[PATCH v3 4/4] tools: binman: fit: add tests for signing with an OpenSSL engine

[Quentin Schulz]

Hi Tom,

On 12/2/25 9:14 PM, Tom Rini wrote:
> On Tue, Dec 02, 2025 at 08:06:02PM +0000, Simon Glass wrote:
>> Hi Quentin,
>>
>> On Wed, 26 Nov 2025 at 04:44, Quentin Schulz <quentin.schulz at cherry.de> wrote:
>>>
>>> Hi Simon,
>>>
>>> On 11/25/25 11:15 PM, Simon Glass wrote:
>>>> Hi Quentin,
>>>>
>>>> On Fri, 21 Nov 2025 at 10:15, Quentin Schulz <foss+uboot at 0leil.net> wrote:
>>>>>
>>>>> From: Quentin Schulz <quentin.schulz at cherry.de>
>>>>>
>>>>> This adds a test that signs a FIT and verifies the signature with
>>>>> fit_check_sign.
>>>>>
>>>>> OpenSSL engines are typically for signing with external HW so it's not
>>>>> that straight-forward to simulate.
>>>>>
>>>>> For a simple RSA OpenSSL engine, a dummy engine with a hardcoded RSA
>>>>> 4096 private key is made available. It can be selected by setting the
>>>>> OpenSSL engine argument to dummy-rsa-engine. This can only be done if
>>>>> the engine is detected by OpenSSL, which works by setting the
>>>>> OPENSSL_ENGINES environment variable. I have no clue if dummy-rsa-engine
>>>>> is properly implementing what is expected from an RSA engine, but it
>>>>> seems to be enough for testing.
>>>>>
>>>>> For a simple PKCS11 engine, SoftHSMv2 is used, which allows to do PKCS11
>>>>> without specific hardware. The keypairs and tokens are generated on the
>>>>> fly. The "prod" token is generated with a different PIN (1234 instead of
>>>>> 1111) to also test MKIMAGE_SIGN_PIN env variable while we're at it.
>>>>>
>>>>> Binman will not mess with the local SoftHSMv2 setup as it will only use
>>>>> tokens from a per-test temporary directory enforced via the temporary
>>>>> configuration file set via SOFTHSM2_CONF env variable in the tests. The
>>>>> files created in the input dir should NOT be named the same as it is
>>>>> shared between all tests in the same process (which is all tests when
>>>>> running binman with -P 1 or with -T).
>>>>>
>>>>> Once signed, it's checked with fit_check_sign with the associated
>>>>> certificate.
>>>>>
>>>>> Finally, a new softhsm2_util bintool is added so that we can initialize
>>>>> the token and import keypairs. On Debian, the package also brings
>>>>> libsofthsm2 which is required for OpenSSL to interact with SoftHSMv2. It
>>>>> is not the only package required though, as it also needs p11-kit and
>>>>> libengine-pkcs11-openssl (the latter bringing the former). We can detect
>>>>> if it's properly installed by running openssl engine dynamic -c pkcs11.
>>>>> If that fails, we simply skip the test.
>>>>> The package is installed in the CI container by default.
>>>>>
>>>>> Signed-off-by: Quentin Schulz <quentin.schulz at cherry.de>
>>>>> ---
>>>>>    tools/binman/btool/softhsm2_util.py                |  21 ++
>>>>>    tools/binman/ftest.py                              | 223 +++++++++++++++++++++
>>>>>    tools/binman/test/340_dummy-rsa4096.crt            |  31 +++
>>>>>    tools/binman/test/340_fit_signature_engine.dts     |  99 +++++++++
>>>>>    .../test/340_fit_signature_engine_encrypt.dts      | 100 +++++++++
>>>>>    .../test/340_fit_signature_engine_pkcs11.dts       |  99 +++++++++
>>>>>    .../340_fit_signature_engine_pkcs11_object.dts     | 100 +++++++++
>>>>>    tools/binman/test/340_openssl.conf                 |  10 +
>>>>>    tools/binman/test/340_softhsm2.conf                |  16 ++
>>>>>    tools/binman/test/Makefile                         |   6 +-
>>>>>    tools/binman/test/dummy-rsa-engine.c               | 149 ++++++++++++++
>>>>>    11 files changed, 853 insertions(+), 1 deletion(-)
>>>>
>>>> Not sure of the changes from last time, but I assume the test coverage
>>>> is finished.
>>>>
>>>
>>> They are listed in the cover letter in the Changes section.
>>>
>>> $ b4 diff -v 2 3 --
>>> https://lore.kernel.org/u-boot/20251121-binman-engine-v3-0-b80180aaa783@cherry.de/T/\#t
>>>
>>> will show you the git-range-diff between both versions for a given commit.
>>
>> I normally review just in email (often on a Chromebook) so I don't
>> have that. It is also an extra step and I don't know where your log
>> argument comes from. It would be better to put the change log in the
>> patch as well.
> 
> The cover letter is just an email. Perhaps a handy tips bit of
> documentation (and external ref to the general b4 docs) would be
> helpful, especially since b4 is a common and widely used tool these
> days.
> 

I can do that, what do you have in mind? What should we add to the docs?

Cheers,
Quentin