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Date: Mon, 21 Dec 2015 17:20:09 +0100
From: Florian Westphal <fw@...len.de>
To: <netdev@...r.kernel.org>
Cc: eric.dumazet@...il.com, Florian Westphal <fw@...len.de>
Subject: [PATCH -next] 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 so RST appears on
correct interface.
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
0.001 setsockopt(3, SOL_SOCKET, SO_BINDTODEVICE, "tun0", 4) = 0
0.100...0.200 connect(3, ..., ...) = 0
0.100 > S 0:0(0) <mss 1460,sackOK,nop,nop>
0.200 < S. 0:0(0) ack 1 win 32792 <mss 1460,sackOK,nop,nop>
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 <hannes@...essinduktion.org>
Signed-off-by: Florian Westphal <fw@...len.de>
---
net/ipv4/tcp_ipv4.c | 31 ++++++++++++++++++++++---------
net/ipv4/tcp_minisocks.c | 7 ++-----
net/ipv6/tcp_ipv6.c | 15 +++++++++++----
3 files changed, 35 insertions(+), 18 deletions(-)
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 46e92fb..24ba2e1 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -587,13 +587,14 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
} rep;
struct ip_reply_arg arg;
#ifdef CONFIG_TCP_MD5SIG
- struct tcp_md5sig_key *key;
+ struct tcp_md5sig_key *key = NULL;
const __u8 *hash_location = NULL;
unsigned char newhash[16];
int genhash;
struct sock *sk1 = NULL;
#endif
struct net *net;
+ bool have_full_sk;
/* Never send a reset in response to a reset. */
if (th->rst)
@@ -624,10 +625,14 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
arg.iov[0].iov_base = (unsigned char *)&rep;
arg.iov[0].iov_len = sizeof(rep.th);
- net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
+ have_full_sk = sk && sk_fullsock(sk);
+ net = have_full_sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
#ifdef CONFIG_TCP_MD5SIG
hash_location = tcp_parse_md5sig_option(th);
- if (!sk && hash_location) {
+ if (have_full_sk) {
+ key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
+ &ip_hdr(skb)->saddr, AF_INET);
+ } else if (hash_location) {
/*
* active side is lost. Try to find listening socket through
* source port, and then find md5 key through listening socket.
@@ -651,10 +656,6 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
if (genhash || memcmp(hash_location, newhash, 16) != 0)
goto release_sk1;
- } else {
- key = sk ? tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
- &ip_hdr(skb)->saddr,
- AF_INET) : NULL;
}
if (key) {
@@ -675,7 +676,14 @@ 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 = 0;
+ if (have_full_sk) {
+ if (inet_sk(sk)->transparent)
+ arg.flags = IP_REPLY_ARG_NOSRCCHECK;
+ } else if (sk && inet_twsk(sk)->tw_transparent) {
+ arg.flags = IP_REPLY_ARG_NOSRCCHECK;
+ }
+
/* 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.
@@ -683,6 +691,9 @@ 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,
@@ -1706,7 +1717,9 @@ 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 ac6b196..75632a9 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 f03d2b0..2637b61 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -841,6 +841,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
int genhash;
struct sock *sk1 = NULL;
#endif
+ bool have_full_sk;
int oif;
if (th->rst)
@@ -852,9 +853,12 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
if (!sk && !ipv6_unicast_destination(skb))
return;
+ have_full_sk = sk && sk_fullsock(sk);
#ifdef CONFIG_TCP_MD5SIG
hash_location = tcp_parse_md5sig_option(th);
- if (!sk && hash_location) {
+ if (have_full_sk) {
+ key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr);
+ } else if (hash_location) {
/*
* active side is lost. Try to find listening socket through
* source port, and then find md5 key through listening socket.
@@ -877,8 +881,6 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
if (genhash || memcmp(hash_location, newhash, 16) != 0)
goto release_sk1;
- } else {
- key = sk ? tcp_v6_md5_do_lookup(sk, &ipv6h->saddr) : NULL;
}
#endif
@@ -889,6 +891,9 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
(th->doff << 2);
oif = sk ? sk->sk_bound_dev_if : 0;
+ if (!have_full_sk)
+ sk = NULL;
+
tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0);
#ifdef CONFIG_TCP_MD5SIG
@@ -1516,7 +1521,9 @@ 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:
;
}
--
2.4.10
--
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