linux-stable.git/net/ipv4/ip_output.c, branch linux-5.4.y

net: ipv4: fix a memleak in ip_setup_cork

2024-02-23T07:25:05+00:00

[ Upstream commit 5dee6d6923458e26966717f2a3eae7d09fc10bf6 ]

When inetdev_valid_mtu fails, cork->opt should be freed if it is
allocated in ip_setup_cork. Otherwise there could be a memleak.

Fixes: 501a90c94510 ("inet: protect against too small mtu values.")
Signed-off-by: Zhipeng Lu 
Reviewed-by: Eric Dumazet 
Link: https://lore.kernel.org/r/20240129091017.2938835-1-alexious@zju.edu.cn
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net-timestamp: extend SOF_TIMESTAMPING_OPT_ID to HW timestamps

2024-01-15T17:25:26+00:00

[ Upstream commit 8ca5a5790b9a1ce147484d2a2c4e66d2553f3d6c ]

When the feature was added it was enabled for SW timestamps only but
with current hardware the same out-of-order timestamps can be seen.
Let's expand the area for the feature to all types of timestamps.

Signed-off-by: Vadim Fedorenko 
Reviewed-by: Willem de Bruijn 
Signed-off-by: David S. Miller 
Stable-dep-of: 7f6ca95d16b9 ("net: Implement missing getsockopt(SO_TIMESTAMPING_NEW)")
Signed-off-by: Sasha Levin

lwt: Check LWTUNNEL_XMIT_CONTINUE strictly

2023-09-23T08:59:42+00:00

[ Upstream commit a171fbec88a2c730b108c7147ac5e7b2f5a02b47 ]

LWTUNNEL_XMIT_CONTINUE is implicitly assumed in ip(6)_finish_output2,
such that any positive return value from a xmit hook could cause
unexpected continue behavior, despite that related skb may have been
freed. This could be error-prone for future xmit hook ops. One of the
possible errors is to return statuses of dst_output directly.

To make the code safer, redefine LWTUNNEL_XMIT_CONTINUE value to
distinguish from dst_output statuses and check the continue
condition explicitly.

Fixes: 3a0af8fd61f9 ("bpf: BPF for lightweight tunnel infrastructure")
Suggested-by: Dan Carpenter 
Signed-off-by: Yan Zhai 
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/96b939b85eda00e8df4f7c080f770970a4c5f698.1692326837.git.yan@cloudflare.com
Signed-off-by: Sasha Levin

ipv4: Fix potential uninit variable access bug in __ip_make_skb()

2023-05-17T09:35:45+00:00

[ Upstream commit 99e5acae193e369b71217efe6f1dad42f3f18815 ]

Like commit ea30388baebc ("ipv6: Fix an uninit variable access bug in
__ip6_make_skb()"). icmphdr does not in skb linear region under the
scenario of SOCK_RAW socket. Access icmp_hdr(skb)->type directly will
trigger the uninit variable access bug.

Use a local variable icmp_type to carry the correct value in different
scenarios.

Fixes: 96793b482540 ("[IPV4]: Add ICMPMsgStats MIB (RFC 4293)")
Reviewed-by: Willem de Bruijn 
Signed-off-by: Ziyang Xuan 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

ipv4: tcp: send zero IPID in SYNACK messages

2022-02-01T16:24:39+00:00

[ Upstream commit 970a5a3ea86da637471d3cd04d513a0755aba4bf ]

In commit 431280eebed9 ("ipv4: tcp: send zero IPID for RST and
ACK sent in SYN-RECV and TIME-WAIT state") we took care of some
ctl packets sent by TCP.

It turns out we need to use a similar strategy for SYNACK packets.

By default, they carry IP_DF and IPID==0, but there are ways
to ask them to use the hashed IP ident generator and thus
be used to build off-path attacks.
(Ref: Off-Path TCP Exploits of the Mixed IPID Assignment)

One of this way is to force (before listener is started)
echo 1 >/proc/sys/net/ipv4/ip_no_pmtu_disc

Another way is using forged ICMP ICMP_FRAG_NEEDED
with a very small MTU (like 68) to force a false return from
ip_dont_fragment()

In this patch, ip_build_and_send_pkt() uses the following
heuristics.

1) Most SYNACK packets are smaller than IPV4_MIN_MTU and therefore
can use IP_DF regardless of the listener or route pmtu setting.

2) In case the SYNACK packet is bigger than IPV4_MIN_MTU,
we use prandom_u32() generator instead of the IPv4 hashed ident one.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet 
Reported-by: Ray Che 
Reviewed-by: David Ahern 
Cc: Geoff Alexander 
Cc: Willy Tarreau 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

ipv4: ip_output.c: Fix out-of-bounds warning in ip_copy_addrs()

2021-09-22T10:26:29+00:00

[ Upstream commit 6321c7acb82872ef6576c520b0e178eaad3a25c0 ]

Fix the following out-of-bounds warning:

    In function 'ip_copy_addrs',
        inlined from '__ip_queue_xmit' at net/ipv4/ip_output.c:517:2:
net/ipv4/ip_output.c:449:2: warning: 'memcpy' offset [40, 43] from the object at 'fl' is out of the bounds of referenced subobject 'saddr' with type 'unsigned int' at offset 36 [-Warray-bounds]
      449 |  memcpy(&iph->saddr, &fl4->saddr,
          |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      450 |         sizeof(fl4->saddr) + sizeof(fl4->daddr));
          |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The problem is that the original code is trying to copy data into a
couple of struct members adjacent to each other in a single call to
memcpy(). This causes a legitimate compiler warning because memcpy()
overruns the length of &iph->saddr and &fl4->saddr. As these are just
a couple of struct members, fix this by using direct assignments,
instead of memcpy().

This helps with the ongoing efforts to globally enable -Warray-bounds
and get us closer to being able to tighten the FORTIFY_SOURCE routines
on memcpy().

Link: https://github.com/KSPP/linux/issues/109
Reported-by: kernel test robot 
Link: https://lore.kernel.org/lkml/d5ae2e65-1f18-2577-246f-bada7eee6ccd@intel.com/
Signed-off-by: Gustavo A. R. Silva 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

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

2021-07-19T06:53:13+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

net: ip: always refragment ip defragmented packets

2021-01-17T13:05:32+00:00

[ Upstream commit bb4cc1a18856a73f0ff5137df0c2a31f4c50f6cf ]

Conntrack reassembly records the largest fragment size seen in IPCB.
However, when this gets forwarded/transmitted, fragmentation will only
be forced if one of the fragmented packets had the DF bit set.

In that case, a flag in IPCB will force fragmentation even if the
MTU is large enough.

This should work fine, but this breaks with ip tunnels.
Consider client that sends a UDP datagram of size X to another host.

The client fragments the datagram, so two packets, of size y and z, are
sent. DF bit is not set on any of these packets.

Middlebox netfilter reassembles those packets back to single size-X
packet, before routing decision.

packet-size-vs-mtu checks in ip_forward are irrelevant, because DF bit
isn't set.  At output time, ip refragmentation is skipped as well
because x is still smaller than the mtu of the output device.

If ttransmit device is an ip tunnel, the packet size increases to
x+overhead.

Also, tunnel might be configured to force DF bit on outer header.

In this case, packet will be dropped (exceeds MTU) and an ICMP error is
generated back to sender.

But sender already respects the announced MTU, all the packets that
it sent did fit the announced mtu.

Force refragmentation as per original sizes unconditionally so ip tunnel
will encapsulate the fragments instead.

The only other solution I see is to place ip refragmentation in
the ip_tunnel code to handle this case.

Fixes: d6b915e29f4ad ("ip_fragment: don't forward defragmented DF packet")
Reported-by: Christian Perle 
Signed-off-by: Florian Westphal 
Acked-by: Pablo Neira Ayuso 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

ip: fix tos reflection in ack and reset packets

2020-09-26T16:03:12+00:00

[ Upstream commit ba9e04a7ddf4f22a10e05bf9403db6b97743c7bf ]

Currently, in tcp_v4_reqsk_send_ack() and tcp_v4_send_reset(), we
echo the TOS value of the received packets in the response.
However, we do not want to echo the lower 2 ECN bits in accordance
with RFC 3168 6.1.5 robustness principles.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")

Signed-off-by: Wei Wang 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ip: Fix SO_MARK in RST, ACK and ICMP packets

2020-07-22T07:32:50+00:00

[ Upstream commit 0da7536fb47f51df89ccfcb1fa09f249d9accec5 ]

When no full socket is available, skbs are sent over a per-netns
control socket. Its sk_mark is temporarily adjusted to match that
of the real (request or timewait) socket or to reflect an incoming
skb, so that the outgoing skb inherits this in __ip_make_skb.

Introduction of the socket cookie mark field broke this. Now the
skb is set through the cookie and cork:

		# init sockc.mark from sk_mark or cmsg
ip_append_data
  ip_setup_cork		# convert sockc.mark to cork mark
ip_push_pending_frames
  ip_finish_skb
    __ip_make_skb	# set skb->mark to cork mark

But I missed these special control sockets. Update all callers of
__ip(6)_make_skb that were originally missed.

For IPv6, the same two icmp(v6) paths are affected. The third
case is not, as commit 92e55f412cff ("tcp: don't annotate
mark on control socket from tcp_v6_send_response()") replaced
the ctl_sk->sk_mark with passing the mark field directly as a
function argument. That commit predates the commit that
introduced the bug.

Fixes: c6af0c227a22 ("ip: support SO_MARK cmsg")
Signed-off-by: Willem de Bruijn 
Reported-by: Martin KaFai Lau 
Reviewed-by: Martin KaFai Lau 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman