From d2262b8f6d62cc6658574df9c12bdf99d9c8fc26 Mon Sep 17 00:00:00 2001
From: Itamar <itamar8910@gmail.com>
Date: Mon, 23 Nov 2020 22:38:29 +0200
Subject: [PATCH] UserspaceEmulator: Update memory protection of underlying
 pages

If a MmapRegion is file backed, we need to call mprotect on its
underlying pages.
---
 DevTools/UserspaceEmulator/MmapRegion.cpp | 10 ++++++++++
 DevTools/UserspaceEmulator/MmapRegion.h   |  7 +------
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/DevTools/UserspaceEmulator/MmapRegion.cpp b/DevTools/UserspaceEmulator/MmapRegion.cpp
index 40efc0f9a2..61f6b06f18 100644
--- a/DevTools/UserspaceEmulator/MmapRegion.cpp
+++ b/DevTools/UserspaceEmulator/MmapRegion.cpp
@@ -207,4 +207,14 @@ void MmapRegion::write64(u32 offset, ValueWithShadow<u64> value)
     *reinterpret_cast<u64*>(m_shadow_data + offset) = value.shadow();
 }
 
+void MmapRegion::set_prot(int prot)
+{
+    set_readable(prot & PROT_READ);
+    set_writable(prot & PROT_WRITE);
+    set_executable(prot & PROT_EXEC);
+    if (m_file_backed) {
+        mprotect(m_data, size(), prot);
+    }
+}
+
 }
diff --git a/DevTools/UserspaceEmulator/MmapRegion.h b/DevTools/UserspaceEmulator/MmapRegion.h
index 1e91fcbaac..68c1eb864e 100644
--- a/DevTools/UserspaceEmulator/MmapRegion.h
+++ b/DevTools/UserspaceEmulator/MmapRegion.h
@@ -56,12 +56,7 @@ public:
     bool is_malloc_block() const { return m_malloc; }
     void set_malloc(bool b) { m_malloc = b; }
 
-    void set_prot(int prot)
-    {
-        set_readable(prot & PROT_READ);
-        set_writable(prot & PROT_WRITE);
-        set_executable(prot & PROT_EXEC);
-    }
+    void set_prot(int prot);
 
     MallocRegionMetadata* malloc_metadata() { return m_malloc_metadata; }
     void set_malloc_metadata(Badge<MallocTracer>, NonnullOwnPtr<MallocRegionMetadata> metadata) { m_malloc_metadata = move(metadata); }