[PATCH 1/2] HID: roccat: bound device-supplied profile index

[Michael Bommarito <michael.bommarito@gmail.com>]

kone_keep_values_up_to_date() and kone_profile_activated() use an
8-bit, device-supplied profile value as an index into the 5-element
kone->profiles[] array without a range check. A malicious USB device
claiming the Roccat Kone id can send a switch-profile event (or a
startup_profile read at probe) with an out-of-range value and make the
driver read out of bounds; the result is exposed via the actual_dpi
sysfs attribute.

Reject out-of-range indices in both paths.

This was found with static analysis and confirmed with the KUnit test
added in the following patch (KASAN: slab-out-of-bounds).

Fixes: 14bf62cde7942 ("HID: add driver for Roccat Kone gaming mouse")
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
---
 drivers/hid/hid-roccat-kone.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/hid-roccat-kone.c b/drivers/hid/hid-roccat-kone.c
index 58654cf78f0df..17495fcc8b7da 100644
--- a/drivers/hid/hid-roccat-kone.c
+++ b/drivers/hid/hid-roccat-kone.c
@@ -36,6 +36,8 @@ static uint profile_numbers[5] = {0, 1, 2, 3, 4};
 
 static void kone_profile_activated(struct kone_device *kone, uint new_profile)
 {
+	if (new_profile < 1 || new_profile > ARRAY_SIZE(kone->profiles))
+		new_profile = 1;
 	kone->actual_profile = new_profile;
 	kone->actual_dpi = kone->profiles[new_profile - 1].startup_dpi;
 }
@@ -793,8 +795,10 @@ static void kone_keep_values_up_to_date(struct kone_device *kone,
 {
 	switch (event->event) {
 	case kone_mouse_event_switch_profile:
-		kone->actual_dpi = kone->profiles[event->value - 1].
-				startup_dpi;
+		if (event->value >= 1 &&
+		    event->value <= ARRAY_SIZE(kone->profiles))
+			kone->actual_dpi =
+				kone->profiles[event->value - 1].startup_dpi;
 		fallthrough;
 	case kone_mouse_event_osd_profile:
 		kone->actual_profile = event->value;
-- 
2.53.0