[tor-bugs] #13280 [Tor]: Stop signed left shift overflows in ed25519

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#13280: Stop signed left shift overflows in ed25519
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     Reporter:  teor    |      Owner:
         Type:  defect  |     Status:  needs_review
     Priority:  major   |  Milestone:  Tor: 0.2.6.x-final
    Component:  Tor     |    Version:  Tor: unspecified
   Resolution:          |   Keywords:  tor-router ed25519
Actual Points:          |  Parent ID:
       Points:          |
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Comment (by nickm):

 This seems like a good idea to do.  One question we'll need to think
 about:

 Since this is a pretty mechanical transformation, can we verify its
 correctness mechanically?  I'm thinking about diffing the assembly output
 of the two cases, or writing a script (with coccinelle? with perl?) to
 replicate the transformation, or something like that.  Otherwise,
 verifying all 200 changed lines by eye seems like the kind of thing I
 might make a mistake with.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/13280#comment:5>
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