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It was the first thing that popped into my mind at first too but then I started thinking about it and out of the top of my head the only issue I could think of would be if symbols are stripped (you can't "load them from another kernel"). But as long as they're in there I think there shouldn't be any problems? But please elaborate on what you mean with the "deal with" part.

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Wouldn't the symbols being there defeat the purpose of the whole randomization thing?

The purpose is to defeat a generic exploit.

For example, with ASLR, it's easy to retrieve the current layout of the processus and therefore to debug it (if you have the appropriate symbols) despite the randomization. But an exploit has to be built for the specific instance of the application running. If you share the same privileges as the process, you can get the current mapping but an exploit is useless. If you don't, you don't have access to the mapping either and it's difficult to get it while you are executing code inside the process as you can't easily access the functions you would need for that.

Binutils has had debuglink support for, like, a decade now. OpenBSD uses it to put the symbols in a separate file. gdb knows how to find it using information in the executable.

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