X-Git-Url: http://www.git.cypherpunks.ru/?p=pyderasn.git;a=blobdiff_plain;f=pyderasn.py;h=73eec5ead5d3fbd1558d45e2fa4e5d2ad17ec9ee;hp=56eec8d7953e62d6b63295b80795d1dd148d8aed;hb=b9b1e4187b0cd072dd1ccd1f34aa30232483d84d;hpb=7aed684a10179b2e57e81369e956ac6df4fb135e diff --git a/pyderasn.py b/pyderasn.py index 56eec8d..73eec5e 100755 --- a/pyderasn.py +++ b/pyderasn.py @@ -1,7 +1,7 @@ #!/usr/bin/env python # coding: utf-8 # PyDERASN -- Python ASN.1 DER codec with abstract structures -# Copyright (C) 2017 Sergey Matveev +# Copyright (C) 2017-2018 Sergey Matveev # # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU Lesser General Public License as @@ -68,7 +68,7 @@ ____ Most types in ASN.1 has specific tag for them. ``Obj.tag_default`` is the default tag used during coding process. You can override it with either ``IMPLICIT`` (using ``impl`` keyword argument), or -``EXPLICIT`` one (using ``expl`` keyword argument). Both arguments takes +``EXPLICIT`` one (using ``expl`` keyword argument). Both arguments take raw binary string, containing that tag. You can **not** set implicit and explicit tags simultaneously. @@ -88,10 +88,10 @@ number. Pay attention that explicit tags always have *constructed* tag Implicit tag is not explicitly shown. -Two object of the same type, but with different implicit/explicit tags +Two objects of the same type, but with different implicit/explicit tags are **not** equal. -You can get objects effective tag (either default or implicited) through +You can get object's effective tag (either default or implicited) through ``tag`` property. You can decode it using :py:func:`pyderasn.tag_decode` function:: @@ -159,12 +159,12 @@ raised. Common methods ______________ -All objects have ``ready`` boolean property, that tells if it is ready -to be encoded. If that kind of action is performed on unready object, -then :py:exc:`pyderasn.ObjNotReady` exception will be raised. +All objects have ``ready`` boolean property, that tells if object is +ready to be encoded. If that kind of action is performed on unready +object, then :py:exc:`pyderasn.ObjNotReady` exception will be raised. -All objects have ``copy()`` method, returning its copy, that can be safely -mutated. +All objects have ``copy()`` method, that returns their copy, that can be +safely mutated. .. _decoding: @@ -251,16 +251,19 @@ done. Following types can be automatically decoded (DEFINED BY): * :py:class:`pyderasn.Any` +* :py:class:`pyderasn.BitString` (that is multiple of 8 bits) * :py:class:`pyderasn.OctetString` * :py:class:`pyderasn.SequenceOf`/:py:class:`pyderasn.SetOf` ``Any``/``OctetString``-s When any of those fields is automatically decoded, then ``.defined`` -attribute contains ``(OID, value)`` tuple. OID tell by which OID it was -defined, ``value`` contains corresponding decoded value. For example +attribute contains ``(OID, value)`` tuple. ``OID`` tells by which OID it +was defined, ``value`` contains corresponding decoded value. For example above, ``content_info["content"].defined == (id_signedData, signed_data)``. +.. _defines_by_path_kwarg: + defines_by_path kwarg _____________________ @@ -322,8 +325,8 @@ of ``PKIResponse``:: Pay attention for :py:func:`pyderasn.decode_path_defby` and ``any``. First function is useful for path construction when some automatic -decoding is already done. ``any`` is used for human readability and -means literally any value it meet -- useful for sequence and set of-s. +decoding is already done. ``any`` means literally any value it meet -- +useful for SEQUENCE/SET OF-s. Primitive types --------------- @@ -774,9 +777,9 @@ def len_decode(data): ######################################################################## class AutoAddSlots(type): - def __new__(cls, name, bases, _dict): + def __new__(mcs, name, bases, _dict): _dict["__slots__"] = _dict.get("__slots__", ()) - return type.__new__(cls, name, bases, _dict) + return type.__new__(mcs, name, bases, _dict) @add_metaclass(AutoAddSlots) @@ -1679,7 +1682,7 @@ class BitString(Obj): >>> b.specs {'nonRepudiation': 1, 'digitalSignature': 0, 'keyEncipherment': 2} """ - __slots__ = ("specs",) + __slots__ = ("specs", "defined") tag_default = tag_encode(3) asn1_type_name = "BIT STRING" @@ -1716,6 +1719,7 @@ class BitString(Obj): ) if value is None: self._value = default + self.defined = None def _bits2octets(self, bits): if len(self.specs) > 0: @@ -1964,6 +1968,11 @@ class BitString(Obj): expl_llen=self.expl_llen if self.expled else None, expl_vlen=self.expl_vlen if self.expled else None, ) + defined_by, defined = self.defined or (None, None) + if defined_by is not None: + yield defined.pps( + decode_path=decode_path + (decode_path_defby(defined_by),) + ) class OctetString(Obj): @@ -4282,9 +4291,56 @@ def obj_by_path(pypath): # pragma: no cover return obj +def generic_decoder(): # pragma: no cover + # All of this below is a big hack with self references + choice = PrimitiveTypes() + choice.specs["SequenceOf"] = SequenceOf(schema=choice) + choice.specs["SetOf"] = SetOf(schema=choice) + for i in range(31): + choice.specs["SequenceOf%d" % i] = SequenceOf( + schema=choice, + expl=tag_ctxc(i), + ) + choice.specs["Any"] = Any() + + # Class name equals to type name, to omit it from output + class SEQUENCEOF(SequenceOf): + __slots__ = () + schema = choice + + def pprint_any(obj, oids=None): + def _pprint_pps(pps): + for pp in pps: + if hasattr(pp, "_fields"): + if pp.asn1_type_name == Choice.asn1_type_name: + continue + pp_kwargs = pp._asdict() + pp_kwargs["decode_path"] = pp.decode_path[:-1] + (">",) + pp = _pp(**pp_kwargs) + yield pp_console_row( + pp, + oids=oids, + with_offsets=True, + with_blob=False, + ) + for row in pp_console_blob(pp): + yield row + else: + for row in _pprint_pps(pp): + yield row + return "\n".join(_pprint_pps(obj.pps())) + return SEQUENCEOF(), pprint_any + + def main(): # pragma: no cover import argparse parser = argparse.ArgumentParser(description="PyDERASN ASN.1 DER decoder") + parser.add_argument( + "--skip", + type=int, + default=0, + help="Skip that number of bytes from the beginning", + ) parser.add_argument( "--oids", help="Python path to dictionary with OIDs", @@ -4293,12 +4349,17 @@ def main(): # pragma: no cover "--schema", help="Python path to schema definition to use", ) + parser.add_argument( + "--defines-by-path", + help="Python path to decoder's defines_by_path", + ) parser.add_argument( "DERFile", type=argparse.FileType("rb"), help="Path to DER file you want to decode", ) args = parser.parse_args() + args.DERFile.seek(args.skip) der = memoryview(args.DERFile.read()) args.DERFile.close() oids = obj_by_path(args.oids) if args.oids else {} @@ -4307,46 +4368,14 @@ def main(): # pragma: no cover from functools import partial pprinter = partial(pprint, big_blobs=True) else: - # All of this below is a big hack with self references - choice = PrimitiveTypes() - choice.specs["SequenceOf"] = SequenceOf(schema=choice) - choice.specs["SetOf"] = SetOf(schema=choice) - for i in range(31): - choice.specs["SequenceOf%d" % i] = SequenceOf( - schema=choice, - expl=tag_ctxc(i), - ) - choice.specs["Any"] = Any() - - # Class name equals to type name, to omit it from output - class SEQUENCEOF(SequenceOf): - __slots__ = () - schema = choice - schema = SEQUENCEOF() - - def pprint_any(obj, oids=None): - def _pprint_pps(pps): - for pp in pps: - if hasattr(pp, "_fields"): - if pp.asn1_type_name == Choice.asn1_type_name: - continue - pp_kwargs = pp._asdict() - pp_kwargs["decode_path"] = pp.decode_path[:-1] + (">",) - pp = _pp(**pp_kwargs) - yield pp_console_row( - pp, - oids=oids, - with_offsets=True, - with_blob=False, - ) - for row in pp_console_blob(pp): - yield row - else: - for row in _pprint_pps(pp): - yield row - return "\n".join(_pprint_pps(obj.pps())) - pprinter = pprint_any - obj, tail = schema().decode(der) + schema, pprinter = generic_decoder() + obj, tail = schema().decode( + der, + defines_by_path=( + None if args.defines_by_path is None + else obj_by_path(args.defines_by_path) + ), + ) print(pprinter(obj, oids=oids)) if tail != b"": print("\nTrailing data: %s" % hexenc(tail))