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Commit e372ecd4 authored by Congyu Liu's avatar Congyu Liu Committed by Greg Kroah-Hartman
Browse files

net: fix information leakage in /proc/net/ptype 



commit 47934e06b65637c88a762d9c98329ae6e3238888 upstream.

In one net namespace, after creating a packet socket without binding
it to a device, users in other net namespaces can observe the new
`packet_type` added by this packet socket by reading `/proc/net/ptype`
file. This is minor information leakage as packet socket is
namespace aware.

Add a net pointer in `packet_type` to keep the net namespace of
of corresponding packet socket. In `ptype_seq_show`, this net pointer
must be checked when it is not NULL.

Fixes: 2feb27db ("[NETNS]: Minor information leak via /proc/net/ptype file.")
Signed-off-by: default avatarCongyu Liu <liu3101@purdue.edu>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 20b7af41

include/linux/netdevice.h

+1 −0
Original line number Diff line number Diff line
@@ -2397,6 +2397,7 @@ struct packet_type { 
					      struct net_device *);

	bool			(*id_match)(struct packet_type *ptype,

					    struct sock *sk);

	struct net		*af_packet_net;

	void			*af_packet_priv;

	struct list_head	list;

};

net/core/net-procfs.c

+2 −1
Original line number Diff line number Diff line
@@ -252,7 +252,8 @@ static int ptype_seq_show(struct seq_file *seq, void *v) 


	if (v == SEQ_START_TOKEN)

		seq_puts(seq, "Type Device      Function\n");

	else if (pt->dev == NULL || dev_net(pt->dev) == seq_file_net(seq)) {

	else if ((!pt->af_packet_net || net_eq(pt->af_packet_net, seq_file_net(seq))) &&

		 (!pt->dev || net_eq(dev_net(pt->dev), seq_file_net(seq)))) {

		if (pt->type == htons(ETH_P_ALL))

			seq_puts(seq, "ALL ");

		else

net/packet/af_packet.c

+2 −0
Original line number Diff line number Diff line
@@ -1715,6 +1715,7 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags) 
		match->prot_hook.dev = po->prot_hook.dev;

		match->prot_hook.func = packet_rcv_fanout;

		match->prot_hook.af_packet_priv = match;

		match->prot_hook.af_packet_net = read_pnet(&match->net);

		match->prot_hook.id_match = match_fanout_group;

		list_add(&match->list, &fanout_list);

	}
@@ -3294,6 +3295,7 @@ static int packet_create(struct net *net, struct socket *sock, int protocol, 
		po->prot_hook.func = packet_rcv_spkt;



	po->prot_hook.af_packet_priv = sk;

	po->prot_hook.af_packet_net = sock_net(sk);



	if (proto) {

		po->prot_hook.type = proto;