License audit tooling for Fedora packages

This page describes the tools used in standard practice to audit licensing of packages in the Fedora Linux distribution.

Packaging tools

These tools are used for evaluating the state of licensing in Fedora Linux packages. These use the Fedora License Data as a source for valid licenses.


rpmlint is the standard tool used for evaluating Fedora Linux packages for well-known issues for packagers to fix. In the context of licensing, rpmlint evaluates the License: field in the spec file and ensures the values comply with the known standard of allowed licenses.

This is packaged in Fedora Linux as rpmlint.


rpminspect is the tool used to evaluate Fedora Linux packages for policy compliance, differences as compared to previous builds, and common packaging errors as they are built in the Fedora Build System. In the context of licensing, rpminspect evaluates the License: field in RPMs and ensures the values comply with the known standard of allowed licenses.

This is packaged in Fedora Linux as rpminspect. To use it, you need both rpminspect and rpminspect-data-fedora.

License and source inspection tools

These tools are used for evaluating the state of licensing in the software being packaged for Fedora Linux. All of these tools are distribution-agnostic.


Licensecheck is a tool used to evaluate source files for their licensing. This tool is principally used in the Fedora context for the initial package review for packages to be included in the Fedora Linux distribution. It is run automaically as part of FedoraReview.

Licensecheck, by default, provides license reports with the full license names, but can be told to produce output using any number of license identifier schemes.

This is packaged in Fedora Linux as licensecheck.


SPDX-license-diff is a Firefox and Chromium/Chrome plugin that compares highlighted text of a license as displayed on a web page to find the closest match to something on the SPDX License List. If a match to an SPDX identifier is given as close to but less than 100%, SPDX-license-diff will show you differences in the texts.

Good for: Quick identification as compared to SPDX License List for a specific license text.

Tips for using: In some cases, differences will display that are actually accounted for by the SPDX matching guidelines. If it’s a close match, (e.g., only the name of the copyright holder or author, or other non-substantive seeming differences) it is recommended to cross-check against the actual template that the SPDX license list uses to implement (some of) the matching guidelines.

SPDX Check License

SPDX Check License (source code)- is a Django application in which you paste the text of a license or exception into a text box and it will match it against all the licenses and exceptions in the SPDX License List, implementing the SPDX Matching Guidelines. Because of its thoroughness, this tool may take more time to give an answer than SPDX-license-diff. It will tell you if there is a match or not and if it finds a close match, but won’t indicate a diff.


How to find or use: GitHub repository

Good for: Useful for quick analysis of packages coming out of ecosystems featuring projects known to have (1) highly standardized approaches to layout of license information (e.g., (it specifically looks only for files that are named LICENSE or COPYING or some obvious variant on those), (2) generally simple license makeup, and (3) cultural preferences for a highly limited set of licenses (for example, Rust crates that don’t bundle legacy C code, Golang modules, Node.js npm packages).

Shortcomings: It can’t recognize or understand: (1) license notices/license texts that are comments in source files, (2) license notices/license texts in README files, (3) license files that contain multiple license texts (or it will only recognize the first of them), (4) nonstandard/archaic/legacy licenses (which covers most of the licenses being reviewed in issues in fedora-license-data)

This is packaged in Fedora Linux as askalono-cli.


FOSSology is a license compliance software system and tooklit that includes license scanning. The information here focuses on that aspect of the toolkit. It can be run locally and also can be set up as a hosted services. See Get Started for ways to install and a link to a test instance that anyone can use.

Good for: Scanning an entire package for licenses or text that looks like licenses. Ability to view files easily in interface and remember license inspection decisions.

Tips on using: * In options: #5 - check "Ignore SCM files"; #7 - check Monk, Nomos, Ojo License Analysis and Package Analysis; #8 - check first two options re: "Scanners matches…​" * Go to License Browswer view. Look for license matches that are suspicious or unexpected, such as things that are not an SPDX id or ambiguous. You can then view the files with those matches and inspect what was found to determine if there is a license that needs to be recorded or if it is a false match. Basic Workflow has some helpful information.

Packaged in Fedora Linux: No

ScanCode toolkit

ScanCode is a comprehensive tool, written in Python, for detecting licenses and related information in source code. ScanCode output reports detected license information using both ScanCode’s own non-SPDX system of license keys and corresponding SPDX expressions; however it is not clear that ScanCode uses the SPDX matching guidelines in making such determinations.

ScanCode toolkit is a command line program and can be installed using pip. The output formats vary (text, JSON, HTML, and others) and some packagers may find it useful to gather licensing information from ScanCode toolkit using their own script. As mentioned above, ScanCode does not strictly produce SPDX compliant expressions so if you use this tool be sure it is to cross reference what another tool or your own scanning found.