Sean Conner sean at conman.org
Thu Apr 8 03:35:41 BST 2021
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It was thus said that the Great nervuri once stated:
On Mon, 2021-04-05, Sean Conner wrote:
The updated protocol (only) specification is now up and can be read at:
https://gitlab.com/gemini-specification/protocol/-/blob/master/specification.gmi
Thank you. A few thoughts:
I recommend making each change in a separate commit, to make it easier
to isolate and comment on. In a huge diff like this [1] it's easy to
miss small, but important changes.
Further changes should be less massive. I know this change is large, butonly because I felt it easier to just rewrite the document from scratch thantry to adjust the existing one.
[1]
https://gitlab.com/gemini-specification/protocol/-/commit/0235100151b57d9f5c3384acdacb4ad9986f7ae4?expanded=1&view=inline
The use of an existing TLS library SHOULD be used, but because not all
existing TLS libraries support TLS 1.3, then at this time (2021),
implementations MUST support TLS version 1.2 or higher.
You probably meant to start with "An existing TLS library SHOULD be
used", but what does this actually mean? Existing as of when? If
someone makes a new TLS library, it will also exist. Also, many
libraries are abandoned, so it will never be the case that "all existing
TLS libraries" will support TLS 1.3, or even 1.2.
Okay, I reworked this paragraph:
At the time of writing (2021), not all existing TLS libraries support TLS 1.3, but a majority (all?) do support TLS 1.2, thus TLS 1.2 is the minimum required version. Implementations MUST support TLS SNI (Server Name Indication), and servers MUST use the TLS close_notify implementation to close the connection. Clients SHOULD NOT close a connection by default, but MAY in case the content exceeds constraints set by the user.
I don't think the final Gemini specification should mention libraries at
all. They may be ok as a temporary justification for why TLS 1.2 is in
the spec, but let's see if we can get more clarity on this: what exactly
are we waiting for before TLS 1.3 becomes the minimum version? Support
in BearSSL (which may never be added)? Support in X% of clients and Y%
of servers? Hard to say, isn't it?
One reason was the use of LibreSSL, which (until relatively recently) onlysupport TLS 1.2, and there were several large sites using LibreSSL(including mine, until I switched to using OpenSSL and libretls). Also,stats [1] show that some 21% of Gemini sites still use TLS 1.2. Personally,I think that once this falls below 5% (or greater than 95% of all sitessupport TLS 1.3) we can revisit this decision.
TLS 1.2 will send the server name and the client certificate (if used)
in the clear
TLS 1.3 also sends the server name (SNI) in the clear, unless ECH/ESNI
is used. The issue here is that TLS 1.2 is not compatible with
ECH/ESNI. But even with TLS 1.3, public keys need to be put in DNS in
order for ECH/ESNI to work, so it will probably not be a mainstream
feature (although it should be encouraged).
This, I did not know. I'm not sure what to say about this.
A client MAY warn a user of a TLS 1.2 connection is established, and
SHOULD warn the user of a client certifiate will be transmitted via
TLS 1.2.
It's "if" rather than "of", right?
Yes, fixed. Thanks.
-spc
[1] gemini://gemini.bortzmeyer.org/software/lupa/stats.gmi