[tor-bugs] #30920 [Core Tor/Tor]: Detect uint64 overflow in config_parse_units()

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#30920: Detect uint64 overflow in config_parse_units()
---------------------------+------------------------------------
 Reporter:  nickm          |          Owner:  (none)
     Type:  defect         |         Status:  needs_revision
 Priority:  Low            |      Milestone:  Tor: 0.4.3.x-final
Component:  Core Tor/Tor   |        Version:
 Severity:  Minor          |     Resolution:
 Keywords:  easy overflow  |  Actual Points:
Parent ID:                 |         Points:
 Reviewer:  teor           |        Sponsor:
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Comment (by guigom):

 I've updated the PR.

 Replying to [comment:16 teor]:
 > Let's check that the value is less than INT64_MAX?
 > And let's check the result of the float multiplication, *before* we cast
 it to a uint64_t.
 > (We want to use a value that's significantly lower than UINT64_MAX, so
 that floating point calculations can't change the result.)

 Not sure if I got it right, waiting for an OK because I ended up writing
 the same block for the float as the uint case.

 INT64_MAX use_float before casting check:
 [https://github.com/torproject/tor/pull/1338/commits/7439c8ac421a3f4dba6c3d469bc6bc7e2ca86888
 #diff-3ae70660df167ed2300a9455223be6a9R146]

 Sorry this is taking this much time. It's been hard finding some free time
 lately, sorry for any inconvenience.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/30920#comment:18>
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