devices: acpi: Increase robustness of bus devices

Check the size of data buffer for reading on the ApciPmTimer device to
avoid a potential panic if the guest uses non-DWORD access.

Simplify the zeroring of the buffer for AcpiShutdownDevice.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>
This commit is contained in:
Rob Bradford 2021-09-14 17:02:20 +01:00 committed by Sebastien Boeuf
parent 1d78812b63
commit a77160dca4

View File

@ -34,9 +34,7 @@ impl AcpiShutdownDevice {
impl BusDevice for AcpiShutdownDevice {
// Spec has all fields as zero
fn read(&mut self, _base: u64, _offset: u64, data: &mut [u8]) {
for i in data.iter_mut() {
*i = 0;
}
data.fill(0)
}
fn write(&mut self, _base: u64, _offset: u64, data: &[u8]) -> Option<Arc<Barrier>> {
@ -191,6 +189,10 @@ impl Default for AcpiPmTimerDevice {
impl BusDevice for AcpiPmTimerDevice {
fn read(&mut self, _base: u64, _offset: u64, data: &mut [u8]) {
if data.len() != std::mem::size_of::<u32>() {
warn!("Invalid sized read of PM timer: {}", data.len());
return;
}
let now = Instant::now();
let since = now.duration_since(self.start);
let nanos = since.as_nanos();