On 2020-08-27 10:33, Jiri Kosina 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@vger.kernel.org Signed-off-by: Marc Zyngier maz@kernel.org
- 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.
I found yet another nit that this patch doesn't quite catch. v3 going out in a minute.
Thanks,
M.