>>14:31:51 <otaylor> ryanlerch: I think it's definitely possible (finicky, but sometimes you have to do finicky things...) to determine whether a password is possible to type at the bootloader password prompt Literally GRUB2 asking for a passphrase, implies /boot is encrypted. I'm not sure that's supportable. Anaconda has various limitations where it will require a separate boot volume. What are the advantages to encrypting boot?

Right now if you have autologin enabled, then GDM will use the password you typed at the luks screen to unlock the gnome-keyring in the user's session.

On Tue, Dec 4, 2018 at 2:19 PM, Ray Strode <rstrode(a)redhat.com&gt; wrote: > Right now if you have autologin enabled, then GDM will use the > password you typed at the luks screen to unlock the gnome-keyring > in > the user's session. Well this requires 3.30.2 and rawhide and F29 are both on 3.30.1 still. But it should work soon, yes. _______________________________________________ desktop mailing list -- desktop(a)lists.fedoraproject.org To unsubscribe send an email to desktop-leave(a)lists.fedoraproject.org Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/desktop@lists.fedoraproject...

> Log: > https://meetbot.fedoraproject.org/fedora-meeting-2/2018-12-03/workstation... > * Default disk partitioning layout for Workstation (mcatanzaro, > 14:11:08) > * ACTION: otaylor form a subgroup to look at LUKS issue -- WG is not > taking any specific actions until subgroup recommends something > (stickster, 14:41:48) > * LVM and /home partioning issues will depend on subgroup report > recommendation for LUKS (stickster, 14:44:00) - If only /home is encrypted, it requires a separate filesystem/volume for /home. - The main purpose of dropping LVM is to address the small root running out of space with flatpak installations in https://pagure.io/fedora-workstation/issue/54 - If separate home, then issue 54 needs a different solution. e.g. increase root size above 50G. However, some people will have workflows where they run out of space on root or home, no matter what we pick, just due to mismatching expectations. The problem will be more common for the dual boot and small physical device cases (many laptops have 128G SSD drives in their base configuration); and in particular when both uses cases happen simultaneously. Alternatives: a. Combined root and home, encrypt that volume (everything). b. Combined root and home, do not encrypt. For what it's worth, Windows 10 and macOS 10.13 do not encrypt anything by default. c. LVM thin provisioning doesn't really solve anything out of the box, because right now Anaconda won't permit over provisioning, therefore we still can run into the problem in issue 54. Only users with esoteric knowledge will know or be able to explain how to overprovision root and/or home volumes, to avoid or fix the problem in issue 54. d. ext4 encryption by default in only /home Regarding a.) with LUKS/LUKS2. The convention is to have a single device encryption passphrase shared among users, and this passphrase is different than the user login passphrase. I think this is a half assed UI/UX, having to enter two passphrases. It's archaic, and not worth any additional effort. People who manually tick the box in Anacond to encrypt, pretty much know what they're signing up for, which is this cockamamie UI/UX that doesn't exist on any other platform. A better approach requires: - Anaconda needs to know how to use a single passphrase for both LUKS and user login and how to associate user with LUKS key slot. - Likely a format change for /etc/passwd or some other file, to associate user login and LUKS key slot; while a passphrase could be cached and LUKS cryptsetup will use any offered without reference to a user, we need to know which slot to wipe when changing passphrases, therefore it has to be tracked. - GDM needs to know how to use single passphrases to both login and unlock volume. - If full disk encryption, rather than home only encryption, plymouth or GDM login or something like it needs to become available in early boot, i.e. part of the initramfs. This should present a user login, capture credential one time, and both unlock the encrypted volume and then login the user in one shot. Regarding d.) both f2fs and ext4 support file level encryption via fscrypt, and is used by newer Android devices by default. This can be done on a directory or file specific basis. And the file encryption passprase can be tied to the user login passprase. Anaconda and GDM work is implied to support anything related to fscrypt. Both a.) and d.) have the liability that the passphrase encoding method needs to somehow be made consistent and reliable no matter what language or keyboard layout is chosen when setting or changing that phrase; because as mentioned, nuking people's data by effectively locking their data behind an unknown or unknowable passphrase encoding, is bad. Worst case scenario is to at least inform the user that the selected language and/or keyboard can't be used to unlock the encrypted data; and also inform the user which language and/or keyboard they need to switch to, to make it possible, and to give them the UI necessary to do that. >> 14:31:51 <otaylor> ryanlerch: I think it's definitely possible (finicky, but sometimes you have to do finicky things...) to determine whether a password is possible to type at the bootloader password prompt Literally GRUB2 asking for a passphrase, implies /boot is encrypted. I'm not sure that's supportable. Anaconda has various limitations where it will require a separate boot volume. What are the advantages to encrypting boot? disadvantages: - there is presently no GRUB2 GUI, it's really clunky in appearance - it implies the user will have to do dual passphrase entry, once at the bootloader and again when logging in, this is also clunky Maybe a ~5 year view and plan are needed to better understand the problems, solutions, and what resources are available.

FWIW I think that putting the entirety of gdm in the initrd is a bad idea,

Javier and Peter (added to the Cc) have been working on making full-disk encryption storing the secret in the tpm work. This is what Windows with bitlocker does and what most smart phones do now (more or less).

The tpm hashes all these hashes together and when the kernel wants to access the encrypted root filesystem, it asks the tpm for the key, if all the hashes together match what the tpm expects it will give the key. This means that even if someone steals the entire laptop he cannot modify anything, the rootfs is crypted so it cannot be modified without the key and everything which comes before it is hashed so it cannot be replaced either. This leaves the attacker essentially stuck at the gdm login prompt. An advanced adversary will certainly be able to find a way around this, but it is a good level of security to start with.

On top of this we could do what Ubuntu does and encrypt home directories at the filesystme level using the password the user uses to login to protect/unlock the key for this. The downside of this is that all the file metadata (filename, size) is not encrypted, but the contents is and this would come *on top of* the full disk encryption using the tpm. The advantage of using filesystem level per file encryption this way is that it avoids the diskspace problem entirely.

FWIW I think that putting the entirety of gdm in the initrd is a bad idea, esp. since we rely on firmware calls to load the initrd and some firmwares are very stupid doing this sector by sector making initrd loading quite slow already making the initrd huge will make this problem much worse.

Hi, On 05-12-18 23:58, Chris Murphy wrote: > On Wed, Dec 5, 2018 at 1:20 PM Hans de Goede <hdegoede(a)redhat.com&gt; wrote: > >> Javier and Peter (added to the Cc) have been working on making >> full-disk encryption storing the secret in the tpm work. >> >> This is what Windows with bitlocker does and what most smart phones >> do now (more or less). > > Is this broadly supportable? > a. Macs don't have TPMs I'm not sure if that is true for older macs, and getting Linux to run on a Mac has been getting harder and harder for newer models anyways.

> b. Windows laptops have TPM 2.0 which I can't get to work on Linux > (works fine on Windows 10). > https://bugzilla.kernel.org/show_bug.cgi?id=185631 The work by Javier and Peter is targetting TPM2.0

> c. Can a TMP be reliably shared by both Windows and Fedora in a dual > boot configuration? Javier, Peter, can you answer this please ? > Whatever we're going to do by default needs to be broadly supported. > And also we need to define broadly supported. Is leaving 20% behind > acceptable? What's the fallback for them, and then why is that > fallback not good enough for everybody else by default? The fallback would be to allow then to set a diskcrypt password which will get asked for by plymouth from the initrd just as we have today.

> I must be > missing something. Even Bitlocker requires a user PIN at least to > unlock the volume. That is not true I've a Windows 10 tablet lying next to me which has an encrypted bitlocker volume which automatically unlocks at boot (it boots directly to the Windows desktop) but as soon as I turn of secure boot, it will no longer boot asking for the bitlocker recovery password and also Linux cannot read it.

>> FWIW I think that putting the entirety of gdm in the initrd is a bad >> idea, esp. since we rely on firmware calls to load the initrd and >> some firmwares are very stupid doing this sector by sector making >> initrd loading quite slow already making the initrd huge will make >> this problem much worse. > > I can't imagine it has to be that big. macOS has base "chooser" window > UI, with smooth rendering and animations, used in three contexts: as > the boot manager built into the firmware, as the login window built > into the bootloader when FileVault 2 is enabled, and the login window > when FileVault 2 is not enabled. At least the bootmanager only shows Icons for the OS, so no internationalization problems, also no input method issues. I do not know about the other parts, does FileVault2 do fully internationalized passwords ?

Anyways this is really comparing apples to oranges, Apple has full vertical integration and has a R&D budget in the 100s millions with more developers working on a single part of a piece of the stack then we have working on the entire stack. If you give us such a budget and/or such an amount of manpower I'm sure we can come up with something really nice too.

One important thing to keep in mind here which people seem to be forgetting is that security is always about striking a balance between usability and security an absolute secure system will also be absolutely unusable. With Fedora we add a third dimenstion of having a clearly limited amount of manpower to implement whatever we come up with.

IMHO doing full disk encryption with the key managed by the TPM2, combined with ecryptfs encryption for the homedir strikes the best balance in all 3 dimensions. Note that even then there still is quite a bit of work to do before we get there.