[MIR] nullboot

Bug #1965115 reported by Julian Andres Klode
16
This bug affects 1 person
Affects Status Importance Assigned to Milestone
nullboot (Ubuntu)
In Progress
Undecided
Unassigned

Bug Description

[Availability]
nullboot is available in jammy universe on amd64 and arm64, which are the only architectures we care about it for the foreseeable future

It currently builds and works for architetcures: arm64

Link to package https://launchpad.net/ubuntu/+source/nullboot

[Rationale]
nullboot is required for enabling a partner cloud offering with linux-azure-fde

[Security]
nullboot is a new software produced by Canonical. It produces a Go binary that measures boot binaries and does some sealing, to allow automatic full disk encryption. It only operates on trusted data (firmware data and kernels in /usr/lib/linux/efi).

- no `suid` or `sgid` binaries
- no executables in `/sbin` and `/usr/sbin`
- Package does not install services, timers or recurring jobs
- Package does install a dpkg trigger on /usr/lib/linux/efi
- Packages does not open privileged ports (ports < 1024)
- Packages does not contain extensions to security-sensitive software

[Quality assurance - function/usage]
This package is not usable on its own, it needs a kernel.efi package to be installed such as linux-azure-fde. It requires a TPM.

[Quality assurance - maintenance]
Foundations maintains this software

[Quality assurance - testing]
The test suite run at build time covers about 80% of the code. The code was mostly developed using a test-driven development approach, including abstractions of file system and EFI variables to allow for extensive testing.

ok github.com/canonical/nullboot/efibootmgr 0.142s coverage: 81.6% of statements

The same test suite is run as an autopkgtest. End-to-end testing should be done by consumers of nullboot such as linux-azure-fde, but is very involved as it needs to happen in a qemu with tpm setup and stuff, so it might not happen.

[Quality assurance - packaging]
Lintian is a bit overly protective, but

W: nullboot-dbgsym: elf-error In program headers: Unable to find program interpreter name [usr/lib/debug/.build-id/03/d7295826b5850df200032deca916f3d07a46ff.debug]
W: nullboot: hardening-no-pie [usr/bin/nullbootctl]

^- Go toolchain worries

W: nullboot: no-manual-page usr/bin/nullbootctl

^- maybe it would be nicer to have it live in usr/libexec, I don't know.

W: nullboot: unknown-field Important
W: nullboot: unknown-field Protected

^- these are to be expected.

- Lintian overrides are not present
- debian/watch is not present because it is anative package
- This package does not rely on obsolete or about to be demoted packages.
- This package has no python2 or GTK2 dependencies

- The package will be installed by default, but does not ask debconf
  questions higher than medium (no questions, installed only on select cloud images)
- Packaging and build is easy, https://github.com/canonical/nullboot/tree/ubuntu/main/debian

[UI standards]
- Application is not end-user facing (does not need translation)
Application is not _exactly_ end user interfacing, and certainly does not have translations. It runs as part of triggers when select kernel packages are installed and might log some messages there.

[Dependencies]
 - No further depends or recommends dependencies that are not yet in main

[Standards compliance]
- This package violates Debian Policy, it vendorizes various Go libraries (in a orig-vendor.tar.gz)

[Maintenance/Owner]
- Owning Team will be Foundations
- Team is not yet, but will subscribe to the package before promotion

- The team Foundations is aware of the implications by a static build and
  commits to test no-change-rebuilds and to fix any issues found for the
- The team Foundations is aware of the implications of vendored code and (as
  alerted by the security team) commits to provide updates to the security
  team for any affected vendored code for the lifetime of the release
  (including ESM).

[Background information]
The upstream nullboot project and packaging branches are located at https://github.com/canonical/nullboot

Tags: sec-976
description: updated
description: updated
Changed in nullboot (Ubuntu):
assignee: nobody → Ioanna Alifieraki (joalif)
Revision history for this message
Ioanna Alifieraki (joalif) wrote :
Download full text (3.3 KiB)

Review for Package: nullboot

[Summary]
nullboot is a boot manager for environments that do not need a boot manager.
Instead of running a boot manager at boot, it directly manages the UEFI boot entries for you.
It produces a Go binary that measures boot binaries and does some sealing,
to allow automatic full disk encryption.
It only operates on trusted data (firmware data and kernels in /usr/lib/linux/efi).

MIR team ACK

This does need a security review, so I'll assign ubuntu-security (package deals with security attestation)

List of specific binary packages to be promoted to main: nullboot_0.3.0-0ubuntu1_amd64

Notes:
Recommended TODOs:
1. It would be nice to have a test plan for end-to-end testing.

- The package should get a team bug subscriber before being promoted

[Duplication]
- There is no other package in main providing the same functionality.

[Dependencies]
OK:
- no other Dependencies to MIR due to this
    - checked with check-mir
    - not listed in seeded-in-ubuntu
    - none of the (potentially auto-generated) dependencies (Depends
      and Recommends) that are present after build are not in main
- no -dev/-debug/-doc packages that need exclusion
- No dependencies in main that are only superficially tested requiring
   more tests now.

Problems: None

[Embedded sources and static linking]
OK:
- does not have odd Built-Using entries
- Go Package that follows the Debian Go packaging guidelines
- vendoring is used, but the reasoning is sufficiently explained
- golang: static builds are used, the team confirmed their commitment
   to the additional responsibilities implied by static builds.

Problems: None

[Security]
OK:
- history of CVEs does not look concerning
- does not run a daemon as root
- does not use webkit1,2
- does not use lib*v8 directly
- does not parse data formats
- does not open a port/socket
- does not process arbitrary web content
- does not use centralized online accounts
- does not integrate arbitrary javascript into the desktop
- does not deal with system authentication (eg, pam), etc)

Problems:
- does deal with security attestation (secure boot, tpm, signatures)

[Common blockers]
OK:
- does not FTBFS currently
- does have a test suite that runs at build time
- test suite fails will fail the build upon error.
- does have a non-trivial test suite that runs as autopkgtest
- no new python2 dependency
- Go package, but using dh-golang

Problems: None

[Packaging red flags]
OK:
- Ubuntu does not carry a delta
- symbols tracking not applicable for this kind of code.
- d/watch is present and looks ok (if needed, e.g. non-native)
- Upstream update history is good
- Debian/Ubuntu update history is good
- the current release is packaged
- promoting this does not seem to cause issues for MOTUs that so far
   maintained the package
- no massive Lintian warnings
- d/rules is rather clean
- It is not on the lto-disabled list

Problems: None

[Upstream red flags]
OK:
- no Errors/warnings during the build
- no incautious use of malloc/sprintf (as far as we can check it)
- no use of sudo, gksu, pkexec, or LD_LIBRARY_PATH (usage is OK inside
   tests)
- no use of user nobody
- no use of setuid
- no important open bugs...

Read more...

Changed in nullboot (Ubuntu):
assignee: Ioanna Alifieraki (joalif) → nobody
assignee: nobody → Ubuntu Security Team (ubuntu-security)
Steve Beattie (sbeattie)
tags: added: sec-976
Revision history for this message
Luís Infante da Câmara (luis220413) wrote (last edit ):

The first Lintian warning is due to a bug in dh_strip (bug #1977883).

Revision history for this message
Seth Arnold (seth-arnold) wrote :

Hello, this is just a note that the security team is unlikely to review this in time for 22.10. Sorry.

Revision history for this message
Spyros Seimenis (sespiros) wrote :
Download full text (4.2 KiB)

I reviewed nullboot 0.4.0-0ubuntu1 as checked into kinetic. This shouldn't be
considered a full audit but rather a quick gauge of maintainability.

nullboot is a specialized lightweight boot manager for environments that don't need one. It works by directly managing the UEFI boot entries. For TPM enabled systems, it also handles the resealing
of the disk encryption key to support boot asset update operations.

- CVE History:
  - No
- Build-Depends?
  - boot and secure boot related libraries
      - canonical/go-efilib
      - canonical/go-tpm2
      - canonical/tcglog-parser
      - snapcore/secboot
  - crypto libraries
      - go.mozilla.org/pkcs7
      - golang.org/x/crypto
- pre/post inst/rm scripts?
  - single postinst script which runs nullbootctl
- init scripts?
  - No
- systemd units?
  - No
- dbus services?
  - No
- setuid binaries?
  - No
- binaries in PATH?
  - /usr/bin/nullbooctl
- sudo fragments?
  - No
- polkit files?
  - No
- udev rules?
  - No
- unit tests / autopkgtests?
  - efibootmgr folder contains an extensive test suite
  - no testsuite for the main application
- cron jobs?
  - No
- Build logs:
  - Warnings:
    - dh_auto_install: warning: LTO opimize is enable in buildflags. But cgo doesn't support it. LTO flags will be stripped in cgo.
    - dh_golang: warning: LTO opimize is enable in buildflags. But cgo doesn't support it. LTO flags will be stripped in cgo.
    - dpkg-gencontrol: warning: package nullboot: substitution variable ${misc:Static-Built-Using} unused, but is defined
    - update-rc.d: warning: start and stop actions are no longer supported; falling back to defaults
  - Lintian warnings:
    - W: nullboot: no-manual-page [usr/bin/nullbootctl]
    - W: nullboot source: unknown-field Go-Import-Path
    - W: nullboot: unknown-field Important
    - W: nullboot: unknown-field Protected
- Processes spawned?
  - multiple calls to Go's `exec.Command` in vendored Go libraries. No issues identified.
- Memory management?
  - Written in Go. No issues identified.
- File IO?
  - No issues.
- Logging?
  - No issues.
- Environment variable usage?
  - only in unreachable paths in vendored code. No issues.
- Use of privileged functions?
  - only in unreachable paths in vendored code. No issues.
- Use of cryptography / random number sources etc?
  - Go's crypto library for hashing.
- Use of temp files?
  - Creation of temp files (where applicable) is done inside trusted directories.
- Use of networking?
  - No
- Use of WebKit?
  - No
- Use of PolicyKit?
  - No

- Any significant cppcheck results?
  - No
- Any significant Coverity results?
  - No. Multiple of low impact in vendored code mostly (see attached coverity.txt for a full list)
- Any significant shellcheck results?
  - No
- Any significant bandit results?
  - No
- govulncheck
  - No. 4 vulnerabilities of negligible impact.
- gosec
  - No but
  - several unhandled errors reported such as (see attached gosec.txt for a full list):
    - efibootmgr/bootmgr.go|122 col 2| binary.Write(optionalData, binary.LittleEndian, efi.ConvertUTF8ToUCS2(entry.Options+"\x00"))
    - efibootmgr/reseal.go|183 col 2| binary.Write(h, binary.LittleEndian, uint32(0))

Most of the automated tool...

Read more...

Changed in nullboot (Ubuntu):
assignee: Ubuntu Security Team (ubuntu-security) → nobody
Revision history for this message
Christian Ehrhardt  (paelzer) wrote :

This is ready to promote, but not showing up as component mismatch right now. Setting "in progress" to reflect that.

Changed in nullboot (Ubuntu):
status: New → In Progress
Revision history for this message
Christian Ehrhardt  (paelzer) wrote :

You can also prepare an answer to the test plan that you were asked for (in addition to making the change that pull this in).

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