我一直在修改“检查”WFP 示例(与 WinDDK 捆绑在一起),目的是能够解析所有传入 TCP 数据包(来自指定 IP 地址)的有效负载以获取某些字符串。(我已经修改了“检查”,使得过滤器只捕获 TCP 数据包)
到目前为止,我的修改一直在'TLInspectTransportClassify'classifyFn上,如下所示。我的目标是访问捕获的每个 TCP 数据包的有效负载。
FWPS_STREAM_CALLOUT_IO_PACKET* ioPacket = (FWPS_STREAM_CALLOUT_IO_PACKET*)layerData;
FWPS_STREAM_DATA* streamData;
SIZE_T streamLength;
BYTE* stream = NULL;
SIZE_T bytesCopied = 0;
[...]
if(ioPacket == NULL) {
DbgPrint("ioPacket == NULL\n");
return STATUS_INSUFFICIENT_RESOURCES;
}
streamData = ioPacket->streamData;
if(!streamData) { // why is this always NULL? shouldn't our payload be here?
DbgPrint("streamData == NULL: no data\n");
classifyOut->actionType = FWP_ACTION_PERMIT;
classifyOut->rights &= ~FWPS_RIGHT_ACTION_WRITE;
goto Exit;
}
DbgPrint("tcp packet has some data\n");
streamLength = streamData->dataLength;
stream = ExAllocatePoolWithTag(NonPagedPool,
streamLength,
'yftN');
if (!stream)
return STATUS_INSUFFICIENT_RESOURCES;
RtlZeroMemory(stream,streamLength);
FwpsCopyStreamDataToBuffer0(
streamData,
stream,
streamLength,
&bytesCopied);
// should now have our tcp payload in 'stream' buffer(?)
DbgPrint("reached parsing code\n");
[...]
据我了解,在如上所述声明 ioPacket 之后,ioPacket->streamData 应该包含数据包的有效负载。但是,ioPacket->streamData 对我来说始终为 NULL。如何获取数据包的有效负载?难道我做错了什么。
提前致谢。