list_for_each_entry_safe() does not work for the async case which runs
under RCU, therefore, split GC logic for catchall in two functions
instead, one for each of the sync and async GC variants.

The catchall sync GC variant never sees a _DEAD bit set on ever, thus,
this handling is removed in such case, moreover, allocate GC sync batch
via GFP_KERNEL.

Fixes: 93995bf4af2c ("netfilter: nf_tables: remove catchall element in GC sync path")
Reported-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Linkui Xiao reported that there's a race condition when ipset swap and destroy is
called, which can lead to crash in add/del/test element operations. Swap then
destroy are usual operations to replace a set with another one in a production
system. The issue can in some cases be reproduced with the script:

ipset create hash_ip1 hash:net family inet hashsize 1024 maxelem 1048576
ipset add hash_ip1 172.20.0.0/16
ipset add hash_ip1 192.168.0.0/16
iptables -A INPUT -m set --match-set hash_ip1 src -j ACCEPT
while [ 1 ]
do
	# ... Ongoing traffic...
        ipset create hash_ip2 hash:net family inet hashsize 1024 maxelem 1048576
        ipset add hash_ip2 172.20.0.0/16
        ipset swap hash_ip1 hash_ip2
        ipset destroy hash_ip2
        sleep 0.05
done

In the race case the possible order of the operations are

	CPU0			CPU1
	ip_set_test
				ipset swap hash_ip1 hash_ip2
				ipset destroy hash_ip2
	hash_net_kadt

Swap replaces hash_ip1 with hash_ip2 and then destroy removes hash_ip2 which
is the original hash_ip1. ip_set_test was called on hash_ip1 and because destroy
removed it, hash_net_kadt crashes.

The fix is to force ip_set_swap() to wait for all readers to finish accessing the
old set pointers by calling synchronize_rcu().

The first version of the patch was written by Linkui Xiao <xiaolinkui@kylinos.cn>.

v2: synchronize_rcu() is moved into ip_set_swap() in order not to burden
    ip_set_destroy() unnecessarily when all sets are destroyed.
v3: Florian Westphal pointed out that all netfilter hooks run with rcu_read_lock() held
    and em_ipset.c wraps the entire ip_set_test() in rcu read lock/unlock pair.
    So there's no need to extend the rcu read locked area in ipset itself.

Closes: https://lore.kernel.org/all/69e7963b-e7f8-3ad0-210-7b86eebf7f78@netfilter.org/
Reported by: Linkui Xiao <xiaolinkui@kylinos.cn>
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

destroy element command bogusly reports ENOENT in case a set element
does not exist. ENOENT errors are skipped, however, err is still set
and propagated to userspace.

 # nft destroy element ip raw BLACKLIST { 1.2.3.4 }
 Error: Could not process rule: No such file or directory
 destroy element ip raw BLACKLIST { 1.2.3.4 }
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Fixes: f80a612dd77c ("netfilter: nf_tables: add support to destroy operation")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

The problem is in nft_byteorder_eval() where we are iterating through a
loop and writing to dst[0], dst[1], dst[2] and so on...  On each
iteration we are writing 8 bytes.  But dst[] is an array of u32 so each
element only has space for 4 bytes.  That means that every iteration
overwrites part of the previous element.

I spotted this bug while reviewing commit caf3ef7468f7 ("netfilter:
nf_tables: prevent OOB access in nft_byteorder_eval") which is a related
issue.  I think that the reason we have not detected this bug in testing
is that most of time we only write one element.

Fixes: ce1e7989d989 ("netfilter: nft_byteorder: provide 64bit le/be conversion")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

The code that uses nft_net has been removed, and the nft_pernet function
is merely obtaining a reference to shared data through the net pointer.
The content of the net pointer is not modified or changed, so both of
them should be removed.

silence the warning:
net/netfilter/nft_set_rbtree.c:627:26: warning: variable ‘nft_net’ set but not used

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7103
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Pablo Neira Ayuso says:

====================
Netfilter fixes for net

The following patchset contains Netfilter fixes for net:

1) Add missing netfilter modules description to fix W=1, from Florian Westphal.

2) Fix catch-all element GC with timeout when use with the pipapo set
   backend, this remained broken since I tried to fix it this summer,
   then another attempt to fix it recently.

3) Add missing IPVS modules descriptions to fix W=1, also from Florian.

4) xt_recent allocated a too small buffer to store an IPv4-mapped IPv6
   address which can be parsed by in6_pton(), from Maciej Zenczykowski.
   Broken for many releases.

5) Skip IPv4-mapped IPv6, IPv4-compat IPv6, site/link local scoped IPv6
   addressses to set up IPv6 NAT redirect, also from Florian. This is
   broken since 2012.

* tag 'nf-23-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
  netfilter: nat: fix ipv6 nat redirect with mapped and scoped addresses
  netfilter: xt_recent: fix (increase) ipv6 literal buffer length
  ipvs: add missing module descriptions
  netfilter: nf_tables: remove catchall element in GC sync path
  netfilter: add missing module descriptions
====================

Link: https://lore.kernel.org/r/20231108155802.84617-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

The ipv6 redirect target was derived from the ipv4 one, i.e. its
identical to a 'dnat' with the first (primary) address assigned to the
network interface.  The code has been moved around to make it usable
from nf_tables too, but its still the same as it was back when this
was added in 2012.

IPv6, however, has different types of addresses, if the 'wrong' address
comes first the redirection does not work.

In Daniels case, the addresses are:
  inet6 ::ffff:192 ...
  inet6 2a01: ...

... so the function attempts to redirect to the mapped address.

Add more checks before the address is deemed correct:
1. If the packets' daddr is scoped, search for a scoped address too
2. skip tentative addresses
3. skip mapped addresses

Use the first address that appears to match our needs.

Reported-by: Daniel Huhardeaux <tech@tootai.net>
Closes: https://lore.kernel.org/netfilter/71be06b8-6aa0-4cf9-9e0b-e2839b01b22f@tootai.net/
Fixes: 115e23ac78f8 ("netfilter: ip6tables: add REDIRECT target")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

in6_pton() supports 'low-32-bit dot-decimal representation'
(this is useful with DNS64/NAT64 networks for example):

  # echo +aaaa:bbbb:cccc:dddd:eeee:ffff:1.2.3.4 > /proc/self/net/xt_recent/DEFAULT
  # cat /proc/self/net/xt_recent/DEFAULT
  src=aaaa:bbbb:cccc:dddd:eeee:ffff:0102:0304 ttl: 0 last_seen: 9733848829 oldest_pkt: 1 9733848829

but the provided buffer is too short:

  # echo +aaaa:bbbb:cccc:dddd:eeee:ffff:255.255.255.255 > /proc/self/net/xt_recent/DEFAULT
  -bash: echo: write error: Invalid argument

Fixes: 079aa88fe717 ("netfilter: xt_recent: IPv6 support")
Signed-off-by: Maciej Żenczykowski <zenczykowski@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

W=1 builds warn on missing MODULE_DESCRIPTION, add them.

Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

The expired catchall element is not deactivated and removed from GC sync
path. This path holds mutex so just call nft_setelem_data_deactivate()
and nft_setelem_catchall_remove() before queueing the GC work.

Fixes: 4a9e12ea7e70 ("netfilter: nft_set_pipapo: call nft_trans_gc_queue_sync() in catchall GC")
Reported-by: lonial con <kongln9170@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>