NetShareEnum: disable sanity check for better compatibility with Windows

[Giovanni Bajo]

Hello,

the attached patches increase Samba compatibility with Windows by
disabling a sanity check which prevents Samba from issuing an answer to
a NetShareEnum request in case of a corrupted (invalid) packet.

Long version. I have recently bought a Samsung BD-P3600 bluray player.
This unit has wired/wifi connection and a primitive/buggy support for
streaming files off Windows shares. It works well if the shares are on a
Windows PC, but it fails to detect shares on Linux and Mac OSX. I
investigated the problem and it turns out that the bluray player sends
an invalid packet:

0000  00 1b fc 91 80 08 00 12  fb 2a d9 7c 08 00 45 00   ........ .*.|..E.
0010  00 9e b8 2e 40 00 40 06  fe c2 c0 a8 01 17 c0 a8   .... at .@. ........
0020  01 01 cc 54 00 8b 46 cc  34 d6 de 00 9f ae 80 18   ...T..F. 4.......
0030  0b 68 01 e3 00 00 01 01  08 0a 00 00 99 c7 00 64   .h...... .......d
0040  41 2d 00 00 00 66 ff 53  4d 42 25 00 00 00 00 08   A-...f.S MB%.....
0050  01 00 00 00 00 00 00 00  00 00 00 00 00 00 01 00   ........ ........
0060  3b 00 00 00 9f 00 0e 1a  00 00 00 63 00 ff ff 00   ;....... ...c....
0070  00 00 00 00 00 00 00 00  00 1a 00 4c 00 00 00 66   ........ ...L...f
0080  00 00 00 27 00 5c 50 49  50 45 5c 4c 41 4e 4d 41   ...'.\PI PE\LANMA
0090  4e 00 00 00 57 72 4c 65  68 00 42 31 33 42 57 7a   N...WrLe h.B13BWz
00a0  57 57 57 7a 42 39 42 00  01 00 ff ff               WWWzB9B. ....

Microsoft Windows Lanman Remote API Protocol
  Function Code: NetShareEnum (0)
  Parameter Descriptor: WrLeh
  Return Descriptor: B13BWzWWWzB9B
  Detail Level: 1
  Receive Buffer Length: 65535

This packet is malformed because, for level 1 query, the correct return
descriptor would be "B13BWz". I've attached the full wireshark dump, in
case it matters.

What happens is that Samba refuses to answer to this query because it
fails an internal sanity check; instead, Windows happily answers and the
conversation goes on.

I verified my fix against a samba2 server (this is what I'm running on
my DDWRT-based router), and forward-ported the same patch on samba3 and
samba4 trees by visual inspection.

This is my first contribution to Samba, so I'm looking for some guidance
for this patch to be accepted.

Thanks!
-- 
Giovanni Bajo
Develer S.r.l.
http://www.develer.com

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