No Control Socket when DisableNetwork and User options are set
To successfully reproduce this, we need:
- set DisableNetwork to 1
- use User option as part of the Tor configuration
- run sudo Tor from a different user in a different group
Here are the specific steps to reproduce it. I tested it on Debian Stretch but it should be distribution independent:
user at host:~$ cat /home/user/my.torrc DataDirectory /tmp/tor ControlSocket /tmp/tor/control.sock ControlSocketsGroupWritable 1 CookieAuthentication 1 CookieAuthFileGroupReadable 1 CookieAuthFile /tmp/tor/control.authcookie SocksPort unix:/tmp/tor/socks.sock
user at host:~$ sudo /usr/bin/install -Z
-m 02755 -o debian-tor
-g debian-tor -d /tmp/tor
user at host:~$ ls -ld /tmp/tor/; ls -l /tmp/tor/ drwxr-s--- 2 debian-tor debian-tor 40 Feb 3 18:19 /tmp/tor/ total 0
user at host:~$ sudo /usr/bin/tor
-f /home/user/my.torrc
--User debian-tor
--DisableNetwork 1
There should be control.sock, but not:
user at host:~$ ls -ld /tmp/tor/; sudo ls -l /tmp/tor/ drwx--S--- 2 debian-tor debian-tor 100 Feb 3 20:00 /tmp/tor/ total 8 -rw-r----- 1 debian-tor debian-tor 32 Feb 3 20:00 control.authcookie -rw------- 1 debian-tor debian-tor 0 Feb 3 20:00 lock -rw------- 1 debian-tor debian-tor 215 Feb 3 20:00 state
To let Tor really open the control.sock, we need to reload Tor (yes, even though we just start it):
user at host:~$ ps -A | grep tor 863 ? 00:00:00 xenstore-watch 927 ? 00:00:04 tor-controlport 11851 pts/0 00:00:00 tor
user at host:~$ sudo /bin/kill -HUP 11851
user at host:~$ ls -ld /tmp/tor/; sudo ls -l /tmp/tor/ drwx--S--- 2 debian-tor debian-tor 120 Feb 3 20:01 /tmp/tor/ total 8 -rw-r----- 1 debian-tor debian-tor 32 Feb 3 20:01 control.authcookie srw-rw---- 1 debian-tor debian-tor 0 Feb 3 20:01 control.sock -rw------- 1 debian-tor debian-tor 0 Feb 3 20:01 lock -rw------- 1 debian-tor debian-tor 215 Feb 3 20:01 state
I guess the reason Yawning was not able to reproduce it is because User option was not set:
user at host:~$ sudo -u debian-tor
/usr/bin/tor -f /home/user/my.torrc
--DisableNetwork 1
[notice] Opening Control listener on /tmp/tor/control.sock
I was thinking Tor fixing /tmp/tor/ to 2700 may be the reason, but then I cannot explain why this will work with /tmp/tor/ set to 2700:
user at host:~$ sudo /usr/bin/tor
-f /home/user/my.torrc
--User debian-tor
--DisableNetwork 0
[notice] Opening Control listener on /tmp/tor/control.sock