Messages in this thread | ![/](/images/icornerl.gif) | | From | Al Boldi <> | Subject | Re: [PATCH for 2.6.18-rc2] [2/8] i386/x86-64: Don't randomize stack top when no randomization personality | Date | Mon, 17 Jul 2006 14:24:49 +0300 |
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Ingo Molnar wrote: > * Andi Kleen <ak@suse.de> wrote: > > unsigned long arch_align_stack(unsigned long sp) > > { > > - if (randomize_va_space) > > + if (!(current->personality & ADDR_NO_RANDOMIZE) && > > randomize_va_space) sp -= get_random_int() % 8192; > > return sp & ~0xf; > > i'm not opposing this patch at all, but didnt the performance problems > go away when the 0xf was changed to 0x7f?
Yes, 0x7f is critical, but I'm not sure about side-effects.
> looks good otherwise.
except this one
> --- linux.orig/fs/binfmt_elf.c > +++ linux/fs/binfmt_elf.c > @@ -515,7 +515,8 @@ static unsigned long randomize_stack_top > { > unsigned int random_variable = 0; > > - if (current->flags & PF_RANDOMIZE) { > + if ((current->flags & PF_RANDOMIZE) && > + !(current->personality & ADDR_NO_RANDOMIZE)) { > random_variable = get_random_int() & STACK_RND_MASK; > random_variable <<= PAGE_SHIFT; > }
Why are you testing twice?
Thanks!
-- Al
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