| /* |
| * Copyright (C) 2007 Red Hat. All rights reserved. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public |
| * License v2 as published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public |
| * License along with this program; if not, write to the |
| * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| * Boston, MA 021110-1307, USA. |
| */ |
| |
| #include <linux/init.h> |
| #include <linux/fs.h> |
| #include <linux/slab.h> |
| #include <linux/rwsem.h> |
| #include <linux/xattr.h> |
| #include <linux/security.h> |
| #include "ctree.h" |
| #include "btrfs_inode.h" |
| #include "transaction.h" |
| #include "xattr.h" |
| #include "disk-io.h" |
| |
| |
| ssize_t __btrfs_getxattr(struct inode *inode, const char *name, |
| void *buffer, size_t size) |
| { |
| struct btrfs_dir_item *di; |
| struct btrfs_root *root = BTRFS_I(inode)->root; |
| struct btrfs_path *path; |
| struct extent_buffer *leaf; |
| int ret = 0; |
| unsigned long data_ptr; |
| |
| path = btrfs_alloc_path(); |
| if (!path) |
| return -ENOMEM; |
| |
| /* lookup the xattr by name */ |
| di = btrfs_lookup_xattr(NULL, root, path, inode->i_ino, name, |
| strlen(name), 0); |
| if (!di) { |
| ret = -ENODATA; |
| goto out; |
| } else if (IS_ERR(di)) { |
| ret = PTR_ERR(di); |
| goto out; |
| } |
| |
| leaf = path->nodes[0]; |
| /* if size is 0, that means we want the size of the attr */ |
| if (!size) { |
| ret = btrfs_dir_data_len(leaf, di); |
| goto out; |
| } |
| |
| /* now get the data out of our dir_item */ |
| if (btrfs_dir_data_len(leaf, di) > size) { |
| ret = -ERANGE; |
| goto out; |
| } |
| |
| /* |
| * The way things are packed into the leaf is like this |
| * |struct btrfs_dir_item|name|data| |
| * where name is the xattr name, so security.foo, and data is the |
| * content of the xattr. data_ptr points to the location in memory |
| * where the data starts in the in memory leaf |
| */ |
| data_ptr = (unsigned long)((char *)(di + 1) + |
| btrfs_dir_name_len(leaf, di)); |
| read_extent_buffer(leaf, buffer, data_ptr, |
| btrfs_dir_data_len(leaf, di)); |
| ret = btrfs_dir_data_len(leaf, di); |
| |
| out: |
| btrfs_free_path(path); |
| return ret; |
| } |
| |
| static int do_setxattr(struct btrfs_trans_handle *trans, |
| struct inode *inode, const char *name, |
| const void *value, size_t size, int flags) |
| { |
| struct btrfs_dir_item *di; |
| struct btrfs_root *root = BTRFS_I(inode)->root; |
| struct btrfs_path *path; |
| size_t name_len = strlen(name); |
| int ret = 0; |
| |
| if (name_len + size > BTRFS_MAX_XATTR_SIZE(root)) |
| return -ENOSPC; |
| |
| path = btrfs_alloc_path(); |
| if (!path) |
| return -ENOMEM; |
| |
| /* first lets see if we already have this xattr */ |
| di = btrfs_lookup_xattr(trans, root, path, inode->i_ino, name, |
| strlen(name), -1); |
| if (IS_ERR(di)) { |
| ret = PTR_ERR(di); |
| goto out; |
| } |
| |
| /* ok we already have this xattr, lets remove it */ |
| if (di) { |
| /* if we want create only exit */ |
| if (flags & XATTR_CREATE) { |
| ret = -EEXIST; |
| goto out; |
| } |
| |
| ret = btrfs_delete_one_dir_name(trans, root, path, di); |
| BUG_ON(ret); |
| btrfs_release_path(path); |
| |
| /* if we don't have a value then we are removing the xattr */ |
| if (!value) |
| goto out; |
| } else { |
| btrfs_release_path(path); |
| |
| if (flags & XATTR_REPLACE) { |
| /* we couldn't find the attr to replace */ |
| ret = -ENODATA; |
| goto out; |
| } |
| } |
| |
| /* ok we have to create a completely new xattr */ |
| ret = btrfs_insert_xattr_item(trans, root, path, inode->i_ino, |
| name, name_len, value, size); |
| BUG_ON(ret); |
| out: |
| btrfs_free_path(path); |
| return ret; |
| } |
| |
| int __btrfs_setxattr(struct btrfs_trans_handle *trans, |
| struct inode *inode, const char *name, |
| const void *value, size_t size, int flags) |
| { |
| struct btrfs_root *root = BTRFS_I(inode)->root; |
| int ret; |
| |
| if (trans) |
| return do_setxattr(trans, inode, name, value, size, flags); |
| |
| trans = btrfs_start_transaction(root, 2); |
| if (IS_ERR(trans)) |
| return PTR_ERR(trans); |
| |
| btrfs_set_trans_block_group(trans, inode); |
| |
| ret = do_setxattr(trans, inode, name, value, size, flags); |
| if (ret) |
| goto out; |
| |
| inode->i_ctime = CURRENT_TIME; |
| ret = btrfs_update_inode(trans, root, inode); |
| BUG_ON(ret); |
| out: |
| btrfs_end_transaction_throttle(trans, root); |
| return ret; |
| } |
| |
| ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size) |
| { |
| struct btrfs_key key, found_key; |
| struct inode *inode = dentry->d_inode; |
| struct btrfs_root *root = BTRFS_I(inode)->root; |
| struct btrfs_path *path; |
| struct extent_buffer *leaf; |
| struct btrfs_dir_item *di; |
| int ret = 0, slot; |
| size_t total_size = 0, size_left = size; |
| unsigned long name_ptr; |
| size_t name_len; |
| |
| /* |
| * ok we want all objects associated with this id. |
| * NOTE: we set key.offset = 0; because we want to start with the |
| * first xattr that we find and walk forward |
| */ |
| key.objectid = inode->i_ino; |
| btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY); |
| key.offset = 0; |
| |
| path = btrfs_alloc_path(); |
| if (!path) |
| return -ENOMEM; |
| path->reada = 2; |
| |
| /* search for our xattrs */ |
| ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); |
| if (ret < 0) |
| goto err; |
| |
| while (1) { |
| leaf = path->nodes[0]; |
| slot = path->slots[0]; |
| |
| /* this is where we start walking through the path */ |
| if (slot >= btrfs_header_nritems(leaf)) { |
| /* |
| * if we've reached the last slot in this leaf we need |
| * to go to the next leaf and reset everything |
| */ |
| ret = btrfs_next_leaf(root, path); |
| if (ret < 0) |
| goto err; |
| else if (ret > 0) |
| break; |
| continue; |
| } |
| |
| btrfs_item_key_to_cpu(leaf, &found_key, slot); |
| |
| /* check to make sure this item is what we want */ |
| if (found_key.objectid != key.objectid) |
| break; |
| if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY) |
| break; |
| |
| di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); |
| if (verify_dir_item(root, leaf, di)) |
| continue; |
| |
| name_len = btrfs_dir_name_len(leaf, di); |
| total_size += name_len + 1; |
| |
| /* we are just looking for how big our buffer needs to be */ |
| if (!size) |
| goto next; |
| |
| if (!buffer || (name_len + 1) > size_left) { |
| ret = -ERANGE; |
| goto err; |
| } |
| |
| name_ptr = (unsigned long)(di + 1); |
| read_extent_buffer(leaf, buffer, name_ptr, name_len); |
| buffer[name_len] = '\0'; |
| |
| size_left -= name_len + 1; |
| buffer += name_len + 1; |
| next: |
| path->slots[0]++; |
| } |
| ret = total_size; |
| |
| err: |
| btrfs_free_path(path); |
| |
| return ret; |
| } |
| |
| /* |
| * List of handlers for synthetic system.* attributes. All real ondisk |
| * attributes are handled directly. |
| */ |
| const struct xattr_handler *btrfs_xattr_handlers[] = { |
| #ifdef CONFIG_BTRFS_FS_POSIX_ACL |
| &btrfs_xattr_acl_access_handler, |
| &btrfs_xattr_acl_default_handler, |
| #endif |
| NULL, |
| }; |
| |
| /* |
| * Check if the attribute is in a supported namespace. |
| * |
| * This applied after the check for the synthetic attributes in the system |
| * namespace. |
| */ |
| static bool btrfs_is_valid_xattr(const char *name) |
| { |
| return !strncmp(name, XATTR_SECURITY_PREFIX, |
| XATTR_SECURITY_PREFIX_LEN) || |
| !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) || |
| !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) || |
| !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN); |
| } |
| |
| ssize_t btrfs_getxattr(struct dentry *dentry, const char *name, |
| void *buffer, size_t size) |
| { |
| /* |
| * If this is a request for a synthetic attribute in the system.* |
| * namespace use the generic infrastructure to resolve a handler |
| * for it via sb->s_xattr. |
| */ |
| if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) |
| return generic_getxattr(dentry, name, buffer, size); |
| |
| if (!btrfs_is_valid_xattr(name)) |
| return -EOPNOTSUPP; |
| return __btrfs_getxattr(dentry->d_inode, name, buffer, size); |
| } |
| |
| int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value, |
| size_t size, int flags) |
| { |
| struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root; |
| |
| /* |
| * The permission on security.* and system.* is not checked |
| * in permission(). |
| */ |
| if (btrfs_root_readonly(root)) |
| return -EROFS; |
| |
| /* |
| * If this is a request for a synthetic attribute in the system.* |
| * namespace use the generic infrastructure to resolve a handler |
| * for it via sb->s_xattr. |
| */ |
| if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) |
| return generic_setxattr(dentry, name, value, size, flags); |
| |
| if (!btrfs_is_valid_xattr(name)) |
| return -EOPNOTSUPP; |
| |
| if (size == 0) |
| value = ""; /* empty EA, do not remove */ |
| |
| return __btrfs_setxattr(NULL, dentry->d_inode, name, value, size, |
| flags); |
| } |
| |
| int btrfs_removexattr(struct dentry *dentry, const char *name) |
| { |
| struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root; |
| |
| /* |
| * The permission on security.* and system.* is not checked |
| * in permission(). |
| */ |
| if (btrfs_root_readonly(root)) |
| return -EROFS; |
| |
| /* |
| * If this is a request for a synthetic attribute in the system.* |
| * namespace use the generic infrastructure to resolve a handler |
| * for it via sb->s_xattr. |
| */ |
| if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) |
| return generic_removexattr(dentry, name); |
| |
| if (!btrfs_is_valid_xattr(name)) |
| return -EOPNOTSUPP; |
| |
| return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0, |
| XATTR_REPLACE); |
| } |
| |
| int btrfs_xattr_security_init(struct btrfs_trans_handle *trans, |
| struct inode *inode, struct inode *dir, |
| const struct qstr *qstr) |
| { |
| int err; |
| size_t len; |
| void *value; |
| char *suffix; |
| char *name; |
| |
| err = security_inode_init_security(inode, dir, qstr, &suffix, &value, |
| &len); |
| if (err) { |
| if (err == -EOPNOTSUPP) |
| return 0; |
| return err; |
| } |
| |
| name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(suffix) + 1, |
| GFP_NOFS); |
| if (!name) { |
| err = -ENOMEM; |
| } else { |
| strcpy(name, XATTR_SECURITY_PREFIX); |
| strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix); |
| err = __btrfs_setxattr(trans, inode, name, value, len, 0); |
| kfree(name); |
| } |
| |
| kfree(suffix); |
| kfree(value); |
| return err; |
| } |