[tor-bugs] #8031 [Tor]: Assertion fast_memeq(md->body, "onion-key", 9) failed;

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#8031: Assertion fast_memeq(md->body, "onion-key", 9) failed;
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 Reporter:  cypherpunks                |          Owner:                    
     Type:  defect                     |         Status:  new               
 Priority:  normal                     |      Milestone:  Tor: 0.2.4.x-final
Component:  Tor                        |        Version:  Tor: 0.2.4.6-alpha
 Keywords:  tor-relay assertion crash  |         Parent:                    
   Points:                             |   Actualpoints:                    
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Comment(by cypherpunks):

 You can reproduce crash for second way. First you need to trigger
 rebuilding the microdescriptor cache, the simple way is to swap cached-
 microdescs and cached-microdescs.new files so size of journal was bigger
 than cache for sure. Second you need to change file attributes on a file
 system to attribute file as immutable: chattr +i cached-microdescs (it
 probably need a root privs). Start Tor, see crash:

 {{{
 [Warning] Error replacing "./cached-microdescs": Operation not permitted
 [Error] microdesc_cache_rebuild(): Bug: After rebuilding microdesc cache,
 offsets seem wrong.  At offset xxx, I expected to find a microdescriptor
 starting  with "onion-key".  Instead I got "xxxxxxxxxxxxxxxxx".
 [Error] microdesc_cache_rebuild(): Bug: microdesc.c:491:
 microdesc_cache_rebuild: Assertion fast_memeq(md->body, "onion-key", 9)
 failed; aborting.
 }}}

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/8031#comment:13>
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