[PATCH v5 00/16] efi_loader: add secure boot support

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

On Sun, Feb 23, 2020 at 12:53:16PM +0100, Heinrich Schuchardt wrote:
> On 1/28/20 9:25 AM, AKASHI Takahiro wrote:
> > # Documentation for UEFI secure boot on U-Boot will be submitted in
> > # a separate patch in near future.
> > 
> > One of major missing features in current UEFI implementation is "secure boot."
> > The ultimate goal of my attempt is to implement image authentication based
> > on signature and provide UEFI secure boot support which would be fully
> > compliant with UEFI specification, section 32[1].
> > (The code was originally developed by Patrick Wildt.)
> > 
> > Please note, however, this patch doesn't work on its own; there are
> > a couple of functional dependencies[2] and [3], that I have submitted
> > before. For complete workable patch set, see my repository[4],
> > which also contains experimental timestamp-based revocation suuport.
> > 
> > My "non-volatile" support[5], which is under discussion, is not mandatory
> > and so not included here, but this inevitably implies that, for example,
> > signature database variables, like db and dbx, won't be persistent unless
> > you explicitly run "env save" command.
> > Anyhow, Linaro is also working on implementing real "secure storage"
> > solution based on TF-A and OP-TEE.
> 
> In the patch series I am missing a patch providing the documentation
> explaining how to set up secure boot with U-Boot. doc/uefi/uefi.rst
> would be a good place for it.

See:
https://lists.denx.de/pipermail/u-boot/2020-February/399446.html

I posted this patch as a separate one because I believe
that we can discuss separately from the code.

-Takahiro Akashi


> I guess the description should include:
> 
> - which certificates have to be created and how to generate these
> - which variables have to be initialized with which values
> - how the images can be signed
> 
> Best regards
> 
> Heinrich
> 
> > 
> > 
> > Supported features:
> > * image authentication based on db and dbx
> > * supported signature types are
> >      EFI_CERT_SHA256_GUID (SHA256 digest for unsigned images)
> >      EFI_CERT_X509_GUID (x509 certificate for signed images)
> > * SecureBoot/SignatureSupport variables
> > * SetupMode and user mode
> > * variable authentication based on PK and KEK
> >      EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS
> > * basic pytest test cases
> > 
> > Unsupported features: (marked as TODO in most cases in the source code,
> > 			and won't be included in this series)
> > * hash algorithms other than SHA256
> > * dbt: timestamp(RFC6131)-based certificate revocation
> > * dbr: OS recovery
> > * xxxDefault: default values for signature stores
> > * transition to AuditMode and DeployedMode
> > * recording rejected images in EFI_IMAGE_EXECUTION_INFO_TABLE
> > * verification "policy", in particular, check against signature's owner
> > * private authenticated variables
> > * variable authentication with EFI_VARIABLE_ENHANCED_AUTHENTICATED_ACCESS
> > * real secure storage support, including hardware-specific PK (Platform Key)
> >    installation
> > 
> > TODO's other than "Unsupported features": (won't be included in this series)
> > * fail recovery, in particular, in modifying authenticated variables
> > * support read-only attributes of well-defined global variables
> >    in particular, "SignatureSupport"
> > * Extensive test suite (or more test cases) to confirm compatibility
> >    with EDK2
> > 	=> I requested EDK SCT community to add tests[6].
> > 
> > Test:
> > * My pytest, included in this patch set, passed.
> > * efi_selftest passed. (At least no regression.)
> > * Travis CI tests have passed.
> > 
> > Known issues:
> > * efitools is used in pytest, and its version must be v1.5.2 or later.
> >    (Solution: You can define EFITOOLS_PATH in defs.py for your own efitools.)
> > 
> > 
> > Hints about how to use:
> > (Please see other documents, or my pytest scripts, for details.)
> > * You can create your own certificates with openssl.
> > * You can sign your application with sbsign (on Ubuntu).
> > * You can create raw data for signature database with efitools, and
> >    install/manage authenticated variables with "env -set -e" command
> >    or efitools' "UpdateVars.efi" application.
> > 
> > 
> > [1] https://uefi.org/sites/default/files/resources/UEFI_Spec_2_8_final.pdf
> > [2] https://lists.denx.de/pipermail/u-boot/2019-November/390127.html
> >      (import x509/pkcs7 parsers from linux)
> > [3] https://lists.denx.de/pipermail/u-boot/2020-January/398057.html
> >      (extend rsa_verify() for UEFI secure boot)
> > [4] http://git.linaro.org/people/takahiro.akashi/u-boot.git/ efi/secboot
> > [5] https://lists.denx.de/pipermail/u-boot/2019-September/382835.html
> >      (non-volatile variables support)
> > [6] https://bugzilla.tianocore.org/show_bug.cgi?id=2230
> > 
> > 
> > Changes in v5 (Jan 28, 2020)
> > * rebased to pre-v2020.04-rc1 (fixed some merge conflicts)
> > * remove already-merged commits (v4's patch#1)
> > * fix a compile error caused by gcc 9.x (patch#4)
> > * return SECURITY_VIOLATION instead of ACCESS_DENIED if authentication fails
> >    (patch#7)
> > * use qsort() for section sorting (patch#7)
> > * add "efidebug test" sub-command (patch#11)
> > * add efi_start_image(SECURITY_VIOLATION) test (patch#14)
> > 
> > Changes in v4 (Dec 18, 2019)
> > * adjust EFI_SECURE_BOOT dependencies due to a change of RSA extension patch v5
> >    (patch#2)
> > * change "imply" to "select" against kconfig dependencies (patch#2)
> > * otherwise, no functional changes
> > 
> > Changes in v3 (Dec 9, 2019)
> > * allow for arbitrary number of regions in efi_image_region_add()
> >    (patch#3, #5 and #8)
> > * remove a redundant check in a while loop at efi_sigstore_free() (patch#4)
> > 
> > Changes in v2 (Nov 26, 2019)
> > * rebased to v2020.01-rc3
> > * rename IMAGE_DIRECTORY_ENTRY_CERTTABLE to IMAGE_DIRECTORY_ENTRY_SECURITY
> >    (patch#1,#9)
> > * add comments (patch#1)
> > * drop v1's patch#2 as it is no longer necessary
> > * drop v1's patch#3 as other "SECURE_BOOT" architectures have renamed
> >    this option and no longer use it
> > * add structure descriptions (patch#3)
> > * rework hash calculation code in efi_signature_verify() and remove
> >    an odd constant, WinIndrectSha256 (patch#3)
> > * move travis.yml changes to a separate patch (patch#12, #16)
> > * yield_fixture() -> fixture() (patch#12)
> > * call console.restart_uboot() at every test case (13,#14)
> > * add patch#15; enable UEFI-related configurations by default on sandbox
> > * add patch#16; modify Travis CI environment to run UEFI secure boot test
> > 
> > Changes in v1 (Nov 13, 2019)
> > * rebased to v2020.01-rc
> > * remove already-merged patches
> > * re-work the patch set for easier reviews, including
> >    - move a config definition patch forward (patch#4)
> >    - refactor/rename verification functions (patch#5/#10)
> >    - split signature database parser as a separate patch (patch#6)
> >    - split secure state transition code as a separate patch (patch#8)
> >    - move most part of init_secure_boot() into init_variables() (patch#8)
> >    - split test environment setup from test patches (patch#14)
> > * add function descriptions (patch#5-#11)
> > * make sure the section list is sorted in ascending order in hash
> >    calculation of PE image (patch#10)
> > * add a new "-at" (authenticated access) option to "env -e" (patch#13)
> > * list required host packages, in particular udisks2, in pytest
> >    (patch#14)
> > * modify conftest.py to run under python3 (patch#14)
> > * use a partition on a disk instead of a whole disk without partition
> >    table (patch#14)
> > * reduce dependency on efitools, yet relying on its host tools (patch#14)
> > * modify pytests to catch up wth latest changes of "env -e" syntax
> >    (patch#15,#16)
> > 
> > RFC (Sept 18, 2019)
> > 
> > AKASHI Takahiro (16):
> >    efi_loader: add CONFIG_EFI_SECURE_BOOT config option
> >    efi_loader: add signature verification functions
> >    efi_loader: add signature database parser
> >    efi_loader: variable: support variable authentication
> >    efi_loader: variable: add secure boot state transition
> >    efi_loader: variable: add VendorKeys variable
> >    efi_loader: image_loader: support image authentication
> >    efi_loader: set up secure boot
> >    cmd: env: use appropriate guid for authenticated UEFI variable
> >    cmd: env: add "-at" option to "env set -e" command
> >    cmd: efidebug: add "test bootmgr" sub-command
> >    efi_loader, pytest: set up secure boot environment
> >    efi_loader, pytest: add UEFI secure boot tests (authenticated
> >      variables)
> >    efi_loader, pytest: add UEFI secure boot tests (image)
> >    sandbox: add extra configurations for UEFI and related tests
> >    travis: add packages for UEFI secure boot test
> > 
> >   .travis.yml                                   |  11 +-
> >   cmd/efidebug.c                                |  78 +-
> >   cmd/nvedit.c                                  |   5 +-
> >   cmd/nvedit_efi.c                              |  23 +-
> >   configs/sandbox64_defconfig                   |   3 +
> >   configs/sandbox_defconfig                     |   3 +
> >   include/efi_api.h                             |  87 ++
> >   include/efi_loader.h                          |  91 +-
> >   lib/efi_loader/Kconfig                        |  18 +
> >   lib/efi_loader/Makefile                       |   1 +
> >   lib/efi_loader/efi_boottime.c                 |  10 +-
> >   lib/efi_loader/efi_image_loader.c             | 460 ++++++++-
> >   lib/efi_loader/efi_setup.c                    |  38 +
> >   lib/efi_loader/efi_signature.c                | 809 +++++++++++++++
> >   lib/efi_loader/efi_variable.c                 | 951 ++++++++++++++++--
> >   test/py/README.md                             |   8 +
> >   test/py/tests/test_efi_secboot/conftest.py    | 151 +++
> >   test/py/tests/test_efi_secboot/defs.py        |  21 +
> >   .../py/tests/test_efi_secboot/test_authvar.py | 282 ++++++
> >   test/py/tests/test_efi_secboot/test_signed.py | 117 +++
> >   .../tests/test_efi_secboot/test_unsigned.py   | 121 +++
> >   21 files changed, 3157 insertions(+), 131 deletions(-)
> >   create mode 100644 lib/efi_loader/efi_signature.c
> >   create mode 100644 test/py/tests/test_efi_secboot/conftest.py
> >   create mode 100644 test/py/tests/test_efi_secboot/defs.py
> >   create mode 100644 test/py/tests/test_efi_secboot/test_authvar.py
> >   create mode 100644 test/py/tests/test_efi_secboot/test_signed.py
> >   create mode 100644 test/py/tests/test_efi_secboot/test_unsigned.py
> > 
>