[cabfpub] Proposed new ballot on IP Addresses in SANs

Ryan Sleevi sleevi at google.com
Thu Apr 21 13:41:56 UTC 2016

On Thu, Apr 21, 2016 at 6:30 AM, Jody Cloutier <jodycl at microsoft.com> wrote:

> As a Forum member, Google is certainly within its purview to vote no,
> then. Let's put it to a vote and see where it comes down.

It is truly unfortunate to see you encouraging a vote on a practice with
known and quantifiable interoperability and security risks.

Interoperability risks: This violates RFC5280. This penalizes
implementations that properly implement RFC5280 - such as Mozilla Firefox,
which enforces that a dNSName properly conforms to the RFCs (with a limited
exception for certain characters for legacy reasons, despite being
forbidden by the BRs).

Security risks: Such addressing defeats the "Technically Constrained
Sub-CA" provision of the BRs, allowing an issuing CA to bypass iPAddress
nameConstraints for clients which do not enforce that the reference
identifier (RFC 6125 terminology) is a domain. This is the majority of TLS
clients out there, whose only protections are the explicit prohibitions of
this behaviour in the Baseline Requirements.

While I can appreciate the need and desire to support downlevel Windows
clients, I offered a clear and concrete solution that avoids these risks
entirely, while meeting that need. To suggest there is no interest in
addressing these, or that such risks are unimportant - which is what a
ballot would effectively be, based on the information presently provided -
would be a step back for the Forum, and an unfortunate statement for the
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