Re: [websec] Decouple HSTS's two orthogonal effects?

[Tom Ritter <[e-mail]>]

On Tue, Mar 29, 2011 at 4:58 PM, Adam Barth <[e-mail]> wrote:
> There's no coupling between HSTS and the particular algorithm a UA
> uses to verify certificates.  The UA is free to use whatever
> verification mechanism it desires.

This is good, but perhaps some clarification to the draft would be in order:

Section 2.2 states:

   2.  The UA terminates, without user recourse, any secure transport
       connection attempts upon any and all secure transport errors or
       warnings, including those caused by a site presenting self-signed
       certificates

Knowing that HSTS allows any validation method a posteriori allows you
interpret this correctly - that self-signed certs *may* be allowed
under HSTS, if the user has added them to their store.  But without
that, it may be interpretted incorrectly - that no self-signed certs
would be allowed.  Furthermore, I'm not sure, but "any and all secure
transport errors or warnings" may be ambiguous.  I don't know if it's
an existing standard to enter a warning or error state in event of
(for example) a revocation check failure - although we do know that
most browsers do not present any warning or error.  There's more on
that in Adam Langley's thread.   If HSTS does not define whether or
not a revocation check failure is an error condition, I think it
should.

Also Section 9 recommends distributing root CA certs to users'
browsers, and does not mention the possibly of distributing the leaf
certs instead.  Less related, but I prefer to trust organizations leaf
certs individually than their root cert.

-tom