ASN.1 codecs to silently enforce proper length/chunk modes

5 files changed, 26 insertions, 60 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index b1bfea4..7d7ff33 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -5,6 +5,9 @@ Revision 0.3.5, released XX-09-2017
 - Codecs signatures unified and pass **options through the call chain
 - Explicit tag encoding optimized to avoid unnecessary copying
 - End-of-octets sentinel encoding optimized
+- Refactored ASN.1 codecs properties to silently enforce proper length and
+  chunk size encoding modes
+- Fixed DER encoder to always produce primitive encoding
 
 Revision 0.3.4, released 07-09-2017
 -----------------------------------
diff --git a/pyasn1/codec/ber/encoder.py b/pyasn1/codec/ber/encoder.py
index dee13e5..b43e209 100644
--- a/pyasn1/codec/ber/encoder.py
+++ b/pyasn1/codec/ber/encoder.py
@@ -460,7 +460,8 @@ typeMap = {
 
 
 class Encoder(object):
-    supportIndefLength = True
+    fixedDefLengthMode = None
+    fixedChunkSize = None
 
     # noinspection PyDefaultArgument
     def __init__(self, tagMap, typeMap={}):
@@ -468,8 +469,6 @@ class Encoder(object):
         self.__typeMap = typeMap
 
     def __call__(self, value, **options):
-        if not options.get('defMode', True) and not self.supportIndefLength:
-            raise error.PyAsn1Error('Indefinite length encoding not supported by this codec')
 
         if debug.logger & debug.flagEncoder:
             logger = debug.logger
@@ -479,6 +478,12 @@ class Encoder(object):
         if logger:
             logger('encoder called in %sdef mode, chunk size %s for type %s, value:\n%s' % (not defMode and 'in' or '', maxChunkSize, value.prettyPrintType(), value.prettyPrint()))
 
+        if self.fixedDefLengthMode is not None:
+            options.update(defMode=self.fixedDefLengthMode)
+
+        if self.fixedChunkSize is not None:
+            options.update(maxChunkSize=self.fixedChunkSize)
+
         tagSet = value.tagSet
 
         try:
diff --git a/pyasn1/codec/cer/encoder.py b/pyasn1/codec/cer/encoder.py
index 50cb346..dd3e2b4 100644
--- a/pyasn1/codec/cer/encoder.py
+++ b/pyasn1/codec/cer/encoder.py
@@ -22,22 +22,6 @@ class BooleanEncoder(encoder.IntegerEncoder):
         return substrate, False, False
 
 
-class BitStringEncoder(encoder.BitStringEncoder):
-    def encodeValue(self, value, encodeFun, **options):
-        options.update(maxChunkSize=1000)
-        return encoder.BitStringEncoder.encodeValue(
-            self, value, encodeFun, **options
-        )
-
-
-class OctetStringEncoder(encoder.OctetStringEncoder):
-    def encodeValue(self, value, encodeFun, **options):
-        options.update(maxChunkSize=1000)
-        return encoder.OctetStringEncoder.encodeValue(
-            self, value, encodeFun, **options
-        )
-
-
 class RealEncoder(encoder.RealEncoder):
     def _chooseEncBase(self, value):
         m, b, e = value
@@ -83,7 +67,7 @@ class TimeEncoderMixIn(object):
         )
 
 
-class GeneralizedTimeEncoder(TimeEncoderMixIn, OctetStringEncoder):
+class GeneralizedTimeEncoder(TimeEncoderMixIn, encoder.OctetStringEncoder):
     minLength = 12
     maxLength = 19
 
@@ -181,8 +165,6 @@ class SequenceOfEncoder(encoder.SequenceOfEncoder):
 tagMap = encoder.tagMap.copy()
 tagMap.update({
     univ.Boolean.tagSet: BooleanEncoder(),
-    univ.BitString.tagSet: BitStringEncoder(),
-    univ.OctetString.tagSet: OctetStringEncoder(),
     univ.Real.tagSet: RealEncoder(),
     useful.GeneralizedTime.tagSet: GeneralizedTimeEncoder(),
     useful.UTCTime.tagSet: UTCTimeEncoder(),
@@ -194,8 +176,6 @@ tagMap.update({
 typeMap = encoder.typeMap.copy()
 typeMap.update({
     univ.Boolean.typeId: BooleanEncoder(),
-    univ.BitString.typeId: BitStringEncoder(),
-    univ.OctetString.typeId: OctetStringEncoder(),
     univ.Real.typeId: RealEncoder(),
     useful.GeneralizedTime.typeId: GeneralizedTimeEncoder(),
     useful.UTCTime.typeId: UTCTimeEncoder(),
@@ -208,7 +188,8 @@ typeMap.update({
 
 
 class Encoder(encoder.Encoder):
-    supportIndefLength = True
+    fixedDefLengthMode = False
+    fixedChunkSize = 1000
 
     def __call__(self, value, **options):
         if 'defMode' not in options:
diff --git a/pyasn1/codec/der/encoder.py b/pyasn1/codec/der/encoder.py
index 59dd512..d2992a9 100644
--- a/pyasn1/codec/der/encoder.py
+++ b/pyasn1/codec/der/encoder.py
@@ -10,18 +10,6 @@ from pyasn1.codec.cer import encoder
 __all__ = ['encode']
 
 
-class BitStringEncoder(encoder.BitStringEncoder):
-    def encodeValue(self, value, encodeFun, **options):
-        return encoder.BitStringEncoder.encodeValue(
-            self, value, encodeFun, **options
-        )
-
-class OctetStringEncoder(encoder.OctetStringEncoder):
-    def encodeValue(self, value, encodeFun, **options):
-        return encoder.OctetStringEncoder.encodeValue(
-            self, value, encodeFun, **options
-        )
-
 class SetOfEncoder(encoder.SetOfEncoder):
     @staticmethod
     def _sortComponents(components):
@@ -30,16 +18,12 @@ class SetOfEncoder(encoder.SetOfEncoder):
 
 tagMap = encoder.tagMap.copy()
 tagMap.update({
-    univ.BitString.tagSet: BitStringEncoder(),
-    univ.OctetString.tagSet: OctetStringEncoder(),
     # Set & SetOf have same tags
     univ.SetOf.tagSet: SetOfEncoder()
 })
 
 typeMap = encoder.typeMap.copy()
 typeMap.update({
-    univ.BitString.typeId: BitStringEncoder(),
-    univ.OctetString.typeId: OctetStringEncoder(),
     # Set & SetOf have same tags
     univ.Set.typeId: SetOfEncoder(),
     univ.SetOf.typeId: SetOfEncoder()
@@ -47,12 +31,8 @@ typeMap.update({
 
 
 class Encoder(encoder.Encoder):
-    supportIndefLength = False
-
-    def __call__(self, value, **options):
-        if 'defMode' not in options:
-            options.update(defMode=True)
-        return encoder.Encoder.__call__(self, value, **options)
+    fixedDefLengthMode = True
+    fixedChunkSize = 0
 
 #: Turns ASN.1 object into DER octet stream.
 #:
diff --git a/tests/codec/der/test_encoder.py b/tests/codec/der/test_encoder.py
index d30dfc1..354781a 100644
--- a/tests/codec/der/test_encoder.py
+++ b/tests/codec/der/test_encoder.py
@@ -17,31 +17,28 @@ from pyasn1.error import PyAsn1Error
 
 
 class OctetStringEncoderTestCase(unittest.TestCase):
-    def testShortMode(self):
+    def testDefModeShort(self):
         assert encoder.encode(
             univ.OctetString('Quick brown fox')
         ) == ints2octs((4, 15, 81, 117, 105, 99, 107, 32, 98, 114, 111, 119, 110, 32, 102, 111, 120))
 
-    def testIndefMode(self):
-        try:
-            encoder.encode(univ.OctetString('Quick brown'), defMode=False)
-        except PyAsn1Error:
-            pass
-        else:
-            assert 0, 'Indefinite length encoding tolerated'
-
-    def testChunkedMode(self):
+    def testDefModeLong(self):
         assert encoder.encode(
-            univ.OctetString('Quick brown'), maxChunkSize=2
-        ) == ints2octs((4, 11, 81, 117, 105, 99, 107, 32, 98, 114, 111, 119, 110))
+            univ.OctetString('Q' * 10000)
+        ) == ints2octs((4, 130, 39, 16) + (81,) * 10000)
 
 
 class BitStringEncoderTestCase(unittest.TestCase):
-    def testShortMode(self):
+    def testDefModeShort(self):
         assert encoder.encode(
             univ.BitString((1,))
         ) == ints2octs((3, 2, 7, 128))
 
+    def testDefModeLong(self):
+        assert encoder.encode(
+            univ.BitString((1,) * 80000)
+        ) == ints2octs((3, 130, 39, 17, 0) + (255,) * 10000)
+
 
 class SetOfEncoderTestCase(unittest.TestCase):
     def setUp(self):