API doc: "When the value is 1, the certificate must contain a Common Name field, but it doesn't matter what name it says. (This is not ordinarily a useful setting)."

[emphasis mine] It's hard to get clearer than that.

http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTS...

"Here's an option that you could reasonably expect to be boolean. And lo! the code appears to work if you treat it as a boolean. But, just to mess with you, I introduced an apparently useless option to handle the 'true' case in that boolean, and introduced an 'even truer' value that does what you expected".

This is simply a terrible, dangerous design. It is, like I said on Twitter today, a vulnerability in Curl, and one that should be fixed. The option expressed today by VERIFYHOST=1 should instead be the case when VERIFYHOST=-1 or VERIFYHOST=666. Meanwhile, VERIFYHOST=1 should, tomorrow if possible, do exactly what VERIFYHOST=2 does today.

The point of yours that I addressed was: "that VERIFYHOST=1 exists primarily to give people the feeling of having configured SSL/TLS well without making them actually do that."

Put simply: It does not exist primarily for that purpose.

I can't make it any clearer than that.

I'm kidding... I think.

You fail to provide any proof for that statement. The API doc merely states what the setting does, it says absolutely nothing about about its purpose, and neither do you.

> The default value for this option is 2.

In other words, there is absolutely no issue here. It does the right thing out of the box.

That's because experience shows if things are "grey" then someone can almost certainly break in.

It will only break servers and scripts that currently operate under a false sense of security. The maintainer should file a CVE, push the fixed version and let the distros sort out the rest. And he should do it ASAP.

Empirically, 0/1/2 either means no/yes/yes-and-something-obscure-on-top-of-that, or, worse, as in this case, no/kind-of-but-not-really/yes.

  enum Bool { 
      True,
      False,
      FileNotFound
  };