EBBR Notes 2023.03.13

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Vincent Stehlé edited this page Mar 13, 2023 · 1 revision

Attendees

Ivan T. Ivanov (Suse)
Ilias Apalodimas (Linaro)
Etienne Carrière (STMicroelectronics)
Vincent Stehlé (Arm)

Agenda

Review pull requests:
- Pull request #102: File Format For Storing EFI Variables (Heinrich)
- Pull request #104: Relax monotonic counter nonvolatility
- Pull request #105: Recommend the firmware update protocol

Notes

Ilias: will rework pages permissions if time permits
- U-Boot maps everything RWX
- UEFI 2.10 allows mem attributes
- Ivan: for OS, world starts at GRUB
Pull request #102: File Format For Storing EFI Variables (Heinrich)
- Ilias: seems to get some traction, people seem happy
- Ivan: store file on ESP? Ilias: no concurrent access
- Should pass the file location to the OS in the Devicetree (use fstab UUID?)
Pull request #104: Relax monotonic counter nonvolatility
- Ilias: monotonic counter high part could be used for security
- We could allow non-volatility in EBBR or even make it optional
- We could fix U-Boot
- Could we return device error? Would that break the OS boot
- We need some more time to reflect on this one
- We need hardware backing for this one
- Storing a monotonic counter in a file would allow rollback
- Leverage StMM?
  - U-Boot issues smc to call op-tee, op-tee uses FF-A to StMM
  - mm-communicate; could leverage for monotonic counter
  - Ilias: mm-communicate should be non-interruptible
Pull request #105: Recommend the firmware update protocol
- Ilias: should we require? Need to look at kernel, too
- Let's postpone to next call

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