Qt application using QHttp becomes unstable after HTTP/HTTPS communication

Because of the wrong use of winsock2 function "WSASocket()" inside the Qt network library, Qt applications using QHttp become unstable after HTTP/HTTPS communication.

The details:
1. Application becomes unresponsive while CPU usage climbs to 100% after starting the HTTP communication.
2. Application crashes from memory access violations or exceptions.

The code in the following source files causes this problem.

$QTDIR/src/network/qnativesocketengine_win.cpp (in Qt 4.3.4)
$QTDIR/src/network/socket/qnativesocketengine_win.cpp (in Qt 4.4.0)

bool QNativeSocketEnginePrivate::createNewSocket(QAbstractSocket::SocketType socketType,
QAbstractSocket::NetworkLayerProtocol socketProtocol)

0 is passed as the third argument of the function "WSASocket()" in the above function.

SOCKET socket = ::WSASocket(protocol, type, 0, NULL, 0, WSA_FLAG_OVERLAPPED);

In MSDN, it is stated that if a value of 0 is specified, the caller does not wish to specify a protocol and the service provider will choose the protocol to use.

If any non-IFS layered service provider installed on WinNT/Win2k/WinXP, in this case WSASocket() call selects the non-IFS LSP because Service Provider is not specified. However, it's not possible to use overlapped IO unless service provider is IFS-compatible.
As a result, application hangs.

It is possible to get sample LSP from MS Platform SDK and the details of WSASocket() are available from the following MSDN.

http://msdn.microsoft.com/en-us/library/ms742212(VS.85).aspx

A similar case has been found in ActivePerl. This bug(id 24269) is found in v5.8.1 and fixed in v5.8.6.

• 24269 socket() call uses non-IFS providers causing subsequent print/read to hang or misbehave
  http://www.nntp.perl.org/group/perl.perl5.porters/2003/12/msg86717.html
  http://rt.perl.org/rt3/Public/Bug/Display.html?id=24269

The following function is added to fix this problem in ActivePerl.
-------------------------------------------------------------------------------------------------
SOCKET
open_ifs_socket(int af, int type, int protocol)
{
unsigned long proto_buffers_len = 0;
int error_code;
SOCKET out = INVALID_SOCKET;

if (WSCEnumProtocols(NULL, NULL, &proto_buffers_len, &error_code) == SOCKET_ERROR &&
error_code == WSAENOBUFS) {

WSAPROTOCOL_INFOW *proto_buffers = (WSAPROTOCOL_INFOW *) malloc(proto_buffers_len);
int protocols_available = 0;

if ((protocols_available = WSCEnumProtocols(NULL, proto_buffers,
&proto_buffers_len, &error_code)) != SOCKET_ERROR) {
int i;
for (i = 0; i < protocols_available; i++)

{ WSAPROTOCOL_INFOA proto_info; if ((af != AF_UNSPEC && af != proto_buffers[i].iAddressFamily) || (type != proto_buffers[i].iSocketType) || (protocol != 0 && protocol != proto_buffers[i].iProtocol)) continue; if ((proto_buffers[i].dwServiceFlags1 & XP1_IFS_HANDLES) == 0) continue; convert_proto_info_w2a(&(proto_buffers[i]), &proto_info); out = WSASocket(af, type, protocol, &proto_info, 0, 0); break; }

}

if (proto_buffers)
free(proto_buffers);
}

return out;
}
--------------------------------------------------------------------------------------------------
"QNativeSocketEnginePrivate::createNewSocket()" should be fixed in a similar way