flatpak: Sandbox bypass via IOCSTI (incomplete fix for CVE-2017-5226)

An incomplete fix for CVE-2017-5226 was found in flatpak. A sandbox bypass flaw was found in the way bubblewrap, which is used for sandboxing flatpak applications handled the TIOCSTI ioctl. A malicious flatpak application could use this flaw to inject commands into the controlled terminal of the...