[PATCH v2 net-next 1/3] inet: ping: check sock_net() in ping_get_port() and ping_lookup()

[Eric Dumazet <edumazet@google.com>]

We need to check socket netns before considering them in ping_get_port().
Otherwise, one malicious netns could 'consume' all ports.

Add corresponding check in ping_lookup().

Fixes: c319b4d76b9e ("net: ipv4: add IPPROTO_ICMP socket kind")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
---
v2: added change to ping_lookup().
v1: https://lore.kernel.org/netdev/CANn89iKF+DFQQyNJoYA2U-wf4QDPOUG2yNOd8fSu45hQ+TxJ5Q@mail.gmail.com/T/#u

 net/ipv4/ping.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index f119da68fc301be00719213ad33615b6754e6272..74a0beddfcc41d8ba17792a11a9d027c9d590bac 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -77,6 +77,7 @@ static inline struct hlist_head *ping_hashslot(struct ping_table *table,
 
 int ping_get_port(struct sock *sk, unsigned short ident)
 {
+	struct net *net = sock_net(sk);
 	struct inet_sock *isk, *isk2;
 	struct hlist_head *hlist;
 	struct sock *sk2 = NULL;
@@ -90,9 +91,10 @@ int ping_get_port(struct sock *sk, unsigned short ident)
 		for (i = 0; i < (1L << 16); i++, result++) {
 			if (!result)
 				result++; /* avoid zero */
-			hlist = ping_hashslot(&ping_table, sock_net(sk),
-					    result);
+			hlist = ping_hashslot(&ping_table, net, result);
 			sk_for_each(sk2, hlist) {
+				if (!net_eq(sock_net(sk2), net))
+					continue;
 				isk2 = inet_sk(sk2);
 
 				if (isk2->inet_num == result)
@@ -108,8 +110,10 @@ int ping_get_port(struct sock *sk, unsigned short ident)
 		if (i >= (1L << 16))
 			goto fail;
 	} else {
-		hlist = ping_hashslot(&ping_table, sock_net(sk), ident);
+		hlist = ping_hashslot(&ping_table, net, ident);
 		sk_for_each(sk2, hlist) {
+			if (!net_eq(sock_net(sk2), net))
+				continue;
 			isk2 = inet_sk(sk2);
 
 			/* BUG? Why is this reuse and not reuseaddr? ping.c
@@ -129,7 +133,7 @@ int ping_get_port(struct sock *sk, unsigned short ident)
 		pr_debug("was not hashed\n");
 		sk_add_node_rcu(sk, hlist);
 		sock_set_flag(sk, SOCK_RCU_FREE);
-		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
+		sock_prot_inuse_add(net, sk->sk_prot, 1);
 	}
 	spin_unlock(&ping_table.lock);
 	return 0;
@@ -188,6 +192,8 @@ static struct sock *ping_lookup(struct net *net, struct sk_buff *skb, u16 ident)
 	}
 
 	sk_for_each_rcu(sk, hslot) {
+		if (!net_eq(sock_net(sk), net))
+			continue;
 		isk = inet_sk(sk);
 
 		pr_debug("iterate\n");
-- 
2.51.0.268.g9569e192d0-goog