From kzar79 at gmail.com  Sun Feb  3 13:25:14 2013
From: kzar79 at gmail.com (Cesare Bianchi)
Date: Sun, 03 Feb 2013 13:25:14 +0100
Subject: Http server instead of own server?
Message-ID: <510E572A.2080601@gmail.com>

Dear all,

I have the following situation:

I manage various (virtual) servers running in various clients' 
locations. The clients must not have direct access to the servers data, 
so I ecnrypted the disks. At the present time, I must physically go (or 
connect to the virtual host) if a server reboots.

I wanted to install Mandos client on the servers, but it needs a Mandos 
server runnning in the network, and obviously this only adds complexity.

So, is it possible to use some simple form of connection to the "Mandos 
server", for example with a public basic http server?

I didn't study the Mandos handshake process, but I think that any php 
page could decrypt with a public key a random generated string, and then 
use that string to encrypt the password and send it as reply (which is 
essentially the ssl handshake). Obviously this means that the http 
server must be secured and available, but it's not a great problem, I think.

Probably the greatest problem would be for the "client" to have the 
interface configured with the gateway and nameserver, during the boot.

Do you think it is complex to modify the Mandos client (or write another 
plugin) to do so? Would you point me in the right direction, so I could 
possibly do it?

Thank you in advance,

Cesare

From teddy at recompile.se  Wed Feb 13 12:27:12 2013
From: teddy at recompile.se (Teddy Hogeborn)
Date: Wed, 13 Feb 2013 12:27:12 +0100
Subject: Http server instead of own server?
In-Reply-To: <510E572A.2080601@gmail.com> (Cesare Bianchi's message of "Sun,
	03 Feb 2013 13:25:14 +0100")
References: <510E572A.2080601@gmail.com>
Message-ID: <87mwv88ne7.fsf@tower.recompile.se>

Cesare Bianchi <kzar79 at gmail.com> writes:

> I manage various (virtual) servers running in various clients'
> locations. The clients must not have direct access to the servers
> data, so I ecnrypted the disks. At the present time, I must physically
> go (or connect to the virtual host) if a server reboots.
>
> I wanted to install Mandos client on the servers, but it needs a
> Mandos server runnning in the network, and obviously this only adds
> complexity.
>
> So, is it possible to use some simple form of connection to the
> "Mandos server", for example with a public basic http server?

Firstly, your setup is not secure.  Your clients can access the memory
of the virtual machines, where the keys to the encrypted disks are
stored.

Secondly, the problem you want to solve does not need any source
changes; the code is written to be flexible enough to cover your use
case.  What you should do is four things:

1. Add "ip=dhcp" to the Linux kernel command line; do this by editing
   the GRUB_CMDLINE_LINUX_DEFAULT setting in your /etc/default/grub
   file; add "ip=dhcp" to the setting.  If DHCP is not available for the
   Mandos client systems, use the syntax "ip=1.1.1.2::1.1.1.1", where
   "1.1.1.2" is the client IP address and "1.1.1.1" is the local
   gateway.

2. Add, to the /etc/mandos/plugin-runner.conf file, this line:

--options-for=mandos-client:--connect=1.2.3.4:1234

   Replace "1.2.3.4:1234" with the IP address and your chosen port of
   the Mandos server.
   
3. Run "update-initramfs -k all -u" to update the initramfs image.

4. Configure the Mandos server to use a specific port number by
   uncommenting and editing the "port" setting in /etc/mandos.conf on
   the Mandos server host.

(Note; I have written these four steps mostly from my memory of how this
is supposed to work, but I have not tested them.  It is always possible
I have forgotten something.)

/Teddy Hogeborn

-- 
The Mandos Project
http://www.recompile.se/mandos

From garbytrash at gmail.com  Wed Feb 13 12:37:09 2013
From: garbytrash at gmail.com (Zenny)
Date: Wed, 13 Feb 2013 12:37:09 +0100
Subject: Http server instead of own server?
In-Reply-To: <87mwv88ne7.fsf@tower.recompile.se>
References: <510E572A.2080601@gmail.com>
	<87mwv88ne7.fsf@tower.recompile.se>
Message-ID: <CACuV5sBAhhjko6QYbGoHKNqKR5pi+1MAUNbUGMMLPGk_YTt0JA@mail.gmail.com>

On 2/13/13, Teddy Hogeborn <teddy at recompile.se> wrote:
> Cesare Bianchi <kzar79 at gmail.com> writes:
>
>> I manage various (virtual) servers running in various clients'
>> locations. The clients must not have direct access to the servers
>> data, so I ecnrypted the disks. At the present time, I must physically
>> go (or connect to the virtual host) if a server reboots.
>>
>> I wanted to install Mandos client on the servers, but it needs a
>> Mandos server runnning in the network, and obviously this only adds
>> complexity.
>>
>> So, is it possible to use some simple form of connection to the
>> "Mandos server", for example with a public basic http server?
>
> Firstly, your setup is not secure.  Your clients can access the memory
> of the virtual machines, where the keys to the encrypted disks are
> stored.
>
> Secondly, the problem you want to solve does not need any source
> changes; the code is written to be flexible enough to cover your use
> case.  What you should do is four things:
>
> 1. Add "ip=dhcp" to the Linux kernel command line; do this by editing
>    the GRUB_CMDLINE_LINUX_DEFAULT setting in your /etc/default/grub
>    file; add "ip=dhcp" to the setting.  If DHCP is not available for the
>    Mandos client systems, use the syntax "ip=1.1.1.2::1.1.1.1", where
>    "1.1.1.2" is the client IP address and "1.1.1.1" is the local
>    gateway.
>
> 2. Add, to the /etc/mandos/plugin-runner.conf file, this line:
>
> --options-for=mandos-client:--connect=1.2.3.4:1234
>
>    Replace "1.2.3.4:1234" with the IP address and your chosen port of
>    the Mandos server.

Thanks Teddy for sharing very useful info, that I have been searching
for. Great!

BTW, it is a bit confusing for me at least. You stated that replace
the IP with the Mandos Server IP, and I guess the change to the
/etc/mandos/plugin-runner.conf  is needed to be made in the Mandos
client machine right?

>
> 3. Run "update-initramfs -k all -u" to update the initramfs image.
>
> 4. Configure the Mandos server to use a specific port number by
>    uncommenting and editing the "port" setting in /etc/mandos.conf on
>    the Mandos server host.
>
> (Note; I have written these four steps mostly from my memory of how this
> is supposed to work, but I have not tested them.  It is always possible
> I have forgotten something.)
>
> /Teddy Hogeborn
>
> --
> The Mandos Project
> http://www.recompile.se/mandos
> _______________________________________________
> Mandos-Dev mailing list
> Mandos-Dev at recompile.se
> https://mail.recompile.se/cgi-bin/mailman/listinfo/mandos-dev
>

From teddy at recompile.se  Sat Feb 16 02:25:31 2013
From: teddy at recompile.se (Teddy Hogeborn)
Date: Sat, 16 Feb 2013 02:25:31 +0100
Subject: Http server instead of own server?
In-Reply-To: <CACuV5sBAhhjko6QYbGoHKNqKR5pi+1MAUNbUGMMLPGk_YTt0JA@mail.gmail.com>
	(Zenny's message of "Wed, 13 Feb 2013 12:37:09 +0100")
References: <510E572A.2080601@gmail.com> <87mwv88ne7.fsf@tower.recompile.se>
	<CACuV5sBAhhjko6QYbGoHKNqKR5pi+1MAUNbUGMMLPGk_YTt0JA@mail.gmail.com>
Message-ID: <87k3q9yrqs.fsf@tower.recompile.se>

Zenny <garbytrash at gmail.com> writes:

> > > So, is it possible to use some simple form of connection to the
> > > "Mandos server", for example with a public basic http server?
> >
[...]
> >
> > 1. Add "ip=dhcp" to the Linux kernel command line; do this by
> >    editing the GRUB_CMDLINE_LINUX_DEFAULT setting in your
> >    /etc/default/grub file; add "ip=dhcp" to the setting.  If DHCP is
> >    not available for the Mandos client systems, use the syntax
> >    "ip=1.1.1.2::1.1.1.1", where "1.1.1.2" is the client IP address
> >    and "1.1.1.1" is the local gateway.
> >
> > 2. Add, to the /etc/mandos/plugin-runner.conf file, this line:
> >
> > --options-for=mandos-client:--connect=1.2.3.4:1234
> >
> >    Replace "1.2.3.4:1234" with the IP address and your chosen port of
> >    the Mandos server.
>
> Thanks Teddy for sharing very useful info, that I have been searching
> for. Great!
>
> BTW, it is a bit confusing for me at least. You stated that replace
> the IP with the Mandos Server IP, and I guess the change to the
> /etc/mandos/plugin-runner.conf is needed to be made in the Mandos
> client machine right?

Steps 1 through 3 is on the Mandos client; step 4 is on the Mandos
server.  Sorry; I should have clarified.

> > 3. Run "update-initramfs -k all -u" to update the initramfs image.
> >
> > 4. Configure the Mandos server to use a specific port number by
> >    uncommenting and editing the "port" setting in /etc/mandos.conf
> >    on the Mandos server host.

/Teddy Hogeborn

-- 
The Mandos Project
http://www.recompile.se/mandos

From garbytrash at gmail.com  Sat Feb 16 13:06:57 2013
From: garbytrash at gmail.com (Zenny)
Date: Sat, 16 Feb 2013 13:06:57 +0100
Subject: Http server instead of own server?
In-Reply-To: <87k3q9yrqs.fsf@tower.recompile.se>
References: <510E572A.2080601@gmail.com> <87mwv88ne7.fsf@tower.recompile.se>
	<CACuV5sBAhhjko6QYbGoHKNqKR5pi+1MAUNbUGMMLPGk_YTt0JA@mail.gmail.com>
	<87k3q9yrqs.fsf@tower.recompile.se>
Message-ID: <CACuV5sAG0KW_F1eVsJ3UfZEe+Ai=QuHFb=v_4p8GU8UwsCHc0A@mail.gmail.com>

Teddy, thanks for clarification.

But in the meantime, how secure is TLS authentication of remote mandos
client-server authentication against the exploits discovered recently
like the one at http://www.isg.rhul.ac.uk/tls/, and the /. discussion
at http://it.slashdot.org/story/13/02/06/2337228/researchers-devise-new-attack-techniques-against-ssl
and at http://tech.slashdot.org/story/11/09/20/1833232/hackers-break-browser-ssltls-encryption?

Just eager to know how mandos server-client architecture prevents such
vulnerabilities?! Thanks again.

On 2/16/13, Teddy Hogeborn <teddy at recompile.se> wrote:
> Zenny <garbytrash at gmail.com> writes:
>
>> > > So, is it possible to use some simple form of connection to the
>> > > "Mandos server", for example with a public basic http server?
>> >
> [...]
>> >
>> > 1. Add "ip=dhcp" to the Linux kernel command line; do this by
>> >    editing the GRUB_CMDLINE_LINUX_DEFAULT setting in your
>> >    /etc/default/grub file; add "ip=dhcp" to the setting.  If DHCP is
>> >    not available for the Mandos client systems, use the syntax
>> >    "ip=1.1.1.2::1.1.1.1", where "1.1.1.2" is the client IP address
>> >    and "1.1.1.1" is the local gateway.
>> >
>> > 2. Add, to the /etc/mandos/plugin-runner.conf file, this line:
>> >
>> > --options-for=mandos-client:--connect=1.2.3.4:1234
>> >
>> >    Replace "1.2.3.4:1234" with the IP address and your chosen port of
>> >    the Mandos server.
>>
>> Thanks Teddy for sharing very useful info, that I have been searching
>> for. Great!
>>
>> BTW, it is a bit confusing for me at least. You stated that replace
>> the IP with the Mandos Server IP, and I guess the change to the
>> /etc/mandos/plugin-runner.conf is needed to be made in the Mandos
>> client machine right?
>
> Steps 1 through 3 is on the Mandos client; step 4 is on the Mandos
> server.  Sorry; I should have clarified.
>
>> > 3. Run "update-initramfs -k all -u" to update the initramfs image.
>> >
>> > 4. Configure the Mandos server to use a specific port number by
>> >    uncommenting and editing the "port" setting in /etc/mandos.conf
>> >    on the Mandos server host.
>
> /Teddy Hogeborn
>
> --
> The Mandos Project
> http://www.recompile.se/mandos
> _______________________________________________
> Mandos-Dev mailing list
> Mandos-Dev at recompile.se
> https://mail.recompile.se/cgi-bin/mailman/listinfo/mandos-dev
>

From cesare at cesarebianchi.com  Sun Feb 17 21:23:03 2013
From: cesare at cesarebianchi.com (Cesare Bianchi)
Date: Sun, 17 Feb 2013 21:23:03 +0100
Subject: Http server instead of own server?
In-Reply-To: <511BA245.7030805@gmail.com>
References: <511BA245.7030805@gmail.com>
Message-ID: <51213C27.60801@cesarebianchi.com>

Thank you for your suggestions.

I have been thinking about the security of my proposed solution, and I
realized that there are many loopholes.

Anyway, the solution you propose needs a mandos server running on some
machine, and a static ip address. What I propose is to replace the
mandos server with a public http server (possibly LAMP, possibly with
virtual hosts).
1. The client uses a normal http get request sending a random generated
(simmetric) key encrypted with its private key;
(e.g. http://www.mymandos.com/pass.php?k=asdfghjqwetyuio).
2. The http server decrypts the random key with the client's public key,
then encrypts the luks key with the random key, and sends it back in the
response;
3. The client decrypts the luks key with the random key, and uses it to
unlock the disk.

The luks key exists in clear only for some microseconds.

Anyway, if somebody gets the initramfs of the computer, can easily run
the mandos client from the command line, which would connect to the
server, get the luks key and give it in clear to the user. Bye bye privacy.

This is a problem inherent to the mandos system. I mean, anybody can get
the luks key using the mandos client from command line, if the client
can connect to the mandos server.
Obviously, if both the mandos server and client are controlled by you,
you can turn off the mandos server when somebody "steals" the client.

I was also thinking of adding in the request some hash of something
inherent to the initramfs, so if somebody "disassembles" the initramfs,
the request made from command line would have a different hash, and the
http server would give a different response (or no response at all). But
the problem of the open source code is that the algoirthm is public, so
the user could easily discover what is the "magic hash" and compute it
for itself. Back to square 1.

Probably I will use a much easier solution. An ssh daemon running in the
initramfs, and an automatic connection to an openvpn server (or if I
discover how, to a hamachi network). So at least I can decide if and
when issue the luks key, connecting with ssh.

Obviously, the user could make a sandbox with the initramfs and make me
think I am giving the luks key to the real machine, while I am giving it
to him, but with such a user, better give him directly the luks key!

Hope that my reflections can be useful to other people, and thank you
anyway,

Cesare



Il 13/02/2013 12:27, Teddy Hogeborn ha scritto:
> Cesare Bianchi <kzar79 at gmail.com> writes:
>
>> I manage various (virtual) servers running in various clients'
>> locations. The clients must not have direct access to the servers
>> data, so I ecnrypted the disks. At the present time, I must physically
>> go (or connect to the virtual host) if a server reboots.
>>
>> I wanted to install Mandos client on the servers, but it needs a
>> Mandos server runnning in the network, and obviously this only adds
>> complexity.
>>
>> So, is it possible to use some simple form of connection to the
>> "Mandos server", for example with a public basic http server?
>
> Firstly, your setup is not secure.  Your clients can access the memory
> of the virtual machines, where the keys to the encrypted disks are
> stored.
>
> Secondly, the problem you want to solve does not need any source
> changes; the code is written to be flexible enough to cover your use
> case.  What you should do is four things:
>
> 1. Add "ip=dhcp" to the Linux kernel command line; do this by editing
>     the GRUB_CMDLINE_LINUX_DEFAULT setting in your /etc/default/grub
>     file; add "ip=dhcp" to the setting.  If DHCP is not available for the
>     Mandos client systems, use the syntax "ip=1.1.1.2::1.1.1.1", where
>     "1.1.1.2" is the client IP address and "1.1.1.1" is the local
>     gateway.
>
> 2. Add, to the /etc/mandos/plugin-runner.conf file, this line:
>
> --options-for=mandos-client:--connect=1.2.3.4:1234
>
>     Replace "1.2.3.4:1234" with the IP address and your chosen port of
>     the Mandos server.
>
> 3. Run "update-initramfs -k all -u" to update the initramfs image.
>
> 4. Configure the Mandos server to use a specific port number by
>     uncommenting and editing the "port" setting in /etc/mandos.conf on
>     the Mandos server host.
>
> (Note; I have written these four steps mostly from my memory of how this
> is supposed to work, but I have not tested them.  It is always possible
> I have forgotten something.)
>
> /Teddy Hogeborn
>



From garbytrash at gmail.com  Mon Feb 18 08:09:06 2013
From: garbytrash at gmail.com (Zenny)
Date: Mon, 18 Feb 2013 07:09:06 +0000
Subject: Http server instead of own server?
In-Reply-To: <51213C27.60801@cesarebianchi.com>
References: <511BA245.7030805@gmail.com>
	<51213C27.60801@cesarebianchi.com>
Message-ID: <CACuV5sAf54vs6nmU3+v5LeW8T_rzY0k+11cBSeFkFuTosJ9kkQ@mail.gmail.com>

On Sun, Feb 17, 2013 at 8:23 PM, Cesare Bianchi <cesare at cesarebianchi.com>wrote:

> Thank you for your suggestions.
>
> I have been thinking about the security of my proposed solution, and I
> realized that there are many loopholes.
>
> Anyway, the solution you propose needs a mandos server running on some
> machine, and a static ip address. What I propose is to replace the
> mandos server with a public http server (possibly LAMP, possibly with
> virtual hosts).
> 1. The client uses a normal http get request sending a random generated
> (simmetric) key encrypted with its private key;
> (e.g. http://www.mymandos.com/pass.**php?k=asdfghjqwetyuio<http://www.mymandos.com/pass.php?k=asdfghjqwetyuio>
> ).
> 2. The http server decrypts the random key with the client's public key,
> then encrypts the luks key with the random key, and sends it back in the
> response;
> 3. The client decrypts the luks key with the random key, and uses it to
> unlock the disk.
>
> The luks key exists in clear only for some microseconds.
>
> Anyway, if somebody gets the initramfs of the computer, can easily run
> the mandos client from the command line, which would connect to the
> server, get the luks key and give it in clear to the user. Bye bye privacy.
>
> This is a problem inherent to the mandos system. I mean, anybody can get
> the luks key using the mandos client from command line, if the client
> can connect to the mandos server.
> Obviously, if both the mandos server and client are controlled by you,
> you can turn off the mandos server when somebody "steals" the client.
>
> I was also thinking of adding in the request some hash of something
> inherent to the initramfs, so if somebody "disassembles" the initramfs,
> the request made from command line would have a different hash, and the
> http server would give a different response (or no response at all). But
> the problem of the open source code is that the algoirthm is public, so
> the user could easily discover what is the "magic hash" and compute it
> for itself. Back to square 1.
>
> Probably I will use a much easier solution. An ssh daemon running in the
> initramfs, and an automatic connection to an openvpn server (or if I
> discover how, to a hamachi network). So at least I can decide if and
> when issue the luks key, connecting with ssh.
>

Thanks for sharing your thoughts.

In view of the TLS/SSL vulnerabilities still unresolved, this seems to be
the best option for now to embed dropbear in initramfs and then make an
automatic connection to an openvpn server, but the kind of remote control
that mandos client-server provides gets missing in this setup.


>
> Obviously, the user could make a sandbox with the initramfs and make me
> think I am giving the luks key to the real machine, while I am giving it
> to him, but with such a user, better give him directly the luks key!
>
> Hope that my reflections can be useful to other people, and thank you
> anyway,
>
> Cesare
>
>
>
> Il 13/02/2013 12:27, Teddy Hogeborn ha scritto:
>
>> Cesare Bianchi <kzar79 at gmail.com> writes:
>>
>>  I manage various (virtual) servers running in various clients'
>>> locations. The clients must not have direct access to the servers
>>> data, so I ecnrypted the disks. At the present time, I must physically
>>> go (or connect to the virtual host) if a server reboots.
>>>
>>> I wanted to install Mandos client on the servers, but it needs a
>>> Mandos server runnning in the network, and obviously this only adds
>>> complexity.
>>>
>>> So, is it possible to use some simple form of connection to the
>>> "Mandos server", for example with a public basic http server?
>>>
>>
>> Firstly, your setup is not secure.  Your clients can access the memory
>> of the virtual machines, where the keys to the encrypted disks are
>> stored.
>>
>> Secondly, the problem you want to solve does not need any source
>> changes; the code is written to be flexible enough to cover your use
>> case.  What you should do is four things:
>>
>> 1. Add "ip=dhcp" to the Linux kernel command line; do this by editing
>>     the GRUB_CMDLINE_LINUX_DEFAULT setting in your /etc/default/grub
>>     file; add "ip=dhcp" to the setting.  If DHCP is not available for the
>>     Mandos client systems, use the syntax "ip=1.1.1.2::1.1.1.1", where
>>     "1.1.1.2" is the client IP address and "1.1.1.1" is the local
>>     gateway.
>>
>> 2. Add, to the /etc/mandos/plugin-runner.conf file, this line:
>>
>> --options-for=mandos-client:--**connect=1.2.3.4:1234
>>
>>     Replace "1.2.3.4:1234" with the IP address and your chosen port of
>>     the Mandos server.
>>
>> 3. Run "update-initramfs -k all -u" to update the initramfs image.
>>
>> 4. Configure the Mandos server to use a specific port number by
>>     uncommenting and editing the "port" setting in /etc/mandos.conf on
>>     the Mandos server host.
>>
>> (Note; I have written these four steps mostly from my memory of how this
>> is supposed to work, but I have not tested them.  It is always possible
>> I have forgotten something.)
>>
>> /Teddy Hogeborn
>>
>>
>
> ______________________________**_________________
> Mandos-Dev mailing list
> Mandos-Dev at recompile.se
> https://mail.recompile.se/cgi-**bin/mailman/listinfo/mandos-**dev<https://mail.recompile.se/cgi-bin/mailman/listinfo/mandos-dev>
>
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