Feature #5462

Persistence preset - Tor state

Added by Tails over 1 year ago. Updated 7 months ago.

Status:ConfirmedStart date:
Priority:NormalDue date:
Assignee:-% Done:

0%

Category:Persistence
Target version:Tails_3.0
QA Check: Blueprint:
Feature Branch: Easy:No
Type of work:Code Affected tool:

Description

Big picture

There are a few good reasons for making Tor's data dir persistent:

  1. Faster and less wasteful (in terms of bandwidth) bootstrap.
  2. Stronger resistance to certain attacks against anonymity via persistent Entry Guards.
  3. Using Entry Guards makes it harder to detect that you're using Tails.

Making /var/lib/tor persistent is enough for this. We should probably make a preset for it. Should it be enabled by default?

Issues

Persistent entry guards vs. mobile users

using persistent Entry Guards may be problem for mobile users (https://lists.torproject.org/pipermail/tor-talk/2012-October/025975.html).

Potential solutions:

Custom scripts relying on non-persistence

Some of our scripts depend on that certain files in /var/lib/tor are not persistent, which has to be resolved before adding the preset:

  • Our time syncing script uses the existence of cached-descriptors as a test for wheter Tor is working, and a similar assumption is made for the *-consensus files.
  • The Unsafe Browser uses cached-descriptors in the same way as the time syncing script.

At least "cached-descriptors existence checking" can be replaced with checking "GETINFO status/circuit-established" via the ControlPort. For tordate's *-consensus magic "GETINFO status/enough-dir-info" seems interesting, but isn't a replacement.

Shell function which is useful for the above:

tor_control_getinfo() {
  COOKIE=/var/run/tor/control.authcookie
  HEXCOOKIE=$(xxd -c 32 -g 0 $COOKIE | cut -d' ' -f2)
  echo -e "AUTHENTICATE $HEXCOOKIE\nGETINFO ${1}\nQUIT" | \
  nc 127.0.0.1 9051 | grep "^250-${1}=" | sed "s@^250-${1}=@@" 
}

Related issues

Related to Tails - Feature #5461: Persistence preset - Tor configuration Confirmed
Related to Tails - Feature #8825: Provide default bridges Confirmed 01/30/2015

History

#1 Updated by intrigeri over 1 year ago

  • Category set to Persistence
  • Easy set to No

#2 Updated by Anonymous about 1 year ago

(removed spam)

#3 Updated by Anonymous about 1 year ago

(removed spam)

#4 Updated by intrigeri about 1 year ago

  • Description updated (diff)

#5 Updated by Anonymous about 1 year ago

(removed spam)

#6 Updated by Anonymous about 1 year ago

(removed spam)

#7 Updated by Anonymous about 1 year ago

(removed spam)

#8 Updated by BitingBird 9 months ago

  • Subject changed from persistence preset - tor to Persistence preset - tor

#9 Updated by intrigeri 8 months ago

  • Subject changed from Persistence preset - tor to Persistence preset - Tor state

#10 Updated by intrigeri 7 months ago

  • Description updated (diff)

#11 Updated by sajolida about 1 month ago

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