[nf-next PATCH] netfilter: nf_tables: Fix for extra data in delete notifications

[Phil Sutter <phil@xxxxxx>]

All routines modified in this patch conditionally return early depending
on event value (and other criteria, i.e., chain/flowtable updates).
These checks were defeated by an upfront modification of that variable
for use in nfnl_msg_put(). Restore functionality by avoiding the
modification.

This change is particularly important for user space to distinguish
between a chain/flowtable update removing a hook and full deletion.

Fixes: 28339b21a365 ("netfilter: nf_tables: do not send complete notification of deletions")
Signed-off-by: Phil Sutter <phil@xxxxxx>
---
Channeling this through -next despite it being a fix since unpatched
nft monitor chokes on the shortened delete flowtable notifications.
---
 net/netfilter/nf_tables_api.c | 31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 8952b50b0224..94fd39450672 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/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;
 
@@ -2020,9 +2020,9 @@ 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;
 
@@ -4851,9 +4851,10 @@ 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;
 
@@ -8346,9 +8347,9 @@ 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;
 
@@ -9391,9 +9392,9 @@ 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;
 
-- 
2.49.0