#1324 P-code deobfuscation may yield incorrect decompilation(++ operator side effect overlooked)

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List of issues

Author:

vonchun

Date created: 12/20/2016, 5:53:28 am

Type: bug

Visibility: Everybody

Assigned to:

Labels: Decompilation Obfuscated

State: closed Help

> What steps will reproduce the problem? 1. use hex2bin to convert the attached txt file to binary file. 2. use P-code deobufscation deobfuscate it 3. decompile it > What is the expected output? What do you see instead? the last line of this function param1[_loc7_++] = param1[_loc7_++] ^ _loc3_[_loc6_ + _loc3_[_loc4_] & class_1.method_1(1313413342,1313413153)]; Here _loc7++ occurs twice in this line, i.e. incremented twice - actually it should only increment once. It should be decompiled as: param1[_loc7_] = param1[_loc7_] ^ _loc3_[_loc6_ + _loc3_[_loc4_] & class_1.method_1(1313413342,1313413153)]; _loc7_++ > What version of the product are you using? Is it "nightly build"? Which operating system do you have? > Please provide any additional information below. If the problem is related to a SWF file, attach it here, otherwise we can't help you.

hex.txt (4 KiB)

JPEXS

02/08/2021, 11:12:02 am

I don't know whether it's still related as flash is gone, I can't properly check it as I don't have a SWF file with apropriate multinames. But I think this is fixed in current nightly (1784). I made few changes regarding dup instruction. I am closing this issue.

State: new→closed