Messages in this thread | | | Date | Thu, 22 Apr 2021 22:03:05 +0100 | From | Phillip Potter <> | Subject | Re: [PATCH] net: geneve: modify IP header check in geneve6_xmit_skb |
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On Thu, Apr 22, 2021 at 07:18:49PM +0200, Sabrina Dubroca wrote: > 2021-04-22, 18:52:10 +0200, Eric Dumazet wrote: > > On Thu, Apr 22, 2021 at 6:04 PM Sabrina Dubroca <sd@queasysnail.net> wrote: > > > > > > 2021-04-22, 02:39:42 +0200, Florian Westphal wrote: > > > > Phillip Potter <phil@philpotter.co.uk> wrote: > > > > > Modify the check in geneve6_xmit_skb to use the size of a struct iphdr > > > > > rather than struct ipv6hdr. This fixes two kernel selftest failures > > > > > introduced by commit 6628ddfec758 > > > > > ("net: geneve: check skb is large enough for IPv4/IPv6 header"), without > > > > > diminishing the fix provided by that commit. > > > > > > > > What errors? > > > > > > > > > Reported-by: kernel test robot <oliver.sang@intel.com> > > > > > Signed-off-by: Phillip Potter <phil@philpotter.co.uk> > > > > > --- > > > > > drivers/net/geneve.c | 2 +- > > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > > > diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c > > > > > index 42f31c681846..a57a5e6f614f 100644 > > > > > --- a/drivers/net/geneve.c > > > > > +++ b/drivers/net/geneve.c > > > > > @@ -988,7 +988,7 @@ static int geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev, > > > > > __be16 sport; > > > > > int err; > > > > > > > > > > - if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr))) > > > > > + if (!pskb_network_may_pull(skb, sizeof(struct iphdr))) > > > > > return -EINVAL; > > > > > > > > Seems this is papering over some bug, this change makes no sense to > > > > me. Can you please explain this? > > > > > > I'm not sure the original commit (6628ddfec758 ("net: geneve: check > > > skb is large enough for IPv4/IPv6 header")) is correct either. GENEVE > > > isn't limited to carrying IP, I think an ethernet header with not much > > > else on top should be valid. > > > > Maybe, but we still attempt to use ip_hdr() in this case, from > > geneve_get_v6_dst() > > > > So there is something fishy. > > In ip_tunnel_get_dsfield()? Only if there's IP in the packet. Other > tunnel types (except vxlan, which probably has the same problem as > geneve) ues pskb_inet_may_pull, that looks like what we need here as > well. > > -- > Sabrina >
Dear Sabrina,
Thank you for your feedback. I will try and rework the patch to fix my original commit using the technique you suggest.
Regards, Phil
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