Hi Adam,
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
