Better diff'ing experience by MSirringhaus

Description

For diff-ing directories, I usually like to use meld, but it struggles a lot with large trees. Experiment with writing a TUI meld-clone for diffing directories and files

Goals

Get first prototype going of a TUI that can show

• diffs of text-files
• diffs of directories.

Stretch goals

• Themes
• Filters (no whitespace, etc.)
• Live config changes (Show/hide line numbers, etc.)

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Agama installer on-line demo by lslezak

Description

The Agama installer provides a quite complex user interface. We have some screenshots on the web page but as it is basically a web application it would be nice to have some on-line demo where users could click and check it live.

The problem is that the Agama server directly accesses the hardware (storage probing) and loads installation repositories. We cannot easily mock this in the on-line demo so the easiest way is to have just a read-only demo. You could explore the configuration options but you could not change anything, all changes would be ignored.

The read-only demo would be a bit limited but I still think it would be useful for potential users get the feeling of the new Agama installer and get familiar with it before using in a real installation.

As a proof of concept I already created this on-line demo.

The implementation basically builds Agama in two modes - recording mode where it saves all REST API responses and replay mode where it for the REST API requests returns the previously recorded responses. Recording in the browser is inconvenient and error prone, there should be some scripting instead (see below).

Goals

• Create an Agama on-line demo which can be easily tested by users
• The Agama installer is still in alpha phase and in active development, the online demo needs to be easily rebuilt with the latest Agama version
• Ideally there should be some automation so the demo page is rebuilt automatically without any developer interactions (once a day or week?)

TODO

• Use OpenAPI to get all Agama REST API endpoints, write a script which queries all the endpoints automatically and saves the collected data to a file (see this related PR).
• Write a script for starting an Agama VM (use libvirt/qemu?), the script should ensure we always use the same virtual HW so if we need to dump the latest REST API state we get the same (or very similar data). This should ensure the demo page does not change much regarding the storage proposal etc...
• Fix changing the product, currently it gets stuck after clicking the "Select" button.
• Move the mocking data (the recorded REST API responses) outside the Agama sources, it's too big and will be probably often updated. To avoid messing the history keep it in a separate GitHub repository
• Allow changing the UI language
• Display some note (watermark) in the page so it is clear it is a read-only demo (probably with some version or build date to know how old it is)
• Automation for building new demo page from the latest sources. There should be some check which ensures the recorded data still matches the OpenAPI specification.

Changing the UI language

This will be quite tricky because selecting the proper translation file is done on the server side. We would probably need to completely re-implement the logic in the browser side and adapt the server for that.

Also some REST API responses contain translated texts (storage proposal, pattern names in software). We would need to query the respective endpoints in all supported languages and return the correct response in runtime according to the currently selected language.

Resources

• Agama sources
• Experimental proof of concept demo
• The respective source code change

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Hacking on sched_ext by flonnegren

Description

Sched_ext upstream has some interesting issues open for grabs:

• core event counters
• topology: Use cpumasks

Goals

Send patches to sched_ext upstream

Also set up perfetto to trace some of the example schedulers.

Resources

https://github.com/sched-ext/scx

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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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Hack on isotest-ng - a rust port of isotovideo (os-autoinst aka testrunner of openQA) by szarate

Description

Some time ago, I managed to convince ByteOtter to hack something that resembles isotovideo but in Rust, not because I believe that Perl is dead, but more because there are certain limitations in the perl code (how it was written), and its always hard to add new functionalities when they are about implementing a new backend, or fixing bugs (Along with people complaining that Perl is dead, and that they don't like it)

In reality, I wanted to see if this could be done, and ByteOtter proved that it could be, while doing an amazing job at hacking a vnc console, and helping me understand better what RuPerl needs to work.

I plan to keep working on this for the next few years, and while I don't aim for feature completion or replacing isotovideo tih isotest-ng (name in progress), I do plan to be able to use it on a daily basis, using specialized tooling with interfaces, instead of reimplementing everything in the backend

Todo

• Add make targets for testability, e.g "spawn qemu and type"
• Add image search matching algorithm
• Add a Null test distribution provider
• Add a Perl Test Distribution Provider
• Fix unittests https://github.com/os-autoinst/isotest-ng/issues/5
• Research OpenTofu how to add new hypervisors/baremetal to OpenTofu
• Add an interface to openQA cli

Goals

• Implement at least one of the above, prepare proposals for GSoC
• Boot a system via it's BMC

Resources

See https://github.com/os-autoinst/isotest-ng

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early stage kdump support by mbrugger

Project Description

When we experience a early boot crash, we are not able to analyze the kernel dump, as user-space wasn't able to load the crash system. The idea is to make the crash system compiled into the host kernel (think of initramfs) so that we can create a kernel dump really early in the boot process.

Goal for the Hackweeks

1. Investigate if this is possible and the implications it would have (done in HW21)
2. Hack up a PoC (done in HW22 and HW23)
3. Prepare RFC series (giving it's only one week, we are entering wishful thinking territory here).

update HW23

• I was able to include the crash kernel into the kernel Image.
• I'll need to find a way to load that from init/main.c:start_kernel() probably after kcsan_init()
• I workaround for a smoke test was to hack kexec_file_load() systemcall which has two problems:
  1. My initramfs in the porduction kernel does not have a new enough kexec version, that's not a blocker but where the week ended
  2. As the crash kernel is part of init.data it will be already stale once I can call kexec_file_load() from user-space.

The solution is probably to rewrite the POC so that the invocation can be done from init.text (that's my theory) but I'm not sure if I can reuse the kexec infrastructure in the kernel from there, which I rely on heavily.

update HW24

• Day1
  • rebased on v6.12 with no problems others then me breaking the config
  • setting up a new compilation and qemu/virtme env
  • getting desperate as nothing works that used to work
• Day 2
  • getting to call the invocation of loading the early kernel from __init after kcsan_init()

• Day 3

  • fix problem of memdup not being able to alloc so much memory... use 64K page sizes for now
  • code refactoring
  • I'm now able to load the crash kernel
  • When using virtme I can boot into the crash kernel, also it doesn't boot completely (major milestone!), crash in elfcorehdr_read_notes()

• Day 4

  • crash systems crashes (no pun intended) in copy_old_mempage() link; will need to understand elfcorehdr...
  • call path vmcore_init() -> parse_crash_elf_headers() -> elfcorehdr_read() -> read_from_oldmem() -> copy_oldmem_page() -> copy_to_iter()

• Day 5

  • hacking arch/arm64/kernel/crash_dump.c:copy_old_mempage() to see if crash system really starts. It does.
  • fun fact: retested with more reserved memory and with UEFI FW, host kernel crashes in init but directly starts the crash kernel, so it works (somehow) \o/

• TODOs

  • fix elfcorehdr so that we actually can make use of all this...
  • test where in the boot __init() chain we can/should call kexec_early_dump()

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Improve UML page fault handler by ptesarik

Description

Improve UML handling of segmentation faults in kernel mode. Although such page faults are generally caused by a kernel bug, it is annoying if they cause an infinite loop, or panic the kernel. More importantly, a robust implementation allows to write KUnit tests for various guard pages, preventing potential kernel self-protection regressions.

Goals

Convert the UML page fault handler to use oops_* helpers, go through a few review rounds and finally get my patch series merged in 6.14.

Resources

Wrong initial attempt: https://lore.kernel.org/lkml/20231215121431.680-1-petrtesarik@huaweicloud.com/T/

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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

The story so far

• Day 1: setting up a virtual machine for kernel development using Tumbleweed. Reading a lot of documentation, taking confidence with Coverity dashboard and with procedures to submit a kernel patch
• Day 2: I read really a lot of documentation and I triaged some findings on Coverity SAST dashboard. I have to confirm that SAST tool are great false positives generator, even for low hanging fruits.
• Day 3: Working on trivial changes after I read this blog post: https://www.toblux.com/posts/2024/02/linux-kernel-patches.html. I have to take confidence with the patch preparation and submit process yet.
  • First trivial patch sent: using strtruefalse() macro instead of hard-coded strings in a staging driver for a lcd display
  • Fix for a dereference before null check issue discovered by Coverity (CID 1601566) https://scan7.scan.coverity.com/#/project-view/52110/11354?selectedIssue=1601566
• Day 4: Triaging more issues found by Coverity.
  • The patch for CID 1601566 was refused. The check against the NULL pointer was pointless so I prepared a version 2 of the patch removing the check.
  • Fixed another dereference before NULL check in iwlmvmparsewowlaninfo_notif() routine (CID 1601547). This one was already submitted by another kernel hacker :(
• Day 5: Wrapping up. I had to do some minor rework on patch for CID 1601566. I found a stalker bothering me in private emails and people I interacted with me, advised he is a well known bothering person. Markus Elfring for the record.

• Wrapping up: being back doing kernel hacking is amazing and I don't want to stop it. My battery pack is completely drained but changing the scope gave me a great twist and I really want to feel this energy not doing a single task for months.

  I failed in setting up a fuzzing lab but I was too optimistic for the patch submission process.

The patches

1

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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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RISC-V emulator in GLSL capable of running Linux by favogt

Description

There are already numerous ways to run Linux and some programs through emulation in a web browser (e.g. x86 and riscv64 on https://bellard.org/jslinux/), but none use WebGL/WebGPU to run the emulation on the GPU.

I already made a PoC of an AArch64 (64-bit Arm) emulator in OpenCL which is unfortunately hindered by a multitude of OpenCL compiler bugs on all platforms (Intel with beignet or the new compute runtime and AMD with Mesa Clover and rusticl). With more widespread and thus less broken GLSL vs. OpenCL and the less complex implementation requirements for RV32 (especially 32bit integers instead of 64bit), that should not be a major problem anymore.

Goals

Write an RISC-V system emulator in GLSL that is capable of booting Linux and run some userspace programs interactively. Ideally it is small enough to work on online test platforms like Shaderoo with a custom texture that contains bootstrap code, kernel and initrd.

Minimum:

riscv32 without FPU (RV32 IMA) and MMU (µClinux), running Linux in M-mode and userspace in U-mode.

Stretch goals:

FPU support, S-Mode support with MMU, SMP. Custom web frontend with more possibilities for I/O (disk image, network?).

Resources

RISC-V ISA Specifications
Shaderoo
OpenGL 4.5 Quick Reference Card

Result as of Hackweek 2024

WebGL turned out to be insufficient, it only supports OpenGL ES 3.0 but imageLoad/imageStore needs ES 3.1. So we switched directions and had to write a native C++ host for the shaders.

As of Hackweek Friday, the kernel attempts to boot and outputs messages, but panics due to missing memory regions.

Since then, some bugs were fixed and enough hardware emulation implemented, so that now Linux boots with framebuffer support and it's possible to log in and run programs!

The repo with a demo video is available at https://github.com/Vogtinator/risky-v

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