[PATCH v2 net-next 3/3] inet: ping: make ping_port_rover per netns

[Eric Dumazet <edumazet@google.com>]

Provide isolation between netns for ping idents.

Randomize initial ping_port_rover value at netns creation.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
---
 include/net/netns/ipv4.h |  1 +
 net/ipv4/ping.c          | 10 +++++-----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 6373e3f17da84ebc5c11058763932e595f0fd205..54a7d187f62a2e995076e85f1e6b2fd70f84b2c1 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -251,6 +251,7 @@ struct netns_ipv4 {
 	int sysctl_igmp_qrv;
 
 	struct ping_group_range ping_group_range;
+	u16			ping_port_rover;
 
 	atomic_t dev_addr_genid;
 
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 75e1b0f5c697653e79166fde5f312f46b471344a..98ccd4f9ed657d2bb9c013932d0c678f2b38a746 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -58,8 +58,6 @@ static struct ping_table ping_table;
 struct pingv6_ops pingv6_ops;
 EXPORT_SYMBOL_GPL(pingv6_ops);
 
-static u16 ping_port_rover;
-
 static inline u32 ping_hashfn(const struct net *net, u32 num, u32 mask)
 {
 	u32 res = (num + net_hash_mix(net)) & mask;
@@ -84,12 +82,12 @@ int ping_get_port(struct sock *sk, unsigned short ident)
 	isk = inet_sk(sk);
 	spin_lock(&ping_table.lock);
 	if (ident == 0) {
+		u16 result = net->ipv4.ping_port_rover + 1;
 		u32 i;
-		u16 result = ping_port_rover + 1;
 
 		for (i = 0; i < (1L << 16); i++, result++) {
 			if (!result)
-				result++; /* avoid zero */
+				continue; /* avoid zero */
 			hlist = ping_hashslot(&ping_table, net, result);
 			sk_for_each(sk2, hlist) {
 				if (!net_eq(sock_net(sk2), net))
@@ -101,7 +99,7 @@ int ping_get_port(struct sock *sk, unsigned short ident)
 			}
 
 			/* found */
-			ping_port_rover = ident = result;
+			net->ipv4.ping_port_rover = ident = result;
 			break;
 next_port:
 			;
@@ -1146,6 +1144,8 @@ static int __net_init ping_v4_proc_init_net(struct net *net)
 	if (!proc_create_net("icmp", 0444, net->proc_net, &ping_v4_seq_ops,
 			sizeof(struct ping_iter_state)))
 		return -ENOMEM;
+
+	net->ipv4.ping_port_rover = get_random_u16();
 	return 0;
 }
 
-- 
2.51.0.268.g9569e192d0-goog