Messages in this thread |  | | Subject | Re: [PATCH net] bpf: fix bug in eBPF verifier | From | Hannes Frederic Sowa <> | Date | Tue, 21 Oct 2014 12:35:42 +0200 |
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On Mo, 2014-10-20 at 14:54 -0700, Alexei Starovoitov wrote: > while comparing for verifier state equivalency the comparison > was missing a check for uninitialized register. > Make sure it does so and add a testcase. > > Fixes: f1bca824dabb ("bpf: add search pruning optimization to verifier") > Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> > Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> > --- > > while we were staring at the verifier code with Hannes during LPC > something felt odd in this spot. Yes. It was a bug. Fix it. > > kernel/bpf/verifier.c | 3 ++- > samples/bpf/test_verifier.c | 11 +++++++++++ > 2 files changed, 13 insertions(+), 1 deletion(-) > > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > index 801f5f3..9f81818 100644 > --- a/kernel/bpf/verifier.c > +++ b/kernel/bpf/verifier.c > @@ -1409,7 +1409,8 @@ static bool states_equal(struct verifier_state *old, struct verifier_state *cur) > if (memcmp(&old->regs[i], &cur->regs[i], > sizeof(old->regs[0])) != 0) { > if (old->regs[i].type == NOT_INIT || > - old->regs[i].type == UNKNOWN_VALUE) > + (old->regs[i].type == UNKNOWN_VALUE && > + cur->regs[i].type != NOT_INIT)) > continue; > return false; > }
That makes sense.
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Thanks, Hannes
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