Re: [PATCH 2/2] x86/mmap: handle worst-case heap randomization in mmap_base

[Saidi, Ali]

ïOn 3/27/19, 2:52 PM, "linux-arm-kernel on behalf of Kees Cook" <linux-arm-kernel-bounces@xxxxxxxxxxxxxxxxxxx on behalf of keescook@xxxxxxxxxxxx> wrote:

    Adding some more people to CC... what do people think about this
    moving of the brk to ELF_ET_DYN_BASE in this corner-case? Anything
    that worked before should still work (i.e. the ultimately-launched
    binary already had the brk very far from its text, so this should be
    no different from a COMPAT_BRK standpoint). The only risk I see here
    is that if someone started to suddenly depend on the entire memory
    space above the mmap region being available when launching binaries
    via a direct loader execs... which seems highly unlikely, I'd hope:
    this would mean a binary would not work when execed normally.

Kees' proposal addresses the issue for me. Anyone have concerns on this proposed solution?

Ali