Re: [PATCH] staging: ks7010_sdio: fix NULL pointer dereference and memory leak

From: Dan Carpenter
Date: Thu Apr 12 2018 - 11:18:37 EST


I added Colin to the Cc list.

On Thu, Apr 12, 2018 at 09:30:09AM -0500, Gustavo A. R. Silva wrote:
> priv is being dereferenced when it is still null, hence there is an
> explicit null pointer dereference at line 935: free_netdev(priv->net_dev)
>
> Also, memory allocated for netdev at line 854:
> netdev = alloc_etherdev(sizeof(*priv));
> is not being free'd, hence there is a memory leak.
>
> Fix this by null checking priv before dererefencing it and free netdev
> before return.
>
> Addresses-Coverity-ID: 1467844 ("Explicit null dereferenced")
> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
> ---
> drivers/staging/ks7010/ks7010_sdio.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/ks7010/ks7010_sdio.c b/drivers/staging/ks7010/ks7010_sdio.c
> index b8f55a1..f5d4c62 100644
> --- a/drivers/staging/ks7010/ks7010_sdio.c
> +++ b/drivers/staging/ks7010/ks7010_sdio.c
> @@ -932,8 +932,12 @@ static int ks7010_sdio_probe(struct sdio_func *func,
> return 0;
>
> err_free_netdev:
> - free_netdev(priv->net_dev);
> - card->priv = NULL;
> + if (priv) {
> + free_netdev(priv->net_dev);
> + card->priv = NULL;

This isn't required because the next thing we do to card is kfree(card).

> + } else {
> + free_netdev(netdev);
> + }


That's too complicated. Just do:

err_free_netdev:
free_netdev(net_dev);

err_release_irq:
...

Please send a v2 patch.

regards,
dan carpenter