linux-stable.git/net/ipv4, branch v5.2.15

tcp: remove empty skb from write queue in error cases

2019-09-10T09:35:06+00:00

[ Upstream commit fdfc5c8594c24c5df883583ebd286321a80e0a67 ]

Vladimir Rutsky reported stuck TCP sessions after memory pressure
events. Edge Trigger epoll() user would never receive an EPOLLOUT
notification allowing them to retry a sendmsg().

Jason tested the case of sk_stream_alloc_skb() returning NULL,
but there are other paths that could lead both sendmsg() and sendpage()
to return -1 (EAGAIN), with an empty skb queued on the write queue.

This patch makes sure we remove this empty skb so that
Jason code can detect that the queue is empty, and
call sk->sk_write_space(sk) accordingly.

Fixes: ce5ec440994b ("tcp: ensure epoll edge trigger wakeup when write queue is empty")
Signed-off-by: Eric Dumazet 
Cc: Jason Baron 
Reported-by: Vladimir Rutsky 
Cc: Soheil Hassas Yeganeh 
Cc: Neal Cardwell 
Acked-by: Soheil Hassas Yeganeh 
Acked-by: Neal Cardwell 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: inherit timestamp on mtu probe

2019-09-10T09:35:06+00:00

[ Upstream commit 888a5c53c0d8be6e98bc85b677f179f77a647873 ]

TCP associates tx timestamp requests with a byte in the bytestream.
If merging skbs in tcp_mtu_probe, migrate the tstamp request.

Similar to MSG_EOR, do not allow moving a timestamp from any segment
in the probe but the last. This to avoid merging multiple timestamps.

Tested with the packetdrill script at
https://github.com/wdebruij/packetdrill/commits/mtu_probe-1

Link: http://patchwork.ozlabs.org/patch/1143278/#2232897
Fixes: 4ed2d765dfac ("net-timestamp: TCP timestamping")
Signed-off-by: Willem de Bruijn 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv4/icmp: fix rt dst dev null pointer dereference

2019-09-06T08:23:33+00:00

[ Upstream commit e2c693934194fd3b4e795635934883354c06ebc9 ]

In __icmp_send() there is a possibility that the rt->dst.dev is NULL,
e,g, with tunnel collect_md mode, which will cause kernel crash.
Here is what the code path looks like, for GRE:

- ip6gre_tunnel_xmit
  - ip6gre_xmit_ipv4
    - __gre6_xmit
      - ip6_tnl_xmit
        - if skb->len - t->tun_hlen - eth_hlen > mtu; return -EMSGSIZE
    - icmp_send
      - net = dev_net(rt->dst.dev); <-- here

The reason is __metadata_dst_init() init dst->dev to NULL by default.
We could not fix it in __metadata_dst_init() as there is no dev supplied.
On the other hand, the reason we need rt->dst.dev is to get the net.
So we can just try get it from skb->dev when rt->dst.dev is NULL.

v4: Julian Anastasov remind skb->dev also could be NULL. We'd better
still use dst.dev and do a check to avoid crash.

v3: No changes.

v2: fix the issue in __icmp_send() instead of updating shared dst dev
in {ip_md, ip6}_tunnel_xmit.

Fixes: c8b34e680a09 ("ip_tunnel: Add tnl_update_pmtu in ip_md_tunnel_xmit")
Signed-off-by: Hangbin Liu 
Reviewed-by: Julian Anastasov 
Acked-by: Jonathan Lemon 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: fix __ip_mc_inc_group usage

2019-09-06T08:23:31+00:00

[ Upstream commit a1c4cd67840ef80f6ca5f73326fa9a6719303a95 ]

in ip_mc_inc_group, memory allocation flag, not mcast mode, is expected
by __ip_mc_inc_group

similar issue in __ip_mc_join_group, both mcase mode and gfp_t are needed
here, so use ____ip_mc_inc_group(...)

Fixes: 9fb20801dab4 ("net: Fix ip_mc_{dec,inc}_group allocation context")
Signed-off-by: Li RongQing 
Signed-off-by: Florian Fainelli 
Signed-off-by: Zhang Yu 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net/tls: prevent skb_orphan() from leaking TLS plain text with offload

2019-08-25T14:10:38+00:00

[ Upstream commit 414776621d1006e57e80e6db7fdc3837897aaa64 ]

sk_validate_xmit_skb() and drivers depend on the sk member of
struct sk_buff to identify segments requiring encryption.
Any operation which removes or does not preserve the original TLS
socket such as skb_orphan() or skb_clone() will cause clear text
leaks.

Make the TCP socket underlying an offloaded TLS connection
mark all skbs as decrypted, if TLS TX is in offload mode.
Then in sk_validate_xmit_skb() catch skbs which have no socket
(or a socket with no validation) and decrypted flag set.

Note that CONFIG_SOCK_VALIDATE_XMIT, CONFIG_TLS_DEVICE and
sk->sk_validate_xmit_skb are slightly interchangeable right now,
they all imply TLS offload. The new checks are guarded by
CONFIG_TLS_DEVICE because that's the option guarding the
sk_buff->decrypted member.

Second, smaller issue with orphaning is that it breaks
the guarantee that packets will be delivered to device
queues in-order. All TLS offload drivers depend on that
scheduling property. This means skb_orphan_partial()'s
trick of preserving partial socket references will cause
issues in the drivers. We need a full orphan, and as a
result netem delay/throttling will cause all TLS offload
skbs to be dropped.

Reusing the sk_buff->decrypted flag also protects from
leaking clear text when incoming, decrypted skb is redirected
(e.g. by TC).

See commit 0608c69c9a80 ("bpf: sk_msg, sock{map|hash} redirect
through ULP") for justification why the internal flag is safe.
The only location which could leak the flag in is tcp_bpf_sendmsg(),
which is taken care of by clearing the previously unused bit.

v2:
 - remove superfluous decrypted mark copy (Willem);
 - remove the stale doc entry (Boris);
 - rely entirely on EOR marking to prevent coalescing (Boris);
 - use an internal sendpages flag instead of marking the socket
   (Boris).
v3 (Willem):
 - reorganize the can_skb_orphan_partial() condition;
 - fix the flag leak-in through tcp_bpf_sendmsg.

Signed-off-by: Jakub Kicinski 
Acked-by: Willem de Bruijn 
Reviewed-by: Boris Pismenny 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

netfilter: Fix rpfilter dropping vrf packets by mistake

2019-08-16T08:10:59+00:00

[ Upstream commit b575b24b8eee37f10484e951b62ce2a31c579775 ]

When firewalld is enabled with ipv4/ipv6 rpfilter, vrf
ipv4/ipv6 packets will be dropped. Vrf device will pass
through netfilter hook twice. One with enslaved device
and another one with l3 master device. So in device may
dismatch witch out device because out device is always
enslaved device.So failed with the check of the rpfilter
and drop the packets by mistake.

Signed-off-by: Miaohe Lin 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

ipip: validate header length in ipip_tunnel_xmit

2019-08-09T15:51:43+00:00

[ Upstream commit 47d858d0bdcd47cc1c6c9eeca91b091dd9e55637 ]

We need the same checks introduced by commit cb9f1b783850
("ip: validate header length on virtual device xmit") for
ipip tunnel.

Fixes: cb9f1b783850b ("ip: validate header length on virtual device xmit")
Signed-off-by: Haishuang Yan 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: Reset bytes_acked and bytes_received when disconnecting

2019-07-28T06:27:17+00:00

[ Upstream commit e858faf556d4e14c750ba1e8852783c6f9520a0e ]

If an app is playing tricks to reuse a socket via tcp_disconnect(),
bytes_acked/received needs to be reset to 0. Otherwise tcp_info will
report the sum of the current and the old connection..

Cc: Eric Dumazet 
Fixes: 0df48c26d841 ("tcp: add tcpi_bytes_acked to tcp_info")
Fixes: bdd1f9edacb5 ("tcp: add tcpi_bytes_received to tcp_info")
Signed-off-by: Christoph Paasch 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: fix tcp_set_congestion_control() use from bpf hook

2019-07-28T06:27:16+00:00

[ Upstream commit 8d650cdedaabb33e85e9b7c517c0c71fcecc1de9 ]

Neal reported incorrect use of ns_capable() from bpf hook.

bpf_setsockopt(...TCP_CONGESTION...)
  -> tcp_set_congestion_control()
   -> ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)
    -> ns_capable_common()
     -> current_cred()
      -> rcu_dereference_protected(current->cred, 1)

Accessing 'current' in bpf context makes no sense, since packets
are processed from softirq context.

As Neal stated : The capability check in tcp_set_congestion_control()
was written assuming a system call context, and then was reused from
a BPF call site.

The fix is to add a new parameter to tcp_set_congestion_control(),
so that the ns_capable() call is only performed under the right
context.

Fixes: 91b5b21c7c16 ("bpf: Add support for changing congestion control")
Signed-off-by: Eric Dumazet 
Cc: Lawrence Brakmo 
Reported-by: Neal Cardwell 
Acked-by: Neal Cardwell 
Acked-by: Lawrence Brakmo 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: be more careful in tcp_fragment()

2019-07-28T06:27:16+00:00

[ Upstream commit b617158dc096709d8600c53b6052144d12b89fab ]

Some applications set tiny SO_SNDBUF values and expect
TCP to just work. Recent patches to address CVE-2019-11478
broke them in case of losses, since retransmits might
be prevented.

We should allow these flows to make progress.

This patch allows the first and last skb in retransmit queue
to be split even if memory limits are hit.

It also adds the some room due to the fact that tcp_sendmsg()
and tcp_sendpage() might overshoot sk_wmem_queued by about one full
TSO skb (64KB size). Note this allowance was already present
in stable backports for kernels < 4.15

Note for < 4.15 backports :
 tcp_rtx_queue_tail() will probably look like :

static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk)
{
	struct sk_buff *skb = tcp_send_head(sk);

	return skb ? tcp_write_queue_prev(sk, skb) : tcp_write_queue_tail(sk);
}

Fixes: f070ef2ac667 ("tcp: tcp_fragment() should apply sane memory limits")
Signed-off-by: Eric Dumazet 
Reported-by: Andrew Prout 
Tested-by: Andrew Prout 
Tested-by: Jonathan Lemon 
Tested-by: Michal Kubecek 
Acked-by: Neal Cardwell 
Acked-by: Yuchung Cheng 
Acked-by: Christoph Paasch 
Cc: Jonathan Looney 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman