RFR: 8281561: Disable http DIGEST mechanism with MD5 by default

[Michael McMahon]

On Fri, 4 Mar 2022 09:37:21 GMT, Michael McMahon <michaelm at openjdk.org> wrote:

> Hi,
> 
> Could I get the following change reviewed please, which is to disable the MD5 message digest algorithm by default in the HTTP Digest authentication mechanism? The algorithm can be opted into by setting a new system property "http.auth.digest.reEnabledAlgs" to include the value MD5. The change also updates the Digest authentication implementation to use some of the more secure features defined in RFC7616, such as username hashing and additional digest algorithms like SHA256 and SHA512-256.
> 
> - Michael

> > > I considered that and implemented it that way at the start, but what you would end up with then is users running their code with something like: -DdisabledAlgNames=""
> > > I find that style leads to a much less explicit "opting in" than by making the user explicitly identify the deprecated algorithm by name.
> > 
> > 
> > Right - but it would also allow users to opt-in to disable more algorithms by listing them in the property
> 
> In practical terms, the only other likely candidate there is SHA-1. If that weren't the case, I'd disagree with your point.
> 
> So, maybe, we could have a 2nd net property with the default disabled algorithms and in net.properties we identify MD5 only for now. Users could add to that list if they want or even specify it on the command line. I think it's potentially confusing, but maybe there is a case for adding to the disabled list. I need to think about a way to do this without subvertng the point about making the user explicitly opt in.



> > > I considered that and implemented it that way at the start, but what you would end up with then is users running their code with something like: -DdisabledAlgNames=""
> > > I find that style leads to a much less explicit "opting in" than by making the user explicitly identify the deprecated algorithm by name.
> > 
> > 
> > Right - but it would also allow users to opt-in to disable more algorithms by listing them in the property
> 
> In practical terms, the only other likely candidate there is SHA-1. If that weren't the case, I'd disagree with your point.
> 
> So, maybe, we could have a 2nd net property with the default disabled algorithms and in net.properties we identify MD5 only for now. Users could add to that list if they want or even specify it on the command line. I think it's potentially confusing, but maybe there is a case for adding to the disabled list. I need to think about a way to do this without subvertng the point about making the user explicitly opt in.

Thinking about it again, I wonder if we should just deprecate SHA-1 at the same time. I think there will be less compatibility impact than with MD5, and it's basically broken as well. I don't see a reason to opt out of other algorithms at this time.

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PR: https://git.openjdk.java.net/jdk/pull/7688