Fix XML parsing errors caused by invalid characters in AD attributes

src/encoder/records/text.py

@@ -1,14 +1,32 @@
 import base64
 import datetime
+import re
 import struct
 from html.entities import codepoint2name
 from typing import Self
+from xml.sax.saxutils import escape as xml_escape
 
 from .constants import DICTIONARY
 from .datatypes import Decimal, MultiByteInt31
 from .record import record
 
 
+# Regex to match invalid XML 1.0 characters (control chars except tab, newline, carriage return)
+_INVALID_XML_CHARS = re.compile(r'[\x00-\x08\x0b\x0c\x0e-\x1f]')
+
+
+def _sanitize_xml_text(value: str) -> str:
+    """Sanitize a string for safe inclusion in XML.
+
+    1. Removes invalid XML 1.0 control characters
+    2. Escapes XML special characters (<, >, &, ", ')
+    """
+    # Remove invalid control characters
+    clean = _INVALID_XML_CHARS.sub('', value)
+    # Escape XML special characters
+    return xml_escape(clean, entities={'"': '&quot;', "'": '&apos;'})
+
+
 class Text(record): ...
 
 
@@ -150,7 +168,7 @@ def to_bytes(self) -> bytes:
         return bytes
 
     def __str__(self):
-        return self.value
+        return _sanitize_xml_text(self.value)
 
     @classmethod
     def parse(cls, fp) -> Self:
@@ -170,7 +188,7 @@ def to_bytes(self) -> bytes:
         return bytes
 
     def __str__(self):
-        return self.value
+        return _sanitize_xml_text(self.value)
 
     @classmethod
     def parse(cls, fp) -> Self:
@@ -190,7 +208,7 @@ def to_bytes(self) -> bytes:
         return bytes
 
     def __str__(self):
-        return self.value
+        return _sanitize_xml_text(self.value)
 
     @classmethod
     def parse(cls, fp) -> Self:
@@ -332,11 +350,7 @@ def __init__(self, value: str):
         self.value = value
 
     def __str__(self):
-        # TODO:  check if having unexcaped value is a problem?
-        # removed the return excape(self.value) because str() was used
-        # in the print_records function, so it printed stuff like
-        # amp(value) and stuff.
-        return self.value
+        return _sanitize_xml_text(self.value)
 
     def to_bytes(self) -> bytes:
         data = self.value.encode("utf-8")
@@ -360,7 +374,7 @@ def __init__(self, value: str):
         self.value = value
 
     def __str__(self):
-        return self.value
+        return _sanitize_xml_text(self.value)
 
     def to_bytes(self) -> bytes:
         data = self.value.encode("utf-8")
@@ -384,7 +398,7 @@ def __init__(self, value: str):
         self.value = value
 
     def __str__(self):
-        return self.value
+        return _sanitize_xml_text(self.value)
 
     def to_bytes(self) -> bytes:
         data = self.value.encode("utf-8")