Apple ARM binary codesign issue

Ken Cunningham ken.cunningham.webuse at gmail.com
Tue Sep 22 22:24:34 UTC 2020


On 2020-09-22, at 12:58 PM, Ryan Schmidt wrote:
> 
> To me it seems unrealistic for Apple to suggest that an infinite number of open source projects, many of whose developers have never seen a Mac, should now add code to their build systems to codesign things on macOS. Apple made a point of stating during WWDC that they love open source software; imposing busy work on the open source community is not a good way to show that love.

As I read it, the linker automatically codesigns the binary when you link, which is usually the final step in the process. So nobody has to change anything there.

But if you later modify that final linked binary by stripping it (I guess ) or changing the libraries around with install_name_tool (which I believe MESON does to every single install :>)  then you invalidate the signature, as you should IMHO.

I'm trying to imagine how Jeremy might prevent hackers from surreptitiously modifying signed binaries with strip or install_name_tool (which is good) while letting people modify signed binaries with strip or install_name_tool without invalidating the signature  -- I don't immediately see how you can have it both ways. But maybe Jeremy has some trick that works for this I can't think of. 

I won't be surprised if the solution is that you have to resign them after doing that, though.

Ken



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