In vti6_xmit(), the check for IPV6_MIN_MTU before we send a ICMPV6_PKT_TOOBIG message is missing. So we might report a PMTU below 1280. Fix this by adding the required check.
Fixes: ccd740cbc6e ("vti6: Add pmtu handling to vti6_xmit.") Signed-off-by: Steffen Klassert <steffen.klass...@secunet.com> --- net/ipv6/ip6_vti.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c index d82042c..9156d6b 100644 --- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -484,11 +484,15 @@ static bool vti6_state_check(const struct xfrm_state *x, if (!skb->ignore_df && skb->len > mtu) { skb_dst(skb)->ops->update_pmtu(dst, NULL, skb, mtu); - if (skb->protocol == htons(ETH_P_IPV6)) + if (skb->protocol == htons(ETH_P_IPV6)) { + if (mtu < IPV6_MIN_MTU) + mtu = IPV6_MIN_MTU; + icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); - else + } else { icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu)); + } return -EMSGSIZE; } -- 1.9.1