BUG in enumprinterdataex

[Martin]

Jeremy Allison wrote:
> On Fri, Feb 02, 2007 at 10:34:34AM +0100, Martin Zielinski wrote:
>> Hello,
>>
>> i can observe the following situation on XP SP2 vs. Samba 3.0.23d:
>>
>> 1) XP does an EnumPrinterDataEx call with 0 bytes provided to Samba
>> 2) Samba counts the space needed and returns a *not 4-byte aligned* 
>> amount of space (I can see it on the wire - e.g. 1642)
>> 3) XP returns a 4-byte aligned value in the EnumPrinterDataEx - call.
>> In the above case: 1644
>> 4) The routine allocates 1644 bytes, does the call again and receives a
>> 	RPC_X_BAD_STUB_DATA (0x6f7 = 1783) error.
>>   Weird thing while debugging: I see the provided key name corrupted.
>>
>> The reason for this seems to be the returned buffer size in the RPC 
>> response.
>> The attached diff fixes this for the enumprinterdataex call.
> 
> Ok, I'm going to commit this one - makes sense to me. A problem
> with hand marshalling I think.
> 
>> P.S. I'm really not shure - but haven't we had this one before?
> 
> Not sure - this code will eventually greatly benefit from
> being PIDL generated. Please keep these fixes coming :-).
> 
>> --- orig/srv_spoolss_nt.c	2007-02-02 10:27:15.000000000 +0100
>> +++ work/srv_spoolss_nt.c	2007-02-02 10:28:03.000000000 +0100
>> @@ -9389,6 +9389,8 @@
>>  	/* copy data into the reply */
>>  	
>>  	r_u->ctr.size        	= r_u->needed;
>> +	if (needed % 4)
>> +		r_u->ctr.size += 4-(needed % 4);
>>  	r_u->ctr.size_of_array 	= r_u->returned;
>>  	r_u->ctr.values 	= enum_values;
>>  	
> 
> Thanks !
> 
> Jeremy.
> 
Hi!
I certainly trapped vista again.
The proposed fix works with XP but not with Vista.
Easy to compare: Samba returns a buffer size of 1642 bytes.
-> XP offers a buffer of 1644 bytes.
-> Vista 1642 bytes.

If we only align the buffer size (as in the proposed patch), we earn a 
1783 error. It seems that the buffer size in the RPC *must* match the 
"needed" size in the message itself.

So the better fix would be to align the "needed" var before the test
against the input size.

Martin