[Devel] [PATCH RH9 2/4] openvswitch: fix memory leak at failed datapath creation

[Pavel Tikhomirov]

On 25.04.2023 18:11, Andrey Zhadchenko wrote:
> 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 at redhat.com>
> Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko at virtuozzo.com>
> Link: https://lore.kernel.org/r/20220825020326.664073-1-andrey.zhadchenko@virtuozzo.com
> Signed-off-by: Jakub Kicinski <kuba at kernel.org>
> 
> (cherry picked from ms commit a87406f4adee9c53b311d8a1ba2849c69e29a6d0)

Do we have jira issue for it?

> Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko at virtuozzo.com>
> ---
>   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..6c9d153afbee 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);

-- 
Best regards, Tikhomirov Pavel
Senior Software Developer, Virtuozzo.