On Wed 08-08-18 10:16:01, Vlastimil Babka wrote: > On 08/07/2018 09:54 PM, Michal Hocko wrote: > > From: Michal Hocko <[email protected]> > > > > eacd86ca3b03 ("net/netfilter/x_tables.c: use kvmalloc() > > in xt_alloc_table_info()") has unintentionally fortified > > xt_alloc_table_info allocation when __GFP_RETRY has been dropped from > > the vmalloc fallback. Later on there was a syzbot report that this > > can lead to OOM killer invocations when tables are too large and > > 0537250fdc6c ("netfilter: x_tables: make allocation less aggressive") > > has been merged to restore the original behavior. Georgi Nikolov however > > noticed that he is not able to install his iptables anymore so this can > > be seen as a regression. > > > > The primary argument for 0537250fdc6c was that this allocation path > > shouldn't really trigger the OOM killer and kill innocent tasks. On the > > other hand the interface requires root and as such should allow what the > > admin asks for. Root inside a namespaces makes this more complicated > > because those might be not trusted in general. If they are not then such > > namespaces should be restricted anyway. Therefore drop the __GFP_NORETRY > > and replace it by __GFP_ACCOUNT to enfore memcg constrains on it. > > > > Fixes: 0537250fdc6c ("netfilter: x_tables: make allocation less aggressive") > > Reported-by: Georgi Nikolov <[email protected]> > > Suggested-by: Vlastimil Babka <[email protected]> > > Acked-by: Florian Westphal <[email protected]> > > Signed-off-by: Michal Hocko <[email protected]> > > Acked-by: Vlastimil Babka <[email protected]>
Thanks! > IIRC According to Florian there are more places like this in the > netfilter code? Well, this is more for netfilter guys. I can only give a general guidance that generally untrusted allocations triggered from userspace should be a subject of kmem accounting. -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
