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EBBR Notes 2023.03.27

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Vincent Stehlé edited this page Mar 28, 2023 · 1 revision

Attendees

  • Heinrich Schuchardt (Canonical)
  • Ilias Apalodimas (Linaro)
  • Etienne Carrière (STMicroelectronics)
  • Vincent Stehlé (Arm)

Agenda

Notes

  • Ilias: we can query RPMB support at runtime and fallback to file-based when not found.
  • Pull request #102: File Format For Storing EFI Variables (Heinrich)
    • chosen path to the file: cannot rely on mount point. Assume in ESP and mention only relative path. More than one ESP are allowed. GUID is better.
    • Don't forget to add suggested-by when merging.
    • Chosen node has further specification in Devicetree specification; ping Rob H.
    • Proposed format: UUID=1234:45678,/ubootefi.var
    • Merge patch as-is and add a note.
  • Pull request #104: Make monotonic counter optional (was: Relax monotonic counter nonvolatility)
    • Linaro will work on updating U-Boot one way or another.
    • Heinrich: high monotonic count, daylight saving flag and timezone offset could be backed by UEFI variables. Etienne: user could modify. Could be marked read-only to avoid user update. Ilias: ok for DST and offset but monotonic could be deleted, could cause issues.
    • Etienne: do we have an available monotonic counter in the RPMB? Heinrich: we have 1/2 MB; let's find a free byte there. Add a new function to StMM?
    • Merge patch; acked-by from Ilias.
    • Then post a patch with a note about security: if high part cannot survive reset do not implement at all.
  • Pull request #105: Recommend the firmware update protocol
    • Point at 23.4.4 Mapping Firmware Management Protocol Descriptors to ESRT Entries
  • Ilias: Linux RPMB patches are in v3 or v4.
  • When supplementing firmware with generic ops for efivars, what should fwts test in the end? The actual firmware interface, not capable of SetVariable() at runtime, or the resulting interface?
    • Ilias: fwts should be smarter about this case
    • Heinrich: the kernel already modifies the tables

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