Limited Deserialize isn't limiting anything (#10952)

* Add failing test

* Use deserialize_from to enable limit

sdk/src/program_utils.rs

@@ -9,6 +9,27 @@ where
     let limit = crate::packet::PACKET_DATA_SIZE as u64;
     bincode::config()
         .limit(limit)
-        .deserialize(instruction_data)
+        .deserialize_from(instruction_data)
         .map_err(|_| InstructionError::InvalidInstructionData)
 }
+
+#[cfg(test)]
+pub mod tests {
+    use super::*;
+
+    #[test]
+    fn test_limited_deserialize() {
+        #[derive(Deserialize, Serialize)]
+        enum Foo {
+            Bar(Vec<u8>),
+        }
+
+        let item = Foo::Bar([1; crate::packet::PACKET_DATA_SIZE - 12].to_vec()); // crate::packet::PACKET_DATA_SIZE - 12: size limit, minus enum variant and vec len() serialized sizes
+        let serialized = bincode::serialize(&item).unwrap();
+        assert!(limited_deserialize::<Foo>(&serialized).is_ok());
+
+        let item = Foo::Bar([1; crate::packet::PACKET_DATA_SIZE - 11].to_vec()); // Extra byte should bump serialized size over the size limit
+        let serialized = bincode::serialize(&item).unwrap();
+        assert!(limited_deserialize::<Foo>(&serialized).is_err());
+    }
+}