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SubjectRe: [PATCH][next] staging: wfx: check for memory allocation failures from wfx_alloc_hif
On Sat, Dec 21, 2019 at 12:15:43AM +0000, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> Currently calls to wfx_alloc_hif are not checking for a null return
> when a memory allocation fails and this leads to null pointer
> dereferencing issues. Fix this by adding null pointer checks and
> returning passing down -ENOMEM errors where necessary. The error
> checking in the current driver is a bit sparse, so this may need
> some extra attention later if required.
>
> Fixes: f95a29d40782 ("staging: wfx: add HIF commands helpers")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> drivers/staging/wfx/hif_tx.c | 6 ++++++
> drivers/staging/wfx/sta.c | 13 +++++++------
> 2 files changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/staging/wfx/hif_tx.c b/drivers/staging/wfx/hif_tx.c
> index 8a34a52dd5b9..d8e159670eae 100644
> --- a/drivers/staging/wfx/hif_tx.c
> +++ b/drivers/staging/wfx/hif_tx.c
> @@ -366,6 +366,9 @@ int hif_set_edca_queue_params(struct wfx_vif *wvif, u16 queue,
> struct hif_req_edca_queue_params *body = wfx_alloc_hif(sizeof(*body),
> &hif);
>

I hate allocations in declaration block. It's way more likely to have
a bug like this where it's missing the NULL check.

> + if (!body)
> + return -ENOMEM;
> +
> WARN_ON(arg->aifs > 255);
> body->aifsn = arg->aifs;
> body->cw_min = cpu_to_le16(arg->cw_min);
> @@ -390,6 +393,9 @@ int hif_set_pm(struct wfx_vif *wvif, bool ps, int dynamic_ps_timeout)
> struct hif_msg *hif;
> struct hif_req_set_pm_mode *body = wfx_alloc_hif(sizeof(*body), &hif);
>
> + if (!body)
> + return -ENOMEM;
> +
> if (ps) {
> body->pm_mode.enter_psm = 1;
> // Firmware does not support more than 128ms
> diff --git a/drivers/staging/wfx/sta.c b/drivers/staging/wfx/sta.c
> index 9a61478d98f8..c08d691fe870 100644
> --- a/drivers/staging/wfx/sta.c
> +++ b/drivers/staging/wfx/sta.c
> @@ -316,6 +316,7 @@ int wfx_conf_tx(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
> {
> struct wfx_dev *wdev = hw->priv;
> struct wfx_vif *wvif = (struct wfx_vif *) vif->drv_priv;
> + int ret = 0;
>
> WARN_ON(queue >= hw->queues);
>
> @@ -326,10 +327,10 @@ int wfx_conf_tx(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
> if (wvif->vif->type == NL80211_IFTYPE_STATION) {
> hif_set_uapsd_info(wvif, wvif->uapsd_mask);
> if (wvif->setbssparams_done && wvif->state == WFX_STATE_STA)
> - wfx_update_pm(wvif);
> + ret = wfx_update_pm(wvif);
> }
> mutex_unlock(&wdev->conf_mutex);
> - return 0;
> + return ret;
> }
>
> int wfx_set_rts_threshold(struct ieee80211_hw *hw, u32 value)
> @@ -1322,7 +1323,7 @@ int wfx_config(struct ieee80211_hw *hw, u32 changed)
> if (changed & IEEE80211_CONF_CHANGE_PS) {
> wvif = NULL;
> while ((wvif = wvif_iterate(wdev, wvif)) != NULL)
> - wfx_update_pm(wvif);
> + ret = wfx_update_pm(wvif);

We reset "ret" on every iteration through the loop and only use the
last value. Probably we should break out of the loop on failure.

> wvif = wdev_to_wvif(wdev, 0);
> }
>

regards,
dan carpenter

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