vboot: extend BOOT_MODE_PCR to SHA256 bank on TPM2

With the support of various algorithms and banks in tlcl_extend(),
digest_algo parameter of tpm_extend_pcr() started defining the target
PCR bank in TPM2 case.

The OS expects coreboot to extend the SHA256 bank of BOOT_MODE_PCR.
The value that the OS expects coreboot to extend into BOOT_MODE_PCR
is the SHA1 digest of mode bits extended to the length of SHA256 digest
by appending zero bytes.

Thus the correct value for digest_algo passed into tpm_extend_pcr() for
BOOT_MODE_PCR is TPM_ALG_SHA256.

This didn't matter until adding the support for multiple digest introduced
by patches like https://review.coreboot.org/c/coreboot/+/33252, as
tlcl_extend always used SHA256 bank before.

Change-Id: I834fec24023cd10344cc359117f00fc80c61b80c
Signed-off-by: Andrey Pronin <apronin@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35476
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
1 file changed
tree: 5a6f119ff12abe30956549b25ab5abb95c3365a2
  1. 3rdparty/
  2. configs/
  3. Documentation/
  4. payloads/
  5. src/
  6. util/
  7. .checkpatch.conf
  8. .clang-format
  9. .editorconfig
  10. .gitignore
  11. .gitmodules
  12. .gitreview
  13. AUTHORS
  14. COPYING
  15. gnat.adc
  16. MAINTAINERS
  17. Makefile
  18. Makefile.inc
  19. README.md
  20. toolchain.inc
README.md

coreboot README

coreboot is a Free Software project aimed at replacing the proprietary BIOS (firmware) found in most computers. coreboot performs a little bit of hardware initialization and then executes additional boot logic, called a payload.

With the separation of hardware initialization and later boot logic, coreboot can scale from specialized applications that run directly firmware, run operating systems in flash, load custom bootloaders, or implement firmware standards, like PC BIOS services or UEFI. This allows for systems to only include the features necessary in the target application, reducing the amount of code and flash space required.

coreboot was formerly known as LinuxBIOS.

Payloads

After the basic initialization of the hardware has been performed, any desired "payload" can be started by coreboot.

See https://www.coreboot.org/Payloads for a list of supported payloads.

Supported Hardware

coreboot supports a wide range of chipsets, devices, and mainboards.

For details please consult:

Build Requirements

  • make
  • gcc / g++ Because Linux distribution compilers tend to use lots of patches. coreboot does lots of "unusual" things in its build system, some of which break due to those patches, sometimes by gcc aborting, sometimes - and that's worse - by generating broken object code. Two options: use our toolchain (eg. make crosstools-i386) or enable the ANY_TOOLCHAIN Kconfig option if you're feeling lucky (no support in this case).
  • iasl (for targets with ACPI support)
  • pkg-config
  • libssl-dev (openssl)

Optional:

  • doxygen (for generating/viewing documentation)
  • gdb (for better debugging facilities on some targets)
  • ncurses (for make menuconfig and make nconfig)
  • flex and bison (for regenerating parsers)

Building coreboot

Please consult https://www.coreboot.org/Build_HOWTO for details.

Testing coreboot Without Modifying Your Hardware

If you want to test coreboot without any risks before you really decide to use it on your hardware, you can use the QEMU system emulator to run coreboot virtually in QEMU.

Please see https://www.coreboot.org/QEMU for details.

Website and Mailing List

Further details on the project, a FAQ, many HOWTOs, news, development guidelines and more can be found on the coreboot website:

https://www.coreboot.org

You can contact us directly on the coreboot mailing list:

https://www.coreboot.org/Mailinglist

Copyright and License

The copyright on coreboot is owned by quite a large number of individual developers and companies. Please check the individual source files for details.

coreboot is licensed under the terms of the GNU General Public License (GPL). Some files are licensed under the "GPL (version 2, or any later version)", and some files are licensed under the "GPL, version 2". For some parts, which were derived from other projects, other (GPL-compatible) licenses may apply. Please check the individual source files for details.

This makes the resulting coreboot images licensed under the GPL, version 2.