Commit 9b663b5c authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

netlink: annotate data races around sk_state 



netlink_getsockbyportid() reads sk_state while a concurrent
netlink_connect() can change its value.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 004db64d

net/netlink/af_netlink.c

+6 −4
Original line number Diff line number Diff line
@@ -1098,7 +1098,8 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr, 
		return -EINVAL;



	if (addr->sa_family == AF_UNSPEC) {

		sk->sk_state	= NETLINK_UNCONNECTED;

		/* paired with READ_ONCE() in netlink_getsockbyportid() */

		WRITE_ONCE(sk->sk_state, NETLINK_UNCONNECTED);

		/* dst_portid and dst_group can be read locklessly */

		WRITE_ONCE(nlk->dst_portid, 0);

		WRITE_ONCE(nlk->dst_group, 0);
@@ -1122,7 +1123,8 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr, 
		err = netlink_autobind(sock);



	if (err == 0) {

		sk->sk_state	= NETLINK_CONNECTED;

		/* paired with READ_ONCE() in netlink_getsockbyportid() */

		WRITE_ONCE(sk->sk_state, NETLINK_CONNECTED);

		/* dst_portid and dst_group can be read locklessly */

		WRITE_ONCE(nlk->dst_portid, nladdr->nl_pid);

		WRITE_ONCE(nlk->dst_group, ffs(nladdr->nl_groups));
@@ -1174,8 +1176,8 @@ static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid) 


	/* Don't bother queuing skb if kernel socket has no input function */

	nlk = nlk_sk(sock);

	/* dst_portid can be changed in netlink_connect() */

	if (sock->sk_state == NETLINK_CONNECTED &&

	/* dst_portid and sk_state can be changed in netlink_connect() */

	if (READ_ONCE(sock->sk_state) == NETLINK_CONNECTED &&

	    READ_ONCE(nlk->dst_portid) != nlk_sk(ssk)->portid) {

		sock_put(sock);

		return ERR_PTR(-ECONNREFUSED);