### PART 2 (as the comment was too long for the system here) ###:

> > One should never over promise on security! Java had to learn this the hard way over many years (as their sandbox had have holes in the past, and was also almost impossible to correctly configure).

> To reiterate, WASM incorporated these details from the outset, to the point that providing useable WASM VMs outside of browsers years to come about.

Could it be that you just again confused "sandboxing" and memory safety?

The problem with the JVM sandbox (and most of the time other VM languages) isn't memory safety!

There have been such bugs here and there, sure. In the JS VMs, the WASM WMs (like pointed out in the above linked paper), and also the JVMs.

But those bugs are the usual implementation bugs.

Once again, this is not relevant to the questions here. Memory safety is not a "sandbox"!

> WASI is the result of carefully adding back in things like FS access using capabilities and other techniques to keep it sandboxed.

What "sandbox" are you talking about?

There is only one WASI implementation that offers a extremely simple FS access filter. (And Wasmer, which we're taking about here, does not even have that, as I see it).

Capability security? Where is this implemented?

One again: I don't talk about what people dreamed up! I'm asking for the status quo.

> This is harder, and introduces more surface area to violate WASM's sandboxing.

Yes, that's the point.

Having a cage that does not let anything through is easy. Just build massive walls without windows and doors. Nothing can get out. Nothing can get in…

But such a cage is almost useless.

So the interesting part starts when a thing in the cage needs to talk to the outside world!

"Solving" the "trivial" problem is indeed easy.

Now show me how you solve the real problem!

But to my knowledge there is nothing there. Nothing. (Besides promises and cool sounding plans for some distant future).

> However WASI seems well thought out so far.

Yes, "thought out". But not implemented!

BTW: They did not come up with anything new here.

Capability security is at least around 40 years old.

The point is: Nobody ever implemented this outside of academia.

We have just now the first steps in that direction.

But that are at best beta versions of tech form the future…

As it stands today: WASM does not have any meaningful sandbox. (Memory safety is not a sandbox! It's "just" a prerequisite to be able to implement a sandbox. But it's not one by itself, and a feature _every_ VM runtime provides).

Even containers will give you more sandboxing based on the (by now) rich features of Linux namespaces. (Still nobody considers this a serous sandbox on which you could bet your ass. That's why we run containers in VM; because that's the only—more or less—reliable sandbox we currently have; as our OSes and hardware still don't provide capability security features).

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Don't get me wrong though.

I do think that the whole "linear memory" idea for memory safety is indeed a very good one.

It's so good, I think this should be implemented on the HW level! (Or at least in a first step on the OS level).

But "really safe memory cages" aren't sandboxes.

Without capability security on top this does not provide any meaningful improvement over what we have already since decades.

But capability security isn't something that you can just to piggyback after the fact. Everything, form the languages used and their libs, up through the OS and VM layers need to be explicitly build with this mechanism in mind. We're still light years away form having such infrastructure!

But what the WASM people present is some fantasy world where all this is already in place.

Given how aggressive those obvious lies are pushed I can't come to any other conclusion than that there is a lot of bad faith behind this campaigns. "Someone" tries to push by all means their VM tech into the market. Even they're leaking around 20 years behind the next competitor. This whole thing is a disgusting marketing war.

And to be honest I'm quite scared how effective this ultra aggressive marketing is even it's almost completely based on highly over promised stuff up to, in its extreme, blatant lies. I hope the person I'm talking to here isn't part of this marketing effort. And people reading this start to ask themself the "right questions" finally ;-).