171–180 of 195 posts
Would love to hear nix people take on this?
I want to run sandboxes based on Docker images that have Nix pre-installed. (Once the VM boots, apply the project-specific Flake, and then run Docker Compose for databases and other supporting services.) In theory, an easy-to-use, fully isolated dev environment that matches how I normally develop, except inside of a VM.
Would love to hear nix people take on this?
As a Nix user, I'm actually really excited to try this out. I want to run sandboxes based on Docker images that have Nix pre-installed. (Once the VM boots, apply the project-specific Flake, and then run Docker Compose for databases and other supporting services.) In theory, an easy-to-use, fully isolated dev environment that matches how I normally develop, except inside of a VM.
Earlier quoted context omitted.
> it's just sort of understood that a kernel LPE is going to break containers. I think it's generally understood that any sort of kernel LPE can potentially (and therefore is generally considered to) lead to breaking all security boundaries on the local machine, since the kernel contains no internal security boundaries. That includes both containers, but also everything else such a user separation, hardware virtualiz…
A large proportion of LPE vulnerabilities are in the nature of "perform a syscall to pass specially crafted data to the kernel and trigger a kernel bug". For containers, the kernel is the host kernel and now the host is compromised. For VMs, the kernel is the guest kernel and now the guest is compromised, but not the host. That's a much narrower compromise and in security models where root on the guest is already exp…
Earlier quoted context omitted.
> it's just sort of understood that a kernel LPE is going to break containers. I think it's generally understood that any sort of kernel LPE can potentially (and therefore is generally considered to) lead to breaking all security boundaries on the local machine, since the kernel contains no internal security boundaries. That includes both containers, but also everything else such a user separation, hardware virtualiz…
> hardware virtualization controlled by the local kernel In some architectures, kernel LPE does not break platform (L0/EL2) virtualization, https://news.ycombinator.com/item?id=44141164 L0/EL2 L1/EL1 pKVM KVM AX Hyper-V / Xen / ESX
Earlier quoted context omitted.
As a Nix user, I'm actually really excited to try this out. I want to run sandboxes based on Docker images that have Nix pre-installed. (Once the VM boots, apply the project-specific Flake, and then run Docker Compose for databases and other supporting services.) In theory, an easy-to-use, fully isolated dev environment that matches how I normally develop, except inside of a VM.
but dont they have overlapping requirements of solving "not works on my machine"
Nix, on the other hand, solves the problem of building reproducible environments... but making said environments safe for running untrusted code is left as an exercise for the reader.
How’s performance? What’s the overhead versus docker? Terraform or Pulumi integration on the horizon?
Wow. Just seeing this. I've not done proper benchmarking yet but rn we are lagging behind in file I/O for the OverlayFS impl
Overlays are always tough because docker doesn’t like you writing to the filesystem in the first place. The weapon if first result is deflection; tell them not to do it.
I had to put up with an old docker version that leaked overlay data for quite a while before we moved off prem.
Earlier quoted context omitted.
If you use macOS then it has a great sandboxing system built in (albeit, undocumented). Anthropic are starting to experiment with using it in Claude Code to eliminate permission prompts. Claude can choose to run commands inside the sandbox, in which case they execute immediately. I've thought about making one of these for other coding agents. It's not quite as trivial as it looks and I know how to do it, also on Wind…
The lack of documentation for that system is so frustrating! Security feature are the one thing where great documentation should be table stakes, otherwise we are left just wildly guessing how to keep our system secure! I'm also disheartened by how the man pages for some of the macOS sandboxing commands have declared them deprecated for at least the last five years: https://7402.org/blog/2020/macos-sandboxing-of-fold…
Is AI a special case? Maybe! I have some ideas about how to do AI sandboxing in a way that works more with the grain of macOS, though god knows when I'll find the time for it!
Earlier quoted context omitted.
> it's just sort of understood that a kernel LPE is going to break containers. I think it's generally understood that any sort of kernel LPE can potentially (and therefore is generally considered to) lead to breaking all security boundaries on the local machine, since the kernel contains no internal security boundaries. That includes both containers, but also everything else such a user separation, hardware virtualiz…
A large proportion of LPE vulnerabilities are in the nature of "perform a syscall to pass specially crafted data to the kernel and trigger a kernel bug". For containers, the kernel is the host kernel and now the host is compromised. For VMs, the kernel is the guest kernel and now the guest is compromised, but not the host. That's a much narrower compromise and in security models where root on the guest is already exp…
There is no inherent advantage to virtualization, the only thing that matters is the security and robustness of the privileged host.
The only reason there is any advantage in common use is that the Linux Kernel is a security abomination designed for default-shared/allow services that people are now trying to kludge into providing multiplexed services. But even that advantage is minor in comparison to modern, commonplace threat actors who can spend millions to tens of millions of dollars finding security vulnerabilities in core functions and services.
You need privileged manager code that a highly skilled team of 10 with 3 years to pound on it can not find any vulnerabilities in to reach the minimum bar to be secure against prevailing threat actors, let alone near-future threat actors.
Earlier quoted context omitted.
A large proportion of LPE vulnerabilities are in the nature of "perform a syscall to pass specially crafted data to the kernel and trigger a kernel bug". For containers, the kernel is the host kernel and now the host is compromised. For VMs, the kernel is the guest kernel and now the guest is compromised, but not the host. That's a much narrower compromise and in security models where root on the guest is already exp…
VM sandbox escape is just "perform a hypercall/trap to pass specially crafted data to the hypervisor and trigger a hypervisor bug". For virtual machines, the hypervisor is the privileged host and now the host is compromised. There is no inherent advantage to virtualization, the only thing that matters is the security and robustness of the privileged host. The only reason there is any advantage in common use is that t…
The advantage to virtualization is that the syscall interface is being implemented by the guest kernel at a lower privilege level instead of the host kernel at a higher privilege level.
Earlier quoted context omitted.
You can optimize a lot to start a Linux kernel in under a second, but if you're using a standard kernel, there are all manners of timeouts and poll attempts that make the kernel waste time booting. There's also a non-trivial amount of time the VM spends in the UEFI/CSM system preparing the virtual hardware and initializing the system environment for your bootloader. I'm pretty sure WSL2 uses a special kernel to avoid…
That's not what I'm asking about. I'm saying it takes a long time for it to even execute a single instruction, in the BIOS itself. Even for the window to pop up, before you can even pause the VM (because it hasn't even started yet). What you're describing comes after all that, which I already understand and am not asking about.
On the other hand, it could just as easily be something simple, like setting up hugepages or checksumming virtual hard disk image files.
Both are total guesses, though. Could be anything!