Ubuntu
shim package

shim executes GRUB w/ dirty instruction cache on arm64

Bug #1987541 reported by dann frazier
10
This bug affects 1 person
Affects Status Importance Assigned to Milestone
shim (Ubuntu)
Fix Released
High
Unassigned
Bionic
Fix Released
Undecided
Unassigned
Focal
Fix Released
Undecided
Unassigned
Jammy
Fix Released
Undecided
Unassigned
Kinetic
Fix Released
Undecided
Unassigned

Bug Description

[Impact]
On arm64 platforms, GRUB may occasionally crash after being executed by shim. We're seeing it on the order of 1/100 boots.

[Test Case]
Put an arm64 server in a reboot loop. We're seeing this w/ a Cortex A72-based system (Nvidia Bluefield).

[Fix]
https://github.com/rhboot/shim/commit/5c537b3d0cf8c393dad2e61d49aade68f3af1401

[What could go wrong]
The only negative here would seem to be the performance impact of flushing the cache, which is unlikely to be noticeable.

See original description

Related branches

~juliank/shim/+git/shim-signed:alternatives
Steve Langasek: Approve
Ubuntu Stable Release Updates Team: Pending requested
Diff: 336 lines (+190/-9)
12 files modified
Makefile (+7/-3)
debian/changelog (+18/-0)
debian/control (+2/-2)
debian/kernel-postinst.d/zz-shim (+6/-0)
debian/shim-signed.install (+4/-1)
debian/shim-signed.postinst (+91/-3)
debian/shim-signed.triggers (+1/-0)
debian/tests/control (+3/-0)
debian/tests/test-is-not-revoked (+6/-0)
external-shimaa64.efi.previous (+1/-0)
external-shimx64.efi.previous (+1/-0)
is-not-revoked (+50/-0)

CVE References

dann frazier (dannf)
description: updated
Matthieu Clemenceau (mclemenceau)
tags: added: foundations-triage-discuss
Julian Andres Klode (juliank)
Changed in shim (Ubuntu):
importance: Undecided → High
tags: removed: foundations-triage-discuss
Revision history for this message
dann frazier (dannf) wrote :

This is now fixed upstream.

description: updated
Changed in shim (Ubuntu):
status: New → In Progress
Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package shim - 15.7-0ubuntu1

---------------
shim (15.7-0ubuntu1) kinetic; urgency=medium

  * New upstream version 15.7 (LP: #1996503), highlights:
    - Enable TDX measurements (LP: #1995852)
    - Flush the memory region from i-cache before execution (LP: #1987541)
    - Introspectable SBAT payload for TPM resealing efforts
    - Don't measure MokListTrusted to PCR7
    - SBAT level: shim,3
    - SBAT policy bumped to for grub,2 in previous and grub,3 in latest:
      SBAT policy: latest="shim,2\ngrub,3\n" previous="grub,2\n"
      Note that shim requirement was not bumped as shim,2 shims are not
      commonly available yet.
  * SECURITY FIX: Buffer overflow when loading crafted EFI images.
    - CVE-2022-28737
  * Rebase patches, only ubuntu-no-addend-vendor-dbx.patch remains
  * Import 20221103 Canonical vendor dbx.
    This vendor dbx revokes all certificates that have been used
    so far.
    - CN = Canonical Ltd. Secure Boot Signing
    - CN = Canonical Ltd. Secure Boot Signing (2017)
    - CN = Canonical Ltd. Secure Boot Signing (ESM 2018)
    - CN = Canonical Ltd. Secure Boot Signing (2019)
    - CN = Canonical Ltd. Secure Boot Signing (Ubuntu Core 2019)
    - CN = Canonical Ltd. Secure Boot Signing (2021 v1)
    - CN = Canonical Ltd. Secure Boot Signing (2021 v2)
    - CN = Canonical Ltd. Secure Boot Signing (2021 v3)
  * Build-Depend on libefivar-dev
  * debian/rules: Update COMMIT_ID

 -- Julian Andres Klode <email address hidden> Fri, 18 Nov 2022 16:00:39 +0100

Changed in shim (Ubuntu):
status: In Progress → Fix Released
Revision history for this message
Steve Langasek (vorlon) wrote : Please test proposed package

Hello dann, or anyone else affected,

Accepted shim into kinetic-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/shim/15.7-0ubuntu1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-kinetic to verification-done-kinetic. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-kinetic. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

Changed in shim (Ubuntu Kinetic):
status: New → Fix Committed
tags: added: verification-needed verification-needed-kinetic
Changed in shim (Ubuntu Jammy):
status: New → Fix Committed
tags: added: verification-needed-jammy
Revision history for this message
Steve Langasek (vorlon) wrote :

Hello dann, or anyone else affected,

Accepted shim into jammy-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/shim/15.7-0ubuntu1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-jammy to verification-done-jammy. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-jammy. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

Changed in shim (Ubuntu Focal):
status: New → Fix Committed
tags: added: verification-needed-focal
Revision history for this message
Steve Langasek (vorlon) wrote :

Hello dann, or anyone else affected,

Accepted shim into focal-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/shim/15.7-0ubuntu1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-focal to verification-done-focal. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-focal. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

Changed in shim (Ubuntu Bionic):
status: New → Fix Committed
tags: added: verification-needed-bionic
Revision history for this message
Steve Langasek (vorlon) wrote :

Hello dann, or anyone else affected,

Accepted shim into bionic-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/shim/15.7-0ubuntu1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-bionic to verification-done-bionic. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-bionic. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

Revision history for this message
dann frazier (dannf) wrote :

I rebooted a Bluefield 2 device running both jammy and focal in non-Secure Boot mode several times without any issue (this was the system/mode where we reproduced the issue before). These are the only releases supported on this hardware (linux-bluefield only exists there).

As part of verifying bug 2004208, I rebooted kinetic, jammy, and focal arm64 VMs in Secure Boot mode:

  https://bugs.launchpad.net/ubuntu/+source/shim-signed/+bug/2004208/comments/7

I've also rebooted a bionic VM in non-SecureBoot mode w/o any issue. No regressions were found.

dann frazier (dannf)
tags: added: verification-done verification-done-bionic verification-done-focal verification-done-jammy verification-done-kinetic
removed: verification-needed verification-needed-bionic verification-needed-focal verification-needed-jammy verification-needed-kinetic
Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package shim - 15.7-0ubuntu1

---------------
shim (15.7-0ubuntu1) kinetic; urgency=medium

  * New upstream version 15.7 (LP: #1996503), highlights:
    - Enable TDX measurements (LP: #1995852)
    - Flush the memory region from i-cache before execution (LP: #1987541)
    - Introspectable SBAT payload for TPM resealing efforts
    - Don't measure MokListTrusted to PCR7
    - SBAT level: shim,3
    - SBAT policy bumped to for grub,2 in previous and grub,3 in latest:
      SBAT policy: latest="shim,2\ngrub,3\n" previous="grub,2\n"
      Note that shim requirement was not bumped as shim,2 shims are not
      commonly available yet.
  * SECURITY FIX: Buffer overflow when loading crafted EFI images.
    - CVE-2022-28737
  * Rebase patches, only ubuntu-no-addend-vendor-dbx.patch remains
  * Import 20221103 Canonical vendor dbx.
    This vendor dbx revokes all certificates that have been used
    so far.
    - CN = Canonical Ltd. Secure Boot Signing
    - CN = Canonical Ltd. Secure Boot Signing (2017)
    - CN = Canonical Ltd. Secure Boot Signing (ESM 2018)
    - CN = Canonical Ltd. Secure Boot Signing (2019)
    - CN = Canonical Ltd. Secure Boot Signing (Ubuntu Core 2019)
    - CN = Canonical Ltd. Secure Boot Signing (2021 v1)
    - CN = Canonical Ltd. Secure Boot Signing (2021 v2)
    - CN = Canonical Ltd. Secure Boot Signing (2021 v3)
  * Build-Depend on libefivar-dev
  * debian/rules: Update COMMIT_ID

 -- Julian Andres Klode <email address hidden> Fri, 18 Nov 2022 16:00:39 +0100

Changed in shim (Ubuntu Kinetic):
status: Fix Committed → Fix Released
Revision history for this message
Łukasz Zemczak (sil2100) wrote : Update Released

The verification of the Stable Release Update for shim has completed successfully and the package is now being released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package shim - 15.7-0ubuntu1

---------------
shim (15.7-0ubuntu1) kinetic; urgency=medium

  * New upstream version 15.7 (LP: #1996503), highlights:
    - Enable TDX measurements (LP: #1995852)
    - Flush the memory region from i-cache before execution (LP: #1987541)
    - Introspectable SBAT payload for TPM resealing efforts
    - Don't measure MokListTrusted to PCR7
    - SBAT level: shim,3
    - SBAT policy bumped to for grub,2 in previous and grub,3 in latest:
      SBAT policy: latest="shim,2\ngrub,3\n" previous="grub,2\n"
      Note that shim requirement was not bumped as shim,2 shims are not
      commonly available yet.
  * SECURITY FIX: Buffer overflow when loading crafted EFI images.
    - CVE-2022-28737
  * Rebase patches, only ubuntu-no-addend-vendor-dbx.patch remains
  * Import 20221103 Canonical vendor dbx.
    This vendor dbx revokes all certificates that have been used
    so far.
    - CN = Canonical Ltd. Secure Boot Signing
    - CN = Canonical Ltd. Secure Boot Signing (2017)
    - CN = Canonical Ltd. Secure Boot Signing (ESM 2018)
    - CN = Canonical Ltd. Secure Boot Signing (2019)
    - CN = Canonical Ltd. Secure Boot Signing (Ubuntu Core 2019)
    - CN = Canonical Ltd. Secure Boot Signing (2021 v1)
    - CN = Canonical Ltd. Secure Boot Signing (2021 v2)
    - CN = Canonical Ltd. Secure Boot Signing (2021 v3)
  * Build-Depend on libefivar-dev
  * debian/rules: Update COMMIT_ID

 -- Julian Andres Klode <email address hidden> Fri, 18 Nov 2022 16:00:39 +0100

Changed in shim (Ubuntu Jammy):
status: Fix Committed → Fix Released
Launchpad Janitor (janitor)
Changed in shim (Ubuntu Focal):
status: Fix Committed → Fix Released
dann frazier (dannf)
Changed in shim (Ubuntu Focal):
status: Fix Released → Fix Committed
Launchpad Janitor (janitor)
Changed in shim (Ubuntu Focal):
status: Fix Committed → Fix Released
Launchpad Janitor (janitor)
Changed in shim (Ubuntu Bionic):
status: Fix Committed → Fix Released
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