X-Git-Url: http://www.git.cypherpunks.ru/?a=blobdiff_plain;f=pyderasn.py;h=32d942460436403c3bde2725f92aa370e63e715f;hb=0265e9da3f3d6a84b79a231a7af0f694c7c96538;hp=887f000d20b73afbee0a348af9b2ad3681a79433;hpb=29a10ee9f33812d6ec56e1f59613853c14a63a78;p=pyderasn.git diff --git a/pyderasn.py b/pyderasn.py index 887f000..32d9424 100755 --- a/pyderasn.py +++ b/pyderasn.py @@ -1,12 +1,11 @@ #!/usr/bin/env python # coding: utf-8 # PyDERASN -- Python ASN.1 DER/BER codec with abstract structures -# Copyright (C) 2017-2019 Sergey Matveev +# Copyright (C) 2017-2020 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 -# published by the Free Software Foundation, either version 3 of the -# License, or (at your option) any later version. +# published by the Free Software Foundation, version 3 of the License. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of @@ -14,8 +13,7 @@ # GNU Lesser General Public License for more details. # # You should have received a copy of the GNU Lesser General Public -# License along with this program. If not, see -# . +# License along with this program. If not, see . """Python ASN.1 DER/BER codec with abstract structures This library allows you to marshal various structures in ASN.1 DER @@ -348,6 +346,8 @@ DEFINED BY some previously met ObjectIdentifier. This library provides ability to specify mapping between some OID and field that must be decoded with specific specification. +.. _defines: + defines kwarg _____________ @@ -421,15 +421,15 @@ value must be sequence of following tuples:: where ``decode_path`` is a tuple holding so-called decode path to the exact :py:class:`pyderasn.ObjectIdentifier` field you want to apply -``defines``, holding exactly the same value as accepted in its keyword -argument. +``defines``, holding exactly the same value as accepted in its +:ref:`keyword argument `. For example, again for CMS, you want to automatically decode ``SignedData`` and CMC's (:rfc:`5272`) ``PKIData`` and ``PKIResponse`` structures it may hold. Also, automatically decode ``controlSequence`` of ``PKIResponse``:: - content_info, tail = ContentInfo().decode(data, defines_by_path=( + content_info, tail = ContentInfo().decode(data, ctx={"defines_by_path": ( ( ("contentType",), ((("content",), {id_signedData: SignedData()}),), @@ -464,7 +464,7 @@ of ``PKIResponse``:: id_cmc_transactionId: TransactionId(), })), ), - )) + )}) Pay attention for :py:class:`pyderasn.DecodePathDefBy` and ``any``. First function is useful for path construction when some automatic @@ -517,6 +517,11 @@ lengths will be invalid in that case. This option should be used only for skipping some decode errors, just to see the decoded structure somehow. +Base Obj +-------- +.. autoclass:: pyderasn.Obj + :members: + Primitive types --------------- @@ -626,7 +631,6 @@ Various .. autofunction:: pyderasn.tag_decode .. autofunction:: pyderasn.tag_ctxp .. autofunction:: pyderasn.tag_ctxc -.. autoclass:: pyderasn.Obj .. autoclass:: pyderasn.DecodeError :members: __init__ .. autoclass:: pyderasn.NotEnoughData @@ -673,6 +677,7 @@ except ImportError: # pragma: no cover def colored(what, *args, **kwargs): return what +__version__ = "5.5" __all__ = ( "Any", @@ -1019,9 +1024,9 @@ def len_decode(data): ######################################################################## class AutoAddSlots(type): - def __new__(mcs, name, bases, _dict): + def __new__(cls, name, bases, _dict): _dict["__slots__"] = _dict.get("__slots__", ()) - return type.__new__(mcs, name, bases, _dict) + return type.__new__(cls, name, bases, _dict) @add_metaclass(AutoAddSlots) @@ -1095,10 +1100,14 @@ class Obj(object): @property def tlen(self): + """See :ref:`decoding` + """ return len(self.tag) @property def tlvlen(self): + """See :ref:`decoding` + """ return self.tlen + self.llen + self.vlen def __str__(self): # pragma: no cover @@ -1123,6 +1132,10 @@ class Obj(object): raise NotImplementedError() def encode(self): + """Encode the structure + + :returns: DER representation + """ raw = self._encode() if self._expl is None: return raw @@ -1150,6 +1163,8 @@ class Obj(object): determine if tag satisfies the scheme) :param _ctx_immutable: do we need to copy ``ctx`` before using it :returns: (Obj, remaining data) + + .. seealso:: :ref:`decoding` """ if ctx is None: ctx = {} @@ -1165,7 +1180,7 @@ class Obj(object): tag_only=tag_only, ) if tag_only: - return + return None obj, tail = result else: try: @@ -1203,7 +1218,7 @@ class Obj(object): tag_only=tag_only, ) if tag_only: # pragma: no cover - return + return None obj, tail = result eoc_expected, tail = tail[:EOC_LEN], tail[EOC_LEN:] if eoc_expected.tobytes() != EOC: @@ -1238,7 +1253,7 @@ class Obj(object): tag_only=tag_only, ) if tag_only: # pragma: no cover - return + return None obj, tail = result if obj.tlvlen < l and not ctx.get("allow_expl_oob", False): raise DecodeError( @@ -1251,40 +1266,58 @@ class Obj(object): @property def expled(self): + """See :ref:`decoding` + """ return self._expl is not None @property def expl_tag(self): + """See :ref:`decoding` + """ return self._expl @property def expl_tlen(self): + """See :ref:`decoding` + """ return len(self._expl) @property def expl_llen(self): + """See :ref:`decoding` + """ if self.expl_lenindef: return 1 return len(len_encode(self.tlvlen)) @property def expl_offset(self): + """See :ref:`decoding` + """ return self.offset - self.expl_tlen - self.expl_llen @property def expl_vlen(self): + """See :ref:`decoding` + """ return self.tlvlen @property def expl_tlvlen(self): + """See :ref:`decoding` + """ return self.expl_tlen + self.expl_llen + self.expl_vlen @property def fulloffset(self): + """See :ref:`decoding` + """ return self.expl_offset if self.expled else self.offset @property def fulllen(self): + """See :ref:`decoding` + """ return self.expl_tlvlen if self.expled else self.tlvlen def pps_lenindef(self, decode_path): @@ -1747,7 +1780,7 @@ class Boolean(Obj): offset=offset, ) if tag_only: - return + return None try: l, _, v = len_decode(lv) except DecodeError as err: @@ -1977,6 +2010,7 @@ class Integer(Obj): for name, value in iteritems(self.specs): if value == self._value: return name + return None def __call__( self, @@ -2056,7 +2090,7 @@ class Integer(Obj): offset=offset, ) if tag_only: - return + return None try: l, llen, v = len_decode(lv) except DecodeError as err: @@ -2474,7 +2508,7 @@ class BitString(Obj): ) if t == self.tag: if tag_only: # pragma: no cover - return + return None return self._decode_chunk(lv, offset, decode_path, ctx) if t == self.tag_constructed: if not ctx.get("bered", False): @@ -2485,7 +2519,7 @@ class BitString(Obj): offset=offset, ) if tag_only: # pragma: no cover - return + return None lenindef = False try: l, llen, v = len_decode(lv) @@ -2850,7 +2884,7 @@ class OctetString(Obj): ) if t == self.tag: if tag_only: - return + return None return self._decode_chunk(lv, offset, decode_path, ctx) if t == self.tag_constructed: if not ctx.get("bered", False): @@ -2861,7 +2895,7 @@ class OctetString(Obj): offset=offset, ) if tag_only: - return + return None lenindef = False try: l, llen, v = len_decode(lv) @@ -3077,7 +3111,7 @@ class Null(Obj): offset=offset, ) if tag_only: # pragma: no cover - return + return None try: l, _, v = len_decode(lv) except DecodeError as err: @@ -3332,7 +3366,7 @@ class ObjectIdentifier(Obj): offset=offset, ) if tag_only: # pragma: no cover - return + return None try: l, llen, v = len_decode(lv) except DecodeError as err: @@ -4250,7 +4284,7 @@ class Choice(Obj): offset=offset, ) if tag_only: # pragma: no cover - return + return None value, tail = spec.decode( tlv, offset=offset, @@ -4833,7 +4867,7 @@ class Sequence(Obj): offset=offset, ) if tag_only: # pragma: no cover - return + return None lenindef = False ctx_bered = ctx.get("bered", False) try: @@ -4885,8 +4919,8 @@ class Sequence(Obj): ctx=ctx, _ctx_immutable=False, ) - except TagMismatch: - if spec.optional: + except TagMismatch as err: + if (len(err.decode_path) == len(decode_path) + 1) and spec.optional: continue raise @@ -5083,7 +5117,7 @@ class Set(Sequence): offset=offset, ) if tag_only: - return + return None lenindef = False ctx_bered = ctx.get("bered", False) try: @@ -5416,7 +5450,7 @@ class SequenceOf(Obj): offset=offset, ) if tag_only: - return + return None lenindef = False ctx_bered = ctx.get("bered", False) try: