[tor-commits] [tor/maint-0.3.4] If options_act() fails, restore the previous value of global_options

[nickm at torproject.org]

commit 281854bab7001cc838c91b521b41b666140e124f
Author: Nick Mathewson <nickm at torproject.org>
Date:   Fri Sep 14 10:34:45 2018 -0400

    If options_act() fails, restore the previous value of global_options
    
    Before 0.3.3.1-alpha, we would exit() in this case immediately.  But
    now that we leave tor_main() more conventionally, we need to make
    sure we restore things so as not to cause a double free.
    
    Fixes bug 27708; bugfix on 0.3.3.1-alpha.
---
 changes/bug27708 | 4 ++++
 src/or/config.c  | 1 +
 2 files changed, 5 insertions(+)

diff --git a/changes/bug27708 b/changes/bug27708
new file mode 100644
index 000000000..d283b1951
--- /dev/null
+++ b/changes/bug27708
@@ -0,0 +1,4 @@
+  o Major bugfixes (restart-in-process):
+    - Fix a use-after-free error that could be caused by passing Tor an
+      impossible set of options that would fail during options_act().
+      Fixes bug 27708; bugfix on 0.3.3.1-alpha.
diff --git a/src/or/config.c b/src/or/config.c
index ac37324a2..58080c65e 100644
--- a/src/or/config.c
+++ b/src/or/config.c
@@ -868,6 +868,7 @@ set_options(or_options_t *new_val, char **msg)
               "Acting on config options left us in a broken state. Dying.");
       tor_shutdown_event_loop_and_exit(1);
     }
+    global_options = old_options;
     return -1;
   }
   /* Issues a CONF_CHANGED event to notify controller of the change. If Tor is