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Diffstat (limited to 'pow/POW-0.7/lib/_der.py')
| -rw-r--r-- | pow/POW-0.7/lib/_der.py | 2294 |
1 files changed, 0 insertions, 2294 deletions
diff --git a/pow/POW-0.7/lib/_der.py b/pow/POW-0.7/lib/_der.py deleted file mode 100644 index c7f58411..00000000 --- a/pow/POW-0.7/lib/_der.py +++ /dev/null @@ -1,2294 +0,0 @@ -#*****************************************************************************# -#* *# -#* Copyright (c) 2002, Peter Shannon *# -#* All rights reserved. *# -#* *# -#* Redistribution and use in source and binary forms, with or without *# -#* modification, are permitted provided that the following conditions *# -#* are met: *# -#* *# -#* * Redistributions of source code must retain the above *# -#* copyright notice, this list of conditions and the following *# -#* disclaimer. *# -#* *# -#* * Redistributions in binary form must reproduce the above *# -#* copyright notice, this list of conditions and the following *# -#* disclaimer in the documentation and/or other materials *# -#* provided with the distribution. *# -#* *# -#* * The name of the contributors may be used to endorse or promote *# -#* products derived from this software without specific prior *# -#* written permission. *# -#* *# -#* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS *# -#* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT *# -#* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS *# -#* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS *# -#* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, *# -#* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT *# -#* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, *# -#* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY *# -#* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT *# -#* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE *# -#* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. *# -#* *# -#*****************************************************************************# - -import exceptions, types, copy, string, time, base64, traceback, cStringIO - -DEBUG = 0 - -# CLASS -CLASS_UNIVERSAL = 0x00 -CLASS_APPLICATION = 0x40 -CLASS_CONTEXT = 0x80 -CLASS_PRIVATE = 0xC0 - -# FORM -FORM_PRIMITIVE = 0x00 -FORM_CONSTRUCTED = 0x20 - -# TAG -TAG_BOOLEAN = 0x01 -TAG_INTEGER = 0x02 -TAG_BITSTRING = 0x03 -TAG_OCTETSTRING = 0x04 -TAG_NULL = 0x05 -TAG_OID = 0x06 -TAG_OBJDESCRIPTOR = 0x07 -TAG_EXTERNAL = 0x08 -TAG_REAL = 0x09 -TAG_ENUMERATED = 0x0A -TAG_EMBEDDED_PDV = 0x0B -TAG_UTF8STRING = 0x0C -TAG_SEQUENCE = 0x10 -TAG_SET = 0x11 -TAG_NUMERICSTRING = 0x12 -TAG_PRINTABLESTRING = 0x13 -TAG_T61STRING = 0x14 -TAG_VIDEOTEXSTRING = 0x15 -TAG_IA5STRING = 0x16 -TAG_UTCTIME = 0x17 -TAG_GENERALIZEDTIME = 0x18 -TAG_GRAPHICSTRING = 0x19 -TAG_VISIBLESTRING = 0x1A -TAG_GENERALSTRING = 0x1B -TAG_UNIVERSALSTRING = 0x1C -TAG_BMPSTRING = 0x1E - -_fragments = [] - -def _docset(): - return _fragments - -def _addFragment(frag): - global _fragments - _fragments.append(frag) - - -_addFragment(''' -<moduleDescription> - <header> - <name>POW.pkix</name> - <author>Peter Shannon</author> - </header> - <body> - <para> - This module is a solution to reading and writing X509v3 written - purely in Python. It does use limited facilities from POW for - signing and verifying but these could be replaced easily. It is - an abstract module and to use it successfully RFC3280 should be - referred to as well as the sourcecode where necessary. The correct - use of many extensions often not clear from the definitions alone. - Do refer to the RFC for details. - </para> - <para> - Each constructed objects defined in the RFC is built from primitives - defined by the ASN1 recommedations. Not all ASN1 primitive are available but all those - required for X509v3 should be. The implementation is more or less - complete for DER encoding the only caveat, aside from a few - missing objects, is the behaviour of <classname>SET</classname> objects - and <classname>SET OF</classname> objects. The order the objects are - written in should be determined at runtime by sorting their tags but this - library does not do this. For X509 it isn't really necessary - since all the <classname>Set</classname> objects are simple and the - order they are written in is defined by the object's constructor. - </para> - <para> - Every documented object in this module supports the functions documented for - <classname>_GeneralObject</classname>. In general the function - will only be documented in descendant classes if the class changes - the behaviour significantly from its ancestor. This would - normally be <classname>_GeneralObject</classname> or - <classname>Sequence</classname>. - </para> - </body> -</moduleDescription> -''') - -class DerError(Exception): - def __init__(self, msg): - if not isinstance(msg, types.StringType): - raise Exception, 'argunment should be a string' - self.msg = msg - - def __repr__(self): - return self.msg - - __str__ = __repr__ - -class _Tag(object): - def __init__(self): - self.tagclass = 0 - self.tagform = 0 - self.tagnumber = 0 - - def __repr__(self): - return '(%s, %s, %s)' % (self.tagclass, self.tagform, self.tagnumber) - - def write(self, file): - if self.tagnumber < 31: - file.write( chr(self.tagclass | self.tagform | self.tagnumber) ) - else: - val = copy.deepcopy(self.tagnumber) - bytes = [] - while val: - byte = val & 0x7F - bytes.append(byte | 0x80) - val = val >> 7 - bytes[0] = bytes[0] ^ 0x80 - bytes.append( self.tagclass | self.tagform | 0x1F ) - bytes.reverse() - file.write( string.join(map(chr, bytes), '') ) - - def read(self, file): - octet1 = ord( file.read(1) ) - self.tagclass = octet1 & 0xC0 - self.tagform = octet1 & 0x20 - value = octet1 & 0x1F - if value < 31: - self.tagnumber = value - else: - total = 0 - byte = 0x80 - while byte & 0x80: - byte = ord( file.read(1) ) - if byte & 0x80: - total = (total << 7) | byte ^ 0x80 - else: - total = (total << 7) | byte - self.tagnumber = total - -class _Length(object): - def __init__(self): - self.length = 0 - - def __repr__(self): - return '(%s)' % self.length - - def write(self, file): - if self.length < 128: - file.write( chr(self.length) ) - else: - val = copy.deepcopy(self.length) - bytes = [] - while val: - byte = val & 0xFF - bytes.append(byte) - val = val >> 8 - lengthOfLength = len(bytes) - if lengthOfLength > 126: - raise DerError, 'object is too long!' - bytes.append(lengthOfLength) - bytes.reverse() - bytes[0] = bytes[0] ^ 0x80 - file.write( string.join(map(chr, bytes), '') ) - - def read(self, file): - octet1 = ord( file.read(1) ) - if octet1 < 128: - self.length = octet1 - else: - total = 0 - byte = 0 - for i in range(octet1 ^ 0x80): - byte = ord( file.read(1) ) - total = (total << 8) | byte - self.length = total - -class _TlvIo(_Tag, _Length): - def __init__(self, file): - self.file = file - self.offset = None - self.valueOffset = None - - def __repr__(self): - return '<TAG:%s Length:%s>' % (_Tag.__repr__(self), _Length.__repr__(self)) - - def __nonzero__(self): - pos = self.file.tell() - self.file.seek(0,2) - if self.file.tell(): - self.file.seek(pos) - return 1 - else: - return 0 - - def read(self): - self.offset = self.file.tell() - _Tag.read( self, self.file ) - _Length.read( self, self.file ) - self.valueOffset = self.file.tell() - self.file.seek( self.length, 1 ) - - def readValue(self): - self.file.seek( self.valueOffset ) - return self.file.read( self.length ) - - def write(self, val): - _Tag.write( self, self.file ) - self.length = len(val) - _Length.write( self, self.file ) - self.file.write(val) - -def _decodeBoolean(val): - 'der encoded value not including tag or length' - if not isinstance(val, types.StringType): - raise DerError, 'argument should be a string' - if ord(val) == 0xFF: - return 1 - elif ord(val) == 0x00: - return 0 - else: - raise DerError, 'boolean should be encode as all 1s or all 0s' - -def _encodeBoolean(val): - 'anything we can test for truth' - if val: - return chr(0xFF) - else: - return chr(0x00) - -def _decodeInteger(val): - 'der encoded value not including tag or length' - if not isinstance(val, types.StringType): - raise DerError, 'argument should be a string' - total = 0L - if ord(val[0]) & 0x80: - val = map( lambda x : ord(x) ^ 0xFF, val ) - for byte in val: - total = (total << 8) | byte - total = -(total+1) - else: - for byte in val: - total = (total << 8) | ord(byte) - return total - -def _encodeInteger(val): - 'python integer' - if not isinstance(val, types.IntType) and not isinstance(val, types.LongType): - raise DerError, 'argument should be an integer' - if val == 0: - return chr(0x00) - else: - val2 = copy.deepcopy(val) - if val2 < 0: - val2 = -(val2+1) - bytes = [] - byte = 0 - while val2: - byte = val2 & 0xFF - bytes.append(byte) - val2 = val2 >> 8 - # if we have no used up the last byte to represent the value we need - # to add one more on to show if this is negative of positive. Also, - # due to adding 1 and inverting -1 would be 0 or if 0 is the encoding - # value, so bytes would empty and this would lead to and empty value - # and this would not be working properly. Adding this null byte - # fixes this, since it is inverted to -1 and preserved for 0. - if byte & 0x80 or not bytes: - bytes.append(0x00) - if val < 0: - bytes = map( lambda x : x ^ 0xFF, bytes ) - bytes.reverse() - - return string.join(map(chr, bytes), '') - -def _decodeBitString(val): - 'der encoded value not including tag or length' - if not isinstance(val, types.StringType): - raise DerError, 'argument should be a string' - bitmasks = [0x80,0x40,0x20,0x10,0x08,0x04,0x02,0x01] - unused = ord( val[0] ) - bits = [] - for byte in val[1:]: - for j in range(8): - if ord(byte) & bitmasks[j]: - bits.append(1) - else: - bits.append(0) - if unused == 0: - return tuple(bits) - else: - return tuple(bits[:-unused]) - -def _encodeBitString(val): - 'list of true/false objects ie [0,1,1,0,1,1]' - if not (isinstance(val, types.ListType) or isinstance(val, types.TupleType)): - raise DerError, 'argument should be a list or tuple' - bitmasks = [0x80,0x40,0x20,0x10,0x08,0x04,0x02,0x01] - bytes = [] - fits, leftover = divmod(len(val), 8) - nobytes = fits - if leftover > 0: - nobytes = nobytes + 1 - if leftover: - unused = 8 - leftover - else: - unused = 0 - bytes.append(unused) - for i in range(nobytes): - byte = 0 - for j in range(8): - offset = j + i*8 - if offset < len(val): - if val[offset]: - byte = byte | bitmasks[j] - bytes.append(byte) - - return string.join(map(chr, bytes), '') - -def _decodeOid(val): - 'der encoded value not including tag or length' - if not isinstance(val, types.StringType): - raise DerError, 'argument should be a string' - arc12 = ord( val[0] ) - arc1, arc2 = divmod(arc12, 40) - oids = [arc1,arc2] - - total = 0 - for byte in val[1:]: - val = ord(byte) - if val & 0x80: - total = (total << 7) | (val ^ 0x80) - else: - total = (total << 7) | val - oids.append(total) - total = 0 - - return tuple(oids) - -def _encodeOid(val): - 'list of intgers' - if not (isinstance(val, types.ListType) or isinstance(val, types.TupleType)): - raise DerError, 'argument should be a list or tuple' - oids = [] - oids.append( chr(40 * val[0] + val[1]) ) - for val in val[2:]: - if val == 0: - oids.append( chr(0) ) - else: - bytes = [] - while val: - val, rem = divmod(val, 128) - bytes.append(rem | 0x80) - bytes[0] = bytes[0] ^ 0x80 - bytes.reverse() - oids.append( string.join(map(chr, bytes), '') ) - - return string.join(oids, '') - -def _decodeSequence(val): - 'der encoded value not including tag or length' - if not isinstance(val, types.StringType): - raise DerError, 'argument should be a string' - buf = cStringIO.StringIO(val) - buflen = len(val) - tvls = [] - while buf.tell() < buflen: - t = _TlvIo(buf) - t.read() - tvls.append(t) - return tuple(tvls) - -def _encodeSequence(val): - 'list of GenerlObjects' - if not (isinstance(val, types.ListType) or isinstance(val, types.TupleType)): - raise DerError, 'argument should be a list or tuple' - buf = cStringIO.StringIO() - for obj in val: - if obj or isinstance(obj, _GeneralObject): - obj.write(buf) - elif not obj.optional: - raise DerError, 'object not set which should be: %s' % obj - - return buf.getvalue() - -_addFragment(''' -<class> - <header> - <name>_GeneralObject</name> - </header> - <body> - <para> - <classname>_GeneralObject</classname> is the basis for all DER objects, - primitive or constructed. It defines the basic behaviour of an - object which is serialised using the tag, length and value - approach of DER. It is unlikely you would ever want to - instantiate one of these directly but I include a description - since many primatives don't override much of - <classname>_GeneralObject</classname>'s functions. - </para> - </body> -</class> -''') - -class _GeneralObject(object): - - _addFragment(''' - <constructor> - <header> - <memberof>_GeneralObject</memberof> - <parameter>normclass</parameter> - <parameter>normform</parameter> - <parameter>normnumber</parameter> - <parameter>encRoutine</parameter> - <parameter>decRoutine</parameter> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - <body> - <para> - <parameter>normclass</parameter> is the class of the object, - ei: universal, application, context or private. - <parameter>normform</parameter> is the form of the object, ei - primitive or constructed. <parameter>normnumber</parameter> is - the tag number of the object. - <parameter>encRoutine</parameter> is a function which takes a - value and encodes it according the appropriate DER rules. - <parameter>decRoutine</parameter> is a function which reads a - string value and returns a value which is more useful in - Python. <parameter>optional</parameter> is a boolean - indicating if this object is optional. The final parameter, - <parameter>default</parameter> is the base 64 encoded DER - value, which should be used as the default in leu of a value to - read or incase it is unset. - </para> - </body> - </constructor> - ''') - - def __init__(self, normclass, normform, normnumber, encRoutine, decRoutine, optional=0, default=''): - if not isinstance(normclass, types.IntType): - raise DerError, 'nomrclass argument should be an integer : %s' % normclass - if not isinstance(normform, types.IntType): - raise DerError, 'normform argument should be an integer : %s' % normform - if not isinstance(normnumber, types.IntType): - raise DerError, 'normnumber argument should be an integer : %s' % normnumber - if not isinstance(encRoutine, types.FunctionType): - raise DerError, 'encRoutine argument should be an function : %s' % encRoutine - if not isinstance(decRoutine, types.FunctionType): - raise DerError, 'decRoutine argument should be an function : %s' % decRoutine - if not isinstance(optional, types.IntType): - raise DerError, 'optional argument should be an integer : %s' % optional - if not isinstance(default, types.StringType): - raise DerError, 'default argument should be an String : %s' % default - self.normclass = normclass - self.normform = normform - self.normnumber = normnumber - self.encRoutine = encRoutine - self.decRoutine = decRoutine - self.value = None - self.optional = optional - self.default = default - self.reset() - - def _ioSafe(self): - 'is it safe to write this object' - if self.optional or self._isSet(): - return 1 - else: - return 0 - - def _isSet(self): - 'are the values of this object set or not' - if self.value is not None: - return 1 - else: - return 0 - - _addFragment(''' - <method> - <header> - <memberof>_GeneralObject</memberof> - <name>reset</name> - </header> - <body> - <para> - This function re-initialises the object, clearing the value or - setting it to any default. - </para> - </body> - </method> - ''') - def reset(self): - self.value = None - if self.default: - buf = cStringIO.StringIO( base64.decodestring( self.default ) ) - io = _TlvIo(buf) - io.read() - self.read(io) - - _addFragment(''' - <method> - <header> - <memberof>_GeneralObject</memberof> - <name>set</name> - <parameter>value</parameter> - </header> - <body> - <para> - This dosn't do much except store <parameter>value</parameter>, - presumably prior to writing the object. The correct values to - use would be determined by the encoder or decoder this class is - instantiated with. Be careful, there is some flexibility in - setting objects so you might find that once the object has been - written and read back in the value isn't identical. A good - example would be anything which contains a sequence(list or - tuple), all sequence objects are returned as tuples. - </para> - </body> - </method> - ''') - def set(self, value): - if value is not None: - self.value = value - - _addFragment(''' - <method> - <header> - <memberof>_GeneralObject</memberof> - <name>get</name> - </header> - <body> - <para> - Gets the value stored presumably after reading the object. - </para> - </body> - </method> - ''') - def get(self): - return self.value - - _addFragment(''' - <method> - <header> - <memberof>_GeneralObject</memberof> - <name>implied</name> - <parameter>impclass</parameter> - <parameter>impform</parameter> - <parameter>impnumber</parameter> - </header> - <body> - <para> - This function is used to change how the tag is written or read - for a particular object and should be called in the constructor - for derived objects. If you have an example of the structure you need to - process, Pete Gutmann's excellent - <application>dumpasn1</application> can be invaluable for - debugging objects. - </para> - </body> - </method> - ''') - def implied(self, impclass, impform, impnumber): - if not isinstance(impclass, types.IntType): - raise DerError, 'impclass argument should be an integer' - if not isinstance(impform, types.IntType): - raise DerError, 'impform argument should be an integer' - if not isinstance(impnumber, types.IntType): - raise DerError, 'impnumber argument should be an integer' - self.normclass = impclass - self.normform = impform - self.normnumber = impnumber - - _addFragment(''' - <method> - <header> - <memberof>_GeneralObject</memberof> - <name>read</name> - <parameter>io</parameter> - </header> - <body> - <para> - <parameter>io</parameter> should be a file like object. If the - object being read matches the expected class, form and tag the - value is read and decoded using - <function>decRoutine</function>. Else, if it has a default - that is read and stored. - </para> - <para> - The return value of this function does not indicate success but - whether this TLV was processed successfully. This bahaviour is - vital for processing constructed types since the object may be - optional or have a default. Failure to decode would be indicated - by an exception. - </para> - </body> - </method> - ''') - - def read(self, io=None): - - processDefOpt = 0 - if io is None: - processDefOpt = 1 - elif isinstance(io, _TlvIo): - if not io: - processDefOpt = 1 - else: - pos = io.tell() - io.seek(0,2) - if io.tell(): - io.seek(pos) - else: - processDefOpt = 1 - - if processDefOpt: - if self.optional or self.default: - self.reset() - return 0 - else: - raise DerError, 'no TLV is available to read in non-optional/non-default object: %s' % repr(self) - - if not isinstance(io, _TlvIo): - tmp = _TlvIo(io) - tmp.read() - io = tmp - - if io.tagclass != self.normclass or io.tagform != self.normform or io.tagnumber != self.normnumber: - if self.default or self.optional: - self.reset() - return 0 - else: - raise DerError, 'error in encoding, missing object:%s' % repr(self) - else: - derval = io.readValue() - self.value = self.decRoutine( derval ) - return 1 - - _addFragment(''' - <method> - <header> - <memberof>_GeneralObject</memberof> - <name>write</name> - <parameter>io</parameter> - </header> - <body> - <para> - If this object has not been set and is not optional and dosn't - have a default, a <classname>DerError</classname> exception will be raised - </para> - <para> - If no value has been set and this object is optional, nothing - is written. If this object's value is equal to the default, - nothing is written as stipulated by DER. Otherwise the value - is encoded and written. - </para> - </body> - </method> - ''') - - def write(self, file): - if not self._ioSafe(): - raise DerError, 'object not set which must be: %s' % repr(self) - elif self.optional and self.value is None: - pass - else: - buf = cStringIO.StringIO() - io = _TlvIo(buf) - io.tagclass = self.normclass - io.tagform = self.normform - io.tagnumber = self.normnumber - derval = self.encRoutine( self.value ) - io.length = len(derval) - io.write(derval) - if self.default: - if buf.getvalue() != base64.decodestring(self.default): - file.write( buf.getvalue() ) - else: - file.write( buf.getvalue() ) - - _addFragment(''' - <method> - <header> - <memberof>_GeneralObject</memberof> - <name>toString</name> - </header> - <body> - <para> - Encodes the value in DER and returns it as a string. - </para> - </body> - </method> - ''') - - def toString(self): - buf = cStringIO.StringIO() - self.write(buf) - return buf.getvalue() - - _addFragment(''' - <method> - <header> - <memberof>_GeneralObject</memberof> - <name>fromString</name> - </header> - <body> - <para> - Decodes the string and sets the value of this object. - </para> - </body> - </method> - ''') - - def fromString(self, value): - buf = cStringIO.StringIO(value) - self.read(buf) - -class Any(_GeneralObject): - - def __init__(self): - self.value = None - self.normclass = None - self.normform = None - self.normnumber = None - - def _ioSafe(self): - if self.optional or (self._isSet() and self.normclass is not None and self.normform is not None and self.normnumber is not None): - return 1 - else: - return 0 - - def setTag(self, klass, form, number): - self.normclass = klass - self.normform = form - self.normnumber = number - - def reset(self): - self.value = None - - def get(self): - return self.value - - def set(self, value): - self.value = value - - def write(self,file): - if not self._ioSafe(): - raise DerError, 'object not set which must be: %s' % repr(self) - elif self.optional and self.value is None: - pass - else: - buf = cStringIO.StringIO() - io = _TlvIo(buf) - io.tagclass = self.normclass - io.tagform = self.normform - io.tagnumber = self.normnumber - io.length = len(self.value) - io.write(self.value) - file.write(buf.getvalue()) - - def read(self, io=None): - - processDefOpt = 0 - if io is None: - processDefOpt = 1 - elif isinstance(io, _TlvIo): - if not io: - processDefOpt = 1 - else: - pos = io.tell() - io.seek(0,2) - if io.tell(): - io.seek(pos) - else: - processDefOpt = 1 - if processDefOpt: - if self.optional or self.default: - self.reset() - return 0 - else: - raise DerError, 'no TLV is available to read in non-optional/non-default object: %s' % repr(self) - - if not isinstance(io, _TlvIo): - tmp = _TlvIo(io) - tmp.read() - io = tmp - - self.value = io.readValue() - self.normclass = io.tagclass - self.normform = io.tagform - self.normnumber = io.tagnumber - -_addFragment(''' -<class> - <header> - <name>Boolean</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 BOOLEAN type. It can be set - with any object which can be tested for truth. - </para> - </body> -</class> -''') - -class Boolean(_GeneralObject): # 0x01 - - _addFragment(''' - <constructor> - <header> - <memberof>Boolean</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_BOOLEAN, _encodeBoolean, _decodeBoolean, optional, default) - -_addFragment(''' -<class> - <header> - <name>Integer</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 INTEGER type. It should be set - with a Python integer. - </para> - </body> -</class> -''') - -class Integer(_GeneralObject): # 0x02 - - _addFragment(''' - <constructor> - <header> - <memberof>Integer</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_INTEGER, _encodeInteger, _decodeInteger, optional, default) - -_addFragment(''' -<class> - <header> - <name>BitString</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 BIT STRING type. It should be set - with a sequence of integers. A non-zero number will set the bit, - zero will leave the bit unset. - </para> - </body> -</class> -''') - -class BitString(_GeneralObject): # 0x03 - - _addFragment(''' - <constructor> - <header> - <memberof>BitString</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_BITSTRING, _encodeBitString, _decodeBitString, optional, default) - -_addFragment(''' -<class> - <header> - <name>AltBitString</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 BIT STRING type. It differs from - the first <classname>BitString</classname> in that it's coding - routines treat values as binary data and do not interpret the data - in any way. Some application treat the - <classname>BIT STRING</classname> in the same way as - <classname>OCTET STRING</classname> type, hence this extra object. - </para> - </body> -</class> -''') - -class AltBitString(_GeneralObject): # 0x03 - - _addFragment(''' - <constructor> - <header> - <memberof>AltBitString</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_BITSTRING, lambda x : chr(0)+x, lambda x : x[1:], optional, default) - -_addFragment(''' -<class> - <header> - <name>OctetString</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 OCTET STRING type. This object - can be set with any binary data. - </para> - </body> -</class> -''') -class OctetString(_GeneralObject): # 0x04 - - _addFragment(''' - <constructor> - <header> - <memberof>OctetString</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_OCTETSTRING, lambda x : x, lambda x : x, optional, default) - -_addFragment(''' -<class> - <header> - <name>Null</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 NULL type. There is no point in - setting this object, the value will always be ignored when it is - written out. - </para> - </body> -</class> -''') -class Null(_GeneralObject): # 0x05 - - _addFragment(''' - <constructor> - <header> - <memberof>Null</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_NULL, lambda x : '', lambda x : '', optional, default) - self.value = '' - - def _ioSafe(self): - return 1 - - def reset(self): - self.value = '' - -_addFragment(''' -<class> - <header> - <name>Oid</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 OID type. This object should be - set with a list or tuple of integers defining an objects oid. - Please note that the first three arcs have a restricted set of - values, so encoding (5, 3, 7, 1) will produce bad results. - </para> - </body> -</class> -''') -class Oid(_GeneralObject): # 0x06 - - _addFragment(''' - <constructor> - <header> - <memberof>Oid</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_OID, _encodeOid, _decodeOid, optional, default) - -_addFragment(''' -<class> - <header> - <name>Enum</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 ENUM type. This should be set - using a Python integer, the meaning should be described in the - ASN1 document for the object you are encoding. - </para> - </body> -</class> -''') -class Enum(_GeneralObject): # 0x0A - - _addFragment(''' - <constructor> - <header> - <memberof>Enum</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_ENUMERATED, _encodeInteger, _decodeInteger, optional, default) - -_addFragment(''' -<class> - <header> - <name>Utf8String</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 UTF8String type. This object - should be set with a string. It is up to the application to ensure - it only contains valid characters for this type. - </para> - </body> -</class> -''') -class Utf8String(_GeneralObject): # 0x0C - - _addFragment(''' - <constructor> - <header> - <memberof>Utf8String</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_UTF8STRING, lambda x : x, lambda x : x, optional, default) - -_addFragment(''' -<class> - <header> - <name>NumericString</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 NumericString type. This should - object should be set with a string. It is up to the application to ensure - it only contains valid characters for this type. - </para> - </body> -</class> -''') -class NumericString(_GeneralObject): # 0x12 - - _addFragment(''' - <constructor> - <header> - <memberof>NumericString</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_NUMERICSTRING, lambda x : x, lambda x : x, optional, default) -_addFragment(''' -<class> - <header> - <name>PrintableString</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 PrintableString type. This should - object should be set with a string. It is up to the application to ensure - it only contains valid characters for this type. - </para> - </body> -</class> -''') -class PrintableString(_GeneralObject): # 0x13 - - _addFragment(''' - <constructor> - <header> - <memberof>PrintableString</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_PRINTABLESTRING, lambda x : x, lambda x : x, optional, default) - -_addFragment(''' -<class> - <header> - <name>T61String</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 T61String type. This object - should be set with a string. It is up to the application to ensure - it only contains valid characters for this type. - </para> - </body> -</class> -''') -class T61String(_GeneralObject): # 0x14 - - _addFragment(''' - <constructor> - <header> - <memberof>T61String</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_T61STRING, lambda x : x, lambda x : x, optional, default) - -_addFragment(''' -<class> - <header> - <name>VideotexString</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 VideotexString type. This should - object should be set with a string. It is up to the application to ensure - it only contains valid characters for this type. - </para> - </body> -</class> -''') -class VideotexString(_GeneralObject): # 0x15 - - _addFragment(''' - <constructor> - <header> - <memberof>VideotexString</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_VIDEOTEXSTRING, lambda x : x, lambda x : x, optional, default) - -_addFragment(''' -<class> - <header> - <name>IA5String</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 IA5String type. This object - should be set with a string. It is up to the application to ensure - it only contains valid characters for this type. - </para> - </body> -</class> -''') -class IA5String(_GeneralObject): # 0x16 - - _addFragment(''' - <constructor> - <header> - <memberof>IA5String</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_IA5STRING, lambda x : x, lambda x : x, optional, default) - -_addFragment(''' -<class> - <header> - <name>UtcTime</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 UTCTime type. This object should - be set with a string of the general format YYMMDDhhmmssZ. The - helper functions <function>time2utc</function> and - <function>utc2time</function> can be used to handle the conversion - from an integer to a string and back. - </para> - </body> -</class> -''') -class UtcTime(_GeneralObject): # 0x17 - - _addFragment(''' - <constructor> - <header> - <memberof>UtcTime</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_UTCTIME, lambda x : x, lambda x : x, optional, default) - -_addFragment(''' -<class> - <header> - <name>GeneralizedTime</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 GeneralizedTime type. This object should - be set with a string of the general format YYYYMMDDhhmmssZ. The - helper functions <function>time2utc</function> and - <function>utc2time</function> can be used to handle the conversion - from an integer to a string and back. - </para> - </body> -</class> -''') -class GeneralizedTime(_GeneralObject): # 0x18 - - _addFragment(''' - <constructor> - <header> - <memberof>GeneralizedTime</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_GENERALIZEDTIME, lambda x : x, lambda x : x, optional, default) - -_addFragment(''' -<class> - <header> - <name>GraphicString</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 GraphicString type. This should - object should be set with a string. It is up to the application to - ensure it only contains valid characters for this type. - </para> - </body> -</class> -''') -class GraphicString(_GeneralObject): # 0x19 - - _addFragment(''' - <constructor> - <header> - <memberof>GraphicString</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_GRAPHICSTRING, lambda x : x, lambda x : x, optional, default) - -_addFragment(''' -<class> - <header> - <name>VisibleString</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 VisibleString type. This should - object should be set with a string. It is up to the application to - ensure it only contains valid characters for this type. - </para> - </body> -</class> -''') -class VisibleString(_GeneralObject): # 0xC0 - - _addFragment(''' - <constructor> - <header> - <memberof>VisibleString</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_VISIBLESTRING, lambda x : x, lambda x : x, optional, default) - -_addFragment(''' -<class> - <header> - <name>GeneralString</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 GeneralString type. This should - object should be set with a string. It is up to the application to - ensure it only contains valid characters for this type. - </para> - </body> -</class> -''') -class GeneralString(_GeneralObject): # 0xC0 - - _addFragment(''' - <constructor> - <header> - <memberof>GeneralString</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_GENERALSTRING, lambda x : x, lambda x : x, optional, default) - -_addFragment(''' -<class> - <header> - <name>UniversalString</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 UniversalString type. This should - object should be set with a string. It is up to the application to - ensure it only contains valid characters for this type. - </para> - </body> -</class> -''') -class UniversalString(_GeneralObject): # 0xC0 - - _addFragment(''' - <constructor> - <header> - <memberof>UniversalString</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_UNIVERSALSTRING, lambda x : x, lambda x : x, optional, default) - -_addFragment(''' -<class> - <header> - <name>BmpString</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 BMPString type. This object - should be set with a string. It is up to the application to ensure - it only contains valid characters for this type. - </para> - </body> -</class> -''') -class BmpString(_GeneralObject): # 0xC0 - - _addFragment(''' - <constructor> - <header> - <memberof>BmpString</memberof> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - </constructor> - ''') - - def __init__(self, optional=0, default=''): - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_PRIMITIVE, TAG_BMPSTRING, lambda x : x, lambda x : x, optional, default) - -_addFragment(''' -<class> - <header> - <name>Sequence</name> - <super>_GeneralObject</super> - </header> - <body> - <para> - This object represents the ASN1 SEQUENCE type. - </para> - </body> -</class> -''') -class Sequence(_GeneralObject): # 0x10 - - _addFragment(''' - <constructor> - <header> - <memberof>Sequence</memberof> - <super>_GeneralObject</super> - <parameter>contents</parameter> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - <body> - <para> - The <parameter>contents</parameter> should be a list or tuple containing - the contents of the sequence. - Two important members are initialised this this constructor. - First <constant>self.next</constant> this is used to keep track - of which TLVs in this sequence has been read succesfully. The second, - <constant>self.contents</constant> should be set to the list of - objects stored in this sequence. Note that the order they are - specified in is the order in which they are written or read. - </para> - </body> - </constructor> - ''') - - def __init__(self, contents, optional=0, default=''): - self.contents = contents - self.next = 0 - _GeneralObject.__init__(self, CLASS_UNIVERSAL, FORM_CONSTRUCTED, TAG_SEQUENCE, _encodeSequence, _decodeSequence, optional, default) - - def _childRead(self, obj): - if self.next < len(self.value): - if obj.read( self.value[self.next] ): - self.next += 1 - else: - obj.read() - - _addFragment(''' - <method> - <header> - <memberof>Sequence</memberof> - <name>readContents</name> - <parameter>io</parameter> - <parameter>contents</parameter> - </header> - <body> - <para> - This function implements basic SEQUENCE like reading behaviour. - It will attempt to read each of the objects in - <parameter>contents</parameter> in turn from - <parameter>io</parameter>. It exists as a function, separate - from <function>read</function> for the benefit of the SEQUENCE - OF implementation. - </para> - <para> - The TLV of this SEQUENCE is read and parsed into a list of - TLVs, which are store in <constant>self.value</constant>, by - <classname>_GeneralObject</classname>.<function>read</function>. - Then <function>read</function> is called on each member to - process each TLV in turn. The next TLV is moved onto only when - a member returns TRUE from the read call. - </para> - </body> - </method> - ''') - - def readContents(self, io, contents): - if _GeneralObject.read( self, io ): - for item in contents: - Sequence._childRead( self, item ) - return 1 - else: - return 0 - - _addFragment(''' - <method> - <header> - <memberof>Sequence</memberof> - <name>read</name> - <parameter>io</parameter> - </header> - <body> - <para> - Most of the logic for reading is implemented in <function>readContents</function> - so it can be reused for <classname>SequenceOf</classname>'s - <function>read</function> function. - </para> - </body> - </method> - ''') - - def read(self, io=None): - self.next = 0 - return self.readContents(io, self.contents) - - _addFragment(''' - <method> - <header> - <memberof>Sequence</memberof> - <name>write</name> - <parameter>file</parameter> - </header> - <body> - <para> - <constant>self.value</constant> is set to the contents of this - SEQUENCE and then written by calling - <classname>_GeneralObject</classname>.<function>write</function> - whos encoder will call <function>write</function> of - each element in the list of contents in turn. - </para> - </body> - </method> - ''') - - def write(self, file): - if self._ioSafe(): - if self._isSet(): - _GeneralObject.set( self, self.contents ) - _GeneralObject.write( self, file ) - elif self.optional: - pass - else: - prob = self.findUnset() - raise DerError, '%s is not in a state which can be written, %s is unset' % (repr(self), repr(prob) ) - - _addFragment(''' - <method> - <header> - <memberof>Sequence</memberof> - <name>set</name> - <parameter>values</parameter> - </header> - <body> - <para> - Accessing and setting values for ASN1 objects is a bit of a - thorny issue. The problem stems from the arbitrary complexity - of the data and the possible levels of nesting, which in - practice are used and are quite massive. Designing a good general - approach is a bit tricky, perhaps nearly - impossible. I choose to use a most compact - form which is excellent for simple objects and is very concise. - </para> - <para> - <parameter>value</parameter> should be a list or tuple of - values. Each element of the list (or tuple) will be used in - turn to set a member. Defaults can be specified by using the - default value itself or <constant>None</constant>. Hence, for - SEQUENCES of SEQUENCES, SEQUENCES OF, SET and so on - <parameter>values</parameter> should consist of nested lists or - tuples. Look at the ASN1 specs for that object to figure out - exactly what these should look like. - </para> - </body> - </method> - ''') - - def set(self, values): - if self.contents is None: - raise DerError, 'the contents attribute should be set before using this object' - if not( isinstance(values, types.ListType) or isinstance(values, types.TupleType) ): - raise DerError, 'a sequence should be set with a list or tuple of values' - if len(values) != len(self.contents): - raise DerError, 'wrong number of values have been supplied to set %s. Expecting %i, got %i' % \ - (self.__class__.__name__, len(self.contents), len(values) ) - - i = 0 - for val in values: - self.contents[i].set(val) - i = i + 1 - - _addFragment(''' - <method> - <header> - <memberof>Sequence</memberof> - <name>get</name> - </header> - <body> - <para> - A tuple of the values of the contents of this sequence will be - returned. Hence, for SEQUENCES of SEQUENCES, SEQUENCES OF, SET - and so on nested tuples will be returned. - <function>get</function> always returns tuples even if a list - was used to set and object. - </para> - </body> - </method> - ''') - - def get(self): - if self.contents is None: - return _GeneralObject.get(self) - else: - results = [] - for obj in self.contents: - results.append( obj.get() ) - return tuple(results) - - def reset(self): - if self.contents is None: - raise DerError, 'this object has no members to set' - self.next = 0 - for obj in self.contents: - obj.reset() # clear all child objects prior to possible setting - # via default - _GeneralObject.reset(self) - - def _isSet(self): - if self.contents is None: - raise DerError, 'this object has no members to set' - for obj in self.contents: - if not obj._ioSafe(): - return 0 - return 1 - - def findUnset(self): - if self.contents is None: - raise DerError, 'this object has no members to check' - for obj in self.contents: - if not obj._ioSafe(): - return obj - - def _ioSafe(self): - if self.optional or self._isSet(): - return 1 - else: - for obj in self.contents: - if not obj._ioSafe(): - return 0 - return 1 - -_addFragment(''' -<class> - <header> - <name>SequenceOf</name> - <super>Sequence</super> - </header> - <body> - <para> - This object represents the ASN1 SEQUENCE OF construct. - </para> - </body> -</class> -''') -class SequenceOf(Sequence): - - _addFragment(''' - <constructor> - <header> - <memberof>SequenceOf</memberof> - <super>Sequence</super> - <parameter>contains</parameter> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - <body> - <para> - The <parameter>contains</parameter> should be the constructor - for the objects which this SEQUENCE OF contains. - </para> - </body> - </constructor> - ''') - - def __init__(self, contains, optional=0, default=''): - self.contains = contains - self.sequenceOf = [] - Sequence.__init__(self, [], optional, default) - - def _ioSafe(self): - return 1 - - def reset(self): - if self.contents is None: - raise DerError, 'this object has no members to set' - self.next = 0 - self.sequenceOf = [] - _GeneralObject.reset(self) - - def _isSet(self): - if self.sequenceOf: - for obj in self.contents: - if not obj._ioSafe(): - return 0 - return 1 - else: - return 0 - - def set(self, values): - if isinstance(values, types.NoneType): - return - objects = [] - for val in values: - obj = self.contains() - obj.set(val) - objects.append(obj) - self.sequenceOf = objects - - def get(self): - results = [] - for obj in self.sequenceOf: - results.append( obj.get() ) - return tuple(results) - - def read(self, io=None): - self.sequenceOf = [] - self.next = 0 - if _GeneralObject.read( self, io ): - for tagio in _GeneralObject.get(self): - value = self.contains() - value.read(tagio) - self.sequenceOf.append(value) - return 1 - else: - return 0 - - def write(self, file): - if not self._isSet() and self.optional: - pass - else: - _GeneralObject.set( self, self.sequenceOf ) - _GeneralObject.write( self, file ) - - def __len__(self): - return len(self.sequenceOf) - - def __getitem__(self, key): - return self.sequenceOf[key] - - def __iter__(self): - for i in self.sequenceOf: - yield(i) - - def __contains__(self, item): - return item in self.sequenceOf - -_addFragment(''' -<class> - <header> - <name>Set</name> - <super>Sequence</super> - </header> - <body> - <para> - This object represents the ASN1 Set type. - </para> - </body> -</class> -''') -class Set(Sequence): # 0x11 - - _addFragment(''' - <constructor> - <header> - <memberof>Set</memberof> - <super>Sequence</super> - <parameter>contents</parameter> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - <body> - <para> - The <parameter>contents</parameter> should be a list containing - the contents of the sequence. - </para> - </body> - </constructor> - ''') - - def __init__(self, contents, optional=0, default=''): - Sequence.__init__(self, contents, optional, default) - self.normnumber = TAG_SET - -_addFragment(''' -<class> - <header> - <name>SetOf</name> - <super>SequenceOf</super> - </header> - <body> - <para> - This object represents the ASN1 SET OF construct. - </para> - </body> -</class> -''') -class SetOf(SequenceOf): - - _addFragment(''' - <constructor> - <header> - <memberof>SetOf</memberof> - <super>SequenceOf</super> - <parameter>contains</parameter> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - <body> - <para> - The <parameter>contains</parameter> should be the constructor - for the objects which this SET OF contains. - </para> - </body> - </constructor> - ''') - - def __init__(self, contains, optional=0, default=''): - SequenceOf.__init__(self, contains, optional, default) - self.normnumber = TAG_SET - -_addFragment(''' -<class> - <header> - <name>Explicit</name> - <super>Sequence</super> - </header> - <body> - <para> - Explicit objects support the DER concept of explicit tagging. In - general they behave just like a SEQUENCE which must have only one - element. See below for other differences. - </para> - </body> -</class> -''') -class Explicit(Sequence): - - _addFragment(''' - <constructor> - <header> - <memberof>Explicit</memberof> - <super>Sequence</super> - <parameter>expclass</parameter> - <parameter>expform</parameter> - <parameter>expnumber</parameter> - <parameter>contents</parameter> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - <body> - <para> - <parameter>expclass</parameter>, - <parameter>expform</parameter>, - <parameter>expnumber</parameter> should be as - specified in the ASN1 documentation for this object. - <parameter>contents</parameter> should be an object instance - such as <classname>Integer</classname>, - <classname>Oid</classname> or a derived object which supports - the <classname>_GeneralObjec</classname> interface. - </para> - </body> - </constructor> - ''') - - def __init__(self, expclass, expform, expnumber, contents, optional=0, default=''): - self.contents = [contents] - self.next = 0 - _GeneralObject.__init__(self, expclass, expform, expnumber, _encodeSequence, _decodeSequence, optional, default) - - _addFragment(''' - <method> - <header> - <memberof>Explicit</memberof> - <name>set</name> - <parameter>value</parameter> - </header> - <body> - <para> - <parameter>value</parameter> is passed direct to - <function>set</function> of the explicit object, so it should - not be placed in a list or tuple(unless you are setting a constructed - object). - </para> - </body> - </method> - ''') - def set(self, value): - return Sequence.set(self, [value]) - - _addFragment(''' - <method> - <header> - <memberof>Explicit</memberof> - <name>get</name> - </header> - <body> - <para> - The value of explicit object is returned and not - put in a tuple. - </para> - </body> - </method> - ''') - def get(self): - return Sequence.get(self)[0] - -_addFragment(''' -<class> - <header> - <name>Choice</name> - </header> - <body> - <para> - This object represents the ASN1 Choice type. - </para> - </body> -</class> -''') -class Choice(object): - - _addFragment(''' - <constructor> - <header> - <memberof>Choice</memberof> - <parameter>choices</parameter> - <parameter>optional=0</parameter> - <parameter>default=''</parameter> - </header> - <body> - <para> - <parameter>choices</parameter> should be a dictionary of - objects which support the <classname>_GeneralObject</classname> - interface. The key being the name of the choice specified in the - ASN1 documentation. <parameter>optional</parameter> is a boolean - indicating if this object is optional. The final parameter, - <parameter>default</parameter> is the base 64 encoded DER - value, which should be used as the default in leu of a value to - read or incase it is unset. If neither - <parameter>optional</parameter> or - <parameter>default</parameter> is not set then the first choice - which is optional or has a default will be honored. - </para> - </body> - </constructor> - ''') - - def __init__(self, choices, optional=0, default=''): - self.value = None - self.choices = choices - self.optional = optional - self.default = default - self.choice = None - self.reset() - - def _ioSafe(self): - if self.optional or self._isSet(): - return 1 - elif self.choice and self.choices[ self.choice ]._ioSafe(): - return 1 - else: - return 0 - - def _isSet(self): - if self.choice and self.choices[self.choice]._isSet(): - return 1 - else: - return 0 - - _addFragment(''' - <method> - <header> - <memberof>Choice</memberof> - <name>reset</name> - </header> - <body> - <para> - This function re-initialises the object, clearing the value or - setting it to any default. - </para> - </body> - </method> - ''') - def reset(self): - self.value = None - self.choice = None - if self.default: - buf = cStringIO.StringIO( base64.decodestring( self.default ) ) - io = _TlvIo(buf) - io.read() - self.read(io) - else: - for key in self.choices.keys(): - self.choices[key].reset() - if self.choices[key]._ioSafe(): - self.choice = key - break; - - - _addFragment(''' - <method> - <header> - <memberof>Choice</memberof> - <name>set</name> - <parameter>value</parameter> - </header> - <body> - <para> - <parameter>value</parameter> should be a list or tuple with two - elements. The first value should be the name of the choice to - be set and the second the value to set it with. - </para> - </body> - </method> - ''') - def set(self, val): - if val is None: - return - if not (isinstance(val, types.ListType) or isinstance(val, types.TupleType)): - raise DerError, 'argument should be a list or tuple' - if not self.choices.has_key( val[0] ): - raise DerError, 'unknown choice: %s' % val[0] - self.choices[ val[0] ].set(val[1]) - self.choice = val[0] - - _addFragment(''' - <method> - <header> - <memberof>Choice</memberof> - <name>get</name> - </header> - <body> - <para> - This function will return tuple with two elements. The first - value will be the name of the choice which was set and the second - the value it was set to. - </para> - </body> - </method> - ''') - - def get(self): - if self._isSet(): - return (self.choice, self.choices[ self.choice ].get()) - else: - return None - - _addFragment(''' - <method> - <header> - <memberof>Choice</memberof> - <name>toString</name> - </header> - <body> - <para> - Encodes the value in DER and returns it as a string. - </para> - </body> - </method> - ''') - - def toString(self): - buf = cStringIO.StringIO() - self.write(buf) - return buf.getvalue() - - _addFragment(''' - <method> - <header> - <memberof>Choice</memberof> - <name>fromString</name> - </header> - <body> - <para> - Decodes the string and sets the value of this object. - </para> - </body> - </method> - ''') - - def fromString(self, value): - buf = cStringIO.StringIO(value) - self.read(buf) - - _addFragment(''' - <method> - <header> - <memberof>Choice</memberof> - <name>read</name> - <parameter>io</parameter> - </header> - <body> - <para> - <parameter>io</parameter> should be a file like object. If the - object being read matches the expected class, form and tag the - value is read and decoded using - <function>decRoutine</function>. Else, if it has a default - that is read and stored. - </para> - <para> - The return value of this function does not indicate success but - whether this TLV was processed successfully. This bahaviour is - vital for processing constructed types since the object may be - optional or have a default. Failure to decode would be indicated - by an exception. - </para> - </body> - </method> - ''') - - def _readChoices(self, io): - for key in self.choices.keys(): - try: - readindicator = self.choices[key].read(io) - self.choice = key - break; - except DerError: - if DEBUG: - traceback.print_exc() - return readindicator - - def read(self, io=None): - - self.choice = None - processDefOpt = 0 - readindicator = 0 - - if io is None: - processDefOpt = 1 - elif isinstance(io, _TlvIo): - if not io: - processDefOpt = 1 - else: - pos = io.tell() - io.seek(0,2) - if io.tell(): - io.seek(pos) - else: - processDefOpt = 1 - - if processDefOpt: - if self.optional or self.default: - self.reset() - return 0 - else: - readindicator = self._readChoices(io) - for key in self.choices.keys(): - try: - readindicator = self.choices[key].read(io) - self.choice = key - break; - except DerError: - if DEBUG: - traceback.print_exc() - if not self._isSet(): - raise DerError, 'no TLV is available to read in non-optional/non-default object: %s' % repr(self) - else: - return readindicator - - if not isinstance(io, _TlvIo): - tmp = _TlvIo(io) - tmp.read() - io = tmp - - for key in self.choices.keys(): - try: - if self.choices[key].read(io): - self.choice = key - readindicator = 1 - break; - except DerError: - if DEBUG: - traceback.print_exc() - - if not self._isSet(): - self.reset() - else: - return readindicator - - _addFragment(''' - <method> - <header> - <memberof>Choice</memberof> - <name>write</name> - <parameter>file</parameter> - </header> - <body> - <para> - If this object has not been set and is not optional and dosn't - have a default, a <classname>DerError</classname> exception will be raised - </para> - <para> - If no value has been set and this object is optional, nothing - is written. If this object's value is equal to the default, - nothing is written as stipulated by DER. Otherwise the value - is encoded and written. - </para> - </body> - </method> - ''') - def write(self,file): - if self.optional and not self.choice: - pass - elif not self.choice: - raise DerError, 'choice not set' - elif self.choice: - if self.default: - defval = base64.decodestring( self.default ) - if defval != self.choices[ self.choice ].toString(): - self.choices[ self.choice ].write(file) - else: - self.choices[ self.choice ].write(file) - else: - raise DerError, 'an internal error has occured: %s' % repr(self) - - |