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Re: Bug#664784: ITP: sandbox -- A helper utility to run programs in a sandboxed environment

On 20/03/12 20:11, Ivan Krylov wrote:
>  Sandbox is a library (and helper utility) to run programs in a "sandboxed"
>  environment.  This is used as a QA measure to try and prevent applications from
>  modifying files they should not.

Is sandbox secure (in the sense that an actively malicious program run
inside a sandbox, whose author is fully aware of how sandbox works, is
prevented from breaking out), or does it only protect against common
mistakes and not against deliberate abuse?

If sandbox is not suitable for sandboxing deliberately malicious
programs, I think it's important for its package description to say so.

(For instance, chroot(2) is not secure against malicious programs with
CAP_SYS_CHROOT. If I understand it correctly, schroot, as commonly used
in Debian infrastructure, is secure if its user cannot get root
privileges and all setuid-root binaries inside the chroot are secure.)

>  For people who are familiar with the Debian "fakeroot" project or the RPM based
>  "InstallWatch", sandbox is in the same vein of projects.

Is it really, though? fakeroot is just an LD_PRELOAD hack which pretends
to have root privileges: it doesn't allow the program to do anything
that it couldn't already do (its real privileges are those of the user
running it). As a result, fakeroot "fails safe" if a privileged action
isn't supported by fakeroot - it just won't work. In contrast, a
mechanism that gives real root privileges will "fail open", and allow
all privileged actions that it doesn't specifically deny.


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