netfilter: nf_tables: Deduplicate nft_register_obj audit logs

When adding/updating an object, the transaction handler emits suitable
audit log entries already, the one in nft_obj_notify() is redundant. To
fix that (and retain the audit logging from objects' 'update' callback),
Introduce an "audit log free" variant for internal use.

Fixes: c520292 ("audit: log nftables configuration change events once per table")
Signed-off-by: Phil Sutter <[email protected]>
Reviewed-by: Richard Guy Briggs <[email protected]>
Acked-by: Paul Moore <[email protected]> (Audit)
Signed-off-by: Florian Westphal <[email protected]>

Author: Phil Sutter

net/netfilter/nf_tables_api.c

@@ -7871,24 +7871,14 @@ static int nf_tables_delobj(struct sk_buff *skb, const struct nfnl_info *info,
 	return nft_delobj(&ctx, obj);
 }
 
-void nft_obj_notify(struct net *net, const struct nft_table *table,
-		    struct nft_object *obj, u32 portid, u32 seq, int event,
-		    u16 flags, int family, int report, gfp_t gfp)
+static void
+__nft_obj_notify(struct net *net, const struct nft_table *table,
+		 struct nft_object *obj, u32 portid, u32 seq, int event,
+		 u16 flags, int family, int report, gfp_t gfp)
 {
 	struct nftables_pernet *nft_net = nft_pernet(net);
 	struct sk_buff *skb;
 	int err;
-	char *buf = kasprintf(gfp, "%s:%u",
-			      table->name, nft_net->base_seq);
-
-	audit_log_nfcfg(buf,
-			family,
-			obj->handle,
-			event == NFT_MSG_NEWOBJ ?
-				 AUDIT_NFT_OP_OBJ_REGISTER :
-				 AUDIT_NFT_OP_OBJ_UNREGISTER,
-			gfp);
-	kfree(buf);
 
 	if (!report &&
 	    !nfnetlink_has_listeners(net, NFNLGRP_NFTABLES))
@@ -7911,13 +7901,35 @@ void nft_obj_notify(struct net *net, const struct nft_table *table,
 err:
 	nfnetlink_set_err(net, portid, NFNLGRP_NFTABLES, -ENOBUFS);
 }
+
+void nft_obj_notify(struct net *net, const struct nft_table *table,
+		    struct nft_object *obj, u32 portid, u32 seq, int event,
+		    u16 flags, int family, int report, gfp_t gfp)
+{
+	struct nftables_pernet *nft_net = nft_pernet(net);
+	char *buf = kasprintf(gfp, "%s:%u",
+			      table->name, nft_net->base_seq);
+
+	audit_log_nfcfg(buf,
+			family,
+			obj->handle,
+			event == NFT_MSG_NEWOBJ ?
+				 AUDIT_NFT_OP_OBJ_REGISTER :
+				 AUDIT_NFT_OP_OBJ_UNREGISTER,
+			gfp);
+	kfree(buf);
+
+	__nft_obj_notify(net, table, obj, portid, seq, event,
+			 flags, family, report, gfp);
+}
 EXPORT_SYMBOL_GPL(nft_obj_notify);
 
 static void nf_tables_obj_notify(const struct nft_ctx *ctx,
 				 struct nft_object *obj, int event)
 {
-	nft_obj_notify(ctx->net, ctx->table, obj, ctx->portid, ctx->seq, event,
-		       ctx->flags, ctx->family, ctx->report, GFP_KERNEL);
+	__nft_obj_notify(ctx->net, ctx->table, obj, ctx->portid,
+			 ctx->seq, event, ctx->flags, ctx->family,
+			 ctx->report, GFP_KERNEL);
 }
 
 /*

tools/testing/selftests/netfilter/nft_audit.sh

@@ -85,6 +85,26 @@ do_test "nft add set t1 s2 $setblock; add set t1 s3 { $settype; }" \
 do_test "nft add element t1 s3 $setelem" \
 "table=t1 family=2 entries=3 op=nft_register_setelem"
 
+# adding counters
+
+do_test 'nft add counter t1 c1' \
+'table=t1 family=2 entries=1 op=nft_register_obj'
+
+do_test 'nft add counter t2 c1; add counter t2 c2' \
+'table=t2 family=2 entries=2 op=nft_register_obj'
+
+# adding/updating quotas
+
+do_test 'nft add quota t1 q1 { 10 bytes }' \
+'table=t1 family=2 entries=1 op=nft_register_obj'
+
+do_test 'nft add quota t2 q1 { 10 bytes }; add quota t2 q2 { 10 bytes }' \
+'table=t2 family=2 entries=2 op=nft_register_obj'
+
+# changing the quota value triggers obj update path
+do_test 'nft add quota t1 q1 { 20 bytes }' \
+'table=t1 family=2 entries=1 op=nft_register_obj'
+
 # resetting rules
 
 do_test 'nft reset rules t1 c2' \