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Comment by wavemode | Hacker News Reader

> Nothing in the article discusses a parser or anything like a parser bug.

And it doesn't claim to. The article is titled "footguns" not "bugs". A footgun is just something that is easy to misuse due to unintuitive or unexpected behavior.

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> And it doesn't claim to.

Yes it does. The title is literally "Unexpected security footguns in Go's parsers". The article didn't identify a single footgun. This is just bad design.

The article links to CVEs directly caused by some of the less intuitive behavior here. I feel like that’s sufficient to qualify as a footgun

That title is clearly constructed to imply that Go's parsers are insecure. The text of the article isn't about parsers at all, and only tangentially about Go[1].

It's deliberately misleading clickbait. You know it. I know it. We all know it.

If you want to have a considered discussion about pitfalls with the use of automatic serialization paradigms across trust boundaries, I'm here for it. If you just want to flame about Go, get better source material. This one isn't the hill to stand on.

[1] Which, again, has a really first rate serialization story; but not one fundamentally different from any of a zillion others. Cooking data from untrusted sources is just plain hard, and not something that anyone (much less the author of this awful blog post) is going to solve with a serialization API.

I disagree.

It was a bad design choice to allow JSON keys with different capitalisation and to serialise all public struct members by default.

These decisions can easily result in the creation of an insecure system.

I don’t think the title is clickbait. You’re fixating on just one example in the post, but the others demonstrate a clear pattern: there are footguns in Go’s various parsers, including forms of malleability or flexibility that enable parser differentials.

This isn’t intended to be a ding against Go; it’s a universal problem across programming languages (otherwise there’d be no differentials at all). But they’re worth noting, and I think the post amply demonstrates their security relevance.

Of course it's about Go. They decided to build not just opt-out unmarshaling of objects, but fragile opt-out.

See eg rails' strong params for the opposite approach: opt-in.

I think you and I read a different article. For example, about treating JSON keys without case sensitivity:

> In our opinion, this is the most critical pitfall of Go’s JSON parser because it differs from the default parsers for JavaScript, Python, Rust, Ruby, Java, and all other parsers we tested.

It would be kind of difficult to argue that this is not about Go.

Don't get me wrong, I love Go just as much as the next person, but this article definitely lays bare some issues with serialization specific to Go.

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