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HID: core: prevent out-of-bound readings
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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>
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Benjamin Tissoires authored and Jiri Kosina committed Jan 19, 2016
1 parent 5137b35 commit 50220de
Showing 1 changed file with 3 additions and 0 deletions.
3 changes: 3 additions & 0 deletions drivers/hid/hid-core.c
Original file line number Diff line number Diff line change
Expand Up @@ -1293,6 +1293,7 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field,
/* 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;
}
Expand All @@ -1305,11 +1306,13 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field,
}

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);
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