4.10-stable review patch. If anyone has any objections, please let me know.
------------------ From: Guillaume Nault <[email protected]> [ Upstream commit 94d7ee0baa8b764cf64ad91ed69464c1a6a0066b ] The code following l2tp_tunnel_find() expects that a new reference is held on sk. Either sk_receive_skb() or the discard_put error path will drop a reference from the tunnel's socket. This issue exists in both l2tp_ip and l2tp_ip6. Fixes: a3c18422a4b4 ("l2tp: hold socket before dropping lock in l2tp_ip{, 6}_recv()") Signed-off-by: Guillaume Nault <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- net/l2tp/l2tp_ip.c | 5 +++-- net/l2tp/l2tp_ip6.c | 5 +++-- 2 files changed, 6 insertions(+), 4 deletions(-) --- a/net/l2tp/l2tp_ip.c +++ b/net/l2tp/l2tp_ip.c @@ -171,9 +171,10 @@ pass_up: tunnel_id = ntohl(*(__be32 *) &skb->data[4]); tunnel = l2tp_tunnel_find(net, tunnel_id); - if (tunnel != NULL) + if (tunnel) { sk = tunnel->sock; - else { + sock_hold(sk); + } else { struct iphdr *iph = (struct iphdr *) skb_network_header(skb); read_lock_bh(&l2tp_ip_lock); --- a/net/l2tp/l2tp_ip6.c +++ b/net/l2tp/l2tp_ip6.c @@ -183,9 +183,10 @@ pass_up: tunnel_id = ntohl(*(__be32 *) &skb->data[4]); tunnel = l2tp_tunnel_find(net, tunnel_id); - if (tunnel != NULL) + if (tunnel) { sk = tunnel->sock; - else { + sock_hold(sk); + } else { struct ipv6hdr *iph = ipv6_hdr(skb); read_lock_bh(&l2tp_ip6_lock);
