On Wed, Apr 01, 2020 at 01:03:34PM +0200, Jerome Pouiller wrote:
> From: Jérôme Pouiller <jerome.pouiller@xxxxxxxxxx>
>
> Add a few check on start of hif_join().
>
> Signed-off-by: Jérôme Pouiller <jerome.pouiller@xxxxxxxxxx>
> ---
> drivers/staging/wfx/hif_tx.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/staging/wfx/hif_tx.c b/drivers/staging/wfx/hif_tx.c
> index 77bca43aca42..445906035e9d 100644
> --- a/drivers/staging/wfx/hif_tx.c
> +++ b/drivers/staging/wfx/hif_tx.c
> @@ -297,6 +297,8 @@ int hif_join(struct wfx_vif *wvif, const struct ieee80211_bss_conf *conf,
> struct hif_req_join *body = wfx_alloc_hif(sizeof(*body), &hif);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
We've got an allocation here. It's a mistake to put the allocation in
the declaration block because you're going to forget to check for
failure.
>
> WARN_ON(!conf->basic_rates);
> + WARN_ON(sizeof(body->ssid) < ssidlen);
Put the variable on the left. WARN_ON(ssidlen > sizeof(body->ssid)).
I'm not a big fan of adding this sort of debug code, just audit the
callers to see if it's possible or not.
I have audited the caller for you, and I believe that this condition
*is possible* so we need to return -EINVAL in this situation to prevent
memory corruption.
if (ssidlen > sizeof(body->ssid))
return -EINVAL;
> + WARN(!conf->ibss_joined && !ssidlen, "joining an unknown BSS");
> body->infrastructure_bss_mode = !conf->ibss_joined;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Potential NULL dererefence because of the unchecked allocation.
regards,
dan carpenter
