[tor-bugs] #21278 [Core Tor/Tor]: Avoid signed integer underflow when comparing versions (Fix TROVE-2017-001)

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#21278: Avoid signed integer underflow when comparing versions (Fix TROVE-2017-001)
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 Reporter:  nickm         |          Owner:  nickm
     Type:  defect        |         Status:  needs_revision
 Priority:  Medium        |      Milestone:  Tor: 0.3.0.x-final
Component:  Core Tor/Tor  |        Version:
 Severity:  Normal        |     Resolution:
 Keywords:  029-backport  |  Actual Points:
Parent ID:                |         Points:
 Reviewer:                |        Sponsor:
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Comment (by arma):

 Replying to [comment:3 nickm]:
 > My branch `bug21278_024_v2` tries to fix this

 I pushed a `bug21278_024_v3` branch that has an extra commit to better
 document the new function.

 That said, I think your commits 2c768c2c0 and 54e2e027 are only for dir
 auths, right? So there isn't any point in backporting them earlier than
 0.2.9?

 Speaking of which, for 4e720ad7 which looks like the main fix here, the
 changelog stanza says {{{This bug is harmless, except when Tor has been
 build with --enable-expensive-hardening, which would turn it into a
 crash.}}} Am I remembering correctly that only recent Tor branches have
 put expensive-hardening on by default? That is, the earlier fix for this
 TROVE (i.e. disabling ftrapv) only went into 0.2.9.x and 0.3.0.x? Why
 backport a fix for a harmless bug so far back? :)

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/21278#comment:7>
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