Fix invalid DEFINED BY offset calculation for EXPL tagged objects

[pyderasn.git] / pyderasn.py

diff --git a/pyderasn.py b/pyderasn.py
index cc44e24c91293ca4ffe85ba7684279e87718925c..cd96a33200a1a6a7a801bc29b6aa95ca48b860cf 100755 (executable)
--- a/pyderasn.py
+++ b/pyderasn.py
@@ -3642,6 +3642,8 @@ class Sequence(Obj):
     >>> tbs = TBSCertificate()
     >>> tbs["version"] = Version("v2") # no need to explicitly add ``expl``
 
+    Assign ``None`` to remove value from sequence.
+
     You can know if value exists/set in the sequence and take its value:
 
     >>> "extnID" in ext, "extnValue" in ext, "critical" in ext
@@ -3873,7 +3875,10 @@ class Sequence(Obj):
                         )
                         defined_value, defined_tail = defined_spec.decode(
                             memoryview(bytes(_value)),
-                            sub_offset + value.tlen + value.llen,
+                            sub_offset + (
+                                (value.tlen + value.llen + value.expl_tlen + value.expl_llen)
+                                if value.expled else (value.tlen + value.llen)
+                            ),
                             leavemm=True,
                             decode_path=sub_sub_decode_path,
                             ctx=ctx,
@@ -3889,7 +3894,10 @@ class Sequence(Obj):
                 else:
                     defined_value, defined_tail = defined_spec.decode(
                         memoryview(bytes(value)),
-                        sub_offset + value.tlen + value.llen,
+                        sub_offset + (
+                            (value.tlen + value.llen + value.expl_tlen + value.expl_llen)
+                            if value.expled else (value.tlen + value.llen)
+                        ),
                         leavemm=True,
                         decode_path=sub_decode_path + (decode_path_defby(defined_by),),
                         ctx=ctx,