Added ptrguard to be used whenever ptrs are being used.

2026-01-20 00:24:42 +01:00
parent 367af2c3d0
commit cff866dcc2
4 changed files with 183 additions and 106 deletions
--- a/LightlessSync/Utils/PtrGuard.cs
+++ b/LightlessSync/Utils/PtrGuard.cs
@@ -0,0 +1,55 @@
+using System.Runtime.InteropServices;
+using static LightlessSync.Utils.PtrGuardMemory;
+
+namespace LightlessSync.Utils
+{
+    public static partial class PtrGuard
+    {
+        private const ulong _minLikelyPtr = 0x0000_0001_0000_0000UL;
+        private const ulong _maxUserPtr = 0x0000_7FFF_FFFF_FFFFUL;
+        private const ulong _aligmentPtr = 0x7UL;
+
+        public static bool LooksLikePtr(nint p)
+        {
+            if (p == 0) return false;
+            var u = (ulong)p;
+            if (u < _minLikelyPtr) return false;
+            if (u > _maxUserPtr) return false;
+            if ((u & _aligmentPtr) != 0) return false;
+            return true;
+        }
+        public static bool TryReadIntPtr(nint addr, out nint value)
+        {
+            value = 0;
+            
+            if (!LooksLikePtr(addr))
+                return false;
+
+            return ReadProcessMemory(GetCurrentProcess(), addr, out value, (nuint)IntPtr.Size, out nuint bytesRead)
+                   && bytesRead == (nuint)IntPtr.Size;
+        }
+
+        public static bool IsReadable(nint addr, nuint size)
+        {
+            if (addr == 0 || size == 0) return false;
+
+            if (VirtualQuery(addr, out var mbi, (nuint)Marshal.SizeOf<MEMORY_BASIC_INFORMATION>()) == 0)
+                return false;
+
+            const uint Commit = 0x1000;
+            const uint NoAccess = 0x01;
+            const uint PageGuard = 0x100;
+
+            if (mbi.State != Commit) return false;
+            if ((mbi.Protect & PageGuard) != 0) return false;
+            if (mbi.Protect == NoAccess) return false;
+
+            ulong start = (ulong)addr;
+            ulong end = start + size - 1;
+            ulong r0 = (ulong)mbi.BaseAddress;
+            ulong r1 = r0 + mbi.RegionSize - 1;
+
+            return start >= r0 && end <= r1;
+        }
+    }
+}
--- a/LightlessSync/Utils/PtrGuardMemory.cs
+++ b/LightlessSync/Utils/PtrGuardMemory.cs
@@ -0,0 +1,36 @@
+using System.Runtime.InteropServices;
+
+namespace LightlessSync.Utils
+{
+    internal static class PtrGuardMemory
+    {
+        [StructLayout(LayoutKind.Sequential)]
+        internal struct MEMORY_BASIC_INFORMATION
+        {
+            public nint BaseAddress;
+            public nint AllocationBase;
+            public uint AllocationProtect;
+            public nuint RegionSize;
+            public uint State;
+            public uint Protect;
+            public uint Type;
+        }
+
+        [DllImport("kernel32.dll", SetLastError = true)]
+        internal static extern nuint VirtualQuery(
+            nint lpAddress,
+            out MEMORY_BASIC_INFORMATION lpBuffer,
+            nuint dwLength);
+
+        [DllImport("kernel32.dll", SetLastError = true)]
+        internal static extern bool ReadProcessMemory(
+            nint hProcess,
+            nint lpBaseAddress,
+            out nint lpBuffer,
+            nuint nSize,
+            out nuint lpNumberOfBytesRead);
+
+        [DllImport("kernel32.dll")]
+        internal static extern nint GetCurrentProcess();
+    }
+}