You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
353 lines
13 KiB
353 lines
13 KiB
# BER encoder
|
|
from pyasn1.type import base, tag, univ, char, useful
|
|
from pyasn1.codec.ber import eoo
|
|
from pyasn1.compat.octets import int2oct, oct2int, ints2octs, null, str2octs
|
|
from pyasn1 import debug, error
|
|
|
|
class Error(Exception): pass
|
|
|
|
class AbstractItemEncoder:
|
|
supportIndefLenMode = 1
|
|
def encodeTag(self, t, isConstructed):
|
|
tagClass, tagFormat, tagId = t.asTuple() # this is a hotspot
|
|
v = tagClass | tagFormat
|
|
if isConstructed:
|
|
v = v|tag.tagFormatConstructed
|
|
if tagId < 31:
|
|
return int2oct(v|tagId)
|
|
else:
|
|
s = int2oct(tagId&0x7f)
|
|
tagId = tagId >> 7
|
|
while tagId:
|
|
s = int2oct(0x80|(tagId&0x7f)) + s
|
|
tagId = tagId >> 7
|
|
return int2oct(v|0x1F) + s
|
|
|
|
def encodeLength(self, length, defMode):
|
|
if not defMode and self.supportIndefLenMode:
|
|
return int2oct(0x80)
|
|
if length < 0x80:
|
|
return int2oct(length)
|
|
else:
|
|
substrate = null
|
|
while length:
|
|
substrate = int2oct(length&0xff) + substrate
|
|
length = length >> 8
|
|
substrateLen = len(substrate)
|
|
if substrateLen > 126:
|
|
raise Error('Length octets overflow (%d)' % substrateLen)
|
|
return int2oct(0x80 | substrateLen) + substrate
|
|
|
|
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
|
|
raise Error('Not implemented')
|
|
|
|
def _encodeEndOfOctets(self, encodeFun, defMode):
|
|
if defMode or not self.supportIndefLenMode:
|
|
return null
|
|
else:
|
|
return encodeFun(eoo.endOfOctets, defMode)
|
|
|
|
def encode(self, encodeFun, value, defMode, maxChunkSize):
|
|
substrate, isConstructed = self.encodeValue(
|
|
encodeFun, value, defMode, maxChunkSize
|
|
)
|
|
tagSet = value.getTagSet()
|
|
if tagSet:
|
|
if not isConstructed: # primitive form implies definite mode
|
|
defMode = 1
|
|
return self.encodeTag(
|
|
tagSet[-1], isConstructed
|
|
) + self.encodeLength(
|
|
len(substrate), defMode
|
|
) + substrate + self._encodeEndOfOctets(encodeFun, defMode)
|
|
else:
|
|
return substrate # untagged value
|
|
|
|
class EndOfOctetsEncoder(AbstractItemEncoder):
|
|
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
|
|
return null, 0
|
|
|
|
class ExplicitlyTaggedItemEncoder(AbstractItemEncoder):
|
|
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
|
|
if isinstance(value, base.AbstractConstructedAsn1Item):
|
|
value = value.clone(tagSet=value.getTagSet()[:-1],
|
|
cloneValueFlag=1)
|
|
else:
|
|
value = value.clone(tagSet=value.getTagSet()[:-1])
|
|
return encodeFun(value, defMode, maxChunkSize), 1
|
|
|
|
explicitlyTaggedItemEncoder = ExplicitlyTaggedItemEncoder()
|
|
|
|
class BooleanEncoder(AbstractItemEncoder):
|
|
supportIndefLenMode = 0
|
|
_true = ints2octs((1,))
|
|
_false = ints2octs((0,))
|
|
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
|
|
return value and self._true or self._false, 0
|
|
|
|
class IntegerEncoder(AbstractItemEncoder):
|
|
supportIndefLenMode = 0
|
|
supportCompactZero = False
|
|
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
|
|
if value == 0: # shortcut for zero value
|
|
if self.supportCompactZero:
|
|
# this seems to be a correct way for encoding zeros
|
|
return null, 0
|
|
else:
|
|
# this seems to be a widespread way for encoding zeros
|
|
return ints2octs((0,)), 0
|
|
octets = []
|
|
value = int(value) # to save on ops on asn1 type
|
|
while 1:
|
|
octets.insert(0, value & 0xff)
|
|
if value == 0 or value == -1:
|
|
break
|
|
value = value >> 8
|
|
if value == 0 and octets[0] & 0x80:
|
|
octets.insert(0, 0)
|
|
while len(octets) > 1 and \
|
|
(octets[0] == 0 and octets[1] & 0x80 == 0 or \
|
|
octets[0] == 0xff and octets[1] & 0x80 != 0):
|
|
del octets[0]
|
|
return ints2octs(octets), 0
|
|
|
|
class BitStringEncoder(AbstractItemEncoder):
|
|
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
|
|
if not maxChunkSize or len(value) <= maxChunkSize*8:
|
|
r = {}; l = len(value); p = 0; j = 7
|
|
while p < l:
|
|
i, j = divmod(p, 8)
|
|
r[i] = r.get(i,0) | value[p]<<(7-j)
|
|
p = p + 1
|
|
keys = list(r); keys.sort()
|
|
return int2oct(7-j) + ints2octs([r[k] for k in keys]), 0
|
|
else:
|
|
pos = 0; substrate = null
|
|
while 1:
|
|
# count in octets
|
|
v = value.clone(value[pos*8:pos*8+maxChunkSize*8])
|
|
if not v:
|
|
break
|
|
substrate = substrate + encodeFun(v, defMode, maxChunkSize)
|
|
pos = pos + maxChunkSize
|
|
return substrate, 1
|
|
|
|
class OctetStringEncoder(AbstractItemEncoder):
|
|
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
|
|
if not maxChunkSize or len(value) <= maxChunkSize:
|
|
return value.asOctets(), 0
|
|
else:
|
|
pos = 0; substrate = null
|
|
while 1:
|
|
v = value.clone(value[pos:pos+maxChunkSize])
|
|
if not v:
|
|
break
|
|
substrate = substrate + encodeFun(v, defMode, maxChunkSize)
|
|
pos = pos + maxChunkSize
|
|
return substrate, 1
|
|
|
|
class NullEncoder(AbstractItemEncoder):
|
|
supportIndefLenMode = 0
|
|
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
|
|
return null, 0
|
|
|
|
class ObjectIdentifierEncoder(AbstractItemEncoder):
|
|
supportIndefLenMode = 0
|
|
precomputedValues = {
|
|
(1, 3, 6, 1, 2): (43, 6, 1, 2),
|
|
(1, 3, 6, 1, 4): (43, 6, 1, 4)
|
|
}
|
|
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
|
|
oid = value.asTuple()
|
|
if oid[:5] in self.precomputedValues:
|
|
octets = self.precomputedValues[oid[:5]]
|
|
index = 5
|
|
else:
|
|
if len(oid) < 2:
|
|
raise error.PyAsn1Error('Short OID %s' % (value,))
|
|
|
|
# Build the first twos
|
|
if oid[0] > 6 or oid[1] > 39 or oid[0] == 6 and oid[1] > 15:
|
|
raise error.PyAsn1Error(
|
|
'Initial sub-ID overflow %s in OID %s' % (oid[:2], value)
|
|
)
|
|
octets = (oid[0] * 40 + oid[1],)
|
|
index = 2
|
|
|
|
# Cycle through subids
|
|
for subid in oid[index:]:
|
|
if subid > -1 and subid < 128:
|
|
# Optimize for the common case
|
|
octets = octets + (subid & 0x7f,)
|
|
elif subid < 0 or subid > 0xFFFFFFFF:
|
|
raise error.PyAsn1Error(
|
|
'SubId overflow %s in %s' % (subid, value)
|
|
)
|
|
else:
|
|
# Pack large Sub-Object IDs
|
|
res = (subid & 0x7f,)
|
|
subid = subid >> 7
|
|
while subid > 0:
|
|
res = (0x80 | (subid & 0x7f),) + res
|
|
subid = subid >> 7
|
|
# Add packed Sub-Object ID to resulted Object ID
|
|
octets += res
|
|
|
|
return ints2octs(octets), 0
|
|
|
|
class RealEncoder(AbstractItemEncoder):
|
|
supportIndefLenMode = 0
|
|
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
|
|
if value.isPlusInfinity():
|
|
return int2oct(0x40), 0
|
|
if value.isMinusInfinity():
|
|
return int2oct(0x41), 0
|
|
m, b, e = value
|
|
if not m:
|
|
return null, 0
|
|
if b == 10:
|
|
return str2octs('\x03%dE%s%d' % (m, e == 0 and '+' or '', e)), 0
|
|
elif b == 2:
|
|
fo = 0x80 # binary enoding
|
|
if m < 0:
|
|
fo = fo | 0x40 # sign bit
|
|
m = -m
|
|
while int(m) != m: # drop floating point
|
|
m *= 2
|
|
e -= 1
|
|
while m & 0x1 == 0: # mantissa normalization
|
|
m >>= 1
|
|
e += 1
|
|
eo = null
|
|
while e not in (0, -1):
|
|
eo = int2oct(e&0xff) + eo
|
|
e >>= 8
|
|
if e == 0 and eo and oct2int(eo[0]) & 0x80:
|
|
eo = int2oct(0) + eo
|
|
n = len(eo)
|
|
if n > 0xff:
|
|
raise error.PyAsn1Error('Real exponent overflow')
|
|
if n == 1:
|
|
pass
|
|
elif n == 2:
|
|
fo |= 1
|
|
elif n == 3:
|
|
fo |= 2
|
|
else:
|
|
fo |= 3
|
|
eo = int2oct(n//0xff+1) + eo
|
|
po = null
|
|
while m:
|
|
po = int2oct(m&0xff) + po
|
|
m >>= 8
|
|
substrate = int2oct(fo) + eo + po
|
|
return substrate, 0
|
|
else:
|
|
raise error.PyAsn1Error('Prohibited Real base %s' % b)
|
|
|
|
class SequenceEncoder(AbstractItemEncoder):
|
|
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
|
|
value.setDefaultComponents()
|
|
value.verifySizeSpec()
|
|
substrate = null; idx = len(value)
|
|
while idx > 0:
|
|
idx = idx - 1
|
|
if value[idx] is None: # Optional component
|
|
continue
|
|
component = value.getDefaultComponentByPosition(idx)
|
|
if component is not None and component == value[idx]:
|
|
continue
|
|
substrate = encodeFun(
|
|
value[idx], defMode, maxChunkSize
|
|
) + substrate
|
|
return substrate, 1
|
|
|
|
class SequenceOfEncoder(AbstractItemEncoder):
|
|
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
|
|
value.verifySizeSpec()
|
|
substrate = null; idx = len(value)
|
|
while idx > 0:
|
|
idx = idx - 1
|
|
substrate = encodeFun(
|
|
value[idx], defMode, maxChunkSize
|
|
) + substrate
|
|
return substrate, 1
|
|
|
|
class ChoiceEncoder(AbstractItemEncoder):
|
|
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
|
|
return encodeFun(value.getComponent(), defMode, maxChunkSize), 1
|
|
|
|
class AnyEncoder(OctetStringEncoder):
|
|
def encodeValue(self, encodeFun, value, defMode, maxChunkSize):
|
|
return value.asOctets(), defMode == 0
|
|
|
|
tagMap = {
|
|
eoo.endOfOctets.tagSet: EndOfOctetsEncoder(),
|
|
univ.Boolean.tagSet: BooleanEncoder(),
|
|
univ.Integer.tagSet: IntegerEncoder(),
|
|
univ.BitString.tagSet: BitStringEncoder(),
|
|
univ.OctetString.tagSet: OctetStringEncoder(),
|
|
univ.Null.tagSet: NullEncoder(),
|
|
univ.ObjectIdentifier.tagSet: ObjectIdentifierEncoder(),
|
|
univ.Enumerated.tagSet: IntegerEncoder(),
|
|
univ.Real.tagSet: RealEncoder(),
|
|
# Sequence & Set have same tags as SequenceOf & SetOf
|
|
univ.SequenceOf.tagSet: SequenceOfEncoder(),
|
|
univ.SetOf.tagSet: SequenceOfEncoder(),
|
|
univ.Choice.tagSet: ChoiceEncoder(),
|
|
# character string types
|
|
char.UTF8String.tagSet: OctetStringEncoder(),
|
|
char.NumericString.tagSet: OctetStringEncoder(),
|
|
char.PrintableString.tagSet: OctetStringEncoder(),
|
|
char.TeletexString.tagSet: OctetStringEncoder(),
|
|
char.VideotexString.tagSet: OctetStringEncoder(),
|
|
char.IA5String.tagSet: OctetStringEncoder(),
|
|
char.GraphicString.tagSet: OctetStringEncoder(),
|
|
char.VisibleString.tagSet: OctetStringEncoder(),
|
|
char.GeneralString.tagSet: OctetStringEncoder(),
|
|
char.UniversalString.tagSet: OctetStringEncoder(),
|
|
char.BMPString.tagSet: OctetStringEncoder(),
|
|
# useful types
|
|
useful.GeneralizedTime.tagSet: OctetStringEncoder(),
|
|
useful.UTCTime.tagSet: OctetStringEncoder()
|
|
}
|
|
|
|
# Type-to-codec map for ambiguous ASN.1 types
|
|
typeMap = {
|
|
univ.Set.typeId: SequenceEncoder(),
|
|
univ.SetOf.typeId: SequenceOfEncoder(),
|
|
univ.Sequence.typeId: SequenceEncoder(),
|
|
univ.SequenceOf.typeId: SequenceOfEncoder(),
|
|
univ.Choice.typeId: ChoiceEncoder(),
|
|
univ.Any.typeId: AnyEncoder()
|
|
}
|
|
|
|
class Encoder:
|
|
def __init__(self, tagMap, typeMap={}):
|
|
self.__tagMap = tagMap
|
|
self.__typeMap = typeMap
|
|
|
|
def __call__(self, value, defMode=1, maxChunkSize=0):
|
|
debug.logger & debug.flagEncoder and debug.logger('encoder called in %sdef mode, chunk size %s for type %s, value:\n%s' % (not defMode and 'in' or '', maxChunkSize, value.__class__.__name__, value.prettyPrint()))
|
|
tagSet = value.getTagSet()
|
|
if len(tagSet) > 1:
|
|
concreteEncoder = explicitlyTaggedItemEncoder
|
|
else:
|
|
if value.typeId is not None and value.typeId in self.__typeMap:
|
|
concreteEncoder = self.__typeMap[value.typeId]
|
|
elif tagSet in self.__tagMap:
|
|
concreteEncoder = self.__tagMap[tagSet]
|
|
else:
|
|
tagSet = value.baseTagSet
|
|
if tagSet in self.__tagMap:
|
|
concreteEncoder = self.__tagMap[tagSet]
|
|
else:
|
|
raise Error('No encoder for %s' % (value,))
|
|
debug.logger & debug.flagEncoder and debug.logger('using value codec %s chosen by %r' % (concreteEncoder.__class__.__name__, tagSet))
|
|
substrate = concreteEncoder.encode(
|
|
self, value, defMode, maxChunkSize
|
|
)
|
|
debug.logger & debug.flagEncoder and debug.logger('built %s octets of substrate: %s\nencoder completed' % (len(substrate), debug.hexdump(substrate)))
|
|
return substrate
|
|
|
|
encode = Encoder(tagMap, typeMap)
|
|
|