netfilter: nf_tables: Reintroduce shortened deletion notifications

[ Upstream commit a1050dd ]

Restore commit 28339b2 ("netfilter: nf_tables: do not send complete
notification of deletions") and fix it:

- Avoid upfront modification of 'event' variable so the conditionals
  become effective.
- Always include NFTA_OBJ_TYPE attribute in object notifications, user
  space requires it for proper deserialisation.
- Catch DESTROY events, too.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Stable-dep-of: b2f742c ("netfilter: nf_tables: restart set lookup on base_seq change")
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Phil Sutter

net/netfilter/nf_tables_api.c

@@ -1153,9 +1153,9 @@ static int nf_tables_fill_table_info(struct sk_buff *skb, struct net *net,
 {
 	struct nlmsghdr *nlh;
 
-	event = nfnl_msg_type(NFNL_SUBSYS_NFTABLES, event);
-	nlh = nfnl_msg_put(skb, portid, seq, event, flags, family,
-			   NFNETLINK_V0, nft_base_seq(net));
+	nlh = nfnl_msg_put(skb, portid, seq,
+			   nfnl_msg_type(NFNL_SUBSYS_NFTABLES, event),
+			   flags, family, NFNETLINK_V0, nft_base_seq(net));
 	if (!nlh)
 		goto nla_put_failure;
 
@@ -1165,6 +1165,12 @@ static int nf_tables_fill_table_info(struct sk_buff *skb, struct net *net,
 			 NFTA_TABLE_PAD))
 		goto nla_put_failure;
 
+	if (event == NFT_MSG_DELTABLE ||
+	    event == NFT_MSG_DESTROYTABLE) {
+		nlmsg_end(skb, nlh);
+		return 0;
+	}
+
 	if (nla_put_be32(skb, NFTA_TABLE_FLAGS,
 			 htonl(table->flags & NFT_TABLE_F_MASK)))
 		goto nla_put_failure;
@@ -2022,9 +2028,9 @@ static int nf_tables_fill_chain_info(struct sk_buff *skb, struct net *net,
 {
 	struct nlmsghdr *nlh;
 
-	event = nfnl_msg_type(NFNL_SUBSYS_NFTABLES, event);
-	nlh = nfnl_msg_put(skb, portid, seq, event, flags, family,
-			   NFNETLINK_V0, nft_base_seq(net));
+	nlh = nfnl_msg_put(skb, portid, seq,
+			   nfnl_msg_type(NFNL_SUBSYS_NFTABLES, event),
+			   flags, family, NFNETLINK_V0, nft_base_seq(net));
 	if (!nlh)
 		goto nla_put_failure;
 
@@ -2034,6 +2040,13 @@ static int nf_tables_fill_chain_info(struct sk_buff *skb, struct net *net,
 			 NFTA_CHAIN_PAD))
 		goto nla_put_failure;
 
+	if (!hook_list &&
+	    (event == NFT_MSG_DELCHAIN ||
+	     event == NFT_MSG_DESTROYCHAIN)) {
+		nlmsg_end(skb, nlh);
+		return 0;
+	}
+
 	if (nft_is_base_chain(chain)) {
 		const struct nft_base_chain *basechain = nft_base_chain(chain);
 		struct nft_stats __percpu *stats;
@@ -4871,9 +4884,10 @@ static int nf_tables_fill_set(struct sk_buff *skb, const struct nft_ctx *ctx,
 	u32 seq = ctx->seq;
 	int i;
 
-	event = nfnl_msg_type(NFNL_SUBSYS_NFTABLES, event);
-	nlh = nfnl_msg_put(skb, portid, seq, event, flags, ctx->family,
-			   NFNETLINK_V0, nft_base_seq(ctx->net));
+	nlh = nfnl_msg_put(skb, portid, seq,
+			   nfnl_msg_type(NFNL_SUBSYS_NFTABLES, event),
+			   flags, ctx->family, NFNETLINK_V0,
+			   nft_base_seq(ctx->net));
 	if (!nlh)
 		goto nla_put_failure;
 
@@ -4885,6 +4899,12 @@ static int nf_tables_fill_set(struct sk_buff *skb, const struct nft_ctx *ctx,
 			 NFTA_SET_PAD))
 		goto nla_put_failure;
 
+	if (event == NFT_MSG_DELSET ||
+	    event == NFT_MSG_DESTROYSET) {
+		nlmsg_end(skb, nlh);
+		return 0;
+	}
+
 	if (set->flags != 0)
 		if (nla_put_be32(skb, NFTA_SET_FLAGS, htonl(set->flags)))
 			goto nla_put_failure;
@@ -8359,20 +8379,26 @@ static int nf_tables_fill_obj_info(struct sk_buff *skb, struct net *net,
 {
 	struct nlmsghdr *nlh;
 
-	event = nfnl_msg_type(NFNL_SUBSYS_NFTABLES, event);
-	nlh = nfnl_msg_put(skb, portid, seq, event, flags, family,
-			   NFNETLINK_V0, nft_base_seq(net));
+	nlh = nfnl_msg_put(skb, portid, seq,
+			   nfnl_msg_type(NFNL_SUBSYS_NFTABLES, event),
+			   flags, family, NFNETLINK_V0, nft_base_seq(net));
 	if (!nlh)
 		goto nla_put_failure;
 
 	if (nla_put_string(skb, NFTA_OBJ_TABLE, table->name) ||
 	    nla_put_string(skb, NFTA_OBJ_NAME, obj->key.name) ||
+	    nla_put_be32(skb, NFTA_OBJ_TYPE, htonl(obj->ops->type->type)) ||
 	    nla_put_be64(skb, NFTA_OBJ_HANDLE, cpu_to_be64(obj->handle),
 			 NFTA_OBJ_PAD))
 		goto nla_put_failure;
 
-	if (nla_put_be32(skb, NFTA_OBJ_TYPE, htonl(obj->ops->type->type)) ||
-	    nla_put_be32(skb, NFTA_OBJ_USE, htonl(obj->use)) ||
+	if (event == NFT_MSG_DELOBJ ||
+	    event == NFT_MSG_DESTROYOBJ) {
+		nlmsg_end(skb, nlh);
+		return 0;
+	}
+
+	if (nla_put_be32(skb, NFTA_OBJ_USE, htonl(obj->use)) ||
 	    nft_object_dump(skb, NFTA_OBJ_DATA, obj, reset))
 		goto nla_put_failure;
 
@@ -9413,9 +9439,9 @@ static int nf_tables_fill_flowtable_info(struct sk_buff *skb, struct net *net,
 	struct nft_hook *hook;
 	struct nlmsghdr *nlh;
 
-	event = nfnl_msg_type(NFNL_SUBSYS_NFTABLES, event);
-	nlh = nfnl_msg_put(skb, portid, seq, event, flags, family,
-			   NFNETLINK_V0, nft_base_seq(net));
+	nlh = nfnl_msg_put(skb, portid, seq,
+			   nfnl_msg_type(NFNL_SUBSYS_NFTABLES, event),
+			   flags, family, NFNETLINK_V0, nft_base_seq(net));
 	if (!nlh)
 		goto nla_put_failure;
 
@@ -9425,6 +9451,13 @@ static int nf_tables_fill_flowtable_info(struct sk_buff *skb, struct net *net,
 			 NFTA_FLOWTABLE_PAD))
 		goto nla_put_failure;
 
+	if (!hook_list &&
+	    (event == NFT_MSG_DELFLOWTABLE ||
+	     event == NFT_MSG_DESTROYFLOWTABLE)) {
+		nlmsg_end(skb, nlh);
+		return 0;
+	}
+
 	if (nla_put_be32(skb, NFTA_FLOWTABLE_USE, htonl(flowtable->use)) ||
 	    nla_put_be32(skb, NFTA_FLOWTABLE_FLAGS, htonl(flowtable->data.flags)))
 		goto nla_put_failure;