2.2.7.1.1 Client Request Extensions

An SMB_COM_NT_TRANSACT (section 2.2.4.8) command with an NT_TRANSACT_CREATE subcommand is sent by a client to open a file or device on the server. The NT_TRANSACT_CREATE subcommand is specified in [MS-CIFS] section 2.2.7.1. This extension adds the following:

  • An additional flag bit is added to the Flags field. The additional flag, NT_CREATE_REQUEST_EXTENDED_RESPONSE, is used to request an extended response from the server.

  • An additional parameter value, SECURITY_DELEGATION, is added to the ImpersonationLevel field.

  • An additional flag bit is added to the CreateOptions field. The additional flag, FILE_OPEN_REPARSE_POINT, is used to open a reparse point file itself.

All other fields are as specified in [MS-CIFS] section 2.2.7.1.

 NT_Trans_Parameters
   {
   ULONG         Flags;
   ULONG         RootDirectoryFID;
   ULONG         DesiredAccess;
   LARGE_INTEGER AllocationSize;
   SMB_EXT_FILE_ATTR ExtFileAttributes;
   ULONG         ShareAccess;
   ULONG         CreateDisposition;
   ULONG         CreateOptions;
   ULONG         SecurityDescriptorLength;
   ULONG         EALength;
   ULONG         NameLength;
   ULONG         ImpersonationLevel;
   UCHAR         SecurityFlags;
   UCHAR         Name[NameLength];
   }
 NT_Trans_Data
   {
   SECURITY_DESCRIPTOR      SecurityDescriptor;
   FILE_FULL_EA_INFORMATION ExtendedAttributes[];
   }

NT_Trans_Parameters (variable):


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Flags

RootDirectoryFID

DesiredAccess

AllocationSize (variable)

...

ExtFileAttributes

ShareAccess

CreateDisposition

CreateOptions

SecurityDescriptorLength

EALength

NameLength

ImpersonationLevel

SecurityFlags

Name (variable)

...

Flags (4 bytes): A 32-bit field containing a set of flags that modify the client request. Unused bits SHOULD be set to 0 by the client when sending a message and MUST be ignored when received by the server.

Name & bitmask

Meaning

NT_CREATE_REQUEST_OPLOCK

0x00000002

Level I (exclusive) OpLock requested.

NT_CREATE_REQUEST_OPBATCH

0x00000004

Batch OpLock requested.

NT_CREATE_OPEN_TARGET_DIR

0x00000008

Parent directory of the target is to be opened.

NT_CREATE_REQUEST_EXTENDED_RESPONSE

0x00000010

Extended information is requested in the response.

ImpersonationLevel (4 bytes): This field specifies the impersonation level requested by the application that is issuing the create request, and MUST contain one of the following values.

Impersonation is described in [MS-WPO] section 9.7; for more information about impersonation, see [MSDN-IMPERS].

Value

Meaning

SECURITY_ANONYMOUS

0x00000000

The application-requested impersonation level is Anonymous.

SECURITY_IDENTIFICATION

0x00000001

The application-requested impersonation level is Identification.

SECURITY_IMPERSONATION

0x00000002

The application-requested impersonation level is Impersonation.

SECURITY_DELEGATION

0x00000003

The application-requested impersonation level is Delegation.

CreateOptions (4 bytes): A 32-bit field containing flag options for creating a file or directory. In addition to the flags specified in [MS-CIFS] section 2.2.4.64, the following modifications and extensions apply to the CreateOptions field. FILE_OPEN_REPARSE_POINT is a new flag to SMB. The CreateOptions field MUST be set to 0x00000000 or to a combination of the flags specified in the [MS-CIFS] section 2.2.4.64 CreateOptions table and the following table. Unused bit fields SHOULD be set to 0 when sent and MUST be ignored on receipt. Server implementations SHOULD reserve all bits not specified in the [MS-CIFS] section 2.2.4.64 CreateOptions table and the following table.

Name and bitmask

Meaning

FILE_OPEN_REPARSE_POINT

0x00200000

If the file or directory being opened is a reparse point, open the reparse point itself rather than the target that the reparse point references.