[tor-bugs] #32877 [Core Tor/Tor]: Sandbox crash when reloading log configuration

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#32877: Sandbox crash when reloading log configuration
--------------------------+------------------------------
 Reporter:  pege          |          Owner:  (none)
     Type:  defect        |         Status:  new
 Priority:  Medium        |      Component:  Core Tor/Tor
  Version:  Tor: 0.4.2.5  |       Severity:  Normal
 Keywords:                |  Actual Points:
Parent ID:                |         Points:
 Reviewer:                |        Sponsor:
--------------------------+------------------------------
 A sandbox related crash was reported on the tor-relay mailing list. I'm
 currently looking into the issue and I expect to have a fix ready soon.

 Original report:

 -----

 Subject: [tor-relays] tor crash on HUP only when SANDBOX is 1
 Date: Sun, 5 Jan 2020 07:43:45 +0100
 From: tor-relay at ...
 Reply-To: tor-relays at lists.torproject.org
 To: tor-relays at lists.torproject.org

 Hi,

 I'm running an exit relay on a Debian Buster. I installed libseccomp and
 I've built tor 0.4.2.5 using debuild, like the wiki says.

 Today I noticed that tor crashes on HUP signal, only when the Sandbox
 option is on. I never had this problem.


 This is what my log says:

 an 05 08:23:10.000 [notice] Received reload signal (hup). Reloading config
 and resetting internal state.
 Jan 05 08:23:10.000 [notice] Read configuration file "/usr/share/tor/tor-
 service-defaults-torrc".
 Jan 05 08:23:10.000 [notice] Read configuration file "/etc/tor/torrc".
 Jan 05 08:23:10.000 [notice] Tor 0.4.2.5 opening log file.

 ============================================================ T= 1578205390
 (Sandbox) Caught a bad syscall attempt (syscall dup)
 /usr/bin/tor(+0x1fc9fa)[0x561d896b29fa]
 /lib/x86_64-linux-gnu/libc.so.6(dup+0x7)[0x7f0bebf4bbc7]
 /lib/x86_64-linux-gnu/libc.so.6(dup+0x7)[0x7f0bebf4bbc7]
 /usr/bin/tor(tor_log_update_sigsafe_err_fds+0x18b)[0x561d896c699b]
 /usr/bin/tor(set_options+0x3c0)[0x561d89642f80]
 /usr/bin/tor(options_init_from_string+0x17d)[0x561d896453dd]
 /usr/bin/tor(options_init_from_torrc+0x404)[0x561d89645a74]
 /usr/bin/tor(+0x5f961)[0x561d89515961]
 /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6(+0x22a6c)[0x7f0bec5a3a6c]
 /usr/lib/x86_64-linux-
 gnu/libevent-2.1.so.6(event_base_loop+0x5a7)[0x7f0bec5a4537]
 /usr/bin/tor(do_main_loop+0xff)[0x561d8952a3af]
 /usr/bin/tor(tor_run_main+0x1105)[0x561d89517d55]
 /usr/bin/tor(tor_main+0x3a)[0x561d8951523a]
 /usr/bin/tor(main+0x19)[0x561d89514df9]
 /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xeb)[0x7f0bebe8509b]
 /usr/bin/tor(_start+0x2a)[0x561d89514e4a]

 I'm telling you because i think it could be a bug, but I'm not sure that
 It's not caused by something else.

 At the moment I've disabled Sandbox. Please, let me know if I can fix this
 in some way, thanks.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/32877>
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