[tor-bugs] #13471 [Tor]: router daemon crashes with openssl built no_ssl3

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#13471: router daemon crashes with openssl built no_ssl3
-------------------------+-------------------------------------------------
     Reporter:           |      Owner:
  starlight              |     Status:  new
         Type:  defect   |  Milestone:  Tor: 0.2.6.x-final
     Priority:  blocker  |    Version:  Tor: 0.2.4.24
    Component:  Tor      |   Keywords:  tor-relay ssl3 poodle 025-backport
   Resolution:           |  024-backport 023-backport
Actual Points:           |  Parent ID:
       Points:           |
-------------------------+-------------------------------------------------

Comment (by starlight):

 I'll have to take a look at --enable-expensive-hardening.

 I see in

 gcc-4.9.1/libsanitizer/include/sanitizer/asan_interface.h

 {{{
   // This function may be optionally provided by user and should return
   // a string containing ASan runtime options. See asan_flags.h for
 details.
   const char* __asan_default_options();
 }}}

 which seems like it will do the job.  Be aware that
 many references are made in web-postings regarding
 ASAN to usage similar to

 {{{
 #if defined(__has_feature)
 #if __has_feature(address_sanitizer)
   __sanitizer_sandbox_on_notify(NULL);
 #endif
 #endif
 }}}

 which I call to allow ASAN to work with
 `/chroot_tor/proc` unmounted after
 startup, but the conditional compile is
 specific to CLANG and does not work for
 GCC.  You should create your own -DASANFLAG
 conditional compilation flag.  I only just
 figured this out and the above code was
 not working at all though I was
 laboring under the misconception
 that it was.

 Also be sure to either direct stdout/stderr
 to a file (as in my patch above) or configure
 the "log_path" ASAN option or ASAN will not
 work.  I favor standard I/O since sometimes
 glibc will write a message that may be
 of value.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/13471#comment:19>
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