[Quickfix-developers] Re: Infinite loop when receiving bad message in threaded acceptor

[Oren M. <or...@qu...>]

Garbled messages should be ignored, so it shouldn't cause a termination =
of the session. If it goes on to continue reading the buffer, then that =
is the correct behavior according to the FPL test cases.

--oren
  ----- Original Message -----=20
  From: Yihu Fang=20
  To: Yihu Fang ; Oren Miller ; =
qui...@li...=20
  Sent: Tuesday, February 22, 2005 2:45 PM
  Subject: RE: Infinite loop when receiving bad message in threaded =
acceptor


  Hi,

  =20

  To stop the infinite loop, in catch(MessageParseError &e) of =
Parser::readFixMessage(), the m_buffer should be emptied. Because pos =
and length are zero, the bad message in m_buffer is reused which causes =
the infinite loop.

  =20

  QuickFIX 1.9.4

  117,118c117

  <     // m_buffer.erase( 0, pos + length );

  <         m_buffer.erase();

  ---

  >     m_buffer.erase( 0, pos + length );

  =20

  Whether QF is going to decide to terminate the session or not should =
be done in the ThreadedSocketConnection.

  =20

  Thanks,

  =20

  -Yihu

  =20


-------------------------------------------------------------------------=
-----

  From: Yihu Fang=20
  Sent: Tuesday, February 22, 2005 2:09 PM
  To: 'Oren Miller'; qui...@li...
  Subject: Infinite loop when receiving bad message in threaded acceptor

  =20

  Oren,

  =20

  When a threaded acceptor receives a garbled message, e.g. invalid =
length field, during an established FIX session, the QuickFIX engine =
runs into an infinite loop.

  =20

  An example garbles message is like this, =
8=3DTEST9=3DTEST35=3DTEST49=3DSS156=3DRORE34=3D352=3D20050222-16:45:5310=3D=
TEST

  =20

  Parser::extractLength() throws a MessageParserError exception because =
of field 9=3DTEST.

  =20

  ThreadSocketConnection::readMessage() catches the exception but it =
does nothing and returns true.

  =20

  This causes an infinite loop in the =
ThreadedSocketConnection::readQueue(). An empty string is passed to =
Session::next(), an InvalidMessage exception is thrown. However, because =
the session is in a logon on state, the session is not disconnected, but =
keeps going.

  =20

  The session should be disconnected in the exception catch of either =
MessageParserError or InvalidMessage.

  =20

  Thank you,

  =20

  -Yihu



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