Pablo Neira Ayuso says:

====================
Netfilter/IPVS fixes for net

The following patchset contains Netfilter/IPVS fixes for your net tree,
they are:

1) When using IPVS in direct-routing mode, normal traffic from the LVS
   host to a back-end server is sometimes incorrectly NATed on the way
   back into the LVS host. Patch to fix this from Julian Anastasov.

2) Calm down clang compilation warning in ctnetlink due to type
   mismatch, from Matthias Kaehlcke.

3) Do not re-setup NAT for conntracks that are already confirmed, this
   is fixing a problem that was introduced in the previous nf-next batch.
   Patch from Liping Zhang.

4) Do not allow conntrack helper removal from userspace cthelper
   infrastructure if already in used. This comes with an initial patch
   to introduce nf_conntrack_helper_put() that is required by this fix.
   From Liping Zhang.

5) Zero the pad when copying data to userspace, otherwise iptables fails
   to remove rules. This is a follow up on the patchset that sorts out
   the internal match/target structure pointer leak to userspace. Patch
   from the same author, Willem de Bruijn. This also comes with a build
   failure when CONFIG_COMPAT is not on, coming in the last patch of
   this series.

6) SYNPROXY crashes with conntrack entries that are created via
   ctnetlink, more specifically via conntrackd state sync. Patch from
   Eric Leblond.

7) RCU safe iteration on set element dumping in nf_tables, from
   Liping Zhang.

8) Missing sanitization of immediate date for the bitwise and cmp
   expressions in nf_tables.

9) Refcounting logic for chain and objects from set elements does not
   integrate into the nf_tables 2-phase commit protocol.

10) Missing sanitization of target verdict in ebtables arpreply target,
    from Gao Feng.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

The patch in the Fixes references COMPAT_XT_ALIGN in the definition
of XT_DATA_TO_USER, outside an #ifdef CONFIG_COMPAT block.

Split XT_DATA_TO_USER into separate compat and non compat variants and
define the first inside an CONFIG_COMPAT block.

This simplifies both variants by removing branches inside the macro.

Fixes: 324318f0248c ("netfilter: xtables: zero padding in data_to_user")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Andreas reports that the following incremental update using our commit
protocol doesn't work.

 # nft -f incremental-update.nft
 delete element ip filter client_to_any { 10.180.86.22 : goto CIn_1 }
 delete chain ip filter CIn_1
 ... Error: Could not process rule: Device or resource busy

The existing code is not well-integrated into the commit phase protocol,
since element deletions do not result in refcount decrement from the
preparation phase. This results in bogus EBUSY errors like the one
above.

Two new functions come with this patch:

* nft_set_elem_activate() function is used from the abort path, to
  restore the set element refcounting on objects that occurred from
  the preparation phase.

* nft_set_elem_deactivate() that is called from nft_del_setelem() to
  decrement set element refcounting on objects from the preparation
  phase in the commit protocol.

The nft_data_uninit() has been renamed to nft_data_release() since this
function does not uninitialize any data store in the data register,
instead just releases the references to objects. Moreover, a new
function nft_data_hold() has been introduced to be used from
nft_set_elem_activate().

Reported-by: Andreas Schultz <aschultz@tpip.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Do not assume userspace always sends us NFT_DATA_VALUE for bitwise and
cmp expressions. Although NFT_DATA_VERDICT does not make any sense, it
is still possible to handcraft a netlink message using this incorrect
data type.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

When dumping the elements related to a specified set, we may invoke the
nf_tables_dump_set with the NFNL_SUBSYS_NFTABLES lock not acquired. So
we should use the proper rcu operation to avoid race condition, just
like other nft dump operations.

Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

This patch fixes the creation of connection tracking entry from
netlink when synproxy is used. It was missing the addition of
the synproxy extension.

This was causing kernel crashes when a conntrack entry created by
conntrackd was used after the switch of traffic from active node
to the passive node.

Signed-off-by: Eric Leblond <eric@regit.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

When looking up an iptables rule, the iptables binary compares the
aligned match and target data (XT_ALIGN). In some cases this can
exceed the actual data size to include padding bytes.

Before commit f77bc5b23fb1 ("iptables: use match, target and data
copy_to_user helpers") the malloc()ed bytes were overwritten by the
kernel with kzalloced contents, zeroing the padding and making the
comparison succeed. After this patch, the kernel copies and clears
only data, leaving the padding bytes undefined.

Extend the clear operation from data size to aligned data size to
include the padding bytes, if any.

Padding bytes can be observed in both match and target, and the bug
triggered, by issuing a rule with match icmp and target ACCEPT:

  iptables -t mangle -A INPUT -i lo -p icmp --icmp-type 1 -j ACCEPT
  iptables -t mangle -D INPUT -i lo -p icmp --icmp-type 1 -j ACCEPT

Fixes: f77bc5b23fb1 ("iptables: use match, target and data copy_to_user helpers")
Reported-by: Paul Moore <pmoore@redhat.com>
Reported-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Simon Horman says:

====================
IPVS Fixes for v4.12

please consider this fix to IPVS for v4.12.

* It is a fix from Julian Anastasov to only SNAT SNAT packet replies only for
  NATed connections

My understanding is that this fix is appropriate for 4.9.25, 4.10.13, 4.11
as well as the nf tree. Julian has separately posted backports for other
-stable kernels; please see:

* [PATCH 3.2.88,3.4.113 -stable 1/3] ipvs: SNAT packet replies only for
        NATed connections
* [PATCH 3.10.105,3.12.73,3.16.43,4.1.39 -stable 2/3] ipvs: SNAT packet
        replies only for NATed connections
* [PATCH 4.4.65 -stable 3/3] ipvs: SNAT packet replies only for NATed
        connections
====================

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

We can still delete the ct helper even if it is in use, this will cause
a use-after-free error. In more detail, I mean:
  # nfct helper add ssdp inet udp
  # iptables -t raw -A OUTPUT -p udp -j CT --helper ssdp
  # nfct helper delete ssdp //--> oops, succeed!
  BUG: unable to handle kernel paging request at 000026ca
  IP: 0x26ca
  [...]
  Call Trace:
   ? ipv4_helper+0x62/0x80 [nf_conntrack_ipv4]
   nf_hook_slow+0x21/0xb0
   ip_output+0xe9/0x100
   ? ip_fragment.constprop.54+0xc0/0xc0
   ip_local_out+0x33/0x40
   ip_send_skb+0x16/0x80
   udp_send_skb+0x84/0x240
   udp_sendmsg+0x35d/0xa50

So add reference count to fix this issue, if ct helper is used by
others, reject the delete request.

Apply this patch:
  # nfct helper delete ssdp
  nfct v1.4.3: netlink error: Device or resource busy

Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

And convert module_put invocation to nf_conntrack_helper_put, this is
prepared for the followup patch, which will add a refcnt for cthelper,
so we can reject the deleting request when cthelper is in use.

Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>