[tor-bugs] #24733 [Core Tor/Tor]: Loading ifc.ifc_buf using the new tor_free() causes undefined behaviour on x86_64 macOS

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#24733: Loading ifc.ifc_buf using the new tor_free() causes undefined behaviour on
x86_64 macOS
-------------------------------------------------+-------------------------
 Reporter:  teor                                 |          Owner:  teor
     Type:  defect                               |         Status:
                                                 |  merge_ready
 Priority:  Medium                               |      Milestone:  Tor:
                                                 |  0.3.3.x-final
Component:  Core Tor/Tor                         |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  address-sanitizer, unexpected-       |  Actual Points:  0.1
  consequences                                   |
Parent ID:                                       |         Points:  0.1
 Reviewer:                                       |        Sponsor:
                                                 |  Sponsor8-can
-------------------------------------------------+-------------------------

Comment (by teor):

 The newly introduced load to a local pointer variable from an address
 that's (N*8 + 4).
 I don't think the type of the pointer matters.
 Strangely, the comparison of that address to NULL, and the store of NULL
 to that address doesn't trigger the same warning in AddressSanitizer (or
 they are optimised out by the compiler!)

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/24733#comment:3>
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