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virtio_net: fix write_data delivering corrupt packets on guest memory failure #2887

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virtio_net: fix write_data delivering corrupt packets on guest memory failure #2887

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22 changes: 15 additions & 7 deletions vm/devices/virtio/virtio_net/src/buffers.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -77,14 +77,18 @@ impl BufferAccess for VirtioWorkPool {
fn write_data(&mut self, id: RxId, data: &[u8]) {
let mut locked_packet = self.rx_packets[id.0 as usize].lock();
let work = locked_packet.work.as_ref().expect("invalid buffer index");
if let Err(err) = work.write_at_offset(header_size() as u64, &self.mem, data) {
tracing::warn!(
len = data.len(),
error = &err as &dyn std::error::Error,
"rx memory write failure"
);
match work.write_at_offset(header_size() as u64, &self.mem, data) {
Ok(()) => {
locked_packet.len = (header_size() + data.len()) as u32;
}
Err(err) => {
tracing::warn!(
len = data.len(),
error = &err as &dyn std::error::Error,
"rx memory write failure"
);
}
}
locked_packet.len = (header_size() + data.len()) as u32;
}

fn guest_addresses(&mut self, id: RxId) -> &[RxBufferSegment] {
Expand Down Expand Up @@ -124,6 +128,10 @@ impl BufferAccess for VirtioWorkPool {
..FromZeros::new_zeroed()
};
let locked_packet = self.rx_packets[id.0 as usize].lock();
if locked_packet.len == 0 {
// write_data failed; skip header and let the packet complete with zero length.
return;
}
let work = locked_packet.work.as_ref().expect("invalid buffer index");
assert_eq!(metadata.len + header_size(), locked_packet.len as usize);
if let Err(err) = work.write(&self.mem, &virtio_net_header.as_bytes()[..header_size()]) {
Expand Down