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SubjectRe: [PATCH 2/2] x86/mmap: handle worst-case heap randomization in mmap_base
On Tue, 12 Mar 2019, Ali Saidi wrote:

> Increase mmap_base by the worst-case brk randomization so that
> the stack and heap remain apart.
> In Linux 4.13 a change was committed that special cased the kernel ELF
> loader when the loader is invoked directly (eab09532d400; binfmt_elf: use
> ELF_ET_DYN_BASE only for PIE). Generally, the loader isn’t invoked
> directly and this issue is limited to cases where it is, (e.g to set a
> non-inheritable LD_LIBRARY_PATH, testing new versions of the loader). In
> those rare cases, the loader doesn't take into account the amount of brk
> randomization that will be applied by arch_randomize_brk(). This can
> lead to the stack and heap being arbitrarily close to each other.

That explains not why you need this change. What's the consequence of them
being close to each other?


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