[tor-bugs] #28525 [Core Tor/Tor]: Make tor_addr_is_internal_() aware of RFC 6598 (Carrier Grade NAT/Large Scale NAT) IPv4 Ranges

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#28525: Make tor_addr_is_internal_() aware of RFC 6598 (Carrier Grade NAT/Large
Scale NAT) IPv4 Ranges
-------------------------------------------------+-------------------------
 Reporter:  neel                                 |          Owner:  neel
     Type:  defect                               |         Status:
                                                 |  needs_revision
 Priority:  Medium                               |      Milestone:  Tor:
                                                 |  0.4.1.x-final
Component:  Core Tor/Tor                         |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  ipv6, 040-deferred-20190220,         |  Actual Points:
  040-backport, 035-backport, 034-backport,      |
  029-backport, security-low                     |
Parent ID:                                       |         Points:
 Reviewer:  nickm, teor                          |        Sponsor:
-------------------------------------------------+-------------------------
Changes (by teor):

 * status:  needs_review => needs_revision
 * cc: teor (removed)
 * milestone:  Tor: unspecified => Tor: 0.4.1.x-final
 * keywords:  ipv6, 040-deferred-20190220 =>
     ipv6, 040-deferred-20190220, 040-backport, 035-backport, 034-backport,
     029-backport, security-low
 * reviewer:  nickm => nickm, teor
 * type:  enhancement => defect


Comment:

 It seems ok to me.

 It's a bit weird that we don't list 0.0.0.0 in the list of internal
 addresses. But no sensible OS will try to connect to it anyway, so that
 doesn't really matter. (And if we want to fix 0.0.0.0, we should do it in
 another ticket.)

 This patch mitigates some security issues created by RFC 6598 by:
 * blocking control ports on RFC 6598 addresses
 * warning when client ports and ExtORPorts are on RFC 6598 addresses
 (Despite our earlier comments, we don't currently block or warn on RFC
 6598 addresses.)

 So I'm marking it for possible backport.

 Here's what we should do before we merge:
 * update the changes file to describe these major, user-visible security
 changes
 * squash and cherry-pick to maint-0.2.9

 neel, are you ok making these changes?
 Just let us know if you can't, and someone will do it eventually.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/28525#comment:22>
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