Commit f3c7a6e0 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'mptcp-cope-with-syncookie-on-MP_JOINs' 



Paolo Abeni says:

====================
mptcp: cope with syncookie on MP_JOINs

Currently syncookies on MP_JOIN connections are not handled correctly: the
connections fallback to TCP and are kept alive instead of resetting them at
fallback time.

The first patch propagates the required information up to syn_recv_sock time,
and the 2nd patch addresses the unifying the error path for all MP_JOIN
requests.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 5eea3a63 9e365ff5

net/mptcp/protocol.h

+1 −0
Original line number Diff line number Diff line
@@ -249,6 +249,7 @@ struct mptcp_subflow_request_sock { 
	u64	thmac;

	u32	local_nonce;

	u32	remote_nonce;

	struct mptcp_sock	*msk;

};



static inline struct mptcp_subflow_request_sock *

net/mptcp/subflow.c

+27 −30
Original line number Diff line number Diff line
@@ -69,6 +69,9 @@ static void subflow_req_destructor(struct request_sock *req) 


	pr_debug("subflow_req=%p", subflow_req);



	if (subflow_req->msk)

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



	if (subflow_req->mp_capable)

		mptcp_token_destroy_request(subflow_req->token);

	tcp_request_sock_ops.destructor(req);
@@ -86,7 +89,7 @@ static void subflow_generate_hmac(u64 key1, u64 key2, u32 nonce1, u32 nonce2, 
}



/* validate received token and create truncated hmac and nonce for SYN-ACK */

static bool subflow_token_join_request(struct request_sock *req,

static struct mptcp_sock *subflow_token_join_request(struct request_sock *req,

						     const struct sk_buff *skb)

{

	struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
@@ -97,13 +100,13 @@ static bool subflow_token_join_request(struct request_sock *req, 
	msk = mptcp_token_get_sock(subflow_req->token);

	if (!msk) {

		SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINNOTOKEN);

		return false;

		return NULL;

	}



	local_id = mptcp_pm_get_local_id(msk, (struct sock_common *)req);

	if (local_id < 0) {

		sock_put((struct sock *)msk);

		return false;

		return NULL;

	}

	subflow_req->local_id = local_id;
@@ -114,9 +117,7 @@ static bool subflow_token_join_request(struct request_sock *req, 
			      subflow_req->remote_nonce, hmac);



	subflow_req->thmac = get_unaligned_be64(hmac);



	sock_put((struct sock *)msk);

	return true;

	return msk;

}



static void subflow_init_req(struct request_sock *req,
@@ -133,6 +134,7 @@ static void subflow_init_req(struct request_sock *req, 


	subflow_req->mp_capable = 0;

	subflow_req->mp_join = 0;

	subflow_req->msk = NULL;



#ifdef CONFIG_TCP_MD5SIG

	/* no MPTCP if MD5SIG is enabled on this socket or we may run out of
@@ -166,12 +168,9 @@ static void subflow_init_req(struct request_sock *req, 
		subflow_req->remote_id = mp_opt.join_id;

		subflow_req->token = mp_opt.token;

		subflow_req->remote_nonce = mp_opt.nonce;

		pr_debug("token=%u, remote_nonce=%u", subflow_req->token,

			 subflow_req->remote_nonce);

		if (!subflow_token_join_request(req, skb)) {

			subflow_req->mp_join = 0;

			// @@ need to trigger RST

		}

		subflow_req->msk = subflow_token_join_request(req, skb);

		pr_debug("token=%u, remote_nonce=%u msk=%p", subflow_req->token,

			 subflow_req->remote_nonce, subflow_req->msk);

	}

}
@@ -354,10 +353,9 @@ static bool subflow_hmac_valid(const struct request_sock *req, 
	const struct mptcp_subflow_request_sock *subflow_req;

	u8 hmac[SHA256_DIGEST_SIZE];

	struct mptcp_sock *msk;

	bool ret;



	subflow_req = mptcp_subflow_rsk(req);

	msk = mptcp_token_get_sock(subflow_req->token);

	msk = subflow_req->msk;

	if (!msk)

		return false;
@@ -365,12 +363,7 @@ static bool subflow_hmac_valid(const struct request_sock *req, 
			      subflow_req->remote_nonce,

			      subflow_req->local_nonce, hmac);



	ret = true;

	if (crypto_memneq(hmac, mp_opt->hmac, MPTCPOPT_HMAC_LEN))

		ret = false;



	sock_put((struct sock *)msk);

	return ret;

	return !crypto_memneq(hmac, mp_opt->hmac, MPTCPOPT_HMAC_LEN);

}



static void mptcp_sock_destruct(struct sock *sk)
@@ -438,22 +431,25 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, 
	struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk);

	struct mptcp_subflow_request_sock *subflow_req;

	struct mptcp_options_received mp_opt;

	bool fallback_is_fatal = false;

	bool fallback, fallback_is_fatal;

	struct sock *new_msk = NULL;

	bool fallback = false;

	struct sock *child;



	pr_debug("listener=%p, req=%p, conn=%p", listener, req, listener->conn);



	/* we need later a valid 'mp_capable' value even when options are not

	 * parsed

	/* After child creation we must look for 'mp_capable' even when options

	 * are not parsed

	 */

	mp_opt.mp_capable = 0;

	if (tcp_rsk(req)->is_mptcp == 0)



	/* hopefully temporary handling for MP_JOIN+syncookie */

	subflow_req = mptcp_subflow_rsk(req);

	fallback_is_fatal = subflow_req->mp_join;

	fallback = !tcp_rsk(req)->is_mptcp;

	if (fallback)

		goto create_child;



	/* if the sk is MP_CAPABLE, we try to fetch the client key */

	subflow_req = mptcp_subflow_rsk(req);

	if (subflow_req->mp_capable) {

		if (TCP_SKB_CB(skb)->seq != subflow_req->ssn_offset + 1) {

			/* here we can receive and accept an in-window,
@@ -474,12 +470,11 @@ create_msk: 
		if (!new_msk)

			fallback = true;

	} else if (subflow_req->mp_join) {

		fallback_is_fatal = true;

		mptcp_get_options(skb, &mp_opt);

		if (!mp_opt.mp_join ||

		    !subflow_hmac_valid(req, &mp_opt)) {

			SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC);

			return NULL;

			fallback = true;

		}

	}
@@ -522,10 +517,12 @@ create_child: 
		} else if (ctx->mp_join) {

			struct mptcp_sock *owner;



			owner = mptcp_token_get_sock(ctx->token);

			owner = subflow_req->msk;

			if (!owner)

				goto dispose_child;



			/* move the msk reference ownership to the subflow */

			subflow_req->msk = NULL;

			ctx->conn = (struct sock *)owner;

			if (!mptcp_finish_join(child))

				goto dispose_child;

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