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: c520292f29b8 ("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>

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index de182d1f7c4eda016adac210e1a6b7901dd4d81d..081437dd75b7eba8bb71ac4b9ee46a6ab5c7fd40 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -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;
                        }
                }