UNIX Extensions

Revision as of 22:16, 27 February 2007 by Jpeach (talk | contribs) (SMB WHOAMI)

See http://samba.org/samba/CIFS_POSIX_extensions.html

All Unix extensions are TRANSACT2 commands in the range from 0x200 to 0x2FF (inclusive).

Negotiating Capabilities

Capability Value
CIFS_UNIX_FCNLT_LOCKS_CAP 0x01
CIFS_UNIX_POSIX_ACLS_CAP 0x02
CIFS_UNIX_XATTR_CAP 0x04
CIFS_UNIX_EXATTR_CAP 0x08
CIFS_UNIX_POSIX_PATH_OPERATIONS_CAP 0x20

Posix Open

The server specifies it can serve these by returning CIFS_UNIX_POSIX_PATH_OPERATIONS_CAP in the reply to a trans2 qfsinfo (TRANSACT2_QFSINFO 0x03) info level SMB_QUERY_CIFS_UNIX_INFO (0x200) call. All values are little endian.

For open, call TRANSACT2_SETPATHINFO (0x06) call info level :

SMB_POSIX_PATH_OPEN 0x209

The request data block should be 14 bytes consisting of the following :

Size Offset Value
4 bytes 0 Flags field (same as smb_ntcreate_flags in SMBNTCreateX to request oplocks)
4 bytes 4 POSIX open flags (see below)
4 bytes 8 POSIX mode_t (see below)
2 bytes 12 Reply info level requested (see below)

Encodings are as follows :

POSIX open flags Value
SMB_O_RDONLY 0x1
SMB_O_WRONLY 0x2
SMB_O_RDWR 0x4
SMB_O_CREAT 0x10
SMB_O_EXCL 0x20
SMB_O_TRUNC 0x40
SMB_O_APPEND 0x80
SMB_O_SYNC 0x100
SMB_O_DIRECTORY 0x200
SMB_O_NOFOLLOW 0x400
SMB_O_DIRECT 0x800

SMB WHOAMI

The SMBWhoami extension is intended to be a lightweight method for a Unix client to be able to display sensible file ownership information.

SMBWhoami is performed by requesting a TRANS2_QFSINFO with an info level of SMB_QUERY_POSIX_WHOAMI. There are no parameters passed. The vuid field is implicitly used.

  1. define SMB_QUERY_POSIX_WHOAMI 0x202
SMB_QUERY_POSIX_WHOAMI 0x202


+ SMB_WHOAMI_GUEST = 0x1 /* Logged in as (or squashed to) guest */

Size Offset Value
4 bytes 0 Mapping flags
4 bytes 4 Mask of valid mapping flags
8 bytes 8 Primary user ID
8 bytes 16 Primary group ID
4 bytes 24 number of supplementary GIDs
4 bytes 28 number of SIDs
4 bytes 32 SID list byte count
4 bytes 36 Reserved (should be zero)
variable ... list of 8 byte group IDs (may be empty)
variable ... List of DOM_SID structures (may be empty)

UNIX_INFO2