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