asn1rt: fix and ease the handling of OPEN internal object when using BER
This commit is contained in:
mitshell
parent
89a44358fb
commit
f98b911100
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@ -101,15 +101,14 @@ Alternative single value: Python 2-tuple
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def _get_val_obj(self, ref):
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if isinstance(ref, str_types):
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if ref in _ASN1ObjBasicLUT:
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const_tr = self._get_const_tr()
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if ref in const_tr:
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return const_tr[ref]
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elif ref in _ASN1ObjBasicLUT:
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return _ASN1ObjBasicLUT[ref]()
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else:
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const_tr = self._build_const_tr()
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try:
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return const_tr[ref]
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except:
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raise(ASN1ObjErr('{0}: invalid object reference, {1!r}'\
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.format(self.fullname(), ref)))
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raise(ASN1ObjErr('{0}: invalid object reference, {1!r}'\
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.format(self.fullname(), ref)))
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else:
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try:
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return GLOBAL.MOD[ref[0]][ref[1]]
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@ -192,8 +191,9 @@ Alternative single value: Python 2-tuple
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else:
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self._val = (Obj.TYPE, Obj._val)
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return txt
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raise(ASN1ASNDecodeErr('{0}: invalid text, {1!r}'\
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.format(self.fullname(), txt)))
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else:
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# TODO: module.object reference
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ASN1NotSuppErr('{0}: reference parsing unsupported'.format(self.fullname()))
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def _to_asn1(self):
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if isinstance(self._val, bytes_types):
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@ -203,18 +203,13 @@ Alternative single value: Python 2-tuple
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else:
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return '\'%s\'H' % hexlify(self._val).upper()
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else:
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if isinstance(self._val[0], tuple):
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ident = self._val[0][1]
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if isinstance(self._val[0], str_types):
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ident = self._val[0]
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else:
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ident = self._val[0]._name
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const_tr = self._build_const_tr()
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if ident in const_tr:
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Obj = const_tr[ident]
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Obj._val = self._val[1]
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return '%s: %s' % (ident, Obj.to_asn1())
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#Obj._val = None
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raise(ASN1ASNEncodeErr('{0}: non-encodable value, {1!r}'\
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.format(self.fullname(), self._val)))
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ident = '.'.join(self._val[0])
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Obj = self._get_val_obj(self._val[0])
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Obj._val = self._val[1]
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return '%s: %s' % (ident, Obj.to_asn1())
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###
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# conversion between internal value and ASN.1 PER encoding
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@ -247,7 +242,7 @@ Alternative single value: Python 2-tuple
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else:
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if Obj._typeref is not None:
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val, GEN = ASN1CodecPER.decode_unconst_open_ws(char, wrapped=Obj._tr)
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self._val = (Obj._typeref.called, val)
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self._val = (Obj._typeref.called[1], val)
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else:
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val, GEN = ASN1CodecPER.decode_unconst_open_ws(char, wrapped=Obj)
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self._val = (Obj.TYPE, val)
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@ -280,7 +275,7 @@ Alternative single value: Python 2-tuple
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self._val = val
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else:
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if Obj._typeref is not None:
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self._val = (Obj._typeref.called, val)
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self._val = (Obj._typeref.called[1], val)
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else:
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self._val = (Obj.TYPE, val)
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return
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@ -324,29 +319,49 @@ Alternative single value: Python 2-tuple
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# select the inner encoding
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tlv = tlv[0]
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Tag, cl, pc, tval, Len, lval = tlv[0:6]
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tag, Obj = (cl, tval), None
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# try to get a defined object from a table constraint
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if self._TAB_LUT and self._const_tab and self._const_tab_at:
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try:
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Obj = self._get_tab_obj()
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except Exception as err:
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if not self._SILENT:
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asnlog('OPEN._decode_ber_cont_ws: %s, unable to retrieve a table-looked up object, %s'\
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% (self._name, err))
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Obj = None
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else:
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# TODO: another way to provide a (set of) potential defined object(s)
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# is to look into value constraint self._const_val
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# if we have multiple, then we would have to bruteforce the decoding
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# until a correct one is found !!!
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Obj = None
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asnlog('OPEN._decode_ber_cont_ws: %s, unable to retrieve an object in the table '\
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'constraint, err %s' % (self.fullname(), err))
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#
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if Obj is None or (cl, tval) != Obj._tagc[0]:
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if self._const_val:
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asnlog('OPEN._decode_ber_cont_ws: %s, potential type constraint(s) available'\
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% self._name)
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elif hasattr(self, '_defby') and self._defby is not None:
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asnlog('ANY._decode_ber_cont_ws: %s, DEFINED BY construction unhandled'\
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% self._name)
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elif self._const_val is not None:
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# another way to provide a (set of) potential defined object(s)
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# is to look into value constraint self._const_val
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# we must select the right one according to the decoded tag
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Obj = get_obj_by_tag(self, tag)
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#
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elif hasattr(self, '_defby') and self._defby is not None:
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# TODO: 3rd way to specify the potential defined object
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# is to use a DEFINED BY specification (this is old-school)
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if not self._SILENT:
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asnlog('OPEN._decode_ber_cont_ws: %s, DEFINED BY lookup not supported' % self.fullname())
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#
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decoded = False
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if Obj is not None:
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# we found a defined object
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try:
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Obj._from_ber_ws(char, [tlv])
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except Exception as err:
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# decoding failed, we fall back to the simple buffer decoding
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asnlog('OPEN._decode_ber_cont_ws: %s, decoding failed for the selected object %s'\
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% (self.fullname(), Obj._name))
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else:
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# set value
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if Obj._typeref is not None:
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self._val = (Obj._typeref.called[1], Obj._val)
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else:
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self._val = (Obj.TYPE, Obj._val)
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V = Obj._struct
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decoded = True
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#
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if not decoded:
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# we did not find a defined object, or failed to decode it
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# hence we decode this as a simple buffer
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# with BER, we need to absolutely keep track of the decoded tag if
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# we want to be able to re-encode it
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self._val_tag = (cl, pc, tval)
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@ -375,52 +390,62 @@ Alternative single value: Python 2-tuple
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# select the inner encoding
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tlv = tlv[0]
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cl, pc, tval, lval = tlv[0:4]
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tag, Obj = (cl, tval), None
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# try to get a defined object from a table constraint
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if self._TAB_LUT and self._const_tab and self._const_tab_at:
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try:
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Obj = self._get_tab_obj()
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except Exception as err:
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if not self._SILENT:
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asnlog('OPEN._decode_ber_cont_ws: %s, unable to retrieve a table-looked up object, %s'\
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% (self._name, err))
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Obj = None
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else:
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# TODO: another way to provide a (set of) potential defined object(s)
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# is to look into value constraint self._const_val
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# if we have multiple, then we would have to bruteforce the decoding
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# until a correct one is found !!!
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Obj = None
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asnlog('OPEN._decode_ber_cont: %s, unable to retrieve an object in the table '\
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'constraint (%s)' % (self.fullname(), err))
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#
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if Obj is None or (cl, tval) != Obj._tagc[0]:
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if self._const_val:
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asnlog('OPEN._decode_ber_cont: %s, potential type constraint(s) available'\
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% self._name)
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elif hasattr(self, '_defby') and self._defby is not None:
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asnlog('ANY._decode_ber_cont: %s, DEFINED BY construction unhandled'\
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% self._name)
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elif self._const_val is not None:
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# another way to provide a (set of) potential defined object(s)
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# is to look into value constraint self._const_val
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# we must select the right one according to the decoded tag
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Obj = get_obj_by_tag(self, tag)
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#
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elif hasattr(self, '_defby') and self._defby is not None:
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# TODO: 3rd way to specify the potential defined object
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# is to use a DEFINED BY specification (this is old-school)
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if not self._SILENT:
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asnlog('OPEN._decode_ber_cont: %s, DEFINED BY lookup not supported' % self.fullname())
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#
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decoded = False
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if Obj is not None:
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# we found a defined object
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try:
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Obj._from_ber(char, [tlv])
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except Exception as err:
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# decoding failed, we fall back to the simple buffer decoding
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if not self._SILENT:
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asnlog('OPEN._decode_ber_cont: %s, decoding failed for the selected object %s'\
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% (self.fullname(), Obj._name))
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else:
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# set value
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if Obj._typeref is not None:
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self._val = (Obj._typeref.called[1], Obj._val)
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else:
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self._val = (Obj.TYPE, Obj._val)
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decoded = True
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#
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if not decoded:
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# we did not find a defined object, or failed to decode it
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# hence we decode this as a simple buffer
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# with BER, we need to absolutely keep track of the decoded tag if
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# we want to be able to re-encode it
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# hence we use the 10 first bytes to store the tag class, pc and value
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self._val_tag = (cl, pc, tval)
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if pc == 1:
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# constructed object
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val = ASN1CodecBER.scan_tlv_ws(char, tlv)
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self._val = ASN1CodecBER.scan_tlv_ws(char, tlv)
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elif lval >= 0:
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# primitive object
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char._cur = tlv[6][0]
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val = char.get_bytes(8*lval)
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char._cur, char._len_bit = tlv[4][0], tlv[4][1]
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self._val = char.get_bytes(8*lval)
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else:
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raise(ASN1BERDecodeErr('{0}: invalid OPEN / ANY tag and length, {1!r}, {2!r}'\
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.format(self.fullname(), (cl, pc, tval), lval)))
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# grilling t-bones on it
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self._val = pack('>BBQ', cl, pc, tval) + val
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else:
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# defined object
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Obj._from_ber(char, [tlv])
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# set value
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if Obj._typeref is not None:
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self._val = (Obj._typeref.called, Obj._val)
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else:
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self._val = (Obj.TYPE, Obj._val)
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def _encode_ber_cont_ws(self):
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if isinstance(self._val, bytes_types):
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