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_format.h" 20 #include "xfs_log_format.h" 21 #include "xfs_trans_resv.h" 22 #include "xfs_ag.h" 23 #include "xfs_sb.h" 24 #include "xfs_mount.h" 25 #include "xfs_inode.h" 26 #include "xfs_acl.h" 27 #include "xfs_attr.h" 28 #include "xfs_trace.h" 29 #include <linux/slab.h> 30 #include <linux/xattr.h> 31 #include <linux/posix_acl_xattr.h> 32 33 34 /* 35 * Locking scheme: 36 * - all ACL updates are protected by inode->i_mutex, which is taken before 37 * calling into this file. 38 */ 39 40 STATIC struct posix_acl * 41 xfs_acl_from_disk( 42 struct xfs_acl *aclp, 43 int max_entries) 44 { 45 struct posix_acl_entry *acl_e; 46 struct posix_acl *acl; 47 struct xfs_acl_entry *ace; 48 unsigned int count, i; 49 50 count = be32_to_cpu(aclp->acl_cnt); 51 if (count > max_entries) 52 return ERR_PTR(-EFSCORRUPTED); 53 54 acl = posix_acl_alloc(count, GFP_KERNEL); 55 if (!acl) 56 return ERR_PTR(-ENOMEM); 57 58 for (i = 0; i < count; i++) { 59 acl_e = &acl->a_entries[i]; 60 ace = &aclp->acl_entry[i]; 61 62 /* 63 * The tag is 32 bits on disk and 16 bits in core. 64 * 65 * Because every access to it goes through the core 66 * format first this is not a problem. 67 */ 68 acl_e->e_tag = be32_to_cpu(ace->ae_tag); 69 acl_e->e_perm = be16_to_cpu(ace->ae_perm); 70 71 switch (acl_e->e_tag) { 72 case ACL_USER: 73 acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id)); 74 break; 75 case ACL_GROUP: 76 acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id)); 77 break; 78 case ACL_USER_OBJ: 79 case ACL_GROUP_OBJ: 80 case ACL_MASK: 81 case ACL_OTHER: 82 break; 83 default: 84 goto fail; 85 } 86 } 87 return acl; 88 89 fail: 90 posix_acl_release(acl); 91 return ERR_PTR(-EINVAL); 92 } 93 94 STATIC void 95 xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl) 96 { 97 const struct posix_acl_entry *acl_e; 98 struct xfs_acl_entry *ace; 99 int i; 100 101 aclp->acl_cnt = cpu_to_be32(acl->a_count); 102 for (i = 0; i < acl->a_count; i++) { 103 ace = &aclp->acl_entry[i]; 104 acl_e = &acl->a_entries[i]; 105 106 ace->ae_tag = cpu_to_be32(acl_e->e_tag); 107 switch (acl_e->e_tag) { 108 case ACL_USER: 109 ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid)); 110 break; 111 case ACL_GROUP: 112 ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid)); 113 break; 114 default: 115 ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID); 116 break; 117 } 118 119 ace->ae_perm = cpu_to_be16(acl_e->e_perm); 120 } 121 } 122 123 struct posix_acl * 124 xfs_get_acl(struct inode *inode, int type) 125 { 126 struct xfs_inode *ip = XFS_I(inode); 127 struct posix_acl *acl; 128 struct xfs_acl *xfs_acl; 129 unsigned char *ea_name; 130 int error; 131 int len; 132 133 acl = get_cached_acl(inode, type); 134 if (acl != ACL_NOT_CACHED) 135 return acl; 136 137 trace_xfs_get_acl(ip); 138 139 switch (type) { 140 case ACL_TYPE_ACCESS: 141 ea_name = SGI_ACL_FILE; 142 break; 143 case ACL_TYPE_DEFAULT: 144 ea_name = SGI_ACL_DEFAULT; 145 break; 146 default: 147 BUG(); 148 } 149 150 /* 151 * If we have a cached ACLs value just return it, not need to 152 * go out to the disk. 153 */ 154 len = XFS_ACL_MAX_SIZE(ip->i_mount); 155 xfs_acl = kmem_zalloc_large(len, KM_SLEEP); 156 if (!xfs_acl) 157 return ERR_PTR(-ENOMEM); 158 159 error = -xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl, 160 &len, ATTR_ROOT); 161 if (error) { 162 /* 163 * If the attribute doesn't exist make sure we have a negative 164 * cache entry, for any other error assume it is transient and 165 * leave the cache entry as ACL_NOT_CACHED. 166 */ 167 if (error == -ENOATTR) { 168 acl = NULL; 169 goto out_update_cache; 170 } 171 goto out; 172 } 173 174 acl = xfs_acl_from_disk(xfs_acl, XFS_ACL_MAX_ENTRIES(ip->i_mount)); 175 if (IS_ERR(acl)) 176 goto out; 177 178 out_update_cache: 179 set_cached_acl(inode, type, acl); 180 out: 181 kmem_free(xfs_acl); 182 return acl; 183 } 184 185 STATIC int 186 xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl) 187 { 188 struct xfs_inode *ip = XFS_I(inode); 189 unsigned char *ea_name; 190 int error; 191 192 if (S_ISLNK(inode->i_mode)) 193 return -EOPNOTSUPP; 194 195 switch (type) { 196 case ACL_TYPE_ACCESS: 197 ea_name = SGI_ACL_FILE; 198 break; 199 case ACL_TYPE_DEFAULT: 200 if (!S_ISDIR(inode->i_mode)) 201 return acl ? -EACCES : 0; 202 ea_name = SGI_ACL_DEFAULT; 203 break; 204 default: 205 return -EINVAL; 206 } 207 208 if (acl) { 209 struct xfs_acl *xfs_acl; 210 int len = XFS_ACL_MAX_SIZE(ip->i_mount); 211 212 xfs_acl = kmem_zalloc_large(len, KM_SLEEP); 213 if (!xfs_acl) 214 return -ENOMEM; 215 216 xfs_acl_to_disk(xfs_acl, acl); 217 218 /* subtract away the unused acl entries */ 219 len -= sizeof(struct xfs_acl_entry) * 220 (XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count); 221 222 error = -xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl, 223 len, ATTR_ROOT); 224 225 kmem_free(xfs_acl); 226 } else { 227 /* 228 * A NULL ACL argument means we want to remove the ACL. 229 */ 230 error = -xfs_attr_remove(ip, ea_name, ATTR_ROOT); 231 232 /* 233 * If the attribute didn't exist to start with that's fine. 234 */ 235 if (error == -ENOATTR) 236 error = 0; 237 } 238 239 if (!error) 240 set_cached_acl(inode, type, acl); 241 return error; 242 } 243 244 static int 245 xfs_set_mode(struct inode *inode, umode_t mode) 246 { 247 int error = 0; 248 249 if (mode != inode->i_mode) { 250 struct iattr iattr; 251 252 iattr.ia_valid = ATTR_MODE | ATTR_CTIME; 253 iattr.ia_mode = mode; 254 iattr.ia_ctime = current_fs_time(inode->i_sb); 255 256 error = -xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL); 257 } 258 259 return error; 260 } 261 262 static int 263 xfs_acl_exists(struct inode *inode, unsigned char *name) 264 { 265 int len = XFS_ACL_MAX_SIZE(XFS_M(inode->i_sb)); 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 *acl) 290 { 291 umode_t mode = inode->i_mode; 292 int error = 0, inherit = 0; 293 294 if (S_ISDIR(inode->i_mode)) { 295 error = xfs_set_acl(inode, ACL_TYPE_DEFAULT, acl); 296 if (error) 297 goto out; 298 } 299 300 error = posix_acl_create(&acl, GFP_KERNEL, &mode); 301 if (error < 0) 302 return error; 303 304 /* 305 * If posix_acl_create returns a positive value we need to 306 * inherit a permission that can't be represented using the Unix 307 * mode bits and we actually need to set an ACL. 308 */ 309 if (error > 0) 310 inherit = 1; 311 312 error = xfs_set_mode(inode, mode); 313 if (error) 314 goto out; 315 316 if (inherit) 317 error = xfs_set_acl(inode, ACL_TYPE_ACCESS, acl); 318 319 out: 320 posix_acl_release(acl); 321 return error; 322 } 323 324 int 325 xfs_acl_chmod(struct inode *inode) 326 { 327 struct posix_acl *acl; 328 int error; 329 330 if (S_ISLNK(inode->i_mode)) 331 return -EOPNOTSUPP; 332 333 acl = xfs_get_acl(inode, ACL_TYPE_ACCESS); 334 if (IS_ERR(acl) || !acl) 335 return PTR_ERR(acl); 336 337 error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode); 338 if (error) 339 return error; 340 341 error = xfs_set_acl(inode, ACL_TYPE_ACCESS, acl); 342 posix_acl_release(acl); 343 return error; 344 } 345 346 static int 347 xfs_xattr_acl_get(struct dentry *dentry, const char *name, 348 void *value, size_t size, int type) 349 { 350 struct posix_acl *acl; 351 int error; 352 353 acl = xfs_get_acl(dentry->d_inode, type); 354 if (IS_ERR(acl)) 355 return PTR_ERR(acl); 356 if (acl == NULL) 357 return -ENODATA; 358 359 error = posix_acl_to_xattr(&init_user_ns, acl, value, size); 360 posix_acl_release(acl); 361 362 return error; 363 } 364 365 static int 366 xfs_xattr_acl_set(struct dentry *dentry, const char *name, 367 const void *value, size_t size, int flags, int type) 368 { 369 struct inode *inode = dentry->d_inode; 370 struct posix_acl *acl = NULL; 371 int error = 0; 372 373 if (flags & XATTR_CREATE) 374 return -EINVAL; 375 if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) 376 return value ? -EACCES : 0; 377 if (!inode_owner_or_capable(inode)) 378 return -EPERM; 379 380 if (!value) 381 goto set_acl; 382 383 acl = posix_acl_from_xattr(&init_user_ns, value, size); 384 if (!acl) { 385 /* 386 * acl_set_file(3) may request that we set default ACLs with 387 * zero length -- defend (gracefully) against that here. 388 */ 389 goto out; 390 } 391 if (IS_ERR(acl)) { 392 error = PTR_ERR(acl); 393 goto out; 394 } 395 396 error = posix_acl_valid(acl); 397 if (error) 398 goto out_release; 399 400 error = -EINVAL; 401 if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb))) 402 goto out_release; 403 404 if (type == ACL_TYPE_ACCESS) { 405 umode_t mode = inode->i_mode; 406 error = posix_acl_equiv_mode(acl, &mode); 407 408 if (error <= 0) { 409 posix_acl_release(acl); 410 acl = NULL; 411 412 if (error < 0) 413 return error; 414 } 415 416 error = xfs_set_mode(inode, mode); 417 if (error) 418 goto out_release; 419 } 420 421 set_acl: 422 error = xfs_set_acl(inode, type, acl); 423 out_release: 424 posix_acl_release(acl); 425 out: 426 return error; 427 } 428 429 const struct xattr_handler xfs_xattr_acl_access_handler = { 430 .prefix = POSIX_ACL_XATTR_ACCESS, 431 .flags = ACL_TYPE_ACCESS, 432 .get = xfs_xattr_acl_get, 433 .set = xfs_xattr_acl_set, 434 }; 435 436 const struct xattr_handler xfs_xattr_acl_default_handler = { 437 .prefix = POSIX_ACL_XATTR_DEFAULT, 438 .flags = ACL_TYPE_DEFAULT, 439 .get = xfs_xattr_acl_get, 440 .set = xfs_xattr_acl_set, 441 }; 442