Commit cfbe3650 authored Jul 14, 2021 by Dongliang Mu Committed by Pablo Neira Ayuso Jul 17, 2021

netfilter: nf_tables: fix audit memory leak in nf_tables_commit



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@googlegroups.com>
Reported-by: kernel test robot <lkp@intel.com>
Fixes: c520292f ("audit: log nftables configuration change events once per table")
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

parent 5f119ba1

net/netfilter/nf_tables_api.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -8445,6 +8445,16 @@ static int nf_tables_commit_audit_alloc(struct list_head *adl,
		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)
		{
		@@ -8509,6 +8519,7 @@ static int nf_tables_commit(struct net net, struct sk_buff skb)
		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 \|\|
		@@ -8518,6 +8529,7 @@ static int nf_tables_commit(struct net net, struct sk_buff skb)
		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;
		}
		}