Commit 14f59796 authored by Filipe Manana's avatar Filipe Manana Committed by Chris Mason
Browse files

Btrfs: fix use-after-free when cloning a trailing file hole 



The transaction handle was being used after being freed.

Cc: Chris Mason <clm@fb.com>
Signed-off-by: default avatarFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 0aeb8a6e

fs/btrfs/ioctl.c

+9 −11
Original line number Diff line number Diff line
@@ -3142,7 +3142,6 @@ static int clone_finish_inode_update(struct btrfs_trans_handle *trans, 
static void clone_update_extent_map(struct inode *inode,

				    const struct btrfs_trans_handle *trans,

				    const struct btrfs_path *path,

				    struct btrfs_file_extent_item *fi,

				    const u64 hole_offset,

				    const u64 hole_len)

{
@@ -3157,7 +3156,11 @@ static void clone_update_extent_map(struct inode *inode, 
		return;

	}



	if (fi) {

	if (path) {

		struct btrfs_file_extent_item *fi;



		fi = btrfs_item_ptr(path->nodes[0], path->slots[0],

				    struct btrfs_file_extent_item);

		btrfs_extent_item_to_extent_map(inode, path, fi, false, em);

		em->generation = -1;

		if (btrfs_file_extent_type(path->nodes[0], fi) ==
@@ -3511,18 +3514,15 @@ static int btrfs_clone(struct inode *src, struct inode *inode, 
					    btrfs_item_ptr_offset(leaf, slot),

					    size);

				inode_add_bytes(inode, datal);

				extent = btrfs_item_ptr(leaf, slot,

						struct btrfs_file_extent_item);

			}



			/* If we have an implicit hole (NO_HOLES feature). */

			if (drop_start < new_key.offset)

				clone_update_extent_map(inode, trans,

						path, NULL, drop_start,

						NULL, drop_start,

						new_key.offset - drop_start);



			clone_update_extent_map(inode, trans, path,

						extent, 0, 0);

			clone_update_extent_map(inode, trans, path, 0, 0);



			btrfs_mark_buffer_dirty(leaf);

			btrfs_release_path(path);
@@ -3565,12 +3565,10 @@ static int btrfs_clone(struct inode *src, struct inode *inode, 
			btrfs_end_transaction(trans, root);

			goto out;

		}

		clone_update_extent_map(inode, trans, NULL, last_dest_end,

					destoff + len - last_dest_end);

		ret = clone_finish_inode_update(trans, inode, destoff + len,

						destoff, olen);

		if (ret)

			goto out;

		clone_update_extent_map(inode, trans, path, NULL, last_dest_end,

					destoff + len - last_dest_end);

	}



out: