Update code to handle another case
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@ -42,6 +42,8 @@ namespace de4dot.blocks.cflow {
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changed |= deobfuscateLdloc(switchBlock);
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else if (isStLdlocBranch(switchBlock, true))
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changed |= deobfuscateStLdloc(switchBlock);
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else if (isSwitchType1(switchBlock))
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changed |= deobfuscateType1(switchBlock);
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}
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return changed;
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}
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@ -55,6 +57,10 @@ namespace de4dot.blocks.cflow {
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return switchBlock.Instructions.Count == numInstrs && switchBlock.Instructions[0].isLdloc();
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}
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static bool isSwitchType1(Block switchBlock) {
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return switchBlock.FirstInstr.isLdloc();
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}
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bool isStLdlocBranch(Block switchBlock, bool isSwitch) {
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int numInstrs = 2 + (isSwitch ? 1 : 0);
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return switchBlock.Instructions.Count == numInstrs &&
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@ -218,6 +224,60 @@ namespace de4dot.blocks.cflow {
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}
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}
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bool deobfuscateType1(Block switchBlock) {
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Block target;
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if (!emulateGetTarget(switchBlock, out target) || target != null)
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return false;
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bool changed = false;
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foreach (var source in new List<Block>(switchBlock.Sources)) {
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if (!source.canAppend(switchBlock))
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continue;
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if (!willHaveKnownTarget(switchBlock, source))
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continue;
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source.append(switchBlock);
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changed = true;
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}
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return changed;
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}
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bool emulateGetTarget(Block switchBlock, out Block target) {
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instructionEmulator.init(blocks.Method.HasThis, false, blocks.Method.Parameters, blocks.Locals);
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try {
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instructionEmulator.emulate(switchBlock.Instructions, 0, switchBlock.Instructions.Count - 1);
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}
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catch (System.NullReferenceException) {
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// Here if eg. invalid metadata token in a call instruction (operand is null)
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target = null;
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return false;
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}
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target = getTarget(switchBlock);
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return true;
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}
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bool willHaveKnownTarget(Block switchBlock, Block source) {
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instructionEmulator.init(blocks.Method.HasThis, false, blocks.Method.Parameters, blocks.Locals);
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try {
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instructionEmulator.emulate(source.Instructions);
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instructionEmulator.emulate(switchBlock.Instructions, 0, switchBlock.Instructions.Count - 1);
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}
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catch (System.NullReferenceException) {
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// Here if eg. invalid metadata token in a call instruction (operand is null)
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return false;
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}
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return getTarget(switchBlock) != null;
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}
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Block getTarget(Block switchBlock) {
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var val1 = instructionEmulator.pop();
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if (!val1.isInt32())
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return null;
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return CflowUtils.getSwitchTarget(switchBlock.Targets, switchBlock.FallThrough, (Int32Value)val1);
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}
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Block getSwitchTarget(IList<Block> targets, Block fallThrough, Block source, Value value) {
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if (!value.isInt32())
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return null;
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