Commit 5bc56388 authored by Geliang Tang's avatar Geliang Tang Committed by Jakub Kicinski
Browse files

mptcp: add port number check for MP_JOIN 



This patch adds two new helpers, subflow_use_different_sport and
subflow_use_different_dport, to check whether the subflow's source or
destination port number is different from the msk's port number. When
receiving the MP_JOIN's SYN/SYNACK/ACK, we do these port number checks
and print out the different port numbers.

And furthermore, when receiving the MP_JOIN's SYN/ACK, we also use a new
helper mptcp_pm_sport_in_anno_list to check whether this port number is
announced. If it isn't, we need to abort this connection.

This patch also populates the local address's port field in
local_address.

Signed-off-by: default avatarGeliang Tang <geliangtang@gmail.com>
Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent ec20e143

net/mptcp/pm_netlink.c

+22 −1
Original line number Diff line number Diff line
@@ -97,8 +97,8 @@ static bool address_zero(const struct mptcp_addr_info *addr) 
static void local_address(const struct sock_common *skc,

			  struct mptcp_addr_info *addr)

{

	addr->port = 0;

	addr->family = skc->skc_family;

	addr->port = htons(skc->skc_num);

	if (addr->family == AF_INET)

		addr->addr.s_addr = skc->skc_rcv_saddr;

#if IS_ENABLED(CONFIG_MPTCP_IPV6)
@@ -254,6 +254,27 @@ lookup_anno_list_by_saddr(struct mptcp_sock *msk, 
	return NULL;

}



bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk)

{

	struct mptcp_pm_add_entry *entry;

	struct mptcp_addr_info saddr;

	bool ret = false;



	local_address((struct sock_common *)sk, &saddr);



	spin_lock_bh(&msk->pm.lock);

	list_for_each_entry(entry, &msk->pm.anno_list, list) {

		if (addresses_equal(&entry->addr, &saddr, true)) {

			ret = true;

			goto out;

		}

	}



out:

	spin_unlock_bh(&msk->pm.lock);

	return ret;

}



static void mptcp_pm_add_timer(struct timer_list *timer)

{

	struct mptcp_pm_add_entry *entry = from_timer(entry, timer, add_timer);

net/mptcp/protocol.h

+1 −0
Original line number Diff line number Diff line
@@ -650,6 +650,7 @@ int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk, 
				 struct mptcp_addr_info *addr,

				 u8 bkup);

void mptcp_pm_free_anno_list(struct mptcp_sock *msk);

bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);

struct mptcp_pm_add_entry *

mptcp_pm_del_add_timer(struct mptcp_sock *msk,

		       struct mptcp_addr_info *addr);

net/mptcp/subflow.c

+38 −0
Original line number Diff line number Diff line
@@ -120,6 +120,11 @@ static int __subflow_init_req(struct request_sock *req, const struct sock *sk_li 
	return 0;

}



static bool subflow_use_different_sport(struct mptcp_sock *msk, const struct sock *sk)

{

	return inet_sk(sk)->inet_sport != inet_sk((struct sock *)msk)->inet_sport;

}



/* Init mptcp request socket.

 *

 * Returns an error code if a JOIN has failed and a TCP reset
@@ -192,6 +197,20 @@ static int subflow_init_req(struct request_sock *req, 
		if (!subflow_req->msk)

			return -EPERM;



		if (subflow_use_different_sport(subflow_req->msk, sk_listener)) {

			pr_debug("syn inet_sport=%d %d",

				 ntohs(inet_sk(sk_listener)->inet_sport),

				 ntohs(inet_sk((struct sock *)subflow_req->msk)->inet_sport));

			if (!mptcp_pm_sport_in_anno_list(subflow_req->msk, sk_listener)) {

				sock_put((struct sock *)subflow_req->msk);

				mptcp_token_destroy_request(req);

				tcp_request_sock_ops.destructor(req);

				subflow_req->msk = NULL;

				subflow_req->mp_join = 0;

				return -EPERM;

			}

		}



		subflow_req_create_thmac(subflow_req);



		if (unlikely(req->syncookie)) {
@@ -336,6 +355,11 @@ void mptcp_subflow_reset(struct sock *ssk) 
	sock_put(sk);

}



static bool subflow_use_different_dport(struct mptcp_sock *msk, const struct sock *sk)

{

	return inet_sk(sk)->inet_dport != inet_sk((struct sock *)msk)->inet_dport;

}



static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)

{

	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
@@ -402,6 +426,12 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb) 


		subflow->mp_join = 1;

		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKRX);



		if (subflow_use_different_dport(mptcp_sk(parent), sk)) {

			pr_debug("synack inet_dport=%d %d",

				 ntohs(inet_sk(sk)->inet_dport),

				 ntohs(inet_sk(parent)->inet_dport));

		}

	} else if (mptcp_check_fallback(sk)) {

fallback:

		mptcp_rcv_space_init(mptcp_sk(parent), sk);
@@ -667,6 +697,14 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, 


			SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKRX);

			tcp_rsk(req)->drop_req = true;



			if (subflow_use_different_sport(owner, sk)) {

				pr_debug("ack inet_sport=%d %d",

					 ntohs(inet_sk(sk)->inet_sport),

					 ntohs(inet_sk((struct sock *)owner)->inet_sport));

				if (!mptcp_pm_sport_in_anno_list(owner, sk))

					goto out;

			}

		}

	}