block: revert off-by-one error in addr validation

Signed-off-by: Luminita Voicu <[email protected]>

Author: luminitavoicu

src/devices/src/virtio/block/device.rs

@@ -230,10 +230,9 @@ impl Block {
                             e.status()
                         }
                     };
-
-                    if let Err(e) = mem.write_obj(status, request.status_addr) {
-                        error!("Failed to write virtio block status: {:?}", e)
-                    }
+                    // We use unwrap because the request parsing process already checked that the
+                    // status_addr was valid.
+                    mem.write_obj(status, request.status_addr).unwrap();
                 }
                 Err(e) => {
                     error!("Failed to parse available descriptor chain: {:?}", e);
@@ -585,39 +584,6 @@ pub(crate) mod tests {
         assert_eq!(vq.used.ring[0].get().len, 0);
     }
 
-    #[test]
-    fn test_addr_out_of_bounds() {
-        let mut block = default_block();
-        // Default mem size is 0x10000
-        let mem = default_mem();
-        let vq = VirtQueue::new(GuestAddress(0), &mem, 16);
-        block.set_queue(0, vq.create_queue());
-        block.activate(mem.clone()).unwrap();
-        initialize_virtqueue(&vq);
-        vq.dtable[1].set(0xff00, 0x1000, VIRTQ_DESC_F_NEXT | VIRTQ_DESC_F_WRITE, 2);
-
-        let request_type_addr = GuestAddress(vq.dtable[0].addr.get());
-
-        // Mark the next available descriptor.
-        vq.avail.idx.set(1);
-        // Read.
-        {
-            vq.used.idx.set(0);
-
-            mem.write_obj::<u32>(VIRTIO_BLK_T_IN, request_type_addr)
-                .unwrap();
-            vq.dtable[1]
-                .flags
-                .set(VIRTQ_DESC_F_NEXT | VIRTQ_DESC_F_WRITE);
-
-            check_metric_after_block!(
-                &METRICS.block.execute_fails,
-                1,
-                invoke_handler_for_queue_event(&mut block)
-            );
-        }
-    }
-
     #[test]
     fn test_request_execute_failures() {
         let mut block = default_block();
@@ -705,38 +671,6 @@ pub(crate) mod tests {
             VIRTIO_BLK_S_UNSUPP
         );
     }
-    #[test]
-    fn test_end_of_region() {
-        let mut block = default_block();
-        let mem = default_mem();
-        let vq = VirtQueue::new(GuestAddress(0), &mem, 16);
-        block.set_queue(0, vq.create_queue());
-        block.activate(mem.clone()).unwrap();
-        initialize_virtqueue(&vq);
-        vq.dtable[1].set(0xf000, 0x1000, VIRTQ_DESC_F_NEXT | VIRTQ_DESC_F_WRITE, 2);
-
-        let request_type_addr = GuestAddress(vq.dtable[0].addr.get());
-        let status_addr = GuestAddress(vq.dtable[2].addr.get());
-
-        vq.used.idx.set(0);
-
-        mem.write_obj::<u32>(VIRTIO_BLK_T_IN, request_type_addr)
-            .unwrap();
-        vq.dtable[1]
-            .flags
-            .set(VIRTQ_DESC_F_NEXT | VIRTQ_DESC_F_WRITE);
-
-        check_metric_after_block!(
-            &METRICS.block.read_count,
-            1,
-            invoke_handler_for_queue_event(&mut block)
-        );
-
-        assert_eq!(vq.used.idx.get(), 1);
-        assert_eq!(vq.used.ring[0].get().id, 0);
-        assert_eq!(vq.used.ring[0].get().len, vq.dtable[1].len.get());
-        assert_eq!(mem.read_obj::<u32>(status_addr).unwrap(), VIRTIO_BLK_S_OK);
-    }
 
     #[test]
     fn test_read_write() {

src/devices/src/virtio/block/request.rs

@@ -160,7 +160,7 @@ impl Request {
 
             // Check that the address of the data descriptor is valid in guest memory.
             let _ = mem
-                .checked_offset(data_desc.addr, (data_desc.len - 1) as usize)
+                .checked_offset(data_desc.addr, data_desc.len as usize)
                 .ok_or(Error::GuestMemory(GuestMemoryError::InvalidGuestAddress(
                     data_desc.addr,
                 )))?;
@@ -181,7 +181,7 @@ impl Request {
         // Check that the address of the status descriptor is valid in guest memory.
         // We will write an u32 status here after executing the request.
         let _ = mem
-            .checked_offset(status_desc.addr, (mem::size_of::<u32>() - 1) as usize)
+            .checked_offset(status_desc.addr, mem::size_of::<u32>())
             .ok_or(Error::GuestMemory(GuestMemoryError::InvalidGuestAddress(
                 status_desc.addr,
             )))?;