browser-system: Use more robust mechanism for starting browser

Use os_exec() to run the external browser to avoid undesired command
line processing for control interface event strings. Previously, it
could have been possible for some of the event strings to include
unsanitized data which is not suitable for system() use.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

src/utils/browser-system.c

@@ -92,7 +92,7 @@ int hs20_web_browser(const char *url)
 		return -1;
 	}
 
-	if (system(cmd) != 0) {
+	if (os_exec("/usr/bin/x-www-browser", url, 0) != 0) {
 		wpa_printf(MSG_INFO, "Failed to launch browser");
 		eloop_cancel_timeout(browser_timeout, NULL, NULL);
 		http_server_deinit(http);