oss-sec mailing list archives
Re: can we talk about secure time?
From: Hanno Böck <hanno () hboeck de>
Date: Mon, 22 Dec 2014 06:51:46 +0100
On Sun, 21 Dec 2014 12:31:07 +0100 Florian Weimer <fw () deneb enyo de> wrote:
Some folks want to run their servers within a few milliseconds of each other, and do not care so much about security or resiliency.
I perfectly understand that some people need more accuracy than tlsdate can give. However it's probably rare, right? I don't see any reason why average consumer hardware (Desktop, smartphone etc.) would have any problem with the 1-2 sec max inaccuracy of tlsdate.
Reconciling this with cryptography is certainly a challenge. On the other hand, this does not have to be the default.
I think it shouldn't be too hard to get both. You could do an asymmetric key exchange before you do any time transmission. Then the only thing you really need is a single authentication operation (HMAC or whatever). That shouldn't delay by any significant amount.
I think most desktop-based distributions could get away with something like tlsdate. In contrast, servers with long-running connections and I/O polling loops often do not react gracefully to jumps in time. (I once disconnected a few hundreds, if not thousands of users from an IRC server just by setting its time correctly.) Sure, you can avoid that by using the appropriate kernel clock for timeout handling, but I have the impression that the correct clock changes every couple of years.
tlsdate has tlsdated, I hope it acts intelligent and doesn't do time jumps. Haven't tested though. -- Hanno Böck http://hboeck.de/ mail/jabber: hanno () hboeck de GPG: BBB51E42
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Current thread:
- can we talk about secure time? Hanno Böck (Dec 20)
- Re: can we talk about secure time? Stuart Henderson (Dec 20)
- Re: can we talk about secure time? Daniel Kahn Gillmor (Dec 20)
- Re: can we talk about secure time? ncl () cock li (Dec 20)
- Re: can we talk about secure time? Daniel Micay (Dec 20)
- Re: can we talk about secure time? Florian Weimer (Dec 21)
- Re: can we talk about secure time? Daniel Micay (Dec 21)
- Re: can we talk about secure time? Dave Horsfall (Dec 21)
- leap seconds and security [was: Re: can we talk about secure time?] Daniel Kahn Gillmor (Dec 21)
- Re: can we talk about secure time? Florian Weimer (Dec 21)
- Re: can we talk about secure time? Hanno Böck (Dec 21)
- Re: can we talk about secure time? Kurt Seifried (Dec 21)
- Re: can we talk about secure time? Hanno Böck (Dec 21)
- Re: can we talk about secure time? Walter Parker (Dec 21)
- Re: can we talk about secure time? John Haxby (Dec 22)
- Re: can we talk about secure time? Dave Horsfall (Dec 22)
- Re: can we talk about secure time? Richard Johnson (Dec 25)
- Re: can we talk about secure time? Stuart Henderson (Dec 20)