ext4: never move the system.data xattr out of the inode body

commit 8cdb5240ec5928b20490a2bb34cb87e9a5f40226 upstream.

When expanding the extra isize space, we must never move the
system.data xattr out of the inode body.  For performance reasons, it
doesn't make any sense, and the inline data implementation assumes
that system.data xattr is never in the external xattr block.

This addresses CVE-2018-10880

https://bugzilla.kernel.org/show_bug.cgi?id=200005



Bug: 116406509
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Zubin Mithra <zsm@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Git-repo: https://android.googlesource.com/kernel/msm


Git-commit: 2d01420b359016b63d1e29f95d78137b04262bd3
Change-Id: I23ed1d9ebfc7d765bbfd5bdbeb157471989d9926
Signed-off-by: Srinivasa Rao Kuppala <srkupp@codeaurora.org>