4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Florian Westphal fw@strlen.de
commit 29e09229d9f26129a39462fae0ddabc4d9533989 upstream.
inet_sk(skb->sk) is illegal in case skb is attached to request socket.
Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener") Reported by: Daniel J Blueman daniel@quora.org Signed-off-by: Florian Westphal fw@strlen.de Tested-by: Daniel J Blueman daniel@quora.org Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/ipv4/netfilter.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
--- a/net/ipv4/netfilter.c +++ b/net/ipv4/netfilter.c @@ -23,7 +23,8 @@ int ip_route_me_harder(struct net *net, struct rtable *rt; struct flowi4 fl4 = {}; __be32 saddr = iph->saddr; - __u8 flags = skb->sk ? inet_sk_flowi_flags(skb->sk) : 0; + const struct sock *sk = skb_to_full_sk(skb); + __u8 flags = sk ? inet_sk_flowi_flags(sk) : 0; unsigned int hh_len;
if (addr_type == RTN_UNSPEC) @@ -39,7 +40,7 @@ int ip_route_me_harder(struct net *net, fl4.daddr = iph->daddr; fl4.saddr = saddr; fl4.flowi4_tos = RT_TOS(iph->tos); - fl4.flowi4_oif = skb->sk ? skb->sk->sk_bound_dev_if : 0; + fl4.flowi4_oif = sk ? sk->sk_bound_dev_if : 0; fl4.flowi4_mark = skb->mark; fl4.flowi4_flags = flags; rt = ip_route_output_key(net, &fl4); @@ -58,7 +59,7 @@ int ip_route_me_harder(struct net *net, xfrm_decode_session(skb, flowi4_to_flowi(&fl4), AF_INET) == 0) { struct dst_entry *dst = skb_dst(skb); skb_dst_set(skb, NULL); - dst = xfrm_lookup(net, dst, flowi4_to_flowi(&fl4), skb->sk, 0); + dst = xfrm_lookup(net, dst, flowi4_to_flowi(&fl4), sk, 0); if (IS_ERR(dst)) return PTR_ERR(dst); skb_dst_set(skb, dst);