rust: Manually allocate output buffer for Into<evmc_result>

bindings/rust/evmc-vm/src/lib.rs

@@ -88,7 +88,17 @@ impl From<ffi::evmc_result> for ExecutionResult {
 impl Into<*const ffi::evmc_result> for ExecutionResult {
     fn into(self) -> *const ffi::evmc_result {
         let (buffer, len) = if let Some(buf) = self.output {
-            (buf.as_ptr(), buf.len())
+            let buf_len = buf.len();
+
+            // Manually allocate heap memory for the new home of the output buffer.
+            let memlayout = std::alloc::Layout::from_size_align(buf_len, 1).expect("Bad layout");
+            let new_buf = unsafe { std::alloc::alloc(memlayout) };
+            unsafe {
+                // Copy the data into the allocated buffer.
+                std::ptr::copy(buf.as_ptr(), new_buf, buf_len);
+            }
+
+            (new_buf as *const u8, buf_len)
         } else {
             (std::ptr::null(), 0)
         };
@@ -171,7 +181,10 @@ mod tests {
             assert!((*f).gas_left == 420);
             assert!(!(*f).output_data.is_null());
             assert!((*f).output_size == 5);
-            //            assert!(std::slice::from_raw_parts((*f).output_data, 5) as &[u8] == &[0xc0, 0xff, 0xee, 0x71, 0x75]);
+            assert!(
+                std::slice::from_raw_parts((*f).output_data, 5) as &[u8]
+                    == &[0xc0, 0xff, 0xee, 0x71, 0x75]
+            );
             assert!((*f).create_address.bytes == [0u8; 20]);
         }
     }