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Latest Posts
- Log into a Docker Container as root Posted on October 28, 2018
- Homelab Updates! Posted on October 12, 2018
- Annoying Ansible Gotcha Posted on April 14, 2018
- Working with Ruby obfuscated code: Finding all classes available in a module Posted on May 24, 2017
- aws cli AuthFailure gotcha Posted on January 30, 2017
October 28, 2018
Log into a Docker Container as root
by Alpha01
docker exec -u 0 -it mycontainer bash
docker security October 12, 2018
Homelab Updates!
by Alpha01
It’s been well over a month since I finally decided to retire both of my Apple Mac Minis in favor for a single (for the time being), quieter, and more powerful Intel NUC.
Migrating over my existing KVM and VirtualBox VMs to my new KVM server was a really easy process. If doing the import manually, then it’s just a matter of selecting the existing vdi and qcow2 images as the source disks when creating the guests VMs on the server. In my cause, however I also had to update the new MAC address given that all of my VMs are configured to get their respective fixed IP addresses via my isc-dhcpd server.
This this was somewhat of a fresh start, so I nuked a bunch of unused VMs that I had lingering around for testing purposes, and only kept what I really need for now. Which at the time of this writing these are my current active VMs that I use on my homelab:
proxy- Reverse proxy Varnish and Nginx (SSL termination)dhcp- ISC-dhcpd and PXE serverdatabase- MySQL and PostgreSQL servermonitor- Nagios, Graphite/Grafanaweb- Apachens1- Master BIND serverns2- Slave BIND servergit- GitLab and Subversionansible- Ansible and Puppet Configuration Managementbuild- Jenkinslogs- ELK stack
Future Plans
I have lots of future plans for my homelab. Like upgrading my BIND DNS servers to a new version and rollout out DNSSec on my local network, upgrading dhcp server (running a really old version of Debian), rollout 389 Directory Server (I have a love/hate relationship with openldap). These are just to name a few!
Tags: [ubuntu kvm April 14, 2018
Annoying Ansible Gotcha
by Alpha01
Ansible is by far my favorite Configuration Management tool, however it certainly has it’s own unique quirks and annoyances. To start, I prefer the Ansible’s YAML/Jinja approach instead of Puppet and Chef’s own DSL custom configurations.
Today I ran into an interesting YAML parsing quirk. It turns out if you use colon ‘:’ character inside a string anywhere in your playbooks, Ansible will fail to properly parse it.
Example playbook:
---
- hosts: 127.0.0.1
tasks:
- lineinfile: dest=/etc/sudoers regexp='^testuser ALL=' state=present line="testuser ALL=(ALL) NOPASSWD: TEST_PROGRAM" state=present
Error
When running the playbook, triggers the following error:
ERROR! Syntax Error while loading YAML.
The error appears to have been in '/etc/ansible/one_off_playbooks/example.yml': line 4, column 104, but may
be elsewhere in the file depending on the exact syntax problem.
The offending line appears to be:
tasks:
- lineinfile: dest=/etc/sudoers regexp='^testuser ALL=' state=present line="testuser ALL=(ALL) NOPASSWD: TEST_PROGRAM" state=present
^ here
Fix
This is a known issue https://github.com/ansible/ansible/issues/1341 and the easiest work around for this, is to force the colon ‘:’ character to be evaluated by the Jinja templating engine.
{{':'}}
The hilarious part of this, is that it doesn’t look like this stupid quirk is going to be fixed.
Tags: [ansible May 24, 2017
Working with Ruby obfuscated code: Finding all classes available in a module
by Alpha01
As a follow up to my HashiCorp Rocks! blog post. Up until now, I’ve never directly worked with any obfuscated code. HashiCorp obfuscates their VMware Fusion and Workstation commercial Vagrant plugins.
Like Vagrant, the plugins themselves are written in Ruby.
alpha03:lib tony$ file vagrant-vmware-fusion.rb
vagrant-vmware-fusion.rb: ASCII text, with very long lines, with CRLF, LF line terminators
However, if you try to read the source all you’ll see is a bunch of encoded text. Since my Vagrant plugin has some functionality that only works after a certain action gets executed by the proprietary plugins. This is why I needed to know the exact name of that particular action (class name) exactly how it’s defined inside the VMware Fusion and Workstation plugins. This was a serious problem because I can’t read their source code!
Luckily, this wasn’t as difficult as it seems. Finding the classes (or methods but in the case of mine I didn’t need too) available in Ruby is fairly simple process. To my luck somebody had already asked and answered this question in StackOverflow.
In my case, first step was needing to know the name of the actual module itself. I found the easiest way to get the name of the module that’s obfuscated, is to intentionally have it spit out an exception. In doing that, I found that the module names whose namespace I’ll be searching were HashiCorp::VagrantVMwarefusion and HashiCorp::VagrantVMwareworkstation.
Once I knew the modules’s name, I was able to use Ruby to view what additional modules I have within the particular module namespace. I was able to accomplish that using the following
t = HashiCorp::VagrantVMwareworkstation.constants.select {|c|
HashiCorp::VagrantVMwareworkstation.const_get(c).is_a? Module
}
puts t
The above sample code spit out a bunch of modules inside HashiCorp::VagrantVMwareworkstation, but since I know the Vagrant plugin API and it’s coding standards/practices. I was able to verify that the module I’m searching for is HashiCorp::VagrantVMwareworkstation::Action. Once again, looking at Plugin API and other examples, I knew that this is where the class is I’m looking is stored in. So I used the following to get the corresponding class name within HashiCorp::VagrantVMwareworkstation::Action.
p = HashiCorp::VagrantVMwareworkstation::Action.constants.select { |c|
HashiCorp::VagrantVMwareworkstation::Action.const_get(c).is_a? Class
}
puts p
I repeated the above tests for HashiCorp::VagrantVMwarefusion and I was also able to find the corresponding class name that it’s defined inside the obfuscated Ruby code.
In the end I was able to get the classes HashiCorp::VagrantVMwareworkstation::Action::Suspend and HashiCorp::VagrantVMwarefusion::Action::Suspend, and everything worked as expected.
Tags: [ruby vagrant January 30, 2017
aws cli AuthFailure gotcha
by Alpha01
It’s probably been about 5-6 years since the last time I’ve used the AWS command line tools. The other day I signed up for the AWS Free Tier to familiarize myself with the aws command-line tools once again. I created myself a test user and granted full access to my aws account. Easy and simple. Well not so fast, initially my user account failed to authenticate properly. I tried re-generating new API keys and even created other different accounts with different types of access, but the problem persisted.
Problem
I was getting the following error:
[root@bashninja ~]# aws ec2 describe-regions
An error occurred (AuthFailure) when calling the DescribeRegions operation: AWS was not able to validate the provided access credentials
I verified my AWS API credentials stored on ~/.aws/credentials to ensure everything was correct. Yet, the fucking problem persisted.
Fix
It turned out that the time on the system I was trying to use the aws cli tools in, had the time completely wrong! Once the time was fixed I was able to authenticate my account and use the aws cli tool.
Tags: [aws python