Re: [TLS] 4366bis TLSext SNI -- case-sensitivity, permitted chars
Joe Salowey <jsalowey@cisco.com> Wed, 08 December 2010 16:03 UTC
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From: Joe Salowey <jsalowey@cisco.com>
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Date: Wed, 08 Dec 2010 08:05:40 -0800
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To: mrex@sap.com
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Cc: Geoffrey Keating <geoffk@geoffk.org>, tls@ietf.org
Subject: Re: [TLS] 4366bis TLSext SNI -- case-sensitivity, permitted chars
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This looks like an oversight in the new text. Just to clarify the suggestion is to add the following as a new paragraph after the paragraph ending "... use of A-labels defined in [RFC5890]." " DNS hostnames are case-insensitive. The algorithm to compare hostnames is described in [RFC5890] Section 2.3.2.4." Thanks, Joe On Nov 18, 2010, at 12:37 PM, Martin Rex wrote:" > Geoffrey Keating wrote: >> >> Martin Rex <mrex@sap.com> writes: >> >>> Looking at the OpenSSL diffs for CVE-2010-3864 and crosschecking with >>> rfc4366 and rfc4366bis I noticed that some text was removed or lost >>> from the description of the Server Name Indication extension >>> for rfc4366->rfc4366bis. >>> >>> >>> The IMHO most important part that was lost is: >>> >>> "MUST compare ... case-insensitively." >>> >>> and OpenSSL appears to perform a case-sensitive match (strncmp) only. >> ... >>> New text is: >>> https://tools.ietf.org/html/draft-ietf-tls-rfc4366-bis-12#page-8 >>> >>> "HostName" contains the fully qualified DNS hostname of the server, >>> as understood by the client. The hostname is represented as a byte >>> string using ASCII encoding without a trailing dot. This allows the >>> support of internationalized domain names through the use of A-labels >>> defined in [RFC5890]. >>> >>> Literal IPv4 and IPv6 addresses are not permitted in "HostName". >> >> Perhaps we could insert this between the two paragraphs quoted: >> >> The DNS hostname is to be compared in a case-insensitive manner but >> case should be preserved, as described in [RFC1035]. >> >> (The RFC 1035 reference is so that we don't have to explain what >> 'case-insensitive' means.) > > Considering the new Reference to [RFC5890], pointing to Section 2.3.2.4 > of that document might be more appropriate. > > https://tools.ietf.org/html/rfc5890#section-2.3.2.4 > > So something like > > DNS hostnames are case-insensitive. The algorithm to compare > hostnames is described in [RFC5890] Section 2.3.2.4. > > might be more consistent. > > -Martin > _______________________________________________ > TLS mailing list > TLS@ietf.org > https://www.ietf.org/mailman/listinfo/tls
- [TLS] 4366bis TLSext SNI -- case-sensitivity, per… Martin Rex
- Re: [TLS] 4366bis TLSext SNI -- case-sensitivity,… Martin Rex
- Re: [TLS] 4366bis TLSext SNI -- case-sensitivity,… Geoffrey Keating
- Re: [TLS] 4366bis TLSext SNI -- case-sensitivity,… Martin Rex
- Re: [TLS] 4366bis TLSext SNI -- case-sensitivity,… Martin Rex
- Re: [TLS] 4366bis TLSext SNI -- case-sensitivity,… Joe Salowey
- Re: [TLS] 4366bis TLSext SNI -- case-sensitivity,… Martin Rex