From 5b01014759991887b1e450c9def01e58c02ab81b Mon Sep 17 00:00:00 2001 From: Sabrina Dubroca Date: Fri, 2 Dec 2016 16:49:29 +0100 Subject: [PATCH] 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: 08399efc6319 ("geneve: ensure ECN info is handled properly in all tx/rx paths") Signed-off-by: Sabrina Dubroca Reviewed-by: John W. Linville Signed-off-by: David S. Miller --- drivers/net/geneve.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c index 42edd7b7902f..8b4822ad27cb 100644 --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -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; -- 2.20.1