Input: ff-memless - fix signed to unsigned bit overflow
When userspace sets effect->u.rumble.strong_magnitude to 0x8001 or
larger, ml_combine_effects() would always return strong_magnitude
0xffff.
Problem is that 'gain' is passed in as signed integer. Multiplying
magnitude (__u16) with gain (int) causes magnitude read as signed and
results negative value (with magnitude > 0x8000). This signed integer
is then divided and value, still negative, converted to 32bit unsigned
integer. Finally checking combine overflow min(new+old, 0xffff) gives
out 0xffff.
Fix is to simply change 'gain' to unsigned int.
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Acked-by: Anssi Hannula <anssi.hannula@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/ff-memless.c b/drivers/input/ff-memless.c
index bc4e40f..2d1415e 100644
--- a/drivers/input/ff-memless.c
+++ b/drivers/input/ff-memless.c
@@ -226,7 +226,7 @@
*/
static void ml_combine_effects(struct ff_effect *effect,
struct ml_effect_state *state,
- int gain)
+ unsigned int gain)
{
struct ff_effect *new = state->effect;
unsigned int strong, weak, i;