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Commit 5b010147 authored by Sabrina Dubroca's avatar Sabrina Dubroca Committed by David S. Miller
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geneve: avoid use-after-free of skb->data 



geneve{,6}_build_skb can end up doing a pskb_expand_head(), which
makes the ip_hdr(skb) reference we stashed earlier stale. Since it's
only needed as an argument to ip_tunnel_ecn_encap(), move this
directly in the function call.

Fixes: 08399efc ("geneve: ensure ECN info is handled properly in all tx/rx paths")
Signed-off-by: default avatarSabrina Dubroca <sd@queasysnail.net>
Reviewed-by: default avatarJohn W. Linville <linville@tuxdriver.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3de81b75

drivers/net/geneve.c

+4 −10
Original line number Diff line number Diff line
@@ -859,7 +859,6 @@ static netdev_tx_t geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev, 
	struct geneve_dev *geneve = netdev_priv(dev);

	struct geneve_sock *gs4;

	struct rtable *rt = NULL;

	const struct iphdr *iip; /* interior IP header */

	int err = -EINVAL;

	struct flowi4 fl4;

	__u8 tos, ttl;
@@ -890,8 +889,6 @@ static netdev_tx_t geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev, 
	sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true);

	skb_reset_mac_header(skb);



	iip = ip_hdr(skb);



	if (info) {

		const struct ip_tunnel_key *key = &info->key;

		u8 *opts = NULL;
@@ -911,7 +908,7 @@ static netdev_tx_t geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev, 
		if (unlikely(err))

			goto tx_error;



		tos = ip_tunnel_ecn_encap(key->tos, iip, skb);

		tos = ip_tunnel_ecn_encap(key->tos, ip_hdr(skb), skb);

		ttl = key->ttl;

		df = key->tun_flags & TUNNEL_DONT_FRAGMENT ? htons(IP_DF) : 0;

	} else {
@@ -920,7 +917,7 @@ static netdev_tx_t geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev, 
		if (unlikely(err))

			goto tx_error;



		tos = ip_tunnel_ecn_encap(fl4.flowi4_tos, iip, skb);

		tos = ip_tunnel_ecn_encap(fl4.flowi4_tos, ip_hdr(skb), skb);

		ttl = geneve->ttl;

		if (!ttl && IN_MULTICAST(ntohl(fl4.daddr)))

			ttl = 1;
@@ -952,7 +949,6 @@ static netdev_tx_t geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev, 
{

	struct geneve_dev *geneve = netdev_priv(dev);

	struct dst_entry *dst = NULL;

	const struct iphdr *iip; /* interior IP header */

	struct geneve_sock *gs6;

	int err = -EINVAL;

	struct flowi6 fl6;
@@ -982,8 +978,6 @@ static netdev_tx_t geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev, 
	sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true);

	skb_reset_mac_header(skb);



	iip = ip_hdr(skb);



	if (info) {

		const struct ip_tunnel_key *key = &info->key;

		u8 *opts = NULL;
@@ -1004,7 +998,7 @@ static netdev_tx_t geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev, 
		if (unlikely(err))

			goto tx_error;



		prio = ip_tunnel_ecn_encap(key->tos, iip, skb);

		prio = ip_tunnel_ecn_encap(key->tos, ip_hdr(skb), skb);

		ttl = key->ttl;

		label = info->key.label;

	} else {
@@ -1014,7 +1008,7 @@ static netdev_tx_t geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev, 
			goto tx_error;



		prio = ip_tunnel_ecn_encap(ip6_tclass(fl6.flowlabel),

					   iip, skb);

					   ip_hdr(skb), skb);

		ttl = geneve->ttl;

		if (!ttl && ipv6_addr_is_multicast(&fl6.daddr))

			ttl = 1;