When transferring from the original range in nf_nat_masquerade_{ipv4,ipv6}()
we copy over values from stack in from min_proto/max_proto due to uninitialized
range variable in both, nft_masq_{ipv4,ipv6}_eval. As we only initialize
flags at this time from nft_masq struct, just zero out the rest.

Fixes: 9ba1f726bec09 ("netfilter: nf_tables: add new nft_masq expression")
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

That can be reused by the reject bridge expression to build the reject
packet. The new functions are:

* nf_reject_ip6_tcphdr_get(): to sanitize and to obtain the TCP header.
* nf_reject_ip6hdr_put(): to build the IPv6 header.
* nf_reject_ip6_tcphdr_put(): to build the TCP header.

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

This adds the missing validation code to avoid the use of nat/masq from
non-nat chains. The validation assumes two possible configuration
scenarios:

1) Use of nat from base chain that is not of nat type. Reject this
   configuration from the nft_*_init() path of the expression.

2) Use of nat from non-base chain. In this case, we have to wait until
   the non-base chain is referenced by at least one base chain via
   jump/goto. This is resolved from the nft_*_validate() path which is
   called from nf_tables_check_loops().

The user gets an -EOPNOTSUPP in both cases.

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

[   23.545204] nf_reject_ipv4: module license 'unspecified' taints kernel.

Fixes: c8d7b98 ("netfilter: move nf_send_resetX() code to nf_reject_ipvX modules")
Reported-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

We have to register the notifiers in the masquerade expression from
the the module _init and _exit path.

This fixes crashes when removing the masquerade rule with no
ipt_MASQUERADE support in place (which was masking the problem).

Fixes: 9ba1f72 ("netfilter: nf_tables: add new nft_masq expression")
Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

In 34666d4 ("netfilter: bridge: move br_netfilter out of the core"),
the bridge netfilter code has been modularized.

Use IS_ENABLED instead of ifdef to cover the module case.

Fixes: 34666d4 ("netfilter: bridge: move br_netfilter out of the core")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Move nf_send_reset() and nf_send_reset6() to nf_reject_ipv4 and
nf_reject_ipv6 respectively. This code is shared by x_tables and
nf_tables.

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

Users are starting to test nf_tables with no x_tables support. Therefore,
masquerading needs to be indenpendent of it from Kconfig.

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

Now that we have masquerading support in nf_tables, the NAT chain can
be use with it, not only for SNAT/DNAT. So make this chain type
independent of it.

While at it, move it inside the scope of 'if NF_NAT_IPV*' to simplify
dependencies.

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

Pablo Neira Ayuso says:

====================
nf-next pull request

The following patchset contains Netfilter/IPVS updates for your
net-next tree. Regarding nf_tables, most updates focus on consolidating
the NAT infrastructure and adding support for masquerading. More
specifically, they are:

1) use __u8 instead of u_int8_t in arptables header, from
   Mike Frysinger.

2) Add support to match by skb->pkttype to the meta expression, from
   Ana Rey.

3) Add support to match by cpu to the meta expression, also from
   Ana Rey.

4) A smatch warning about IPSET_ATTR_MARKMASK validation, patch from
   Vytas Dauksa.

5) Fix netnet and netportnet hash types the range support for IPv4,
   from Sergey Popovich.

6) Fix missing-field-initializer warnings resolved, from Mark Rustad.

7) Dan Carperter reported possible integer overflows in ipset, from
   Jozsef Kadlecsick.

8) Filter out accounting objects in nfacct by type, so you can
   selectively reset quotas, from Alexey Perevalov.

9) Move specific NAT IPv4 functions to the core so x_tables and
   nf_tables can share the same NAT IPv4 engine.

10) Use the new NAT IPv4 functions from nft_chain_nat_ipv4.

11) Move specific NAT IPv6 functions to the core so x_tables and
    nf_tables can share the same NAT IPv4 engine.

12) Use the new NAT IPv6 functions from nft_chain_nat_ipv6.

13) Refactor code to add nft_delrule(), which can be reused in the
    enhancement of the NFT_MSG_DELTABLE to remove a table and its
    content, from Arturo Borrero.

14) Add a helper function to unregister chain hooks, from
    Arturo Borrero.

15) A cleanup to rename to nft_delrule_by_chain for consistency with
    the new nft_*() functions, also from Arturo.

16) Add support to match devgroup to the meta expression, from Ana Rey.

17) Reduce stack usage for IPVS socket option, from Julian Anastasov.

18) Remove unnecessary textsearch state initialization in xt_string,
    from Bojan Prtvar.

19) Add several helper functions to nf_tables, more work to prepare
    the enhancement of NFT_MSG_DELTABLE, again from Arturo Borrero.

20) Enhance NFT_MSG_DELTABLE to delete a table and its content, from
    Arturo Borrero.

21) Support NAT flags in the nat expression to indicate the flavour,
    eg. random fully, from Arturo.

22) Add missing audit code to ebtables when replacing tables, from
    Nicolas Dichtel.

23) Generalize the IPv4 masquerading code to allow its re-use from
    nf_tables, from Arturo.

24) Generalize the IPv6 masquerading code, also from Arturo.

25) Add the new masq expression to support IPv4/IPv6 masquerading
    from nf_tables, also from Arturo.
====================

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