libertas_tf: avoid a null dereference in pointer priv

Currently there is a check if priv is null when calling lbtf_remove_card
but not in a previous call to if_usb_reset_dev that can also dereference
priv.  Fix this by also only calling lbtf_remove_card if priv is null.

It is noteable that there don't seem to be any bugs reported that the
null pointer dereference has ever occurred, so I'm not sure if the null
check is required, but since we're doing a null check anyway it should
be done for both function calls.

Addresses-Coverity: ("Dereference before null check")
Fixes: baa0280f08c7 ("libertas_tf: don't defer firmware loading until start()")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200501173900.296658-1-colin.king@canonical.com

diff --git a/drivers/net/wireless/marvell/libertas_tf/if_usb.c b/drivers/net/wireless/marvell/libertas_tf/if_usb.c
index 25ac9db35dbfe5b04060327566aa00399b5e2f67..bedc0921508840343deeb804277470f9f1d30d2b 100644 (file)
--- a/drivers/net/wireless/marvell/libertas_tf/if_usb.c
+++ b/drivers/net/wireless/marvell/libertas_tf/if_usb.c
@@ -247,10 +247,10 @@ static void if_usb_disconnect(struct usb_interface *intf)
 
        lbtf_deb_enter(LBTF_DEB_MAIN);
 
-       if_usb_reset_device(priv);
-
-       if (priv)
+       if (priv) {
+               if_usb_reset_device(priv);
                lbtf_remove_card(priv);
+       }
 
        /* Unlink and free urb */
        if_usb_free(cardp);