Messages in this thread | | | Date | Thu, 04 Apr 2013 13:27:57 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 3/3] x86: kernel base offset ASLR |
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On 04/04/2013 01:23 PM, Julien Tinnes wrote: > On Thu, Apr 4, 2013 at 1:19 PM, Julien Tinnes <jln@google.com> wrote: >> On Thu, Apr 4, 2013 at 1:12 PM, H. Peter Anvin <hpa@zytor.com> wrote: >>> On 04/04/2013 01:07 PM, Kees Cook wrote: >>>> However, the benefits of >>>> this feature in certain environments exceed the perceived weaknesses[2]. >>> >>> Could you clarify? >> >> I think privilege reduction in general, and sandboxing in particular, >> can make KASLR even more useful. A lot of the information leaks can be >> mitigated in the same way as attack surface and vulnerabilities can be >> mitigated. > > Case in point: > - leaks of 64 bits kernel values to userland in compatibility > sub-mode. Sandboxing by using seccomp-bpf can restrict a process to > the 64-bit mode API. > - restricting access to the syslog() system call >
That doesn't really speak to the value proposition. My concern is that we're going to spend a lot of time chasing/plugging infoleaks instead of tackling bigger problems.
8 bits of entropy is not a lot.
-hpa
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