[tor-bugs] #25616 [Core Tor/Tor]: Non-fatal assertion in hs_desc_encode_descriptor similar to #24972

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#25616: Non-fatal assertion in hs_desc_encode_descriptor similar to #24972
-------------------------------------------------+-------------------------
 Reporter:  alnsn                                |          Owner:  dgoulet
     Type:  defect                               |         Status:
                                                 |  accepted
 Priority:  High                                 |      Milestone:  Tor:
                                                 |  0.3.3.x-final
Component:  Core Tor/Tor                         |        Version:  Tor:
                                                 |  0.3.2.10
 Severity:  Normal                               |     Resolution:
 Keywords:  regression, tor-hs, 032-backport,    |  Actual Points:
  033-must 033-triage-20180326                   |
  033-included-20180326                          |
Parent ID:                                       |         Points:
 Reviewer:                                       |        Sponsor:
-------------------------------------------------+-------------------------

Comment (by asn):

 We discussed this with David. The most likely source of this bug is that
 we build the descriptor once (`build_service_descriptor()`) and then we
 keep it for many hours and we just encode the same desc over and over
 before publishing it (`upload_descriptor_to_hsdir()`. If the clock jumps
 after descriptor build, certs in our descriptor might expire before we
 encode it, and this BUG will get caused. Even tho the clock jumps, we
 don't expire the descriptor because `should_rotate_descriptor()` actually
 takes `ns` time as the authoritative source.

 A solution here would be to re-build the whole descriptor everytime before
 we encode it, so that we ensure that all certs are fresh before they enter
 the encode/decode function.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/25616#comment:12>
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