This is a note to let you know that I've just added the patch titled
net: fix information leakage in /proc/net/ptype
to the 5.16-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-fix-information-leakage-in-proc-net-ptype.patch
and it can be found in the queue-5.16 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f5b386035483bc97628ddc430e17fda12326647c
Author: Congyu Liu <liu3101@xxxxxxxxxx>
Date: Tue Jan 18 14:20:13 2022 -0500
net: fix information leakage in /proc/net/ptype
[ Upstream commit 47934e06b65637c88a762d9c98329ae6e3238888 ]
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: 2feb27dbe00c ("[NETNS]: Minor information leak via /proc/net/ptype file.")
Signed-off-by: Congyu Liu <liu3101@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 6aadcc0ecb5b0..6cbefb660fa3b 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2636,6 +2636,7 @@ 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;
};
diff --git a/net/core/net-procfs.c b/net/core/net-procfs.c
index d8b9dbabd4a43..5b8016335acaf 100644
--- a/net/core/net-procfs.c
+++ b/net/core/net-procfs.c
@@ -260,7 +260,8 @@ 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
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 76c2dca7f0a59..43eef5c712c1e 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1773,6 +1773,7 @@ static int fanout_add(struct sock *sk, struct fanout_args *args)
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;
match->max_num_members = args->max_num_members;
list_add(&match->list, &fanout_list);
@@ -3358,6 +3359,7 @@ 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;
