[PATCH -stable,4.19.x 40/40] netfilter: nf_tables: discard table flag update with pending basechain deletion

[Pablo Neira Ayuso <pablo@netfilter.org>]

commit 1bc83a019bbe268be3526406245ec28c2458a518 upstream.

Hook unregistration is deferred to the commit phase, same occurs with
hook updates triggered by the table dormant flag. When both commands are
combined, this results in deleting a basechain while leaving its hook
still registered in the core.

Fixes: 179d9ba5559a ("netfilter: nf_tables: fix table flag updates")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/netfilter/nf_tables_api.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 73ab0795ed55..198e4a89df48 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -877,6 +877,24 @@ static void nf_tables_table_disable(struct net *net, struct nft_table *table)
 #define __NFT_TABLE_F_UPDATE		(__NFT_TABLE_F_WAS_DORMANT | \
 					 __NFT_TABLE_F_WAS_AWAKEN)
 
+static bool nft_table_pending_update(const struct nft_ctx *ctx)
+{
+	struct nftables_pernet *nft_net = net_generic(ctx->net, nf_tables_net_id);
+	struct nft_trans *trans;
+
+	if (ctx->table->flags & __NFT_TABLE_F_UPDATE)
+		return true;
+
+	list_for_each_entry(trans, &nft_net->commit_list, list) {
+		if (trans->ctx.table == ctx->table &&
+		    trans->msg_type == NFT_MSG_DELCHAIN &&
+		    nft_is_base_chain(trans->ctx.chain))
+			return true;
+	}
+
+	return false;
+}
+
 static int nf_tables_updtable(struct nft_ctx *ctx)
 {
 	struct nft_trans *trans;
@@ -894,7 +912,7 @@ static int nf_tables_updtable(struct nft_ctx *ctx)
 		return 0;
 
 	/* No dormant off/on/off/on games in single transaction */
-	if (ctx->table->flags & __NFT_TABLE_F_UPDATE)
+	if (nft_table_pending_update(ctx))
 		return -EINVAL;
 
 	trans = nft_trans_alloc(ctx, NFT_MSG_NEWTABLE,
-- 
2.30.2