WSL SSH Key Copier

wsl_copy_ssh_keys.sh

#!/bin/bash

#enable nullglob on startup if not enabled
shopt -q nullglob || shopt -s nullglob;

# Turns the given value into an array and verifies that the array has more than zero elements
# to check if the globbed file directory given exists
# requires nullglob to be  or it will enable/disable during the function execution
glob_exists() {
    shopt -q nullglob || (echo "nullglob must be enabled for glob_exists to work." && return 1);
    
    # shellcheck disable=SC2206
    #disable warning because we actually want uncontrolled glob expansion for this unusual use case
    arr=( $1 )
    [ ${#arr[@]} != 0 ]
}

if [ -n "$SSH_CLIENT" ] || [ -n "$SSH_TTY" ]; then
    echo "Skipping ssh key copy since this is an SSH session";
else

    #Setup host user profile variables
    win_userprofile="$(cmd.exe /c "<nul set /p=%UserProfile%" 2>/dev/null)"

    #win_userprofile_drive="${win_userprofile%%:*}:"

    #userprofile_mount="$(findmnt --noheadings --first-only --output TARGET "$win_userprofile_drive")"

    win_userprofile_dir="${win_userprofile#*:}"

    #userprofile="${userprofile_mount}${win_userprofile_dir//\\//}"

    #Copy ssh keys from windows to linux
    windows_ssh_dir="/mnt/c/$(echo "${win_userprofile_dir:1}" | sed 's/\\/\//g' | sed 's/://')/.ssh";

    echo "Copying ssh keys from $windows_ssh_dir";

    if [ -d "$windows_ssh_dir" ]; then
        cp --recursive --update "$windows_ssh_dir" ~;
    else 
        echo "Unable to copy .ssh directory from Windows to Linux."
    fi

    if [ -d "$HOME/.ssh" ]; then
        chmod 700 ~/.ssh;

        #By default all files are given restrictive owner only permissions
        if glob_exists "$HOME/.ssh/*"; then
            chmod -R 600 ~/.ssh/*;
        else
            echo "The .ssh copy succeeded but there were no files in the .ssh folder";
        fi
    
        #Make a more permissive permission for public keyfiles, if there are any    
        if glob_exists "$HOME/.ssh/*.pub"; then
            chmod -R 644 ~/.ssh/*.pub;
        fi

        #Make a more permissive permission for config files for ssh service
        if [ -f "$HOME/.ssh/authorized_keys" ]; then
            chmod 644 ~/.ssh/authorized_keys;
        fi
        if [ -f "$HOME/.ssh/known_hosts" ]; then
            chmod 644 ~/.ssh/known_hosts;
        fi
        if [ -f "$HOME/.ssh/config" ]; then
            chmod 644 ~/.ssh/config;
        fi
    else
        echo "Unable to find .ssh directory for permissions fixes. Perhaps the copy failed?";
    fi

fi