Unverified Commit 9bedee7c authored by Alexander Mikhalitsyn's avatar Alexander Mikhalitsyn Committed by Christian Brauner
Browse files

af_unix: rework unix_maybe_add_creds() to allow sleep 



As a preparation for the next patches we need to allow sleeping
in unix_maybe_add_creds() and also return err. Currently, we can't do
that as unix_maybe_add_creds() is being called under unix_state_lock().
There is no need for this, really. So let's move call sites of
this helper a bit and do necessary function signature changes.

Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Simon Horman <horms@kernel.org>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Kuniyuki Iwashima <kuniyu@google.com>
Cc: Lennart Poettering <mzxreary@0pointer.de>
Cc: Luca Boccassi <bluca@debian.org>
Cc: David Rheinsberg <david@readahead.eu>
Signed-off-by: default avatarAlexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Link: https://lore.kernel.org/20250703222314.309967-2-aleksandr.mikhalitsyn@canonical.com


Reviewed-by: default avatarChristian Brauner <brauner@kernel.org>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 86767306

net/unix/af_unix.c

+25 −7
Original line number Diff line number Diff line
@@ -1955,21 +1955,30 @@ static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool sen 
	return err;

}



/*

/**

 * unix_maybe_add_creds() - Adds current task uid/gid and struct pid to skb if needed.

 * @skb: skb to attach creds to.

 * @sk: Sender sock.

 * @other: Receiver sock.

 *

 * Some apps rely on write() giving SCM_CREDENTIALS

 * We include credentials if source or destination socket

 * asserted SOCK_PASSCRED.

 *

 * Return: On success zero, on error a negative error code is returned.

 */

static void unix_maybe_add_creds(struct sk_buff *skb, const struct sock *sk,

static int unix_maybe_add_creds(struct sk_buff *skb, const struct sock *sk,

				const struct sock *other)

{

	if (UNIXCB(skb).pid)

		return;

		return 0;



	if (unix_may_passcred(sk) || unix_may_passcred(other)) {

		UNIXCB(skb).pid = get_pid(task_tgid(current));

		current_uid_gid(&UNIXCB(skb).uid, &UNIXCB(skb).gid);

	}



	return 0;

}



static bool unix_skb_scm_eq(struct sk_buff *skb,
@@ -2104,6 +2113,10 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, 
		goto out_sock_put;

	}



	err = unix_maybe_add_creds(skb, sk, other);

	if (err)

		goto out_sock_put;



restart:

	sk_locked = 0;

	unix_state_lock(other);
@@ -2212,7 +2225,6 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, 
	if (sock_flag(other, SOCK_RCVTSTAMP))

		__net_timestamp(skb);



	unix_maybe_add_creds(skb, sk, other);

	scm_stat_add(other, skb);

	skb_queue_tail(&other->sk_receive_queue, skb);

	unix_state_unlock(other);
@@ -2256,6 +2268,10 @@ static int queue_oob(struct sock *sk, struct msghdr *msg, struct sock *other, 
	if (err < 0)

		goto out;



	err = unix_maybe_add_creds(skb, sk, other);

	if (err)

		goto out;



	skb_put(skb, 1);

	err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, 1);
@@ -2275,7 +2291,6 @@ static int queue_oob(struct sock *sk, struct msghdr *msg, struct sock *other, 
		goto out_unlock;

	}



	unix_maybe_add_creds(skb, sk, other);

	scm_stat_add(other, skb);



	spin_lock(&other->sk_receive_queue.lock);
@@ -2369,6 +2384,10 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, 


		fds_sent = true;



		err = unix_maybe_add_creds(skb, sk, other);

		if (err)

			goto out_free;



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

			skb->ip_summed = CHECKSUM_UNNECESSARY;

			err = skb_splice_from_iter(skb, &msg->msg_iter, size,
@@ -2399,7 +2418,6 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, 
			goto out_free;

		}



		unix_maybe_add_creds(skb, sk, other);

		scm_stat_add(other, skb);

		skb_queue_tail(&other->sk_receive_queue, skb);

		unix_state_unlock(other);