[PATCH] HID: pidff: fix undefined shift for infinite duration

DORMANTno replies

From: Shengzhuo Wei <hidden>
Date: 2026-10-28 10:55:22
Also in: linux-usb, lkml, stable
Subsystem: hid core layer, the rest, usb hid pid drivers (usb wheelbases, joysticks, rudders, ...), usb hid/hidbp drivers (usb keyboards, mice, remote controls, ...) · Maintainers: Jiri Kosina, Benjamin Tissoires, Linus Torvalds, Tomasz Pakuła, Oleg Makarenko

pidff_set_duration() computes the infinite duration as
(1U << report_size) - 1, but report_size comes from the device's
report descriptor and can be 32 or greater. This causes an undefined
shift. A UHID test on x86-64 triggers UBSAN and programs a 32-bit
duration field as zero instead of 0xffffffff.

For report sizes of 32 or more, store -1 in the s32 field value to
set all 32 bits without shifting. Keep the existing calculation for
smaller fields.

Fixes: 1a575044d516 ("HID: pidff: Compute INFINITE value instead of using hardcoded 0xffff")
Cc: <redacted>
Signed-off-by: Shengzhuo Wei <redacted>
---
HID: pidff: fix undefined shift for infinite duration
---
 drivers/hid/usbhid/hid-pidff.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/hid/usbhid/hid-pidff.c b/drivers/hid/usbhid/hid-pidff.c
index 22951b7ecd17..25b82e7d0b9e 100644
--- a/drivers/hid/usbhid/hid-pidff.c
+++ b/drivers/hid/usbhid/hid-pidff.c
@@ -394,7 +394,11 @@ static void pidff_set_duration(struct pidff_usage *usage, u16 duration)
 {
 	/* PID defines INFINITE as the max possible value for duration field */
 	if (pidff_is_duration_infinite(duration)) {
-		usage->value[0] = (1U << usage->field->report_size) - 1;
+		if (usage->field->report_size >= 32)
+			usage->value[0] = -1;
+		else
+			usage->value[0] =
+				(1U << usage->field->report_size) - 1;
 		return;
 	}
 
---
base-commit: d135ab453a7400a34930bdda1ef4bdc8acfac80e
change-id: 20261028-b4-pidff-duration-shift-8df4f6451448

Best regards,
--  
Shengzhuo Wei [off-list ref]
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