Messages in this thread | | | Date | Thu, 27 Mar 2014 16:01:01 +0000 | From | Patrick McHardy <> | Subject | Re: [PATCH] netfilter: nf_conntrack: reserve two bytes for nf_ct_ext->len |
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On Thu, Mar 27, 2014 at 04:50:33PM +0100, Florian Westphal wrote: > Andrey Vagin <avagin@openvz.org> wrote: > > "len" contains sizeof(nf_ct_ext) and size of extensions. In a worst > > case it can contain all extensions. Bellow you can find sizes for all > > types of extensions. Their sum is definitely bigger than 256. > > > > nf_ct_ext_types[0]->len = 24 > > nf_ct_ext_types[1]->len = 32 > > nf_ct_ext_types[2]->len = 24 > > nf_ct_ext_types[3]->len = 32 > > nf_ct_ext_types[4]->len = 152 > > Guess its the timer in the ecache extension (with LOCKDEP on probably). > > I'll submit a patch to get rid of that shortly. > > I think your patch is fine because the 'no timer > in ecache extension' change is quite large, needs review/stress testing > etc and is inapropriate for stable tree anyway. > > > I have seen "len" up to 280 and my host has crashes w/o this patch. > > ecache is 24 bytes without that timer, should be < 256 in total for > all extensions. > > I think BUILD_BUG_ON test would be nice.
We also have variable length extensions, but we definitely should catch this *somewhere*.
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