4.20-stable review patch. If anyone has any objections, please let me know.
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From: Yohei Kanemaru yohei.kanemaru@gmail.com
[ Upstream commit ef489749aae508e6f17886775c075f12ff919fb1 ]
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 yohei.kanemaru@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/seg6_iptunnel.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/net/ipv6/seg6_iptunnel.c +++ b/net/ipv6/seg6_iptunnel.c @@ -146,6 +146,8 @@ int seg6_do_srh_encap(struct sk_buff *sk } 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;