net_util: queue_pair: Avoid panic and handle error properly

This panic was triggered with fuzzing on the virtio-net device. This
commits handles the error explicitly to avoid the panic, which also
makes the fuzzer happy (as panic is treated as bugs).

Signed-off-by: Bo Chen <chen.bo@intel.com>
(cherry picked from commit 4d9a2b17a7)
Signed-off-by: Rob Bradford <robert.bradford@intel.com>

net_util/src/queue_pair.rs

@@ -185,7 +185,7 @@ impl RxVirtio {
                         .translate_gva(access_platform, desc.len() as usize),
                     10,
                 )
-                .unwrap();
+                .ok_or(NetQueuePairError::DescriptorInvalidHeader)?;
             let mut next_desc = Some(desc);
 
             let mut iovecs = Vec::new();
@@ -312,6 +312,8 @@ pub enum NetQueuePairError {
     QueueEnableNotification(virtio_queue::Error),
     #[error("Failed to add used index to the queue: {0}")]
     QueueAddUsed(virtio_queue::Error),
+    #[error("Descriptor with invalid virtio-net header")]
+    DescriptorInvalidHeader,
 }
 
 pub struct NetQueuePair {