Modularization and Modernization of cifs.ko for Enhanced SMB Protocol Support by hcarvalho

Creator:
Enzo Matsumiya ematsumiya@suse.de @ SUSE Samba team
Members:
Henrique Carvalho henrique.carvalho@suse.com @ SUSE Samba team

Description

Split cifs.ko in 2 separate modules; one for SMB 1.0 and 2.0.x, and another for SMB 2.1, 3.0, and 3.1.1.

Goals

Primary

Start phasing out/deprecation of older SMB versions

Secondary

• Clean up of the code (with focus on the newer versions)
• Update cifs-utils
• Update documentation
• Improve backport workflow (see below)

Technical details

Ideas for the implementation.

• fs/smb/client/{old,new}.c to generate the respective modules
  • Maybe don't create separate folders? (re-evaluate as things progresses!)
• Remove server->{ops,vals} if possible
• Clean up fs_context.* -- merge duplicate options into one, handle them in userspace utils
• Reduce code in smb2pdu.c -- tons of functions with very similar init/setup -> send/recv -> handle/free flow
• Restructure multichannel
  • Treat initial connection as "channel 0" regardless of multichannel enabled/negotiated status, proceed with extra channels accordingly
  • Extra channel just point to "channel 0" as the primary server, no need to allocate an extra TCPServerInfo for each one
• Authentication mechanisms
  • Modernize algorithms (references: himmelblau, IAKERB/Local KDC, SCRAM, oauth2 (Azure), etc.

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Create DRM drivers for VESA and EFI framebuffers by tdz

Description

We already have simpledrm for firmware framebuffers. But the driver is originally for ARM boards, not PCs. It is already overloaded with code to support both use cases. At the same time it is missing possible features for VESA and EFI, such as palette modes or EDID support. We should have DRM drivers for VESA and EFI interfaces. The infrastructure exists already and initial drivers can be forked from simpledrm.

Goals

• Initially, a bare driver for VESA or EFI should be created. It can take functionality from simpledrm.
• Then we can begin to add additional features. The boot loader can provide EDID data. With VGA hardware, VESA can support paletted modes or color management. Example code exists in vesafb.

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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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Modernize ocfs2 by goldwynr

Ocfs2 has gone into a stage of neglect and disrepair. Modernize the code to generate enough interest.

Goals: * Change the mount sequence to use fscontext * Move from using bufferhead to bio/folios * Use iomap * Run it through xfstests

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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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Investigate non-booting Forlinx OKMX8MX-C board (aarch64) by a_faerber

Description

In the context of a SUSE customer inquiry last year, a Forlinx OKMX8MX-C arm64 board had been relayed to me from China that a customer was not successful booting SUSE Linux Micro on. Typically this happens when the vendor's bootloader (e.g., U-Boot) is not configured properly (e.g., U-Boot's distro boot) to be compliant with Arm SystemReady Devicetree (formerly IR) band. Unfortunately I could not immediately get it to emit any output, to even diagnose why it wasn't working. There was no public documentation on the vendor's website to even confirm I was checking the right UARTs.

Earlier this year (2024) I happened to meet the ODM/OEM, Forlinx, at Embedded World 2024 in Nuremberg and again the Monday before Hackweek 24 at Electronica 2024 in Munich. The big puzzle was that the PCB print "OKMX8MX-C" does not match any current Forlinx product, there being OKMX8MM-C and OKMX8MP-C products with the Mini and Plus variants of NXP i.MX 8M family instead. One suggestion from Forlinx staff was to double-check the DIP switches on the board for boot mode selection.

Goals

Double-check the board name and investigate further what may be wrong with this board.

Resources

none

Progress

• The board name is indeed as spelled above, not matching any product on forlinx.net.
• The DIP switches were set to boot from microSD.
• Changing the DIP switches to eMMC boot did result in UART1 RS-232 output! (although at times garbled with the cable supplied and USB adapter used)
• As feared, it did not automatically load our GRUB from USB.
• Booting our GRUB manually from USB (via eMMC U-Boot commands fatload+bootefi) was unsuccessful, with partially Chinese error messages.
• This confirmed the initial suspicion, already shared with Forlinx at Embedded World 2024, that the Forlinx System-on-Module's boot firmware was not Arm SystemReady Devicetree compliant and that a firmware update would be necessary to remedy that.
• The microSD card turned out not to contain a bootable image but to only include Chinese-language board documentation (dated 20220507) and BSP files. They used a diverging name of OKMX8MQ-C.

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