From 41a59c6f1ff6d49af2695ee52e65c91089a5a828 Mon Sep 17 00:00:00 2001 From: Xiyu Yang Date: Thu, 9 Sep 2021 12:32:00 +0800 Subject: [PATCH] net/l2tp: Fix reference count leak in l2tp_udp_recv_core commit 9b6ff7eb666415e1558f1ba8a742f5db6a9954de upstream. The reference count leak issue may take place in an error handling path. If both conditions of tunnel->version == L2TP_HDR_VER_3 and the return value of l2tp_v3_ensure_opt_in_linear is nonzero, the function would directly jump to label invalid, without decrementing the reference count of the l2tp_session object session increased earlier by l2tp_tunnel_get_session(). This may result in refcount leaks. Fix this issue by decrease the reference count before jumping to the label invalid. Fixes: 4522a70db7aa ("l2tp: fix reading optional fields of L2TPv3") Signed-off-by: Xiyu Yang Signed-off-by: Xin Xiong Signed-off-by: Xin Tan Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/l2tp/l2tp_core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index 15f8bd0364c2..f55ba8146254 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -994,8 +994,10 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, } if (tunnel->version == L2TP_HDR_VER_3 && - l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) + l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) { + l2tp_session_dec_refcount(session); goto error; + } l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook); l2tp_session_dec_refcount(session);