tree 91b34125c1a2dee7571abf280818ff88a951e129
parent f81a265f76264a8f7303f164dffed7331a84081e
author Marc Zyngier <maz@kernel.org> 1598953953 +0100
committer Luca Weiss <luca.weiss@fairphone.com> 1626347891 +0200

HID: core: Sanitize event code and type when mapping input

commit 35556bed836f8dc07ac55f69c8d17dce3e7f0e25 upstream.

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>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

(cherry picked from commit ac48d8300edd1aa4ce0fbef0ff5136d363f44cdf)