Commit 963b7895 authored by Paolo Abeni's avatar Paolo Abeni
Browse files

Merge branch 'af_unix-prepare-for-skb-drop-reason' 

Kuniyuki Iwashima says:

====================
af_unix: Prepare for skb drop reason.

This is a prep series and cleans up error paths in the following
functions

  * unix_stream_connect()
  * unix_stream_sendmsg()
  * unix_dgram_sendmsg()

to make it easy to add skb drop reason for AF_UNIX, which seems to
have a potential user.

https://lore.kernel.org/netdev/CAAf2ycmZHti95WaBR3s+L5Epm1q7sXmvZ-EqCK=-oZj=45tOwQ@mail.gmail.com/

v1: https://lore.kernel.org/netdev/20241206052607.1197-1-kuniyu@amazon.com/
====================

Link: https://patch.msgid.link/20241213110850.25453-1-kuniyu@amazon.com


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parents a14a4290 bf61ffeb

net/unix/af_unix.c

+96 −100
Original line number Diff line number Diff line
@@ -286,14 +286,9 @@ static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb) 
}

#endif /* CONFIG_SECURITY_NETWORK */



static inline int unix_our_peer(struct sock *sk, struct sock *osk)

{

	return unix_peer(osk) == sk;

}



static inline int unix_may_send(struct sock *sk, struct sock *osk)

{

	return unix_peer(osk) == NULL || unix_our_peer(sk, osk);

	return !unix_peer(osk) || unix_peer(osk) == sk;

}



static inline int unix_recvq_full_lockless(const struct sock *sk)
@@ -1563,32 +1558,30 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, 
	timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);



	/* First of all allocate resources.

	   If we will make it after state is locked,

	   we will have to recheck all again in any case.

	 * If we will make it after state is locked,

	 * we will have to recheck all again in any case.

	 */



	/* create new sock for complete connection */

	newsk = unix_create1(net, NULL, 0, sock->type);

	if (IS_ERR(newsk)) {

		err = PTR_ERR(newsk);

		newsk = NULL;

		goto out;

	}



	err = -ENOMEM;



	/* Allocate skb for sending to listening sock */

	skb = sock_wmalloc(newsk, 1, 0, GFP_KERNEL);

	if (skb == NULL)

		goto out;

	if (!skb) {

		err = -ENOMEM;

		goto out_free_sk;

	}



restart:

	/*  Find listening sock. */

	other = unix_find_other(net, sunaddr, addr_len, sk->sk_type);

	if (IS_ERR(other)) {

		err = PTR_ERR(other);

		other = NULL;

		goto out;

		goto out_free_skb;

	}



	unix_state_lock(other);
@@ -1600,23 +1593,25 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, 
		goto restart;

	}



	if (other->sk_state != TCP_LISTEN ||

	    other->sk_shutdown & RCV_SHUTDOWN) {

		err = -ECONNREFUSED;

	if (other->sk_state != TCP_LISTEN)

		goto out_unlock;

	if (other->sk_shutdown & RCV_SHUTDOWN)

		goto out_unlock;

	}



	if (unix_recvq_full_lockless(other)) {

		if (!timeo) {

			err = -EAGAIN;

		if (!timeo)

			goto out_unlock;

		}



		timeo = unix_wait_for_peer(other, timeo);

		sock_put(other);



		err = sock_intr_errno(timeo);

		if (signal_pending(current))

			goto out;

		sock_put(other);

			goto out_free_skb;



		goto restart;

	}
@@ -1701,15 +1696,13 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, 
	return 0;



out_unlock:

	if (other)

	unix_state_unlock(other);



out:

	sock_put(other);

out_free_skb:

	kfree_skb(skb);

	if (newsk)

out_free_sk:

	unix_release_sock(newsk, 0);

	if (other)

		sock_put(other);

out:

	return err;

}
@@ -1964,7 +1957,6 @@ static void scm_stat_del(struct sock *sk, struct sk_buff *skb) 
static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,

			      size_t len)

{

	DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);

	struct sock *sk = sock->sk, *other = NULL;

	struct unix_sock *u = unix_sk(sk);

	struct scm_cookie scm;
@@ -1980,12 +1972,13 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, 


	wait_for_unix_gc(scm.fp);



	if (msg->msg_flags & MSG_OOB) {

		err = -EOPNOTSUPP;

	if (msg->msg_flags&MSG_OOB)

		goto out;

	}



	if (msg->msg_namelen) {

		err = unix_validate_addr(sunaddr, msg->msg_namelen);

		err = unix_validate_addr(msg->msg_name, msg->msg_namelen);

		if (err)

			goto out;
@@ -1995,12 +1988,6 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, 
							    NULL);

		if (err)

			goto out;

	} else {

		sunaddr = NULL;

		err = -ENOTCONN;

		other = unix_peer_get(sk);

		if (!other)

			goto out;

	}



	if ((test_bit(SOCK_PASSCRED, &sock->flags) ||
@@ -2011,9 +1998,10 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, 
			goto out;

	}



	if (len > READ_ONCE(sk->sk_sndbuf) - 32) {

		err = -EMSGSIZE;

	if (len > READ_ONCE(sk->sk_sndbuf) - 32)

		goto out;

	}



	if (len > SKB_MAX_ALLOC) {

		data_len = min_t(size_t,
@@ -2027,7 +2015,7 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, 
	skb = sock_alloc_send_pskb(sk, len - data_len, data_len,

				   msg->msg_flags & MSG_DONTWAIT, &err,

				   PAGE_ALLOC_COSTLY_ORDER);

	if (skb == NULL)

	if (!skb)

		goto out;



	err = unix_scm_to_skb(&scm, skb, true);
@@ -2043,17 +2031,18 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, 


	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);



restart:

	if (!other) {

		err = -ECONNRESET;

		if (sunaddr == NULL)

			goto out_free;



		other = unix_find_other(sock_net(sk), sunaddr, msg->msg_namelen,

					sk->sk_type);

	if (msg->msg_namelen) {

lookup:

		other = unix_find_other(sock_net(sk), msg->msg_name,

					msg->msg_namelen, sk->sk_type);

		if (IS_ERR(other)) {

			err = PTR_ERR(other);

			other = NULL;

			goto out_free;

		}

	} else {

		other = unix_peer_get(sk);

		if (!other) {

			err = -ENOTCONN;

			goto out_free;

		}

	}
@@ -2061,36 +2050,37 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, 
	if (sk_filter(other, skb) < 0) {

		/* Toss the packet but do not return any error to the sender */

		err = len;

		goto out_free;

		goto out_sock_put;

	}



restart:

	sk_locked = 0;

	unix_state_lock(other);

restart_locked:



	if (!unix_may_send(sk, other)) {

		err = -EPERM;

	if (!unix_may_send(sk, other))

		goto out_unlock;

	}



	if (unlikely(sock_flag(other, SOCK_DEAD))) {

		/*

		 *	Check with 1003.1g - what should

		 *	datagram error

		 */

		unix_state_unlock(other);

		sock_put(other);

		/* Check with 1003.1g - what should datagram error */



		if (!sk_locked)

			unix_state_lock(sk);

		unix_state_unlock(other);



		err = 0;

		if (sk->sk_type == SOCK_SEQPACKET) {

			/* We are here only when racing with unix_release_sock()

			 * is clearing @other. Never change state to TCP_CLOSE

			 * unlike SOCK_DGRAM wants.

			 */

			unix_state_unlock(sk);

			err = -EPIPE;

		} else if (unix_peer(sk) == other) {

			goto out_sock_put;

		}



		if (!sk_locked)

			unix_state_lock(sk);



		if (unix_peer(sk) == other) {

			unix_peer(sk) = NULL;

			unix_dgram_peer_wake_disconnect_wakeup(sk, other);
@@ -2100,19 +2090,23 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, 
			unix_dgram_disconnected(sk, other);

			sock_put(other);

			err = -ECONNREFUSED;

		} else {

			goto out_sock_put;

		}



		unix_state_unlock(sk);



		if (!msg->msg_namelen) {

			err = -ECONNRESET;

			goto out_sock_put;

		}



		other = NULL;

		if (err)

			goto out_free;

		goto restart;

		goto lookup;

	}



	if (other->sk_shutdown & RCV_SHUTDOWN) {

		err = -EPIPE;

	if (other->sk_shutdown & RCV_SHUTDOWN)

		goto out_unlock;

	}



	if (sk->sk_type != SOCK_SEQPACKET) {

		err = security_unix_may_send(sk->sk_socket, other->sk_socket);
@@ -2132,7 +2126,7 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, 


			err = sock_intr_errno(timeo);

			if (signal_pending(current))

				goto out_free;

				goto out_sock_put;



			goto restart;

		}
@@ -2173,11 +2167,11 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, 
	if (sk_locked)

		unix_state_unlock(sk);

	unix_state_unlock(other);

out_sock_put:

	sock_put(other);

out_free:

	kfree_skb(skb);

out:

	if (other)

		sock_put(other);

	scm_destroy(&scm);

	return err;

}
@@ -2256,8 +2250,8 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, 


	wait_for_unix_gc(scm.fp);



	err = -EOPNOTSUPP;

	if (msg->msg_flags & MSG_OOB) {

		err = -EOPNOTSUPP;

#if IS_ENABLED(CONFIG_AF_UNIX_OOB)

		if (len)

			len--;
@@ -2270,14 +2264,20 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, 
		err = READ_ONCE(sk->sk_state) == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;

		goto out_err;

	} else {

		err = -ENOTCONN;

		other = unix_peer(sk);

		if (!other)

		if (!other) {

			err = -ENOTCONN;

			goto out_err;

		}

	}



	if (READ_ONCE(sk->sk_shutdown) & SEND_SHUTDOWN) {

		if (!(msg->msg_flags & MSG_NOSIGNAL))

			send_sig(SIGPIPE, current, 0);



	if (READ_ONCE(sk->sk_shutdown) & SEND_SHUTDOWN)

		goto pipe_err;

		err = -EPIPE;

		goto out_err;

	}



	while (sent < len) {

		size = len - sent;
@@ -2306,20 +2306,18 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, 


		/* Only send the fds in the first buffer */

		err = unix_scm_to_skb(&scm, skb, !fds_sent);

		if (err < 0) {

			kfree_skb(skb);

			goto out_err;

		}

		if (err < 0)

			goto out_free;



		fds_sent = true;



		if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) {

			skb->ip_summed = CHECKSUM_UNNECESSARY;

			err = skb_splice_from_iter(skb, &msg->msg_iter, size,

						   sk->sk_allocation);

			if (err < 0) {

				kfree_skb(skb);

				goto out_err;

			}

			if (err < 0)

				goto out_free;



			size = err;

			refcount_add(size, &sk->sk_wmem_alloc);

		} else {
@@ -2327,17 +2325,15 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, 
			skb->data_len = data_len;

			skb->len = size;

			err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);

			if (err) {

				kfree_skb(skb);

				goto out_err;

			}

			if (err)

				goto out_free;

		}



		unix_state_lock(other);



		if (sock_flag(other, SOCK_DEAD) ||

		    (other->sk_shutdown & RCV_SHUTDOWN))

			goto pipe_err_free;

			goto out_pipe;



		maybe_add_creds(skb, sock, other);

		scm_stat_add(other, skb);
@@ -2360,13 +2356,13 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, 


	return sent;



pipe_err_free:

out_pipe:

	unix_state_unlock(other);

	kfree_skb(skb);

pipe_err:

	if (sent == 0 && !(msg->msg_flags&MSG_NOSIGNAL))

	if (!sent && !(msg->msg_flags & MSG_NOSIGNAL))

		send_sig(SIGPIPE, current, 0);

	err = -EPIPE;

out_free:

	kfree_skb(skb);

out_err:

	scm_destroy(&scm);

	return sent ? : err;