linux-kernel - [PATCH 5.10 152/158] netfilter: nf_tables: fix audit memory leak in nf_tables

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Message-Id: <20220823080051.934545112@linuxfoundation.org>
Date:   Tue, 23 Aug 2022 10:28:04 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, syzbot <syzkaller@...glegroups.com>,
        kernel test robot <lkp@...el.com>,
        Dongliang Mu <mudongliangabcd@...il.com>,
        Pablo Neira Ayuso <pablo@...filter.org>
Subject: [PATCH 5.10 152/158] netfilter: nf_tables: fix audit memory leak in nf_tables_commit

From: Dongliang Mu <mudongliangabcd@...il.com>

commit cfbe3650dd3ef2ea9a4420ca89d9a4df98af3fb6 upstream.

In nf_tables_commit, if nf_tables_commit_audit_alloc fails, it does not
free the adp variable.

Fix this by adding nf_tables_commit_audit_free which frees
the linked list with the head node adl.

backtrace:
  kmalloc include/linux/slab.h:591 [inline]
  kzalloc include/linux/slab.h:721 [inline]
  nf_tables_commit_audit_alloc net/netfilter/nf_tables_api.c:8439 [inline]
  nf_tables_commit+0x16e/0x1760 net/netfilter/nf_tables_api.c:8508
  nfnetlink_rcv_batch+0x512/0xa80 net/netfilter/nfnetlink.c:562
  nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:634 [inline]
  nfnetlink_rcv+0x1fa/0x220 net/netfilter/nfnetlink.c:652
  netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
  netlink_unicast+0x2c7/0x3e0 net/netlink/af_netlink.c:1340
  netlink_sendmsg+0x36b/0x6b0 net/netlink/af_netlink.c:1929
  sock_sendmsg_nosec net/socket.c:702 [inline]
  sock_sendmsg+0x56/0x80 net/socket.c:722

Reported-by: syzbot <syzkaller@...glegroups.com>
Reported-by: kernel test robot <lkp@...el.com>
Fixes: c520292f29b8 ("audit: log nftables configuration change events once per table")
Signed-off-by: Dongliang Mu <mudongliangabcd@...il.com>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 net/netfilter/nf_tables_api.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -7819,6 +7819,16 @@ static int nf_tables_commit_audit_alloc(
 	return 0;
 }
 
+static void nf_tables_commit_audit_free(struct list_head *adl)
+{
+	struct nft_audit_data *adp, *adn;
+
+	list_for_each_entry_safe(adp, adn, adl, list) {
+		list_del(&adp->list);
+		kfree(adp);
+	}
+}
+
 static void nf_tables_commit_audit_collect(struct list_head *adl,
 					   struct nft_table *table, u32 op)
 {
@@ -7882,6 +7892,7 @@ static int nf_tables_commit(struct net *
 		ret = nf_tables_commit_audit_alloc(&adl, trans->ctx.table);
 		if (ret) {
 			nf_tables_commit_chain_prepare_cancel(net);
+			nf_tables_commit_audit_free(&adl);
 			return ret;
 		}
 		if (trans->msg_type == NFT_MSG_NEWRULE ||
@@ -7891,6 +7902,7 @@ static int nf_tables_commit(struct net *
 			ret = nf_tables_commit_chain_prepare(net, chain);
 			if (ret < 0) {
 				nf_tables_commit_chain_prepare_cancel(net);
+				nf_tables_commit_audit_free(&adl);
 				return ret;
 			}
 		}