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Commit 4cde1d2f authored by Eric Dumazet's avatar Eric Dumazet Committed by Greg Kroah-Hartman
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netlink: annotate data races around sk_state 



[ Upstream commit 9b663b5cbb15b494ef132a3c937641c90646eb73 ]

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>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent c64bb854

net/netlink/af_netlink.c

+6 −4
Original line number Diff line number Diff line
@@ -1080,7 +1080,8 @@ 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);
@@ -1104,7 +1105,8 @@ 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));
@@ -1156,8 +1158,8 @@ 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);