[cifs-protocol] [REG: 110080417580961] [MS-BKRP] 3.1.4.1 "misc" 0x00020000 value
Edgar Olougouna
edgaro at microsoft.com
Thu Aug 5 15:42:07 MDT 2010
Hi Matthieu,
I will working with you to clarify this "misc" value you experienced regarding the BackupKey protocol.
Best regards,
Edgar
Issue verbatim
------------------
So page 31 of MS-BKRP.pdf state that the message format for exchange is :
NET_API_STATUS BackuprKey(
[in] handle_t h,
[in] GUID* pguidActionAgent,
[in, size_is(cbDataIn)] byte* pDataIn,
[in] DWORD cbDataIn,
[out, size_is(,*pcbDataOut)] byte** ppDataOut,
[out] DWORD* pcbDataOut,
[in] DWORD dwParam
);
I already asked if there is not some bytes after the dwParam.
After analyzing the out message I have the impression that before the
ppDataOut there is some kind of integer.
Here is the hex dump of an output message:
00000000 00 00 02 00 44 00 00 00 00 00 00 00 8d 65 cd e4
|....D........e..|
00000010 6c 93 62 22 48 e7 04 ff 0c 8f 0e 83 7a e4 dd d4
|l.b"H.......z...|
00000020 4b d1 8e 74 95 67 4f 85 be a5 9c b7 7f fd 39 2c
|K..t.gO.......9,|
00000030 54 bc a7 60 e4 e0 13 26 49 6f ca 35 ee bb 23 24
|T..`...&Io.5..#$|
00000040 51 d4 4e c9 37 1d f0 9e 83 69 bd 10 44 00 00 00
|Q.N.7....i..D...|
00000050 00 00 00 00 |....|
00000054
so from byte 4 (0x44 ) we have clearly (at least to me) the ppDataOut
variable that is NDR encoded (meaning that the size is specified before
on the wire) up to byte 4B then we have the size (pcbDataOut) (0x44 0x00
0x00 0x00) and then the return code.
I attach the out message extracted from the trace I sent last time.
With the following samba idl:
[public,nopush,nopull,noprint] WERROR bkrp_BackupKey (
[in,ref] GUID *guidActionAgent,
[in,ref] [subcontext(4)] uint8 *data_in,
[in] uint32 data_in_len,
[in] uint32 param,
[out] uint32 misc,
[out] DATA_BLOB secret,
[out] uint32 data_out_len
);
We have the following result while using our ndrdump tool:
pull returned NT_STATUS_OK
bkrp_BackupKey: struct bkrp_BackupKey
out: struct bkrp_BackupKey
misc : 0x00020000 (131072)
secret : DATA_BLOB length=68
data_out_len : 0x00000044 (68)
result : WERR_OK
dump OK
As I have also managed to get a correct
BACKUPKEY_RETRIEVE_BACKUP_KEY_GUID exchange I also witnessed that on
the out message there is also "something" (that I named misc in our idl)
(see the get_key_out file which is the extraction of out message on a
BACKUPKEY_RETRIEVE_BACKUP_KEY_GUID request). As the certificate that I
extracted seems to be correct I pretty encline to think I am right as
first we are able to parse the NDR encoded data, and that the result
seems sensible.
Can you see if my analysis is correct and if so can you give us the
explanation of this "misc" parameter. If not, well please tell me the
correct way to parse the message.
-----Original Message-----
From: Bryan Burgin
Sent: Wednesday, August 04, 2010 10:12 PM
To: 'mat at samba.org'
Cc: pfif at tridgell.net; cifs-protocol at samba.org; MSSolve Case Email
Subject: RE: [REG:110071868986368] unused bytes after while decoding bkrp requests
Matthieu,
For your new issues, I created three new cases and dispatched them across the team
110080417580961
[MS-BKRP] 3.1.4.1 "misc" 0x00020000 value
110080418016869
[MS-BKRP] 3.1.4.1.3 -- version field and a GUID field no documented
110080418357322
[MS-BKRP] 1.3.1 -- in a given domain there is only "active" rsa key
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