== Summary ==
Include Grub's "verify," "cryptodisk" and "luks" modules in
grubx64.efi of the 'grub2-efi-x64' package.
Note: Although the build process will automatically include explicit
dependencies ("mpi," "gcry_sha1," "procfs" and "archelp"), the
following implicit ones must also be included: "gcry_sha256,"
"gcry_rsa," "gcry_rijndael," "gcry_serpent," gcry_twofish" and
== Owner ==
* Name: [[User:benjamind|Benjamin Doron]]
* Email: benjamin.doron00(a)gmail.com
* Name: [[User:pjones|Peter Jones]]
* Email: pjones(a)redhat.com
* Name: [[User:javierm|Javier Martinez Canillas]]
* Email: fmartine(a)redhat.com
== Detailed Description ==
Users utilising secure boot functionality on the UEFI platform cannot
insert grub modules. Paradoxically, this means that security-conscious
users cannot use grub's verify module for signature verification, or
employ (near) full disk encryption using cryptodisk and luks.
The security benefits of signature verification would reach more users
if Fedora automated it by incorporating the process into
`grub2-mkconfig`. Similarly, it would be easier to use cryptodisk
functionality if it were configurable by anaconda. This can be
considered for future releases, after allowing time to straighten out
the details of the implementation and analyse the benefits/costs.
For the long-term, to grant flexibility with grub2 modules on secure
boot instances in general, it may be advisable to consider signing the
.mod files in the 'grub2-efi-x64-modules' package, allow inserting of
signed modules in secure boot instances and then modify
`grub2-mkconfig` to copy the necessary modules into the EFI partition
when required by the user's configuration.
== Benefit to Fedora ==
This change will allow users to gain trust in the integrity of
early-launch code either through verification of signatures
(particularly useful for the initramfs, which is particularly
vulnerable to possible offline modification) or encryption of the boot
== Scope ==
* Proposal owners: Modify grub.macros file to include the
above-mentioned modules in the GRUB_MODULES variable.
* Other developers: N/A (not a System Wide Change)
* Policies and guidelines: N/A (not a System Wide Change)
* Trademark approval: N/A (not needed for this Change)
== Upgrade/compatibility impact ==
Change only adds modules, so existing users should have no problems.
== How To Test ==
<b>Disclaimer: Commands assume that tester is root. Secure Boot must
be disabled for testing purposes (`insmod` is forbidden under Secure
Boot, for now. The description details a tentative plan to get us to a
place where that can be changed). Ensure that the package
'grub2-efi-x64-modules' is installed, and for testing purposes, copy
the contents to the EFI partition with `cp -r
1. Generate an RSA signing key with `gpg --full-generate-key` (option
4), then export it with `gpg --export > pubkey` and move it to the EFI
partition with `mv pubkey /boot/efi/EFI/fedora`. You can also export
the private key (`gpg --export-secret-keys > seckey`), but the signing
process doesn't require it as gpg will get the key from its own
2. Add "insmod verify," "insmod gcry_sha256," "insmod gcry_rsa,"
"trust (hd0,gpt1)/efi/fedora/pubkey" (change this based on your
environment) and "set check_signatures=enforce" to
3. Run `grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg`
4. Run `export GPG_TTY=$(tty)`. Don't ask, apparently something
changed in gpg with a recent update.
4. Create a file, /dev/shm/pass, with the key's password and execute:
`for x in $(find /boot -name "*.cfg" -or -name "*.lst" -or -name
"*.mod" -or -name "vmlinuz*" -or -name "initramfs*" -or -name
"grubenv"); do gpg --batch --pinentry-mode loopback --detach-sign
--passphrase-fd 0 $x < /dev/shm/pass; done`. Then, `shred
5. Reboot. If the system starts, backup and remove .sig files. If the
system does not start this time, change is successful
(To recover from a now non-booting system, open the grub terminal and
execute `set check_signatures=no`. The system should then boot, and
.sig files can be replaced or regenerated.)
<b>For cryptodisk functionality:</b>
1. Backup the files in your boot partition
2. Run `cryptsetup luksFormat /dev/sda2 --type luks1` (change this
based on your environment to /boot's block device)
Note: If filesystem root is also encrypted, it is recommended that the
same password be used for boot as for root to decrease the amount of
engagement required at start-up. Consider using --iter-time with low
time in milliseconds (default is 2000ms)
3. Open luks container with `cryptsetup luksOpen /dev/sda2 --type
luks1 crypt_boot` (change this to match your environment) and run
`mkfs.ext4 /dev/mapper/crypt_boot`, then mount and restore backup
4. Add "GRUB_ENABLE_CRYPTODISK=y" to /etc/default/grub
5. Correct /etc/fstab to the correct UUID for /boot
6. Add an entry for the boot container to /etc/crypttab (i.e.
"luks-<your luks UUID> UUID=<your luks UUID> none discard"), then run
`dracut -vf --regenerate-all`
7. Run `grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg`
8. Reboot. Grub should ask for the password created in step 2. If the
system then starts, change is successful
(If filesystem root is also encrypted, the user will be asked for a
password twice. This can be mitigated with a keyfile for filesystem
root, or use of the clevis package and likely, a tpm.)
== User Experience ==
Users may optionally elect to guarantee the integrity of boot code
either through verification of digital signatures or encryption of the
== Dependencies ==
'Grub2-efi-x64-modules' and 'grub2-tools-*' depend upon/are a part of
this package, but require no change.
== Contingency Plan ==
* Contingency mechanism: Revert the shipped configuration
* Contingency deadline: Beta freeze
* Blocks release? N/A (not a System Wide Change)
* Blocks product? No
== Documentation ==
== Release Notes ==
Fedora now supports Grub's detached verify and cryptodisk
functionality natively, even on secure boot systems.
He / Him / His
Fedora Program Manager
As per https://fedoraproject.org/wiki/Changes/RPM-4.15, rpm 4.15-alpha
will be hitting rawhide soon. A soname bump is involved but Igor kindly
promised to handle rebuilding all dependent packages as part of the
change, so no further action required from others on that account.
There are some other things that will require actions from others however:
A pile of language-specific macros and scripts have been eliminated from
rpm upstream, notably %__python and %__perl and everything built around
them, such as %python_sitelib and %perl_sitelib and their relatives.
Python packages should be using the version specific macros already,
provided by respective pythonN-devel packages so this shouldn't be an
issue. On perl-side, those macros have been temporarily added to
redhat-rpm-config instead to avoid breaking things right now, later to
be moved to final destination in perl-macros or such.
Another major change is in Python bindings where Python 3 is now
properly supported. In all the previous versions where Python 3 bindings
were buildable and available, string data from header was returned as
bytes, but the rest of the API expects strings so nothing really works
(see https://bugzilla.redhat.com/show_bug.cgi?id=1693751). To make it
worse, it was incompatible with every single rpm-python script ever
written. Usually when something is unusably broken, silence means that
it's not being used, otherwise people do complain. Not so in this case,
the absurd API has been there for almost ten years and people have
adopted to it with zero complaints. In short, rpm-python users still
supporting both Python 2 and 3 are generally compatible with this
change, but Python 3-only projects have out of necessity adopted to the
broken API and will now need to change. The most critical distro
components have more or less already been adopted, but here's more work
to do on this front. This fixed interface will be made available to
4.14.x somehow too, but the details are yet unclear. Because of that,
we'd suggest only patching packages in rawhide to work with the change
right now, and deal with upstreams once dust settles a bit.
Other than that, a major new thing is introduction of some parallel
operations in rpmbuild itself. Testing hasn't shown anything odd but
with threads and all, you never know. Keep your eyes open.
More info and details available in the preliminary release notes at
https://rpm.org/wiki/Releases/4.15.0 and the change page linked at the
start of this message.
- Panu -