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 (!inode_owner_or_capable(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 (IS_ERR(acl)) 182 return PTR_ERR(acl); 183 184 if (acl) { 185 ret = posix_acl_valid(acl); 186 if (ret) 187 goto out; 188 } 189 } 190 191 ret = btrfs_set_acl(NULL, dentry->d_inode, acl, type); 192 out: 193 posix_acl_release(acl); 194 195 return ret; 196 } 197 198 int btrfs_check_acl(struct inode *inode, int mask) 199 { 200 int error = -EAGAIN; 201 202 if (mask & MAY_NOT_BLOCK) { 203 if (!negative_cached_acl(inode, ACL_TYPE_ACCESS)) 204 error = -ECHILD; 205 } else { 206 struct posix_acl *acl; 207 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); 208 if (IS_ERR(acl)) 209 return PTR_ERR(acl); 210 if (acl) { 211 error = posix_acl_permission(inode, acl, mask); 212 posix_acl_release(acl); 213 } 214 } 215 216 return error; 217 } 218 219 /* 220 * btrfs_init_acl is already generally called under fs_mutex, so the locking 221 * stuff has been fixed to work with that. If the locking stuff changes, we 222 * need to re-evaluate the acl locking stuff. 223 */ 224 int btrfs_init_acl(struct btrfs_trans_handle *trans, 225 struct inode *inode, struct inode *dir) 226 { 227 struct posix_acl *acl = NULL; 228 int ret = 0; 229 230 /* this happens with subvols */ 231 if (!dir) 232 return 0; 233 234 if (!S_ISLNK(inode->i_mode)) { 235 if (IS_POSIXACL(dir)) { 236 acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT); 237 if (IS_ERR(acl)) 238 return PTR_ERR(acl); 239 } 240 241 if (!acl) 242 inode->i_mode &= ~current_umask(); 243 } 244 245 if (IS_POSIXACL(dir) && acl) { 246 struct posix_acl *clone; 247 mode_t mode; 248 249 if (S_ISDIR(inode->i_mode)) { 250 ret = btrfs_set_acl(trans, inode, acl, 251 ACL_TYPE_DEFAULT); 252 if (ret) 253 goto failed; 254 } 255 clone = posix_acl_clone(acl, GFP_NOFS); 256 ret = -ENOMEM; 257 if (!clone) 258 goto failed; 259 260 mode = inode->i_mode; 261 ret = posix_acl_create_masq(clone, &mode); 262 if (ret >= 0) { 263 inode->i_mode = mode; 264 if (ret > 0) { 265 /* we need an acl */ 266 ret = btrfs_set_acl(trans, inode, clone, 267 ACL_TYPE_ACCESS); 268 } 269 } 270 posix_acl_release(clone); 271 } 272 failed: 273 posix_acl_release(acl); 274 275 return ret; 276 } 277 278 int btrfs_acl_chmod(struct inode *inode) 279 { 280 struct posix_acl *acl, *clone; 281 int ret = 0; 282 283 if (S_ISLNK(inode->i_mode)) 284 return -EOPNOTSUPP; 285 286 if (!IS_POSIXACL(inode)) 287 return 0; 288 289 acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS); 290 if (IS_ERR_OR_NULL(acl)) 291 return PTR_ERR(acl); 292 293 clone = posix_acl_clone(acl, GFP_KERNEL); 294 posix_acl_release(acl); 295 if (!clone) 296 return -ENOMEM; 297 298 ret = posix_acl_chmod_masq(clone, inode->i_mode); 299 if (!ret) 300 ret = btrfs_set_acl(NULL, inode, clone, ACL_TYPE_ACCESS); 301 302 posix_acl_release(clone); 303 304 return ret; 305 } 306 307 const struct xattr_handler btrfs_xattr_acl_default_handler = { 308 .prefix = POSIX_ACL_XATTR_DEFAULT, 309 .flags = ACL_TYPE_DEFAULT, 310 .get = btrfs_xattr_acl_get, 311 .set = btrfs_xattr_acl_set, 312 }; 313 314 const struct xattr_handler btrfs_xattr_acl_access_handler = { 315 .prefix = POSIX_ACL_XATTR_ACCESS, 316 .flags = ACL_TYPE_ACCESS, 317 .get = btrfs_xattr_acl_get, 318 .set = btrfs_xattr_acl_set, 319 }; 320 321 #else /* CONFIG_BTRFS_FS_POSIX_ACL */ 322 323 int btrfs_acl_chmod(struct inode *inode) 324 { 325 return 0; 326 } 327 328 int btrfs_init_acl(struct btrfs_trans_handle *trans, 329 struct inode *inode, struct inode *dir) 330 { 331 return 0; 332 } 333 334 #endif /* CONFIG_BTRFS_FS_POSIX_ACL */ 335