Re: [TLS] (strict) decoding of legacy_record_version?
Brian Smith <brian@briansmith.org> Tue, 08 November 2016 03:01 UTC
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From: Brian Smith <brian@briansmith.org>
Date: Mon, 7 Nov 2016 17:01:18 -1000
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To: David Benjamin <davidben@chromium.org>
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Cc: Matt Caswell <matt@openssl.org>, "tls@ietf.org" <tls@ietf.org>
Subject: Re: [TLS] (strict) decoding of legacy_record_version?
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David Benjamin <davidben@chromium.org> wrote: > Once you've gotten as far as to switch to TLSCiphertext, I don't see a > reason not to enforce. Keying on versions is problematic (which is why we > avoided a transition to enforcement), but keying on whether the record is > encrypted seems fine. I think it just didn't occur to us to base it on > that. :-) > Since this field isn't included in the additional_data of the AEAD in TLS 1.3 any more, it isn't authenticated. That means an active MitM can use this to transport up to 2 bytes of information hop-to-hop if the receiver doesn't check it. That seems like a good reason to check it, and also to check TLSCiphertext.opaque_type is application_data. Assuming this is the reason, the reasoning should be explicitly called out because it is non-obvious. If that isn't a reason to do the check, then I don't think there's any reason to mandate that implementations do it. Cheers, Brian -- https://briansmith.org/
- [TLS] PR#625: Change alert requirements Eric Rescorla
- Re: [TLS] PR#625: Change alert requirements Sean Turner
- Re: [TLS] PR#625: Change alert requirements Watson Ladd
- Re: [TLS] PR#625: Change alert requirements Hubert Kario
- Re: [TLS] PR#625: Change alert requirements Eric Rescorla
- Re: [TLS] PR#625: Change alert requirements Hubert Kario
- Re: [TLS] PR#625: Change alert requirements Andrei Popov
- Re: [TLS] PR#625: Change alert requirements Eric Rescorla
- Re: [TLS] PR#625: Change alert requirements Martin Rex
- Re: [TLS] PR#625: Change alert requirements David Benjamin
- Re: [TLS] PR#625: Change alert requirements Timothy Jackson
- Re: [TLS] PR#625: Change alert requirements Ilari Liusvaara
- Re: [TLS] PR#625: Change alert requirements Salz, Rich
- Re: [TLS] PR#625: Change alert requirements Martin Rex
- Re: [TLS] PR#625: Change alert requirements Salz, Rich
- Re: [TLS] PR#625: Change alert requirements Salz, Rich
- Re: [TLS] PR#625: Change alert requirements Hubert Kario
- Re: [TLS] PR#625: Change alert requirements Hannes Tschofenig
- Re: [TLS] PR#625: Change alert requirements Benjamin Kaduk
- Re: [TLS] PR#625: Change alert requirements Martin Thomson
- Re: [TLS] PR#625: Change alert requirements Ilari Liusvaara
- Re: [TLS] PR#625: Change alert requirements Hubert Kario
- Re: [TLS] PR#625: Change alert requirements Sean Turner
- Re: [TLS] PR#625: Change alert requirements Eric Rescorla
- Re: [TLS] PR#625: Change alert requirements Eric Rescorla
- Re: [TLS] PR#625: Change alert requirements Eric Rescorla
- Re: [TLS] PR#625: Change alert requirements Hubert Kario
- Re: [TLS] PR#625: Change alert requirements Eric Rescorla
- [TLS] (strict) decoding of legacy_record_version? Benjamin Kaduk
- Re: [TLS] (strict) decoding of legacy_record_ve... David Benjamin
- Re: [TLS] (strict) decoding of legacy_record_ve... Eric Rescorla
- Re: [TLS] (strict) decoding of legacy_record_ve... Brian Smith
- Re: [TLS] (strict) decoding of legacy_record_ve... Martin Thomson
- Re: [TLS] (strict) decoding of legacy_record_ve... Brian Smith
- Re: [TLS] (strict) decoding of legacy_record_ve... Martin Thomson
- Re: [TLS] (strict) decoding of legacy_record_ve... Benjamin Kaduk
- [TLS] Treatment of (legacy_record_)version fiel... Andreas Walz
- Re: [TLS] Treatment of (legacy_record_)version ... Eric Rescorla
- Re: [TLS] Treatment of (legacy_record_)version ... Andreas Walz