tty0
  	   ˆÂÁ0À¿  	   	ˆÂÁ0À¿  "   ˆl–äY>”*i?u ¸ ¸ \”Å£ÂƒqÇÃÁÀ #    """passlib.handlers.oracle - Oracle DB Password Hashes"""
#=============================================================================
# imports
#=============================================================================
# core
from binascii import hexlify, unhexlify
from hashlib import sha1
import re
import logging; log = logging.getLogger(__name__)
# site
# pkg
from passlib.utils import to_unicode, xor_bytes
from passlib.utils.compat import irange, u, \
                                 uascii_to_str, unicode, str_to_uascii
from passlib.crypto.des import des_encrypt_block
import passlib.utils.handlers as uh
# local
__all__ = [
    "oracle10g",
    "oracle11g"
]

#=============================================================================
# oracle10
#=============================================================================
def des_cbc_encrypt(key, value, iv=b'\x00' * 8, pad=b'\x00'):
    """performs des-cbc encryption, returns only last block.

    this performs a specific DES-CBC encryption implementation
    as needed by the Oracle10 hash. it probably won't be useful for
    other purposes as-is.

    input value is null-padded to multiple of 8 bytes.

    :arg key: des key as bytes
    :arg value: value to encrypt, as bytes.
    :param iv: optional IV
    :param pad: optional pad byte

    :returns: last block of DES-CBC encryption of all ``value``'s byte blocks.
    """
    value += pad * (-len(value) % 8) # null pad to multiple of 8
    hash = iv # start things off
    for offset in irange(0,len(value),8):
        chunk = xor_bytes(hash, value[offset:offset+8])
        hash = des_encrypt_block(key, chunk)
    return hash

# magic string used as initial des key by oracle10
ORACLE10_MAGIC = b"\x01\x23\x45\x67\x89\xAB\xCD\xEF"

class oracle10(uh.HasUserContext, uh.StaticHandler):
    """This class implements the password hash used by Oracle up to version 10g, and follows the :ref:`password-hash-api`.

    It does a single round of hashing, and relies on the username as the salt.

    The :meth:`~passlib.ifc.PasswordHash.hash`, :meth:`~passlib.ifc.PasswordHash.genhash`, and :meth:`~passlib.ifc.PasswordHash.verify` methods all require the
    following additional contextual keywords:

    :type user: str
    :param user: name of oracle user account this password is associated with.
    """
    #===================================================================
    # algorithm information
    #===================================================================
    name = "oracle10"
    checksum_chars = uh.HEX_CHARS
    checksum_size = 16

    #===================================================================
    # methods
    #===================================================================
    @classmethod
    def _norm_hash(cls, hash):
        return hash.upper()

    def _calc_checksum(self, secret):
        # FIXME: not sure how oracle handles unicode.
        #        online docs about 10g hash indicate it puts ascii chars
        #        in a 2-byte encoding w/ the high byte set to null.
        #        they don't say how it handles other chars, or what encoding.
        #
        #        so for now, encoding secret & user to utf-16-be,
        #        since that fits, and if secret/user is bytes,
        #        we assume utf-8, and decode first.
        #
        #        this whole mess really needs someone w/ an oracle system,
        #        and some answers :)
        if isinstance(secret, bytes):
            secret = secret.decode("utf-8")
        user = to_unicode(self.user, "utf-8", param="user")
        input = (user+secret).upper().encode("utf-16-be")
        hash = des_cbc_encrypt(ORACLE10_MAGIC, input)
        hash = des_cbc_encrypt(hash, input)
        return hexlify(hash).decode("ascii").upper()

    #===================================================================
    # eoc
    #===================================================================

#====================================