On Tue, Jul 11, 2017 at 1:39 PM, Benjamin Kaduk <bka...@akamai.com> wrote: > > > Another question I also relates to 0-RTT, specifically with the freshness > checks and the case where the computed expected_arrival_time is in outside > "the window" by virtue of being in the future. (See the Note: at the end of > section 8.2.) (The case where the expected_arrival_time is in the past can > clearly be treated as "this is a stale request" and the current text about > aborting with "illegal_parameter" or rejecting 0-RTT but accepting the PSK > is acceptable, even if it doesn't give guidance as to what might cause > someone to pick one behavior or the other.) I am wondering whether we > should consider this to be a potential attack and abort the connection. I > concede that there are likely to be cases where this > situation occurs incidentally, for clients with extremely fast-running > clocks, and potential timezone/suspend-resume weirdness. But there is also > the potential for a client that deliberately lies about its ticket age and > intends to replay the wire messages when the age becomes in window, or an > attacker that records the messages and knows that the client's clock is too > fast, or other cases. (A client that deliberately does this could of > course just send the same application data later as well.) If the time is > only a few seconds out of the window, then delaying a response until it is > in the window and only then entering it into the single-use cache might be > reasonable, but if the time is very far in the future, do we really want to > try to succeed in that case? >
If the time is very far in the future, the text is supposed to tell you to fall back to 1-RTT... It looks like we no longer do anything to obsolete/reserve/similar the > HashAlgorithm and SignatureAlgorithm registries; was that just an editorial > mixup or an intended change? > https://tlswg.github.io/draft-ietf-tls-iana-registry-updates/#orphaned-registries We removed the API guidance for separate APIs for read/writing early data > versus regular data, which I believe had consensus. But I thought we were > going to say something carefully worded about having an API to determine > whether the handshake has completed (or client Finished has been validated, > or ...), and it looks like this is buried at the end of E.5(.0), with the > string "API" not appearing. It might be useful to make this a little more > prominent/discoverable, whether by subsection heading or otherwise. > Suggestions welcome for where this would be better.... -Ekr > > I also found some issues that I believe to be purely editorial, for which > I will submit a pull request. > > I will probably try to make another full review pass over the entire > document (mostly looking for editorial things), but I have until the end of > IETF LC for that, right? ;) > > -Ben > > _______________________________________________ > TLS mailing list > TLS@ietf.org > https://www.ietf.org/mailman/listinfo/tls > >
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