From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Stefano Brivio , Sabrina Dubroca , Steffen Klassert , Sasha Levin Subject: [PATCH 4.14 266/496] vti6: Fix dev->max_mtu setting Date: Mon, 28 May 2018 12:00:51 +0200 Message-Id: <20180528100331.071260733@linuxfoundation.org> In-Reply-To: <20180528100319.498712256@linuxfoundation.org> References: <20180528100319.498712256@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stefano Brivio [ Upstream commit f8a554b4aa9686bb2c12f6bae516e58783289a03 ] 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 Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/ipv6/ip6_vti.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -852,7 +852,7 @@ static void vti6_dev_setup(struct net_de dev->hard_header_len = LL_MAX_HEADER + sizeof(struct ipv6hdr); dev->mtu = ETH_DATA_LEN; 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);