[tor-bugs] #28921 [Core Tor/Stem]: tor-prompt command 'GETINFO desc/all-recent > /dev/null' fails

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#28921: tor-prompt command 'GETINFO desc/all-recent > /dev/null' fails
---------------------------+-----------------------------------
 Reporter:  wagon          |          Owner:  atagar
     Type:  defect         |         Status:  needs_information
 Priority:  Medium         |      Milestone:
Component:  Core Tor/Stem  |        Version:
 Severity:  Normal         |     Resolution:
 Keywords:  descriptor     |  Actual Points:
Parent ID:                 |         Points:
 Reviewer:                 |        Sponsor:
---------------------------+-----------------------------------

Comment (by wagon):

 > You misunderstand - my question was what python version are you using
 when you get this exact stacktrace. Do you get stacktraces with both
 python 2.7 and 3.4? If so then please provide the stacktrace you get for
 each since they should not be identical.
 OK, now it should be more clear. Old version, 1.6.0, which works fine, was
 installed using `pip3`:
 {{{
 $ pip3 show stem
 ---
 Name: stem
 Version: 1.6.0
 Location: /usr/local/lib/python3.4/dist-packages
 Requires:
 }}}
 Inside `tor-prompt` it reports itself as 3.4.2:
 {{{
 >>> import sys; print(sys.version)
 3.4.2 (default, Sep 25 2018, 22:02:39)
 [GCC 4.9.2]
 }}}
 A header of `tor-prompt` file is `#!/usr/bin/python3`.

 Now, let's consider new version installed from git. In `tor-prompt` it
 says:
 {{{
 >>> import sys; print(sys.version)
 2.7.9 (default, Sep 25 2018, 20:42:16)
 [GCC 4.9.2]
 }}}
 A header of `tor-prompt` executable is `#!/usr/bin/env python`.

 In my system both python2 and python3 are installed. Due to `python` in
 header git version fails. If I edit this file by replacing `python` by
 `python3`, the error disappears.

 I think you should stick to python3 version in your git code if user has
 `python3` installed. Just `python` should be used only as a fallback, when
 user doesn't have the third version. Thus, since everything works in
 `python3`, and `python2` will not be supported someday anyway, you could
 fix headers and mark this ticket as resolved.

 > I'm having difficulty seeing how version 1.7.0 could succeed in this
 respect
 It was 1.6.0. However, as I've just written, both version works with
 `python3`.

 > This is incorrect. Eavesdropping on a guard simply tells you that
 someone is using tor. Not where they're going. Deanonymization, say via a
 correlation attack, requires monitoring both your entry *and* exit
 traffic.
 I look at this from simple theoretical point of view. Anonymity is
 indistinguishability of somebody (particular user) on so-called "anonymity
 set" (all tor users). If nothing is known about you except of "your are
 tor user" you get the best anonymity achievable in Tor network.

 If you start logging to trac with a particular user name, you are no
 longer (ideally) anonymous, but pseudonymous. It means anybody can see
 what you are doing in Tor network, but nobody knows who you are.
 Pseudonymous users are less anonymous.

 Then, if somebody knows even more information about you or your network
 connection, your "anonymity set" reduces more. When nothing is known about
 you except your habit to use tor, you are one in 2 millions, so the
 anonymity set is big which makes it hard to geolocate you. If your guard
 is known, for powerful adversary your anonymity set is reduced to the
 number of tor users who selected particular guard node. It is about 1
 thousand users. As you see, by disclosing your guard you reduce your
 anonymity set 2000 times which makes targeted correlation attacks simpler.

 To get basic idea what is anonymity in network, look at definitions used
 for [[https://en.wikipedia.org/wiki/Mix_network|Chaum mixes]] and see how
 they [[https://www.freehaven.net/anonbib/|were developed further in Tor
 routing protocol]]. First  Tor papers with Roger and Nick should be easy
 for you to read.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/28921#comment:9>
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