Model checking the BPF verifier by shunghsiyu

Project Description

BPF verifier plays a crucial role in securing the system (though less so now that unprivileged BPF is disabled by default in both upstream and SLES), and bugs in the verifier has lead to privilege escalation vulnerabilities in the past (e.g. CVE-2021-3490).

One way to check whether the verifer has bugs to use model checking (a formal verification technique), in other words, build a abstract model of how the verifier operates, and then see if certain condition can occur (e.g. incorrect calculation during value tracking of registers) by giving both the model and condition to a solver.

For the solver I will be using the Z3 SMT solver to do the checking since it provide a Python binding that's relatively easy to use.

Goal for this Hackweek

Learn how to use the Z3 Python binding (i.e. Z3Py) to build a model of (part of) the BPF verifier, probably the part that's related to value tracking using tristate numbers (aka tnum), and then check that the algorithm work as intended.

Resources

• Formal Methods for the Informal Engineer: Tutorial #1 - The Z3 Theorem Prover and its accompanying notebook is a great introduction into Z3
  • Has a section specifically on model checking
• Software Verification and Analysis Using Z3 a great example of using Z3 for model checking
• Sound, Precise, and Fast Abstract Interpretation with Tristate Numbers - existing work that use formal verification to prove that the multiplication helper used for value tracking work as intended
• [PATCH v5 net-next 00/12] bpf: rewrite value tracking in verifier - initial patch set that adds tristate number to the verifier

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Kanidm: A safe and modern IDM system by firstyear

Kanidm is an IDM system written in Rust for modern systems authentication. The github repo has a detailed "getting started" on the readme.

Kanidm Github

In addition Kanidm has spawn a number of adjacent projects in the Rust ecosystem such as LDAP, Kerberos, Webauthn, and cryptography libraries.

In this hack week, we'll be working on Quokca, a certificate authority that supports PKCS11/TPM storage of keys, issuance of PIV certificates, and ACME without the feature gatekeeping implemented by other CA's like smallstep.

For anyone who wants to participate in Kanidm, we have documentation and developer guides which can help.

I'm happy to help and share more, so please get in touch!

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OIDC Loginproxy by toe

Description

Reverse proxies can be a useful option to separate authentication logic from application logic. SUSE and openSUSE use "loginproxies" as an authentication layer in front of several services.

Currently, loginproxies exist which support LDAP authentication or SAML authentication.

Goals

The goal of this Hack Week project is, to create another loginproxy which supports OpenID Connect authentication which can then act as a drop-in replacement for the existing LDAP or SAML loginproxies.

Testing is intended to focus on the integration with OIDC IDPs from Okta, KanIDM and Authentik.

Resources

• #122254: Migrate away from login proxies to SSO

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Contributing to Linux Kernel security by pperego

Description

A couple of weeks ago, I found this blog post by Gustavo Silva, a Linux Kernel contributor.

I always strived to start again into hacking the Linux Kernel, so I asked Coverity scan dashboard access and I want to contribute to Linux Kernel by fixing some minor issues.

I want also to create a Linux Kernel fuzzing lab using qemu and syzkaller

Goals

1. Fix at least 2 security bugs
2. Create the fuzzing lab and having it running

Resources

The dashboard

The serie of blog posts by Gustavo Silva inspiring this project.

An email with some quick "where to start" instructions The patchset philosophy

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CVE portal for SUSE Rancher products by gmacedo

Description

Currently it's a bit difficult for users to quickly see the list of CVEs affecting images in Rancher, RKE2, Harvester and Longhorn releases. Users need to individually look for each CVE in the SUSE CVE database page - https://www.suse.com/security/cve/ . This is not optimal, because those CVE pages are a bit hard to read and contain data for all SLE and BCI products too, making it difficult to easily see only the CVEs affecting the latest release of Rancher, for example. We understand that certain costumers are only looking for CVE data for Rancher and not SLE or BCI.

Goals

The objective is to create a simple to read and navigate page that contains only CVE data related to Rancher, RKE2, Harvester and Longhorn, where it's easy to search by a CVE ID, an image name or a release version. The page should also provide the raw data as an exportable CSV file.

It must be an MVP with the minimal amount of effort/time invested, but still providing great value to our users and saving the wasted time that the Rancher Security team needs to spend by manually sharing such data. It might not be long lived, as it can be replaced in 2-3 years with a better SUSE wide solution.

Resources

• The page must be simple and easy to read.
• The UI/UX must be as straightforward as possible with minimal visual noise.
• The content must be created automatically from the raw data that we already have internally.
• It must be updated automatically on a daily basis and on ad-hoc runs (when needed).
• The CVE status must be aligned with VEX.
• The raw data must be exportable as CSV file.
• Ideally it will be written in Go or pure Shell script with basic HTML and no external dependencies in CSS or JS.

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