netdev - [PATCH net v2] openvswitch: fix memory leak at failed datapath creation

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Date:   Thu, 25 Aug 2022 05:03:26 +0300
From:   Andrey Zhadchenko <andrey.zhadchenko@...tuozzo.com>
To:     netdev@...r.kernel.org
Cc:     dev@...nvswitch.org, pshelar@....org, davem@...emloft.net,
        edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com,
        aconole@...hat.com, mark.d.gray@...hat.com, i.maximets@....org
Subject: [PATCH net v2] openvswitch: fix memory leak at failed datapath creation

ovs_dp_cmd_new()->ovs_dp_change()->ovs_dp_set_upcall_portids()
allocates array via kmalloc.
If for some reason new_vport() fails during ovs_dp_cmd_new()
dp->upcall_portids must be freed.
Add missing kfree.

Kmemleak example:
unreferenced object 0xffff88800c382500 (size 64):
  comm "dump_state", pid 323, jiffies 4294955418 (age 104.347s)
  hex dump (first 32 bytes):
    5e c2 79 e4 1f 7a 38 c7 09 21 38 0c 80 88 ff ff  ^.y..z8..!8.....
    03 00 00 00 0a 00 00 00 14 00 00 00 28 00 00 00  ............(...
  backtrace:
    [<0000000071bebc9f>] ovs_dp_set_upcall_portids+0x38/0xa0
    [<000000000187d8bd>] ovs_dp_change+0x63/0xe0
    [<000000002397e446>] ovs_dp_cmd_new+0x1f0/0x380
    [<00000000aa06f36e>] genl_family_rcv_msg_doit+0xea/0x150
    [<000000008f583bc4>] genl_rcv_msg+0xdc/0x1e0
    [<00000000fa10e377>] netlink_rcv_skb+0x50/0x100
    [<000000004959cece>] genl_rcv+0x24/0x40
    [<000000004699ac7f>] netlink_unicast+0x23e/0x360
    [<00000000c153573e>] netlink_sendmsg+0x24e/0x4b0
    [<000000006f4aa380>] sock_sendmsg+0x62/0x70
    [<00000000d0068654>] ____sys_sendmsg+0x230/0x270
    [<0000000012dacf7d>] ___sys_sendmsg+0x88/0xd0
    [<0000000011776020>] __sys_sendmsg+0x59/0xa0
    [<000000002e8f2dc1>] do_syscall_64+0x3b/0x90
    [<000000003243e7cb>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fixes: b83d23a2a38b ("openvswitch: Introduce per-cpu upcall dispatch")
Acked-by: Aaron Conole <aconole@...hat.com>
Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko@...tuozzo.com>
---
v2:
Remove the unnecessary if(rcu_dereference_raw(dp->upcall_portids))

 net/openvswitch/datapath.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 7e8a39a35627..7179d254b08b 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -1802,7 +1802,7 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info)
 				ovs_dp_reset_user_features(skb, info);
 		}
 
-		goto err_unlock_and_destroy_meters;
+		goto err_destroy_portids;
 	}
 
 	err = ovs_dp_cmd_fill_info(dp, reply, info->snd_portid,
@@ -1817,6 +1817,8 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info)
 	ovs_notify(&dp_datapath_genl_family, reply, info);
 	return 0;
 
+err_destroy_portids:
+	kfree(rcu_dereference_raw(dp->upcall_portids));
 err_unlock_and_destroy_meters:
 	ovs_unlock();
 	ovs_meters_exit(dp);
-- 
2.31.1