Re: [PATCH] pxa3xx-gcu: Fix integer overflow in pxa3xx_gcu_write
Dan Carpenter <dan.carpenter@...>
On Tue, Sep 20, 2022 at 09:02:34AM +0300, Dan Carpenter wrote:
On Mon, Jun 20, 2022 at 07:00:10AM -0700, Hyunwoo Kim wrote:Btw, the other thing which prevents this from being expliotable is thatIn pxa3xx_gcu_write, a count parameter ofThe count variable is actually capped at MAX_RW_COUNT in vfs_write()
if you pass a negative value to copy_from_user() it will not copy
anything because of the check in check_copy_size(). See commit
6d13de1489b6 ("uaccess: disallow > INT_MAX copy sizes").
Linus has sort of gotten annoyed with me before for pointing this stuff
out because it seemed like maybe I wasn't properly grateful to people
auditing the code and fixing bugs. I am grateful. This patch is
totally the correct thing to do. It's just that it's not really
exploitable as described in the commit message.