Fake USB devices can send their own report descriptors for which the input_mapping() hook does not get called. In this case, pm->input_ep82 stays NULL, which leads to a crash later.

This does not happen with the real device, but can be provoked by imposing as one.

Cc: stable@vger.kernel.org Signed-off-by: Günther Noack gnoack@google.com --- drivers/hid/hid-prodikeys.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/drivers/hid/hid-prodikeys.c b/drivers/hid/hid-prodikeys.c index 74bddb2c3e82..6e413df38358 100644 --- a/drivers/hid/hid-prodikeys.c +++ b/drivers/hid/hid-prodikeys.c @@ -378,6 +378,10 @@ static int pcmidi_handle_report4(struct pcmidi_snd *pm, u8 *data) bit_mask = (bit_mask << 8) | data[2]; bit_mask = (bit_mask << 8) | data[3];

+ /* robustness in case input_mapping hook does not get called */ + if (!pm->input_ep82) + return 0; + /* break keys */ for (bit_index = 0; bit_index < 24; bit_index++) { if (!((0x01 << bit_index) & bit_mask)) {