From: Andrea Mayer andrea.mayer@uniroma2.it
[ Upstream commit df8386d13ea280d55beee1b95f61a59234a3798b ]
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 pabeni@redhat.com Link: https://lore.kernel.org/all/20220705190727.69d532417be7438b15404ee1@uniroma2... Signed-off-by: Andrea Mayer andrea.mayer@uniroma2.it Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 26882fd9323a..2e90672852c8 100644 --- a/net/ipv6/seg6_iptunnel.c +++ b/net/ipv6/seg6_iptunnel.c @@ -176,6 +176,8 @@ 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; @@ -228,6 +230,8 @@ 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; @@ -289,7 +293,6 @@ 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));
return 0;