SSH private key auth on Windows 10 Bash

Question

i have some Linux installed on by Laptop and use SSH with private key authentication to connect to a server. Recently, I installed Win10 with the bash developer extension on by desktop. Since I only have one user account on this server, and hence only on key, i simply moved by private key file into the respective directory of my windows bash.

However, whenever I open a new bash instance and try to connect to the server, the error message: 'Permission denied (publickey).' is returned. My current fix are the following steps: exec ssh-agent bash; ssh-add;

While I could obviously add this into .profile, I would be required to enter the passphrase whenever I open bash.

Does anyone has some suggestions how to fix this more properly, s.t. I only have to enter my passphrase whenever I connect to the server and that I do not have to reinitialize my ssh key in every bash session.

kind regards

Answer 1

Keys must only be accessible to the user they're intended for and no other account, service, or group.

• I don't use WSL, as it's a security nightmare, creating more problems than it solves, so I'll provide both ways to set correct permissions

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Windows Powershell Terminal

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• GUI:
  • [File] Properties - Security - Advanced
    1. Set Owner to the key's user
    2. Remove all users, groups, and services, except for the key's user, under Permission Entries
    3. Set key's user to Full Control

• CLI:

  :: Set Variable ::
  set key="C:\Path\to\key"
  
  :: Remove Inheritance ::
  cmd /c icacls %key% /c /t /inheritance:d
  
  :: Set Ownership to Owner ::
  cmd /c icacls %key% /c /t /grant %username%:F
  
  :: Remove All Users, except for Owner ::
  cmd /c icacls %key%  /c /t /remove Administrator BUILTIN\Administrators BUILTIN Everyone System Users
  
  :: Verify ::
  cmd /c icacls %key%
  

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WSL Bash Terminal

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• CLI

  # Set Variables
  
    # Key  
      key="/path/to/key"
  
    # User:
      user="$(echo $USER)"
  
  # Set Ownership
    # This assumes user's name is also user's group name
      chown $user:$user $key
  
  # Set Access Rights
    chmod 0600 $key
  
  # Verify
  ls -l $key