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>
This commit is contained in:
Shirish Pargaonkar 2018-06-04 06:46:22 -05:00 committed by Steve French
parent 57f933ce9f
commit ee25c6dd7b
2 changed files with 15 additions and 2 deletions

View File

@ -98,4 +98,18 @@ struct cifs_ace {
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 */

View File

@ -2492,8 +2492,7 @@ SMB2_query_acl(const unsigned int xid, struct cifs_tcon *tcon,
return query_info(xid, tcon, persistent_fid, volatile_fid,
0, SMB2_O_INFO_SECURITY, additional_info,
SMB2_MAX_BUFFER_SIZE,
sizeof(struct smb2_file_all_info), data, plen);
SMB2_MAX_BUFFER_SIZE, MIN_SEC_DESC_LEN, data, plen);
}
int