Contract import/export validation (#2203)

* Reject validation of contract with unknown exports

* Validate imports eagerly

* Increment spec version

substrate/node/runtime/src/lib.rs

@@ -59,7 +59,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	spec_name: create_runtime_str!("node"),
 	impl_name: create_runtime_str!("substrate-node"),
 	authoring_version: 10,
-	spec_version: 57,
+	spec_version: 58,
 	impl_version: 59,
 	apis: RUNTIME_API_VERSIONS,
 };

substrate/srml/contract/src/wasm/prepare.rs

@@ -108,6 +108,8 @@ impl<'a, Gas: 'a + As<u32> + Clone> ContractModule<'a, Gas> {
 	///
 	/// - 'call'
 	/// - 'deploy'
+	///
+	/// Any other exports are not allowed.
 	fn scan_exports(&self) -> Result<(), &'static str> {
 		let mut deploy_found = false;
 		let mut call_found = false;
@@ -147,7 +149,7 @@ impl<'a, Gas: 'a + As<u32> + Clone> ContractModule<'a, Gas> {
 			match export.field() {
 				"call" => call_found = true,
 				"deploy" => deploy_found = true,
-				_ => continue,
+				_ => return Err("unknown export: expecting only deploy and call functions"),
 			}
 
 			// Then check the export kind. "call" and "deploy" are
@@ -218,12 +220,19 @@ impl<'a, Gas: 'a + As<u32> + Clone> ContractModule<'a, Gas> {
 			}
 
 			let type_idx = match import.external() {
+				&External::Table(_) => return Err("Cannot import tables"),
+				&External::Global(_) => return Err("Cannot import globals"),
 				&External::Function(ref type_idx) => type_idx,
 				&External::Memory(ref memory_type) => {
+					if import.field() != "memory" {
+						return Err("Memory import must have the field name 'memory'")
+					}
+					if imported_mem_type.is_some() {
+						return Err("Multiple memory imports defined")
+					}
 					imported_mem_type = Some(memory_type);
 					continue;
 				}
-				_ => continue,
 			};
 
 			let Type::Function(ref func_ty) = types
@@ -447,6 +456,54 @@ mod tests {
 			"#,
 			Err("Maximum number of pages should not exceed the configured maximum.")
 		);
+
+		prepare_test!(field_name_not_memory,
+			r#"
+			(module
+				(import "env" "forgetit" (memory 1 1))
+
+				(func (export "call"))
+				(func (export "deploy"))
+			)
+			"#,
+			Err("Memory import must have the field name 'memory'")
+		);
+
+		prepare_test!(multiple_memory_imports,
+			r#"
+			(module
+				(import "env" "memory" (memory 1 1))
+				(import "env" "memory" (memory 1 1))
+
+				(func (export "call"))
+				(func (export "deploy"))
+			)
+			"#,
+			Err("Multiple memory imports defined")
+		);
+
+		prepare_test!(table_import,
+			r#"
+			(module
+				(import "env" "table" (table 1 anyfunc))
+
+				(func (export "call"))
+				(func (export "deploy"))
+			)
+			"#,
+			Err("Cannot import tables")
+		);
+
+		prepare_test!(global_import,
+			r#"
+			(module
+				(global $g (import "env" "global") (mut i32))
+				(func (export "call"))
+				(func (export "deploy"))
+			)
+			"#,
+			Err("Cannot import globals")
+		);
 	}
 
 	mod imports {
@@ -582,5 +639,16 @@ mod tests {
 			"#,
 			Err("entry point has wrong signature")
 		);
+
+		prepare_test!(unknown_exports,
+			r#"
+			(module
+				(func (export "call"))
+				(func (export "deploy"))
+				(func (export "whatevs"))
+			)
+			"#,
+			Err("unknown export: expecting only deploy and call functions")
+		);
 	}
 }