Commit 3549eb08 authored by Matt Johnston's avatar Matt Johnston Committed by Paolo Abeni
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net: mctp: Allow limiting binds to a peer address 



Prior to calling bind() a program may call connect() on a socket to
restrict to a remote peer address.

Using connect() is the normal mechanism to specify a remote network
peer, so we use that here. In MCTP connect() is only used for bound
sockets - send() is not available for MCTP since a tag must be provided
for each message.

The smctp_type must match between connect() and bind() calls.

Signed-off-by: default avatarMatt Johnston <matt@codeconstruct.com.au>
Link: https://patch.msgid.link/20250710-mctp-bind-v4-6-8ec2f6460c56@codeconstruct.com.au


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 1aeed732

include/net/mctp.h

+4 −1
Original line number Diff line number Diff line
@@ -69,7 +69,10 @@ struct mctp_sock { 


	/* bind() params */

	unsigned int	bind_net;

	mctp_eid_t	bind_addr;

	mctp_eid_t	bind_local_addr;

	mctp_eid_t	bind_peer_addr;

	unsigned int	bind_peer_net;

	bool		bind_peer_set;

	__u8		bind_type;



	/* sendmsg()/recvmsg() uses struct sockaddr_mctp_ext */

net/mctp/af_mctp.c

+99 −6
Original line number Diff line number Diff line
@@ -79,7 +79,7 @@ static int mctp_bind(struct socket *sock, struct sockaddr *addr, int addrlen) 
		goto out_release;

	}



	msk->bind_addr = smctp->smctp_addr.s_addr;

	msk->bind_local_addr = smctp->smctp_addr.s_addr;



	/* MCTP_NET_ANY with a specific EID is resolved to the default net

	 * at bind() time.
@@ -87,13 +87,35 @@ static int mctp_bind(struct socket *sock, struct sockaddr *addr, int addrlen) 
	 * lookup time.

	 */

	if (smctp->smctp_network == MCTP_NET_ANY &&

	    msk->bind_addr != MCTP_ADDR_ANY) {

	    msk->bind_local_addr != MCTP_ADDR_ANY) {

		msk->bind_net = mctp_default_net(net);

	} else {

		msk->bind_net = smctp->smctp_network;

	}



	msk->bind_type = smctp->smctp_type & 0x7f; /* ignore the IC bit */

	/* ignore the IC bit */

	smctp->smctp_type &= 0x7f;



	if (msk->bind_peer_set) {

		if (msk->bind_type != smctp->smctp_type) {

			/* Prior connect() had a different type */

			rc = -EINVAL;

			goto out_release;

		}



		if (msk->bind_net == MCTP_NET_ANY) {

			/* Restrict to the network passed to connect() */

			msk->bind_net = msk->bind_peer_net;

		}



		if (msk->bind_net != msk->bind_peer_net) {

			/* connect() had a different net to bind() */

			rc = -EINVAL;

			goto out_release;

		}

	} else {

		msk->bind_type = smctp->smctp_type;

	}



	rc = sk->sk_prot->hash(sk);
@@ -103,6 +125,67 @@ static int mctp_bind(struct socket *sock, struct sockaddr *addr, int addrlen) 
	return rc;

}



/* Used to set a specific peer prior to bind. Not used for outbound

 * connections (Tag Owner set) since MCTP is a datagram protocol.

 */

static int mctp_connect(struct socket *sock, struct sockaddr *addr,

			int addrlen, int flags)

{

	struct sock *sk = sock->sk;

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

	struct net *net = sock_net(&msk->sk);

	struct sockaddr_mctp *smctp;

	int rc;



	if (addrlen != sizeof(*smctp))

		return -EINVAL;



	if (addr->sa_family != AF_MCTP)

		return -EAFNOSUPPORT;



	/* It's a valid sockaddr for MCTP, cast and do protocol checks */

	smctp = (struct sockaddr_mctp *)addr;



	if (!mctp_sockaddr_is_ok(smctp))

		return -EINVAL;



	/* Can't bind by tag */

	if (smctp->smctp_tag)

		return -EINVAL;



	/* IC bit must be unset */

	if (smctp->smctp_type & 0x80)

		return -EINVAL;



	lock_sock(sk);



	if (sk_hashed(sk)) {

		/* bind() already */

		rc = -EADDRINUSE;

		goto out_release;

	}



	if (msk->bind_peer_set) {

		/* connect() already */

		rc = -EADDRINUSE;

		goto out_release;

	}



	msk->bind_peer_set = true;

	msk->bind_peer_addr = smctp->smctp_addr.s_addr;

	msk->bind_type = smctp->smctp_type;

	if (smctp->smctp_network == MCTP_NET_ANY)

		msk->bind_peer_net = mctp_default_net(net);

	else

		msk->bind_peer_net = smctp->smctp_network;



	rc = 0;



out_release:

	release_sock(sk);

	return rc;

}



static int mctp_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)

{

	DECLARE_SOCKADDR(struct sockaddr_mctp *, addr, msg->msg_name);
@@ -546,7 +629,7 @@ static const struct proto_ops mctp_dgram_ops = { 
	.family		= PF_MCTP,

	.release	= mctp_release,

	.bind		= mctp_bind,

	.connect	= sock_no_connect,

	.connect	= mctp_connect,

	.socketpair	= sock_no_socketpair,

	.accept		= sock_no_accept,

	.getname	= sock_no_getname,
@@ -613,6 +696,7 @@ static int mctp_sk_init(struct sock *sk) 


	INIT_HLIST_HEAD(&msk->keys);

	timer_setup(&msk->key_expiry, mctp_sk_expire_keys, 0);

	msk->bind_peer_set = false;

	return 0;

}
@@ -626,12 +710,17 @@ static int mctp_sk_hash(struct sock *sk) 
	struct net *net = sock_net(sk);

	struct sock *existing;

	struct mctp_sock *msk;

	mctp_eid_t remote;

	u32 hash;

	int rc;



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



	hash = mctp_bind_hash(msk->bind_type, msk->bind_addr, MCTP_ADDR_ANY);

	if (msk->bind_peer_set)

		remote = msk->bind_peer_addr;

	else

		remote = MCTP_ADDR_ANY;

	hash = mctp_bind_hash(msk->bind_type, msk->bind_local_addr, remote);



	mutex_lock(&net->mctp.bind_lock);
@@ -640,8 +729,12 @@ static int mctp_sk_hash(struct sock *sk) 
		struct mctp_sock *mex =

			container_of(existing, struct mctp_sock, sk);



		bool same_peer = (mex->bind_peer_set && msk->bind_peer_set &&

				  mex->bind_peer_addr == msk->bind_peer_addr) ||

				 (!mex->bind_peer_set && !msk->bind_peer_set);



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

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

		    mex->bind_local_addr == msk->bind_local_addr && same_peer &&

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

			rc = -EADDRINUSE;

			goto out;

net/mctp/route.c

+5 −1
Original line number Diff line number Diff line
@@ -65,7 +65,11 @@ static struct mctp_sock *mctp_lookup_bind_details(struct net *net, 
		if (msk->bind_type != type)

			continue;



		if (!mctp_address_matches(msk->bind_addr, dest))

		if (msk->bind_peer_set &&

		    !mctp_address_matches(msk->bind_peer_addr, src))

			continue;



		if (!mctp_address_matches(msk->bind_local_addr, dest))

			continue;



		return msk;