Re: memory leak in ipv6_sock_ac_join ( 5.8.0-rc6+)

[Cong Wang]

On Thu, Jul 23, 2020 at 5:06 PM \xcH3332\ <ch333...@gmail.com> wrote:
>
> Hi,
>
> SYZKALLER found the following Memory Leak

Thanks for your report!

Can you test the attached patch? I only did compile test as I don't
have an environment to run syz programs.

diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index fdb07105384c..8418b7d38468 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -274,6 +274,7 @@ int ipv6_sock_ac_join(struct sock *sk, int ifindex,
 		      const struct in6_addr *addr);
 int ipv6_sock_ac_drop(struct sock *sk, int ifindex,
 		      const struct in6_addr *addr);
+void __ipv6_sock_ac_close(struct sock *sk);
 void ipv6_sock_ac_close(struct sock *sk);
 
 int __ipv6_dev_ac_inc(struct inet6_dev *idev, const struct in6_addr *addr);
diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
index 893261230ffc..dacdea7fcb62 100644
--- a/net/ipv6/anycast.c
+++ b/net/ipv6/anycast.c
@@ -183,7 +183,7 @@ int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
 	return 0;
 }
 
-void ipv6_sock_ac_close(struct sock *sk)
+void __ipv6_sock_ac_close(struct sock *sk)
 {
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	struct net_device *dev = NULL;
@@ -191,10 +191,7 @@ void ipv6_sock_ac_close(struct sock *sk)
 	struct net *net = sock_net(sk);
 	int	prev_index;
 
-	if (!np->ipv6_ac_list)
-		return;
-
-	rtnl_lock();
+	ASSERT_RTNL();
 	pac = np->ipv6_ac_list;
 	np->ipv6_ac_list = NULL;
 
@@ -211,6 +208,16 @@ void ipv6_sock_ac_close(struct sock *sk)
 		sock_kfree_s(sk, pac, sizeof(*pac));
 		pac = next;
 	}
+}
+
+void ipv6_sock_ac_close(struct sock *sk)
+{
+	struct ipv6_pinfo *np = inet6_sk(sk);
+
+	if (!np->ipv6_ac_list)
+		return;
+	rtnl_lock();
+	__ipv6_sock_ac_close(sk);
 	rtnl_unlock();
 }
 
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 20576e87a5f7..76f9e41859a2 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -240,6 +240,7 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
 
 			fl6_free_socklist(sk);
 			__ipv6_sock_mc_close(sk);
+			__ipv6_sock_ac_close(sk);
 
 			/*
 			 * Sock is moving from IPv6 to IPv4 (sk_prot), so