netfilter: nf_tables: release batch on table validation from abort path

jira VULN-4969
subsystem-sync netfilter:nf_tables 4.18.0-553.16.1
commit-author Pablo Neira Ayuso <pablo@netfilter.org>
commit a45e688

Unlike early commit path stage which triggers a call to abort, an
explicit release of the batch is required on abort, otherwise mutex is
released and commit_list remains in place.

Add WARN_ON_ONCE to ensure commit_list is empty from the abort path
before releasing the mutex.

After this patch, commit_list is always assumed to be empty before
grabbing the mutex, therefore

  03c1f1e ("netfilter: Cleanup nft_net->module_list from nf_tables_exit_net()")

only needs to release the pending modules for registration.

	Cc: stable@vger.kernel.org
Fixes: c0391b6 ("netfilter: nf_tables: missing validation from the abort path")
	Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
(cherry picked from commit a45e688)
	Signed-off-by: Greg Rose <g.v.rose@ciq.com>

Author: gvrose8192

net/netfilter/nf_tables_api.c

@@ -8465,10 +8465,11 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
 	struct nft_trans *trans, *next;
 	LIST_HEAD(set_update_list);
 	struct nft_trans_elem *te;
+	int err = 0;
 
 	if (action == NFNL_ABORT_VALIDATE &&
 	    nf_tables_validate(net) < 0)
-		return -EAGAIN;
+		err = -EAGAIN;
 
 	list_for_each_entry_safe_reverse(trans, next, &net->nft.commit_list,
 					 list) {
@@ -8617,7 +8618,7 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
 	else
 		nf_tables_module_autoload_cleanup(net);
 
-	return 0;
+	return err;
 }
 
 static void nf_tables_cleanup(struct net *net)
@@ -8636,6 +8637,8 @@ static int nf_tables_abort(struct net *net, struct sk_buff *skb,
 	ret = __nf_tables_abort(net, action);
 	nft_gc_seq_end(nft_net, gc_seq);
 
+	WARN_ON_ONCE(!list_empty(&net->nft.commit_list));
+
 	mutex_unlock(&net->nft_commit_mutex);
 
 	return ret;
@@ -9287,9 +9290,10 @@ static void __net_exit nf_tables_exit_net(struct net *net)
 
 	gc_seq = nft_gc_seq_begin(nft_net);
 
-	if (!list_empty(&net->nft.commit_list) ||
-            !list_empty(&net->nft_module_list))
-                __nf_tables_abort(net, NFNL_ABORT_NONE);
+	WARN_ON_ONCE(!list_empty(&net->nft.commit_list));
+
+	if (!list_empty(&net->nft_module_list))
+		nf_tables_module_autoload_cleanup(net);
 
 	__nft_release_tables(net);