Subject: Re: [TLS] Ecdsa-sig-value in TLS 1.3 – need for erratum?

From: Dan Brown <[email-masked]>
Date: Tue, 1 Oct 2019 23:32:03 +0000

Does reading Ecdsa-sig-value need a full DER parser?
The new syntax does not rely on a buggy parser, as far as I know.  
The biggest bug is in the old syntax, which is not extensible.
Use a valid DER parser plus new syntax to accept signatures, and all old syntax signatures will accepted, right???
Is it possible to do better with a non-extensible syntax?
The only breakdown is the old syntax parsers receiving the extensions, right?
That's the only place a lax parser would help.

  Original Message  
From: Peter Gutmann
Sent: Tuesday, October 1, 2019 6:15 PM
To: Hubert Kario; Dan Brown
Cc: [email-masked]
Subject: Re: [TLS] Ecdsa-sig-value in TLS 1.3 – need for erratum?

Hubert Kario <[email-masked]> writes:

>a lax DER parser sounds like an oxymoron to me... :)

That's why I assumed it was an accident/error. Writing a spec that relies on
buggy parser implementations in order to work is asking for trouble.

Peter.