netfilter: nf_tables: sanitize nft_set_desc_concat_parse()

netfilter: nf_tables: sanitize nft_set_desc_concat_parse()

BugLink: https://bugs.launchpad.net/bugs/1976363
Add several sanity checks for nft_set_desc_concat_parse():

- validate desc->field_count not larger than desc->field_len array.
- field length cannot be larger than desc->field_len (ie. U8_MAX)
- total length of the concatenation cannot be larger than register array.

Joint work with Florian Westphal.

Fixes: f3a2181e16f1 ("netfilter: nf_tables: Support for sets with multiple ranged fields")
Reported-by: <zhangziming.zzm@antgroup.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
(cherry picked from commit fecf31ee395b0295f2d7260aa29946b7605f7c85 net.git)
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Acked-by: Andrea Righi <andrea.righi@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>