jfs: xattr: fix buffer overflow for invalid xattr

commit 7c55b78818cfb732680c4a72ab270cc2d2ee3d0f upstream.

When an xattr size is not what is expected, it is printed out to the
kernel log in hex format as a form of debugging.  But when that xattr
size is bigger than the expected size, printing it out can cause an
access off the end of the buffer.

Fix this all up by properly restricting the size of the debug hex dump
in the kernel log.

Reported-by:  <syzbot+9dfe490c8176301c1d06@syzkaller.appspotmail.com>
Cc: Dave Kleikamp <shaggy@kernel.org>
Link: https://lore.kernel.org/r/2024051433-slider-cloning-98f9@gregkh


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>