[tor-dev] Proposal: Stop giving Exit flags when only unencrypted traffic can exit

Tue Jan 5 19:15:32 UTC 2016

> Other protocols (SSH, IMAP,
> POP3, SMTP) are indeed more popular but I feel that those less reflect
> the goals of the project, and they are certainly abused more.

I hear you that these are abused more.  But I personally think of Tor as a
mere mechanism than a mechanism+policy.  For example, should the command
"rm" refuse to remove a file that has the text in it that says "IMPORTANT!
DO NOT DELETE!"  Although obviously this is a well-intentioned feature,
presumably rm should not behave this way.  The rm command is a mechanism,
the policy for that mechanism judicious use is a wrapping around the
command itself.

One additional benefit of separating mechanism from policy is that it makes
policies more easily changeable.  Well-meaning people have disagreements on
policies, and policies invariably evolve.  Separating policies from the
core functionality is helpful to allow easier experimentation with
alternative policies.

Applying this here, I argue that the ports a relay makes available should
not impact whether they get the exit flag.  This is consistent with
treating Tor as a mechanism instead of applying top-down a policy for how
people are "supposed" to use it.

-V

On Wed, Jan 6, 2016 at 2:25 AM Tom van der Woerdt <info at tvdw.eu> wrote:

> Op 05/01/16 om 10:22 schreef Tim Wilson-Brown - teor:
> >
> >> On 5 Jan 2016, at 19:33, Tom van der Woerdt <info at tvdw.eu
> >> <mailto:info at tvdw.eu>> wrote:
> >> ...
> >> Op 05/01/16 om 02:15 schreef Tim Wilson-Brown - teor:
> >>>
> >>>> On 5 Jan 2016, at 11:29, Tom van der Woerdt <info at tvdw.eu
> >>>> <mailto:info at tvdw.eu>
> >>>> <mailto:info at tvdw.eu>> wrote:
> >>>> ...
> >>>> 2.1. Exit flagging
> >>>>
> >>>> By replacing the port 6667 (IRC) entry with a port 5222 (XMPP) entry,
> >>>> Exit
> >>>> flags can no longer be assigned to relays that exit only to
> unencrypted
> >>>> ports.
> >>>
> >>> One consequence of this proposal is that relays that only exit to 443
> >>> and 6667 will lose the Exit flag.
> >>> But these relays do exit to an encrypted port, so this somewhat
> >>> contradicts the goal of the proposal:
> >>> "Exit flags can no longer be assigned to relays that exit only to
> >>> unencrypted ports."
> >>
> >> ...
> >>
> >> (tlcr: any relay that currently holds an Exit flag and allows exiting to
> >> 443 and 6667, but not 80 or 5222.)
> >>
> >> tiggersWeltTor1 Bandwidth=2600
> >> smallegyptrela01 Bandwidth=22
> >>
> >> These two relays will be impacted, indeed.
> >
> > Point taken!
> >
> > How many Exits would lose the Exit flag intentionally based on this
> change?
> > (That is, how many have 80 & 6667, but not 443?)
>
> If we change 6667 to 5222, this changes (where 0->1 means it will become
> an exit and 1->0 means it will no longer be one) :
>
>   FruityOatyTorexit Bandwidth=17700 0->1
>   Alice Bandwidth=25 0->1
>   tiggersWeltTor1 Bandwidth=3100 1->0
>   onionnetGOT01 Bandwidth=387 0->1
>   icubdw2o2xipsdc Bandwidth=137 1->0
>   miepernl Bandwidth=1420 1->0
>   ReservoirPi2016 Bandwidth=114 0->1
>   TORWeazel Bandwidth=98 0->1
>   HelloWorld Bandwidth=820 1->0
>   smallegyptrela01 Bandwidth=22 1->0
>   AnonNodeFin69 Bandwidth=80 0->1
>   Serveur Bandwidth=703 0->1
>   Biverse Bandwidth=779 0->1
>   comaTor1 Bandwidth=148 0->1
>   Unnamed Bandwidth=138 1->0
>
> Gained bw: 20034
> Lost bw: 5637
>
> Tom
>
>
> (source of this data: https://paste.debian.net/360256/)
>
>
> >
> >>>
> >>> Why not make the rule: "at least one of 80/6667, and at least one of
> >>> 443/5222".
> >>
> >> Also sounds good to me. I opted for the smallest possible change
> >> (6667->5222) but what you're suggesting lgtm.
> >>
> >>>
> >>> I am also concerned about the choice of XMMP "because the XMPP protocol
> >>> is slowly gaining popularity within the
> >>> communities on the internet".
> >>> Shouldn't we focus on secure protocols that are widely used right now?
> >>>
> >>> Alternately, we could add other widely used SSL ports in addition to
> >>> XMMP, and perhaps increase the rule to "at least two SSL ports".
> >>
> >> Imho the challenge is in finding port number(s) that accurately reflect
> >> what Tor is for, while also having a sufficiently large user base for it
> >> to be relevant. XMPP probably has more users than IRC, and is a good
> >> match for what I think Tor would consider important (communication).
> >> Also note that we now have Tor Messenger. Other protocols (SSH, IMAP,
> >> POP3, SMTP) are indeed more popular but I feel that those less reflect
> >> the goals of the project, and they are certainly abused more.
> >
> > 80/443 get us anonymous web browsing, primarily through Tor Browser
> > 6667/6697 get us anonymous messaging via IRC
> > (I don't know if 6697 is common enough to be worth changing for.)
> > 5222 get us anonymous messaging via Tor Messenger
> >
> > I can't think of any others right now.
> >
> > Tim
> >
> > Tim Wilson-Brown (teor)
> >
> > teor2345 at gmail dot com
> > PGP 968F094B
> >
> > teor at blah dot im
> > OTR CAD08081 9755866D 89E2A06F E3558B7F B5A9D14F
> >
> >
> >
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> > https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-dev
> >
>
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