Messages in this thread | | | Subject | Re: [PATCH v2,net-next 1/2] ip_gre: fix parsing gre header in ipgre_err | From | Haishuang Yan <> | Date | Sat, 15 Sep 2018 09:22:19 +0800 |
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> On 2018年9月14日, at 下午8:44, Edward Cree <ecree@solarflare.com> wrote: > > On 13/09/18 18:58, David Miller wrote: >> From: Haishuang Yan <yanhaishuang@cmss.chinamobile.com> >> Date: Wed, 12 Sep 2018 17:21:21 +0800 >> >>> @@ -86,7 +86,7 @@ int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi, >>> >>> options = (__be32 *)(greh + 1); >>> if (greh->flags & GRE_CSUM) { >>> - if (skb_checksum_simple_validate(skb)) { >>> + if (csum_err && skb_checksum_simple_validate(skb)) { >>> *csum_err = true; >>> return -EINVAL; >>> } >> You want to ignore csum errors, but you do not want to elide the side >> effects of the skb_checksum_simple_validate() call which are to set >> skb->csum_valid and skb->csum. >> >> Therefore, the skb_checksum_simple_validate() call still needs to be >> performed. We just wont return -EINVAL in the NULL csum_err case. > > How about just reversing the order of the AND? > > if (skb_checksum_simple_validate(skb) && csum_err) { > *csum_err = true; > return -EINVAL; > } > >
It looks good to me, thanks!
But skb_checksum_try_convert only need to be called after the checksum is validated, so I suggested a better solution as following:
89 if (!skb_checksum_simple_validate(skb)) { 90 skb_checksum_try_convert(skb, IPPROTO_GRE, 0, 91 null_compute_pseudo); 92 } else if (csum_err) { 93 *csum_err = true; 94 return -EINVAL; 95 }
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