GNU/Linux

How to convert certificate of Let’s encrypt to jks

 in GNU/Linux  tagged certificate / encryption / jks / Let's Encrypt / p12 / PKCS#12 by

To convert a Let’s Encrypt SSL certificate (issued as PEM files) into a Java Keystore (JKS), follow these steps:

Step-by-step guide:

Step 1: Get the files ready

After obtaining your certificate from Let’s Encrypt, you’ll typically have the following files:

  • cert.pem (your domain certificate)
  • privkey.pem (private key)
  • chain.pem (CA intermediate certificates)
  • fullchain.pem (combined certificate with intermediate)

Ensure these files are available on your machine.

Step 2: Combine your certificate and private key into PKCS12 format

Use OpenSSL to create a PKCS12 (.p12) file:

openssl pkcs12 -export \
  -in fullchain.pem \
  -inkey privkey.pem \
  -out certificate.p12 \
  -name your_alias

Replace your_alias with a meaningful alias, such as your domain name.

You’ll be asked to set a password. Remember this password, as you’ll need it to import into the keystore.

Step 3: Import PKCS12 file into JKS Keystore

Now, convert the PKCS12 file (certificate.p12) into a JKS keystore:

keytool -importkeystore \
  -deststorepass YOUR_KEYSTORE_PASSWORD \
  -destkeypass YOUR_KEYSTORE_PASSWORD \
  -destkeystore keystore.jks \
  -srckeystore certificate.p12 \
  -srcstoretype PKCS12 \
  -srcstorepass YOUR_PKCS12_PASSWORD \
  -alias your_alias
  • Replace YOUR_KEYSTORE_PASSWORD with the password you want for your new Java keystore.
  • Replace YOUR_PKCS12_PASSWORD with the password you set when creating the .p12 file in Step 2.

Step 4: Verify your JKS Keystore

To ensure your certificate is correctly imported, use:

keytool -list -v -keystore keystore.jks

You should see your imported certificate details listed.

Step 5: Use your JKS Keystore

Now you can use keystore.jks in your Java application or server (like Tomcat, Jetty, Spring Boot applications, etc.).

Example configuration (Tomcat server.xml):

<Connector port="8443" protocol="HTTP/1.1"
           SSLEnabled="true"
           scheme="https" secure="true"
           keystoreFile="/path/to/keystore.jks"
           keystorePass="YOUR_KEYSTORE_PASSWORD"
           clientAuth="false" sslProtocol="TLS" />

Replace paths/passwords with your details.

Important notes:

  • Store your keystore securely and protect the passwords.
  • Let’s Encrypt certificates expire every 90 days, so automate renewal and conversion into JKS if possible.

That’s it! Your Let’s Encrypt certificate is now in JKS format, ready for Java applications.

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Fixing KeePassXC Snap Not Detecting YubiKey

 in Bash / GNU/Linux  tagged bash / GNU/Linux / KeePassXC / ubuntu / yubikey by

If you’re using KeePassXC installed from Snap and notice it’s not recognizing your YubiKey, you’re not alone. Snap packages have strict sandboxing and confinement rules that often block access to hardware devices like USB, including YubiKeys. This can cause issues when using features like Challenge-Response authentication with your YubiKey in KeePassXC.

This blog post’ll cover multiple ways to solve this problem, including switching to a different installation method or adjusting the Snap confinement settings.

Why Doesn’t KeePassXC (Snap) See the YubiKey?

Snap packages are sandboxed, which is great for security but can be problematic for applications that need direct access to hardware like USB devices. This restriction prevents KeePassXC from communicating with your YubiKey, as it requires access to your USB ports and smart card services.

Let’s explore different solutions to fix this issue.

Solution 1: Install KeePassXC from the Official PPA (Recommended)

Installing KeePassXC using the official PPA (Personal Package Archive) is the best way to avoid the Snap sandbox restrictions. This version doesn’t have the same hardware access limitations as the Snap version and is more likely to work seamlessly with your YubiKey.

Steps to Install KeePassXC via PPA:

  1. Remove the Snap Version
    First, you’ll want to remove the Snap version of KeePassXC if it’s currently installed:
   sudo snap remove keepassxc;
  1. Add the Official KeePassXC PPA
    Next, add the official KeePassXC PPA to your system and update your package list:
   sudo add-apt-repository ppa:phoerious/keepassxc;
   sudo apt-get update;
  1. Install KeePassXC from the PPA
    Now, install KeePassXC from the PPA:
   sudo apt-get install keepassxc;

This method bypasses the limitations of Snap and ensures full hardware access to devices like the YubiKey. After installation, KeePassXC should immediately detect your YubiKey.

Solution 2: Adjust Snap Confinement to Allow Hardware Access

If you prefer to stick with the Snap version of KeePassXC, you can adjust its permissions to allow access to the necessary system interfaces.

To enable USB and PC/SC (smart card) support for KeePassXC Snap, run the following commands:

sudo snap connect keepassxc:raw-usb;

This command allows the Snap package to access the USB device and observe hardware resources.

After running the commands, restart KeePassXC:

snap restart keepassxc;

This should grant KeePassXC Snap access to the YubiKey via USB and PC/SC protocols.

Solution 3: Use Classic Confinement for Snap (Less Secure)

Snap packages have strict confinement modes by default, but you can loosen these restrictions by installing KeePassXC in classic confinement mode. This allows the application to access your system as if it were a regular app installed outside of Snap, without the sandbox limitations.

Steps to Install KeePassXC with Classic Confinement:

  1. Remove the Existing Snap Version
    If you already have the standard Snap version of KeePassXC installed, remove it:
   sudo snap remove keepassxc;
  1. Install KeePassXC with Classic Confinement
    Now, reinstall KeePassXC with the --classic flag:
   sudo snap install keepassxc --classic;

By using --classic, you’re bypassing the tight confinement, which means KeePassXC will be able to access hardware devices like the YubiKey without the sandbox restrictions.

Note: This approach compromises some of the security benefits provided by Snap’s confinement model, so only use this method if you need it for specific reasons.

Solution 4: Use Flatpak as an Alternative to Snap

If you’re facing persistent issues with the Snap version of KeePassXC and don’t want to use the PPA, you can try installing KeePassXC via Flatpak. Flatpak offers a more flexible and modern sandboxing approach, and it often has better hardware access capabilities compared to Snap.

Steps to Install KeePassXC via Flatpak:

  1. Install Flatpak (if not already installed)
    First, install Flatpak on your system if you don’t have it yet:
   sudo apt-get install flatpak;
  1. Add the Flathub Repository
    Add the Flathub repository to your Flatpak sources:
   flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo;
  1. Install KeePassXC from Flathub
    Now install KeePassXC from the Flathub repository:
   flatpak install flathub org.keepassxc.KeePassXC;

Flatpak applications typically have more flexible access to hardware, so your YubiKey should work without issues after switching to this version of KeePassXC.

Solution 5: Ensure pcscd Is Running

YubiKeys often rely on the PC/SC daemon (pcscd) for smart card operations. If the daemon is not running, KeePassXC won’t be able to detect the YubiKey even if all permissions are set correctly.

To install and start pcscd:

  1. Install pcscd:
   sudo apt-get install pcscd;
  1. Start and enable the pcscd service:
   sudo systemctl start pcscd;
   sudo systemctl enable pcscd;

Ensure that pcscd is running and that your system recognizes the YubiKey through PC/SC.

Conclusion

The most reliable solution for getting KeePassXC to work with your YubiKey on Linux is to install KeePassXC from the official PPA. This eliminates the Snap confinement issues that often prevent hardware from being detected. Alternatively, adjusting Snap’s permissions or switching to Flatpak are also viable solutions.

Here’s a quick recap of the options:

  • PPA Installation (Recommended): Full access to hardware without Snap’s restrictions.
  • Snap Adjustments: Grant KeePassXC Snap permissions to access USB and PC/SC devices.
  • Classic Confinement: Loosen Snap restrictions (less secure).
  • Flatpak Installation: Another sandboxed app system, but with better hardware access.
  • Ensure pcscd is Running: Required for YubiKey smart card functionality.

With these solutions, you should be able to get KeePassXC and your YubiKey working together on your system.

Happy securing your passwords with YubiKey and KeePassXC!

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Configuring YubiKey for Challenge-Response with YubiKey Manager (ykman)

 in Bash / GNU/Linux  tagged bash / GNU/Linux / ubuntu / ykman / yubi / yubico / yubikey by

YubiKeys are popular hardware security keys for multi-factor authentication, passwordless login, and cryptographic operations. YubiKey Manager (ykman) is a versatile command-line tool that helps manage YubiKeys and configure various features, such as OTP (One-Time Passwords), FIDO2, OpenPGP, and more.

In this blog, we’ll walk through installing ykman, configuring the system to support smart card (CCID) functionality, and setting up YubiKey’s OTP Challenge-Response mechanism on Slot 2 with a custom secret key.

Prerequisites

Before you proceed, ensure you have:

  • A YubiKey (any model that supports OTP)
  • A Linux-based system (although similar commands apply for macOS and Windows)
  • Administrative privileges (i.e., sudo access)

Step 1: Install YubiKey Manager (ykman)

The easiest way to install ykman is through the Snap package system. Open your terminal and run the following command:

sudo snap install ykman

Snap packages offer the advantage of being automatically updated, and the installation process is streamlined across different Linux distributions.

Step 2: Install PC/SC Daemon (for Smart Card Functionality)

YubiKey’s advanced features such as PIV (Personal Identity Verification), OpenPGP, and OATH require the PC/SC daemon (pcscd). This daemon handles smart card communication and is crucial if you plan to use your YubiKey as a smart card device.

To install pcscd, run the following command:

sudo apt-get install pcscd

Once installed, ensure that the service is running:

sudo systemctl start pcscd
sudo systemctl enable pcscd

This ensures that the PC/SC daemon starts on boot and is ready to handle YubiKey interactions that require smart card protocols.

Step 3: Configure YubiKey OTP Slot 2 for Challenge-Response

YubiKeys supports OTP in two different slots. By default, Slot 1 is often used for standard Yubico OTP, while Slot 2 can be configured for custom purposes, such as Challenge-Response.

In this example, we will configure Slot 2 with a custom secret key for Challenge-Response using HMAC-SHA1. This key can be used in scenarios such as system authentication, password managers, or other cryptographic operations.

Generate or Define a Secret Key

For Challenge-Response to work, you need a 20-byte secret key in hexadecimal format. You can either generate this key yourself or use a tool like OpenSSL:

openssl rand -hex 20

Ensure you securely store this secret key, as it will be used for Challenge-Response authentication.

Configure Slot 2 with the Secret Key

To configure the secret key for Challenge-Response in Slot 2, use the following ykman command. Replace the example key with your own 20-byte key:

ykman otp chalresp 2 00112233445566778899aabbccddeeff00112233
  • otp chalresp tells YubiKey Manager that we are configuring OTP Challenge-Response.
  • 2 indicates Slot 2.
  • The hexadecimal string 00112233445566778899aabbccddeeff00112233 is your secret key.

Once this command runs successfully, your YubiKey is ready for Challenge-Response authentication in Slot 2.

Step 4: Verify the Configuration

To ensure that the configuration was successful, you can check the YubiKey’s slot status with the following command:

ykman otp info

This command will display information about both Slot 1 and Slot 2, allowing you to verify that Slot 2 has been configured for Challenge-Response using HMAC-SHA1.

Conclusion

You have now successfully installed ykman, configured your system for smart card support with pcscd, and set up Slot 2 on your YubiKey for OTP Challenge-Response using a custom secret key. This setup is valuable for integrating YubiKey into secure systems, password managers, and custom cryptographic workflows.

By leveraging ykman, you unlock a wide range of features in your YubiKey, making it a powerful tool for authentication and security.

For further reading on YubiKey and its capabilities, you can explore the official Yubico documentation.

Common Issues

  1. PC/SC Not Available: If you encounter the warning PC/SC not available. Smart card (CCID) protocols will not function., ensure that the pcscd service is installed and running. You can restart it using:
   sudo systemctl restart pcscd
  1. Permission Denied: If you experience permission issues when running ykman, ensure that your user has access to USB devices, or try running the command with sudo.

With this setup, your YubiKey is now ready to provide robust security for your systems and applications!

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Fixing GNOME Not Loading After Installing FUSE on Ubuntu

 in Bash / GNU/Linux  tagged bash / desktop / fuse / gnome / GNU/Linux / ubuntu by

Recently, I ran into an interesting issue while working on my Ubuntu system. After installing FUSE (Filesystem in Userspace), my GNOME desktop environment stopped loading, leaving me at a blank screen or stuck in a loop with no graphical interface. If you find yourself in a similar situation, don’t worry. This post walks you through the issue and provides a simple fix.

The Problem: GNOME Fails to Load After FUSE Installation

FUSE is a powerful tool that allows non-privileged users to create their own file systems without modifying the kernel code. However, after installing FUSE on my Ubuntu machine, I rebooted to find that the GNOME desktop environment wouldn’t load.

I tried rebooting several times, hoping the issue would resolve itself. Unfortunately, it didn’t. I could still access the terminal using Ctrl + Alt + F2, but my desktop environment was completely unresponsive. This kind of issue can often occur due to broken or missing desktop packages.

The Solution: Reinstall the ubuntu-desktop Package

The issue likely arose from a corrupted or missing GNOME/desktop package. The good news is that this is fixable with a simple command:

sudo apt install --reinstall ubuntu-desktop

This command reinstalls the GNOME desktop environment and other essential packages, restoring the graphical interface.

How to Apply the Fix

There are two main methods to fix the issue depending on your situation. Either you can use Recovery Mode to reinstall the desktop environment or you can do it from a terminal session using Ctrl + Alt + F2.

Method 1: Using Recovery Mode

Recovery Mode is your best option if you’re stuck at the GNOME loading screen and can’t access the terminal or graphical interface. Here’s how you can fix it:

  1. Reboot Your System and Enter Recovery Mode:
  • On system startup, hold down the Shift key to bring up the GRUB menu.
  • From the GRUB menu, select Advanced options for Ubuntu.
  • Select a kernel with the suffix (recovery mode).
  1. Enable Networking:
  • In the recovery menu, select network to enable networking. This is necessary because you will need access to the internet to download any missing or broken packages.
  1. Reinstall ubuntu-desktop:
  • Once networking is enabled, select the root option to drop into a root shell.
  • Run the following command:
    bash sudo apt install --reinstall ubuntu-desktop
  1. Reboot the System:
    After the installation is complete, reboot your system using the following command:
   sudo reboot

Your GNOME desktop should now load without any issues.

Method 2: Using a Second Terminal Session (Ctrl + Alt + F2)

If your system boots but the GNOME desktop environment does not load properly, you can fix the issue from a second terminal session.

  1. Open a Second Terminal:
  • Press Ctrl + Alt + F2 to open a new terminal session. This will allow you to log into a non-graphical session.
  1. Reinstall the Desktop Environment:
    Once logged in, run the following command to reinstall the desktop environment:
   sudo apt install --reinstall ubuntu-desktop
  1. Reboot:
    After the installation completes, reboot your system:
   sudo reboot

Once the system boots up again, GNOME should load as expected.

https://youtu.be/VrBgV178dMg

Why This Happens

The root cause of this issue is often related to the FUSE installation process modifying or corrupting some of the desktop environment packages. Installing FUSE doesn’t directly interfere with GNOME, but package conflicts or incomplete installations sometimes can break the environment. In this case, reinstalling ubuntu-desktop restores the missing components, resolving the issue.

Conclusion

If your GNOME desktop environment stops loading after installing FUSE, don’t panic. By either using the Recovery Mode or accessing a terminal via Ctrl + Alt + F2, you can quickly reinstall the ubuntu-desktop package and bring your system back to life. This solution should get your desktop environment running again without any data loss or the need for a complete reinstallation of Ubuntu.

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