From: Yohei Kanemaru Date: Tue, 29 Jan 2019 06:52:34 +0000 (+0900) Subject: ipv6: sr: clear IP6CB(skb) on SRH ip4ip6 encapsulation X-Git-Url: http://git.rot13.org/?a=commitdiff_plain;h=ef489749aae508e6f17886775c075f12ff919fb1;p=linux ipv6: sr: clear IP6CB(skb) on SRH ip4ip6 encapsulation skb->cb may contain data from previous layers (in an observed case IPv4 with L3 Master Device). In the observed scenario, the data in IPCB(skb)->frags was misinterpreted as IP6CB(skb)->frag_max_size, eventually caused an unexpected IPv6 fragmentation in ip6_fragment() through ip6_finish_output(). This patch clears IP6CB(skb), which potentially contains garbage data, on the SRH ip4ip6 encapsulation. Fixes: 32d99d0b6702 ("ipv6: sr: add support for ip4ip6 encapsulation") Signed-off-by: Yohei Kanemaru Signed-off-by: David S. Miller --- diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c index 8181ee7e1e27..ee5403cbe655 100644 --- a/net/ipv6/seg6_iptunnel.c +++ b/net/ipv6/seg6_iptunnel.c @@ -146,6 +146,8 @@ int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto) } else { ip6_flow_hdr(hdr, 0, flowlabel); hdr->hop_limit = ip6_dst_hoplimit(skb_dst(skb)); + + memset(IP6CB(skb), 0, sizeof(*IP6CB(skb))); } hdr->nexthdr = NEXTHDR_ROUTING;