[GnoVM] Gas system doesn't catch infinite loops

[leohhhn]

Description

Credit to @odeke-em, #3417

package hello

func main() {
  for {}
  println("hello world")
}

An ABCI query or a MsgCall call to this Render function will make the node non-responsive until the caller's context deadline is exceeded, posing a DOS attack vector. With gnokey, the terminal hangs until the gnokey context is exceeded, and with gnoweb, the page trying to render the realm also hangs, until gnoweb's builtin timeout kicks in and reports an internal problem.

This is obviously not caught with the gas system in either cases.

cc @thehowl @piux2

[n2p5]

Random thought here, and a bit of a continuation of a conversation with @mvertes that he and I had in October. If feels like something like the eBPF verifier pattern could be really useful for us.

https://docs.ebpf.io/linux/concepts/verifier/

for context eBPF allows users to extend core kernel functionality, so runtime safety measures (like no infinite loops) are part of the verification process.

[thehowl]

FWIW this is the same as #3563. @kristovatlas Which one should we close?

[petar-dambovaliev]

@Kouteki
During the meeting it was established that this issue is part of the work @mvertes is doing on recursivity.