From 15effbaf2a4675df48f2c929b2b77581649f1b82 Mon Sep 17 00:00:00 2001
From: Diego <96022404+dzfrias@users.noreply.github.com>
Date: Mon, 10 Jun 2024 16:10:28 -0700
Subject: [PATCH] LibWasm: Validate that function and code sections match

(cherry picked from commit cda0d6d27746672058b26b0e61d0900dc73b1fb3)
---
 Userland/Libraries/LibWasm/Parser/Parser.cpp | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/Userland/Libraries/LibWasm/Parser/Parser.cpp b/Userland/Libraries/LibWasm/Parser/Parser.cpp
index 4e8283157a..39efe2f57e 100644
--- a/Userland/Libraries/LibWasm/Parser/Parser.cpp
+++ b/Userland/Libraries/LibWasm/Parser/Parser.cpp
@@ -1483,12 +1483,17 @@ bool Module::populate_sections()
 {
     auto is_ok = true;
     FunctionSection const* function_section { nullptr };
+    bool seen_code_section = false;
     for_each_section_of_type<FunctionSection>([&](FunctionSection const& section) { function_section = &section; });
     for_each_section_of_type<CodeSection>([&](CodeSection const& section) {
-        if (!function_section) {
+        if (!function_section && section.functions().is_empty()) {
+            return;
+        }
+        if (!function_section || function_section->types().size() != section.functions().size()) {
             is_ok = false;
             return;
         }
+        seen_code_section = true;
         size_t index = 0;
         for (auto& entry : section.functions()) {
             if (function_section->types().size() <= index) {
@@ -1505,6 +1510,8 @@ bool Module::populate_sections()
             ++index;
         }
     });
+    if (!seen_code_section && function_section && !function_section->types().is_empty())
+        return false;
     return is_ok;
 }