seL4

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These are the Passing level criteria. You can also view the Silver or Gold level criteria.

        

 Basics 13/13

  • Identification

    The seL4 microkernel

    What programming language(s) are used to implement the project?
  • Basic project website content


    The project website MUST succinctly describe what the software does (what problem does it solve?). [description_good]

    The project website MUST provide information on how to: obtain, provide feedback (as bug reports or enhancements), and contribute to the software. [interact]

    To obtain: see top line of https://docs.sel4.systems To contribute: see https://sel4.systems/Contribute.html For contact: https://sel4.systems/contact.html



    The information on how to contribute MUST explain the contribution process (e.g., are pull requests used?) (URL required) [contribution]

    The main contribution guidelines are in https://docs.sel4.systems/processes/contributing.html, additional guidelines specific to seL4 in https://docs.sel4.systems/projects/sel4/kernel-contribution.html. Both are reachable from the CONTRIBUTION.md file in the repository and the main "Contribute" link on the home page at https://sel4.systems/Contribute.html



    The information on how to contribute SHOULD include the requirements for acceptable contributions (e.g., a reference to any required coding standard). (URL required) [contribution_requirements]

    See "Conventions" at the top of https://docs.sel4.systems/processes/contributing.html. The "Pull requests" link from that page also contains required tests, and formal verification.


  • FLOSS license

    What license(s) is the project released under?



    The software produced by the project MUST be released as FLOSS. [floss_license]

    Kernel code in the seL4 repository is licensed under GPL-2.0-only. Library code on top of the kernel under BSD-2-Clause. See also https://github.com/seL4/seL4/blob/master/LICENSE.md The GPL-2.0-only license is approved by the Open Source Initiative (OSI).



    It is SUGGESTED that any required license(s) for the software produced by the project be approved by the Open Source Initiative (OSI). [floss_license_osi]

    Both GPL-2.0-only and BSD-2-Clause are OSI approved. See also https://github.com/seL4/seL4/tree/master/LICENSES for the full list of things that are mentioned by any auxiliary tools and files. The GPL-2.0-only license is approved by the Open Source Initiative (OSI).



    The project MUST post the license(s) of its results in a standard location in their source repository. (URL required) [license_location]
  • Documentation


    The project MUST provide basic documentation for the software produced by the project. [documentation_basics]

    The sources of the reference manual are kept in https://github.com/seL4/seL4/tree/master/manual. There is an entire separate documentation site for seL4 at https://docs.sel4.systems



    The project MUST provide reference documentation that describes the external interface (both input and output) of the software produced by the project. [documentation_interface]

    The reference manual includes a full API description. See chapter 10 of https://sel4.systems/Info/Docs/seL4-manual-latest.pdf


  • Other


    The project sites (website, repository, and download URLs) MUST support HTTPS using TLS. [sites_https]

    Given only https: URLs.



    The project MUST have one or more mechanisms for discussion (including proposed changes and issues) that are searchable, allow messages and topics to be addressed by URL, enable new people to participate in some of the discussions, and do not require client-side installation of proprietary software. [discussion]

    GitHub supports discussions on issues and pull requests.



    The project SHOULD provide documentation in English and be able to accept bug reports and comments about code in English. [english]

    The main project language is English



    The project MUST be maintained. [maintained]

    The project is maintained by the seL4 Foundation https://sel4.systems/Foundation.html



(Advanced) What other users have additional rights to edit this badge entry? Currently: []



  • Public version-controlled source repository


    The project MUST have a version-controlled source repository that is publicly readable and has a URL. [repo_public]

    Repository on GitHub, which provides public git repositories with URLs.



    The project's source repository MUST track what changes were made, who made the changes, and when the changes were made. [repo_track]

    Repository on GitHub, which uses git. git can track the changes, who made them, and when they were made.



    To enable collaborative review, the project's source repository MUST include interim versions for review between releases; it MUST NOT include only final releases. [repo_interim]

    The project repository includes the entire development history between releases.



    It is SUGGESTED that common distributed version control software be used (e.g., git) for the project's source repository. [repo_distributed]

    Repository on GitHub, which uses git. git is distributed.


  • Unique version numbering


    The project results MUST have a unique version identifier for each release intended to be used by users. [version_unique]

    seL4 uses semantic versioning



    It is SUGGESTED that the Semantic Versioning (SemVer) or Calendar Versioning (CalVer) version numbering format be used for releases. It is SUGGESTED that those who use CalVer include a micro level value. [version_semver]


    It is SUGGESTED that projects identify each release within their version control system. For example, it is SUGGESTED that those using git identify each release using git tags. [version_tags]

    seL4 uses git tags and the GitHub release mechanism to identify releases


  • Release notes


    The project MUST provide, in each release, release notes that are a human-readable summary of major changes in that release to help users determine if they should upgrade and what the upgrade impact will be. The release notes MUST NOT be the raw output of a version control log (e.g., the "git log" command results are not release notes). Projects whose results are not intended for reuse in multiple locations (such as the software for a single website or service) AND employ continuous delivery MAY select "N/A". (URL required) [release_notes]

    Release notes are posted on the seL4 website, see e.g. https://docs.sel4.systems/releases/sel4/12.1.0



    The release notes MUST identify every publicly known run-time vulnerability fixed in this release that already had a CVE assignment or similar when the release was created. This criterion may be marked as not applicable (N/A) if users typically cannot practically update the software themselves (e.g., as is often true for kernel updates). This criterion applies only to the project results, not to its dependencies. If there are no release notes or there have been no publicly known vulnerabilities, choose N/A. [release_notes_vulns]

    seL4 has not any CVE assignments or similar yet, but any security improvements are identified in the release notes.


  • Bug-reporting process


    The project MUST provide a process for users to submit bug reports (e.g., using an issue tracker or a mailing list). (URL required) [report_process]

    The project SHOULD use an issue tracker for tracking individual issues. [report_tracker]

    The project MUST acknowledge a majority of bug reports submitted in the last 2-12 months (inclusive); the response need not include a fix. [report_responses]

    Almost all issues on https://github.com/seL4/seL4/issues have a response (apart from those that we use for internal tracking).



    The project SHOULD respond to a majority (>50%) of enhancement requests in the last 2-12 months (inclusive). [enhancement_responses]

    Almost all issues on https://github.com/seL4/seL4/issues have a response. Most issues are enhancement requests or questions.



    The project MUST have a publicly available archive for reports and responses for later searching. (URL required) [report_archive]

    See https://github.com/seL4/seL4/issues for current and https://sel4.atlassian.net/ for older issues (latter requires account, but account creation is possible for anyone).


  • Vulnerability report process


    The project MUST publish the process for reporting vulnerabilities on the project site. (URL required) [vulnerability_report_process]

    If private vulnerability reports are supported, the project MUST include how to send the information in a way that is kept private. (URL required) [vulnerability_report_private]

    The project provides a gpg key for private communication, see "Official channel" in https://github.com/seL4/seL4/blob/master/SECURITY.md



    The project's initial response time for any vulnerability report received in the last 6 months MUST be less than or equal to 14 days. [vulnerability_report_response]

    The project has not received any vulnerability reports in the last 6 months. Vulnerabilities in seL4 are extremely rare.


  • Working build system


    If the software produced by the project requires building for use, the project MUST provide a working build system that can automatically rebuild the software from source code. [build]

    The project uses CMake



    It is SUGGESTED that common tools be used for building the software. [build_common_tools]

    CMake is commonly used.



    The project SHOULD be buildable using only FLOSS tools. [build_floss_tools]

    All build tools needed for seL4 are FLOSS tools.


  • Automated test suite


    The project MUST use at least one automated test suite that is publicly released as FLOSS (this test suite may be maintained as a separate FLOSS project). The project MUST clearly show or document how to run the test suite(s) (e.g., via a continuous integration (CI) script or via documentation in files such as BUILD.md, README.md, or CONTRIBUTING.md). [test]

    A test suite SHOULD be invocable in a standard way for that language. [test_invocation]

    The test suite uses a standard init, compile, run cycle. See e.g. https://docs.sel4.systems/GettingStarted.html#running-sel4



    It is SUGGESTED that the test suite cover most (or ideally all) the code branches, input fields, and functionality. [test_most]

    The sel4test suite covers most (but not all) of the branches of seL4.



    It is SUGGESTED that the project implement continuous integration (where new or changed code is frequently integrated into a central code repository and automated tests are run on the result). [test_continuous_integration]

    The project currently is running CI for both tests and formal verification. See e.g. https://sel4.systems/~bamboo/logs/RELEASE-SEL4TEST-HWTESTSGHSTATUS/1124/ for an example.


  • New functionality testing


    The project MUST have a general policy (formal or not) that as major new functionality is added to the software produced by the project, tests of that functionality should be added to an automated test suite. [test_policy]

    The policy for new feature testing is informal (but implied). The policy for requiring formal verification is explicit. See e.g. section on Tests in https://docs.sel4.systems/processes/code-review.html



    The project MUST have evidence that the test_policy for adding tests has been adhered to in the most recent major changes to the software produced by the project. [tests_are_added]

    The last releases have not included major API changes (mostly refactoring, performance improvements, build system improvements, and fixes in experimental features), but you can see reviewers requiring tests on pull requests, e.g. https://github.com/seL4/seL4/pull/322#pullrequestreview-686920158 or https://github.com/seL4/seL4/pull/322#issuecomment-865432029 on a pull request for an experimental feature that would be switched off by default (not yet released).



    It is SUGGESTED that this policy on adding tests (see test_policy) be documented in the instructions for change proposals. [tests_documented_added]
  • Warning flags


    The project MUST enable one or more compiler warning flags, a "safe" language mode, or use a separate "linter" tool to look for code quality errors or common simple mistakes, if there is at least one FLOSS tool that can implement this criterion in the selected language. [warnings]

    The project MUST address warnings. [warnings_fixed]

    All compiler warnings are addressed (running on -Werror)



    It is SUGGESTED that projects be maximally strict with warnings in the software produced by the project, where practical. [warnings_strict]
  • Secure development knowledge


    The project MUST have at least one primary developer who knows how to design secure software. (See ‘details’ for the exact requirements.) [know_secure_design]

    The members of the technical steering committee of the seL4 Foundation all satisfy this requirement (see https://sel4.systems/Foundation/TSC/index.html). Multiple of these teach secure operating systems at Universities, and/or have senior positions in companies that build secure software.



    At least one of the project's primary developers MUST know of common kinds of errors that lead to vulnerabilities in this kind of software, as well as at least one method to counter or mitigate each of them. [know_common_errors]

    All members of the seL4 verification team, who produced mathematical code-level proofs (many of which are also developers) satisfy this requirement. All of the members of the technical steering committee of the seL4 Foundation also satisfy this requirement (see https://sel4.systems/Foundation/TSC/index.html).


  • Use basic good cryptographic practices

    Note that some software does not need to use cryptographic mechanisms. If your project produces software that (1) includes, activates, or enables encryption functionality, and (2) might be released from the United States (US) to outside the US or to a non-US-citizen, you may be legally required to take a few extra steps. Typically this just involves sending an email. For more information, see the encryption section of Understanding Open Source Technology & US Export Controls.

    The software produced by the project MUST use, by default, only cryptographic protocols and algorithms that are publicly published and reviewed by experts (if cryptographic protocols and algorithms are used). [crypto_published]

    seL4 does not use cryptographic mechanisms



    If the software produced by the project is an application or library, and its primary purpose is not to implement cryptography, then it SHOULD only call on software specifically designed to implement cryptographic functions; it SHOULD NOT re-implement its own. [crypto_call]

    seL4 does not use cryptographic mechanisms



    All functionality in the software produced by the project that depends on cryptography MUST be implementable using FLOSS. [crypto_floss]

    seL4 does not use cryptographic mechanisms



    The security mechanisms within the software produced by the project MUST use default keylengths that at least meet the NIST minimum requirements through the year 2030 (as stated in 2012). It MUST be possible to configure the software so that smaller keylengths are completely disabled. [crypto_keylength]

    seL4 does not use cryptographic mechanisms



    The default security mechanisms within the software produced by the project MUST NOT depend on broken cryptographic algorithms (e.g., MD4, MD5, single DES, RC4, Dual_EC_DRBG), or use cipher modes that are inappropriate to the context, unless they are necessary to implement an interoperable protocol (where the protocol implemented is the most recent version of that standard broadly supported by the network ecosystem, that ecosystem requires the use of such an algorithm or mode, and that ecosystem does not offer any more secure alternative). The documentation MUST describe any relevant security risks and any known mitigations if these broken algorithms or modes are necessary for an interoperable protocol. [crypto_working]

    seL4 does not use cryptographic mechanisms



    The default security mechanisms within the software produced by the project SHOULD NOT depend on cryptographic algorithms or modes with known serious weaknesses (e.g., the SHA-1 cryptographic hash algorithm or the CBC mode in SSH). [crypto_weaknesses]

    seL4 does not use cryptographic mechanisms



    The security mechanisms within the software produced by the project SHOULD implement perfect forward secrecy for key agreement protocols so a session key derived from a set of long-term keys cannot be compromised if one of the long-term keys is compromised in the future. [crypto_pfs]

    seL4 does not use cryptographic mechanisms



    If the software produced by the project causes the storing of passwords for authentication of external users, the passwords MUST be stored as iterated hashes with a per-user salt by using a key stretching (iterated) algorithm (e.g., Argon2id, Bcrypt, Scrypt, or PBKDF2). See also OWASP Password Storage Cheat Sheet. [crypto_password_storage]

    seL4 does not use cryptographic mechanisms



    The security mechanisms within the software produced by the project MUST generate all cryptographic keys and nonces using a cryptographically secure random number generator, and MUST NOT do so using generators that are cryptographically insecure. [crypto_random]

    seL4 does not use cryptographic mechanisms


  • Secured delivery against man-in-the-middle (MITM) attacks


    The project MUST use a delivery mechanism that counters MITM attacks. Using https or ssh+scp is acceptable. [delivery_mitm]

    Assuming this is for software releases, the project uses https. Otherwise, N/A.



    A cryptographic hash (e.g., a sha1sum) MUST NOT be retrieved over http and used without checking for a cryptographic signature. [delivery_unsigned]

    Assuming this is for software releases, the project uses, the project uses GitHub's release mechanism and git hashes (the kernel is usually built from source for use).


  • Publicly known vulnerabilities fixed


    There MUST be no unpatched vulnerabilities of medium or higher severity that have been publicly known for more than 60 days. [vulnerabilities_fixed_60_days]

    No such vulnerabilities are known.



    Projects SHOULD fix all critical vulnerabilities rapidly after they are reported. [vulnerabilities_critical_fixed]

    No such vulnerabilities are known.


  • Other security issues


    The public repositories MUST NOT leak a valid private credential (e.g., a working password or private key) that is intended to limit public access. [no_leaked_credentials]

    The project contains no private credentials.


  • Static code analysis


    At least one static code analysis tool (beyond compiler warnings and "safe" language modes) MUST be applied to any proposed major production release of the software before its release, if there is at least one FLOSS tool that implements this criterion in the selected language. [static_analysis]

    The project does use static analysis such as Coverity, but its main static analysis is full machine-checked mathematical, code-level verification of C code base. This is the strongest form of static analysis possible, and subsumes dynamic analysis tools as well for this application. The proof scripts for seL4 are available at https://github.com/seL4/l4v together with instructions on how to check them separately. These proofs are run as part of CI.



    It is SUGGESTED that at least one of the static analysis tools used for the static_analysis criterion include rules or approaches to look for common vulnerabilities in the analyzed language or environment. [static_analysis_common_vulnerabilities]

    The formal seL4 proofs cover all known common vulnerabilities such as buffer overflows, null pointer dereferences, etc. They do not (yet) cover timing side channels, but neither does any other common static analysis we are aware of.



    All medium and higher severity exploitable vulnerabilities discovered with static code analysis MUST be fixed in a timely way after they are confirmed. [static_analysis_fixed]

    The formal proofs are part of CI and must pass before any code change is accepted into the kernel repository. The exception from this are experimental features that are marked as such, and unverified architecture ports, which are also marked as such.



    It is SUGGESTED that static source code analysis occur on every commit or at least daily. [static_analysis_often]

    The proofs run on every commit.


  • Dynamic code analysis


    It is SUGGESTED that at least one dynamic analysis tool be applied to any proposed major production release of the software before its release. [dynamic_analysis]

    The formal proofs subsume any errors that dynamic analysis tools can detect. In addition, the afl fuzzer has been run on kernel code that is not formally verified, e.g. experimental features and platform ports that are marked as unverified, but not for every release. Dynamic analysis in the form of runtime assertions for a full test suite (sel4test) is done for every commit (and release), including code that is not formally verified.



    It is SUGGESTED that if the software produced by the project includes software written using a memory-unsafe language (e.g., C or C++), then at least one dynamic tool (e.g., a fuzzer or web application scanner) be routinely used in combination with a mechanism to detect memory safety problems such as buffer overwrites. If the project does not produce software written in a memory-unsafe language, choose "not applicable" (N/A). [dynamic_analysis_unsafe]

    The formal seL4 proofs guarantee the absence of any memory safety errors in C. Tests with assertions guard against potential memory safety issues such as object overlap in code that is experimental and/or not formally verified.



    It is SUGGESTED that the project use a configuration for at least some dynamic analysis (such as testing or fuzzing) which enables many assertions. In many cases these assertions should not be enabled in production builds. [dynamic_analysis_enable_assertions]

    Assertions are on for debug builds only and are used in development for new features or refactoring.



    All medium and higher severity exploitable vulnerabilities discovered with dynamic code analysis MUST be fixed in a timely way after they are confirmed. [dynamic_analysis_fixed]

    All issues detected during the formal proofs are fixed before pull requests are accepted. Any issues (security, correctness, or otherwise) on code that is experimental and/or not formally verified are fixed either before pull request are accepted, or if only discovered later, fixed as soon as possible. seL4 releases typically do not contain any known security issues.



This data is available under the Creative Commons Attribution version 3.0 or later license (CC-BY-3.0+). All are free to share and adapt the data, but must give appropriate credit. Please credit Gerwin Klein and the OpenSSF Best Practices badge contributors.

Project badge entry owned by: Gerwin Klein.
Entry created on 2021-06-30 05:53:00 UTC, last updated on 2021-07-01 02:50:15 UTC. Last achieved passing badge on 2021-06-30 07:33:16 UTC.

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