From patchwork Tue Jul 12 17:58:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrea Mayer X-Patchwork-Id: 12915360 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D4ACAC43334 for ; Tue, 12 Jul 2022 18:00:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233507AbiGLSAL (ORCPT ); Tue, 12 Jul 2022 14:00:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58190 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233459AbiGLSAG (ORCPT ); Tue, 12 Jul 2022 14:00:06 -0400 Received: from smtp.uniroma2.it (smtp.uniroma2.it [160.80.6.16]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7EA63B79F9; Tue, 12 Jul 2022 11:00:01 -0700 (PDT) Received: from localhost.localdomain ([160.80.103.126]) by smtp-2015.uniroma2.it (8.14.4/8.14.4/Debian-8) with ESMTP id 26CHxCBs005871 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Tue, 12 Jul 2022 19:59:14 +0200 From: Andrea Mayer To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Hideaki YOSHIFUJI , David Ahern , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , David Lebrun , Mathieu Xhonneux , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org Cc: Stefano Salsano , Paolo Lungaroni , Ahmed Abdelsalam , Anton Makarov , Andrea Mayer Subject: [net 1/3] seg6: fix skb checksum evaluation in SRH encapsulation/insertion Date: Tue, 12 Jul 2022 19:58:35 +0200 Message-Id: <20220712175837.16267-2-andrea.mayer@uniroma2.it> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20220712175837.16267-1-andrea.mayer@uniroma2.it> References: <20220712175837.16267-1-andrea.mayer@uniroma2.it> MIME-Version: 1.0 X-Virus-Scanned: clamav-milter 0.100.0 at smtp-2015 X-Virus-Status: Clean Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Support for SRH encapsulation and insertion was introduced with commit 6c8702c60b88 ("ipv6: sr: add support for SRH encapsulation and injection with lwtunnels"), through the seg6_do_srh_encap() and seg6_do_srh_inline() functions, respectively. The former encapsulates the packet in an outer IPv6 header along with the SRH, while the latter inserts the SRH between the IPv6 header and the payload. Then, the headers are initialized/updated according to the operating mode (i.e., encap/inline). Finally, the skb checksum is calculated to reflect the changes applied to the headers. The IPv6 payload length ('payload_len') is not initialized within seg6_do_srh_{inline,encap}() but is deferred in seg6_do_srh(), i.e. the caller of seg6_do_srh_{inline,encap}(). However, this operation invalidates the skb checksum, since the 'payload_len' is updated only after the checksum is evaluated. To solve this issue, the initialization of the IPv6 payload length is moved from seg6_do_srh() directly into the seg6_do_srh_{inline,encap}() functions and before the skb checksum update takes place. Fixes: 6c8702c60b88 ("ipv6: sr: add support for SRH encapsulation and injection with lwtunnels") Reported-by: Paolo Abeni Link: https://lore.kernel.org/all/20220705190727.69d532417be7438b15404ee1@uniroma2.it Signed-off-by: Andrea Mayer --- net/ipv6/seg6_iptunnel.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c index d64855010948..e756ba705fd9 100644 --- a/net/ipv6/seg6_iptunnel.c +++ b/net/ipv6/seg6_iptunnel.c @@ -189,6 +189,8 @@ int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto) } #endif + hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); + skb_postpush_rcsum(skb, hdr, tot_len); return 0; @@ -241,6 +243,8 @@ int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh) } #endif + hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); + skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen); return 0; @@ -302,7 +306,6 @@ static int seg6_do_srh(struct sk_buff *skb) break; } - ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); skb_set_transport_header(skb, sizeof(struct ipv6hdr)); nf_reset_ct(skb);