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