Rustaceans at the border [LWN.net]

Rustaceans at the border

Posted Apr 15, 2022 0:55 UTC (Fri) by mjg59 (subscriber, #23239)
In reply to: Rustaceans at the border by IanKelling
Parent article: Rustaceans at the border

I just want to be clear on this - you'll download kernel source code from the internet and type "make", resulting in a great deal of code running on your system, but you're not ok with javascript running inside a strongly sandboxed environment?

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Rustaceans at the border

Posted Apr 15, 2022 8:39 UTC (Fri) by tux3 (subscriber, #101245) [Link] (3 responses)

Presumably a possible defense for the more general version of this position is that the review process is very different, between web pages in general and the kernel.

While I personally run most JavaSscript without a second though, some websites that are not crates.io sometimes run undesirable JS - cryptominers, supercookies, what have you. Sometimes there is third-party JS code that has clever ways of escaping the sandboxes.
I am told Firefox's content process lost connection to the X11 server just a month ago. Although the sandbox is improving as well, hardness may sometimes be a relative thing.

In contrast, I will trust Debian to update many millions of lines of code straight from the internet into a running system, much of it which could enter my $HOME.
If the kernel were to pull in more external libraries, like it did with zstd, there's more than a couple git remotes that I'd feel I could pull from without being gifted any crypto miner or other code that might try to poke at a sandbox.

Rustaceans at the border

Posted Apr 15, 2022 8:49 UTC (Fri) by mjg59 (subscriber, #23239) [Link] (2 responses)

I have no reason to believe that kernel code gets significantly more review than crates.io does - I agree that the web as a whole doesn't meet that bar, but frankly most software I pull from Debian has also had much less review than the kernel does (https://lists.debian.org/debian-devel/2003/02/msg00771.html is an example of this not going well) so it feels like what's missing is a way to express what level of trust I place in any provider of code I end up executing rather than just to assert that websites that use Javascript are unacceptable .

Rustaceans at the border

Posted Apr 15, 2022 9:08 UTC (Fri) by tux3 (subscriber, #101245) [Link] (1 responses)

I agree with that. As for crates.io, I have respect for the work they do and I'm happy to run their code (though I have not read it).
This may be getting off-topic, but now I'm curious if you have anything specific in mind when you write about expressing levels of trust — would that look like further sandboxing?

Rustaceans at the border

Posted Apr 15, 2022 9:27 UTC (Fri) by mjg59 (subscriber, #23239) [Link]

Great question! I spent a while looking into whether it was feasible to apply different LSM profiles (SELinux/Apparmor/whatever) to dpkg depending on where the package was downloaded from, and unfortunately the architecture doesn't make that terribly possible. From the web perspective, I think that probably comes down to extension-level handling at the moment? In an ideal universe we'd have infrastructure to tie any given piece of javascript back to an upstream repo and make a trust decision based on things like licensing and review assurances, but that feels like kind of a lot of work.

Rustaceans at the border

Posted Apr 15, 2022 13:51 UTC (Fri) by IanKelling (subscriber, #89418) [Link]

Hah good point. I do generally try to also run make within a sandbox too though. Websites should not requiring people to download and run a program to simply read a page of text. Crates.io is almost entirely used for text that could be simple html.

Rustaceans at the border

Posted Apr 19, 2022 8:28 UTC (Tue) by LtWorf (subscriber, #124958) [Link] (12 responses)

> but you're not ok with javascript running inside a strongly sandboxed environment?

The fact that there is a CVE a day or so for chromium and firefox contraddicts your statement about "strongly sandboxed".

Rustaceans at the border

Posted Apr 19, 2022 8:50 UTC (Tue) by mjg59 (subscriber, #23239) [Link] (11 responses)

Very few of those CVEs involve sandbox escapes.

Rustaceans at the border

Posted Apr 19, 2022 9:29 UTC (Tue) by LtWorf (subscriber, #124958) [Link] (10 responses)

Only one is needed though.

Rustaceans at the border

Posted Apr 19, 2022 9:45 UTC (Tue) by mjg59 (subscriber, #23239) [Link] (9 responses)

Sure, but only one local privilege escalation bug in Linux is needed for any non-Javascript attack vector and there's more of those than there are Chrome sandbox escape chains.

Rustaceans at the border

Posted Apr 19, 2022 13:43 UTC (Tue) by LtWorf (subscriber, #124958) [Link] (8 responses)

But I trust anything coming from apt much more than anything coming from some website.

Rustaceans at the border

Posted Apr 19, 2022 13:59 UTC (Tue) by rahulsundaram (subscriber, #21946) [Link] (7 responses)

> But I trust anything coming from apt much more than anything coming from some website.

The conversation isn't really about what you personally trust but what ought to be considered trusted by people and that should be based on empirical data. For the most part, distributions don't vet code from upstream for security issues and sometimes distribution specific patching can even introduce security holes (A notorious example is https://www.debian.org/security/2008/dsa-157).

Rustaceans at the border

Posted Apr 19, 2022 14:01 UTC (Tue) by farnz (subscriber, #17727) [Link] (6 responses)

Your link is truncated - I'm guessing you mean this OpenSSL predictable RNG security advisory?

Rustaceans at the border

Posted Apr 19, 2022 14:30 UTC (Tue) by rahulsundaram (subscriber, #21946) [Link] (5 responses)

> Your link is truncated - I'm guessing you mean this OpenSSL predictable RNG security advisory?

Correct. Thanks

Rustaceans at the border

Posted Apr 19, 2022 16:58 UTC (Tue) by amacater (subscriber, #790) [Link] (4 responses)

This is a favourite stick to drag up to beat Debian with: what's more interesting is to actually go back and realise what happened when it came to light. The work by Luciano Bello was first class: Debian's response was clear and relatively immediate - explain the problems with OpenSSL and thereby OpenSSH fully, create a tool to deny-list problem keys, explain what needed regenerating and why.

The mistake came as a result of actually querying with the upstream maintainers what should be done and doing it inappropriately once too often. I haven't seen other incidents handled as well by other teams and other distributions - let alone by commercial software. It's worth looking at as something being handled well at the time and in retrospect, not necessarily trotted out at every opportunity 14 years later

Rustaceans at the border

Posted Apr 19, 2022 17:36 UTC (Tue) by rahulsundaram (subscriber, #21946) [Link] (3 responses)

> This is a favourite stick to drag up to beat Debian with

As I specifically noted already, it was just an example of a distribution specific vulnerability that is more well known (and it has some significance due to OP's reference to apt but mostly incidental). Your defensive reaction to that specific example does nothing to address the broader point. Replace that example with another distribution example if it helps you, here you go:

https://nvd.nist.gov/vuln/detail/CVE-2007-5962

We can certainly find more across distributions since everytime backporting or distribution specific patching happens (even as simple as a permissions change in the filesystem), there is deviations from upstream that introduces some potential risk of bugs including security vulnerabilities that don't exist upstream. So the broader point is that humans are infallible and occasions make mistakes (not even counting malicious attackers) and we shouldn't automatically rely on distributions to provide us a better security compared to well vetted upstream projects. Atleast in some cases, they do worse.

Rustaceans at the border

Posted Apr 19, 2022 17:39 UTC (Tue) by rahulsundaram (subscriber, #21946) [Link]

Correction: humans are not infallible.

Rustaceans at the border

Posted Apr 19, 2022 18:11 UTC (Tue) by amacater (subscriber, #790) [Link] (1 responses)

Well vetted upstream projects is the difficulty. "With enough eyeballs, all bugs are shallow" - not necessarily if the eyelids (or codebases) happen to be effectively closed ... and see the discussions round the security of Chrome/Chromium regularly, for example.

The case of Rust in the kernel is similar to the problems of vendored code necessary to keep some ecosystems running: Node is the obvious one that causes problems to Debian and others.

It's possible that there's just an instinctive awareness of potential problems to come.
There's _so_ much code there that's intertwined and impenetrable and we've all been subject on occasion to being force-marched forwards by large scale change in someone else's ecosystem that we can't control - see, for example init system flamewars or Python 2 -> Python 3 (or a.out to ELF if your memory is long enough).

Rustaceans at the border

Posted Apr 19, 2022 18:28 UTC (Tue) by rahulsundaram (subscriber, #21946) [Link]

> Well vetted upstream projects is the difficulty

To be clear, the original context here was visiting crates.io website compared to installing a distro package.

> The case of Rust in the kernel is similar to the problems of vendored code necessary to keep some ecosystems running

Vendored code already exists in the Linux kernel. The Rust mechanisms for tracking vendoring is strictly better than the ones we have for vendored C based projects in the kernel.