[tor-bugs] #20007 [Core Tor/Tor]: Sandbox causing crash when setting HidServAuth when there is a hidden service running

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#20007: Sandbox causing crash when setting HidServAuth when there is a hidden
service running
--------------------------+------------------------------------
 Reporter:  segfault      |          Owner:
     Type:  defect        |         Status:  new
 Priority:  Medium        |      Milestone:
Component:  Core Tor/Tor  |        Version:  Tor: 0.2.9.2-alpha
 Severity:  Normal        |     Resolution:
 Keywords:                |  Actual Points:
Parent ID:                |         Points:
 Reviewer:                |        Sponsor:
--------------------------+------------------------------------
Changes (by segfault):

 * status:  needs_information => new


Old description:

> When the sandbox is enabled and there is a hidden service configured,
> setting HidServAuth via SETCONF results in a permission error.
>
> Steps to reproduce:
>
> Start Tor with a hidden service:
>
> {{{
> /usr/bin/tor --defaults-torrc /usr/share/tor/tor-service-defaults-torrc
> --RunAsDaemon 0 --Log debug --CookieAuthentication 0  --Sandbox 1
> --HiddenServiceDir /var/lib/tor/hidden_service/ --HiddenServicePort 80 >
> tor.log
> }}}
>
> Try setting HidServAuth via the control port:
>
> {{{
> echo "AUTHENTICATE
> SETCONF HidServAuth=\"prkszpeygn2a3kxo.onion iGwsXkMwZEHuq/0YCD6IGQ\"" |
> nc -U /var/run/tor/control
> }}}
>
> Output:
>
> {{{
> 250 OK
> 513 Unacceptable option value: Failed to configure rendezvous options.
> See logs for details.
> }}}
>
> Log:
>
> {{{
> Aug 27 15:31:55.000 [warn] Directory /var/lib/tor/hidden_service/ cannot
> be read: Permission denied
> Aug 27 15:31:55.000 [warn] Controller gave us config lines that didn't
> validate: Failed to configure rendezvous options. See logs for details.
> }}}
>
> If we start Tor without a hidden service, it works without errors:
>
> {{{
> /usr/bin/tor --defaults-torrc /usr/share/tor/tor-service-defaults-torrc
> --RunAsDaemon 0 --Log debug --CookieAuthentication 0  --Sandbox 1 >
> tor.log
> }}}
>
> Set HidServAuth via the control port:
>
> {{{
> echo "AUTHENTICATE
> SETCONF HidServAuth=\"prkszpeygn2a3kxo.onion iGwsXkMwZEHuq/0YCD6IGQ\"" |
> nc -U /var/run/tor/control
> }}}
>
> Output:
>
> {{{
> 250 OK
> 250 OK
> }}}

New description:

 When the sandbox is enabled and there is a hidden service configured,
 setting HidServAuth via SETCONF results in a permission error.

 Steps to reproduce:

   Start Tor with a hidden service:

 {{{
 /usr/bin/tor --defaults-torrc /usr/share/tor/tor-service-defaults-torrc
 --RunAsDaemon 0 --Log debug --CookieAuthentication 0  --Sandbox 1
 --HiddenServiceDir /var/lib/tor/hidden_service/ --HiddenServicePort 80
 }}}
   Try setting HidServAuth via the control port:

 {{{
 echo "AUTHENTICATE
 SETCONF HidServAuth=\"prkszpeygn2a3kxo.onion iGwsXkMwZEHuq/0YCD6IGQ\"" |
 nc -U /var/run/tor/control
 }}}
   Output:

 {{{
 250 OK
 513 Unacceptable option value: Failed to configure rendezvous options. See
 logs for details.
 }}}
   Log:

 {{{
 Aug 27 15:31:55.000 [warn] Directory /var/lib/tor/hidden_service/ cannot
 be read: Permission denied
 Aug 27 15:31:55.000 [warn] Controller gave us config lines that didn't
 validate: Failed to configure rendezvous options. See logs for details.
 }}}
 If we start Tor without a hidden service or without the sandbox, it works
 without errors:

   Without hidden service:

 {{{
 /usr/bin/tor --defaults-torrc /usr/share/tor/tor-service-defaults-torrc
 --RunAsDaemon 0 --Log debug --CookieAuthentication 0  --Sandbox 1
 }}}
   or without sandbox:

 {{{
 /usr/bin/tor --defaults-torrc /usr/share/tor/tor-service-defaults-torrc
 --RunAsDaemon 0 --Log debug --CookieAuthentication 0  --Sandbox 0
 --HiddenServiceDir /var/lib/tor/hidden_service/ --HiddenServicePort 80
 }}}
   Set HidServAuth via the control port:

 {{{
 echo "AUTHENTICATE
 SETCONF HidServAuth=\"prkszpeygn2a3kxo.onion iGwsXkMwZEHuq/0YCD6IGQ\"" |
 nc -U /var/run/tor/control
 }}}
   Output:

 {{{
 250 OK
 250 OK
 }}}

--

Comment:

 > What happens when you turn sandbox off and hidden service auth on?
 Without the sandbox it works as expected. I updated the description to
 include this case.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/20007#comment:4>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
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