fs/cifs/cifsacl.h

   1 /*
   2  *   fs/cifs/cifsacl.h
   3  *
   4  *   Copyright (c) International Business Machines  Corp., 2007
   5  *   Author(s): Steve French (sfrench@us.ibm.com)
   6  *
   7  *   This library is free software; you can redistribute it and/or modify
   8  *   it under the terms of the GNU Lesser General Public License as published
   9  *   by the Free Software Foundation; either version 2.1 of the License, or
  10  *   (at your option) any later version.
  11  *
  12  *   This library is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  15  *   the GNU Lesser General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU Lesser General Public License
  18  *   along with this library; if not, write to the Free Software
  19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #ifndef _CIFSACL_H
  23 #define _CIFSACL_H
  24
  25
  26 #define NUM_AUTHS (6)   /* number of authority fields */
  27 #define SID_MAX_SUB_AUTHORITIES (15) /* max number of sub authority fields */
  28
  29 #define READ_BIT        0x4
  30 #define WRITE_BIT       0x2
  31 #define EXEC_BIT        0x1
  32
  33 #define UBITSHIFT       6
  34 #define GBITSHIFT       3
  35
  36 #define ACCESS_ALLOWED  0
  37 #define ACCESS_DENIED   1
  38
  39 #define SIDOWNER 1
  40 #define SIDGROUP 2
  41
  42 /*
  43  * Security Descriptor length containing DACL with 3 ACEs (one each for
  44  * owner, group and world).
  45  */
  46 #define DEFAULT_SEC_DESC_LEN (sizeof(struct cifs_ntsd) + \
  47                               sizeof(struct cifs_acl) + \
  48                               (sizeof(struct cifs_ace) * 3))
  49
  50 /*
  51  * Maximum size of a string representation of a SID:
  52  *
  53  * The fields are unsigned values in decimal. So:
  54  *
  55  * u8:  max 3 bytes in decimal
  56  * u32: max 10 bytes in decimal
  57  *
  58  * "S-" + 3 bytes for version field + 15 for authority field + NULL terminator
  59  *
  60  * For authority field, max is when all 6 values are non-zero and it must be
  61  * represented in hex. So "-0x" + 12 hex digits.
  62  *
  63  * Add 11 bytes for each subauthority field (10 bytes each + 1 for '-')
  64  */
  65 #define SID_STRING_BASE_SIZE (2 + 3 + 15 + 1)
  66 #define SID_STRING_SUBAUTH_SIZE (11) /* size of a single subauth string */
  67
  68 struct cifs_ntsd {
  69         __le16 revision; /* revision level */
  70         __le16 type;
  71         __le32 osidoffset;
  72         __le32 gsidoffset;
  73         __le32 sacloffset;
  74         __le32 dacloffset;
  75 } __attribute__((packed));
  76
  77 struct cifs_sid {
  78         __u8 revision; /* revision level */
  79         __u8 num_subauth;
  80         __u8 authority[NUM_AUTHS];
  81         __le32 sub_auth[SID_MAX_SUB_AUTHORITIES]; /* sub_auth[num_subauth] */
  82 } __attribute__((packed));
  83
  84 /* size of a struct cifs_sid, sans sub_auth array */
  85 #define CIFS_SID_BASE_SIZE (1 + 1 + NUM_AUTHS)
  86
  87 struct cifs_acl {
  88         __le16 revision; /* revision level */
  89         __le16 size;
  90         __le32 num_aces;
  91 } __attribute__((packed));
  92
  93 struct cifs_ace {
  94         __u8 type;
  95         __u8 flags;
  96         __le16 size;
  97         __le32 access_req;
  98         struct cifs_sid sid; /* ie UUID of user or group who gets these perms */
  99 } __attribute__((packed));
 100
 101 /*
 102  * Minimum security identifier can be one for system defined Users
 103  * and Groups such as NULL SID and World or Built-in accounts such
 104  * as Administrator and Guest and consists of
 105  * Revision + Num (Sub)Auths + Authority + Domain (one Subauthority)
 106  */
 107 #define MIN_SID_LEN  (1 + 1 + 6 + 4) /* in bytes */
 108
 109 /*
 110  * Minimum security descriptor can be one without any SACL and DACL and can
 111  * consist of revision, type, and two sids of minimum size for owner and group
 112  */
 113 #define MIN_SEC_DESC_LEN  (sizeof(struct cifs_ntsd) + (2 * MIN_SID_LEN))
 114
 115 #endif /* _CIFSACL_H */