From e96bb3dfeda472e1d721ded85758936e69a1ea86 Mon Sep 17 00:00:00 2001
From: Alex Crichton <alex@alexcrichton.com>
Date: Wed, 8 Jul 2020 07:36:35 -0700
Subject: [PATCH] Disallow module linking sections by default

Only allow module linking sections, even if they're empty, to show up if
the module linking feature is enabled.
---
 crates/wasmparser/src/validator.rs                    | 5 +++++
 tests/local/missing-features/linking-not-enabled.wast | 7 +++++++
 tests/roundtrip.rs                                    | 2 +-
 3 files changed, 13 insertions(+), 1 deletion(-)
 create mode 100644 tests/local/missing-features/linking-not-enabled.wast

diff --git a/crates/wasmparser/src/validator.rs b/crates/wasmparser/src/validator.rs
index d8fbe2b317..2abe3bf347 100644
--- a/crates/wasmparser/src/validator.rs
+++ b/crates/wasmparser/src/validator.rs
@@ -610,6 +610,11 @@ impl<'a> ValidatingParser<'a> {
             Some(state) => state,
             None => return Ok(self.cur_module().section_order_state),
         };
+        if state == SectionOrderState::ModuleLinkingHeader
+            && !self.config.operator_config.enable_module_linking
+        {
+            return self.create_error("module linking proposal not enabled");
+        }
         Ok(match self.cur_module().section_order_state {
             // Did we just start? In that case move to our newly-found state.
             Initial => state,
diff --git a/tests/local/missing-features/linking-not-enabled.wast b/tests/local/missing-features/linking-not-enabled.wast
new file mode 100644
index 0000000000..9de4cc48a4
--- /dev/null
+++ b/tests/local/missing-features/linking-not-enabled.wast
@@ -0,0 +1,7 @@
+(assert_invalid
+  (module binary
+    "\00asm"
+    "\01\00\00\00"
+    "\64\01\00"
+    )
+  "module linking proposal not enabled")
diff --git a/tests/roundtrip.rs b/tests/roundtrip.rs
index 5a3ed63a0d..7707f67b32 100644
--- a/tests/roundtrip.rs
+++ b/tests/roundtrip.rs
@@ -665,7 +665,7 @@ impl TestState {
         };
         for part in test.iter().filter_map(|t| t.to_str()) {
             match part {
-                "testsuite" | "wasmtime905.wast" => {
+                "testsuite" | "wasmtime905.wast" | "missing-features" => {
                     config.operator_config.enable_threads = false;
                     config.operator_config.enable_reference_types = false;
                     config.operator_config.enable_simd = false;