/* * 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 <linux/posix_acl_xattr.h> #include "ctree.h" #include "btrfs_inode.h" #include "transaction.h" #include "xattr.h" #include "disk-io.h" #include "props.h" #include "locking.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, btrfs_ino(BTRFS_I(inode)), 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 = NULL; struct btrfs_root *root = BTRFS_I(inode)->root; struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_path *path; size_t name_len = strlen(name); int ret = 0; if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info)) return -ENOSPC; path = btrfs_alloc_path(); if (!path) return -ENOMEM; path->skip_release_on_error = 1; if (!value) { di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(BTRFS_I(inode)), name, name_len, -1); if (!di && (flags & XATTR_REPLACE)) ret = -ENODATA; else if (IS_ERR(di)) ret = PTR_ERR(di); else if (di) ret = btrfs_delete_one_dir_name(trans, root, path, di); goto out; } /* * For a replace we can't just do the insert blindly. * Do a lookup first (read-only btrfs_search_slot), and return if xattr * doesn't exist. If it exists, fall down below to the insert/replace * path - we can't race with a concurrent xattr delete, because the VFS * locks the inode's i_mutex before calling setxattr or removexattr. */ if (flags & XATTR_REPLACE) { ASSERT(inode_is_locked(inode)); di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)), name, name_len, 0); if (!di) ret = -ENODATA; else if (IS_ERR(di)) ret = PTR_ERR(di); if (ret) goto out; btrfs_release_path(path); di = NULL; } ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)), name, name_len, value, size); if (ret == -EOVERFLOW) { /* * We have an existing item in a leaf, split_leaf couldn't * expand it. That item might have or not a dir_item that * matches our target xattr, so lets check. */ ret = 0; btrfs_assert_tree_locked(path->nodes[0]); di = btrfs_match_dir_item_name(fs_info, path, name, name_len); if (!di && !(flags & XATTR_REPLACE)) { ret = -ENOSPC; goto out; } } else if (ret == -EEXIST) { ret = 0; di = btrfs_match_dir_item_name(fs_info, path, name, name_len); ASSERT(di); /* logic error */ } else if (ret) { goto out; } if (di && (flags & XATTR_CREATE)) { ret = -EEXIST; goto out; } if (di) { /* * We're doing a replace, and it must be atomic, that is, at * any point in time we have either the old or the new xattr * value in the tree. We don't want readers (getxattr and * listxattrs) to miss a value, this is specially important * for ACLs. */ const int slot = path->slots[0]; struct extent_buffer *leaf = path->nodes[0]; const u16 old_data_len = btrfs_dir_data_len(leaf, di); const u32 item_size = btrfs_item_size_nr(leaf, slot); const u32 data_size = sizeof(*di) + name_len + size; struct btrfs_item *item; unsigned long data_ptr; char *ptr; if (size > old_data_len) { if (btrfs_leaf_free_space(fs_info, leaf) < (size - old_data_len)) { ret = -ENOSPC; goto out; } } if (old_data_len + name_len + sizeof(*di) == item_size) { /* No other xattrs packed in the same leaf item. */ if (size > old_data_len) btrfs_extend_item(fs_info, path, size - old_data_len); else if (size < old_data_len) btrfs_truncate_item(fs_info, path, data_size, 1); } else { /* There are other xattrs packed in the same item. */ ret = btrfs_delete_one_dir_name(trans, root, path, di); if (ret) goto out; btrfs_extend_item(fs_info, path, data_size); } item = btrfs_item_nr(slot); ptr = btrfs_item_ptr(leaf, slot, char); ptr += btrfs_item_size(leaf, item) - data_size; di = (struct btrfs_dir_item *)ptr; btrfs_set_dir_data_len(leaf, di, size); data_ptr = ((unsigned long)(di + 1)) + name_len; write_extent_buffer(leaf, value, data_ptr, size); btrfs_mark_buffer_dirty(leaf); } else { /* * Insert, and we had space for the xattr, so path->slots[0] is * where our xattr dir_item is and btrfs_insert_xattr_item() * filled it. */ } out: btrfs_free_path(path); return ret; } /* * @value: "" makes the attribute to empty, NULL removes it */ 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 (btrfs_root_readonly(root)) return -EROFS; 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); ret = do_setxattr(trans, inode, name, value, size, flags); if (ret) goto out; inode_inc_iversion(inode); inode->i_ctime = current_time(inode); set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags); ret = btrfs_update_inode(trans, root, inode); BUG_ON(ret); out: btrfs_end_transaction(trans); return ret; } ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size) { struct btrfs_key key; struct inode *inode = d_inode(dentry); struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); struct btrfs_root *root = BTRFS_I(inode)->root; struct btrfs_path *path; int ret = 0; size_t total_size = 0, size_left = size; /* * 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 = btrfs_ino(BTRFS_I(inode)); key.type = BTRFS_XATTR_ITEM_KEY; key.offset = 0; path = btrfs_alloc_path(); if (!path) return -ENOMEM; path->reada = READA_FORWARD; /* search for our xattrs */ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto err; while (1) { struct extent_buffer *leaf; int slot; struct btrfs_dir_item *di; struct btrfs_key found_key; u32 item_size; u32 cur; 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 (found_key.type > BTRFS_XATTR_ITEM_KEY) break; if (found_key.type < BTRFS_XATTR_ITEM_KEY) goto next_item; di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); item_size = btrfs_item_size_nr(leaf, slot); cur = 0; while (cur < item_size) { u16 name_len = btrfs_dir_name_len(leaf, di); u16 data_len = btrfs_dir_data_len(leaf, di); u32 this_len = sizeof(*di) + name_len + data_len; unsigned long name_ptr = (unsigned long)(di + 1); if (verify_dir_item(fs_info, leaf, di)) { ret = -EIO; goto err; } 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; } read_extent_buffer(leaf, buffer, name_ptr, name_len); buffer[name_len] = '\0'; size_left -= name_len + 1; buffer += name_len + 1; next: cur += this_len; di = (struct btrfs_dir_item *)((char *)di + this_len); } next_item: path->slots[0]++; } ret = total_size; err: btrfs_free_path(path); return ret; } static int btrfs_xattr_handler_get(const struct xattr_handler *handler, struct dentry *unused, struct inode *inode, const char *name, void *buffer, size_t size) { name = xattr_full_name(handler, name); return __btrfs_getxattr(inode, name, buffer, size); } static int btrfs_xattr_handler_set(const struct xattr_handler *handler, struct dentry *unused, struct inode *inode, const char *name, const void *buffer, size_t size, int flags) { name = xattr_full_name(handler, name); return __btrfs_setxattr(NULL, inode, name, buffer, size, flags); } static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler, struct dentry *unused, struct inode *inode, const char *name, const void *value, size_t size, int flags) { name = xattr_full_name(handler, name); return btrfs_set_prop(inode, name, value, size, flags); } static const struct xattr_handler btrfs_security_xattr_handler = { .prefix = XATTR_SECURITY_PREFIX, .get = btrfs_xattr_handler_get, .set = btrfs_xattr_handler_set, }; static const struct xattr_handler btrfs_trusted_xattr_handler = { .prefix = XATTR_TRUSTED_PREFIX, .get = btrfs_xattr_handler_get, .set = btrfs_xattr_handler_set, }; static const struct xattr_handler btrfs_user_xattr_handler = { .prefix = XATTR_USER_PREFIX, .get = btrfs_xattr_handler_get, .set = btrfs_xattr_handler_set, }; static const struct xattr_handler btrfs_btrfs_xattr_handler = { .prefix = XATTR_BTRFS_PREFIX, .get = btrfs_xattr_handler_get, .set = btrfs_xattr_handler_set_prop, }; const struct xattr_handler *btrfs_xattr_handlers[] = { &btrfs_security_xattr_handler, #ifdef CONFIG_BTRFS_FS_POSIX_ACL &posix_acl_access_xattr_handler, &posix_acl_default_xattr_handler, #endif &btrfs_trusted_xattr_handler, &btrfs_user_xattr_handler, &btrfs_btrfs_xattr_handler, NULL, }; static int btrfs_initxattrs(struct inode *inode, const struct xattr *xattr_array, void *fs_info) { const struct xattr *xattr; struct btrfs_trans_handle *trans = fs_info; char *name; int err = 0; for (xattr = xattr_array; xattr->name != NULL; xattr++) { name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(xattr->name) + 1, GFP_KERNEL); if (!name) { err = -ENOMEM; break; } strcpy(name, XATTR_SECURITY_PREFIX); strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name); err = __btrfs_setxattr(trans, inode, name, xattr->value, xattr->value_len, 0); kfree(name); if (err < 0) break; } return err; } int btrfs_xattr_security_init(struct btrfs_trans_handle *trans, struct inode *inode, struct inode *dir, const struct qstr *qstr) { return security_inode_init_security(inode, dir, qstr, &btrfs_initxattrs, trans); }