From 4131b3585164761e3841bb1c9609b302658ee2c0 Mon Sep 17 00:00:00 2001 From: Jelle Raaijmakers Date: Sun, 24 Oct 2021 20:29:50 +0200 Subject: [PATCH] Kernel: Prevent VMWareMouseDevice from handling invalid mouse packets Bit 3 is set here: https://github.com/qemu/qemu/blob/c5b2f559814104f4145f8bc310f4d33c7ead8f49/hw/input/ps2.c#L736 Spurious mouse packets can be received without this bit set, for example when double-clicking and keeping the mouse button depressed instead of releasing it the second time (i.e. mousedown > mouseup > mousedown). We should not process such packets. This makes interaction with our buttons much smoother! Fixes #5881. --- Kernel/Devices/HID/VMWareMouseDevice.cpp | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/Kernel/Devices/HID/VMWareMouseDevice.cpp b/Kernel/Devices/HID/VMWareMouseDevice.cpp index f2a6908153..05ba5f0d19 100644 --- a/Kernel/Devices/HID/VMWareMouseDevice.cpp +++ b/Kernel/Devices/HID/VMWareMouseDevice.cpp @@ -25,10 +25,11 @@ UNMAP_AFTER_INIT RefPtr VMWareMouseDevice::try_to_initialize( return {}; } -void VMWareMouseDevice::irq_handle_byte_read(u8) +void VMWareMouseDevice::irq_handle_byte_read(u8 byte) { VERIFY(VMWareBackdoor::the()); VERIFY(VMWareBackdoor::the()->vmmouse_is_absolute()); + // We won't receive complete packets with the backdoor enabled, // we will only get one byte for each event, which we'll just // discard. If we were to wait until we *think* that we got a @@ -36,6 +37,12 @@ void VMWareMouseDevice::irq_handle_byte_read(u8) // because we wouldn't read the appropriate number of mouse // packets from VMWareBackdoor. auto mouse_packet = VMWareBackdoor::the()->receive_mouse_packet(); + + // Only process packets with bit 3 set. + // Note that this needs to happen _after_ invoking receive_mouse_packet() above + if (!(byte & 0x8)) + return; + if (mouse_packet.has_value()) { m_entropy_source.add_random_event(mouse_packet.value()); {