Re: [docs] [PATCH] security-manual: Add information about how security is handled in builds

[Richard Purdie <richard.purdie@linuxfoundation.org>]

On Tue, 2026-08-11 at 10:01 +0200, Antonin Godard wrote:
> On Fri Aug 7, 2026 at 6:43 PM CEST, Richard Purdie via lists.yoctoproject.org wrote:
> > We have no information about how security is handled within the builds
> > themselves. Start to document this.
> > 
> > Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
> > ---
> >  .../security-manual/build-security.rst        | 41 +++++++++++++++++++
> >  documentation/security-manual/index.rst       |  1 +
> >  2 files changed, 42 insertions(+)
> >  create mode 100644 documentation/security-manual/build-security.rst
> > 
> > diff --git a/documentation/security-manual/build-security.rst b/documentation/security-manual/build-security.rst
> > new file mode 100644
> > index 000000000..5f15d5f64
> > --- /dev/null
> > +++ b/documentation/security-manual/build-security.rst
> > @@ -0,0 +1,41 @@
> > +.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
> > +
> > +**************
> > +Build Security
> 
> I suggest renaming it to "OpenEmbedded Build System Security", as "Build" alone
> could be interpreted in many different ways, including builds for specific
> software components, etc.

Perhaps "Build Process Security"? I think build system isn't quit the
right thing here.

> 
> > +**************
> > +
> > +OpenEmbedded is used to run the builds and careful consideration has gone into
> 
> When you say "OpenEmbedded" I guess you mean the community? Or the build system?
> 
> We have a :term:`OpenEmbedded Build System` that could be used here if relevant.

That seems like the right thing to use.

> > +how it does this with the aim of being both secure and reproducible. Like any
> > +system, it does need to be used carefully and in keeping with the design for
> > +that to be true. Users of the system should consider that:
> > +
> > +-  The builds generally aim for any input into the build process being verified in
> > +   some form. For source code tarballs, these would have a checksum. Git source
> > +   trees would have a specific git revision. Metadata would also usually be
> > +   under source control and also have revisions.
> 
> Add a link to our fetching documentation here?
> 
> """
> See the :doc:`bitbake:bitbake-user-manual/bitbake-user-manual-fetching` section
> of the BitBake User Manual for more information.
> """

Sure, I intended this as a first pass and figured it might need some
markup/tweaking. Sorry for the spelling :/.

> 
> > +
> > +-  Some elements that can influence the build are not verified. It is assumed
> > +   that the operating system running the system is secure and of a known setup and
> > +   version. The system goes to signififant lengths to isolate against host
> > +   contamination of the output but it is certainly possible, especially malicously.
> 
> typo: maliciously
> 
> Link to our supported distros here?
> 
> """
> See the :ref:`system-requirements-supported-distros` section of the Yocto
> Project Reference Manual for more information on supported host distributions.
> """
> 
> > +
> > +-  The builds assume DL_DIR is a safe location. Once things enter that location
> 
> s/DL_DIR/:term:`DL_DIR`/
> 
> > +   there are not repeatedly re-verified. A user could edit the git trees or
> > +   tarballs there in ways the build might not detect.
> 
> I guess this will be better detailed with
> https://bugzilla.yoctoproject.org/show_bug.cgi?id=16102. Maybe the documentation
> coming from this bug should be linked here then.

This text was intended to help close 16102 :/. We've not managed to get
anyone else to provide such information. Certainly if any more is
forthcoming, this would be the place to add it. I did want to document
something before we close that bug though.

Cheers,

Richard