[tor-bugs] #24423 [Core Tor/Tor]: Fix STACK warnings in Tor

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#24423: Fix STACK warnings in Tor
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 Reporter:  nickm            |          Owner:  nickm
     Type:  defect           |         Status:  needs_review
 Priority:  Medium           |      Milestone:  Tor: 0.3.3.x-final
Component:  Core Tor/Tor     |        Version:
 Severity:  Normal           |     Resolution:
 Keywords:  review-group-27  |  Actual Points:
Parent ID:                   |         Points:
 Reviewer:  catalyst         |        Sponsor:
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Comment (by catalyst):

 Replying to [comment:22 gk]:
 > Replying to [comment:21 nickm]:
 > > I've tried the first approach you suggested, and didn't get
 signed/unsigned warnings, so lt's try it out.
 > >
 > > gk, does my `stack_again_032` branch fix the warning for you?
 >
 > Looks good now. Just the warning in `test` is still there (see comment:4
 and the respective attachment).
 That looks like another instance of `tor_malloc_zero()` (called from
 `new_fake_channel()`) always returning non-`NULL` (assuming the line
 numbers on maint-0.3.2 are still correct), so this conditional in
 `test_channel_flushmux()` is always true:
 {{{
     762   if (ch)
     763     circuitmux_free(ch->cmux);
 }}}
 Even better, there's also
 {{{
     718   ch = new_fake_channel();
     719   tt_assert(ch);
 }}}
 so that's another reason why it can't be `NULL`, along with other
 unconditional dereferences.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/24423#comment:23>
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