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: 08399efc63 ("geneve: ensure ECN info is handled properly in all tx/rx paths")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Sabrina Dubroca 2016-12-02 16:49:29 +01:00 committed by David S. Miller
parent 3de81b7588
commit 5b01014759

View File

@ -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;