[PATCH nf-next v3 3/5] netfiler: nf_tables: preemitve fix for audit failure

[Florian Westphal <fw@strlen.de>]

Nftables audit log unfortunately leaks implementation detail, the
transaction log size, to userspace.

Without this, nft_audit.sh selftest fails once subsequenct NEW/DELELEM
transactions can be compressed.

Thus increment the audit counter by the number of elements to keep
the output identical.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 v3: this patch is new to prevent nft_audit.sh from breaking
 after next patch.

 net/netfilter/nf_tables_api.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index d88adbd96ebe..bcb069057a53 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -10373,9 +10373,26 @@ static void nf_tables_commit_audit_free(struct list_head *adl)
 	}
 }
 
+/* Silly, but existing test audit test cases require a count
+ * value derived from the (INTERNAL!) transaction log length.
+ *
+ * Thus, compaction of NEW/DELSETELEM breaks such tests.
+ */
+static unsigned int nf_tables_commit_audit_entrycount(const struct nft_trans *trans)
+{
+	switch (trans->msg_type) {
+	case NFT_MSG_NEWSETELEM:
+	case NFT_MSG_DELSETELEM:
+		return nft_trans_container_elem(trans)->nelems;
+	}
+
+	return 1;
+}
+
 static void nf_tables_commit_audit_collect(struct list_head *adl,
-					   struct nft_table *table, u32 op)
+					   const struct nft_trans *trans, u32 op)
 {
+	const struct nft_table *table = trans->table;
 	struct nft_audit_data *adp;
 
 	list_for_each_entry(adp, adl, list) {
@@ -10385,7 +10402,7 @@ static void nf_tables_commit_audit_collect(struct list_head *adl,
 	WARN_ONCE(1, "table=%s not expected in commit list", table->name);
 	return;
 found:
-	adp->entries++;
+	adp->entries += nf_tables_commit_audit_entrycount(trans);
 	if (!adp->op || adp->op > op)
 		adp->op = op;
 }
@@ -10544,7 +10561,7 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
 
 		nft_ctx_update(&ctx, trans);
 
-		nf_tables_commit_audit_collect(&adl, table, trans->msg_type);
+		nf_tables_commit_audit_collect(&adl, trans, trans->msg_type);
 		switch (trans->msg_type) {
 		case NFT_MSG_NEWTABLE:
 			if (nft_trans_table_update(trans)) {
-- 
2.45.2