Re: [TLS] Question about draft-thomson-tls-sic
Adam Langley <agl@imperialviolet.org> Wed, 24 July 2019 01:15 UTC
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From: Adam Langley <agl@imperialviolet.org>
Date: Tue, 23 Jul 2019 18:15:10 -0700
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To: Watson Ladd <watson=40cloudflare.com@dmarc.ietf.org>
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Subject: Re: [TLS] Question about draft-thomson-tls-sic
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On Tue, Jul 23, 2019 at 5:23 PM Watson Ladd <watson= 40cloudflare.com@dmarc.ietf.org> wrote: > Suppose the following sequence of events happen: > > 1: A CA uses a new intermediate for reasons (no longer cross-signing, etc.) > 2: A site gets a certificate from the new intermediate. > 3: An older firefox version connects and thinks it knows all the > certificates in the world. > > This would seem to break and it wasn't clear to me how this would be > handled. Though as Martin points out this extension is merely codification > of an occasional practice, so maybe this case does actually work out. > I think the client would have to fall back and retry the TLS connection without requesting that intermediates be omitted. In general, I think this is the only reliable answer as AIA-chasing doesn't always work. (Either the AIA server can be down, or the chain can be from a private CA that doesn't support AIA.) Cheers AGL
- [TLS] Question about draft-thomson-tls-sic Watson Ladd
- Re: [TLS] Question about draft-thomson-tls-sic Adam Langley