From 4f2d898a51ad2276c469f7d00b2353f08c5c4db7 Mon Sep 17 00:00:00 2001
From: Ali Mohammad Pur <ali.mpfard@gmail.com>
Date: Tue, 15 Feb 2022 03:05:49 +0330
Subject: [PATCH] LibWasm: Make MemoryInstance allocation fail if initial
 growth fails

...instead of silently ignoring the failure in the constructor.
---
 .../LibWasm/AbstractMachine/AbstractMachine.cpp   |  6 +++++-
 .../LibWasm/AbstractMachine/AbstractMachine.h     | 15 ++++++++++++---
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/Userland/Libraries/LibWasm/AbstractMachine/AbstractMachine.cpp b/Userland/Libraries/LibWasm/AbstractMachine/AbstractMachine.cpp
index 6893296e29..49d8abc741 100644
--- a/Userland/Libraries/LibWasm/AbstractMachine/AbstractMachine.cpp
+++ b/Userland/Libraries/LibWasm/AbstractMachine/AbstractMachine.cpp
@@ -43,7 +43,11 @@ Optional<TableAddress> Store::allocate(TableType const& type)
 Optional<MemoryAddress> Store::allocate(MemoryType const& type)
 {
     MemoryAddress address { m_memories.size() };
-    m_memories.empend(MemoryInstance { type });
+    auto instance = MemoryInstance::create(type);
+    if (instance.is_error())
+        return {};
+
+    m_memories.append(instance.release_value());
     return address;
 }
 
diff --git a/Userland/Libraries/LibWasm/AbstractMachine/AbstractMachine.h b/Userland/Libraries/LibWasm/AbstractMachine/AbstractMachine.h
index d94478e5ef..3278063c12 100644
--- a/Userland/Libraries/LibWasm/AbstractMachine/AbstractMachine.h
+++ b/Userland/Libraries/LibWasm/AbstractMachine/AbstractMachine.h
@@ -331,10 +331,14 @@ private:
 
 class MemoryInstance {
 public:
-    explicit MemoryInstance(MemoryType const& type)
-        : m_type(type)
+    static ErrorOr<MemoryInstance> create(MemoryType const& type)
     {
-        grow(m_type.limits().min() * Constants::page_size);
+        MemoryInstance instance { type };
+
+        if (!instance.grow(type.limits().min() * Constants::page_size))
+            return Error::from_string_literal("Failed to grow to requested size");
+
+        return { move(instance) };
     }
 
     auto& type() const { return m_type; }
@@ -364,6 +368,11 @@ public:
     }
 
 private:
+    explicit MemoryInstance(MemoryType const& type)
+        : m_type(type)
+    {
+    }
+
     MemoryType const& m_type;
     size_t m_size { 0 };
     ByteBuffer m_data;