staging: rtl8723bs: core: Replace sprintf with scnprintf

The use of sprintf with format string here means that there is a risk
that the writes will go out of bounds, replace it with scnprintf.

In on_action_public_default the variable "cnt" isn't being used for
anything meaningful so remove it.
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Candy Febriyanto <cfebriyanto@gmail.com>
Link: https://lore.kernel.org/r/6c260641164d6856fc4447555fe739124cb27c19.1614610197.git.cfebriyanto@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8723bs/core/rtw_mlme_ext.c

@@ -2084,7 +2084,6 @@ static unsigned int on_action_public_default(union recv_frame *precv_frame, u8 a
 	u8 *frame_body = pframe + sizeof(struct ieee80211_hdr_3addr);
 	u8 token;
 	struct adapter *adapter = precv_frame->u.hdr.adapter;
-	int cnt = 0;
 	char msg[64];
 
 	token = frame_body[2];
@@ -2092,7 +2091,7 @@ static unsigned int on_action_public_default(union recv_frame *precv_frame, u8 a
 	if (rtw_action_public_decache(precv_frame, token) == _FAIL)
 		goto exit;
 
-	cnt += sprintf((msg+cnt), "%s(token:%u)", action_public_str(action), token);
+	scnprintf(msg, sizeof(msg), "%s(token:%u)", action_public_str(action), token);
 	rtw_cfg80211_rx_action(adapter, pframe, frame_len, msg);
 
 	ret = _SUCCESS;

drivers/staging/rtl8723bs/core/rtw_pwrctrl.c

@@ -554,7 +554,7 @@ void LPS_Enter(struct adapter *padapter, const char *msg)
 		/*  Idle for a while if we connect to AP a while ago. */
 		if (pwrpriv->LpsIdleCount >= 2) { /*   4 Sec */
 			if (pwrpriv->pwr_mode == PS_MODE_ACTIVE) {
-				sprintf(buf, "WIFI-%s", msg);
+				scnprintf(buf, sizeof(buf), "WIFI-%s", msg);
 				pwrpriv->bpower_saving = true;
 				rtw_set_ps_mode(padapter, pwrpriv->power_mgnt, padapter->registrypriv.smart_ps, 0, buf);
 			}
@@ -584,7 +584,7 @@ void LPS_Leave(struct adapter *padapter, const char *msg)
 
 	if (pwrpriv->bLeisurePs) {
 		if (pwrpriv->pwr_mode != PS_MODE_ACTIVE) {
-			sprintf(buf, "WIFI-%s", msg);
+			scnprintf(buf, sizeof(buf), "WIFI-%s", msg);
 			rtw_set_ps_mode(padapter, PS_MODE_ACTIVE, 0, 0, buf);
 
 			if (pwrpriv->pwr_mode == PS_MODE_ACTIVE)