Check os_snprintf() result more consistently - more checks

Add more os_snprintf() result validation checks.

Signed-off-by: Jouni Malinen <j@w1.fi>

src/ap/sta_info.c

@@ -1120,6 +1120,8 @@ int ap_sta_flags_txt(u32 flags, char *buf, size_t buflen)
 			  (flags & WLAN_STA_VHT ? "[VHT]" : ""),
 			  (flags & WLAN_STA_WNM_SLEEP_MODE ?
 			   "[WNM_SLEEP_MODE]" : ""));
+	if (os_snprintf_error(buflen, res))
+		res = -1;
 
 	return res;
 }

wpa_supplicant/ap.c

@@ -812,9 +812,14 @@ int wpa_supplicant_ap_wps_pin(struct wpa_supplicant *wpa_s, const u8 *bssid,
 	if (pin == NULL) {
 		unsigned int rpin = wps_generate_pin();
 		ret_len = os_snprintf(buf, buflen, "%08d", rpin);
+		if (os_snprintf_error(buflen, ret_len))
+			return -1;
 		pin = buf;
-	} else
+	} else if (buf) {
 		ret_len = os_snprintf(buf, buflen, "%s", pin);
+		if (os_snprintf_error(buflen, ret_len))
+			return -1;
+	}
 
 	ret = hostapd_wps_add_pin(wpa_s->ap_iface->bss[0], bssid, "any", pin,
 				  timeout);

wpa_supplicant/ctrl_iface.c

@@ -5859,6 +5859,8 @@ static int wpa_supplicant_driver_cmd(struct wpa_supplicant *wpa_s, char *cmd,
 			}
 		}
 		ret = os_snprintf(buf, buflen, "%s\n", "OK");
+		if (os_snprintf_error(buflen, ret))
+			ret = -1;
 	}
 	return ret;
 }