[tor-bugs] #31009 [Core Tor/Tor]: Tor lets transports advertise private IP addresses in descriptor

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#31009: Tor lets transports advertise private IP addresses in descriptor
--------------------------+------------------------
 Reporter:  phw           |          Owner:  (none)
     Type:  defect        |         Status:  new
 Priority:  Medium        |      Milestone:
Component:  Core Tor/Tor  |        Version:
 Severity:  Normal        |     Resolution:
 Keywords:                |  Actual Points:
Parent ID:                |         Points:  0.5
 Reviewer:                |        Sponsor:
--------------------------+------------------------

Comment (by arma):

 Replying to [comment:3 arma]:
 > when Tor is building its extrainfo descriptor, it should notice that
 it's about to advertise an internal address

 Here is my one-liner that implements this idea:

 {{{
 diff --git a/src/feature/client/transports.c
 b/src/feature/client/transports.c
 index 97bfc8a..bd7d955 100644
 --- a/src/feature/client/transports.c
 +++ b/src/feature/client/transports.c
 @@ -1641,7 +1641,7 @@ pt_get_extra_info_descriptor_string(void)
         * returned address. */
        const char *addrport = NULL;
        uint32_t external_ip_address = 0;
 -      if (tor_addr_is_null(&t->addr) &&
 +      if (tor_addr_is_internal(&t->addr, 0) &&
            router_pick_published_address(get_options(),
                                          &external_ip_address, 0) >= 0) {
          tor_addr_t addr;
 }}}

 It turns out the code already did the idea, but only in the case where it
 was about to advertise 0.0.0.0. So now it would do the same thing for a
 wider variety of internal addresses.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/31009#comment:4>
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