[pyasn1-users] Parse Errors

[Mike M. <mik...@gm...>]

I've run into some problems decoding multiple extended tags starting
with 9F (9F02, 9F03, 9F06, etc).   If I make the following changes,
they decode perfectly.  The reason it's a problem is because the
tagId's end up being < 31.  This makes me wonder if the tag number
should be 0x80 after the SHL 7 instead of 0.  Otherwise it seems as
though (for instance) 82 and 9F02 would decode/encode incorrectly.

Applied against 1.8 (the tests still all pass, but I haven't worked on
the encoder side, obviously)

diff --git a/berdecoder.py b/berdecoder.py
index 61bfbce..4bf7ce4 100644
--- a/berdecoder.py
+++ b/berdecoder.py
@@ -643,8 +643,10 @@ class Decoder:
                     tagClass = t&0xC0
                     tagFormat = t&0x20
                     tagId = t&0x1F
+                    short = True
                     if tagId == 0x1F:
                         tagId = 0
+                        short = False
                         while 1:
                             if not substrate:
                                 raise error.SubstrateUnderrunError(
@@ -658,7 +660,7 @@ class Decoder:
                     lastTag = tag.Tag(
                         tagClass=tagClass, tagFormat=tagFormat, tagId=tagId
                     )
-                    if tagId < 31:
+                    if short:
                         # cache short tags
                         self.__tagCache[firstOctet] = lastTag
                 if tagSet is None: