# Source code for smb.security_descriptors

    """
    This module implements security descriptors, and the partial structures
    used in them, as specified in [MS-DTYP].
    """

    import struct

    # Security descriptor control flags
    # [MS-DTYP]: 2.4.6
    SECURITY_DESCRIPTOR_OWNER_DEFAULTED = 0x0001
    SECURITY_DESCRIPTOR_GROUP_DEFAULTED = 0x0002
    SECURITY_DESCRIPTOR_DACL_PRESENT = 0x0004
    SECURITY_DESCRIPTOR_DACL_DEFAULTED = 0x0008
    SECURITY_DESCRIPTOR_SACL_PRESENT = 0x0010
    SECURITY_DESCRIPTOR_SACL_DEFAULTED = 0x0020
    SECURITY_DESCRIPTOR_SERVER_SECURITY = 0x0040
    SECURITY_DESCRIPTOR_DACL_TRUSTED = 0x0080
    SECURITY_DESCRIPTOR_DACL_COMPUTED_INHERITANCE_REQUIRED = 0x0100
    SECURITY_DESCRIPTOR_SACL_COMPUTED_INHERITANCE_REQUIRED = 0x0200
    SECURITY_DESCRIPTOR_DACL_AUTO_INHERITED = 0x0400
    SECURITY_DESCRIPTOR_SACL_AUTO_INHERITED = 0x0800
    SECURITY_DESCRIPTOR_DACL_PROTECTED = 0x1000
    SECURITY_DESCRIPTOR_SACL_PROTECTED = 0x2000
    SECURITY_DESCRIPTOR_RM_CONTROL_VALID = 0x4000
    SECURITY_DESCRIPTOR_SELF_RELATIVE = 0x8000

    # ACE types
    # [MS-DTYP]: 2.4.4.1
    ACE_TYPE_ACCESS_ALLOWED = 0x00
    ACE_TYPE_ACCESS_DENIED = 0x01
    ACE_TYPE_SYSTEM_AUDIT = 0x02
    ACE_TYPE_SYSTEM_ALARM = 0x03
    ACE_TYPE_ACCESS_ALLOWED_COMPOUND = 0x04
    ACE_TYPE_ACCESS_ALLOWED_OBJECT = 0x05
    ACE_TYPE_ACCESS_DENIED_OBJECT = 0x06
    ACE_TYPE_SYSTEM_AUDIT_OBJECT = 0x07
    ACE_TYPE_SYSTEM_ALARM_OBJECT = 0x08
    ACE_TYPE_ACCESS_ALLOWED_CALLBACK = 0x09
    ACE_TYPE_ACCESS_DENIED_CALLBACK = 0x0A
    ACE_TYPE_ACCESS_ALLOWED_CALLBACK_OBJECT = 0x0B
    ACE_TYPE_ACCESS_DENIED_CALLBACK_OBJECT = 0x0C
    ACE_TYPE_SYSTEM_AUDIT_CALLBACK = 0x0D
    ACE_TYPE_SYSTEM_ALARM_CALLBACK = 0x0E
    ACE_TYPE_SYSTEM_AUDIT_CALLBACK_OBJECT = 0x0F
    ACE_TYPE_SYSTEM_ALARM_CALLBACK_OBJECT = 0x10
    ACE_TYPE_SYSTEM_MANDATORY_LABEL = 0x11
    ACE_TYPE_SYSTEM_RESOURCE_ATTRIBUTE = 0x12
    ACE_TYPE_SYSTEM_SCOPED_POLICY_ID = 0x13

    # ACE flags
    # [MS-DTYP]: 2.4.4.1
    ACE_FLAG_OBJECT_INHERIT = 0x01
    ACE_FLAG_CONTAINER_INHERIT = 0x02
    ACE_FLAG_NO_PROPAGATE_INHERIT = 0x04
    ACE_FLAG_INHERIT_ONLY = 0x08
    ACE_FLAG_INHERITED = 0x10
    ACE_FLAG_SUCCESSFUL_ACCESS = 0x40
    ACE_FLAG_FAILED_ACCESS = 0x80

    # Pre-defined well-known SIDs
    # [MS-DTYP]: 2.4.2.4
    SID_NULL = "S-1-0-0"
    SID_EVERYONE = "S-1-1-0"
    SID_LOCAL = "S-1-2-0"
    SID_CONSOLE_LOGON = "S-1-2-1"
    SID_CREATOR_OWNER = "S-1-3-0"
    SID_CREATOR_GROUP = "S-1-3-1"
    SID_OWNER_SERVER = "S-1-3-2"
    SID_GROUP_SERVER = "S-1-3-3"
    SID_OWNER_RIGHTS = "S-1-3-4"
    SID_NT_AUTHORITY = "S-1-5"
    SID_DIALUP = "S-1-5-1"
    SID_NETWORK = "S-1-5-2"
    SID_BATCH = "S-1-5-3"
    SID_INTERACTIVE = "S-1-5-4"
    SID_SERVICE = "S-1-5-6"
    SID_ANONYMOUS = "S-1-5-7"
    SID_PROXY = "S-1-5-8"
    SID_ENTERPRISE_DOMAIN_CONTROLLERS = "S-1-5-9"
    SID_PRINCIPAL_SELF = "S-1-5-10"
    SID_AUTHENTICATED_USERS = "S-1-5-11"
    SID_RESTRICTED_CODE = "S-1-5-12"
    SID_TERMINAL_SERVER_USER = "S-1-5-13"
    SID_REMOTE_INTERACTIVE_LOGON = "S-1-5-14"
    SID_THIS_ORGANIZATION = "S-1-5-15"
    SID_IUSR = "S-1-5-17"
    SID_LOCAL_SYSTEM = "S-1-5-18"
    SID_LOCAL_SERVICE = "S-1-5-19"
    SID_NETWORK_SERVICE = "S-1-5-20"
    SID_COMPOUNDED_AUTHENTICATION = "S-1-5-21-0-0-0-496"
    SID_CLAIMS_VALID = "S-1-5-21-0-0-0-497"
    SID_BUILTIN_ADMINISTRATORS = "S-1-5-32-544"
    SID_BUILTIN_USERS = "S-1-5-32-545"
    SID_BUILTIN_GUESTS = "S-1-5-32-546"
    SID_POWER_USERS = "S-1-5-32-547"
    SID_ACCOUNT_OPERATORS = "S-1-5-32-548"
    SID_SERVER_OPERATORS = "S-1-5-32-549"
    SID_PRINTER_OPERATORS = "S-1-5-32-550"
    SID_BACKUP_OPERATORS = "S-1-5-32-551"
    SID_REPLICATOR = "S-1-5-32-552"
    SID_ALIAS_PREW2KCOMPACC = "S-1-5-32-554"
    SID_REMOTE_DESKTOP = "S-1-5-32-555"
    SID_NETWORK_CONFIGURATION_OPS = "S-1-5-32-556"
    SID_INCOMING_FOREST_TRUST_BUILDERS = "S-1-5-32-557"
    SID_PERFMON_USERS = "S-1-5-32-558"
    SID_PERFLOG_USERS = "S-1-5-32-559"
    SID_WINDOWS_AUTHORIZATION_ACCESS_GROUP = "S-1-5-32-560"
    SID_TERMINAL_SERVER_LICENSE_SERVERS = "S-1-5-32-561"
    SID_DISTRIBUTED_COM_USERS = "S-1-5-32-562"
    SID_IIS_IUSRS = "S-1-5-32-568"
    SID_CRYPTOGRAPHIC_OPERATORS = "S-1-5-32-569"
    SID_EVENT_LOG_READERS = "S-1-5-32-573"
    SID_CERTIFICATE_SERVICE_DCOM_ACCESS = "S-1-5-32-574"
    SID_RDS_REMOTE_ACCESS_SERVERS = "S-1-5-32-575"
    SID_RDS_ENDPOINT_SERVERS = "S-1-5-32-576"
    SID_RDS_MANAGEMENT_SERVERS = "S-1-5-32-577"
    SID_HYPER_V_ADMINS = "S-1-5-32-578"
    SID_ACCESS_CONTROL_ASSISTANCE_OPS = "S-1-5-32-579"
    SID_REMOTE_MANAGEMENT_USERS = "S-1-5-32-580"
    SID_WRITE_RESTRICTED_CODE = "S-1-5-33"
    SID_NTLM_AUTHENTICATION = "S-1-5-64-10"
    SID_SCHANNEL_AUTHENTICATION = "S-1-5-64-14"
    SID_DIGEST_AUTHENTICATION = "S-1-5-64-21"
    SID_THIS_ORGANIZATION_CERTIFICATE = "S-1-5-65-1"
    SID_NT_SERVICE = "S-1-5-80"
    SID_USER_MODE_DRIVERS = "S-1-5-84-0-0-0-0-0"
    SID_LOCAL_ACCOUNT = "S-1-5-113"
    SID_LOCAL_ACCOUNT_AND_MEMBER_OF_ADMINISTRATORS_GROUP = "S-1-5-114"
    SID_OTHER_ORGANIZATION = "S-1-5-1000"
    SID_ALL_APP_PACKAGES = "S-1-15-2-1"
    SID_ML_UNTRUSTED = "S-1-16-0"
    SID_ML_LOW = "S-1-16-4096"
    SID_ML_MEDIUM = "S-1-16-8192"
    SID_ML_MEDIUM_PLUS = "S-1-16-8448"
    SID_ML_HIGH = "S-1-16-12288"
    SID_ML_SYSTEM = "S-1-16-16384"
    SID_ML_PROTECTED_PROCESS = "S-1-16-20480"
    SID_AUTHENTICATION_AUTHORITY_ASSERTED_IDENTITY = "S-1-18-1"
    SID_SERVICE_ASSERTED_IDENTITY = "S-1-18-2"
    SID_FRESH_PUBLIC_KEY_IDENTITY = "S-1-18-3"
    SID_KEY_TRUST_IDENTITY = "S-1-18-4"
    SID_KEY_PROPERTY_MFA = "S-1-18-5"
    SID_KEY_PROPERTY_ATTESTATION = "S-1-18-6"

    class SID(object):
        """
        A Windows security identifier. Represents a single principal, such a
        user or a group, as a sequence of numbers consisting of the revision,
        identifier authority, and a variable-length list of subauthorities.

        See [MS-DTYP]: 2.4.2
        """
        def __init__(self, revision, identifier_authority, subauthorities):
            #: Revision, should always be 1.
            self.revision = revision
            #: An integer representing the identifier authority.
            self.identifier_authority = identifier_authority
            #: A list of integers representing all subauthorities.
            self.subauthorities = subauthorities

        def __str__(self):
            """
            String representation, as specified in [MS-DTYP]: 2.4.2.1
            """
            if self.identifier_authority >= 2**32:
                id_auth = '%#x' % (self.identifier_authority,)
            else:
                id_auth = self.identifier_authority
            auths = [self.revision, id_auth] + self.subauthorities
            return 'S-' + '-'.join(str(subauth) for subauth in auths)

        def __repr__(self):
            return 'SID(%r)' % (str(self),)

        @classmethod
        def from_bytes(cls, data, return_tail=False):
            revision, subauth_count = struct.unpack('<BB', data[:2])
            identifier_authority = struct.unpack('>Q', '\x00\x00' + data[2:8])[0]
            subauth_data = data[8:]
            subauthorities = [struct.unpack('<L', subauth_data[4 * i : 4 * (i+1)])[0]
                              for i in range(subauth_count)]
            sid = cls(revision, identifier_authority, subauthorities)
            if return_tail:
                return sid, subauth_data[4 * subauth_count :]
            return sid

    class ACE(object):
        """
        Represents a single access control entry.

        See [MS-DTYP]: 2.4.4
        """
        HEADER_FORMAT = '<BBH'

        def __init__(self, type_, flags, mask, sid, additional_data):
            #: An integer representing the type of the ACE. One of the
            #: ``ACE_TYPE_*`` constants. Corresponds to the ``AceType`` field
            #: from [MS-DTYP] 2.4.4.1.
            self.type = type_
            #: An integer bitmask with ACE flags, corresponds to the
            #: ``AceFlags`` field.
            self.flags = flags
            #: An integer representing the ``ACCESS_MASK`` as specified in
            #: [MS-DTYP] 2.4.3.
            self.mask = mask
            #: The :class:`SID` of a trustee.
            self.sid = sid
            #: A dictionary of additional fields present in the ACE, depending
            #: on the type. The following fields can be present:
            #:
            #: * ``flags``
            #: * ``object_type``
            #: * ``inherited_object_type``
            #: * ``application_data``
            #: * ``attribute_data``
            self.additional_data = additional_data

        def __repr__(self):
            return "ACE(type=%#04x, flags=%#04x, mask=%#010x, sid=%s)" % (
                self.type, self.flags, self.mask, self.sid,
            )

        @property
        def isInheritOnly(self):
            """Convenience property which indicates if this ACE is inherit
            only, meaning that it doesn't apply to the object itself."""
            return bool(self.flags & ACE_FLAG_INHERIT_ONLY)

        @classmethod
        def from_bytes(cls, data):
            header_size = struct.calcsize(cls.HEADER_FORMAT)
            header = data[:header_size]
            type_, flags, size = struct.unpack(cls.HEADER_FORMAT, header)

            assert len(data) >= size

            body = data[header_size:size]
            additional_data = {}

            # In all ACE types, the mask immediately follows the header.
            mask = struct.unpack('<I', body[:4])[0]
            body = body[4:]

            # All OBJECT-type ACEs contain additional flags, and two GUIDs as
            # the following fields.
            if type_ in (ACE_TYPE_ACCESS_ALLOWED_OBJECT,
                         ACE_TYPE_ACCESS_DENIED_OBJECT,
                         ACE_TYPE_ACCESS_ALLOWED_CALLBACK_OBJECT,
                         ACE_TYPE_ACCESS_DENIED_CALLBACK_OBJECT,
                         ACE_TYPE_SYSTEM_AUDIT_OBJECT,
                         ACE_TYPE_SYSTEM_AUDIT_CALLBACK_OBJECT):
                additional_data['flags'] = struct.unpack('<I', body[:4])[0]
                additional_data['object_type'] = body[4:20]
                additional_data['inherited_object_type'] = body[20:36]
                body = body[36:]

            # Then the SID in all types.
            sid, body = SID.from_bytes(body, return_tail=True)

            # CALLBACK-type ACEs (and for some obscure reason,
            # SYSTEM_AUDIT_OBJECT) have a final tail of application data.
            if type_ in (ACE_TYPE_ACCESS_ALLOWED_CALLBACK,
                         ACE_TYPE_ACCESS_DENIED_CALLBACK,
                         ACE_TYPE_ACCESS_ALLOWED_CALLBACK_OBJECT,
                         ACE_TYPE_ACCESS_DENIED_CALLBACK_OBJECT,
                         ACE_TYPE_SYSTEM_AUDIT_OBJECT,
                         ACE_TYPE_SYSTEM_AUDIT_CALLBACK,
                         ACE_TYPE_SYSTEM_AUDIT_CALLBACK_OBJECT):
                additional_data['application_data'] = body

            # SYSTEM_RESOURCE_ATTRIBUTE ACEs have a tail of attribute data.
            if type_ == ACE_TYPE_SYSTEM_RESOURCE_ATTRIBUTE:
                additional_data['attribute_data'] = body

            return cls(type_, flags, mask, sid, additional_data)

    class ACL(object):
        """
        Access control list, encapsulating a sequence of access control
        entries.

        See [MS-DTYP]: 2.4.5
        """
        HEADER_FORMAT = '<BBHHH'

        def __init__(self, revision, aces):
            #: Integer value of the revision.
            self.revision = revision
            #: List of :class:`ACE` instances.
            self.aces = aces

        def __repr__(self):
            return "ACL(%r)" % (self.aces,)

        @classmethod
        def from_bytes(cls, data):
            revision = None
            aces = []

            header_size = struct.calcsize(cls.HEADER_FORMAT)
            header, remaining = data[:header_size], data[header_size:]
            revision, sbz1, size, count, sbz2 = struct.unpack(cls.HEADER_FORMAT, header)

            assert len(data) >= size

            for i in range(count):
                ace_size = struct.unpack('<H', remaining[2:4])[0]
                ace_data, remaining = remaining[:ace_size], remaining[ace_size:]
                aces.append(ACE.from_bytes(ace_data))

            return cls(revision, aces)

    class SecurityDescriptor(object):
        """
        Represents a security descriptor.

        See [MS-DTYP]: 2.4.6
        """

        HEADER_FORMAT = '<BBHIIII'

        def __init__(self, flags, owner, group, dacl, sacl):
            #: Integer bitmask of control flags. Corresponds to the
            #: ``Control`` field in [MS-DTYP] 2.4.6.
            self.flags = flags
            #: Instance of :class:`SID` representing the owner user.
            self.owner = owner
            #: Instance of :class:`SID` representing the owner group.
            self.group = group
            #: Instance of :class:`ACL` representing the discretionary access
            #: control list, which specifies access restrictions of an object.
            self.dacl = dacl
            #: Instance of :class:`ACL` representing the system access control
            #: list, which specifies audit logging of an object.
            self.sacl = sacl

        @classmethod
        def from_bytes(cls, data):
            owner = None
            group = None
            dacl = None
            sacl = None

            header = data[:struct.calcsize(cls.HEADER_FORMAT)]
            (revision, sbz1, flags, owner_offset, group_offset, sacl_offset,
             dacl_offset) = struct.unpack(cls.HEADER_FORMAT, header)

            assert revision == 1
            assert flags & SECURITY_DESCRIPTOR_SELF_RELATIVE
            for offset in (owner_offset, group_offset, sacl_offset, dacl_offset):
                assert 0 <= offset < len(data)

            if owner_offset:
                owner = SID.from_bytes(data[owner_offset:])
            if group_offset:
                group = SID.from_bytes(data[group_offset:])
            if dacl_offset:
                dacl = ACL.from_bytes(data[dacl_offset:])
            if sacl_offset:
                sacl = ACL.from_bytes(data[sacl_offset:])

            return cls(flags, owner, group, dacl, sacl)