From f8a554b4aa9686bb2c12f6bae516e58783289a03 Mon Sep 17 00:00:00 2001 From: Stefano Brivio Date: Thu, 15 Mar 2018 17:17:13 +0100 Subject: [PATCH] vti6: Fix dev->max_mtu setting We shouldn't allow a tunnel to have IP_MAX_MTU as MTU, because another IPv6 header is going on top of our packets. Without this patch, we might end up building packets bigger than IP_MAX_MTU. Fixes: b96f9afee4eb ("ipv4/6: use core net MTU range checking") Signed-off-by: Stefano Brivio Acked-by: Sabrina Dubroca Signed-off-by: Steffen Klassert --- net/ipv6/ip6_vti.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c index 971175142e14..ce18cd20389d 100644 --- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -879,7 +879,7 @@ static void vti6_dev_setup(struct net_device *dev) dev->type = ARPHRD_TUNNEL6; dev->min_mtu = IPV6_MIN_MTU; - dev->max_mtu = IP_MAX_MTU; + dev->max_mtu = IP_MAX_MTU - sizeof(struct ipv6hdr); dev->flags |= IFF_NOARP; dev->addr_len = sizeof(struct in6_addr); netif_keep_dst(dev); -- 2.30.2