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: 2feb27dbe0
("[NETNS]: Minor information leak via /proc/net/ptype file.")
Signed-off-by: Congyu Liu <liu3101@purdue.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:

committed by
Greg Kroah-Hartman

parent
feb770cc00
commit
db044d9746
@@ -1735,6 +1735,7 @@ static int fanout_add(struct sock *sk, struct fanout_args *args)
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match->prot_hook.dev = po->prot_hook.dev;
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match->prot_hook.func = packet_rcv_fanout;
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match->prot_hook.af_packet_priv = match;
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match->prot_hook.af_packet_net = read_pnet(&match->net);
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match->prot_hook.id_match = match_fanout_group;
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match->max_num_members = args->max_num_members;
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list_add(&match->list, &fanout_list);
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@@ -3323,6 +3324,7 @@ static int packet_create(struct net *net, struct socket *sock, int protocol,
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po->prot_hook.func = packet_rcv_spkt;
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po->prot_hook.af_packet_priv = sk;
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po->prot_hook.af_packet_net = sock_net(sk);
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if (proto) {
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po->prot_hook.type = proto;
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