | struct posix_acl *clone; |
| 292 | mode_t mode; |
| 293 | int error = 0, inherit = 0; |
| 294 | |
| 295 | if (S_ISDIR(inode->i_mode)) { |
| 296 | error = xfs_set_acl(inode, ACL_TYPE_DEFAULT, default_acl); |
| 297 | if (error) |
| 298 | return error; |
| 299 | } |
| 300 | |
| 301 | clone = posix_acl_clone(default_acl, GFP_KERNEL); |
| 302 | if (!clone) |
| 303 | return -ENOMEM; |
| 304 | |
| 305 | mode = inode->i_mode; |
| 306 | error = posix_acl_create_masq(clone, &mode); |
| 307 | if (error < 0) |
| 308 | goto out_release_clone; |
| 309 | |
| 310 | /* |
| 311 | * If posix_acl_create_masq returns a positive value we need to |
| 312 | * inherit a permission that can't be represented using the Unix |
| 313 | * mode bits and we actually need to set an ACL. |
| 314 | */ |
| 315 | if (error > 0) |
| 316 | inherit = 1; |
| 317 | |
| 318 | error = xfs_set_mode(inode, mode); |
| 319 | if (error) |
| 320 | goto out_release_clone; |
| 321 | |
| 322 | if (inherit) |
| 323 | error = xfs_set_acl(inode, ACL_TYPE_ACCESS, clone); |
| 324 | |
| 325 | out_release_clone: |
| 326 | posix_acl_release(clone); |
| 327 | return error; |
| 328 | } |
| 329 | |
| 330 | int |
| 331 | xfs_acl_chmod(struct inode *inode) |
| 332 | { |
| 333 | struct posix_acl *acl, *clone; |
| 334 | int error; |
| 335 | |
| 336 | if (S_ISLNK(inode->i_mode)) |
| 337 | return -EOPNOTSUPP; |
| 338 | |
| 339 | acl = xfs_get_acl(inode, ACL_TYPE_ACCESS); |
| 340 | if (IS_ERR(acl) || !acl) |
| 341 | return PTR_ERR(acl); |
| 342 | |
| 343 | clone = posix_acl_clone(acl, GFP_KERNEL); |
| 344 | posix_acl_release(acl); |
| 345 | if (!clone) |
| 346 | return -ENOMEM; |
| 347 | |
| 348 | error = posix_acl_chmod_masq(clone, inode->i_mode); |
| 349 | if (!error) |
| 350 | error = xfs_set_acl(inode, ACL_TYPE_ACCESS, clone); |
| 351 | |
| 352 | posix_acl_release(clone); |
| 353 | return error; |
| 354 | } |
| 355 | |
Christoph Hellwig | ef14f0c | 2009-06-10 17:07:47 +0200 | [diff] [blame] | 356 | /* |
| 357 | * System xattr handlers. |
| 358 | * |
| 359 | * Currently Posix ACLs are the only system namespace extended attribute |
| 360 | * handlers supported by XFS, so we just implement the handlers here. |
| 361 | * If we ever support other system extended attributes this will need |
| 362 | * some refactoring. |
| 363 | */ |
| 364 | |
| 365 | static int |
| 366 | xfs_decode_acl(const char *name) |
| 367 | { |
| 368 | if (strcmp(name, "posix_acl_access") == 0) |
| 369 | return ACL_TYPE_ACCESS; |
| 370 | else if (strcmp(name, "posix_acl_default") == 0) |
| 371 | return ACL_TYPE_DEFAULT; |
| 372 | return -EINVAL; |
| 373 | } |
| 374 | |
| 375 | static int |
| 376 | xfs_xattr_system_get(struct inode *inode, const char *name, |
| 377 | void *value, size_t size) |
| 378 | { |
| 379 | struct posix_acl *acl; |
| 380 | int type, error; |
| 381 | |
| 382 | type = xfs_decode_acl(name); |
| 383 | if (type < 0) |
| 384 | return type; |
| 385 | |
| 386 | acl = xfs_get_acl(inode, type); |
| 387 | if (IS_ERR(acl)) |
| 388 | return PTR_ERR(acl); |
| 389 | if (acl == NULL) |
| 390 | return -ENODATA; |
| 391 | |
| 392 | error = posix_acl_to_xattr(acl, value, size); |
| 393 | posix_acl_release(acl); |
| 394 | |
| 395 | return error; |
| 396 | } |
| 397 | |
| 398 | static int |
| 399 | xfs_xattr_system_set(struct inode *inode, const char *name, |
| 400 | const void *value, size_t size, int flags) |
| 401 | { |
| 402 | struct posix_acl *acl = NULL; |
| 403 | int error = 0, type; |
| 404 | |
| 405 | type = xfs_decode_acl(name); |
| 406 | if (type < 0) |
| 407 | return type; |
| 408 | if (flags & XATTR_CREATE) |
| 409 | return -EINVAL; |
| 410 | if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) |
| 411 | return value ? -EACCES : 0; |
| 412 | if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER)) |
| 413 | return -EPERM; |
| 414 | |
| 415 | if (!value) |
| 416 | goto set_acl; |
| 417 | |
| 418 | acl = posix_acl_from_xattr(value, size); |
| 419 | if (!acl) { |
| 420 | /* |
| 421 | * acl_set_file(3) may request that we set default ACLs with |
| 422 | * zero length -- defend (gracefully) against that here. |
| 423 | */ |
| 424 | goto out; |
| 425 | } |
| 426 | if (IS_ERR(acl)) { |
| 427 | error = PTR_ERR(acl); |
| 428 | goto out; |
| 429 | } |
| 430 | |
| 431 | error = posix_acl_valid(acl); |
| 432 | if (error) |
| 433 | goto out_release; |
| 434 | |
| 435 | error = -EINVAL; |
| 436 | if (acl->a_count > XFS_ACL_MAX_ENTRIES) |
| 437 | goto out_release; |
| 438 | |
| 439 | if (type == ACL_TYPE_ACCESS) { |
| 440 | mode_t mode = inode->i_mode; |
| 441 | error = posix_acl_equiv_mode(acl, &mode); |
| 442 | |
| 443 | if (error <= 0) { |
| 444 | posix_acl_release(acl); |
| 445 | acl = NULL; |
| 446 | |
| 447 | if (error < 0) |
| 448 | return error; |
| 449 | } |
| 450 | |
| 451 | error = xfs_set_mode(inode, mode); |
| 452 | if (error) |
| 453 | goto out_release; |
| 454 | } |
| 455 | |
| 456 | set_acl: |
| 457 | error = xfs_set_acl(inode, type, acl); |
| 458 | out_release: |
| 459 | posix_acl_release(acl); |
| 460 | out: |
| 461 | return error; |
| 462 | } |
| 463 | |
| 464 | struct xattr_handler xfs_xattr_system_handler = { |
| 465 | .prefix = XATTR_SYSTEM_PREFIX, |
| 466 | .get = xfs_xattr_system_get, |
| 467 | .set = xfs_xattr_system_set, |
| 468 | }; |