[tor-bugs] #28912 [- Select a component]: Stream hangs while downloading consensus via RELAY_BEGIN_DIR

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#28912: Stream hangs while downloading consensus via RELAY_BEGIN_DIR
--------------------+--------------------------------------
 Reporter:  plcp`   |          Owner:  (none)
     Type:  defect  |         Status:  new
 Priority:  Medium  |      Component:  - Select a component
  Version:          |       Severity:  Normal
 Keywords:          |  Actual Points:
Parent ID:          |         Points:
 Reviewer:          |        Sponsor:
--------------------+--------------------------------------
 After performing the following sequence of steps to download a consensus
 through a stream, Tor hangs after sending 58 (17 with deflate) cells:

 1. Open an TLS connection to a local OR.
 2. Negotiate a v5 link on the connection.
 3. Create a circuit via CREATE_FAST.
 4. Create a stream via RELAY_BEGIN_DIR.
 5. Send a request to download a consensus.

 I managed to reproduce the issue with the code attached. Here are an
 excerpt of the file:

 {{{
 '''Using identity, we get 58 RELAY_DATA cells before hanging, 17 with
 deflate.

     Affected:
         Tor version 0.3.4.0-alpha-dev (git-3463b4e0652bacca).

     Not affected:
         Tor version 0.3.3.5-rc-dev (git-3ee4c9b1fae9d535).
 '''

 compression = b'identity' # or b'deflate'

 '''Issue reproduced with the code below, originally bisected on [1].

         From tag:tor-0.3.4.1-alpha                      Affected?

         deb8970a29ef7427c3d42182d3bacc31ab602c03        yes
         2d7b5c6fe5dc46b7e7cd040e6723e25d12015985        yes
         3fa66f97996c179388fa91176b9a82fb9b5b31d8        no
         306563ac68250872791350bda1ba7a7acff5eb63        no
         3ee4c9b1fae9d53556b3e3be852f12e9abe51e14        no
         c32108ee0fea851ced14f71d842390992f762393        yes
         22845df2a7503ed73ed325c3a98916f289918caa        no
         c7d3de216c60c090fddb4926a739da038bb5d5fe        yes
         9ef4c05df8323850b5894782f435da15810d6189        no
         5e0fbd7006993a4e402f2eee49f6f86074923197        no
         c5899d5cf3a761f4049c1d6f05232731edcfeb57        no
         3463b4e0652bacca51fecd2c256e3e9d61ce920e        yes

     [1] Unpublished (yet) python client, no link here, sorry :(

     Usage:
         virtualenv venv
         source venv/bin/activate
         pip install -r stem cryptography
         tor PublishServerDescriptor 0 AssumeReachable 1 ExitRelay 0
 ProtocolWarnings 1 SafeLogging 0 LogTimeGranularity 1 PidFile '$(mktemp)'
 SOCKSPort 0 ContactInfo none at example.com DataDirectory '$(mktemp -d)'
 ORPort 9050 DirPort 9051 Log 'err stderr' &

         python reproduce.py
 '''
 }}}

 I provided the redacted logs for two different versions, one affected and
 one not.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/28912>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
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