On Tue, Jun 06, 2023 at 03:57:35PM +0200, Mirsad Todorovac wrote:
diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c index c4835dbdfcff..c1d81c49b775 100644 --- a/net/ipv6/ping.c +++ b/net/ipv6/ping.c @@ -73,6 +73,10 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) struct rt6_info *rt; struct pingfakehdr pfh; struct ipcm6_cookie ipc6;
struct net *net = sock_net(sk);struct net_device *dev = NULL;struct net_device *mdev = NULL;struct net_device *bdev = NULL; err = ping_common_sendmsg(AF_INET6, msg, len, &user_icmph, sizeof(user_icmph));@@ -111,10 +115,26 @@ static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) else if (!oif) oif = np->ucast_oif;
if (oif) {rcu_read_lock();dev = dev_get_by_index_rcu(net, oif);rcu_read_unlock();
You can't assume '*dev' is still valid after rcu_read_unlock() unless you hold a reference on it.
rtnl_lock();mdev = netdev_master_upper_dev_get(dev);rtnl_unlock();
Because of that, 'dev' might have already disappeared at the time netdev_master_upper_dev_get() is called. So it may dereference an invalid pointer here.
}if (sk->sk_bound_dev_if) {rcu_read_lock();bdev = dev_get_by_index_rcu(net, sk->sk_bound_dev_if);rcu_read_unlock();}addr_type = ipv6_addr_type(daddr); if ((__ipv6_addr_needs_scope_id(addr_type) && !oif) || (addr_type & IPV6_ADDR_MAPPED) ||
(oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if))
(oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if &&!(mdev && sk->sk_bound_dev_if && bdev && mdev == bdev))) return -EINVAL; ipcm6_init_sk(&ipc6, np);However, this works by the test (888 passed) but your two liner is obviously better :-)
:)
Best regards, Mirsad
-- Mirsad Goran Todorovac Sistem inženjer Grafički fakultet | Akademija likovnih umjetnosti Sveučilište u Zagrebu
System engineer Faculty of Graphic Arts | Academy of Fine Arts University of Zagreb, Republic of Croatia