expatreader.py 2.1 KB

12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061
  1. # defusedxml
  2. #
  3. # Copyright (c) 2013 by Christian Heimes <christian@python.org>
  4. # Licensed to PSF under a Contributor Agreement.
  5. # See https://www.python.org/psf/license for licensing details.
  6. """Defused xml.sax.expatreader
  7. """
  8. from __future__ import print_function, absolute_import
  9. from xml.sax.expatreader import ExpatParser as _ExpatParser
  10. from .common import DTDForbidden, EntitiesForbidden, ExternalReferenceForbidden
  11. __origin__ = "xml.sax.expatreader"
  12. class DefusedExpatParser(_ExpatParser):
  13. """Defused SAX driver for the pyexpat C module."""
  14. def __init__(
  15. self,
  16. namespaceHandling=0,
  17. bufsize=2 ** 16 - 20,
  18. forbid_dtd=False,
  19. forbid_entities=True,
  20. forbid_external=True,
  21. ):
  22. _ExpatParser.__init__(self, namespaceHandling, bufsize)
  23. self.forbid_dtd = forbid_dtd
  24. self.forbid_entities = forbid_entities
  25. self.forbid_external = forbid_external
  26. def defused_start_doctype_decl(self, name, sysid, pubid, has_internal_subset):
  27. raise DTDForbidden(name, sysid, pubid)
  28. def defused_entity_decl(
  29. self, name, is_parameter_entity, value, base, sysid, pubid, notation_name
  30. ):
  31. raise EntitiesForbidden(name, value, base, sysid, pubid, notation_name)
  32. def defused_unparsed_entity_decl(self, name, base, sysid, pubid, notation_name):
  33. # expat 1.2
  34. raise EntitiesForbidden(name, None, base, sysid, pubid, notation_name) # pragma: no cover
  35. def defused_external_entity_ref_handler(self, context, base, sysid, pubid):
  36. raise ExternalReferenceForbidden(context, base, sysid, pubid)
  37. def reset(self):
  38. _ExpatParser.reset(self)
  39. parser = self._parser
  40. if self.forbid_dtd:
  41. parser.StartDoctypeDeclHandler = self.defused_start_doctype_decl
  42. if self.forbid_entities:
  43. parser.EntityDeclHandler = self.defused_entity_decl
  44. parser.UnparsedEntityDeclHandler = self.defused_unparsed_entity_decl
  45. if self.forbid_external:
  46. parser.ExternalEntityRefHandler = self.defused_external_entity_ref_handler
  47. def create_parser(*args, **kwargs):
  48. return DefusedExpatParser(*args, **kwargs)