Messages in this thread | | | Date | Thu, 25 Oct 2007 07:13:24 -0700 | From | Arjan van de Ven <> | Subject | Re: x86: randomize brk() and RLIMIT_DATA |
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On Thu, 25 Oct 2007 16:41:24 +0300 Sami Farin <safari-kernel@safari.iki.fi> wrote:
> Would be neat if randomized brk and setrlimit(RLIMIT_DATA, ...) > worked in a predictable way:
this isn't a valid case afaics; even on "traditional x86" (before we changed the address space layout, or even today if you have an unlimited stack rlimit) this isn't going to work. applications really shouldn't use (s)brk() but malloc(); you have to be able to fall back to mmap regardless of what you do.
> > $ gcc brk.c -fPIC -pie -m64;./a.out;./a.out;./a.out > sbrk=0x7f721b815000 main=0x7f721af04860 > sbrk succeeded (brk=0x7f721b909240) > sbrk=0x7fc3d77e2000 main=0x7fc3d66fa860 > sbrk failed: Cannot allocate memory (brk=0x7fc3d77e2000) > sbrk=0x7f05b0615000 main=0x7f05af76b860 > sbrk failed: Cannot allocate memory (brk=0x7f05b0615000) >
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