6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
[ Upstream commit 4530e5b8e2dad63dcad2206232dd86e4b1489b6c ]
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@xxxxxxxxxxxxx>
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/gtp.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c
index acb20ad4e37eb..477b4d4f860bd 100644
--- a/drivers/net/gtp.c
+++ b/drivers/net/gtp.c
@@ -871,8 +871,9 @@ 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));
--
2.42.0
