netfilter: nf_tables: fix a wrong check to skip the inactive rules

BugLink: https://bugs.launchpad.net/bugs/1878232

commit 8fff1722 upstream.

nft_genmask_cur has already done left-shift operator on the gencursor,
so there's no need to do left-shift operator on it again.

Fixes: ea4bd995 ("netfilter: nf_tables: add transaction helper functions")
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

net/netfilter/nf_tables_core.c

@@ -130,7 +130,7 @@ nft_do_chain(struct nft_pktinfo *pkt, void *priv)
 	list_for_each_entry_continue_rcu(rule, &chain->rules, list) {
 
 		/* This rule is not active, skip. */
-		if (unlikely(rule->genmask & (1 << gencursor)))
+		if (unlikely(rule->genmask & gencursor))
 			continue;
 
 		rulenum++;