[jcifs] Even-byte-alignment padding in Write AndX Request

[Michael B Allen]

On Thu, 15 Jul 2004 22:12:21 -0500
ddkilzer at kilzer.net (David D. Kilzer) wrote:

> I've now got a full packet returning via Read AndX Response!!  But I'm
> getting an IndexOutOfBoundsException now (such is progress):
> 
> java.lang.IndexOutOfBoundsException
> 	at java.io.PushbackInputStream.read(PushbackInputStream.java:143)
> 	at
> 	jcifs.smb.SmbComReadAndXResponse.readBytesDirectWireFormat(SmbComRe
> 	adAndXResponse.java:68) at
> 	jcifs.smb.AndXServerMessageBlock.readAndXWireFormat(AndXServerMessa
> 	geBlock.java:266) at
> 	jcifs.smb.AndXServerMessageBlock.readWireFormat(AndXServerMessageBl
> 	ock.java:103) at jcifs.smb.SmbTransport.run(SmbTransport.java:444)
> 	at java.lang.Thread.run(Thread.java:536)
> 
> A quick debugging session showed that the code is dying in line 3 of
> SmbComReadAndXResponse.readBytesDirectWireFormat() because 'b' is
> declared as byte[8] when 175 bytes of data are available to be read.
> Oops!  I don't have time to track that down just now, but I'm hoping
> that one of the developers can provide a patch fairly easily (or else
> I'll go play with JCIFS some more tomorrow).

That's kinda strange because b is SmbTransport.rcv_buf which is *hard
coded* with a size of 0xFFFF:

    private static byte[] rcv_buf = new byte[0xFFFF];

> BTW, the last change I made (which triggered the above exception) was to
> hard-code maxCount and minCount to 512 in the constructor and setParam()
> methods of SmbComReadAndX:
> 
>   this.maxCount = minCount = 512;
> 
> Turns out that SQL Server 6.5 will only send back the number of bytes
> requested by one (or both) of those fields, so when I was getting the
> other error message earlier, I was only getting 1 byte back instead of
> the whole TDS packet!

I don't follow.

  1) What does your jCIFS code look like to access the IPC resource? 
  2) Send captures.

It sounds like the pipe needs to be in a certain message mode that isn't
quite set right. There are many options for pipes. If they're not right it
might half work like you're seeing. I assume you have seen our named pipe
docs?

  http://jcifs.samba.org/src/docs/pipes.html

Mike

-- 
Greedo shoots first? Not in my Star Wars.