How do I get swift binaries to work suid?

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Created Jul ’15

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Hi All,

I am attempting to implement a "restricted binary" (i.e. suid program) in swift. The issue that I have not found a way around is that all swift applications bundle the swift runtime with them and "restricted binaries" are blocked by dyld from loading dylibs using @rpath or @executable or @loader_path.

dyld: warning, LC_RPATH @executable_path/../Frameworks in /Users/USER/TestApp.app/Contents/MacOS/TestApp being ignored in restricted program because of @executable_path
dyld: Library not loaded: @rpath/libswiftAppKit.dylib
  Referenced from: /Users/USER/TestApp.app/Contents/MacOS/TestApp
  Reason: image not found

Xcode 6.4 generates swift binaries that reference the swift runtime via RPATH (i.e. rpath = @executable/../Frameworks and @rpath/libswiftAppKit.dylib) and I have tried using install_name_tool to change these references to @executable or @loader_path but it appears that all of the "@" paths are blocked by dyld.

Dyld Error Message:
  Library not loaded: @loader_path/../Frameworks/libswiftAppKit.dylib
  Referenced from: /Users/USER/TestApp.app/Contents/MacOS/TestApp
  Reason: unsafe use of @loader_path in /Users/USER/TestApp.app/Contents/MacOS/TestApp with restricted binary

Any ideas on how to use swift? Or do I have to just use Objective-C?

Thanks,

CraigN

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Answer 1

DTS Engineer OP

Apple

Jul ’15

I am attempting to implement a "restricted binary" (i.e. suid program) in swift.

Why?

setuid binaries are prone to security vulnerabilities and we recommend that you avoid them on current systems.

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