Commit 39545023 authored by Matt Johnston's avatar Matt Johnston Committed by Paolo Abeni
Browse files

net: mctp: Prevent duplicate binds 



Disallow bind() calls that have the same arguments as existing bound
sockets.  Previously multiple sockets could bind() to the same
type/local address, with an arbitrary socket receiving matched messages.

This is only a partial fix, a future commit will define precedence order
for MCTP_ADDR_ANY versus specific EID bind(), which are allowed to exist
together.

Signed-off-by: default avatarMatt Johnston <matt@codeconstruct.com.au>
Link: https://patch.msgid.link/20250710-mctp-bind-v4-2-8ec2f6460c56@codeconstruct.com.au


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 3558ab79

net/mctp/af_mctp.c

+23 −3
Original line number Diff line number Diff line
@@ -73,7 +73,6 @@ static int mctp_bind(struct socket *sock, struct sockaddr *addr, int addrlen) 


	lock_sock(sk);



	/* TODO: allow rebind */

	if (sk_hashed(sk)) {

		rc = -EADDRINUSE;

		goto out_release;
@@ -611,15 +610,36 @@ static void mctp_sk_close(struct sock *sk, long timeout) 
static int mctp_sk_hash(struct sock *sk)

{

	struct net *net = sock_net(sk);

	struct sock *existing;

	struct mctp_sock *msk;

	int rc;



	msk = container_of(sk, struct mctp_sock, sk);



	/* Bind lookup runs under RCU, remain live during that. */

	sock_set_flag(sk, SOCK_RCU_FREE);



	mutex_lock(&net->mctp.bind_lock);



	/* Prevent duplicate binds. */

	sk_for_each(existing, &net->mctp.binds) {

		struct mctp_sock *mex =

			container_of(existing, struct mctp_sock, sk);



		if (mex->bind_type == msk->bind_type &&

		    mex->bind_addr == msk->bind_addr &&

		    mex->bind_net == msk->bind_net) {

			rc = -EADDRINUSE;

			goto out;

		}

	}



	sk_add_node_rcu(sk, &net->mctp.binds);

	mutex_unlock(&net->mctp.bind_lock);

	rc = 0;



	return 0;

out:

	mutex_unlock(&net->mctp.bind_lock);

	return rc;

}



static void mctp_sk_unhash(struct sock *sk)