From 5bc56388c74f0e64b32e343ea603609b146dcb96 Mon Sep 17 00:00:00 2001 From: Geliang Tang Date: Mon, 1 Feb 2021 15:09:15 -0800 Subject: [PATCH] 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: Geliang Tang Signed-off-by: Mat Martineau Signed-off-by: Jakub Kicinski --- net/mptcp/pm_netlink.c | 23 ++++++++++++++++++++++- net/mptcp/protocol.h | 1 + net/mptcp/subflow.c | 38 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 61 insertions(+), 1 deletion(-) diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index b71701a743a4..54f0ca73e68a 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -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); diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 4e071d9264dc..1cc7948a1826 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -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); diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 94926ab74d48..ebfbf6a9b669 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -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 @@ again: 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 @@ create_child: 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; + } } } -- 2.20.1