#19 Allow for adding user/pass via vrde external (VBoxAuthSimple )

[crash0veride]

External VRDP authentication allows for entering a username and password(stored hashed in vm extradata) via VBoxAuthSimple for a VM (VBox user manual CH7 - 7.1.5. RDP authentication). It would be handy to be able to configure this and enter a user/pass via the Web UI to secure a vrde head of a VM if so desired.

[Denis Kozlov]

For the reference:

Chapter 7. Remote virtual machines. 7.1.5. RDP authentication
https://www.virtualbox.org/manual/ch07.html#vbox-auth

1. Enable VBoxAuthSimple with the following command:
   $ VBoxManage setproperty vrdeauthlibrary "VBoxAuthSimple"

2. To enable the library for a particular VM, you must then switch authentication to external:
   $ VBoxManage modifyvm "<vm>" --vrdeauthtype external

3. Obtain the hash value for your desired password:
   $ VBoxManage internalcommands passwordhash "<password>"

4. Configure users and passwords (hashes) by writing items into the machine's extradata:
   $ VBoxManage setextradata "<vm>" "VBoxAuthSimple/users/<user>" <hash>

Replace <vm> with the VM name or UUID, <user> with the user name who should be allowed to log in, <password> with your desired password and <hash> with the encrypted password.