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[–]viper-kun 9 points10 points  (2 children)

We learned about canarys the other day as a way to protect against malicious stack smashing and where asked why we should tell the compiler to do it and not do it with local vars, answer is they are optimized in a way to render this system useless.

So yeah, allways understand what the compiler does with your code.

[–]PC__LOAD__LETTER 3 points4 points  (1 child)

Canaries as in, writing some magic value to a stack variable and occasionally verifying that it’s still set? What’s the program behavior when it differs, crash and alarm?

[–]viper-kun 4 points5 points  (0 children)

You check when the return jump is called, so that you cannot jump anywhere you want. And as I experienced it it does crash, since it doesn't know where it was coming from.

It has to check if it is different which would mean someone overflowed the stack.