Take the compiler and run with it: a quick story of Swift obfuscator

Imagine a group of people with no background in the compilers nor C++.
Imagine them coming across a wonderful open source project, such as the Swift compiler.
What could happen if they started playing with it? Hacking, adding changes left and right, taking parts and making them work the way they were never intended?
Surely, the output would be some gibberish without meaning!
This story really happened. Come to listen how and why. Sometimes the gibberish is exactly what you need.

Transcript

1. Take the compiler
   and run with it
   A quick story of Swift obfuscator
   Krzysztof Siejkowski, @_siejkowski
   

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3. In software development,
   obfuscation is the deliberate act of
   creating source or machine code that
   is difficult for humans to understand
   — Wikipedia
   

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8. @objc
   NSObject
   

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10. Source
    code
    Binary
    Compilation
    Attacker
    Obfuscation
    

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11. Source
    code
    Obfuscated
    binary
    Compilation
    Attacker
    Obfuscation
    Example: iXGuard by GuardSquare
    

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12. Source
    code
    Obfuscated

    binary
    Obfuscating

    Compilation
    Attacker
    Obfuscation
    Example: Obfuscator-LLVM
    

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13. Obfuscated
    source
    code
    Obfuscated
    binary
    Compilation
    Attacker
    Obfuscation
    Example: ???
    

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16. Obfuscated
    source
    code
    Obfuscated
    binary
    Compilation
    Attacker
    Obfuscation
    Example: WE
    

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17. Source
    code
    Parse
    Find symbols
    Analyze symbols
    Obfuscated
    source
    code
    Rename
    

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18. Compiler ✨
    

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25. Swift compiler 

    as a library?
    

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26. swiftParse
    swiftDriver
    swiftAST
    swiftSyntax
    swiftBasic
    

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27. swiftParse
    swiftDriver
    swiftAST
    swiftSyntax
    swiftBasic
    

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28. swiftParse
    swiftDriver
    swiftAST
    swiftSyntax
    swiftBasic
    swift
    swift-syntax-
    test
    swift-refactor
    

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29. swiftParse
    swiftDriver
    swiftAST
    swiftSyntax
    swiftBasic
    swift
    swift-syntax-
    test
    swift-refactor
    

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30. swiftParse
    swiftDriver
    swiftAST
    swiftSyntax
    swiftBasic
    swiftObfuscation
    obfuscator-renamer
    obfuscator-symbol-
    extractor
    

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33. Source code
    MAGIC

    %
    Analyzed 

    source code
    

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34. swiftFrontend
    Source code
    CompilerInstance.
    performSema()
    Analyzed 

    source code
    

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36. swiftAST
    Analyzed 

    source code
    SourceFileWalker
    Symbols

    with locations
    

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37. Symbols 

    with locations
    MAGIC
    %
    Obfuscated
    source files
    

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38. swiftIDE
    Symbols 

    with locations
    SourceEngine &
    SourceManager
    Obfuscated
    source files
    

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41. Supports Not supports
    

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42. Supports Not supports
    DSYM file generation
    Multiple targets
    Some exotic Swift constructs
    

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43. Supports Not supports
    Renames in Storyboards and XIBs DSYM file generation
    Excluding configuration Multiple targets
    Simple integration (local & CI) Some exotic Swift constructs
    

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44. Open source
    github.com/Polidea/SiriusObfuscator
    

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46. Pros Cons
    Anything compiler can do, 

    you can do too!
    

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47. Pros Cons
    Anything compiler can do, 

    you can do too!
    No stable API, 

    breaking changes any time
    

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48. Pros Cons
    Anything compiler can do, 

    you can do too!
    No stable API, 

    breaking changes any time
    So many tools available!
    

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49. Pros Cons
    Anything compiler can do, 

    you can do too!
    No stable API, 

    breaking changes any time
    So many tools available!
    Compiler libs are designed for
    compilation, not for your needs
    

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50. Pros Cons
    Anything compiler can do, 

    you can do too!
    No stable API, 

    breaking changes any time
    So many tools available!
    Compiler libs are designed for
    compilation, not for your needs
    Support for both 

    Swift and Objective-C
    

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51. Pros Cons
    Anything compiler can do, 

    you can do too!
    No stable API, 

    breaking changes any time
    So many tools available!
    Compiler libs are designed for
    compilation, not for your needs
    Support for both 

    Swift and Objective-C
    Might be too much to support
    

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52. Alternatives
    • libSyntax
    • SourceKit
    • existing swift tools
    

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54. github.com/Polidea/SiriusObfuscator
    Documentation
    

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55. 
    @KacperHarasim
    

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56. Thank you!
    @_siejkowski
    

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