On Thu, Aug 27, 2020 at 11:33 AM Jiri Kosina <jikos@xxxxxxxxxx> wrote: > > On Wed, 26 Aug 2020, Marc Zyngier wrote: > > > When calling into hid_map_usage(), the passed event code is > > blindly stored as is, even if it doesn't fit in the associated bitmap. > > > > This event code can come from a variety of sources, including devices > > masquerading as input devices, only a bit more "programmable". > > > > Instead of taking the event code at face value, check that it actually > > fits the corresponding bitmap, and if it doesn't: > > - spit out a warning so that we know which device is acting up > > - NULLify the bitmap pointer so that we catch unexpected uses > > > > Code paths that can make use of untrusted inputs can now check > > that the mapping was indeed correct and bail out if not. > > > > Cc: stable@xxxxxxxxxxxxxxx > > Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx> > > --- > > * From v1: > > - Dropped the input.c changes, and turned hid_map_usage() into > > the validation primitive. > > - Handle mapping failures in hidinput_configure_usage() and > > mt_touch_input_mapping() (on top of hid_map_usage_clear() which > > was already handled) > > Benjamin, could you please run this through your regression testing > machinery? > > It's a non-trivial core change, at the same time I'd like not to postpone > it for 5.10 due to its nature. OK, just passed the v4 to the testsuite, and this seems good. It won't break touchscreens nor keyboards/mice that needed to be added in the past. So this is a go for me. Cheers, Benjamin > > Thanks, > > -- > Jiri Kosina > SUSE Labs >
