1.. SPDX-License-Identifier: CC-BY-SA-2.0-UK 2 3Creating a Software Bill of Materials 4************************************* 5 6Once you are able to build an image for your project, once the licenses for 7each software component are all identified (see 8":ref:`dev-manual/licenses:working with licenses`") and once vulnerability 9fixes are applied (see ":ref:`dev-manual/vulnerabilities:checking 10for vulnerabilities`"), the OpenEmbedded build system can generate 11a description of all the components you used, their licenses, their dependencies, 12their sources, the changes that were applied to them and the known 13vulnerabilities that were fixed. 14 15This description is generated in the form of a *Software Bill of Materials* 16(:term:`SBOM`), using the :term:`SPDX` standard. 17 18When you release software, this is the most standard way to provide information 19about the Software Supply Chain of your software image and SDK. The 20:term:`SBOM` tooling is often used to ensure open source license compliance by 21providing the license texts used in the product which legal departments and end 22users can read in standardized format. 23 24:term:`SBOM` information is also critical to performing vulnerability exposure 25assessments, as all the components used in the Software Supply Chain are listed. 26 27The OpenEmbedded build system doesn't generate such information by default. 28To make this happen, you must inherit the 29:ref:`ref-classes-create-spdx` class from a configuration file:: 30 31 INHERIT += "create-spdx" 32 33Upon building an image, you will then get: 34 35- :term:`SPDX` output in JSON format as an ``IMAGE-MACHINE.spdx.json`` file in 36 ``tmp/deploy/images/MACHINE/`` inside the :term:`Build Directory`. 37 38- This toplevel file is accompanied by an ``IMAGE-MACHINE.spdx.index.json`` 39 containing an index of JSON :term:`SPDX` files for individual recipes. 40 41- The compressed archive ``IMAGE-MACHINE.spdx.tar.zst`` contains the index 42 and the files for the single recipes. 43 44The :ref:`ref-classes-create-spdx` class offers options to include 45more information in the output :term:`SPDX` data: 46 47- Make the json files more human readable by setting (:term:`SPDX_PRETTY`). 48 49- Add compressed archives of the files in the generated target packages by 50 setting (:term:`SPDX_ARCHIVE_PACKAGED`). 51 52- Add a description of the source files used to generate host tools and target 53 packages (:term:`SPDX_INCLUDE_SOURCES`) 54 55- Add archives of these source files themselves (:term:`SPDX_ARCHIVE_SOURCES`). 56 57Though the toplevel :term:`SPDX` output is available in 58``tmp/deploy/images/MACHINE/`` inside the :term:`Build Directory`, ancillary 59generated files are available in ``tmp/deploy/spdx/MACHINE`` too, such as: 60 61- The individual :term:`SPDX` JSON files in the ``IMAGE-MACHINE.spdx.tar.zst`` 62 archive. 63 64- Compressed archives of the files in the generated target packages, 65 in ``packages/packagename.tar.zst`` (when :term:`SPDX_ARCHIVE_PACKAGED` 66 is set). 67 68- Compressed archives of the source files used to build the host tools 69 and the target packages in ``recipes/recipe-packagename.tar.zst`` 70 (when :term:`SPDX_ARCHIVE_SOURCES` is set). Those are needed to fulfill 71 "source code access" license requirements. 72 73See also the :term:`SPDX_CUSTOM_ANNOTATION_VARS` variable which allows 74to associate custom notes to a recipe. 75See the `tools page <https://spdx.dev/resources/tools/>`__ on the :term:`SPDX` 76project website for a list of tools to consume and transform the :term:`SPDX` 77data generated by the OpenEmbedded build system. 78 79See also Joshua Watt's presentations 80`Automated SBoM generation with OpenEmbedded and the Yocto Project <https://youtu.be/Q5UQUM6zxVU>`__ 81at FOSDEM 2023 and 82`SPDX in the Yocto Project <https://fosdem.org/2024/schedule/event/fosdem-2024-3318-spdx-in-the-yocto-project/>`__ 83at FOSDEM 2024. 84