From 6840a8983cf1b235f8c3e7fe27cd5e9736eceaa9 Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Wed, 29 May 2024 20:01:12 +0300
Subject: [PATCH] Kernel: Make sure MSB is not set on SMO keys

---
 kernel/include/kernel/Memory/SharedMemoryObject.h | 2 +-
 kernel/kernel/Memory/SharedMemoryObject.cpp       | 7 +++++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/kernel/include/kernel/Memory/SharedMemoryObject.h b/kernel/include/kernel/Memory/SharedMemoryObject.h
index 79dcb650..e494d949 100644
--- a/kernel/include/kernel/Memory/SharedMemoryObject.h
+++ b/kernel/include/kernel/Memory/SharedMemoryObject.h
@@ -14,7 +14,7 @@ namespace Kernel
 	class SharedMemoryObjectManager
 	{
 	public:
-		using Key = uint32_t;
+		using Key = size_t;
 
 	public:
 		static BAN::ErrorOr<void> initialize();
diff --git a/kernel/kernel/Memory/SharedMemoryObject.cpp b/kernel/kernel/Memory/SharedMemoryObject.cpp
index bd41b60c..c36893c7 100644
--- a/kernel/kernel/Memory/SharedMemoryObject.cpp
+++ b/kernel/kernel/Memory/SharedMemoryObject.cpp
@@ -32,9 +32,12 @@ namespace Kernel
 
 		LockGuard _(m_mutex);
 
-		Key key = Random::get<Key>();
+		// NOTE: don't set the top bit so cast to signed is not negative
+		auto generate_key = []() { return Random::get<Key>() & (~(Key)0 >> 1); };
+
+		Key key = generate_key();
 		while (m_objects.contains(key))
-			key = Random::get<Key>();
+			key = generate_key();
 
 		TRY(m_objects.insert(key, object));
 		return key;