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 acl = get_cached_acl(inode, type); 41 if (acl != ACL_NOT_CACHED) 42 return acl; 43 44 switch (type) { 45 case ACL_TYPE_ACCESS: 46 name = POSIX_ACL_XATTR_ACCESS; 47 break; 48 case ACL_TYPE_DEFAULT: 49 name = POSIX_ACL_XATTR_DEFAULT; 50 break; 51 default: 52 BUG(); 53 } 54 55 size = __btrfs_getxattr(inode, name, "", 0); 56 if (size > 0) { 57 value = kzalloc(size, GFP_NOFS); 58 if (!value) 59 return ERR_PTR(-ENOMEM); 60 size = __btrfs_getxattr(inode, name, value, size); 61 if (size > 0) { 62 acl = posix_acl_from_xattr(value, size); 63 if (IS_ERR(acl)) { 64 kfree(value); 65 return acl; 66 } 67 set_cached_acl(inode, type, acl); 68 } 69 kfree(value); 70 } else if (size == -ENOENT || size == -ENODATA || size == 0) { 71 /* FIXME, who returns -ENOENT? I think nobody */ 72 acl = NULL; 73 set_cached_acl(inode, type, acl); 74 } else { 75 acl = ERR_PTR(-EIO); 76 } 77 78 return acl; 79 } 80 81 static int btrfs_xattr_acl_get(struct dentry *dentry, const char *name, 82 void *value, size_t size, int type) 83 { 84 struct posix_acl *acl; 85 int ret = 0; 86 87 acl = btrfs_get_acl(dentry->d_inode, type); 88 89 if (IS_ERR(acl)) 90 return PTR_ERR(acl); 91 if (acl == NULL) 92 return -ENODATA; 93 ret = posix_acl_to_xattr(acl, value, size); 94 posix_acl_release(acl); 95 96 return ret; 97 } 98 99 /* 100 * Needs to be called with fs_mutex held 101 */ 102 static int btrfs_set_acl(struct btrfs_trans_handle *trans, 103 struct inode *inode, struct posix_acl *acl, int type) 104 { 105 int ret, size = 0; 106 const char *name; 107 char *value = NULL; 108 mode_t mode; 109 110 if (acl) { 111 ret = posix_acl_valid(acl); 112 if (ret < 0) 113 return ret; 114 ret = 0; 115 } 116 117 switch (type) { 118 case ACL_TYPE_ACCESS: 119 mode = inode->i_mode; 120 name = POSIX_ACL_XATTR_ACCESS; 121 if (acl) { 122 ret = posix_acl_equiv_mode(acl, &mode); 123 if (ret < 0) 124 return ret; 125 inode->i_mode = mode; 126 } 127 ret = 0; 128 break; 129 case ACL_TYPE_DEFAULT: 130 if (!S_ISDIR(inode->i_mode)) 131 return acl ? -EINVAL : 0; 132 name = POSIX_ACL_XATTR_DEFAULT; 133 break; 134 default: 135 return -EINVAL; 136 } 137 138 if (acl) { 139 size = posix_acl_xattr_size(acl->a_count); 140 value = kmalloc(size, GFP_NOFS); 141 if (!value) { 142 ret = -ENOMEM; 143 goto out; 144 } 145 146 ret = posix_acl_to_xattr(acl, value, size); 147 if (ret < 0) 148 goto out; 149 } 150 151 ret = __btrfs_setxattr(trans, inode, name, value, size, 0); 152 out: 153 kfree(value); 154 155 if (!ret) 156 set_cached_acl(inode, type, acl); 157 158 return ret; 159 } 160 161 static int btrfs_xattr_acl_set(struct dentry *dentry, const char *name, 162 const void *value, size_t size, int flags, int type) 163 { 164 int ret; 165 struct posix_acl *acl = NULL; 166 167 if (!is_owner_or_cap(dentry->d_inode)) 168 return -EPERM; 169 170 if (!IS_POSIXACL(dentry->d_inode)) 171 return -EOPNOTSUPP; 172 173 if (value) { 174 acl = posix_acl_from_xattr(value, size); 175 if (acl == NULL) { 176 value = NULL; 177 size = 0; 178 } else if (IS_ERR(acl)) { 179 return PTR_ERR(acl); 180 } 181 } 182 183 ret = btrfs_set_acl(NULL, dentry->d_inode, acl, type); 184 185 posix_acl_release(acl); 186 187 return ret; 188 } 189 190 int btrfs_check_acl(struct inode *inode, int mask, unsigned int flags) 191 { 192 int error = -EAGAIN; 193 194 if (flags & IPERM_FLAG_RCU) { 195 if (!negative_cached_acl(inode, ACL_TYPE_ACCESS)) 196 error = -ECHILD; 197 198 } else { 199 struct posix_acl *acl; 200 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); 201 if (IS_ERR(acl)) 202 return PTR_ERR(acl); 203 if (acl) { 204 error = posix_acl_permission(inode, acl, mask); 205 posix_acl_release(acl); 206 } 207 } 208 209 return error; 210 } 211 212 /* 213 * btrfs_init_acl is already generally called under fs_mutex, so the locking 214 * stuff has been fixed to work with that. If the locking stuff changes, we 215 * need to re-evaluate the acl locking stuff. 216 */ 217 int btrfs_init_acl(struct btrfs_trans_handle *trans, 218 struct inode *inode, struct inode *dir) 219 { 220 struct posix_acl *acl = NULL; 221 int ret = 0; 222 223 /* this happens with subvols */ 224 if (!dir) 225 return 0; 226 227 if (!S_ISLNK(inode->i_mode)) { 228 if (IS_POSIXACL(dir)) { 229 acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT); 230 if (IS_ERR(acl)) 231 return PTR_ERR(acl); 232 } 233 234 if (!acl) 235 inode->i_mode &= ~current_umask(); 236 } 237 238 if (IS_POSIXACL(dir) && acl) { 239 struct posix_acl *clone; 240 mode_t mode; 241 242 if (S_ISDIR(inode->i_mode)) { 243 ret = btrfs_set_acl(trans, inode, acl, 244 ACL_TYPE_DEFAULT); 245 if (ret) 246 goto failed; 247 } 248 clone = posix_acl_clone(acl, GFP_NOFS); 249 ret = -ENOMEM; 250 if (!clone) 251 goto failed; 252 253 mode = inode->i_mode; 254 ret = posix_acl_create_masq(clone, &mode); 255 if (ret >= 0) { 256 inode->i_mode = mode; 257 if (ret > 0) { 258 /* we need an acl */ 259 ret = btrfs_set_acl(trans, inode, clone, 260 ACL_TYPE_ACCESS); 261 } 262 } 263 posix_acl_release(clone); 264 } 265 failed: 266 posix_acl_release(acl); 267 268 return ret; 269 } 270 271 int btrfs_acl_chmod(struct inode *inode) 272 { 273 struct posix_acl *acl, *clone; 274 int ret = 0; 275 276 if (S_ISLNK(inode->i_mode)) 277 return -EOPNOTSUPP; 278 279 if (!IS_POSIXACL(inode)) 280 return 0; 281 282 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); 283 if (IS_ERR(acl) || !acl) 284 return PTR_ERR(acl); 285 286 clone = posix_acl_clone(acl, GFP_KERNEL); 287 posix_acl_release(acl); 288 if (!clone) 289 return -ENOMEM; 290 291 ret = posix_acl_chmod_masq(clone, inode->i_mode); 292 if (!ret) 293 ret = btrfs_set_acl(NULL, inode, clone, ACL_TYPE_ACCESS); 294 295 posix_acl_release(clone); 296 297 return ret; 298 } 299 300 const struct xattr_handler btrfs_xattr_acl_default_handler = { 301 .prefix = POSIX_ACL_XATTR_DEFAULT, 302 .flags = ACL_TYPE_DEFAULT, 303 .get = btrfs_xattr_acl_get, 304 .set = btrfs_xattr_acl_set, 305 }; 306 307 const struct xattr_handler btrfs_xattr_acl_access_handler = { 308 .prefix = POSIX_ACL_XATTR_ACCESS, 309 .flags = ACL_TYPE_ACCESS, 310 .get = btrfs_xattr_acl_get, 311 .set = btrfs_xattr_acl_set, 312 }; 313 314 #else /* CONFIG_BTRFS_FS_POSIX_ACL */ 315 316 int btrfs_acl_chmod(struct inode *inode) 317 { 318 return 0; 319 } 320 321 int btrfs_init_acl(struct btrfs_trans_handle *trans, 322 struct inode *inode, struct inode *dir) 323 { 324 return 0; 325 } 326 327 #endif /* CONFIG_BTRFS_FS_POSIX_ACL */ 328