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Re: Offset2lib: bypassing full ASLR on 64bit Linux


From: Daniel Micay <danielmicay () gmail com>
Date: Wed, 10 Dec 2014 13:51:12 -0500

On 10/12/14 01:20 PM, Daniel Micay wrote:

I expect that the same thing can be caused by making aligned
allocations. If you make a 4M naturally aligned allocation via an API
like posix_memalign, the allocator will probably mmap 4M + the maximum
excess. If it unmaps the excess memory at the head/tail, then it will
have wiped out 10 bits of entropy for future mmap allocations because
the tail will always be at a 4M boundary.

(ofc this isn't limited to mmap, but it's a simple example)

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