Commit 4e4b21da authored by Guillaume Nault's avatar Guillaume Nault Committed by David S. Miller
Browse files

l2tp: hold tunnel while handling genl TUNNEL_GET commands 



Use l2tp_tunnel_get() instead of l2tp_tunnel_find() so that we get
a reference on the tunnel, preventing l2tp_tunnel_destruct() from
freeing it from under us.

Also move l2tp_tunnel_get() below nlmsg_new() so that we only take
the reference when needed.

Fixes: 309795f4 ("l2tp: Add netlink control API for L2TP")
Signed-off-by: default avatarGuillaume Nault <g.nault@alphalink.fr>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8c0e4215

net/l2tp/l2tp_netlink.c

+15 −12
Original line number Original line Diff line number Diff line
@@ -444,34 +444,37 @@ static int l2tp_nl_cmd_tunnel_get(struct sk_buff *skb, struct genl_info *info) 




	if (!info->attrs[L2TP_ATTR_CONN_ID]) {

	if (!info->attrs[L2TP_ATTR_CONN_ID]) {

		ret = -EINVAL;

		ret = -EINVAL;

		goto out;

		goto err;

	}

	}





	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);

	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);





	tunnel = l2tp_tunnel_find(net, tunnel_id);

	if (tunnel == NULL) {

		ret = -ENODEV;

		goto out;

	}



	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);

	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);

	if (!msg) {

	if (!msg) {

		ret = -ENOMEM;

		ret = -ENOMEM;

		goto out;

		goto err;

	}



	tunnel = l2tp_tunnel_get(net, tunnel_id);

	if (!tunnel) {

		ret = -ENODEV;

		goto err_nlmsg;

	}

	}





	ret = l2tp_nl_tunnel_send(msg, info->snd_portid, info->snd_seq,

	ret = l2tp_nl_tunnel_send(msg, info->snd_portid, info->snd_seq,

				  NLM_F_ACK, tunnel, L2TP_CMD_TUNNEL_GET);

				  NLM_F_ACK, tunnel, L2TP_CMD_TUNNEL_GET);

	if (ret < 0)

	if (ret < 0)

		goto err_out;

		goto err_nlmsg_tunnel;



	l2tp_tunnel_dec_refcount(tunnel);





	return genlmsg_unicast(net, msg, info->snd_portid);

	return genlmsg_unicast(net, msg, info->snd_portid);





err_out:

err_nlmsg_tunnel:

	l2tp_tunnel_dec_refcount(tunnel);

err_nlmsg:

	nlmsg_free(msg);

	nlmsg_free(msg);



err:

out:

	return ret;

	return ret;

}

}

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