[sui-types] Update bounded visitor to take an environment variable override at startup

crates/sui-types/src/object/bounded_visitor.rs

@@ -9,6 +9,8 @@ use move_core_types::{
  language_storage::TypeTag,
  u256::U256,
 };
+use once_cell::sync::Lazy;
+use tracing::info;
 
 /// Visitor to deserialize annotated values or structs, bounding the size budgeted for types and
 /// field names in the output. The visitor does not bound the size of values, because they are
@@ -27,12 +29,46 @@ pub enum Error {
  OutOfBudget,
 }
 
-/// Initial budget for deserialization -- we're okay to spend an extra ~1MiB on types and field
+/// Environment variable to override the default budget for deserialization. This can be set at
+/// runtime to change the maximum size of values that can be deserialized.
+const MAX_BOUND_VAR_NAME: &str = "MAX_ANNOTATED_VALUE_SIZE";
+
+/// Default budget for deserialization -- we're okay to spend an extra ~1MiB on types and field
 /// information per value.
+const DEFAULT_MAX_BOUND: usize = 1024 * 1024;
+
+/// Budget for deserialization into an annotated Move value. This sets the numbers of bytes that we
+/// are willing to spend on field names, type names (etc) when deserializing a Move value into an
+/// annotated Move value.
+///
+/// Bounded deserialization is intended for use outside of the validator, and so uses a fixed bound
+/// that needs to be set at startup rather than one that is configured as part of the protocol.
 ///
-/// Bounded deserialization is intended for use outside of the validator, and so uses a fixed bound,
-/// rather than one that is configured as part of the protocol.
-const MAX_BOUND: usize = 1024 * 1024;
+/// If the environment variable `MAX_ANNOTATED_VALUE_SIZE` is unset we default to
+/// `DEFAULT_MAX_BOUND` which allows ~1MiB additional space usage on types and field information
+/// per value.
+///
+/// This is read only once and after that the value is cached. To change this value you will need
+/// to restart the process with the new value set (or the value unset if you wish to use the
+/// `DEFAULT_MAX_BOUND` value).
+static MAX_BOUND: Lazy<usize> = Lazy::new(|| {
+ let max_bound_opt = std::env::var(MAX_BOUND_VAR_NAME)
+ .ok()
+ .and_then(|s| s.parse().ok());
+ if let Some(max_bound) = max_bound_opt {
+ info!(
+ "Using custom value for '{}' max bound: {}",
+ MAX_BOUND_VAR_NAME, max_bound
+ );
+ max_bound
+ } else {
+ info!(
+ "Using default value for '{}' -- max bound: {}",
+ MAX_BOUND_VAR_NAME, DEFAULT_MAX_BOUND
+ );
+ DEFAULT_MAX_BOUND
+ }
+});
 
 impl BoundedVisitor {
  fn new(bound: usize) -> Self {
@@ -221,7 +257,7 @@ impl Visitor for BoundedVisitor {
 
 impl Default for BoundedVisitor {
  fn default() -> Self {
- Self::new(MAX_BOUND)
+ Self::new(*MAX_BOUND)
  }
 }
 
@@ -264,6 +300,60 @@ mod tests {
  assert_eq!(value, deser);
  }
 
+ #[test]
+ fn test_env_variable_override() {
+ use A::MoveTypeLayout as T;
+ use A::MoveValue as V;
+
+ let type_layout = layout_(
+ "0x0::foo::Bar",
+ vec![
+ ("a", T::U64),
+ ("b", T::Vector(Box::new(T::U64))),
+ ("c", layout_("0x0::foo::Baz", vec![("d", T::U64)])),
+ ],
+ );
+
+ let value = value_(
+ "0x0::foo::Bar",
+ vec![
+ ("a", V::U64(42)),
+ ("b", V::Vector(vec![V::U64(43)])),
+ ("c", value_("0x0::foo::Baz", vec![("d", V::U64(44))])),
+ ],
+ );
+
+ let bytes = serialize(value.clone());
+
+ let before_value = std::env::var(MAX_BOUND_VAR_NAME).ok();
+
+ std::env::set_var(MAX_BOUND_VAR_NAME, "10");
+ let mut visitor = BoundedVisitor::default();
+ let err = A::MoveValue::visit_deserialize(&bytes, &type_layout, &mut visitor).unwrap_err();
+ let expect = expect!["Deserialized value too large"];
+ expect.assert_eq(&err.to_string());
+
+ // Should be unaffected as we already set the value, so this should still fail.
+ std::env::set_var(MAX_BOUND_VAR_NAME, "1000");
+ let mut visitor = BoundedVisitor::default();
+ let err = A::MoveValue::visit_deserialize(&bytes, &type_layout, &mut visitor).unwrap_err();
+ let expect = expect!["Deserialized value too large"];
+ expect.assert_eq(&err.to_string());
+
+ // set the value back to what it was before if it was previously set, otherwise unset it.
+ if let Some(previous_value) = before_value {
+ std::env::set_var(MAX_BOUND_VAR_NAME, previous_value);
+ } else {
+ std::env::remove_var(MAX_BOUND_VAR_NAME);
+ }
+
+ // Should still fail as the static value is already set.
+ let mut visitor = BoundedVisitor::default();
+ let err = A::MoveValue::visit_deserialize(&bytes, &type_layout, &mut visitor).unwrap_err();
+ let expect = expect!["Deserialized value too large"];
+ expect.assert_eq(&err.to_string());
+ }
+
  #[test]
  fn test_too_deep() {
  use A::MoveTypeLayout as T;