Messages in this thread | | | Date | Mon, 20 May 2013 16:19:41 +0200 | From | Florian Westphal <> | Subject | Re: [PATCH net-next] x86: bpf_jit_comp: secure bpf jit against spraying attacks |
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Eric Dumazet <eric.dumazet@gmail.com> wrote: > From: Eric Dumazet <edumazet@google.com> > > hpa bringed into my attention some security related issues > with BPF JIT on x86. > > This patch makes sure the bpf generated code is marked read only, > as other kernel text sections. > > It also splits the unused space (we vmalloc() and only use a fraction of > the page) in two parts, so that the generated bpf code not starts at a > known offset in the page, but a pseudo random one. > > Refs: > http://mainisusuallyafunction.blogspot.com/2012/11/attacking-hardened-linux-systems-with.html
What about emitting additional instructions at random locations in the generated code itself?
Eg., after every instruction, have random chance to insert 'xor $0xcc,%al; xor $0xcc,%al', etc?
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