[nf PATCH 2/3] netfilter: nf_tables: Deduplicate nft_register_obj audit logs

Phil Sutter
2023-09-23T01:54:00Z

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: c520292f29b80 ("audit: log nftables configuration change events once per table")
Signed-off-by: Phil Sutter <phil@nwl.cc>
---
net/netfilter/nf_tables_api.c | 44 ++++++++++++-------
.../testing/selftests/netfilter/nft_audit.sh | 20 +++++++++
2 files changed, 48 insertions(+), 16 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 0e5d9bdba82b8..48d50df950a18 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -8046,24 +8046,14 @@ 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))
@@ -8086,13 +8076,35 @@ 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);
}

/*
diff --git a/tools/testing/selftests/netfilter/nft_audit.sh b/tools/testing/selftests/netfilter/nft_audit.sh
index 0b3255e7b3538..bb34329e02a7f 100755
--- a/tools/testing/selftests/netfilter/nft_audit.sh
+++ b/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' \
--
2.41.0