netfilter: nftables: update table flags from the commit phase

jira VULN-597
subsystem-sync netfilter:nf_tables 4.18.0-534
commit-author Pablo Neira Ayuso <[email protected]>
commit 0ce7cf4

Do not update table flags from the preparation phase. Store the flags
update into the transaction, then update the flags from the commit
phase.

	Signed-off-by: Pablo Neira Ayuso <[email protected]>
(cherry picked from commit 0ce7cf4)
	Signed-off-by: Greg Rose <[email protected]>

Author: gvrose8192

include/net/netfilter/nf_tables.h

@@ -1449,13 +1449,16 @@ struct nft_trans_chain {
 
 struct nft_trans_table {
 	bool				update;
-	bool				enable;
+	u8				state;
+	u32				flags;
 };
 
 #define nft_trans_table_update(trans)	\
 	(((struct nft_trans_table *)trans->data)->update)
-#define nft_trans_table_enable(trans)	\
-	(((struct nft_trans_table *)trans->data)->enable)
+#define nft_trans_table_state(trans)	\
+	(((struct nft_trans_table *)trans->data)->state)
+#define nft_trans_table_flags(trans)	\
+	(((struct nft_trans_table *)trans->data)->flags)
 
 struct nft_trans_elem {
 	struct nft_set			*set;

net/netfilter/nf_tables_api.c

@@ -945,6 +945,12 @@ static void nf_tables_table_disable(struct net *net, struct nft_table *table)
 	nft_table_disable(net, table, 0);
 }
 
+enum {
+	NFT_TABLE_STATE_UNCHANGED	= 0,
+	NFT_TABLE_STATE_DORMANT,
+	NFT_TABLE_STATE_WAKEUP
+};
+
 static int nf_tables_updtable(struct nft_ctx *ctx)
 {
 	struct nft_trans *trans;
@@ -968,19 +974,17 @@ static int nf_tables_updtable(struct nft_ctx *ctx)
 
 	if ((flags & NFT_TABLE_F_DORMANT) &&
 	    !(ctx->table->flags & NFT_TABLE_F_DORMANT)) {
-		nft_trans_table_enable(trans) = false;
+		nft_trans_table_state(trans) = NFT_TABLE_STATE_DORMANT;
 	} else if (!(flags & NFT_TABLE_F_DORMANT) &&
 		   ctx->table->flags & NFT_TABLE_F_DORMANT) {
-		ctx->table->flags &= ~NFT_TABLE_F_DORMANT;
 		ret = nf_tables_table_enable(ctx->net, ctx->table);
 		if (ret >= 0)
-			nft_trans_table_enable(trans) = true;
-		else
-			ctx->table->flags |= NFT_TABLE_F_DORMANT;
+			nft_trans_table_state(trans) = NFT_TABLE_STATE_WAKEUP;
 	}
 	if (ret < 0)
 		goto err;
 
+	nft_trans_table_flags(trans) = flags;
 	nft_trans_table_update(trans) = true;
 	list_add_tail(&trans->list, &ctx->net->nft.commit_list);
 	return 0;
@@ -8226,11 +8230,10 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
 		switch (trans->msg_type) {
 		case NFT_MSG_NEWTABLE:
 			if (nft_trans_table_update(trans)) {
-				if (!nft_trans_table_enable(trans)) {
-					nf_tables_table_disable(net,
-								trans->ctx.table);
-					trans->ctx.table->flags |= NFT_TABLE_F_DORMANT;
-				}
+				if (nft_trans_table_state(trans) == NFT_TABLE_STATE_DORMANT)
+					nf_tables_table_disable(net, trans->ctx.table);
+
+				trans->ctx.table->flags = nft_trans_table_flags(trans);
 			} else {
 				nft_clear(net, trans->ctx.table);
 			}
@@ -8452,11 +8455,9 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
 		switch (trans->msg_type) {
 		case NFT_MSG_NEWTABLE:
 			if (nft_trans_table_update(trans)) {
-				if (nft_trans_table_enable(trans)) {
-					nf_tables_table_disable(net,
-								trans->ctx.table);
-					trans->ctx.table->flags |= NFT_TABLE_F_DORMANT;
-				}
+				if (nft_trans_table_state(trans) == NFT_TABLE_STATE_WAKEUP)
+					nf_tables_table_disable(net, trans->ctx.table);
+
 				nft_trans_destroy(trans);
 			} else {
 				list_del_rcu(&trans->ctx.table->list);