From 96fffb4f23f124f297d51dedc9cf51d19eb88ee1 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Sun, 9 Aug 2015 13:14:15 +0200 Subject: netfilter: ip6t_SYNPROXY: fix NULL pointer dereference This happens when networking namespaces are enabled. Suggested-by: Patrick McHardy Signed-off-by: Phil Sutter Acked-by: Patrick McHardy Signed-off-by: Pablo Neira Ayuso --- net/ipv6/netfilter/ip6t_SYNPROXY.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) (limited to 'net/ipv6') diff --git a/net/ipv6/netfilter/ip6t_SYNPROXY.c b/net/ipv6/netfilter/ip6t_SYNPROXY.c index 6edb7b106de7..bcebc24c6f0b 100644 --- a/net/ipv6/netfilter/ip6t_SYNPROXY.c +++ b/net/ipv6/netfilter/ip6t_SYNPROXY.c @@ -37,12 +37,13 @@ synproxy_build_ip(struct sk_buff *skb, const struct in6_addr *saddr, } static void -synproxy_send_tcp(const struct sk_buff *skb, struct sk_buff *nskb, +synproxy_send_tcp(const struct synproxy_net *snet, + const struct sk_buff *skb, struct sk_buff *nskb, struct nf_conntrack *nfct, enum ip_conntrack_info ctinfo, struct ipv6hdr *niph, struct tcphdr *nth, unsigned int tcp_hdr_size) { - struct net *net = nf_ct_net((struct nf_conn *)nfct); + struct net *net = nf_ct_net(snet->tmpl); struct dst_entry *dst; struct flowi6 fl6; @@ -83,7 +84,8 @@ free_nskb: } static void -synproxy_send_client_synack(const struct sk_buff *skb, const struct tcphdr *th, +synproxy_send_client_synack(const struct synproxy_net *snet, + const struct sk_buff *skb, const struct tcphdr *th, const struct synproxy_options *opts) { struct sk_buff *nskb; @@ -119,7 +121,7 @@ synproxy_send_client_synack(const struct sk_buff *skb, const struct tcphdr *th, synproxy_build_options(nth, opts); - synproxy_send_tcp(skb, nskb, skb->nfct, IP_CT_ESTABLISHED_REPLY, + synproxy_send_tcp(snet, skb, nskb, skb->nfct, IP_CT_ESTABLISHED_REPLY, niph, nth, tcp_hdr_size); } @@ -163,7 +165,7 @@ synproxy_send_server_syn(const struct synproxy_net *snet, synproxy_build_options(nth, opts); - synproxy_send_tcp(skb, nskb, &snet->tmpl->ct_general, IP_CT_NEW, + synproxy_send_tcp(snet, skb, nskb, &snet->tmpl->ct_general, IP_CT_NEW, niph, nth, tcp_hdr_size); } @@ -203,7 +205,7 @@ synproxy_send_server_ack(const struct synproxy_net *snet, synproxy_build_options(nth, opts); - synproxy_send_tcp(skb, nskb, NULL, 0, niph, nth, tcp_hdr_size); + synproxy_send_tcp(snet, skb, nskb, NULL, 0, niph, nth, tcp_hdr_size); } static void @@ -241,7 +243,7 @@ synproxy_send_client_ack(const struct synproxy_net *snet, synproxy_build_options(nth, opts); - synproxy_send_tcp(skb, nskb, NULL, 0, niph, nth, tcp_hdr_size); + synproxy_send_tcp(snet, skb, nskb, NULL, 0, niph, nth, tcp_hdr_size); } static bool @@ -301,7 +303,7 @@ synproxy_tg6(struct sk_buff *skb, const struct xt_action_param *par) XT_SYNPROXY_OPT_SACK_PERM | XT_SYNPROXY_OPT_ECN); - synproxy_send_client_synack(skb, th, &opts); + synproxy_send_client_synack(snet, skb, th, &opts); return NF_DROP; } else if (th->ack && !(th->fin || th->rst || th->syn)) { -- cgit v1.2.3 From 3c16241c445303a90529565e7437e1f240acfef2 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Tue, 28 Jul 2015 00:53:26 +0200 Subject: netfilter: SYNPROXY: fix sending window update to client Upon receipt of SYNACK from the server, ipt_SYNPROXY first sends back an ACK to finish the server handshake, then calls nf_ct_seqadj_init() to initiate sequence number adjustment of forwarded packets to the client and finally sends a window update to the client to unblock it's TX queue. Since synproxy_send_client_ack() does not set synproxy_send_tcp()'s nfct parameter, no sequence number adjustment happens and the client receives the window update with incorrect sequence number. Depending on client TCP implementation, this leads to a significant delay (until a window probe is being sent). Signed-off-by: Phil Sutter Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/ipt_SYNPROXY.c | 3 ++- net/ipv6/netfilter/ip6t_SYNPROXY.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) (limited to 'net/ipv6') diff --git a/net/ipv4/netfilter/ipt_SYNPROXY.c b/net/ipv4/netfilter/ipt_SYNPROXY.c index fe8cc183411e..95ea633e8356 100644 --- a/net/ipv4/netfilter/ipt_SYNPROXY.c +++ b/net/ipv4/netfilter/ipt_SYNPROXY.c @@ -226,7 +226,8 @@ synproxy_send_client_ack(const struct synproxy_net *snet, synproxy_build_options(nth, opts); - synproxy_send_tcp(skb, nskb, NULL, 0, niph, nth, tcp_hdr_size); + synproxy_send_tcp(skb, nskb, skb->nfct, IP_CT_ESTABLISHED_REPLY, + niph, nth, tcp_hdr_size); } static bool diff --git a/net/ipv6/netfilter/ip6t_SYNPROXY.c b/net/ipv6/netfilter/ip6t_SYNPROXY.c index bcebc24c6f0b..ebbb754c2111 100644 --- a/net/ipv6/netfilter/ip6t_SYNPROXY.c +++ b/net/ipv6/netfilter/ip6t_SYNPROXY.c @@ -243,7 +243,8 @@ synproxy_send_client_ack(const struct synproxy_net *snet, synproxy_build_options(nth, opts); - synproxy_send_tcp(snet, skb, nskb, NULL, 0, niph, nth, tcp_hdr_size); + synproxy_send_tcp(snet, skb, nskb, skb->nfct, IP_CT_ESTABLISHED_REPLY, + niph, nth, tcp_hdr_size); } static bool -- cgit v1.2.3