large writes and reads ...

Richard Sharpe rsharpe at
Sun Oct 17 05:58:08 GMT 2004

On Fri, 15 Oct 2004, Jeremy Allison wrote:

> > Well, it seems that both reply_read_and_X and reply_write_and_X in
> > smbd/reply.c for the current Samba 3 code ignores large reads and writes.
> >
> > That is, they both ignore the Max Count High field for reads and the Data
> > Length High field for writes if the WCT is not 14 for each of these.
> >
> > Indeed, reply_read_and_X ignores the Max Count High field altogether, as
> > all it does is:
> >
> >         size_t smb_maxcnt = SVAL(inbuf,smb_vwv5);
> >
> > and does not add in the high field under any circumstances, even though
> > Samba claims to support Large Read&X in the capabilities field of the
> > NegProt response.
> >
> > The code in reply_write_and_X only pays attention to the Lenght High Field
> > if the WCT is 14, which seems just wrong ...
> Are you sure ? There were some bugs in the spec here. Don't go by what
> the spec says, test it in the Samba4 test suite against W2K3 first...

Well, now I am sure that Windows ignores anything in the MaxCountHigh for
the wct=10 variant of Read&X and the wct=12 variant of Write&X.

I am having problems provoking large reads from Windows as well to see
what it does, and Samba 4 does not seem to understand the high count
fields, but I have not looked at the torture tests as yet.

Richard Sharpe, rsharpe[at], rsharpe[at],

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