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![Gabriel Niebler](/assets/img/avatar_default.png)
This function can be simplified by refactoring to use the new iterator macro. No functional changes. Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com> Signed-off-by: Gabriel Niebler <gniebler@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
489 lines
13 KiB
C
489 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2007 Red Hat. All rights reserved.
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*/
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include <linux/rwsem.h>
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#include <linux/xattr.h>
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#include <linux/security.h>
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#include <linux/posix_acl_xattr.h>
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#include <linux/iversion.h>
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#include <linux/sched/mm.h>
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#include "ctree.h"
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#include "btrfs_inode.h"
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#include "transaction.h"
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#include "xattr.h"
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#include "disk-io.h"
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#include "props.h"
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#include "locking.h"
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int btrfs_getxattr(struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct btrfs_dir_item *di;
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struct btrfs_root *root = BTRFS_I(inode)->root;
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struct btrfs_path *path;
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struct extent_buffer *leaf;
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int ret = 0;
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unsigned long data_ptr;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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/* lookup the xattr by name */
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di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)),
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name, strlen(name), 0);
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if (!di) {
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ret = -ENODATA;
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goto out;
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} else if (IS_ERR(di)) {
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ret = PTR_ERR(di);
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goto out;
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}
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leaf = path->nodes[0];
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/* if size is 0, that means we want the size of the attr */
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if (!size) {
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ret = btrfs_dir_data_len(leaf, di);
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goto out;
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}
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/* now get the data out of our dir_item */
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if (btrfs_dir_data_len(leaf, di) > size) {
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ret = -ERANGE;
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goto out;
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}
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/*
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* The way things are packed into the leaf is like this
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* |struct btrfs_dir_item|name|data|
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* where name is the xattr name, so security.foo, and data is the
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* content of the xattr. data_ptr points to the location in memory
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* where the data starts in the in memory leaf
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*/
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data_ptr = (unsigned long)((char *)(di + 1) +
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btrfs_dir_name_len(leaf, di));
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read_extent_buffer(leaf, buffer, data_ptr,
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btrfs_dir_data_len(leaf, di));
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ret = btrfs_dir_data_len(leaf, di);
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out:
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btrfs_free_path(path);
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return ret;
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}
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int btrfs_setxattr(struct btrfs_trans_handle *trans, struct inode *inode,
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const char *name, const void *value, size_t size, int flags)
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{
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struct btrfs_dir_item *di = NULL;
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struct btrfs_root *root = BTRFS_I(inode)->root;
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struct btrfs_fs_info *fs_info = root->fs_info;
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struct btrfs_path *path;
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size_t name_len = strlen(name);
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int ret = 0;
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ASSERT(trans);
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if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info))
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return -ENOSPC;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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path->skip_release_on_error = 1;
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if (!value) {
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di = btrfs_lookup_xattr(trans, root, path,
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btrfs_ino(BTRFS_I(inode)), name, name_len, -1);
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if (!di && (flags & XATTR_REPLACE))
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ret = -ENODATA;
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else if (IS_ERR(di))
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ret = PTR_ERR(di);
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else if (di)
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ret = btrfs_delete_one_dir_name(trans, root, path, di);
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goto out;
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}
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/*
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* For a replace we can't just do the insert blindly.
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* Do a lookup first (read-only btrfs_search_slot), and return if xattr
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* doesn't exist. If it exists, fall down below to the insert/replace
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* path - we can't race with a concurrent xattr delete, because the VFS
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* locks the inode's i_mutex before calling setxattr or removexattr.
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*/
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if (flags & XATTR_REPLACE) {
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ASSERT(inode_is_locked(inode));
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di = btrfs_lookup_xattr(NULL, root, path,
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btrfs_ino(BTRFS_I(inode)), name, name_len, 0);
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if (!di)
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ret = -ENODATA;
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else if (IS_ERR(di))
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ret = PTR_ERR(di);
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if (ret)
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goto out;
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btrfs_release_path(path);
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di = NULL;
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}
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ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)),
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name, name_len, value, size);
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if (ret == -EOVERFLOW) {
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/*
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* We have an existing item in a leaf, split_leaf couldn't
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* expand it. That item might have or not a dir_item that
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* matches our target xattr, so lets check.
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*/
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ret = 0;
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btrfs_assert_tree_write_locked(path->nodes[0]);
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di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
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if (!di && !(flags & XATTR_REPLACE)) {
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ret = -ENOSPC;
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goto out;
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}
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} else if (ret == -EEXIST) {
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ret = 0;
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di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
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ASSERT(di); /* logic error */
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} else if (ret) {
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goto out;
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}
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if (di && (flags & XATTR_CREATE)) {
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ret = -EEXIST;
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goto out;
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}
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if (di) {
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/*
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* We're doing a replace, and it must be atomic, that is, at
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* any point in time we have either the old or the new xattr
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* value in the tree. We don't want readers (getxattr and
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* listxattrs) to miss a value, this is specially important
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* for ACLs.
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*/
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const int slot = path->slots[0];
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struct extent_buffer *leaf = path->nodes[0];
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const u16 old_data_len = btrfs_dir_data_len(leaf, di);
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const u32 item_size = btrfs_item_size(leaf, slot);
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const u32 data_size = sizeof(*di) + name_len + size;
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unsigned long data_ptr;
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char *ptr;
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if (size > old_data_len) {
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if (btrfs_leaf_free_space(leaf) <
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(size - old_data_len)) {
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ret = -ENOSPC;
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goto out;
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}
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}
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if (old_data_len + name_len + sizeof(*di) == item_size) {
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/* No other xattrs packed in the same leaf item. */
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if (size > old_data_len)
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btrfs_extend_item(path, size - old_data_len);
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else if (size < old_data_len)
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btrfs_truncate_item(path, data_size, 1);
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} else {
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/* There are other xattrs packed in the same item. */
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ret = btrfs_delete_one_dir_name(trans, root, path, di);
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if (ret)
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goto out;
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btrfs_extend_item(path, data_size);
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}
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ptr = btrfs_item_ptr(leaf, slot, char);
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ptr += btrfs_item_size(leaf, slot) - data_size;
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di = (struct btrfs_dir_item *)ptr;
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btrfs_set_dir_data_len(leaf, di, size);
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data_ptr = ((unsigned long)(di + 1)) + name_len;
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write_extent_buffer(leaf, value, data_ptr, size);
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btrfs_mark_buffer_dirty(leaf);
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} else {
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/*
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* Insert, and we had space for the xattr, so path->slots[0] is
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* where our xattr dir_item is and btrfs_insert_xattr_item()
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* filled it.
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*/
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}
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out:
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btrfs_free_path(path);
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if (!ret) {
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set_bit(BTRFS_INODE_COPY_EVERYTHING,
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&BTRFS_I(inode)->runtime_flags);
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clear_bit(BTRFS_INODE_NO_XATTRS, &BTRFS_I(inode)->runtime_flags);
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}
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return ret;
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}
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/*
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* @value: "" makes the attribute to empty, NULL removes it
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*/
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int btrfs_setxattr_trans(struct inode *inode, const char *name,
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const void *value, size_t size, int flags)
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{
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struct btrfs_root *root = BTRFS_I(inode)->root;
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struct btrfs_trans_handle *trans;
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const bool start_trans = (current->journal_info == NULL);
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int ret;
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if (start_trans) {
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/*
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* 1 unit for inserting/updating/deleting the xattr
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* 1 unit for the inode item update
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*/
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trans = btrfs_start_transaction(root, 2);
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if (IS_ERR(trans))
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return PTR_ERR(trans);
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} else {
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/*
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* This can happen when smack is enabled and a directory is being
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* created. It happens through d_instantiate_new(), which calls
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* smack_d_instantiate(), which in turn calls __vfs_setxattr() to
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* set the transmute xattr (XATTR_NAME_SMACKTRANSMUTE) on the
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* inode. We have already reserved space for the xattr and inode
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* update at btrfs_mkdir(), so just use the transaction handle.
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* We don't join or start a transaction, as that will reset the
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* block_rsv of the handle and trigger a warning for the start
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* case.
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*/
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ASSERT(strncmp(name, XATTR_SECURITY_PREFIX,
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XATTR_SECURITY_PREFIX_LEN) == 0);
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trans = current->journal_info;
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}
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ret = btrfs_setxattr(trans, inode, name, value, size, flags);
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if (ret)
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goto out;
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inode_inc_iversion(inode);
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inode->i_ctime = current_time(inode);
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ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
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if (ret)
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btrfs_abort_transaction(trans, ret);
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out:
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if (start_trans)
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btrfs_end_transaction(trans);
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return ret;
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}
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ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
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{
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struct btrfs_key found_key;
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struct btrfs_key key;
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struct inode *inode = d_inode(dentry);
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struct btrfs_root *root = BTRFS_I(inode)->root;
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struct btrfs_path *path;
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int iter_ret = 0;
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int ret = 0;
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size_t total_size = 0, size_left = size;
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/*
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* ok we want all objects associated with this id.
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* NOTE: we set key.offset = 0; because we want to start with the
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* first xattr that we find and walk forward
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*/
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key.objectid = btrfs_ino(BTRFS_I(inode));
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key.type = BTRFS_XATTR_ITEM_KEY;
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key.offset = 0;
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path = btrfs_alloc_path();
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if (!path)
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return -ENOMEM;
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path->reada = READA_FORWARD;
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/* search for our xattrs */
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btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) {
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struct extent_buffer *leaf;
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int slot;
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struct btrfs_dir_item *di;
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u32 item_size;
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u32 cur;
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leaf = path->nodes[0];
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slot = path->slots[0];
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/* check to make sure this item is what we want */
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if (found_key.objectid != key.objectid)
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break;
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if (found_key.type > BTRFS_XATTR_ITEM_KEY)
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break;
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if (found_key.type < BTRFS_XATTR_ITEM_KEY)
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continue;
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di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
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item_size = btrfs_item_size(leaf, slot);
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cur = 0;
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while (cur < item_size) {
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u16 name_len = btrfs_dir_name_len(leaf, di);
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u16 data_len = btrfs_dir_data_len(leaf, di);
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u32 this_len = sizeof(*di) + name_len + data_len;
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unsigned long name_ptr = (unsigned long)(di + 1);
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total_size += name_len + 1;
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/*
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* We are just looking for how big our buffer needs to
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* be.
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*/
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if (!size)
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goto next;
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if (!buffer || (name_len + 1) > size_left) {
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iter_ret = -ERANGE;
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break;
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}
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read_extent_buffer(leaf, buffer, name_ptr, name_len);
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buffer[name_len] = '\0';
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size_left -= name_len + 1;
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buffer += name_len + 1;
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next:
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cur += this_len;
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di = (struct btrfs_dir_item *)((char *)di + this_len);
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}
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}
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if (iter_ret < 0)
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ret = iter_ret;
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else
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ret = total_size;
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btrfs_free_path(path);
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return ret;
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}
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static int btrfs_xattr_handler_get(const struct xattr_handler *handler,
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struct dentry *unused, struct inode *inode,
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const char *name, void *buffer, size_t size)
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{
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name = xattr_full_name(handler, name);
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return btrfs_getxattr(inode, name, buffer, size);
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}
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static int btrfs_xattr_handler_set(const struct xattr_handler *handler,
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struct user_namespace *mnt_userns,
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struct dentry *unused, struct inode *inode,
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const char *name, const void *buffer,
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size_t size, int flags)
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{
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name = xattr_full_name(handler, name);
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return btrfs_setxattr_trans(inode, name, buffer, size, flags);
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}
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static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler,
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struct user_namespace *mnt_userns,
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struct dentry *unused, struct inode *inode,
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const char *name, const void *value,
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size_t size, int flags)
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{
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int ret;
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struct btrfs_trans_handle *trans;
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struct btrfs_root *root = BTRFS_I(inode)->root;
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name = xattr_full_name(handler, name);
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ret = btrfs_validate_prop(BTRFS_I(inode), name, value, size);
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if (ret)
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return ret;
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if (btrfs_ignore_prop(BTRFS_I(inode), name))
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return 0;
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trans = btrfs_start_transaction(root, 2);
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if (IS_ERR(trans))
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return PTR_ERR(trans);
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ret = btrfs_set_prop(trans, inode, name, value, size, flags);
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if (!ret) {
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inode_inc_iversion(inode);
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inode->i_ctime = current_time(inode);
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ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
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if (ret)
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btrfs_abort_transaction(trans, ret);
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}
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btrfs_end_transaction(trans);
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return ret;
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}
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static const struct xattr_handler btrfs_security_xattr_handler = {
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.prefix = XATTR_SECURITY_PREFIX,
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.get = btrfs_xattr_handler_get,
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.set = btrfs_xattr_handler_set,
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};
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static const struct xattr_handler btrfs_trusted_xattr_handler = {
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.prefix = XATTR_TRUSTED_PREFIX,
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.get = btrfs_xattr_handler_get,
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.set = btrfs_xattr_handler_set,
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};
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static const struct xattr_handler btrfs_user_xattr_handler = {
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.prefix = XATTR_USER_PREFIX,
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.get = btrfs_xattr_handler_get,
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.set = btrfs_xattr_handler_set,
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};
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static const struct xattr_handler btrfs_btrfs_xattr_handler = {
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.prefix = XATTR_BTRFS_PREFIX,
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.get = btrfs_xattr_handler_get,
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.set = btrfs_xattr_handler_set_prop,
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};
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const struct xattr_handler *btrfs_xattr_handlers[] = {
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&btrfs_security_xattr_handler,
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#ifdef CONFIG_BTRFS_FS_POSIX_ACL
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&posix_acl_access_xattr_handler,
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&posix_acl_default_xattr_handler,
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#endif
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&btrfs_trusted_xattr_handler,
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&btrfs_user_xattr_handler,
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&btrfs_btrfs_xattr_handler,
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NULL,
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};
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static int btrfs_initxattrs(struct inode *inode,
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const struct xattr *xattr_array, void *fs_private)
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{
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struct btrfs_trans_handle *trans = fs_private;
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const struct xattr *xattr;
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unsigned int nofs_flag;
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char *name;
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int err = 0;
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/*
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* We're holding a transaction handle, so use a NOFS memory allocation
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* context to avoid deadlock if reclaim happens.
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*/
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nofs_flag = memalloc_nofs_save();
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for (xattr = xattr_array; xattr->name != NULL; xattr++) {
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name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
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strlen(xattr->name) + 1, GFP_KERNEL);
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if (!name) {
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err = -ENOMEM;
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break;
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}
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strcpy(name, XATTR_SECURITY_PREFIX);
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strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
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err = btrfs_setxattr(trans, inode, name, xattr->value,
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xattr->value_len, 0);
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kfree(name);
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if (err < 0)
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break;
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}
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memalloc_nofs_restore(nofs_flag);
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return err;
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}
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|
int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
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struct inode *inode, struct inode *dir,
|
|
const struct qstr *qstr)
|
|
{
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return security_inode_init_security(inode, dir, qstr,
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&btrfs_initxattrs, trans);
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|
}
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