From d4dd4a82bb3f487c628f005249858c54e42e5ce0 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Tue, 2 Feb 2021 20:16:13 +0100
Subject: [PATCH] Kernel: Don't allow sys$msyscall() on non-mmap regions

---
 Kernel/Syscalls/mmap.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Kernel/Syscalls/mmap.cpp b/Kernel/Syscalls/mmap.cpp
index 543c1b0189..eaf0f5c1b5 100644
--- a/Kernel/Syscalls/mmap.cpp
+++ b/Kernel/Syscalls/mmap.cpp
@@ -564,6 +564,9 @@ int Process::sys$msyscall(void* address)
     if (!region)
         return -EINVAL;
 
+    if (!region->is_mmap())
+        return -EINVAL;
+
     region->set_syscall_region(true);
     return 0;
 }