tcp: Fix data-races around sysctl_tcp_l3mdev_accept.

[ Upstream commit 08a75f10679470552a3a443f9aefd1399604d31d ]

While reading sysctl_tcp_l3mdev_accept, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.

Fixes: 6dd9a14e92e5 ("net: Allow accepted sockets to be bound to l3mdev domain")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index 98e1ec1a14f0382d1f4f8e85fe5ac2a056d2d6bc..749bb1e460871a5ddbeb1c52ccefdac54209bbef 100644 (file)
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -207,7 +207,7 @@ static inline bool inet_sk_bound_dev_eq(struct net *net, int bound_dev_if,
                                        int dif, int sdif)
 {
 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
-       return inet_bound_dev_eq(!!net->ipv4.sysctl_tcp_l3mdev_accept,
+       return inet_bound_dev_eq(!!READ_ONCE(net->ipv4.sysctl_tcp_l3mdev_accept),
                                 bound_dev_if, dif, sdif);
 #else
        return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);

diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index e71827aa2dfb1643cf862beef869f0a19bff5098..c307a547d2cb41940620b0502b810186a1c23ba2 100644 (file)
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -121,7 +121,7 @@ static inline int inet_request_bound_dev_if(const struct sock *sk,
 #ifdef CONFIG_NET_L3_MASTER_DEV
        struct net *net = sock_net(sk);
 
-       if (!bound_dev_if && net->ipv4.sysctl_tcp_l3mdev_accept)
+       if (!bound_dev_if && READ_ONCE(net->ipv4.sysctl_tcp_l3mdev_accept))
                return l3mdev_master_ifindex_by_index(net, skb->skb_iif);
 #endif
 
@@ -133,7 +133,7 @@ static inline int inet_sk_bound_l3mdev(const struct sock *sk)
 #ifdef CONFIG_NET_L3_MASTER_DEV
        struct net *net = sock_net(sk);
 
-       if (!net->ipv4.sysctl_tcp_l3mdev_accept)
+       if (!READ_ONCE(net->ipv4.sysctl_tcp_l3mdev_accept))
                return l3mdev_master_ifindex_by_index(net,
                                                      sk->sk_bound_dev_if);
 #endif