linux-stable.git/net/ipv4, branch v5.13.4

net: ip: avoid OOM kills with large UDP sends over loopback

2021-07-19T08:04:44+00:00

[ Upstream commit 6d123b81ac615072a8525c13c6c41b695270a15d ]

Dave observed number of machines hitting OOM on the UDP send
path. The workload seems to be sending large UDP packets over
loopback. Since loopback has MTU of 64k kernel will try to
allocate an skb with up to 64k of head space. This has a good
chance of failing under memory pressure. What's worse if
the message length is <32k the allocation may trigger an
OOM killer.

This is entirely avoidable, we can use an skb with page frags.

af_unix solves a similar problem by limiting the head
length to SKB_MAX_ALLOC. This seems like a good and simple
approach. It means that UDP messages > 16kB will now
use fragments if underlying device supports SG, if extra
allocator pressure causes regressions in real workloads
we can switch to trying the large allocation first and
falling back.

v4: pre-calculate all the additions to alloclen so
    we can be sure it won't go over order-2

Reported-by: Dave Jones 
Signed-off-by: Jakub Kicinski 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

icmp: fix lib conflict with trinity

2021-07-19T08:04:36+00:00

[ Upstream commit e32ea44c7ae476f4c90e35ab0a29dc8ff082bc11 ]

Including  and  in the dependencies breaks
compilation of trinity due to multiple definitions.  is only
used in  to provide the definition of the struct in_addr,
but this can be substituted out by using the datatype __be32.

Signed-off-by: Andreas Roeseler 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

net: tcp better handling of reordering then loss cases

2021-07-19T08:04:35+00:00

[ Upstream commit a29cb6914681a55667436a9eb7a42e28da8cf387 ]

This patch aims to improve the situation when reordering and loss are
ocurring in the same flight of packets.

Previously the reordering would first induce a spurious recovery, then
the subsequent ACK may undo the cwnd (based on the timestamps e.g.).
However the current loss recovery does not proceed to invoke
RACK to install a reordering timer. If some packets are also lost, this
may lead to a long RTO-based recovery. An example is
https://groups.google.com/g/bbr-dev/c/OFHADvJbTEI

The solution is to after reverting the recovery, always invoke RACK
to either mount the RACK timer to fast retransmit after the reordering
window, or restarts the recovery if new loss is identified. Hence
it is possible the sender may go from Recovery to Disorder/Open to
Recovery again in one ACK.

Reported-by: mingkun bian 
Signed-off-by: Yuchung Cheng 
Signed-off-by: Neal Cardwell 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

net: lwtunnel: handle MTU calculation in forwading

2021-07-14T15:07:23+00:00

[ Upstream commit fade56410c22cacafb1be9f911a0afd3701d8366 ]

Commit 14972cbd34ff ("net: lwtunnel: Handle fragmentation") moved
fragmentation logic away from lwtunnel by carry encap headroom and
use it in output MTU calculation. But the forwarding part was not
covered and created difference in MTU for output and forwarding and
further to silent drops on ipv4 forwarding path. Fix it by taking
into account lwtunnel encap headroom.

The same commit also introduced difference in how to treat RTAX_MTU
in IPv4 and IPv6 where latter explicitly removes lwtunnel encap
headroom from route MTU. Make IPv4 version do the same.

Fixes: 14972cbd34ff ("net: lwtunnel: Handle fragmentation")
Suggested-by: David Ahern 
Signed-off-by: Vadim Fedorenko 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

net/ipv4: swap flow ports when validating source

2021-07-14T15:07:15+00:00

[ Upstream commit c69f114d09891adfa3e301a35d9e872b8b7b5a50 ]

When doing source address validation, the flowi4 struct used for
fib_lookup should be in the reverse direction to the given skb.
fl4_dport and fl4_sport returned by fib4_rules_early_flow_dissect
should thus be swapped.

Fixes: 5a847a6e1477 ("net/ipv4: Initialize proto and ports in flow struct")
Signed-off-by: Miao Wang 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

udp: Fix a memory leak in udp_read_sock()

2021-07-14T15:07:12+00:00

[ Upstream commit e00a5c331bf57f41fcfdc5da4f5caeafe5e54c1d ]

sk_psock_verdict_recv() clones the skb and uses the clone
afterward, so udp_read_sock() should free the skb after using
it, regardless of error or not.

This fixes a real kmemleak.

Fixes: d7f571188ecf ("udp: Implement ->read_sock() for sockmap")
Signed-off-by: Cong Wang 
Signed-off-by: Daniel Borkmann 
Acked-by: John Fastabend 
Acked-by: Jakub Sitnicki 
Link: https://lore.kernel.org/bpf/20210615021342.7416-4-xiyou.wangcong@gmail.com
Signed-off-by: Sasha Levin

rtnetlink: avoid RCU read lock when holding RTNL

2021-07-14T15:06:56+00:00

[ Upstream commit a100243d95a60d74ae9bb9df1f5f2192e9aed6a7 ]

When we call af_ops->set_link_af() we hold a RCU read lock
as we retrieve af_ops from the RCU protected list, but this
is unnecessary because we already hold RTNL lock, which is
the writer lock for protecting rtnl_af_ops, so it is safer
than RCU read lock. Similar for af_ops->validate_link_af().

This was not a problem until we begin to take mutex lock
down the path of ->set_link_af() in __ipv6_dev_mc_dec()
recently. We can just drop the RCU read lock there and
assert RTNL lock.

Reported-and-tested-by: syzbot+7d941e89dd48bcf42573@syzkaller.appspotmail.com
Fixes: 63ed8de4be81 ("mld: add mc_lock for protecting per-interface mld data")
Tested-by: Taehee Yoo 
Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

xfrm: xfrm_state_mtu should return at least 1280 for ipv6

2021-07-14T15:06:54+00:00

[ Upstream commit b515d2637276a3810d6595e10ab02c13bfd0b63a ]

Jianwen reported that IPv6 Interoperability tests are failing in an
IPsec case where one of the links between the IPsec peers has an MTU
of 1280. The peer generates a packet larger than this MTU, the router
replies with a "Packet too big" message indicating an MTU of 1280.
When the peer tries to send another large packet, xfrm_state_mtu
returns 1280 - ipsec_overhead, which causes ip6_setup_cork to fail
with EINVAL.

We can fix this by forcing xfrm_state_mtu to return IPV6_MIN_MTU when
IPv6 is used. After going through IPsec, the packet will then be
fragmented to obey the actual network's PMTU, just before leaving the
host.

Currently, TFC padding is capped to PMTU - overhead to avoid
fragementation: after padding and encapsulation, we still fit within
the PMTU. That behavior is preserved in this patch.

Fixes: 91657eafb64b ("xfrm: take net hdr len into account for esp payload size calculation")
Reported-by: Jianwen Ji 
Signed-off-by: Sabrina Dubroca 
Signed-off-by: Steffen Klassert 
Signed-off-by: Sasha Levin

icmp: don't send out ICMP messages with a source address of 0.0.0.0

2021-06-18T19:13:24+00:00

When constructing ICMP response messages, the kernel will try to pick a
suitable source address for the outgoing packet. However, if no IPv4
addresses are configured on the system at all, this will fail and we end up
producing an ICMP message with a source address of 0.0.0.0. This can happen
on a box routing IPv4 traffic via v6 nexthops, for instance.

Since 0.0.0.0 is not generally routable on the internet, there's a good
chance that such ICMP messages will never make it back to the sender of the
original packet that the ICMP message was sent in response to. This, in
turn, can create connectivity and PMTUd problems for senders. Fortunately,
RFC7600 reserves a dummy address to be used as a source for ICMP
messages (192.0.0.8/32), so let's teach the kernel to substitute that
address as a last resort if the regular source address selection procedure
fails.

Below is a quick example reproducing this issue with network namespaces:

ip netns add ns0
ip l add type veth peer netns ns0
ip l set dev veth0 up
ip a add 10.0.0.1/24 dev veth0
ip a add fc00:dead:cafe:42::1/64 dev veth0
ip r add 10.1.0.0/24 via inet6 fc00:dead:cafe:42::2
ip -n ns0 l set dev veth0 up
ip -n ns0 a add fc00:dead:cafe:42::2/64 dev veth0
ip -n ns0 r add 10.0.0.0/24 via inet6 fc00:dead:cafe:42::1
ip netns exec ns0 sysctl -w net.ipv4.icmp_ratelimit=0
ip netns exec ns0 sysctl -w net.ipv4.ip_forward=1
tcpdump -tpni veth0 -c 2 icmp &
ping -w 1 10.1.0.1 > /dev/null
tcpdump: verbose output suppressed, use -v[v]... for full protocol decode
listening on veth0, link-type EN10MB (Ethernet), snapshot length 262144 bytes
IP 10.0.0.1 > 10.1.0.1: ICMP echo request, id 29, seq 1, length 64
IP 0.0.0.0 > 10.0.0.1: ICMP net 10.1.0.1 unreachable, length 92
2 packets captured
2 packets received by filter
0 packets dropped by kernel

With this patch the above capture changes to:
IP 10.0.0.1 > 10.1.0.1: ICMP echo request, id 31127, seq 1, length 64
IP 192.0.0.8 > 10.0.0.1: ICMP net 10.1.0.1 unreachable, length 92

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Juliusz Chroboczek 
Reviewed-by: David Ahern 
Signed-off-by: Toke Høiland-Jørgensen 
Signed-off-by: David S. Miller

net: ipv4: fix memory leak in ip_mc_add1_src

2021-06-16T19:41:01+00:00

BUG: memory leak
unreferenced object 0xffff888101bc4c00 (size 32):
  comm "syz-executor527", pid 360, jiffies 4294807421 (age 19.329s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
    01 00 00 00 00 00 00 00 ac 14 14 bb 00 00 02 00 ................
  backtrace:
    [<00000000f17c5244>] kmalloc include/linux/slab.h:558 [inline]
    [<00000000f17c5244>] kzalloc include/linux/slab.h:688 [inline]
    [<00000000f17c5244>] ip_mc_add1_src net/ipv4/igmp.c:1971 [inline]
    [<00000000f17c5244>] ip_mc_add_src+0x95f/0xdb0 net/ipv4/igmp.c:2095
    [<000000001cb99709>] ip_mc_source+0x84c/0xea0 net/ipv4/igmp.c:2416
    [<0000000052cf19ed>] do_ip_setsockopt net/ipv4/ip_sockglue.c:1294 [inline]
    [<0000000052cf19ed>] ip_setsockopt+0x114b/0x30c0 net/ipv4/ip_sockglue.c:1423
    [<00000000477edfbc>] raw_setsockopt+0x13d/0x170 net/ipv4/raw.c:857
    [<00000000e75ca9bb>] __sys_setsockopt+0x158/0x270 net/socket.c:2117
    [<00000000bdb993a8>] __do_sys_setsockopt net/socket.c:2128 [inline]
    [<00000000bdb993a8>] __se_sys_setsockopt net/socket.c:2125 [inline]
    [<00000000bdb993a8>] __x64_sys_setsockopt+0xba/0x150 net/socket.c:2125
    [<000000006a1ffdbd>] do_syscall_64+0x40/0x80 arch/x86/entry/common.c:47
    [<00000000b11467c4>] entry_SYSCALL_64_after_hwframe+0x44/0xae

In commit 24803f38a5c0 ("igmp: do not remove igmp souce list info when set
link down"), the ip_mc_clear_src() in ip_mc_destroy_dev() was removed,
because it was also called in igmpv3_clear_delrec().

Rough callgraph:

inetdev_destroy
-> ip_mc_destroy_dev
     -> igmpv3_clear_delrec
        -> ip_mc_clear_src
-> RCU_INIT_POINTER(dev->ip_ptr, NULL)

However, ip_mc_clear_src() called in igmpv3_clear_delrec() doesn't
release in_dev->mc_list->sources. And RCU_INIT_POINTER() assigns the
NULL to dev->ip_ptr. As a result, in_dev cannot be obtained through
inetdev_by_index() and then in_dev->mc_list->sources cannot be released
by ip_mc_del1_src() in the sock_close. Rough call sequence goes like:

sock_close
-> __sock_release
   -> inet_release
      -> ip_mc_drop_socket
         -> inetdev_by_index
         -> ip_mc_leave_src
            -> ip_mc_del_src
               -> ip_mc_del1_src

So we still need to call ip_mc_clear_src() in ip_mc_destroy_dev() to free
in_dev->mc_list->sources.

Fixes: 24803f38a5c0 ("igmp: do not remove igmp souce list info ...")
Reported-by: Hulk Robot 
Signed-off-by: Chengyang Fan 
Acked-by: Hangbin Liu 
Signed-off-by: David S. Miller