1 /* 2 * Copyright (C) 2007 Red Hat. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public 6 * License v2 as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 * General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public 14 * License along with this program; if not, write to the 15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, 16 * Boston, MA 021110-1307, USA. 17 */ 18 19 #include <linux/fs.h> 20 #include <linux/string.h> 21 #include <linux/xattr.h> 22 #include <linux/posix_acl_xattr.h> 23 #include <linux/posix_acl.h> 24 #include <linux/sched.h> 25 #include <linux/slab.h> 26 27 #include "ctree.h" 28 #include "btrfs_inode.h" 29 #include "xattr.h" 30 31 #ifdef CONFIG_BTRFS_FS_POSIX_ACL 32 33 static struct posix_acl *btrfs_get_acl(struct inode *inode, int type) 34 { 35 int size; 36 const char *name; 37 char *value = NULL; 38 struct posix_acl *acl; 39 40 if (!IS_POSIXACL(inode)) 41 return NULL; 42 43 acl = get_cached_acl(inode, type); 44 if (acl != ACL_NOT_CACHED) 45 return acl; 46 47 switch (type) { 48 case ACL_TYPE_ACCESS: 49 name = POSIX_ACL_XATTR_ACCESS; 50 break; 51 case ACL_TYPE_DEFAULT: 52 name = POSIX_ACL_XATTR_DEFAULT; 53 break; 54 default: 55 BUG(); 56 } 57 58 size = __btrfs_getxattr(inode, name, "", 0); 59 if (size > 0) { 60 value = kzalloc(size, GFP_NOFS); 61 if (!value) 62 return ERR_PTR(-ENOMEM); 63 size = __btrfs_getxattr(inode, name, value, size); 64 if (size > 0) { 65 acl = posix_acl_from_xattr(value, size); 66 if (IS_ERR(acl)) { 67 kfree(value); 68 return acl; 69 } 70 set_cached_acl(inode, type, acl); 71 } 72 kfree(value); 73 } else if (size == -ENOENT || size == -ENODATA || size == 0) { 74 /* FIXME, who returns -ENOENT? I think nobody */ 75 acl = NULL; 76 set_cached_acl(inode, type, acl); 77 } else { 78 acl = ERR_PTR(-EIO); 79 } 80 81 return acl; 82 } 83 84 static int btrfs_xattr_acl_get(struct dentry *dentry, const char *name, 85 void *value, size_t size, int type) 86 { 87 struct posix_acl *acl; 88 int ret = 0; 89 90 if (!IS_POSIXACL(dentry->d_inode)) 91 return -EOPNOTSUPP; 92 93 acl = btrfs_get_acl(dentry->d_inode, type); 94 95 if (IS_ERR(acl)) 96 return PTR_ERR(acl); 97 if (acl == NULL) 98 return -ENODATA; 99 ret = posix_acl_to_xattr(acl, value, size); 100 posix_acl_release(acl); 101 102 return ret; 103 } 104 105 /* 106 * Needs to be called with fs_mutex held 107 */ 108 static int btrfs_set_acl(struct btrfs_trans_handle *trans, 109 struct inode *inode, struct posix_acl *acl, int type) 110 { 111 int ret, size = 0; 112 const char *name; 113 char *value = NULL; 114 mode_t mode; 115 116 if (acl) { 117 ret = posix_acl_valid(acl); 118 if (ret < 0) 119 return ret; 120 ret = 0; 121 } 122 123 switch (type) { 124 case ACL_TYPE_ACCESS: 125 mode = inode->i_mode; 126 name = POSIX_ACL_XATTR_ACCESS; 127 if (acl) { 128 ret = posix_acl_equiv_mode(acl, &mode); 129 if (ret < 0) 130 return ret; 131 inode->i_mode = mode; 132 } 133 ret = 0; 134 break; 135 case ACL_TYPE_DEFAULT: 136 if (!S_ISDIR(inode->i_mode)) 137 return acl ? -EINVAL : 0; 138 name = POSIX_ACL_XATTR_DEFAULT; 139 break; 140 default: 141 return -EINVAL; 142 } 143 144 if (acl) { 145 size = posix_acl_xattr_size(acl->a_count); 146 value = kmalloc(size, GFP_NOFS); 147 if (!value) { 148 ret = -ENOMEM; 149 goto out; 150 } 151 152 ret = posix_acl_to_xattr(acl, value, size); 153 if (ret < 0) 154 goto out; 155 } 156 157 ret = __btrfs_setxattr(trans, inode, name, value, size, 0); 158 out: 159 kfree(value); 160 161 if (!ret) 162 set_cached_acl(inode, type, acl); 163 164 return ret; 165 } 166 167 static int btrfs_xattr_acl_set(struct dentry *dentry, const char *name, 168 const void *value, size_t size, int flags, int type) 169 { 170 int ret; 171 struct posix_acl *acl = NULL; 172 173 if (!is_owner_or_cap(dentry->d_inode)) 174 return -EPERM; 175 176 if (!IS_POSIXACL(dentry->d_inode)) 177 return -EOPNOTSUPP; 178 179 if (value) { 180 acl = posix_acl_from_xattr(value, size); 181 if (acl == NULL) { 182 value = NULL; 183 size = 0; 184 } else if (IS_ERR(acl)) { 185 return PTR_ERR(acl); 186 } 187 } 188 189 ret = btrfs_set_acl(NULL, dentry->d_inode, acl, type); 190 191 posix_acl_release(acl); 192 193 return ret; 194 } 195 196 int btrfs_check_acl(struct inode *inode, int mask, unsigned int flags) 197 { 198 int error = -EAGAIN; 199 200 if (flags & IPERM_FLAG_RCU) { 201 if (!negative_cached_acl(inode, ACL_TYPE_ACCESS)) 202 error = -ECHILD; 203 204 } else { 205 struct posix_acl *acl; 206 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); 207 if (IS_ERR(acl)) 208 return PTR_ERR(acl); 209 if (acl) { 210 error = posix_acl_permission(inode, acl, mask); 211 posix_acl_release(acl); 212 } 213 } 214 215 return error; 216 } 217 218 /* 219 * btrfs_init_acl is already generally called under fs_mutex, so the locking 220 * stuff has been fixed to work with that. If the locking stuff changes, we 221 * need to re-evaluate the acl locking stuff. 222 */ 223 int btrfs_init_acl(struct btrfs_trans_handle *trans, 224 struct inode *inode, struct inode *dir) 225 { 226 struct posix_acl *acl = NULL; 227 int ret = 0; 228 229 /* this happens with subvols */ 230 if (!dir) 231 return 0; 232 233 if (!S_ISLNK(inode->i_mode)) { 234 if (IS_POSIXACL(dir)) { 235 acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT); 236 if (IS_ERR(acl)) 237 return PTR_ERR(acl); 238 } 239 240 if (!acl) 241 inode->i_mode &= ~current_umask(); 242 } 243 244 if (IS_POSIXACL(dir) && acl) { 245 struct posix_acl *clone; 246 mode_t mode; 247 248 if (S_ISDIR(inode->i_mode)) { 249 ret = btrfs_set_acl(trans, inode, acl, 250 ACL_TYPE_DEFAULT); 251 if (ret) 252 goto failed; 253 } 254 clone = posix_acl_clone(acl, GFP_NOFS); 255 ret = -ENOMEM; 256 if (!clone) 257 goto failed; 258 259 mode = inode->i_mode; 260 ret = posix_acl_create_masq(clone, &mode); 261 if (ret >= 0) { 262 inode->i_mode = mode; 263 if (ret > 0) { 264 /* we need an acl */ 265 ret = btrfs_set_acl(trans, inode, clone, 266 ACL_TYPE_ACCESS); 267 } 268 } 269 posix_acl_release(clone); 270 } 271 failed: 272 posix_acl_release(acl); 273 274 return ret; 275 } 276 277 int btrfs_acl_chmod(struct inode *inode) 278 { 279 struct posix_acl *acl, *clone; 280 int ret = 0; 281 282 if (S_ISLNK(inode->i_mode)) 283 return -EOPNOTSUPP; 284 285 if (!IS_POSIXACL(inode)) 286 return 0; 287 288 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); 289 if (IS_ERR(acl) || !acl) 290 return PTR_ERR(acl); 291 292 clone = posix_acl_clone(acl, GFP_KERNEL); 293 posix_acl_release(acl); 294 if (!clone) 295 return -ENOMEM; 296 297 ret = posix_acl_chmod_masq(clone, inode->i_mode); 298 if (!ret) 299 ret = btrfs_set_acl(NULL, inode, clone, ACL_TYPE_ACCESS); 300 301 posix_acl_release(clone); 302 303 return ret; 304 } 305 306 const struct xattr_handler btrfs_xattr_acl_default_handler = { 307 .prefix = POSIX_ACL_XATTR_DEFAULT, 308 .flags = ACL_TYPE_DEFAULT, 309 .get = btrfs_xattr_acl_get, 310 .set = btrfs_xattr_acl_set, 311 }; 312 313 const struct xattr_handler btrfs_xattr_acl_access_handler = { 314 .prefix = POSIX_ACL_XATTR_ACCESS, 315 .flags = ACL_TYPE_ACCESS, 316 .get = btrfs_xattr_acl_get, 317 .set = btrfs_xattr_acl_set, 318 }; 319 320 #else /* CONFIG_BTRFS_FS_POSIX_ACL */ 321 322 int btrfs_acl_chmod(struct inode *inode) 323 { 324 return 0; 325 } 326 327 int btrfs_init_acl(struct btrfs_trans_handle *trans, 328 struct inode *inode, struct inode *dir) 329 { 330 return 0; 331 } 332 333 #endif /* CONFIG_BTRFS_FS_POSIX_ACL */ 334