Make Module::new perform validation. (#621)

* Make `Module::new` perform validation.

As noticed in #602, `Module::new` did not perform validation, which
turns out to be error-prone in practice. Rename it to
`Module::new_unchecked`, and add a new `Module::new` which does
perform validation.

Preserve wasm-c-api's `wasm_module_new`'s behavior by using
`Module::new_unchecked`, and implement `wasm_module_validate`.

* Change `validate`'s store argument to `&HostRef<Store>`.

* Enable multi-value in validation.

crates/api/src/module.rs

@@ -4,8 +4,11 @@ use crate::types::{
     ExportType, ExternType, FuncType, GlobalType, ImportType, Limits, MemoryType, Mutability,
     TableType, ValType,
 };
-use anyhow::Result;
-use wasmparser::{validate, ExternalKind, ImportSectionEntryType, ModuleReader, SectionCode};
+use anyhow::{Error, Result};
+use wasmparser::{
+    validate, ExternalKind, ImportSectionEntryType, ModuleReader, OperatorValidatorConfig,
+    SectionCode, ValidatingParserConfig,
+};
 
 fn into_memory_type(mt: wasmparser::MemoryType) -> MemoryType {
     assert!(!mt.shared);
@@ -184,7 +187,15 @@ pub struct Module {
 }
 
 impl Module {
+    /// Validate and decode the raw wasm data in `binary` and create a new
+    /// `Module` in the given `store`.
     pub fn new(store: &HostRef<Store>, binary: &[u8]) -> Result<Module> {
+        Self::validate(store, binary)?;
+        Self::new_unchecked(store, binary)
+    }
+    /// Similar to `new`, but does not perform any validation. Only use this
+    /// on modules which are known to have been validated already!
+    pub fn new_unchecked(store: &HostRef<Store>, binary: &[u8]) -> Result<Module> {
         let (imports, exports) = read_imports_and_exports(binary)?;
         Ok(Module {
             store: store.clone(),
@@ -199,8 +210,17 @@ impl Module {
             _ => None,
         }
     }
-    pub fn validate(_store: &Store, binary: &[u8]) -> bool {
-        validate(binary, None).is_ok()
+    pub fn validate(_store: &HostRef<Store>, binary: &[u8]) -> Result<()> {
+        let config = ValidatingParserConfig {
+            operator_config: OperatorValidatorConfig {
+                enable_threads: false,
+                enable_reference_types: false,
+                enable_bulk_memory: false,
+                enable_simd: false,
+                enable_multi_value: true,
+            },
+        };
+        validate(binary, Some(config)).map_err(Error::new)
     }
     pub fn imports(&self) -> &[ImportType] {
         &self.imports

crates/api/src/wasm.rs

@@ -722,6 +722,8 @@ impl wasm_name_t {
     }
 }
 
+/// Note that this function does not perform validation on the wasm
+/// binary. To perform validation, use `wasm_module_validate`.
 #[no_mangle]
 pub unsafe extern "C" fn wasm_module_new(
     store: *mut wasm_store_t,
@@ -729,7 +731,7 @@ pub unsafe extern "C" fn wasm_module_new(
 ) -> *mut wasm_module_t {
     let binary = (*binary).as_slice();
     let store = &(*store).store;
-    let module = Module::new(store, binary).expect("module");
+    let module = Module::new_unchecked(store, binary).expect("module");
     let imports = module
         .imports()
         .iter()
@@ -756,6 +758,16 @@ pub unsafe extern "C" fn wasm_module_new(
     Box::into_raw(module)
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn wasm_module_validate(
+    store: *mut wasm_store_t,
+    binary: *const wasm_byte_vec_t,
+) -> bool {
+    let binary = (*binary).as_slice();
+    let store = &(*store).store;
+    Module::validate(store, binary).is_ok()
+}
+
 #[no_mangle]
 pub unsafe extern "C" fn wasm_store_delete(store: *mut wasm_store_t) {
     let _ = Box::from_raw(store);