[Virtio-fs] [PATCH 1/2] virtiofsd: move to an empty network namespace

[Dr. David Alan Gilbert]

* Stefan Hajnoczi (stefanha at redhat.com) wrote:
> If the process is compromised there should be no network access.  Use an
> empty network namespace to sandbox networking.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha at redhat.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert at redhat.com>

> ---
>  contrib/virtiofsd/passthrough_ll.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/contrib/virtiofsd/passthrough_ll.c b/contrib/virtiofsd/passthrough_ll.c
> index 84b60d85bd..c27ff7d800 100644
> --- a/contrib/virtiofsd/passthrough_ll.c
> +++ b/contrib/virtiofsd/passthrough_ll.c
> @@ -2736,6 +2736,19 @@ static void setup_shared_versions(struct lo_data *lo)
>  	lo->version_table = addr;
>  }
>  
> +/*
> + * Called after our UNIX domain sockets have been created, now we can move to
> + * an empty network namespace to prevent TCP/IP and other network activity in
> + * case this process is compromised.
> + */
> +static void setup_net_namespace(void)
> +{
> +	if (unshare(CLONE_NEWNET) != 0) {
> +		fuse_log(FUSE_LOG_ERR, "unshare(CLONE_NEWNET): %m\n");
> +		exit(1);
> +	}
> +}
> +
>  /* This magic is based on lxc's lxc_pivot_root() */
>  static void setup_pivot_root(const char *source)
>  {
> @@ -2818,6 +2831,7 @@ static void setup_mount_namespace(const char *source)
>   */
>  static void setup_sandbox(struct lo_data *lo, bool enable_syslog)
>  {
> +	setup_net_namespace();
>  	setup_mount_namespace(lo->source);
>  	setup_seccomp(enable_syslog);
>  }
> -- 
> 2.21.0
> 
--
Dr. David Alan Gilbert / dgilbert at redhat.com / Manchester, UK