clone

programs/bpf_loader/src/syscalls/sysvar.rs

@@ -16,7 +16,11 @@ fn get_sysvar<T: std::fmt::Debug + Sysvar + SysvarId + Clone>(
     )?;
     let var = translate_type_mut::<T>(memory_mapping, var_addr, check_aligned)?;
 
-    *var = sysvar?;
+    // this clone looks unecessary, but it exists to zero out trailing alignment bytes
+    // it is unclear whether this should ever matter
+    // but there are tests using MemoryMapping that expect to see this
+    // we preserve the previous behavior out of an abundance of caution
+    *var = sysvar?.clone();
 
     Ok(SUCCESS)
 }