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

[Tom Rini]

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.

-- 
Tom
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