[PATCH 3.2 116/126] HID: core: prevent out-of-bound readings

Ben Hutchings
2017-02-15T22:57:18Z

From: Benjamin Tissoires <benjamin.tissoires@redhat.com>

commit 50220dead1650609206efe91f0cc116132d59b3f upstream.

Plugging a Logitech DJ receiver with KASAN activated raises a bunch of
out-of-bound readings.

The fields are allocated up to MAX_USAGE, meaning that potentially, we do
not have enough fields to fit the incoming values.
Add checks and silence KASAN.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/hid/hid-core.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -989,6 +989,7 @@ static void hid_input_field(struct hid_d
/* Ignore report if ErrorRollOver */
if (!(field->flags & HID_MAIN_ITEM_VARIABLE) &&
value[n] >= min && value[n] <= max &&
+ value[n] - min < field->maxusage &&
field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1)
goto exit;
}
@@ -1001,11 +1002,13 @@ static void hid_input_field(struct hid_d
}

if (field->value[n] >= min && field->value[n] <= max
+ && field->value[n] - min < field->maxusage
&& field->usage[field->value[n] - min].hid
&& search(value, field->value[n], count))
hid_process_event(hid, field, &field->usage[field->value[n] - min], 0, interrupt);

if (value[n] >= min && value[n] <= max
+ && value[n] - min < field->maxusage
&& field->usage[value[n] - min].hid
&& search(field->value, value[n], count))
hid_process_event(hid, field, &field->usage[value[n] - min], 1, interrupt);