Hello, I thought about how to work with cloud storage under Qubes OS and I'd like to share my idea with you, to provide feedback. I have already build a prototype that works "reasonable" well, but I am far away from being a security professional, as such I'd like to hear your opion about it. Assumptions: You are using cloud storage like Microsoft OneDrive and you would like to do so under Qubes in a more secure way. Goals: - all files within onedrive should be encrypted - files should still be accessible/decryption from other Operating systems - decrypted data storage and cloud storage access should be separated into two AppVMs - different AppVMs should have access to data in the cloud storage, but it's impossible for an AppVM to read the data which should be read by other AppVMs (meaning you have the option to create individuall encrypted directories) - solution should be easy to use and relying on scripts to provide good automation and a good tradeoff between security and user experience.
Idea: In order to reach the goals, the idea is to work with two AppVMs: 1. "Access+Transfer AppVM" this VM will access the cloud storage provider, provide synchronisation and will always see encrypted data 2. "Storage-AppVM" this VM will receive the encrypted files from the Access+Transfer AppVM and store the files. It will also work as a data-hub to provide access to data to your other AppVMs which you use to manipulate the data within this VM. As such we have separated: - Access & Transfer of data from cloud storage provider - Local data storage - Data manipulation Solution Design: [Access+Transfer AppVM] Template: fedora-25-minimal Additional packages: - OneDrive Freeclient ([https://github.com/skilion/onedrive)](https://github.com/skilion/onedrive) - sudo dnf -y install nfsutils Will be configured to mount a NFS-share from the Storage AppVM and to access OneDrive to synchronize the files Data will be downloaded and storad in the mounted NFS-Share of the Storage AppVM [Storage App-VM] Template: fedora-25-minimal Additional packages: - sudo dnf -y nfs-utils encfs This machine has been setup as a NFS Server. The /etc/exports file and also the iptables Firewall of this AppVM has been setup, so that the [Access+Transfer AppVM] kann access a certain location. Within this location all files ENCFS-encrypted. As such the Access+Transfer AppVM but also the Cloud Storage provider will only see encrypted files. Additional AppVMs can also mount the main NFS Share/directory. Those AppVMs can access certain subfolders and mount them via ENCFS to get the unecrypted data. So the ENCFS decryption are done in those AppVMs. You could setup various subfolders within your Onedrive directory and each folder could be encrypted within the different AppVMs. Example: onedrive\photos --> NFS Share to --> my-photo-appvm onedrive\work --> NFS Share to --> my-work-appvm onedrive\media --> NFS Share to --> my multimedia-appvm Let's look at one AppVM (example my-work-appvm = 10.137.2.25 // storage-appvm = 10.137.2.20) On sys-firewall there is a rule, so that the work-appvm can access the storage-appvm: [user@sys-firewall ~]$ sudo iptables -I FORWARD 2 -s 10.137.2.25 -d 10.137.2.20 -j ACCEPT On the storage appvm: [user@my-storage ~]$ sudo iptables -I INPUT 5 -i eth0 -s 10.137.2.25 -d 10.137.2.20 -j ACCEPT The NFS Exports file: [...] # 10.137.2.15 = Access+Transfer AppVM /var/nfs 10.137.2.15(rw,sync,no_subtree_check) # 10.137.2.25 = Work AppVM /var/nfs/work 10.137.2.25(rw,sync,no_subtree_check) [...] In the Work AppVM you are mounting the NFS Share from the Storage AppVM: sudo mount 10.137.2.20:/var/nfs/work /mnt/onedrive-work.encfs In Order to access the files, the NFS share is encfs-mounted: encfs /mnt/onedrive-work.encfs ~/work the unencrypted files can be accessed in ~/work. If saved they will be encfs-encrypted and stored to NFS share of the Storage AppVM. The Storage AppVM is connected to the Access-Transfer-AppVM which will recognize that an (encrypted) file has changed and will upload it to Onedrive. As you can guess, you can use different AppVMs, which access different subfolders with different ENCFS-Keys. For additional security you can also choose to shutdown the Access+Transfer AppVM and disable the NFS Server in the Storage AppVM if you don't need access to the files. Script to start the NFS Server from dom0 #!/bin/bash qvm-run my-storage 'xterm -e "sudo systemctl start nfs"' sleep 2 Scripts to unencrypt the data in an AppVM from dom0: #!/bin/bash qvm-run my-work 'xterm -e "encfs /mnt/onedrive-work.encfs ~/work"' Script to unmount the unencrypted share in an AppVM: #!/bin/bash qvm-run my-untrusted 'xterm -e "fusermount -u ~/work"' I have already a working prototype, regarding the NFS server and ENCFS-part and will now add the onedrive part. What's your opinion about this approach (I hope I could make clear what the idea is) - am I opening to much attack possibilities because I need to have NFS server running between the AppVMs? Keep in mind, that I am only sharing one directory, which is encrypted and only the AppVM knows how to decrypt the data. So even if the Storage AppVM gets compromissed, the data should be encrypted (and therof protected). The password entry within the AppVM to open of the ENCFS-encrypted data could be simplified by using something like a yubikey + short password. Interested to get your feedback. [799] -- You received this message because you are subscribed to the Google Groups "qubes-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to qubes-users+unsubscr...@googlegroups.com. To post to this group, send email to qubes-users@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/qubes-users/6DvyGkbeVdxW_S9ldo7aBB9-3eCmBB1qR-LeZ4hinGHKtJ1MfFZC377alFMUo9FoUbcHctNg7VpjWuIo0RHgcgvnNLCXhJWk_i5Z4XLLBL0%3D%40protonmail.com. For more options, visit https://groups.google.com/d/optout.
