Commit 9b6ff7eb authored by Xiyu Yang's avatar Xiyu Yang Committed by David S. Miller
Browse files

net/l2tp: Fix reference count leak in l2tp_udp_recv_core 



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: 4522a70d ("l2tp: fix reading optional fields of L2TPv3")
Signed-off-by: default avatarXiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: default avatarXin Xiong <xiongx18@fudan.edu.cn>
Signed-off-by: default avatarXin Tan <tanxin.ctf@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 04f08eb4

net/l2tp/l2tp_core.c

+3 −1
Original line number Diff line number Diff line
@@ -869,8 +869,10 @@ 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 invalid;

	}



	l2tp_recv_common(session, skb, ptr, optr, hdrflags, length);

	l2tp_session_dec_refcount(session);