linux-stable.git/net, branch v3.16.52

netfilter: xt_osf: Add missing permission checks

2018-01-01T20:52:09+00:00

commit 916a27901de01446bcf57ecca4783f6cff493309 upstream.

The capability check in nfnetlink_rcv() verifies that the caller
has CAP_NET_ADMIN in the namespace that "owns" the netlink socket.
However, xt_osf_fingers is shared by all net namespaces on the
system.  An unprivileged user can create user and net namespaces
in which he holds CAP_NET_ADMIN to bypass the netlink_net_capable()
check:

    vpnns -- nfnl_osf -f /tmp/pf.os

    vpnns -- nfnl_osf -f /tmp/pf.os -d

These non-root operations successfully modify the systemwide OS
fingerprint list.  Add new capable() checks so that they can't.

Signed-off-by: Kevin Cernekee 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Ben Hutchings

netlink: Add netns check on taps

2018-01-01T20:52:09+00:00

commit 93c647643b48f0131f02e45da3bd367d80443291 upstream.

Currently, a nlmon link inside a child namespace can observe systemwide
netlink activity.  Filter the traffic so that nlmon can only sniff
netlink messages from its own netns.

Test case:

    vpnns -- bash -c "ip link add nlmon0 type nlmon; \
                      ip link set nlmon0 up; \
                      tcpdump -i nlmon0 -q -w /tmp/nlmon.pcap -U" &
    sudo ip xfrm state add src 10.1.1.1 dst 10.1.1.2 proto esp \
        spi 0x1 mode transport \
        auth sha1 0x6162633132330000000000000000000000000000 \
        enc aes 0x00000000000000000000000000000000
    grep --binary abc123 /tmp/nlmon.pcap

Signed-off-by: Kevin Cernekee 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

netfilter: nfnetlink_cthelper: Add missing permission checks

2018-01-01T20:52:08+00:00

commit 4b380c42f7d00a395feede754f0bc2292eebe6e5 upstream.

The capability check in nfnetlink_rcv() verifies that the caller
has CAP_NET_ADMIN in the namespace that "owns" the netlink socket.
However, nfnl_cthelper_list is shared by all net namespaces on the
system.  An unprivileged user can create user and net namespaces
in which he holds CAP_NET_ADMIN to bypass the netlink_net_capable()
check:

    $ nfct helper list
    nfct v1.4.4: netlink error: Operation not permitted
    $ vpnns -- nfct helper list
    {
            .name = ftp,
            .queuenum = 0,
            .l3protonum = 2,
            .l4protonum = 6,
            .priv_data_len = 24,
            .status = enabled,
    };

Add capable() checks in nfnetlink_cthelper, as this is cleaner than
trying to generalize the solution.

Signed-off-by: Kevin Cernekee 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Ben Hutchings

Bluetooth: bnep: bnep_add_connection() should verify that it's dealing with l2cap socket

2018-01-01T20:52:08+00:00

commit 71bb99a02b32b4cc4265118e85f6035ca72923f0 upstream.

same story as cmtp

Signed-off-by: Al Viro 
Signed-off-by: Marcel Holtmann 
Signed-off-by: Ben Hutchings

Bluetooth: cmtp: cmtp_add_connection() should verify that it's dealing with l2cap socket

2018-01-01T20:52:08+00:00

commit 96c26653ce65bf84f3212f8b00d4316c1efcbf4c upstream.

... rather than relying on ciptool(8) never passing it anything else.  Give
it e.g. an AF_UNIX connected socket (from socketpair(2)) and it'll oops,
trying to evaluate &l2cap_pi(sock->sk)->chan->dst...

Signed-off-by: Al Viro 
Signed-off-by: Marcel Holtmann 
Signed-off-by: Ben Hutchings

dccp: CVE-2017-8824: use-after-free in DCCP code

2018-01-01T20:52:08+00:00

commit 69c64866ce072dea1d1e59a0d61e0f66c0dffb76 upstream.

Whenever the sock object is in DCCP_CLOSED state,
dccp_disconnect() must free dccps_hc_tx_ccid and
dccps_hc_rx_ccid and set to NULL.

Signed-off-by: Mohamed Ghannam 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

vlan: fix a use-after-free in vlan_device_event()

2018-01-01T20:52:07+00:00

commit 052d41c01b3a2e3371d66de569717353af489d63 upstream.

After refcnt reaches zero, vlan_vid_del() could free
dev->vlan_info via RCU:

	RCU_INIT_POINTER(dev->vlan_info, NULL);
	call_rcu(&vlan_info->rcu, vlan_info_rcu_free);

However, the pointer 'grp' still points to that memory
since it is set before vlan_vid_del():

        vlan_info = rtnl_dereference(dev->vlan_info);
        if (!vlan_info)
                goto out;
        grp = &vlan_info->grp;

Depends on when that RCU callback is scheduled, we could
trigger a use-after-free in vlan_group_for_each_dev()
right following this vlan_vid_del().

Fix it by moving vlan_vid_del() before setting grp. This
is also symmetric to the vlan_vid_add() we call in
vlan_device_event().

Reported-by: Fengguang Wu 
Fixes: efc73f4bbc23 ("net: Fix memory leak - vlan_info struct")
Cc: Alexander Duyck 
Cc: Linus Torvalds 
Cc: Girish Moodalbail 
Signed-off-by: Cong Wang 
Reviewed-by: Girish Moodalbail 
Tested-by: Fengguang Wu 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

l2tp: don't use l2tp_tunnel_find() in l2tp_ip and l2tp_ip6

2018-01-01T20:52:05+00:00

commit 8f7dc9ae4a7aece9fbc3e6637bdfa38b36bcdf09 upstream.

Using l2tp_tunnel_find() in l2tp_ip_recv() is wrong for two reasons:

  * It doesn't take a reference on the returned tunnel, which makes the
    call racy wrt. concurrent tunnel deletion.

  * The lookup is only based on the tunnel identifier, so it can return
    a tunnel that doesn't match the packet's addresses or protocol.

For example, a packet sent to an L2TPv3 over IPv6 tunnel can be
delivered to an L2TPv2 over UDPv4 tunnel. This is worse than a simple
cross-talk: when delivering the packet to an L2TP over UDP tunnel, the
corresponding socket is UDP, where ->sk_backlog_rcv() is NULL. Calling
sk_receive_skb() will then crash the kernel by trying to execute this
callback.

And l2tp_tunnel_find() isn't even needed here. __l2tp_ip_bind_lookup()
properly checks the socket binding and connection settings. It was used
as a fallback mechanism for finding tunnels that didn't have their data
path registered yet. But it's not limited to this case and can be used
to replace l2tp_tunnel_find() in the general case.

Fix l2tp_ip6 in the same way.

Fixes: 0d76751fad77 ("l2tp: Add L2TPv3 IP encapsulation (no UDP) support")
Fixes: a32e0eec7042 ("l2tp: introduce L2TPv3 IP encapsulation support for IPv6")
Signed-off-by: Guillaume Nault 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.16:
 - In l2tp_ip6.c, always look up in init_net
 - Adjust context]
Signed-off-by: Ben Hutchings

l2tp: hold tunnel socket when handling control frames in l2tp_ip and l2tp_ip6

2018-01-01T20:52:04+00:00

commit 94d7ee0baa8b764cf64ad91ed69464c1a6a0066b upstream.

The code following l2tp_tunnel_find() expects that a new reference is
held on sk. Either sk_receive_skb() or the discard_put error path will
drop a reference from the tunnel's socket.

This issue exists in both l2tp_ip and l2tp_ip6.

Fixes: a3c18422a4b4 ("l2tp: hold socket before dropping lock in l2tp_ip{, 6}_recv()")
Signed-off-by: Guillaume Nault 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

l2tp: hold socket before dropping lock in l2tp_ip{, 6}_recv()

2018-01-01T20:52:04+00:00

commit a3c18422a4b4e108bcf6a2328f48867e1003fd95 upstream.

Socket must be held while under the protection of the l2tp lock; there
is no guarantee that sk remains valid after the read_unlock_bh() call.

Same issue for l2tp_ip and l2tp_ip6.

Signed-off-by: Guillaume Nault 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings