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linux-next/fs/cifs/cifsacl.h
Shirish Pargaonkar ee25c6dd7b cifs: For SMB2 security informaion query, check for minimum sized security descriptor instead of sizeof FileAllInformation class
Validate_buf () function checks for an expected minimum sized response
passed to query_info() function.
For security information, the size of a security descriptor can be
smaller (one subauthority, no ACEs) than the size of the structure
that defines FileInfoClass of FileAllInformation.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199725
Cc: <stable@vger.kernel.org>
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Reviewed-by: Noah Morrison <noah.morrison@rubrik.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2018-06-04 19:19:24 -05:00

116 lines
3.4 KiB
C

/*
* 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 */