On Wed, Sep 20, 2017 at 10:13:35AM +0200, Thiebaud Weksteen wrote:
> With TPM 1.2, the ACPI table ("TCPA") has two fields to recover the Event
> Log Area (LAML and LASA). These logs are useful to understand and rebuild
> the final values of PCRs.
>
> With TPM 2.0, the ACPI table ("TPM2") does not contain these fields
> anymore. The recommended method is now to call the GetEventLog EFI
> protocol before ExitBootServices.
>
> Implement this method within the EFI stub and create a copy of the logs
> for the TPM device using a Linux-specific EFI configuration table
> (LINUX_EFI_TPM_EVENT_LOG). This will create
> /sys/kernel/security/tpm0/binary_bios_measurements for TPM 2.0 devices
> (similarly to the current behaviour for TPM 1.2 devices).
>
> Two formats for the log entries exist: TPM 1.2 (SHA1) and TPM 2.0 (Crypto
> Agile). This patch set only retrieves the first type of logs. The second
> type will be implemented in a subsequent patch set.
>
> According to the specifications[1], once GetEventLog has been called,
> future events shall be stored in a separate EFI configuration table
> (EFI_TCG2_FINAL_EVENTS_TABLE). Events stored in this table are not
> processed in this patch set as they are stored in the Crypto Agile format.
> These could eventually be merged with the new table for a unified view
> of the logs from userspace.
>
> [1] TCG EFI Protocol Specification, Revision 00.13, March 30, 2016
>
> https://trustedcomputinggroup.org/wp-content/uploads/EFI-Protocol-Specification-rev13-160330final.pdf
>
> ---
>
> Patchset Changelog:
>
> Version 3:
> - Move event log providers (acpi and of) to tpm_eventlog_*.c
> - Move efi changes from PATCH 3 to PATCH 2
> - Change return value of tpm_read_log_acpi and tpm_read_log_of
> - Change iounmap to memunmap calls
> - Use log_tbl as variable name for consistency
> - Fix kbuild failures
>
> Version 2:
> - Move tpm_eventlog.h to top include directory, add commit for this.
> - Use EFI_LOADER_DATA to store the configuration table
> - Whitespace and new lines fixes
>
> Thiebaud Weksteen (5):
> tpm: move tpm_eventlog.h outside of drivers folder
> tpm: rename event log provider files
> tpm: add event log format version
> efi: call get_event_log before ExitBootServices
> tpm: parse TPM event logs based on EFI table
>
> arch/x86/boot/compressed/eboot.c | 1 +
> drivers/char/tpm/Makefile | 5 +-
> drivers/char/tpm/tpm-chip.c| 3 +-
> drivers/char/tpm/tpm-interface.c | 2 +-
> drivers/char/tpm/tpm.h | 35 --
> drivers/char/tpm/tpm1_eventlog.c | 13 +++-
> drivers/char/tpm/tpm2_eventlog.c | 2 +-
> .../char/tpm/{tpm_acpi.c => tpm_eventlog_acpi.c} | 4 +-
> drivers/char/tpm/tpm_eventlog_efi.c| 66 ++
> drivers/char/tpm/{tpm_of.c => tpm_eventlog_of.c} | 6 +-
> drivers/firmware/efi/Makefile | 2 +-
> drivers/firmware/efi/efi.c | 4 ++
> drivers/firmware/efi/libstub/Makefile | 3 +-
> drivers/firmware/efi/libstub/tpm.c | 81
> ++
> drivers/firmware/efi/tpm.c | 40 +++
> include/linux/efi.h| 46
> {drivers/char/tpm => include/linux}/tpm_eventlog.h | 35 +++---
> 17 files changed, 304 insertions(+), 44 deletions(-)
> rename drivers/char/tpm/{tpm_acpi.c => tpm_eventlog_acpi.c} (97%)
> create mode 100644 drivers/char/tpm/tpm_eventlog_efi.c
> rename drivers/char/tpm/{tpm_of.c => tpm_eventlog_of.c} (93%)
> create mode 100644 drivers/firmware/efi/tpm.c
> rename {drivers/char/tpm => include/linux}/tpm_eventlog.h (77%)
>
> --
> 2.14.1.821.g8fa685d3b7-goog
>
Thank you. I'll have to postpone testing this at some point next week.
/Jarkko
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