From 14d7bcfaed67f59af1fb43e1fb272f14f90889c3 Mon Sep 17 00:00:00 2001
From: Takeshi Yoneda <takeshi@tetrate.io>
Date: Wed, 20 Apr 2022 10:54:12 +0900
Subject: [PATCH] Fix validate start section with imports (#485)

Signed-off-by: Takeshi Yoneda <takeshi@tetrate.io>
---
 internal/wasm/module.go      |  4 ++--
 internal/wasm/module_test.go | 15 +++++++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/internal/wasm/module.go b/internal/wasm/module.go
index f350d61c..3d8a6931 100644
--- a/internal/wasm/module.go
+++ b/internal/wasm/module.go
@@ -191,9 +191,9 @@ func (m *Module) TypeOfFunction(funcIdx Index) *FunctionType {
 		return nil
 	}
 	funcImportCount := Index(0)
-	for i, im := range m.ImportSection {
+	for _, im := range m.ImportSection {
 		if im.Type == ExternTypeFunc {
-			if funcIdx == Index(i) {
+			if funcIdx == funcImportCount {
 				if im.DescFunc >= typeSectionLength {
 					return nil
 				}
diff --git a/internal/wasm/module_test.go b/internal/wasm/module_test.go
index 196f823e..0bd3e33c 100644
--- a/internal/wasm/module_test.go
+++ b/internal/wasm/module_test.go
@@ -331,6 +331,21 @@ func TestModule_validateStartSection(t *testing.T) {
 			})
 		}
 	})
+	t.Run("imported valid func", func(t *testing.T) {
+		index := Index(1)
+		m := Module{
+			StartSection: &index,
+			TypeSection:  []*FunctionType{{}, {Results: []ValueType{ValueTypeI32}}},
+			ImportSection: []*Import{
+				{Type: ExternTypeFunc, DescFunc: 1},
+				// import with index 1 is global but this should be skipped when searching imported functions.
+				{Type: ExternTypeGlobal},
+				{Type: ExternTypeFunc, DescFunc: 0}, // This one must be selected.
+			},
+		}
+		err := m.validateStartSection()
+		require.NoError(t, err)
+	})
 }
 
 func TestModule_validateGlobals(t *testing.T) {