netfilter: nf_tables: use NLA_POLICY_MASK to test for valid flag options

nf_tables relies on manual test of netlink attributes coming from userspace
even in cases where this could be handled via netlink policy.

Convert a bunch of 'flag' attributes to use NLA_POLICY_MASK checks.

Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nft_masq: deduplicate eval call-backs

nft_masq has separate ipv4 and ipv6 call-backs which share much of their
code, and an inet one switch containing a switch that calls one of the
others based on the family of the packet. Merge the ipv4 and ipv6 ones
into the inet one in order to get rid of the duplicate code.

Const-qualify the `priv` pointer since we don't need to write through it.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Florian Westphal <fw@strlen.de>

netfilter: nft_masq: correct length for loading protocol registers

The values in the protocol registers are two bytes wide. However, when
parsing the register loads, the code currently uses the larger 16-byte
size of a `union nf_inet_addr`. Change it to use the (correct) size of
a `union nf_conntrack_man_proto` instead.

Fixes: 8a6bf5da1aef ("netfilter: nft_masq: support port range")
Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: Extend nft_expr_ops::dump callback parameters

Add a 'reset' flag just like with nft_object_ops::dump. This will be
useful to reset "anonymous stateful objects", e.g. simple rule counters.

No functional change intended.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: do not reduce read-only expressions

Skip register tracking for expressions that perform read-only operations
on the registers. Define and use a cookie pointer NFT_REDUCE_READONLY to
avoid defining stubs for these expressions.

This patch re-enables register tracking which was disabled in ed5f85d42290
("netfilter: nf_tables: disable register tracking"). Follow up patches
add remaining register tracking for existing expressions.

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

netfilter: nftables: add nft_parse_register_load() and use it

This new function combines the netlink register attribute parser
and the load validation function.

This update requires to replace:

enum nft_registers sreg:8;

in many of the expression private areas otherwise compiler complains
with:

error: cannot take address of bit-field ‘sreg’

when passing the register field as reference.

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

netfilter: Add MODULE_DESCRIPTION entries to kernel modules

The user tool modinfo is used to get information on kernel modules, including a
description where it is available.

This patch adds a brief MODULE_DESCRIPTION to netfilter kernel modules
(descriptions taken from Kconfig file or code comments)

Signed-off-by: Rob Gill <rrobgill@protonmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

treewide: Use sizeof_field() macro

Replace all the occurrences of FIELD_SIZEOF() with sizeof_field() except
at places where these are defined. Later patches will remove the unused
definition of FIELD_SIZEOF().

This patch is generated using following script:

EXCLUDE_FILES="include/linux/stddef.h|include/linux/kernel.h"

git grep -l -e "\bFIELD_SIZEOF\b" | while read file;
do

if [[ "$file" =~ $EXCLUDE_FILES ]]; then
continue
fi
sed -i -e 's/\bFIELD_SIZEOF\b/sizeof_field/g' $file;
done

Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>
Link: https://lore.kernel.org/r/20190924105839.110713-3-pankaj.laxminarayan.bharadiya@intel.com
Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: David Miller <davem@davemloft.net> # for net

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

netfilter: nf_tables: fix module autoload with inet family

Use MODULE_ALIAS_NFT_EXPR() to make happy the inet family with nat.

Fixes: 63ce3940f3ab ("netfilter: nft_redir: add inet support")
Fixes: 071657d2c38c ("netfilter: nft_masq: add inet support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_nat_masquerade: unify ipv4/6 notifier registration

Only reason for having two different register functions was because of
ipt_MASQUERADE and ip6t_MASQUERADE being two different modules.

Previous patch merged those into xt_MASQUERADE, so we can merge this too.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_nat: merge ip/ip6 masquerade headers

Both are now implemented by nf_nat_masquerade.c, so no need to keep
different headers.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nft_masq: add inet support

This allows use of a single masquerade rule in nat inet family
to handle both ipv4 and ipv6.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: nat: merge nft_masq protocol specific modules

The family specific masq modules are way too small to warrant
an extra module, just place all of them in nft_masq.

before:
text data bss dec hex filename
1001 832 0 1833 729 nft_masq.ko
766 896 0 1662 67e nft_masq_ipv4.ko
764 896 0 1660 67c nft_masq_ipv6.ko

after:
2010 960 0 2970 b9a nft_masq.ko

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_tables: add single table list for all families

Place all existing user defined tables in struct net *, instead of
having one list per family. This saves us from one level of indentation
in netlink dump functions.

Place pointer to struct nft_af_info in struct nft_table temporarily, as
we still need this to put back reference module reference counter on
table removal.

This patch comes in preparation for the removal of struct nft_af_info.

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

netfilter: nf_tables: validate the expr explicitly after init successfully

When we want to validate the expr's dependency or hooks, we must do two
things to accomplish it. First, write a X_validate callback function
and point ->validate to it. Second, call X_validate in init routine.
This is very common, such as fib, nat, reject expr and so on ...

It is a little ugly, since we will call X_validate in the expr's init
routine, it's better to do it in nf_tables_newexpr. So we can avoid to
do this again and again. After doing this, the second step listed above
is not useful anymore, remove them now.

Patch was tested by nftables/tests/py/nft-test.py and
nftables/tests/shell/run-tests.sh.

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

netfilter: nf_tables: add conntrack dependencies for nat/masq/redir expressions

so that conntrack core will add the needed hooks in this namespace.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: update Arturo Borrero Gonzalez email address

The email address has changed, let's update the copyright statements.

Signed-off-by: Arturo Borrero Gonzalez <arturo@debian.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nft_masq: support port range

Complete masquerading support by allowing port range selection.

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

netfilter: nf_tables: validate hooks in NAT expressions

The user can crash the kernel if it uses any of the existing NAT
expressions from the wrong hook, so add some code to validate this
when loading the rule.

This patch introduces nft_chain_validate_hooks() which is based on
an existing function in the bridge version of the reject expression.

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

netfilter: nf_tables: restrict nat/masq expressions to nat chain type

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>

netfilter: nf_tables: add new nft_masq expression

The nft_masq expression is intended to perform NAT in the masquerade flavour.

We decided to have the masquerade functionality in a separated expression other
than nft_nat.

Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>