Author Archives: Giuseppe Paternò

About Giuseppe Paternò

Giuseppe Paternò a.k.a. Gippa is an IT Architect and Security Expert with background in Open Source. He works within the most famous italian and foreign companies in the telecommunications, government and finance industries. Since 2010 he’s the CTO and Director of GARL, a multinational company based in Switzerland and UK, under which he created SecurePass and SecureData. He also cooperates with key European companies as a trusted advisor. In the past he worked as Network and Security architect for Canonical, RedHat, Wind/Infostrada, Sun Microsystems and IBM and Visiting Researcher at the University of Dublin Trinity College. His writings, mainly on computer security, has inspired best practices and are referenced by companies and universities worldwide.

How to have a successful OpenStack project

It’s no secret that OpenStack is becoming the de-facto standard for private cloud and a way for telecom operators to differentiate against big names such as Amazon or Google.
OpenStack has already been adopted in some specific projects, but the wide adoption in enterprises is starting now, mostly because people simply find it difficult to understand. VMWare is still something to compare to, but OpenStack and cloud is different. While cloud implies virtualization, virtualization is not cloud.

gpaterno_ebook_webCloud is a huge shift in your organization and will change forever your way of working in the IT projects, improving your IT dramatically and cutting down costs.

In order to get the best of OpenStack, you need to understand deeply how cloud works. Moreover, you need to understand the whole picture beyond the software itself to provide new levels of agility, flexibility, and cost savings in your business.

Giuseppe Paterno’, leading European consultant and recently awarded by HP, wrote OpenStack Explained to guide you through the OpenStack technology and reveal his secret ingredient to have a successful project. You can download the ebook for a small donation to provide emergency and reconstruction aid for Nepal. Your donation is certified by ZEWO , the Swiss federal agency that ensures that funds go to a real charity project.

… but hurry up, the ebook is in a limited edition and it ends on July 2015.

Donate & Download here:

Handling identities in distributed Linux cloud instances

I’ve many distributed Linux instances across several clouds, be them global, such as Amazon or Digital Ocean, or regional clouds such as TeutoStack or Enter.

Probably many of you are facing the same issue: having a consistent UNIX identity across all multiple instances. While in an ideal world LDAP would be a perfect choice, letting LDAP open to the wild Internet is not a great idea.

So, how to solve this issue, while being secure? The trick is to use the new NSS module for SecurePass.

While SecurePass has been traditionally used into the operating system just as a two factor authentication, the new beta release is capable of holding “extended attributes”, i.e. arbitrary information for each user profile.

We will use SecurePass to authenticate users and store Unix information with this new capability. In detail, we will:

  • Use PAM to authenticate the user via RADIUS
  • Use the new NSS module for SecurePass to have a consistent UID/GID/….

 SecurePass and extended attributes

The next generation of SecurePass (currently in beta) is capable of storing arbitrary data for each profile. This is called “Extended Attributes” (or xattrs) and -as you can imagine- is organized as key/value pair.

You will need the SecurePass tools to be able to modify users’ extended attributes. The new releases of Debian Jessie and Ubuntu Vivid Vervet have a package for it, just:

# apt-get install securepass-tools

ERRATA CORRIGE: securepass-tools hasn’t been uploaded to Debian yet, Alessio is working hard to make the package available in time for Jessie though.

For other distributions or previous releases, there’s a python package (PIP) available. Make sure that you have pycurl installed and then:

# pip install securepass-tools

While SecurePass tools allow local configuration file, we highly recommend for this tutorial to create a global /etc/securepass.conf, so that it will be useful for the NSS module. The configuration file looks like:

app_id = xxxxx
app_secret = xxxx
endpoint =

Where app_id and app_secrets are valid API keys to access SecurePass beta.

Through the command line, we will be able to set UID, GID and all the required Unix attributes for each user:

# sp-user-xattrs set posixuid 1000

While posixuid is the bare minimum attribute to have a Unix login, the following attributes are valid:

  • posixuid → UID of the user
  • posixgid → GID of the user
  • posixhomedir → Home directory
  • posixshell → Desired shell
  • posixgecos → Gecos (defaults to username)

Install and Configure NSS SecurePass

In a similar way to the tools, Debian Jessie and Ubuntu Vivid Vervet have native package for SecurePass:

# apt-get install libnss-securepass

For previous releases of Debian and Ubuntu can still run the NSS module, as well as CentOS and RHEL. Download the sources from:


make install (Debian/Ubuntu Only)

For CentOS/RHEL/Fedora you will need to copy files in the right place:

/usr/bin/install -c -o root -g root /usr/lib64/
ln -sf /usr/lib64/

The /etc/securepass.conf configuration file should be extended to hold defaults for NSS by creating an [nss] section as follows:

realm =
default_gid = 100
default_home = "/home"
default_shell = "/bin/bash"

This will create defaults in case values other than posixuid are not being used. We need to configure the Name Service Switch (NSS) to use SecurePass. We will change the /etc/nsswitch.conf by adding “sp” to the passwd entry as follows:

$ grep sp /etc/nsswitch.conf
 passwd:     files sp

Double check that NSS is picking up our new SecurePass configuration by querying the passwd entries as follows:

$ getent passwd user
 user:x:1000:100:My User:/home/user:/bin/bash
$ id user
 uid=1000(user)  gid=100(users) groups=100(users)

Using this setup by itself wouldn’t allow users to login to a system because the password is missing. We will use SecurePass’ authentication to access the remote machine.

Configure PAM for SecurePass

On Debian/Ubuntu, install the RADIUS PAM module with:

# apt-get install libpam-radius-auth

If you are using CentOS or RHEL, you need to have the EPEL repository configured. In order to activate EPEL, follow the instructions on

Be aware that this has not being tested with SE-Linux enabled (check off or permissive).

On CentOS/RHEL, install the RADIUS PAM module with:

# yum -y install pam_radius

Note: as per the time of writing, EPEL 7 is still in beta and does not contain the Radius PAM module. A request has been filed through RedHat’s Bugzilla to include this package also in EPEL 7

Configure SecurePass with your RADIUS device. We only need to set the public IP Address of the server, a fully qualified domain name (FQDN), and the secret password for the radius authentication. In case of the server being under NAT, specify the public IP address that will be translated into it. After completion we get a small recap of the already created device. For the sake of example, we use “secret” as our secret password.

Configure the RADIUS PAM module accordingly, i.e. open /etc/pam_radius.conf and add the following lines: secret 3 secret 3

Of course the “secret” is the same we have set up on the SecurePass administration interface. Beyond this point we need to configure the PAM to correct manage the authentication.

In CentOS, open the configuration file /etc/pam.d/password-auth-ac; in Debian/Ubuntu open the /etc/pam.d/common-auth configuration and make sure that is in the list.

auth required
auth sufficient try_first_pass
auth sufficient nullok try_first_pass
auth requisite uid >= 500 quiet
auth required


Handling many distributed Linux poses several challenges, from software updates to identity management and central logging.  In a cloud scenario, it is not always applicable to use traditional enterprise solutions, but new tools might become very handy.

To freely subscribe to securepass beta, join SecurePass on:
And then send an e-mail to requesting beta access.