users December 2017

users@lists.genode.org

16 participants
18 discussions

Individual file access
by Nobody III 16 Mar '18

16 Mar '18

To start off, I'm planning on building a component that handles file open/save requests for other components, primarily graphical applications. My plan is to use a qt5 QFileDialog for the user to select one or more files, then modify the vfs server's configuration to attach the selected file(s) to the component's filesystem. To attach individual files to a component's filesystem, it seems like I should write a server-side link vfs plugin. The plugin would be like a symlink, but would transparently resolve the link within the vfs server, providing access to otherwise inaccessible files. Is this possible? If so, can you give me some tips on how to implement it?

2 7

Memory write tracing/logging of an application / Watchpoints in Genode/Fiasco.OC
by Stark, Josef 14 Mar '18

14 Mar '18

Hi all, I want to be able to 'trace' every memory write access of an arbitrary target application, in order to 'duplicate' those writes into another memory location. So that I would then have at all times one exact copy of the memory area (stack and heap) used by that application. My plan was to realize this with the help of a parent application, that acts as a session-proxy for the target, i.e. target requests a RAM-session from parent, which forwards the request to core and then provides the session to target; thus, the parent later knows which dataspaces/ memory areas are used by target. It could then flag that whole memory area with watchpoints. Hence, parent would be notified about all write accesses made by target and could consequently duplicate those writes in a secondary memory location. (I know that this would probably incur a slowdown factor of 10-1000 times, but that is allowed in this scenario.) Sadly, only now I have read that watchpoints are not implemented in Genode, and most probably neither are they in the underlying kernel, Fiasco.OC, which I have to use; breakpoints on the other hand seem to work just fine. My question is: Could there possibly be another way to achieve my goal, or do I have to bite the bullet and implement watchpoints myself? Thanks for bearing with me and for any hints at all. Best, Josef

4 16

Roadmap 2018
by Norman Feske 21 Jan '18

21 Jan '18

Hello everyone, like every year in December, I'd like to kick off the discussion of Genode's road map for the upcoming twelve months. It goes without saying that your feedback and suggestions are very welcome. Should you have any plans related to Genode, please do not hesitate to chime in! Before I present my rough plans, let me take a minute to review the past year. Review of 2017 -------------- As Johannes Schlatow's team put it so nicely in their Christmas card (thanks a lot!), the "Turmvilla" era lies behind us. So let the "Sculpt" era begin! Whereas Turmvilla allowed me to work on a Genode-based system since mid of 2015, the scenario was quite rigid and required significant manual labour for any customization. Although it was not really inviting for potential users, it illustrated well that all the basic building blocks - in particular the driver stacks - were in place. But it would have been be quite a stretch to call Turmvilla a general-purpose OS at that point. The new Sculpt scenario that I started to put together this autumn leverages two key features of 2017 to ultimately enter the realms of general-purpose computing. Those features are the dynamic init and the package management. The combination of Genode's recursive architecture with the dynamic reconfigurability of the init component allows me to interactive shape the running Genode system including any subsystem or even configurations of individual components. The system structure is at my fingertips and I can change it instantly using my favorite text editor. This excites me to no end! :-) At the same time, the new package management greatly helps to keep the complexity at a manageable level. Whereas I rarely updated my Turmvilla installation out of hesitance to break my work environment, I routinely update Sculpt on a weekly basis. Not only do I but also all my team mates at Genode Labs! The switch of the entire Genode-Labs team to Genode full time was certainly our biggest milestone of the year. At the technical level, the use of the gained cross-kernel binary compatibility or the VFS infrastructure have already become a second nature. Regarding the latter, remodelling this infrastructure to an asynchronous mode of operation was certainly a long and stony way. I am extremely grateful to Emery and Christian for having taken a big share of this labor-intensive work! Now, we can start to reap the fruits of this development. How to proceed in 2018? ----------------------- Personally, I'm to eager to take Genode in two main directions. First, the Sculpt scenario will for sure spawn manifold developments to the benefit of end users. Those developments will include documentation to make Sculpt palatable to users, the further cultivation of Genode's package-management concept, the composition of new subsystems, and the optimization of daily work flows. The progress in this direction will be quite organic and primarily motivated to make our daily computing experience more effective and fun. The second direction is the application of Genode for real-time graphics and sound processing - in a way reigniting my past passion of programming demo effects on the Atari Falcon. ;-) The path for this activity was paved this year by Josef and Sebastian who created our driver infrastructure for Intel GPUs. By actively using this infrastructure along with the audio stack, I am eager to push Genode towards low-latency multimedia performance. In order to do that, I will have to improve the tools for gathering runtime data (e.g., putting our tracing infrastructure to good use), gain a profound understanding of the behavior of complex scenarios, and optimize. Aside these playful activities, I also want to focus on the quality and resilience of our software. The modernized framework API introduced last year is an important stepping stone. But there is much more we can (and should) do, I.e., learning from the high-integrity computing community (e.g., implementing critical components in SPARK), leveling-up the scope and intensity of our automated tests, facilitating static code analysis, and employing software-hardening techniques. Of course, this scope goes far beyond the time frame of one year. The immediate priorization of these topics will largely depend on the focus of commerical users funding the work. The aspirations outlined above are my personal perspective. Please do not hesitate to share yours! Any comments and suggestions are appreciated. Maybe you even have tangible or less tangible Genode-related plans as well? I would be happy to learn about them! The outcome of the discussion will eventually become the official road map for 2018, which I am going to announce in mid of January. Cheers Norman -- Dr.-Ing. Norman Feske Genode Labs https://www.genode-labs.com Â· https://genode.org Genode Labs GmbH Â· Amtsgericht Dresden Â· HRB 28424 Â· Sitz Dresden GeschÃ¤ftsfÃ¼hrer: Dr.-Ing. Norman Feske, Christian Helmuth

8 21

Constrained file descriptors
by Johannes Kliemann 05 Jan '18

05 Jan '18

Hi Norman, before Christmas we chatted about enabling the MMIO session on Linux. You said that you know a possibility to create constrained file descriptors (in such a way that accesses through this descriptor can only access a part of the file). I've done a second search but I couldn't find any useful information regarding this topic. Do you have any further, more specific, information about how to achieve this goal? Regards, Johannes

3 4

Sabre Lite imx6
by Baconicsynergy 02 Jan '18

02 Jan '18

Hello friends :) I am now the proud owner of the sabre lite imx6 SoC for the purpose of experimenting and running seL4, and am really eager to start building Genode scenarios. Unfortunately, the create_builddir tool only specifies imx53. What can i do to start working with genode on the sabre lite? Best regards, Joel Desermeau

3 2

Decentralized reproducible packages distribution system
by Michael Bideau 29 Dec '17

29 Dec '17

Hi everyone, I'm very new to Genode (discovered last week with seL4), so please forgive my lack of experience. I just wanted to bring you some information that might interest you, may be not today but soon (I hope). I stumble accross CHAINIAC <https://eprint.iacr.org/2017/648.pdf> (Usenix presentation video <https://www.usenix.org/conference/usenixsecurity17/technical-sessions/prese…>), a system to distribute software with many nice properties, that might be used for Debian packages one day. I copy-past Bryan Ford (co-author) description emailed at IEFT <https://www.ietf.org/mail-archive/web/suit/current/msg00154.html> : Abstract: Software-update mechanisms are critical to the security of modern systems, but their typically centralized design presents a lucrative and frequently attacked target. In this work, we propose CHAINIAC, a decentralized software-update framework that eliminates single points of failure, enforces transparency, and provides efficient verifiability of integrity and authenticity for software-release processes. Independent witness servers collectively verify conformance of software updates to release policies, build verifiers validate the source-to-binary correspondence, and a tamper-proof release log stores collectively signed updates, thus ensuring that no release is accepted by clients before being widely disclosed and validated. The release log embodies a skipchain, a novel data structure, enabling arbitrarily out-of-date clients to efficiently validate updates and signing keys. Evaluation of our CHAINIAC prototype on reproducible Debian packages shows that the automated update process takes the average of 5 minutes per release for individual packages, and only 20 seconds for the aggregate timeline. We further evaluate the framework using real-world data from the PyPI package repository and show that it offers clients security comparable to verifying every single update themselves while consuming only one-fifth of the bandwidth and having a minimal computational overhead. It uses blockchain, but it is an optional feature (as discussed in the Q&A at the end of the Usenix Conference <https://youtu.be/xpT6L8htINU?t=24m18s>) as long as you can check servers of the Cothority (if I have understood it well). It is written in Go (github repo <https://github.com/dedis/paper_chainiac>). On the subject of application portability/deployment, I know there is a lot of initiatives trying to normalize application packaging in a Linux kernel context, like OCI <https://www.opencontainers.org/>, Habitat <https://www.habitat.sh/>, Flatpak <https://flatpak.org/>, each targetting a different audience (cloud/desktop). It might be an interesting combination with Chainiac... I don't know. That was my $2 contribution. Hope it was not spam for you. I really want to help. I can start a wiki page if you want? But I will not be able to maintain it. Disclaimer : I'm absolutely not an expert neither about kernel/OS development, software distribution/package management, cyber security or any technology of this topic. But, until recently I've tryed to develop a generic desktop secure OS that isolate every process into a sandbox (using a Linux kernel, tools like firejail/bubblewrap/minijail providing linux-namespace and secomp-bpf, and inspiration from OpenWall for least priviledge policy. I've a prototype runing and working well but really too hacky. I've stopped because of not enought time and resources. Genode is an obviously much better approach! Congrats :-) I cannot wait to see my workstation runing a port of Qubes/SubGraph on Genode+seL4... Best wishes and happy new year. Michael Bideau, from France.

1 0

IPC messaging
by Nobody III 29 Dec '17

29 Dec '17

Currently, Genode has session interfaces for various use cases, but I'm unsure of which one to use for simple "send-and-forget" scenarios. The "Terminal" interface seems to be the best option currently available, but seems a little misleading. Should I use "Terminal" sessions for send-and-forget IPC, or is there a better option?

2 1

improved fs_rom
by Nobody III 29 Dec '17

29 Dec '17

While working on my own "Sculpt" scenario, I saw that the fs_rom server still doesn't allow using multiple directories as sources. Being able to separate the executables, libraries, and config files would be very helpful for organizing the filesystem and providing shared libraries to programs without exposing the configuration files as well. Is there a way to do this with the components currently available, or should fs_rom (or some other component) be modified to enable ROM file separation?

2 4

vfs named pipes
by Nobody III 27 Dec '17

27 Dec '17

Currently, there is no vfs plugin for named pipes. I can emulate this using two vfs instances and terminal_crosslink (using <terminal> vfs nodes), but is there a better/cleaner way of doing this?

1 0

pthread_main_np not implemented
by Steven Harp 27 Dec '17

27 Dec '17

After upgrading to 17.11, I noticed some of my libc+lwip using programs have started logging many warnings like: pthread_main_np_int: pthread_main_np called, not implemented This is observed with a fresh checkout (under x86_32/nova); so, I presume the cause is distinct from the similar warnings noted in #2312. Possibly related (?), during build, there were also quite a few warnings like: libports/src/lib/libc_lwip/plugin.cc:284:31: warning: âGenode::Env_deprecated* Genode::env()â is deprecated [-Wdeprecated-declarations] Genode::destroy(Genode::env()->heap(), context(fdo)); The programs actually seem to work, but the logs are "overly colorful". Perhaps there is some initialization that needs to be done differently? Any diagnostic hints appreciated. // Steve Harp

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users December 2017