[lxc-devel] FW: [PATCH] Add Dropbear SSH support for lxc-busybox template

[Dwight Engen]

On Mon, 14 Jan 2013 09:37:05 -0500
Stéphane Graber <stgraber at ubuntu.com> wrote:

> Forwarding this from Bogdan as for some weird reason his e-mails are
> put in the mailing-list moderation queue (even though he's
> subscribed).
> 
> Personally I think this change is good and would make the busybox
> template behave similarly than the others where SSH is usually
> automatically enabled.
> 
> But I'm not actually using that template so I'd prefer if someone
> actually using it could give their opinion on whether they're fine
> with this behaviour by default or would rather have it moved behind a
> command line option to the template.

I only use it when I want to test something quickly in a very light
system container. Since it checks for dropbear availability (see below
for type vs which), I think it shouldn't break anything.

> -----Original Message-----
> From: Purcareata Bogdan-B43198 Sent: Monday, January 14, 2013 11:51 AM
> To: 'lxc-users at lists.sourceforge.net'
> Subject: FW: [PATCH] Add Dropbear SSH support for lxc-busybox template
> 
> Hello,
> 
> I've sent this patch to lxc-devel and received a notification of
> pending for approval from a maintainer. Since I didn't receive any
> answer yet, I was not sure it was the right place.
> 
> Bogdan P.
> 
> 
> -----Original Message-----
> From: Purcareata Bogdan-B43198 Sent: Thursday, January 10, 2013 2:23
> PM To: 'lxc-devel at lists.sourceforge.net'
> Subject: [PATCH] Add Dropbear SSH support for lxc-busybox template
> 
> Dropbear implements lightweight SSH2 server and client functionality
> and is likely to be included in embedded Linux distros.
> 
> Patch is done against staging branch.
> 
> Bogdan P.
> 
> diff --git a/templates/lxc-busybox.in b/templates/lxc-busybox.in index
> f2751d8..014aac4 100644
> --- a/templates/lxc-busybox.in
> +++ b/templates/lxc-busybox.in
> @@ -33,7 +33,9 @@ $rootfs/root \
>  $rootfs/etc \
>  $rootfs/etc/init.d \
>  $rootfs/bin \
> +$rootfs/usr/bin \
>  $rootfs/sbin \
> +$rootfs/usr/sbin \
>  $rootfs/proc \
>  $rootfs/mnt \
>  $rootfs/tmp \
> @@ -63,6 +65,8 @@ $rootfs/usr/lib64"
>      chmod 600 ram0        || res=1
>      mknod null c 1 3      || res=1
>      chmod 666 null        || res=1
> +    mknod urandom c 1 9   || res=1
> +    chmod 666 urandom     || res=1
> 
>      popd > /dev/null
> 
> @@ -188,6 +192,36 @@ configure_busybox()
>      echo "setting root passwd to root"
>      echo "root:root" | chroot $rootfs chpasswd
> 
> +
> +    # add ssh functionality if dropbear package available on host
> +    type dropbear >/dev/null

nit: I think we should use which instead of type here since which is
what is used below, and type might include shell functions/builtin's
that we don't want here.

> +    if [ $? -eq 0 ]; then
> +        # copy dropbear binary
> +        cp $(which dropbear) $rootfs/usr/sbin
> +        if [ $? -ne 0 ]; then
> +            echo "Failed to copy dropbear in the rootfs"
> +            return 1
> +        fi
> +
> +        # make symlinks to various ssh utilities
> +        utils="\
> +            $rootfs/usr/bin/dbclient \
> +            $rootfs/usr/bin/scp \
> +            $rootfs/usr/bin/ssh \
> +            $rootfs/usr/sbin/dropbearkey \
> +            $rootfs/usr/sbin/dropbearconvert \
> +        "
> +        echo $utils | xargs -n1 ln -s /usr/sbin/dropbear
> +
> +        # add necessary config files
> +        mkdir $rootfs/etc/dropbear
> +        dropbearkey -t rsa -f
> $rootfs/etc/dropbear/dropbear_rsa_host_key &> /dev/null
> +        dropbearkey -t dss -f +
> $rootfs/etc/dropbear/dropbear_dss_host_key &> /dev/null
> +
> +        echo "'dropbear' ssh utility installed"
> +    fi
> +
>      return 0
>  }
> 
>