def der_pack(value, hint='no_hint', der_packer=None, cls=None):
"""Pack a Python value into a binary string holding a DER blob; see
der_format() for a version that does not include the DER header.
Since native types may have been produced from a variety of
ASN.1 types, the hint can be used to signal the type name
(though any STRING trailer is stripped). Alternatively,
use cls to provide an ASN1Object subclass for packing or
a der_packer instruction to apply. The latter could crash
if not properly formatted -- at least make sure its DER_ENTER_
and DER_LEAVE nest properly and that the der_packer ends in
DER_PACK_END.
"""
if der_packer is not None:
if not type(value) == list:
value = [value]
if cls is not None:
raise Exception('der_pack(...,der_packer=...,cls=...) is ambiguous')
if hint != 'no_hint':
raise Exception('der_pack(...,der_packer=...,hint=...) is ambiguous')
return _quickder.der_pack(der_packer, value)
elif cls is not None:
if not issubclass(cls, classes.ASN1Object):
raise Exception('der_pack(value,cls=...) requires cls to be a subclass of ASN1Object')
if not type(value) == list:
value = [value]
if hint != 'no_hint':
raise Exception('der_pack(...,cls=...,hint=...) is ambiguous')
return _quickder.der_pack(cls._der_packer, value)
elif isinstance(value, classes.ASN1Object):
return value._der_pack()
else:
(tag, packfun) = _der_hintmapping(type(value), hint)
return primitive.der_prefixhead(tag, packfun(value))
def der_format_OID(oidstr, hdr=False):
oidvals = list(map(int, oidstr.split('.')))
oidvals[1] += 40 * oidvals[0]
enc = ''
for oidx in range(len(oidvals) - 1, 0, -1):
oidval = oidvals[oidx]
enc = chr(oidval & 0x7f) + enc
while oidval > 127:
oidval >>= 7
enc = chr(0x80 | (oidval & 0x7f)) + enc
if hdr:
enc = _quickder.der_pack('\x06\x00', [enc])
return enc
def der_format_OID(oidstr, hdr=False):
oidvals = list(map(int, oidstr.split('.')))
oidvals[1] += 40 * oidvals[0]
enc = ''
for oidx in range(len(oidvals) - 1, 0, -1):
oidval = oidvals[oidx]
enc = chr(oidval & 0x7f) + enc
while oidval > 127:
oidval >>= 7
enc = chr(0x80 | (oidval & 0x7f)) + enc
if hdr:
enc = _quickder.der_pack('\x06\x00', [enc])
return enc
def der_format_INTEGER(ival, hdr=False):
retval = ''
byt = ival & 0xff
while ival not in [0, -1]:
ival = ival >> 8
retval = chr(byt) + retval
if ival == 0:
if len(retval) > 0 and byt & 0x80 == 0x80:
retval = chr(0x00) + retval
else:
if len(retval) == 0 or byt & 0x80 == 0x00:
retval = chr(0xff) + retval
if hdr:
retval = _quickder.der_pack('\x02\x00', [retval])
return retval
def der_format_INTEGER(ival, hdr=False):
retval = ''
byt = ival & 0xff
while ival not in [0, -1]:
byt = ival & 0xff
ival = ival >> 8
retval = chr(byt) + retval
if ival == 0:
if len(retval) > 0 and byt & 0x80 == 0x80:
retval = chr(0x00) + retval
else:
if len(retval) == 0 or byt & 0x80 == 0x00:
retval = chr(0xff) + retval
if hdr:
retval = _quickder.der_pack('\x02\x00', [retval])
return retval
def _der_pack(self):
"""Pack the current ASN1ConstructedType using DER notation.
Follow the syntax that was setup when this object
was created, usually after a der_unpack() operation
or a der_unpack(ClassName, derblob) or empty(ClassName)
call. Return the bytes with the packed data.
"""
bindata = []
for bd in self._bindata[self._offset:self._offset + self._numcursori]:
# TODO# set, list, atomic...
print('bindata[] element is a {}'.format(type(bd)))
if bd is not None and type(bd) != str:
# Hope to map the value to DER without hints
# TODO# Currently fails on ASN1Objects
bd = format.der_format(bd)
bindata.append(bd)
return _quickder.der_pack(self._der_packer, bindata)
def _der_pack(self):
"""Pack the current ASN1ConstructedType using DER notation.
Follow the syntax that was setup when this object
was created, usually after a der_unpack() operation
or a der_unpack(ClassName, derblob) or empty(ClassName)
call. Return the bytes with the packed data.
"""
bindata = []
for bd in self._bindata[self._offset:self._offset + self._numcursori]:
# TODO# set, list, atomic...
print('bindata[] element is a {}'.format(type(bd)))
if bd is not None and type(bd) != str:
# Hope to map the value to DER without hints
# TODO# Currently fails on ASN1Objects
from quick_der import format
bd = format.der_format(bd)
bindata.append(bd)
return _quickder.der_pack(self._der_packer, bindata)