> If you want to claim that a language is memory-unsafe, POC || GTFO.

There's a POC right in the post, demonstrating type confusion due to a torn read of a fat pointer. I think it could have just as easily been an out-of-bounds write via a torn read of a slice. I don't see how you can seriously call this memory safe, even by a conservative definition.

Did you mean POC against a real program? Is that your bar?

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tptacek 5 days ago | parent [-]

You need a non-contrived example of a memory-corrupting data race that gives attackers the ability to control memory, through type confusion or a memory lifecycle bug or something like it. You don't have to write the exploit but you have to be able to tell the story of how the exploit would actually work --- "I ran this code and it segfaulted" is not enough. It isn't even enough for C code!

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codys 5 days ago | parent [-]

The post is a demonstration that a class of problems: causing Go to treat a integer field as a pointer and access the memory behind that pointer without using any of Go's documented "unsafe.Pointer" (or other documented as unsafe operations).

We're talking about programming languages being memory safe (like fly.io does on it's security page [1]), not about other specific applications.

It may be helpful to think of this as talking about the security of the programming language implementation. We're talking about inputs to that implementation that are considered valid and not using "unsafe" marked bits (though I do note that the Go project itself isn't very clear on if they claim to be memory-safe). Then we want to evaluate whether the programming language implementation fulfills what people think it fulfills; ie: "being a memory safe programming language" by producing programs under some constraints (ie: no unsafe) that are themselves memory-safe.

The example we see in the OP is demonstrating a break in the expectations for the behavior of the programming language implementation if we expected the programming language implementation to produce programs that are memory safe (again under some conditions of not using "unsafe" bits).

[1]: https://fly.io/docs/security/security-at-fly-io/#application...

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tptacek 5 days ago | parent [-]

The thread you're commenting has already discussed everything this comment says.

If you've got concerns about our security page, I think you should first take them to the ISRG Prossimo project.

https://www.memorysafety.org/docs/memory-safety/

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codys 5 days ago | parent [-]

In this thread I linked the fly.io security page because it helps us establish that one can talk about _languages_ as being memory safe specifically, which is something it seems you're rejecting as a concept in the parent and other comments.

(In a separate comment about "what do people claim about Go anyhow", I linked the memorysafety.org page, but I did not expect it to help in getting you to the understanding that we can evaluate programming languages as being memory safe or not, where something from the company where someone was a founder seemed more likely to get a person to reconsider the framing of what we're examining)

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tptacek 4 days ago | parent [-]

Huh? No, I'm not. Go is a memory-safe programming language, like Java before it, like Python, Ruby, Javascript, and of course Rust.

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zozbot234 4 days ago | parent [-]

So you're saying nobody cares about actual memory safety in concurrent code? Then why did the Swift folks bother to finally make the language memory-safe (just as safe as Rust) for concurrent code? Heck why did the Java folks bother to define their safe concurrency/memory model to begin with? They could have done it the Golang way and not cared about the issue.

	▲	tptacek 4 days ago \| parent [-]
		I don't know why you're inventing things for me to have said.