From: Eric Dumazet Date: Thu, 23 Jul 2026 14:42:48 +0000 (+0000) Subject: vxlan: use pskb_network_may_pull() in route_shortcircuit() X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=26bb2dd0a8839617e2c79ffbbe1923f8e4bab9fb;p=thirdparty%2Flinux.git vxlan: use pskb_network_may_pull() in route_shortcircuit() route_shortcircuit() currently calls pskb_may_pull(skb, sizeof(struct iphdr)) (or ipv6hdr), which checks if bytes are available starting from skb->data. However, in vxlan_xmit(), skb->data points to the MAC header, so skb_network_offset(skb) is ETH_HLEN (14 bytes). Using pskb_may_pull(skb, 20) only checks 20 bytes from skb->data (which is 14 bytes MAC header + 6 bytes of IP header), leaving the rest of the IP header potentially un-pulled in non-linear frags. Subsequent dereferences of ip_hdr(skb)->daddr can read beyond the pulled linear buffer length. Fix this by using pskb_network_may_pull(), which adds skb_network_offset(skb) to the length check to ensure the full network header is present in the linear buffer. Fixes: e4f67addf158 ("add DOVE extensions for VXLAN") Cc: stable@vger.kernel.org Signed-off-by: Eric Dumazet Reviewed-by: Vadim Fedorenko Link: https://patch.msgid.link/20260723144249.759100-5-edumazet@google.com Signed-off-by: Jakub Kicinski --- diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c index be3c2bc2cd9a..2163e2687db0 100644 --- a/drivers/net/vxlan/vxlan_core.c +++ b/drivers/net/vxlan/vxlan_core.c @@ -2111,7 +2111,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb) { struct iphdr *pip; - if (!pskb_may_pull(skb, sizeof(struct iphdr))) + if (!pskb_network_may_pull(skb, sizeof(struct iphdr))) return false; pip = ip_hdr(skb); n = neigh_lookup(&arp_tbl, &pip->daddr, dev); @@ -2137,7 +2137,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb) */ if (!ipv6_mod_enabled()) return false; - if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) + if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr))) return false; pip6 = ipv6_hdr(skb); n = neigh_lookup(&nd_tbl, &pip6->daddr, dev);