tree f65297c240b266b282dc2d743da89a5e8f975c03
parent c907ce3fd5528cf0483bcac7db55a3d82d35e000
author Sriram Rajagopalan <sriramr@arista.com> 1557530886 -0400
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1558503464 +0200

ext4: zero out the unused memory region in the extent tree block

commit 592acbf16821288ecdc4192c47e3774a4c48bb64 upstream.

This commit zeroes out the unused memory region in the buffer_head
corresponding to the extent metablock after writing the extent header
and the corresponding extent node entries.

This is done to prevent random uninitialized data from getting into
the filesystem when the extent block is synced.

This fixes CVE-2019-11833.

Signed-off-by: Sriram Rajagopalan <sriramr@arista.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>