From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Sun, 22 Oct 2023 20:25:18 +0000 (+0200)
Subject: gtp: fix fragmentation needed check with gso
X-Git-Tag: v6.6.7~1673^2~7^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=4530e5b8e2dad63dcad2206232dd86e4b1489b6c;p=platform%2Fkernel%2Flinux-starfive.git

gtp: fix fragmentation needed check with gso

Call skb_gso_validate_network_len() to check if packet is over PMTU.

Fixes: 459aa660eb1d ("gtp: add initial driver for datapath of GPRS Tunneling Protocol (GTP-U)")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---

diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c
index 144ec62..b22596b 100644
--- a/drivers/net/gtp.c
+++ b/drivers/net/gtp.c
@@ -872,8 +872,9 @@ static int gtp_build_skb_ip4(struct sk_buff *skb, struct net_device *dev,
 
 	skb_dst_update_pmtu_no_confirm(skb, mtu);
 
-	if (!skb_is_gso(skb) && (iph->frag_off & htons(IP_DF)) &&
-	    mtu < ntohs(iph->tot_len)) {
+	if (iph->frag_off & htons(IP_DF) &&
+	    ((!skb_is_gso(skb) && skb->len > mtu) ||
+	     (skb_is_gso(skb) && !skb_gso_validate_network_len(skb, mtu)))) {
 		netdev_dbg(dev, "packet too big, fragmentation needed\n");
 		icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
 			      htonl(mtu));