Robert Haas wrote:
>> Perhaps the best method would actually be to match only "*." at the
>> beginning of the CN for now, and see if people complain? I would much
>> like someone who knows more about what would be reasonable to speak up
>> here, but it seems we don't have anybody here who knows...
>
> I would encourage you to adopt a solution where * matches only a
> single pathname component. This seems to be the intention of both
> RFC2818 and RFC2595. It is also the behavior of IE7; FF2 seems to
> deviate from the spec.
>
> http://www.hanselman.com/blog/SomeTroubleWithWildcardSSLCertificatesFireFoxAndRFC2818.aspx
If you look at the wiki page mentioned upthread,
http://wiki.cacert.org/wiki/WildcardCertificates, you will see that it
seems like *all* products other than IE are converging on the non-IE
behavior. Which would be an argument for implementing that method.
> There are several other advantages of this approach that seem worth mentioning:
>
> 1. If you make it match a single pathname component now, and later
> decide that you were wrong and change your mind, it is guaranteed not
> to break any working installations. The reverse is not true.
True.
> 2. I can't see any possible way that matching a single component could
> create security holes that would be eliminated by matching multiple
> components, but I'm more skeptical about the other direction. What
> about the old DNS hack where you create a DNS record for
> example.com.sample.com and hijack connections intended for example.com
> made by people whose default DNS suffix is sample.com? There may be
> reason to believe this isn't a problem, but matching less seems like
> it can't possibly be a bad thing.
Right, but that's all about being careful not to give out certs like
"*.postgres.*".
> 3. It would be truly bizarre if www*.example.com matched
> www17.some.stuff.in.the.middle.example.com. (That having been said, I
> wouldn't worry about wildcards intended to match part of a component
> too much. I suspect that it's an extremely rare case, and we can
> always add support later if there is demand for it. Not worrying
> about this now will help keep the code simple and free of bugs, always
> good in a security-critical context.)
Yeah.
I think I agree with the idea that we should match wildcards only at the
beginning of the name *for now*, and then see what people actually
request :-) I'm less sure about the single-pathname-component part, but
the argument around backwards compatible is certainly a very valid one..
//Magnus
