[SRU][G][PATCH 1/1] net: geneve: modify IP header check in geneve6_xmit_skb and geneve_xmit_skb

[Kleber Sacilotto de Souza]

From: Phillip Potter <phil at philpotter.co.uk>

BugLink: https://bugs.launchpad.net/bugs/1931731

Modify the header size check in geneve6_xmit_skb and geneve_xmit_skb
to use pskb_inet_may_pull rather than pskb_network_may_pull. This fixes
two kernel selftest failures introduced by the commit introducing the
checks:
IPv4 over geneve6: PMTU exceptions
IPv4 over geneve6: PMTU exceptions - nexthop objects

It does this by correctly accounting for the fact that IPv4 packets may
transit over geneve IPv6 tunnels (and vice versa), and still fixes the
uninit-value bug fixed by the original commit.

Reported-by: kernel test robot <oliver.sang at intel.com>
Fixes: 6628ddfec758 ("net: geneve: check skb is large enough for IPv4/IPv6 header")
Suggested-by: Sabrina Dubroca <sd at queasysnail.net>
Signed-off-by: Phillip Potter <phil at philpotter.co.uk>
Acked-by: Sabrina Dubroca <sd at queasysnail.net>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit d13f048dd40e8577260cd43faea8ec9b77520197)
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza at canonical.com>
---
 drivers/net/geneve.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index c4beb7ce471a..40f30656a62a 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -891,7 +891,7 @@ static int geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	__be16 sport;
 	int err;
 
-	if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
+	if (!pskb_inet_may_pull(skb))
 		return -EINVAL;
 
 	sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true);
@@ -957,7 +957,7 @@ static int geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	__be16 sport;
 	int err;
 
-	if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
+	if (!pskb_inet_may_pull(skb))
 		return -EINVAL;
 
 	sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true);
-- 
2.27.0