linux/fs/cifs/cifsacl.h

/*
 *   fs/cifs/cifsacl.h
 *
 *   Copyright (c) International Business Machines  Corp., 2007
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published
 *   by the Free Software Foundation; either version 2.1 of the License, or
 *   (at your option) any later version.
 *
 *   This library is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *   the GNU Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#ifndef _CIFSACL_H
#define _CIFSACL_H


#define NUM_AUTHS (6)	/* number of authority fields */
#define SID_MAX_SUB_AUTHORITIES (15) /* max number of sub authority fields */

#define READ_BIT        0x4
#define WRITE_BIT       0x2
#define EXEC_BIT        0x1

#define UBITSHIFT	6
#define GBITSHIFT	3

#define ACCESS_ALLOWED	0
#define ACCESS_DENIED	1

#define SIDOWNER 1
#define SIDGROUP 2

/*
 * Security Descriptor length containing DACL with 3 ACEs (one each for
 * owner, group and world).
 */
#define DEFAULT_SEC_DESC_LEN (sizeof(struct cifs_ntsd) + \
			      sizeof(struct cifs_acl) + \
			      (sizeof(struct cifs_ace) * 3))

/*
 * Maximum size of a string representation of a SID:
 *
 * The fields are unsigned values in decimal. So:
 *
 * u8:  max 3 bytes in decimal
 * u32: max 10 bytes in decimal
 *
 * "S-" + 3 bytes for version field + 15 for authority field + NULL terminator
 *
 * For authority field, max is when all 6 values are non-zero and it must be
 * represented in hex. So "-0x" + 12 hex digits.
 *
 * Add 11 bytes for each subauthority field (10 bytes each + 1 for '-')
 */
#define SID_STRING_BASE_SIZE (2 + 3 + 15 + 1)
#define SID_STRING_SUBAUTH_SIZE (11) /* size of a single subauth string */

struct cifs_ntsd {
	__le16 revision; /* revision level */
	__le16 type;
	__le32 osidoffset;
	__le32 gsidoffset;
	__le32 sacloffset;
	__le32 dacloffset;
} __attribute__((packed));

struct cifs_sid {
	__u8 revision; /* revision level */
	__u8 num_subauth;
	__u8 authority[NUM_AUTHS];
	__le32 sub_auth[SID_MAX_SUB_AUTHORITIES]; /* sub_auth[num_subauth] */
} __attribute__((packed));

/* size of a struct cifs_sid, sans sub_auth array */
#define CIFS_SID_BASE_SIZE (1 + 1 + NUM_AUTHS)

struct cifs_acl {
	__le16 revision; /* revision level */
	__le16 size;
	__le32 num_aces;
} __attribute__((packed));

struct cifs_ace {
	__u8 type;
	__u8 flags;
	__le16 size;
	__le32 access_req;
	struct cifs_sid sid; /* ie UUID of user or group who gets these perms */
} __attribute__((packed));

/*
 * Minimum security identifier can be one for system defined Users
 * and Groups such as NULL SID and World or Built-in accounts such
 * as Administrator and Guest and consists of
 * Revision + Num (Sub)Auths + Authority + Domain (one Subauthority)
 */
#define MIN_SID_LEN  (1 + 1 + 6 + 4) /* in bytes */

/*
 * Minimum security descriptor can be one without any SACL and DACL and can
 * consist of revision, type, and two sids of minimum size for owner and group
 */
#define MIN_SEC_DESC_LEN  (sizeof(struct cifs_ntsd) + (2 * MIN_SID_LEN))

#endif /* _CIFSACL_H */