From 9b663b5cbb15b494ef132a3c937641c90646eb73 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 20 Jan 2023 12:59:55 +0000 Subject: [PATCH] netlink: annotate data races around sk_state netlink_getsockbyportid() reads sk_state while a concurrent netlink_connect() can change its value. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Signed-off-by: Jakub Kicinski --- net/netlink/af_netlink.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index b5b8c6a..c642776 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -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); -- 2.7.4