172 lines
6.8 KiB
Markdown
172 lines
6.8 KiB
Markdown
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---
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title: "Updating passwords with Ansible"
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date: 2019-01-19T00:00:00+01:00
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draft: false
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share: false
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---
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I've recently migrated from [KeePassXC](https://keepassxc.org/) to [Bitwarden_RS](https://github.com/dani-garcia/bitwarden_rs) (which I highly recommend, by the way) to manage my passwords.
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I figured it was an opportunity to update passwords I hadn't changed in... *years*. My Linux users' passwords were among those.
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Instead of updating them manually on each machine, I thought there might be a way to do so with Ansible, and since it turns out there is, I thought I might as well share it here!
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**Please be careful when it comes to password modification automation. You might end up locking yourself out of your servers.**
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## Generating password hashes
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First thing first, we'll need to generate `passwd` compatible password hashes for our users.
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In this example, I'll generate a hash for the *P@ssw0rd* password :
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```
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mkpasswd -m sha-512
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Password:
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$6$wAVPV.Coc$o3FNxs9EPgXF54hv1BeKtfoMnLwE5VATL71jlHQHeVyCaevnnxfSp/x1UbJ00F3qlyyfUAmscuGXImoHmXBFa.
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```
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You might notice you'll get a different result if you run the same command again :
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```
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mkpasswd -m sha-512
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Password:
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$6$iFBWJD3300m$CYZJRSfZ4scHYNI9ggqe8WYef7Qym2Oi5ycgb64VsbU3.WM1GoJYlh1sawENTD7nrXVCthvs8LRPw1CVjzkP71
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```
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That's because, unless you specify it, the salt used by `mkpasswd` to encrypt the password is random.
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You can choose a salt with the `-S` parameter if you want :
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```
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mkpasswd -m sha-512 -S hmmmsalt
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Password:
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$6$hmmmsalt$RwZR2r9W5cSv5bVgeSFPX0rJiovWOD5kMDFey1xPR6JtasqQZqHTiuW5JoQ.0VCW6oNHJlgOYJ.auhl82gfX8/
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mkpasswd -m sha-512 -S hmmmsalt
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Password:
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$6$hmmmsalt$RwZR2r9W5cSv5bVgeSFPX0rJiovWOD5kMDFey1xPR6JtasqQZqHTiuW5JoQ.0VCW6oNHJlgOYJ.auhl82gfX8/
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captainark@heimdall ~ %
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```
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## Ansible vault
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Passwords are *secrets*. Even if there are hashed, you don't want them to be publicly accessible.
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If, like me, your Ansible configuration is in a git repository, you should not commit them in an unencrypted file.
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Ansible offers a way to encrypt a file containing variables with the `ansible-vault` command.
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We first have to create a vault :
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```
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cd /your/ansible/project
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mkdir -p group_vars/all/
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ansible-vault create group_vars/all/vault.yml
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New Vault password:
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Confirm New Vault password:
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```
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As you can see, the command will ask you to provide a password for the vault. It will then open the file in your `$EDITOR` (that'll be `vim` if you're a cool kid).
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The file is like any Ansible vault file. I'll create a variable for the `root` and `captainark` users in my case :
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```yaml
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vault_captainarkpwd: "$6$hmmmsalt$RwZR2r9W5cSv5bVgeSFPX0rJiovWOD5kMDFey1xPR6JtasqQZqHTiuW5JoQ.0VCW6oNHJlgOYJ.auhl82gfX8/"
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vault_rootpwd: "$6$hmmmsalt$RwZR2r9W5cSv5bVgeSFPX0rJiovWOD5kMDFey1xPR6JtasqQZqHTiuW5JoQ.0VCW6oNHJlgOYJ.auhl82gfX8/"
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```
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An [Ansible best practice](https://docs.ansible.com/ansible/latest/user_guide/playbooks_best_practices.html#variables-and-vaults) is to prepend all variables that are stored in a vault with the `vault_` prefix. It makes where they are stored clear when reading through a playbook.
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Once saved, if you try to `cat` the file, you won't be able to see its actual content :
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```
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cat group_vars/all/vault.yml
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$ANSIBLE_VAULT;1.1;AES256
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32393530376537323233633636316330373136316265316662646437393533376135666232656366
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3335623863333865666133666634633233616531636634370a663965356466383039326262313066
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62633434396465313666333032663130343434326665386333323733633062613832653530393761
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6333653338393231640a623938616634626462653965613766313335386136333362313033363735
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64313662623039363365326639633231306335366432306361613837656364356464373837656565
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61636538376262333762376235306337303531386638643632316361323037393230366537393132
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35373861373863613666303531353737373130353330643535353238633665653236633130653064
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39346330326566633262613535386633613565633566623934613066613238353739386133346535
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64643762333462653966633363653439633037373161316663646261663764393332653732656335
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61373462666336343533333162663637656236333739633065623939323937663137376431346231
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38653338386539383663613230656165313566363733396134386366626430313235343264643938
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64306163353437366362616166666565316663366163346565313436343537366330363932303038
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37653138643165353138393466343063666535313933663066633832353331643838356539303533
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61626237356538353261326136613239336662346337363331393037623863623433336432353461
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32356136316339623139346330333235363331653634373836333730653436636563323134616337
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36643433356133376138
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```
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To view the variables in the file, you can use the `ansible-vault view` command :
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```yaml
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ansible-vault view group_vars/all/vault.yml
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Vault password:
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vault_captainarkpwd: "$6$hmmmsalt$RwZR2r9W5cSv5bVgeSFPX0rJiovWOD5kMDFey1xPR6JtasqQZqHTiuW5JoQ.0VCW6oNHJlgOYJ.auhl82gfX8/"
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vault_rootpwd: "$6$hmmmsalt$RwZR2r9W5cSv5bVgeSFPX0rJiovWOD5kMDFey1xPR6JtasqQZqHTiuW5JoQ.0VCW6oNHJlgOYJ.auhl82gfX8/"
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```
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To edit the vault's content, you can use the `ansible-vault edit group_vars/all/vault.yml` command.
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## The playbook
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Now that our vault is ready, all that's left is to run the following playbook :
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```yaml
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---
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- hosts: all
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become: yes
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become_method: sudo
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tasks:
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- name: PASSWORDS | Check if the captainark user exists
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shell: id -u captainark
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register: captainark_exists
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ignore_errors: true
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- name: PASSWORDS | Update captainark password
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user:
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name: captainark
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password: "{{ vault_captainarkpwd }}"
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update_password: always
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when: captainark_exists.rc == 0
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- name: PASSWORDS | Create captainark user
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user:
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name: captainark
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password: "{{ vault_captainarkpwd }}"
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shell: /usr/bin/zsh
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uid: 1000
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groups: adm,sudo,apps
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when: captainark_exists.rc != 0
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- name: PASSWORDS | Update root password
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user:
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name: root
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password: "{{ vault_rootpwd }}"
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update_password: always
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```
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I've called this playbook `passwords.yml`. To run it, I simply execute the following command :
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```
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ansible-playbook passwords.yml --ask-vault-pass
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```
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The command asks for the vault password to decrypt its contents.
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The playbook will first check if the `captainark` user exists, and it will update its password if it does. If it doesn't, the user will be created with the defined options.
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Since the `root` user should always exist, the playbook changes its password without checking.
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**N.B. :** If you've decided to store your vault somewhere else, you might need to add a task at the beginning of the playbook to load it, like so :
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```yaml
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- name: PASSWORDS | Load the vault
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include_vars: /path/to/your/vault.yml
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```
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## Conclusion
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That's all! As always, I hope someone finds this article useful!
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If you do, please let me know in the comments here, on [Twitter](https://twitter.com/captainark) or on the [Fediverse](https://social.captainark.net/users/captainark/)!
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Also, if you have any questions, feel free to hit me up on my [Rocket.Chat](https://chat.captainark.net) instance! Hopefully I'll write about it in the future!
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