Re: [PATCH v3 net] ipv4: fix error path in fou_create()

From: David Ahern
Date: Sun Aug 08 2021 - 16:05:45 EST


On 8/8/21 1:05 AM, Kangmin Park wrote:
> sock is always NULL when udp_sock_create() is failed and fou is
> always NULL when kzalloc() is failed in error label.
>
> So, add error_sock and error_alloc label and fix the error path
> in those cases.
>
> Signed-off-by: Kangmin Park <l4stpr0gr4m@xxxxxxxxx>
> ---
> v3:
> - change commit message
> - fix error path
> ---
> net/ipv4/fou.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
> index e5f69b0bf3df..f1d99e776bb8 100644
> --- a/net/ipv4/fou.c
> +++ b/net/ipv4/fou.c
> @@ -572,13 +572,13 @@ static int fou_create(struct net *net, struct fou_cfg *cfg,
> /* Open UDP socket */
> err = udp_sock_create(net, &cfg->udp_config, &sock);
> if (err < 0)
> - goto error;
> + goto error_sock;
>
> /* Allocate FOU port structure */
> fou = kzalloc(sizeof(*fou), GFP_KERNEL);
> if (!fou) {
> err = -ENOMEM;
> - goto error;
> + goto error_alloc;
> }
>
> sk = sock->sk;
> @@ -627,9 +627,10 @@ static int fou_create(struct net *net, struct fou_cfg *cfg,
>
> error:
> kfree(fou);
> +error_alloc:
> if (sock)
> udp_tunnel_sock_release(sock);
> -
> +error_sock:
> return err;
> }
>
>

since sock and fou are initialized to NULL, kfree(NULL) is allowed and
there is an 'if (sock)' check before the release, no fix is really needed.