[tor-bugs] #13893 [Applications/Tor Browser]: Torbrowser crashes on start when using MS EMET 5.x

Tor Bug Tracker & Wiki blackhole at torproject.org
Tue Oct 18 17:40:42 UTC 2016

#13893: Torbrowser crashes on start when using MS EMET 5.x
 Reporter:  Diapolo                              |          Owner:  gk
     Type:  defect                               |         Status:
                                                 |  reopened
 Priority:  High                                 |      Milestone:
Component:  Applications/Tor Browser             |        Version:
 Severity:  Major                                |     Resolution:
 Keywords:  tbb-security, tbb-crash, tbb-        |  Actual Points:
  usability-stoppoint-app, fuck-mingw-gcc,       |
  GeorgKoppen201609, TorBrowserTeam201610,       |
  ff52-esr                                       |
Parent ID:  #12820                               |         Points:
 Reviewer:                                       |        Sponsor:

Comment (by gk):

 Replying to [comment:87 bugzilla]:
 > Replying to [comment:86 gk]:
 > > Replying to [comment:85 bugzilla]:
 > > > Replying to [comment:84 gk]:
 > > > > I think Tor Browser started for all of them (see comment:73,
 comment:75 and I tested it on my machines as well) and it worked with GCC
 6 while it did not without it.
 > > > Have you reverted https://hg.mozilla.org/releases/mozilla-
 aurora/rev/7d7176ca2470 to test `IOInterposer`?
 > > No.
 > > > Have you seen the requirements for invoking
 > > Yes. Not sure what you want to point out.
 > That you didn't make the conditions to properly test for
 VirtualProtectEx calls.
 > >
 > > No. But what I did was compiling our latest 45.4.0esr code once with
 GCC < 6 and once with GCC 6 and the latter allowed me to run Tor Browser
 with EMET while the former not. *All* other things were equal.
 > If EMET can't detect vulnerabilities at startup, it doesn't mean they
 are gone.

 Not sure what you mean. The difference I outlined is the one between a not
 working Tor Browser (compiled with GCC < 6) with EMET protections enabled
 and one that does work (compiled with GCC 6) while *all* other conditions
 are equal. And it is not about start-up only I tested the build while
 surfing for a while.

 > > > TBB freezes with EAF, nothing to discuss.
 > >
 > > You mean the nightly build I pointed you to? That worked pretty fine
 for me with all the EMET features enabled. Others reported that as well
 (and I assume they had all features enabled, too).
 > >
 > It's about security, not bells and whistles with shiny checkboxes to
 enable them all. You can't activate some features without entering custom
 > Any app freezes with EAF, even M$ sees it (see
 > Here is your nightly (plugin-container.exe):
 > {{{
 >   CodeAddress         : 0x5B387DC7
 >   CodeStackPtr        : 0x51ECA0
 >   CalledAddress       : 0x75BF0479
 >   API name    : kernel32.VirtualProtectEx
 >   StackPtr    : 0x0051EC20
 >   FramePtr    : 0x5CCE3324
 > }}}

 Works fine for me on my testing machines while the versions compiled with
 GCC < 6 are broken. EAF *is* enabled for what it is worth. So, maybe my
 machines are missing the Microsoft update that breaks EMET? But if that's
 the case and this is indeed affecting *any* application as you mentioned
 then there is nothing we can do from Tor Browser land to fix that. We can
 only mention it in #12820 I guess.

Ticket URL: <https://trac.torproject.org/projects/tor/ticket/13893#comment:88>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online

More information about the tor-bugs mailing list