Re: [TLS] PR#625: Change alert requirements
Ilari Liusvaara <ilariliusvaara@welho.com> Sat, 10 September 2016 14:53 UTC
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Date: Sat, 10 Sep 2016 17:53:21 +0300
From: Ilari Liusvaara <ilariliusvaara@welho.com>
To: Martin Thomson <martin.thomson@gmail.com>
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Subject: Re: [TLS] PR#625: Change alert requirements
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On Sat, Sep 10, 2016 at 08:43:33PM +1000, Martin Thomson wrote: > > I wouldn't say that this is a great argument, but it's one that could > be made. Generally, I've given up on TLS error codes being useful, or > even making them useful; we've been stung in the past by being overly > specific about what went wrong. Well, regarding usefulness of TLS error codes, the error codes don't even come close to useful-for-debugging. This isn't because of information leaking (which AFAICT can only happen in very few places), but because error codes just are not expressive enough. Also, if you have a place where you worry about alerts leaking information to attacker, watch out, you might very well also have a timing attack. The places of TLS 1.3 that I can quickly name that are sensitive, and so one should take care to only send one kind of alert for each: - Deprotect failures (bad_record_mac) - MAC (finished) failures (decrypt_error) - key agreement failure (???, my code uses illegal_parameter[1]) - signature failures (internal_error) Also, note that with some bad cryptographic algorithms, one can't even let the other side know operation failed. So even just resetting the connection leaks too much information. [1] Logic being: It is likely provoked by peer sending invalid share -> invalid field value -> illegal_parameter.
- [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 Eric Rescorla
- Re: [TLS] PR#625: Change alert requirements Hubert Kario
- 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_vers… David Benjamin
- Re: [TLS] (strict) decoding of legacy_record_vers… Eric Rescorla
- Re: [TLS] (strict) decoding of legacy_record_vers… Brian Smith
- Re: [TLS] (strict) decoding of legacy_record_vers… Martin Thomson
- Re: [TLS] (strict) decoding of legacy_record_vers… Brian Smith
- Re: [TLS] (strict) decoding of legacy_record_vers… Martin Thomson
- Re: [TLS] (strict) decoding of legacy_record_vers… Benjamin Kaduk
- [TLS] Treatment of (legacy_record_)version field … Andreas Walz
- Re: [TLS] Treatment of (legacy_record_)version fi… Eric Rescorla
- Re: [TLS] Treatment of (legacy_record_)version fi… Andreas Walz