From 271c3b9b7bdae09c7da467ac1ae96e3298754977 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Mon, 21 Dec 2015 21:29:26 +0100 Subject: [PATCH] tcp: honour SO_BINDTODEVICE for TW_RST case too Hannes points out that when we generate tcp reset for timewait sockets we pretend we found no socket and pass NULL sk to tcp_vX_send_reset(). Make it cope with inet tw sockets and then provide tw sk. This makes RSTs appear on correct interface when SO_BINDTODEVICE is used. Packetdrill test case: // want default route to be used, we rely on BINDTODEVICE `ip route del 192.0.2.0/24 via 192.168.0.2 dev tun0` 0.000 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 // test case still works due to BINDTODEVICE 0.001 setsockopt(3, SOL_SOCKET, SO_BINDTODEVICE, "tun0", 4) = 0 0.100...0.200 connect(3, ..., ...) = 0 0.100 > S 0:0(0) 0.200 < S. 0:0(0) ack 1 win 32792 0.200 > . 1:1(0) ack 1 0.210 close(3) = 0 0.210 > F. 1:1(0) ack 1 win 29200 0.300 < . 1:1(0) ack 2 win 46 // more data while in FIN_WAIT2, expect RST 1.300 < P. 1:1001(1000) ack 1 win 46 // fails without this change -- default route is used 1.301 > R 1:1(0) win 0 Reported-by: Hannes Frederic Sowa Signed-off-by: Florian Westphal Acked-by: Eric Dumazet Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- net/ipv4/tcp_ipv4.c | 12 +++++++++--- net/ipv4/tcp_minisocks.c | 7 ++----- net/ipv6/tcp_ipv6.c | 6 ++++-- 3 files changed, 15 insertions(+), 10 deletions(-) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index eb29c2f5bcea..fc4f72686705 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -627,7 +627,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); #ifdef CONFIG_TCP_MD5SIG hash_location = tcp_parse_md5sig_option(th); - if (sk) { + if (sk && sk_fullsock(sk)) { key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *) &ip_hdr(skb)->saddr, AF_INET); } else if (hash_location) { @@ -674,7 +674,8 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) ip_hdr(skb)->saddr, /* XXX */ arg.iov[0].iov_len, IPPROTO_TCP, 0); arg.csumoffset = offsetof(struct tcphdr, check) / 2; - arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0; + arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0; + /* When socket is gone, all binding information is lost. * routing might fail in this case. No choice here, if we choose to force * input interface, we will misroute in case of asymmetric route. @@ -682,6 +683,9 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) if (sk) arg.bound_dev_if = sk->sk_bound_dev_if; + BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) != + offsetof(struct inet_timewait_sock, tw_bound_dev_if)); + arg.tos = ip_hdr(skb)->tos; ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk), skb, &TCP_SKB_CB(skb)->header.h4.opt, @@ -1705,7 +1709,9 @@ do_time_wait: tcp_v4_timewait_ack(sk, skb); break; case TCP_TW_RST: - goto no_tcp_socket; + tcp_v4_send_reset(sk, skb); + inet_twsk_deschedule_put(inet_twsk(sk)); + goto discard_it; case TCP_TW_SUCCESS:; } goto discard_it; diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index ac6b1961ffeb..75632a925824 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -131,7 +131,7 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, goto kill; if (th->syn && !before(TCP_SKB_CB(skb)->seq, tcptw->tw_rcv_nxt)) - goto kill_with_rst; + return TCP_TW_RST; /* Dup ACK? */ if (!th->ack || @@ -145,11 +145,8 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, * reset. */ if (!th->fin || - TCP_SKB_CB(skb)->end_seq != tcptw->tw_rcv_nxt + 1) { -kill_with_rst: - inet_twsk_deschedule_put(tw); + TCP_SKB_CB(skb)->end_seq != tcptw->tw_rcv_nxt + 1) return TCP_TW_RST; - } /* FIN arrived, enter true time-wait state. */ tw->tw_substate = TCP_TIME_WAIT; diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 32fa0de9982a..9ecb012291cf 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -854,7 +854,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) #ifdef CONFIG_TCP_MD5SIG hash_location = tcp_parse_md5sig_option(th); - if (sk) { + if (sk && sk_fullsock(sk)) { key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr); } else if (hash_location) { /* @@ -1516,7 +1516,9 @@ do_time_wait: break; case TCP_TW_RST: tcp_v6_restore_cb(skb); - goto no_tcp_socket; + tcp_v6_send_reset(sk, skb); + inet_twsk_deschedule_put(inet_twsk(sk)); + goto discard_it; case TCP_TW_SUCCESS: ; } -- 2.20.1