From 9f10d3f6f966ef6f6a8d025a4b1d341923d04607 Mon Sep 17 00:00:00 2001 From: Neal Cardwell Date: Thu, 28 Jun 2012 12:34:21 +0000 Subject: [PATCH] tcp: plug dst leak in tcp_v6_conn_request() The code in tcp_v6_conn_request() was implicitly assuming that tcp_v6_send_synack() would take care of dst_release(), much as tcp_v4_send_synack() already does. This resulted in tcp_v6_conn_request() leaking a dst if sysctl_tw_recycle is enabled. This commit restructures tcp_v6_send_synack() so that it accepts a dst pointer and takes care of releasing the dst that is passed in, to plug the leak and avoid future surprises by bringing the IPv6 behavior in line with the IPv4 side. Signed-off-by: Neal Cardwell Signed-off-by: David S. Miller --- net/ipv6/tcp_ipv6.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index d1db0caefdcd..9c06eafaf695 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -477,7 +477,8 @@ out: } -static int tcp_v6_send_synack(struct sock *sk, +static int tcp_v6_send_synack(struct sock *sk, struct dst_entry *dst, + struct flowi6 *fl6, struct request_sock *req, struct request_values *rvp, u16 queue_mapping) @@ -486,12 +487,10 @@ static int tcp_v6_send_synack(struct sock *sk, struct ipv6_pinfo *np = inet6_sk(sk); struct sk_buff * skb; struct ipv6_txoptions *opt = np->opt; - struct flowi6 fl6; - struct dst_entry *dst; int err = -ENOMEM; - dst = inet6_csk_route_req(sk, &fl6, req); - if (!dst) + /* First, grab a route. */ + if (!dst && (dst = inet6_csk_route_req(sk, fl6, req)) == NULL) goto done; skb = tcp_make_synack(sk, dst, req, rvp); @@ -499,9 +498,9 @@ static int tcp_v6_send_synack(struct sock *sk, if (skb) { __tcp_v6_send_check(skb, &treq->loc_addr, &treq->rmt_addr); - fl6.daddr = treq->rmt_addr; + fl6->daddr = treq->rmt_addr; skb_set_queue_mapping(skb, queue_mapping); - err = ip6_xmit(sk, skb, &fl6, opt, np->tclass); + err = ip6_xmit(sk, skb, fl6, opt, np->tclass); err = net_xmit_eval(err); } @@ -514,8 +513,10 @@ done: static int tcp_v6_rtx_synack(struct sock *sk, struct request_sock *req, struct request_values *rvp) { + struct flowi6 fl6; + TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS); - return tcp_v6_send_synack(sk, req, rvp, 0); + return tcp_v6_send_synack(sk, NULL, &fl6, req, rvp, 0); } static void tcp_v6_reqsk_destructor(struct request_sock *req) @@ -1201,7 +1202,7 @@ have_isn: if (security_inet_conn_request(sk, skb, req)) goto drop_and_release; - if (tcp_v6_send_synack(sk, req, + if (tcp_v6_send_synack(sk, dst, &fl6, req, (struct request_values *)&tmp_ext, skb_get_queue_mapping(skb)) || want_cookie)