A Slint fanboy from Berlin.

  • 0 Posts
  • 55 Comments
Joined 1 year ago
cake
Cake day: June 12th, 2023

help-circle


  • When I last checked (and that is a long time ago!) it ran everywhere, but did only sandbox the application on ubuntu – while the website claimed cross distribution and secure.

    That burned all the trust I had into snaps, I have not looked at them again. Flatpaks work great for me, there is no need to switch to a wannabe walled garden which may or may not work as advertised.






  • Plugins are a code execution vulnerability by design;-) Especially with binary plugins you can call/access/inspect everything the program itself can. All UI toolkits make heavy use of plugins, so you can not avoid those with almost all UI applications.

    There are non-UI applications with similar problems though.

    Running anything with network access as root is an extra risk that effects UI and non-UI applications in the same way.


  • Usig anything as root is a security risk.

    Using any UI application as root is a bigger risk. That’s because every UI toolkit loads plugins and what not from all over the place and runs the code from those plugins (e.g. plugins installed system wide and into random places some environment variables point to). Binary plugins get executed in the context of the application running and can do change every aspect of your program. I wrote a small image plugin to debug an issue once that looked at all widgets in the UI and wrote all the contents of all text fields (even those obfuscated to show only dots in the UI) to disk whenever some image was loads. Plugins in JS or other non-native code are more limited, but UI toolkits tend to have binary plugins.

    So if somebody manages to set the some env vars and gets root to run some UI application with those set (e.g. using sudo), then that attacker hit the jackpot. In fact some toolkits will not even bring up any UI when run as root to avoid this.

    Running any networked UI application as root is the biggest risk. Those process untrusted data by definition with who knows what set of plugins loaded.

    Ideally you run the UI as a normal user and then use sudo to run individual commands as root.


  • The one thing you can learn from sysv init isnthat asking devs to pitncode into their programs or into starter scripts does not work. They will not bother: Those will notmworkmcross platform.

    So you need to cebtralize that task. You can either write a wrapper program that sandboxes starts applications in a sandbox or do that whereever the programs as are started anyway.

    A separate sandboxing app that starts services complicates configuration: You basically need to configure two things the starter and the service. On the up-side you have the sandboxing code separate. Merging the sandboxing into the program starting the service makes configuration simple but adds moremcode into the the starter program.

    So it is basically a decision on what you value more. Systemd decided to favor simpler configuration. The cost for adding the sandboxing is small anyway: It’s all Linux kernel functionality that does need a bit of configuration to get rolling, with much of that code being in the systemd-init anyway: It uses similar functionality to actually separate the processes it starts from each other to avoid getting confused by programs restarted and thusnchanging PIDs – something still a thing in many other inits.

    I am convinced that making sandboxing easy does a lot formits adoption. No admin will change the entire startup configuration to add a sandboxing wrapper around the actual service. It is way more likely for them to drop in a override file with a couple of lines and without any problems when upstream changes command line options.




  • Censorship is about you being limited in the actions you can take to express yourself. It is not about cushioning you from the consequences of those actions from the people around you.

    You obviously were allowed to take action: The contents was apparent upon on a forum and here as well. People reacted to your actions: Admins removed your contents and blocked you and I am telling you that your understanding of wayland as well as politics is limited.

    Deal with it.



  • Yes, wayland by design does not let random applications grab events intended for other applications nor does it let random applications take screenshots at any point in time showing other applications screens. This requires applications to do screen sharing differently, and it indeed breaks random applications sending events to random other applications. That is basically all you wail about and an absolutely necessary property of any sensible system and it is very embarrassing that it took so long to get this.




  • The point of using the TPM is that it does not unlock the drive unless it has a certain set of software is loaded in a certain sequence on the machine with that specific TPM chip.

    So if somebody breaks grub and makes it load a shell, then that results in different software loaded (or at least loaded in a different sequence) and will prevent the TPM to unlock the system. The same is true if somebody boots from a rescue disk (different software loaded) or when you try to unlock the disk in an unexpected phase of the boot process (same software but different sequence of things loaded, e.g. after boot up to send the key to some server on thr network. The key is locked to one TPM, so removing the drive and booting it in a different machine also does not work.

    The TPM-locked disk is pretty secure, even more so than that USB idea of yours – if the system you boot into is secure. It basically stops any attacker from bringing extra tools to help them in their attack. All they have available is what your system has installed. Do not use auto-login or run some root shell in some console somewhere…


  • But if the key is fully wrench-safe inside the TPM. You do not know it, you can not get convinced to give it up – even after repeated wrench use.

    Of course the recovery key that typically goes with it and you logging password is not wrench safe, so that does not protect the system fully, while getting you a matching set of broken kneecaps.


  • The idea behind TPM-locked boot is that you can boot into your system unattended, but it stops booting into any other system. Typically no password is needed, but you can also assign an additional (non-user) password if you want.

    This is nice if you trust your system to be basically secure. Nothing else can access its filesystems, so no external tool can be used to break into it. Rescue disks can not access any data without knowing a special rescue key – so make sure to set one up! A nice side effiect is that the key is only available while setting up disks in the initrd and totally inaccessible at any other time. That makes it very hard to extract the password once the system is running.

    You can encrypt the home directories of users using other services like systemd-homed. That will prevent anyone from accessing any data in the user’s directory while that user is logged out. Homed will basically use your password to unlock your disk and if that works, then the password is accepted. So you do not need that user to be listed in the traditional /etc/passwd file, which is useful as you can just copy the users homedir image file onto another system to move a user account over.