ASLR --high-entropy-va on x64

[kmedcalf]

When you build can you enable ASLR High-Entropy-VA? I believe this needs an additional linker flag to be set (it does with GCC) and you also have to base the image above the 4 Gig line? These can be set after the fact by rebasing the images and setting the appropriate header flags, but unless the code is incompatible with high-entropy-va (which it does not appear to be) can this become the default?

[mhammond]

I'll happily look at a PR request for this, but I doubt I'm going to find the time to research it myself.

[kmedcalf]

All I had to change in the already compiled binaries (the .pyd) for x64 (AMD64) was to run EDITBIN /REBASE:BASE=0x200000000 against them, so I suspect that all the settings in the compiler are correct and the base address just needs to be changed. In GCC (MinGW-W64) I use -Wl,--nxcompat,--dynamicbase,--high-entropy-va,--image-base=0x200000000. I presume for the Microsoft compilers the options to enable NX COMPATIBILITY, DYNAMICBASE, and HIGH ENTROPY are also the default.

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