linux/fs/overlayfs
yangerkun 9a25440376 ovl: fix use after free in struct ovl_aio_req
Example for triggering use after free in a overlay on ext4 setup:

aio_read
  ovl_read_iter
    vfs_iter_read
      ext4_file_read_iter
        ext4_dio_read_iter
          iomap_dio_rw -> -EIOCBQUEUED
          /*
	   * Here IO is completed in a separate thread,
	   * ovl_aio_cleanup_handler() frees aio_req which has iocb embedded
	   */
          file_accessed(iocb->ki_filp); /**BOOM**/

Fix by introducing a refcount in ovl_aio_req similarly to aio_kiocb.  This
guarantees that iocb is only freed after vfs_read/write_iter() returns on
underlying fs.

Fixes: 2406a307ac ("ovl: implement async IO routines")
Signed-off-by: yangerkun <yangerkun@huawei.com>
Link: https://lore.kernel.org/r/20210930032228.3199690-3-yangerkun@huawei.com/
Cc: <stable@vger.kernel.org> # v5.6
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-10-29 13:48:19 +02:00
..
copy_up.c ovl: use kvalloc in xattr copy-up 2021-08-17 11:47:45 +02:00
dir.c ovl: fix missing negative dentry check in ovl_rename() 2021-09-24 21:00:31 +02:00
export.c ovl: fix uninitialized pointer read in ovl_lookup_real_one() 2021-08-10 10:21:30 +02:00
file.c ovl: fix use after free in struct ovl_aio_req 2021-10-29 13:48:19 +02:00
inode.c ovl: enable RCU'd ->get_acl() 2021-08-18 22:08:24 +02:00
Kconfig docs: fix broken references to text files 2020-04-20 15:35:59 -06:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
namei.c ovl: relax lookup error on mismatch origin ftype 2021-08-17 11:47:44 +02:00
overlayfs.h vfs: add rcu argument to ->get_acl() callback 2021-08-18 22:08:24 +02:00
ovl_entry.h ovl: implement volatile-specific fsync error behaviour 2021-01-28 10:22:48 +01:00
readdir.c ovl: skip stale entries in merge dir cache iteration 2021-08-10 10:21:30 +02:00
super.c ovl: add ovl_allow_offline_changes() helper 2021-08-17 11:47:44 +02:00
util.c ovl: consistent behavior for immutable/append-only inodes 2021-08-17 11:47:43 +02:00