1 files changed, 48 insertions, 60 deletions

diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index 12eedc6ca2..c8d2ca2722 100644
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -114,76 +114,82 @@ __u32 cookie_v6_init_sequence(const struct sk_buff *skb, __u16 *mssp)
 	return __cookie_v6_init_sequence(iph, th, mssp);
 }
 
-int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th,
-		      __u32 cookie)
+int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th)
 {
+	__u32 cookie = ntohl(th->ack_seq) - 1;
 	__u32 seq = ntohl(th->seq) - 1;
-	__u32 mssind = check_tcp_syn_cookie(cookie, &iph->saddr, &iph->daddr,
-					    th->source, th->dest, seq);
+	__u32 mssind;
+
+	mssind = check_tcp_syn_cookie(cookie, &iph->saddr, &iph->daddr,
+				      th->source, th->dest, seq);
 
 	return mssind < ARRAY_SIZE(msstab) ? msstab[mssind] : 0;
 }
 EXPORT_SYMBOL_GPL(__cookie_v6_check);
 
-struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
+static struct request_sock *cookie_tcp_check(struct net *net, struct sock *sk,
+					     struct sk_buff *skb)
 {
 	struct tcp_options_received tcp_opt;
-	struct inet_request_sock *ireq;
-	struct tcp_request_sock *treq;
-	struct ipv6_pinfo *np = inet6_sk(sk);
-	struct tcp_sock *tp = tcp_sk(sk);
-	const struct tcphdr *th = tcp_hdr(skb);
-	__u32 cookie = ntohl(th->ack_seq) - 1;
-	struct sock *ret = sk;
-	struct request_sock *req;
-	int full_space, mss;
-	struct dst_entry *dst;
-	__u8 rcv_wscale;
 	u32 tsoff = 0;
-	int l3index;
-
-	if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_syncookies) ||
-	    !th->ack || th->rst)
-		goto out;
+	int mss;
 
 	if (tcp_synq_no_recent_overflow(sk))
 		goto out;
 
-	mss = __cookie_v6_check(ipv6_hdr(skb), th, cookie);
-	if (mss == 0) {
-		__NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESFAILED);
+	mss = __cookie_v6_check(ipv6_hdr(skb), tcp_hdr(skb));
+	if (!mss) {
+		__NET_INC_STATS(net, LINUX_MIB_SYNCOOKIESFAILED);
 		goto out;
 	}
 
-	__NET_INC_STATS(sock_net(sk), LINUX_MIB_SYNCOOKIESRECV);
+	__NET_INC_STATS(net, LINUX_MIB_SYNCOOKIESRECV);
 
 	/* check for timestamp cookie support */
 	memset(&tcp_opt, 0, sizeof(tcp_opt));
-	tcp_parse_options(sock_net(sk), skb, &tcp_opt, 0, NULL);
+	tcp_parse_options(net, skb, &tcp_opt, 0, NULL);
 
 	if (tcp_opt.saw_tstamp && tcp_opt.rcv_tsecr) {
-		tsoff = secure_tcpv6_ts_off(sock_net(sk),
+		tsoff = secure_tcpv6_ts_off(net,
 					    ipv6_hdr(skb)->daddr.s6_addr32,
 					    ipv6_hdr(skb)->saddr.s6_addr32);
 		tcp_opt.rcv_tsecr -= tsoff;
 	}
 
-	if (!cookie_timestamp_decode(sock_net(sk), &tcp_opt))
+	if (!cookie_timestamp_decode(net, &tcp_opt))
 		goto out;
 
-	ret = NULL;
-	req = cookie_tcp_reqsk_alloc(&tcp6_request_sock_ops,
-				     &tcp_request_sock_ipv6_ops, sk, skb);
-	if (!req)
+	return cookie_tcp_reqsk_alloc(&tcp6_request_sock_ops, sk, skb,
+				      &tcp_opt, mss, tsoff);
+out:
+	return ERR_PTR(-EINVAL);
+}
+
+struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
+{
+	const struct tcphdr *th = tcp_hdr(skb);
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct tcp_sock *tp = tcp_sk(sk);
+	struct inet_request_sock *ireq;
+	struct net *net = sock_net(sk);
+	struct request_sock *req;
+	struct dst_entry *dst;
+	struct sock *ret = sk;
+	__u8 rcv_wscale;
+	int full_space;
+
+	if (!READ_ONCE(net->ipv4.sysctl_tcp_syncookies) ||
+	    !th->ack || th->rst)
 		goto out;
 
+	req = cookie_tcp_check(net, sk, skb);
+	if (IS_ERR(req))
+		goto out;
+	if (!req)
+		goto out_drop;
+
 	ireq = inet_rsk(req);
-	treq = tcp_rsk(req);
-	treq->tfo_listener = false;
 
-	req->mss = mss;
-	ireq->ir_rmt_port = th->source;
-	ireq->ir_num = ntohs(th->dest);
 	ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;
 	ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
 
@@ -197,31 +203,12 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
 		ireq->pktopts = skb;
 	}
 
-	ireq->ir_iif = inet_request_bound_dev_if(sk, skb);
 	/* So that link locals have meaning */
 	if (!sk->sk_bound_dev_if &&
 	    ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
 		ireq->ir_iif = tcp_v6_iif(skb);
 
-	ireq->ir_mark = inet_request_mark(sk, skb);
-
-	req->num_retrans = 0;
-	ireq->snd_wscale	= tcp_opt.snd_wscale;
-	ireq->sack_ok		= tcp_opt.sack_ok;
-	ireq->wscale_ok		= tcp_opt.wscale_ok;
-	ireq->tstamp_ok		= tcp_opt.saw_tstamp;
-	req->ts_recent		= tcp_opt.saw_tstamp ? tcp_opt.rcv_tsval : 0;
-	treq->snt_synack	= 0;
-	treq->rcv_isn = ntohl(th->seq) - 1;
-	treq->snt_isn = cookie;
-	treq->ts_off = 0;
-	treq->txhash = net_tx_rndhash();
-
-	l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
-	tcp_ao_syncookie(sk, skb, treq, AF_INET6, l3index);
-
-	if (IS_ENABLED(CONFIG_SMC))
-		ireq->smc_ok = 0;
+	tcp_ao_syncookie(sk, skb, req, AF_INET6);
 
 	/*
 	 * We need to lookup the dst_entry to get the correct window size.
@@ -243,7 +230,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
 		fl6.flowi6_uid = sk->sk_uid;
 		security_req_classify_flow(req, flowi6_to_flowi_common(&fl6));
 
-		dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
+		dst = ip6_dst_lookup_flow(net, sk, &fl6, final_p);
 		if (IS_ERR(dst))
 			goto out_free;
 	}
@@ -261,12 +248,13 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
 				  dst_metric(dst, RTAX_INITRWND));
 
 	ireq->rcv_wscale = rcv_wscale;
-	ireq->ecn_ok = cookie_ecn_ok(&tcp_opt, sock_net(sk), dst);
+	ireq->ecn_ok &= cookie_ecn_ok(net, dst);
 
-	ret = tcp_get_cookie_sock(sk, skb, req, dst, tsoff);
+	ret = tcp_get_cookie_sock(sk, skb, req, dst);
 out:
 	return ret;
 out_free:
 	reqsk_free(req);
+out_drop:
 	return NULL;
 }