[tor-bugs] #16069 [Tor]: ipv4 + ipv6 exit : v6 policy is displayed twice, v4 isn't displayed

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#16069: ipv4 + ipv6 exit : v6 policy is displayed twice, v4 isn't displayed
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     Reporter:  toralf    |      Owner:
         Type:  defect    |     Status:  needs_revision
     Priority:  critical  |  Milestone:  Tor: 0.2.7.x-final
    Component:  Tor       |    Version:  Tor: 0.2.7
   Resolution:            |   Keywords:  026-backport, ipv6, PostFreeze027
Actual Points:            |  Parent ID:
       Points:            |
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Comment (by teor):

 Replying to [comment:20 nickm]:
 > Design notes:
 >
 > I think that changing the meaning of accept/reject * to mean IPv4 only
 is too risky for 0.2.7.  I think we could safely have those continue to
 mean what they mean today.

 I agree. I just couldn't work out how to fix this issue, and maintain the
 old behaviour. I like your solution.

 > I think it's fine to do a NOTICE when * means "IPv4 and IPv6".
 >
 > I think accept6 * should mean "accept *6".

 So the full specification would be:
 * accept/reject * means IPv4 and IPv6 with NOTICE
 * accept/reject IPv4 or *4 means IPv4
 * accept/reject IPv6 or *6 means IPv6

 * accept6/reject6 * means IPv6 only (changed behaviour, but no-one
 expected it to mean IPv4)
 * accept6/reject6 IPv4 or *4 means ignore with WARN? (changed behaviour,
 but no-one expected it to mean IPv4)
 * accept6/reject6 IPv6 or *6 means IPv6 (existing behaviour)

 > Code notes:
 >
 > It seems like the TAPMP_IPV[46]_ONLY options won't actually stop any
 addresses that *don't* begin with a star.  That seems wrong. I would
 expect TAPMP_IPV4_ONLY to reject [FE80::]/16:80, for example.

 The TAPMP_IPV[46]_ONLY code only controls what * gets expanded into.

 The code in `router_parse_addr_policy` rejects address family mismatches,
 regardless of whether they came from a * or a specific address, and
 regardless of whether they came from a torrc or a descriptor.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/16069#comment:22>
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