Re: [PATCH v3] vt: fix memory overlapping when deleting chars in the buffer

From: Greg Kroah-Hartman
Date: Thu Jun 30 2022 - 11:18:31 EST


On Tue, Jun 28, 2022 at 05:33:22PM +0800, Yangxi Xiang wrote:
> A memory overlapping copy occurs when deleting a long line. This memory
> overlapping copy can cause data corruption when scr_memcpyw is optimized
> to memcpy because memcpy does not ensure its behavior if the destination
> buffer overlaps with the source buffer. The line buffer is not always
> broken, because the memcpy utilizes the hardware acceleration, whose
> result is not deterministic.
>
> Fix this problem by using replacing the scr_memcpyw with scr_memmovew.
>
> Fixes: 81732c3b2fed ("Fix line garbage in virtual console")

Nit, this should have been:
Fixes: 81732c3b2fed ("tty vt: Fix line garbage in virtual console on command line edition")

otherwise our tools complain. I've fixed it up when applying it.

thanks,

greg k-h