Re:WebAssembly doesn’t make unsafe languages safe
by kllrnohj on Tuesday November 27, 2018 @12:03AM
(#18539555)
> I literally linked to the commit where V8 is indeed unanimously making that decision.
And for things where retpoline isn't needed it's unambiguously wrong (wrong in that runtime is slower than it should be for no gain). What are you not getting about that? They made a decision that when it's wrong it's still safe, but it's still going to be wrong for a non-trivial amount of users.
> Go read the WASM spec. [...] It just didn't make it into the MVP.
Yes, I know, that's why I said what I said. Which was correct and supported by both the spec and your statement just now...?
We're not talking about hypothetical future WASM, we're talking about WASM as it exists today and what problems it can/can't effectively handle.
I literally linked to the commit where V8 is indeed unanimously making that decision. If you clear the indirect branch table when transitioning to and from all untrusted programs, what's your threat model again?
> I get WASM doesn't want to include malloc/free, but the problem is it didn't include paging-based allocation APIs. It used a nonsense linear growth heap design that doesn't match anything about how memory works on any platform and has been obsolete for 20+ years.
Go read the WASM spec. It's explicitly is designed for multiple linear regions, just how mmap works. It just didn't make it into the MVP.