Messages in this thread | | | Date | Tue, 31 May 2011 18:43:16 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH v4 09/10] x86-64: Randomize int 0xcc magic al values at boot |
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* Andrew Lutomirski <luto@mit.edu> wrote:
> On Tue, May 31, 2011 at 11:56 AM, Andrew Lutomirski <luto@mit.edu> wrote: > > We could scrap int 0xcc entirely and emulate on page fault, but that > > is slower and has other problems (like breaking anything that thinks > > it can look at a call target in a binary and dereference that > > address). > > > > Here's a possibly dumb/evil idea: > > > > Put real syscalls in the vsyscall page but mark the page NX. Then > > emulate the vsyscalls on the PF_INSTR fault when userspace jumps to > > the correct address but send SIGSEGV for the wrong address. > > > > Down side: it's even more complexity for the same silly case. > > Scratch that. It's incompatible with keeping time() fast for now.
If we can find another fault than #PF then it will be similarly fast to an INT $0xCC so please at least investigate this route.
Thanks,
Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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