diff options
| author | Eric Dumazet <edumazet@google.com> | 2026-05-25 20:36:42 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-05-26 18:10:55 -0700 |
| commit | 7d9ef0cb271555d8cf39fefe6c981e1493b25ecf (patch) | |
| tree | 8eb447e2c4b9aa1abf729a7a39fa12b62637c37a /drivers/net | |
| parent | b4bc94353050b1fa7b702bd4c6600710dd926cff (diff) | |
| download | lwn-7d9ef0cb271555d8cf39fefe6c981e1493b25ecf.tar.gz lwn-7d9ef0cb271555d8cf39fefe6c981e1493b25ecf.zip | |
vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu()
skb_tunnel_check_pmtu() can change skb->head.
Reusing old_iph afer skb_tunnel_check_pmtu() can cause an UAF.
Use instead ip_hdr(skb) as done in drivers/net/bareudp.c
and drivers/net/geneve.c.
Found by Sashiko.
Fixes: 4cb47a8644cc ("tunnels: PMTU discovery support for directly bridged IP packets")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Link: https://patch.msgid.link/20260525203642.2389723-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/net')
| -rw-r--r-- | drivers/net/vxlan/vxlan_core.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c index e88798497503..b5b1253ac08b 100644 --- a/drivers/net/vxlan/vxlan_core.c +++ b/drivers/net/vxlan/vxlan_core.c @@ -2531,7 +2531,7 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, goto out_unlock; } - tos = ip_tunnel_ecn_encap(tos, old_iph, skb); + tos = ip_tunnel_ecn_encap(tos, ip_hdr(skb), skb); ttl = ttl ? : ip4_dst_hoplimit(&rt->dst); err = vxlan_build_skb(skb, ndst, sizeof(struct iphdr), vni, md, flags, udp_sum); @@ -2605,7 +2605,7 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, goto out_unlock; } - tos = ip_tunnel_ecn_encap(tos, old_iph, skb); + tos = ip_tunnel_ecn_encap(tos, ip_hdr(skb), skb); ttl = ttl ? : ip6_dst_hoplimit(ndst); skb_scrub_packet(skb, xnet); err = vxlan_build_skb(skb, ndst, sizeof(struct ipv6hdr), |