Re: [reSIProcate] Resiprocate/DUM assert hit when rearrenged/lost packets received

[Scott Godin <sgodin@xxxxxxxxxxxxxxx>]

Hi Szo,

Thanks for the reminder on this issue.

The log output (at DEBUG level) from BasicCall would make things much easier for someone to troubleshoot, without needing to setup the test.

Scott

On Thu, Jul 13, 2017 at 9:33 AM, Szokovacs Robert <robert.szokovacs@xxxxxxxxxxx> wrote:

Hello all,

We still have this problem and I still can't solve it unfortunately :(
I have created a barebones testcase that reproduces the scenarios.
The attached sipp scenario XMLs should be run like:

./sipp -i 127.0.0.1 -p 12010 -sf refer100.xml
or
./sipp -i 127.0.0.1 -p 12010 -sf refer.xml

and run the  BasicCall from resip/dum/test patched with the attached
diff. This test app has only one leg, the client leg in my original
post, and I simulated the BYE from the "A" leg with end() in the
onNewSubscriptionFromRefer(). The BasicCall app will crash and produce
the stacktrace I described below.

Please take a look!

TIA

br

Szo

On 2016-11-11 11:41, Szokovacs Robert wrote:
> Hi all,
>
> We have found a situation where a malicious third party possibly can
> crash the resiprocate based application by carefully rearranging SIP
> packets.
>
> We have the following setup: the resiprocate-based B2BUA receives the
> incoming call, calls the application server on an other leg, which,
> after some processing, REFERs the call towards it's final destination.
>
> Relevant packet flow:
>
> 1, A leg -> INVITE -> B2BUA
>
> 2, A leg <- 100 <- B2BUA
>
> 3, A leg <- 200OK <- B2BUA
>
> 4, B2BUA -> INVITE -> AppServer
>
> 5, B2BUA <- 100 <- AppServer
>
> 6, B2BUA <- 200OK <- AppServer
>
> 7, B2BUA -> ACK -> AppServer
>
> 8, B2BUA <- REFER <- AppServer
>
> 9, B2BUA -> 202 -> AppServer
>
> Etc, etc.
>
>
> In our situation packet #6 got lost and for reasons not important here
> the AppServer doesn't wait for ACK (#7) before sending the #8 REFER, #9
> is 491 instead of 202. All this is fine and correct behaviour; the
> problem manifests when the A leg sends BYE, causing our B2BUA to end the
> B leg too (bye calling AppDialogSet::end(), which in turn calls
> DialogSet::end() ), before #6 was retransmitted and received. Upon
> receiving the BYE, our app crashed:
>
> #16 in resip::Dialog::cancel (this=<optimized out>) at Dialog.cxx:341
>
> line 338: void
> Dialog::cancel()
> {
>    resip_assert(mType == Invitation);
>    ClientInviteSession* uac =
> dynamic_cast<ClientInviteSession*>(mInviteSession);
>    resip_assert (uac);
>    uac->cancel();
> line 345: }
>
> #17 in resip::DialogSet::end (this=0x874a27) at DialogSet.cxx:987
>
> line 983: for (DialogMap::iterator it = mDialogs.begin(); it !=
> mDialogs.end(); it++)
>                {
>                   try
>                   {
>                      it->second->cancel();
>                   }
>                   catch (UsageUseException& e)
>                   {
>                      InfoLog(<< "Caught: " << e);
>                   }
> line 993:   }
>
>
> Further investigation uncovered an other situation, when both #5 and #6
> is missing and not retransmitted, we hit a different assert, when the
> timeout generates the internal 408 response:
>
> #3  in __GI___assert_fail (assertion=0x875e85 "mDialogs.empty()",
> file=0x85b510 "DialogSet.cxx", line=352, function=0x8768c0 "void
> resip::DialogSet::dispatch(const resip::SipMessage&)") at assert.c:103
> #4  in resip::DialogSet::dispatch (this=0x7efec001f8d0, msg=...) at
> DialogSet.cxx:352
>
> line 350:  if (mState == WaitingToEnd)
>    {
>       resip_assert(mDialogs.empty());
>       if (msg.isResponse())
> line 354:  {
>
> #5  in resip::DialogUsageManager::processResponse (this=<optimized out>,
> response=...) at DialogUsageManager.cxx:2173
> #6  in resip::DialogUsageManager::incomingProcess (this=0x7efefa6690c0,
> msg=...) at DialogUsageManager.cxx:1680
> #7  in resip::DialogUsageManager::internalProcess (this=0x7efefa6690c0,
> msg=...) at DialogUsageManager.cxx:1486
> #8  in resip::DialogUsageManager::process (this=0x7efefa6690c0,
> mutex=<optimized out>) at DialogUsageManager.cxx:1710
>
>
> What common in these scenarios is that the DialogSet has unexpected
> Dialogs hanging around (in the wrong state in the first case, existing
> at all in the second). We think the root of the problem is that after
> DUM sends the 491 response to the wayward REFER, it should get rid of
> the corresponding Dialog, but for some reason, doesn't. We don't see
> where would it fit naturally to do it, so we have no patch proposal yet,
> please comment, advise!
>
> Thanks in advance!
>
> br
>
> Szo
>

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