Trying again... > Hi Adam,
In CoRE we might need to allocate a new SNI NameType for non-DNS host names [1]. Removing SNI extensibility would make it unfeasible. Cheers, t [1] https://tools.ietf.org/html/draft-fossati-core-certmode-rd-names-00#section -3.3 >On 03/03/2016 18:49, "TLS on behalf of Adam Langley" <tls-boun...@ietf.org >on behalf of a...@imperialviolet.org> wrote: >>The Server Name Indication (SNI) extension in TLS has a provision to >>provide names other than host names[1]. None have even been defined to >>my knowledge, but it's there. >> >>OpenSSL (and possibly others) have had a long-standing bug[2] (fixed >>in master) that means that different types of names will cause an >>error. To be clear: I live in a glass house and am not throwing >>stones; these things happen. However, it means that a huge fraction of >>the TLS deployment will not be able to accept a different name type >>should one ever be defined. (This issue might have been caused by the >>fact that the original[3] spec didn't define the extension in such a >>way that unknown name types could be skipped over.) >> >>Therefore we (i.e. BoringSSL, and thus Google) are proposing to give >>up on this and implement our parser such that the SNI extension is >>only allowed to contain a single host name value. (This is compatible >>with all known clients.) We're assuming that since this is already the >>de-facto reality that there will be little objection. I'm sending this >>mostly to record the fact so that, if someone tries to define a new >>name type in the future, they won't waste their time. >> >>If the community wishes to indicate a different type of name in the >>future, a new extension can be defined. This is already effectively >>the case because we wouldn't fight this level of incompatibility when >>there's any other option. >> >>(I think the lesson here is that protocols should have a single joint, >>and that it should be kept well oiled. For TLS, that means that >>extensions should have minimal extensionality in themselves and that >>we should generally rely on the main extensions mechanism for these >>sorts of things.) >> >>[1] https://tools.ietf.org/html/rfc6066#section-3 >>[2] >>https://github.com/openssl/openssl/blob/OpenSSL_1_0_1-stable/ssl/t1_lib.c >># >>L1066 >> note that the data pointer is not updated. >>[3] https://tools.ietf.org/html/rfc4366#section-3.1 >> >> >>Cheers >> >>AGL >> >>-- >>Adam Langley a...@imperialviolet.org https://www.imperialviolet.org >> >>_______________________________________________ >>TLS mailing list >>TLS@ietf.org >>https://www.ietf.org/mailman/listinfo/tls > > _______________________________________________ TLS mailing list TLS@ietf.org https://www.ietf.org/mailman/listinfo/tls
