linux-stable.git/net/ipv4, branch v4.19.36

net: ip_gre: fix possible use-after-free in erspan_rcv

2019-04-17T06:38:43+00:00

[ Upstream commit 492b67e28ee5f2a2522fb72e3d3bcb990e461514 ]

erspan tunnels run __iptunnel_pull_header on received skbs to remove
gre and erspan headers. This can determine a possible use-after-free
accessing pkt_md pointer in erspan_rcv since the packet will be 'uncloned'
running pskb_expand_head if it is a cloned gso skb (e.g if the packet has
been sent though a veth device). Fix it resetting pkt_md pointer after
__iptunnel_pull_header

Fixes: 1d7e2ed22f8d ("net: erspan: refactor existing erspan code")
Signed-off-by: Lorenzo Bianconi 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

vrf: check accept_source_route on the original netdevice

2019-04-17T06:38:42+00:00

[ Upstream commit 8c83f2df9c6578ea4c5b940d8238ad8a41b87e9e ]

Configuration check to accept source route IP options should be made on
the incoming netdevice when the skb->dev is an l3mdev master. The route
lookup for the source route next hop also needs the incoming netdev.

v2->v3:
- Simplify by passing the original netdevice down the stack (per David
  Ahern).

Signed-off-by: Stephen Suryaputra 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

tcp: fix a potential NULL pointer dereference in tcp_sk_exit

2019-04-17T06:38:41+00:00

[ Upstream commit b506bc975f60f06e13e74adb35e708a23dc4e87c ]

 When tcp_sk_init() failed in inet_ctl_sock_create(),
 'net->ipv4.tcp_congestion_control' will be left
 uninitialized, but tcp_sk_exit() hasn't check for
 that.

 This patch add checking on 'net->ipv4.tcp_congestion_control'
 in tcp_sk_exit() to prevent NULL-ptr dereference.

Fixes: 6670e1524477 ("tcp: Namespace-ify sysctl_tcp_default_congestion_control")
Signed-off-by: Dust Li 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

tcp: Ensure DCTCP reacts to losses

2019-04-17T06:38:41+00:00

[ Upstream commit aecfde23108b8e637d9f5c5e523b24fb97035dc3 ]

RFC8257 §3.5 explicitly states that "A DCTCP sender MUST react to
loss episodes in the same way as conventional TCP".

Currently, Linux DCTCP performs no cwnd reduction when losses
are encountered. Optionally, the dctcp_clamp_alpha_on_loss resets
alpha to its maximal value if a RTO happens. This behavior
is sub-optimal for at least two reasons: i) it ignores losses
triggering fast retransmissions; and ii) it causes unnecessary large
cwnd reduction in the future if the loss was isolated as it resets
the historical term of DCTCP's alpha EWMA to its maximal value (i.e.,
denoting a total congestion). The second reason has an especially
noticeable effect when using DCTCP in high BDP environments, where
alpha normally stays at low values.

This patch replace the clamping of alpha by setting ssthresh to
half of cwnd for both fast retransmissions and RTOs, at most once
per RTT. Consequently, the dctcp_clamp_alpha_on_loss module parameter
has been removed.

The table below shows experimental results where we measured the
drop probability of a PIE AQM (not applying ECN marks) at a
bottleneck in the presence of a single TCP flow with either the
alpha-clamping option enabled or the cwnd halving proposed by this
patch. Results using reno or cubic are given for comparison.

                          |  Link   |   RTT    |    Drop
                 TCP CC   |  speed  | base+AQM | probability
        ==================|=========|==========|============
                    CUBIC |  40Mbps |  7+20ms  |    0.21%
                     RENO |         |          |    0.19%
        DCTCP-CLAMP-ALPHA |         |          |   25.80%
         DCTCP-HALVE-CWND |         |          |    0.22%
        ------------------|---------|----------|------------
                    CUBIC | 100Mbps |  7+20ms  |    0.03%
                     RENO |         |          |    0.02%
        DCTCP-CLAMP-ALPHA |         |          |   23.30%
         DCTCP-HALVE-CWND |         |          |    0.04%
        ------------------|---------|----------|------------
                    CUBIC | 800Mbps |   1+1ms  |    0.04%
                     RENO |         |          |    0.05%
        DCTCP-CLAMP-ALPHA |         |          |   18.70%
         DCTCP-HALVE-CWND |         |          |    0.06%

We see that, without halving its cwnd for all source of losses,
DCTCP drives the AQM to large drop probabilities in order to keep
the queue length under control (i.e., it repeatedly faces RTOs).
Instead, if DCTCP reacts to all source of losses, it can then be
controlled by the AQM using similar drop levels than cubic or reno.

Signed-off-by: Koen De Schepper 
Signed-off-by: Olivier Tilmans 
Cc: Bob Briscoe 
Cc: Lawrence Brakmo 
Cc: Florian Westphal 
Cc: Daniel Borkmann 
Cc: Yuchung Cheng 
Cc: Neal Cardwell 
Cc: Eric Dumazet 
Cc: Andrew Shewmaker 
Cc: Glenn Judd 
Acked-by: Florian Westphal 
Acked-by: Neal Cardwell 
Acked-by: Daniel Borkmann 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

netfilter: ipt_CLUSTERIP: fix warning unused variable cn

2019-03-23T19:09:57+00:00

commit 206b8cc514d7ff2b79dd2d5ad939adc7c493f07a upstream.

When CONFIG_PROC_FS isn't set the variable cn isn't used.

net/ipv4/netfilter/ipt_CLUSTERIP.c: In function ‘clusterip_net_exit’:
net/ipv4/netfilter/ipt_CLUSTERIP.c:849:24: warning: unused variable ‘cn’ [-Wunused-variable]
  struct clusterip_net *cn = clusterip_pernet(net);
                        ^~

Rework so the variable 'cn' is declared inside "#ifdef CONFIG_PROC_FS".

Fixes: b12f7bad5ad3 ("netfilter: ipt_CLUSTERIP: remove wrong WARN_ON_ONCE in netns exit routine")
Signed-off-by: Anders Roxell 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman

esp: Skip TX bytes accounting when sending from a request socket

2019-03-23T19:09:48+00:00

[ Upstream commit 09db51241118aeb06e1c8cd393b45879ce099b36 ]

On ESP output, sk_wmem_alloc is incremented for the added padding if a
socket is associated to the skb. When replying with TCP SYNACKs over
IPsec, the associated sk is a casted request socket, only. Increasing
sk_wmem_alloc on a request socket results in a write at an arbitrary
struct offset. In the best case, this produces the following WARNING:

WARNING: CPU: 1 PID: 0 at lib/refcount.c:102 esp_output_head+0x2e4/0x308 [esp4]
refcount_t: addition on 0; use-after-free.
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.0.0-rc3 #2
Hardware name: Marvell Armada 380/385 (Device Tree)
[...]
[] (esp_output_head [esp4]) from [] (esp_output+0xb8/0x180 [esp4])
[] (esp_output [esp4]) from [] (xfrm_output_resume+0x558/0x664)
[] (xfrm_output_resume) from [] (xfrm4_output+0x44/0xc4)
[] (xfrm4_output) from [] (tcp_v4_send_synack+0xa8/0xe8)
[] (tcp_v4_send_synack) from [] (tcp_conn_request+0x7f4/0x948)
[] (tcp_conn_request) from [] (tcp_rcv_state_process+0x2a0/0xe64)
[] (tcp_rcv_state_process) from [] (tcp_v4_do_rcv+0xf0/0x1f4)
[] (tcp_v4_do_rcv) from [] (tcp_v4_rcv+0xdb8/0xe20)
[] (tcp_v4_rcv) from [] (ip_protocol_deliver_rcu+0x2c/0x2dc)
[] (ip_protocol_deliver_rcu) from [] (ip_local_deliver_finish+0x48/0x54)
[] (ip_local_deliver_finish) from [] (ip_local_deliver+0x54/0xec)
[] (ip_local_deliver) from [] (ip_rcv+0x48/0xb8)
[] (ip_rcv) from [] (__netif_receive_skb_one_core+0x50/0x6c)
[...]

The issue triggers only when not using TCP syncookies, as for syncookies
no socket is associated.

Fixes: cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible")
Fixes: 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible")
Signed-off-by: Martin Willi 
Signed-off-by: Steffen Klassert 
Signed-off-by: Sasha Levin

tcp: handle inet_csk_reqsk_queue_add() failures

2019-03-19T12:12:39+00:00

[  Upstream commit 9d3e1368bb45893a75a5dfb7cd21fdebfa6b47af ]

Commit 7716682cc58e ("tcp/dccp: fix another race at listener
dismantle") let inet_csk_reqsk_queue_add() fail, and adjusted
{tcp,dccp}_check_req() accordingly. However, TFO and syncookies
weren't modified, thus leaking allocated resources on error.

Contrary to tcp_check_req(), in both syncookies and TFO cases,
we need to drop the request socket. Also, since the child socket is
created with inet_csk_clone_lock(), we have to unlock it and drop an
extra reference (->sk_refcount is initially set to 2 and
inet_csk_reqsk_queue_add() drops only one ref).

For TFO, we also need to revert the work done by tcp_try_fastopen()
(with reqsk_fastopen_remove()).

Fixes: 7716682cc58e ("tcp/dccp: fix another race at listener dismantle")
Signed-off-by: Guillaume Nault 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: Don't access TCP_SKB_CB before initializing it

2019-03-19T12:12:39+00:00

[ Upstream commit f2feaefdabb0a6253aa020f65e7388f07a9ed47c ]

Since commit eeea10b83a13 ("tcp: add
tcp_v4_fill_cb()/tcp_v4_restore_cb()"), tcp_vX_fill_cb is only called
after tcp_filter(). That means, TCP_SKB_CB(skb)->end_seq still points to
the IP-part of the cb.

We thus should not mock with it, as this can trigger bugs (thanks
syzkaller):
[   12.349396] ==================================================================
[   12.350188] BUG: KASAN: slab-out-of-bounds in ip6_datagram_recv_specific_ctl+0x19b3/0x1a20
[   12.351035] Read of size 1 at addr ffff88006adbc208 by task test_ip6_datagr/1799

Setting end_seq is actually no more necessary in tcp_filter as it gets
initialized later on in tcp_vX_fill_cb.

Cc: Eric Dumazet 
Fixes: eeea10b83a13 ("tcp: add tcp_v4_fill_cb()/tcp_v4_restore_cb()")
Signed-off-by: Christoph Paasch 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: do not report TCP_CM_INQ of 0 for closed connections

2019-03-19T12:12:39+00:00

[ Upstream commit 6466e715651f9f358e60c5ea4880e4731325827f ]

Returning 0 as inq to userspace indicates there is no more data to
read, and the application needs to wait for EPOLLIN. For a connection
that has received FIN from the remote peer, however, the application
must continue reading until getting EOF (return value of 0
from tcp_recvmsg) or an error, if edge-triggered epoll (EPOLLET) is
being used. Otherwise, the application will never receive a new
EPOLLIN, since there is no epoll edge after the FIN.

Return 1 when there is no data left on the queue but the
connection has received FIN, so that the applications continue
reading.

Fixes: b75eba76d3d72 (tcp: send in-queue bytes in cmsg upon read)
Signed-off-by: Soheil Hassas Yeganeh 
Acked-by: Neal Cardwell 
Signed-off-by: Eric Dumazet 
Acked-by: Yuchung Cheng 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

route: set the deleted fnhe fnhe_daddr to 0 in ip_del_fnhe to fix a race

2019-03-19T12:12:39+00:00

[ Upstream commit ee60ad219f5c7c4fb2f047f88037770063ef785f ]

The race occurs in __mkroute_output() when 2 threads lookup a dst:

  CPU A                 CPU B
  find_exception()
                        find_exception() [fnhe expires]
                        ip_del_fnhe() [fnhe is deleted]
  rt_bind_exception()

In rt_bind_exception() it will bind a deleted fnhe with the new dst, and
this dst will get no chance to be freed. It causes a dev defcnt leak and
consecutive dmesg warnings:

  unregister_netdevice: waiting for ethX to become free. Usage count = 1

Especially thanks Jon to identify the issue.

This patch fixes it by setting fnhe_daddr to 0 in ip_del_fnhe() to stop
binding the deleted fnhe with a new dst when checking fnhe's fnhe_daddr
and daddr in rt_bind_exception().

It works as both ip_del_fnhe() and rt_bind_exception() are protected by
fnhe_lock and the fhne is freed by kfree_rcu().

Fixes: deed49df7390 ("route: check and remove route cache when we get route")
Signed-off-by: Jon Maxwell 
Signed-off-by: Xin Long 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman