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Fix: reduce AV false positives in runtime stubs #569

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Fix: reduce AV false positives in runtime stubs #569

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5 changes: 4 additions & 1 deletion Confuser.Protections/HardeningPhase.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -28,29 +28,32 @@
HardenMethod(context, module);
}

private static void HardenMethod(ConfuserContext context, ModuleDef module) {
var cctor = module.GlobalType.FindStaticConstructor();
if (cctor == null) {
context.Logger.Debug("No .cctor containing protection code found. Nothing to do.");
return;
}

if (!cctor.HasBody || !cctor.Body.HasInstructions) return;

var marker = context.Registry.GetService<IMarkerService>();
var instructions = cctor.Body.Instructions;
for (var i = instructions.Count - 1; i >= 0; i--) {
if (instructions[i].OpCode.Code != Code.Call) continue;
if (!(instructions[i].Operand is MethodDef targetMethod)) continue;
if (!targetMethod.IsStatic || targetMethod.DeclaringType != module.GlobalType) continue;
if (!marker.IsMarked(targetMethod) || !(marker.GetHelperParent(targetMethod) is Protection protection)) continue;

// Resource protection needs to rewrite the method during the write phase. Not compatible!
if (protection.FullId.Equals(ResourceProtection._FullId)) continue;
if (protection.FullId.Equals(ResourceProtection._FullId)) continue;

// Skip large methods to avoid aggregating suspicious patterns in .cctor
if (targetMethod.HasBody && targetMethod.Body.Instructions.Count > 150) continue;

cctor.Body.MergeCall(instructions[i]);
targetMethod.DeclaringType.Methods.Remove(targetMethod);
}
}
}

Check notice on line 58 in Confuser.Protections/HardeningPhase.cs

View check run for this annotation

codefactor.io / CodeFactor

Confuser.Protections/HardeningPhase.cs#L31-L58 

Complex Method
}
17 changes: 5 additions & 12 deletions Confuser.Runtime/Compressor.Compat.cs
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Original file line number Diff line number Diff line change
@@ -1,14 +1,13 @@
using System;
using System;
using System.IO;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Text;

namespace Confuser.Runtime {
internal static class CompressorCompat {
static byte[] key;

static GCHandle Decrypt(uint[] data, uint seed) {
static byte[] Decrypt(uint[] data, uint seed) {
var w = new uint[0x10];
var k = new uint[0x10];
ulong s = seed;
Expand All @@ -35,26 +34,23 @@ static GCHandle Decrypt(uint[] data, uint seed) {
byte[] j = Lzma.Decompress(b);
Array.Clear(b, 0, b.Length);

GCHandle g = GCHandle.Alloc(j, GCHandleType.Pinned);
var z = (uint)(s % 0x8a5cb7);
for (int i = 0; i < j.Length; i++) {
j[i] ^= (byte)s;
if ((i & 0xff) == 0)
s = (s * s) % 0x8a5cb7;
}
return g;
return j;
}

[STAThread]
static int Main(string[] args) {
var l = (uint)Mutation.KeyI0;
uint[] q = Mutation.Placeholder(new uint[Mutation.KeyI0]);

GCHandle h = Decrypt(q, (uint)Mutation.KeyI1);
var b = (byte[])h.Target;
byte[] b = Decrypt(q, (uint)Mutation.KeyI1);
Assembly a = Assembly.Load(b);
Array.Clear(b, 0, b.Length);
h.Free();
Array.Clear(q, 0, q.Length);

var m = typeof(CompressorCompat).Module;
Expand Down Expand Up @@ -93,12 +89,9 @@ static Assembly Resolve(object sender, ResolveEventArgs e) {
uint s = 0x6fff61;
foreach (byte c in b)
s = s * 0x5e3f1f + c;
GCHandle h = Decrypt(d, s);

var f = (byte[])h.Target;
byte[] f = Decrypt(d, s);
Assembly a = Assembly.Load(f);
Array.Clear(f, 0, f.Length);
h.Free();
Array.Clear(d, 0, d.Length);

return a;
Expand Down
17 changes: 5 additions & 12 deletions Confuser.Runtime/Compressor.cs
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Original file line number Diff line number Diff line change
@@ -1,14 +1,13 @@
using System;
using System;
using System.IO;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Text;

namespace Confuser.Runtime {
internal static class Compressor {
static byte[] key;

static GCHandle Decrypt(uint[] data, uint seed) {
static byte[] Decrypt(uint[] data, uint seed) {
var w = new uint[0x10];
var k = new uint[0x10];
ulong s = seed;
Expand All @@ -35,14 +34,13 @@ static GCHandle Decrypt(uint[] data, uint seed) {
byte[] j = Lzma.Decompress(b);
Array.Clear(b, 0, b.Length);

GCHandle g = GCHandle.Alloc(j, GCHandleType.Pinned);
var z = (uint)(s % 0x8a5cb7);
for (int i = 0; i < j.Length; i++) {
j[i] ^= (byte)s;
if ((i & 0xff) == 0)
s = (s * s) % 0x8a5cb7;
}
return g;
return j;
}

[STAThread]
Expand All @@ -52,12 +50,10 @@ static int Main(string[] args) {

Assembly a = Assembly.GetExecutingAssembly();
Module n = a.ManifestModule;
GCHandle h = Decrypt(q, (uint)Mutation.KeyI1);
var b = (byte[])h.Target;
byte[] b = Decrypt(q, (uint)Mutation.KeyI1);
Module m = a.LoadModule("koi", b);

Array.Clear(b, 0, b.Length);
h.Free();
Array.Clear(q, 0, q.Length);

key = n.ResolveSignature(Mutation.KeyI2);
Expand Down Expand Up @@ -98,12 +94,9 @@ static Assembly Resolve(object sender, ResolveEventArgs e) {
uint s = 0x6fff61;
foreach (byte c in b)
s = s * 0x5e3f1f + c;
GCHandle h = Decrypt(d, s);

var f = (byte[])h.Target;
byte[] f = Decrypt(d, s);
Assembly a = Assembly.Load(f);
Array.Clear(f, 0, f.Length);
h.Free();
Array.Clear(d, 0, d.Length);

return a;
Expand Down