[tor-bugs] #16161 [Tor]: Tor dies on reload when swichting to 'DisableNetwork 0' when using 'DnsPort 127.0.0.1:53'

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#16161: Tor dies on reload when swichting to 'DisableNetwork 0' when using 'DnsPort
127.0.0.1:53'
--------------------+-------------------------------
 Reporter:  proper  |          Owner:
     Type:  defect  |         Status:  new
 Priority:  normal  |      Milestone:
Component:  Tor     |        Version:  Tor: 0.2.5.12
 Keywords:          |  Actual Points:
Parent ID:          |         Points:
--------------------+-------------------------------
 Using Tor on Debian `jessie`. Version:

 {{{
 dpkg-query --show --showformat='${Version}' "tor"
 0.2.5.12-1
 }}}

 For reproduction of this issue, you could run the following script as
 root.

 {{{
 #!/bin/bash

 set -x

 echo '
 DnsPort 127.0.0.1:53
 DisableNetwork 1
 ' > /etc/tor/torrc

 service tor restart

 sleep 2

 echo '
 DnsPort 127.0.0.1:53
 DisableNetwork 0
 ' > /etc/tor/torrc

 service tor reload
 }}}

 Log output:

 {{{
 May 22 22:06:59.000 [notice] Tor 0.2.5.12 (git-3731dd5c3071dcba) opening
 log file.
 May 22 22:06:59.000 [notice] Parsing GEOIP IPv4 file /usr/share/tor/geoip.
 May 22 22:06:59.000 [notice] Parsing GEOIP IPv6 file
 /usr/share/tor/geoip6.
 May 22 22:06:59.000 [notice] Bootstrapped 0%: Starting
 May 22 22:06:59.000 [notice] Delaying directory fetches: DisableNetwork is
 set.
 May 22 22:07:01.000 [notice] Received reload signal (hup). Reloading
 config and resetting internal state.
 May 22 22:07:01.000 [notice] Read configuration file "/usr/share/tor/tor-
 service-defaults-torrc".
 May 22 22:07:01.000 [notice] Read configuration file "/etc/tor/torrc".
 May 22 22:07:01.000 [notice] Opening Socks listener on 127.0.0.1:9050
 May 22 22:07:01.000 [notice] Opening DNS listener on 127.0.0.1:53
 May 22 22:07:01.000 [warn] Could not bind to 127.0.0.1:53: Permission
 denied
 May 22 22:07:01.000 [notice] Closing partially-constructed Socks listener
 on 127.0.0.1:9050
 May 22 22:07:01.000 [warn] Failed to parse/validate config: Failed to bind
 one of the listener ports.
 May 22 22:07:01.000 [err] Reading config failed--see warnings above. For
 usage, try -h.
 May 22 22:07:01.000 [warn] Restart failed (config error?). Exiting.
 }}}

 If `DnsPort 127.0.0.1:53` was out commented, this issue would not occur.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/16161>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
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