check for null fields on deserialization

oxidecomputer · May 31, 2024 · 7b068cb · 7b068cb
1 parent 53d2cfd
commit 7b068cb
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/codegen/rust/src/header.rs b/codegen/rust/src/header.rs
@@ -99,7 +99,11 @@ impl<'a> HeaderGenerator<'a> {
                     let n = (#end-#offset);
                     let m = n%8;
                     let mut b = BitVec::<u8, Msb0>::from_vec(v);
-                    x[#offset..#end] |= &b[m..];
+                    // this field may be null so check that we at least have
+                    // enough space to offset
+                    if b.len() > m {
+                        x[#offset..#end] |= &b[m..];
+                    }
                 } else {
                     x[#offset..#end] |= self.#name.to_owned();
                 }