[tor-bugs] #26870 [Core Tor/Tor]: Spec: clarify inconsistency for [V]PADDING/DROP cell content vs. padding bytes

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#26870: Spec: clarify inconsistency for [V]PADDING/DROP cell content vs. padding
bytes
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     Reporter:  dmr           |      Owner:  (none)
         Type:  defect        |     Status:  new
     Priority:  Medium        |  Milestone:
    Component:  Core Tor/Tor  |    Version:
     Severity:  Normal        |   Keywords:  tor-spec
Actual Points:                |  Parent ID:
       Points:                |   Reviewer:
      Sponsor:                |
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 This ticket is split off from #26228.

 Here's the relevant description from that ticket:
 Replying to [ticket:26228 dmr]:
 > [...]
 > ==== Unclear areas
 > Here are the points that need clarification / specification:
 > * [...]
 > * spec is a bit inconsistent with `PADDING` cells ^^[1^^]^^[2^^]
 > [...]
 >
 > ==== Inconsistency: `PADDING` cell payload
 > (see bullet above)
 >
 > These references highlight the inconsistency:
 >
 > ^^[1^^] `PADDING: Payload is unused.` per
 [[https://gitweb.torproject.org/torspec.git/tree/tor-
 spec.txt?id=f6e93d9751002d970614662c8173ff2fa5b7c193#n469|sec 3 "Cell
 Packet format"]].
 >   implies 0 bytes of payload, so the rest should be padded per that
 section
 > ^^[2^^] `The contents of a PADDING, VPADDING, or DROP cell SHOULD be
 chosen randomly, and MUST be ignored.` per
 [[https://gitweb.torproject.org/torspec.git/tree/tor-
 spec.txt?id=f6e93d9751002d970614662c8173ff2fa5b7c193#n1723|sec 7.2 "Link
 padding"]].
 >   implies the payload of a `PADDING` cell actually is the rest of the
 size of the cell, and that it SHOULD be chosen randomly
 >
 > The `PADDING` cells were mentioned in IRC but not discussed.
 > I think a simple change to make the spec consistent between the two
 sections would be this:
 > {{{
 > PADDING: Payload contains random data. (See Sec 7.2)
 > }}}
 >
 > However, given the other points here, is that correct?

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/26870>
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