netfilter: nf_tables: Audit log rule reset

JIRA: https://issues.redhat.com/browse/RHEL-9127

This patch is a backport of the following upstream commit:
commit ea078ae
Author: Phil Sutter <phil@nwl.cc>
Date:   Tue Aug 29 19:51:58 2023 +0200

    netfilter: nf_tables: Audit log rule reset

    Resetting rules' stateful data happens outside of the transaction logic,
    so 'get' and 'dump' handlers have to emit audit log entries themselves.

    Fixes: 8daa8fd ("netfilter: nf_tables: Introduce NFT_MSG_GETRULE_RESET")
    Signed-off-by: Phil Sutter <phil@nwl.cc>
    Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
    Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Signed-off-by: Ricardo Robaina <rrobaina@redhat.com>

Author: rprobaina

include/linux/audit.h

@@ -118,6 +118,7 @@ enum audit_nfcfgop {
 	AUDIT_NFT_OP_FLOWTABLE_REGISTER,
 	AUDIT_NFT_OP_FLOWTABLE_UNREGISTER,
 	AUDIT_NFT_OP_SETELEM_RESET,
+	AUDIT_NFT_OP_RULE_RESET,
 	AUDIT_NFT_OP_INVALID,
 };
 

kernel/auditsc.c

@@ -144,6 +144,7 @@ static const struct audit_nfcfgop_tab audit_nfcfgs[] = {
 	{ AUDIT_NFT_OP_FLOWTABLE_REGISTER,	"nft_register_flowtable"   },
 	{ AUDIT_NFT_OP_FLOWTABLE_UNREGISTER,	"nft_unregister_flowtable" },
 	{ AUDIT_NFT_OP_SETELEM_RESET,		"nft_reset_setelem"        },
+	{ AUDIT_NFT_OP_RULE_RESET,		"nft_reset_rule"           },
 	{ AUDIT_NFT_OP_INVALID,			"nft_invalid"		   },
 };
 

net/netfilter/nf_tables_api.c

@@ -3089,6 +3089,18 @@ static void nf_tables_rule_notify(const struct nft_ctx *ctx,
 	nfnetlink_set_err(ctx->net, ctx->portid, NFNLGRP_NFTABLES, -ENOBUFS);
 }
 
+static void audit_log_rule_reset(const struct nft_table *table,
+				 unsigned int base_seq,
+				 unsigned int nentries)
+{
+	char *buf = kasprintf(GFP_ATOMIC, "%s:%u",
+			      table->name, base_seq);
+
+	audit_log_nfcfg(buf, table->family, nentries,
+			AUDIT_NFT_OP_RULE_RESET, GFP_ATOMIC);
+	kfree(buf);
+}
+
 struct nft_rule_dump_ctx {
 	char *table;
 	char *chain;
@@ -3195,6 +3207,9 @@ static int nf_tables_dump_rules(struct sk_buff *skb,
 done:
 	rcu_read_unlock();
 
+	if (reset && idx > cb->args[0])
+		audit_log_rule_reset(table, cb->seq, idx - cb->args[0]);
+
 	cb->args[0] = idx;
 	return skb->len;
 }
@@ -3302,6 +3317,9 @@ static int nf_tables_getrule(struct sk_buff *skb, const struct nfnl_info *info,
 	if (err < 0)
 		goto err_fill_rule_info;
 
+	if (reset)
+		audit_log_rule_reset(table, nft_pernet(net)->base_seq, 1);
+
 	return nfnetlink_unicast(skb2, net, NETLINK_CB(skb).portid);
 
 err_fill_rule_info: