Exception Value: Invalid input object: Element

[nick210]

Dear all,

I am trying to validate an xml signature (saml token) using signxml.
I am using the following code:

cert=open("/path_to_pem_file").read()
root=ElementTree.fromstring(saml_xml_token)
assertion_data=xmldsig(root)verify(x509_cert=cert)

And the last command xmldsig(root)verify(x509_cert=cert) gives me the following error: Invalid input object: Element

The full stack trace is the following:

Traceback:
File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py" in get_response

1.                 response = wrapped_callback(request, _callback_args, *_callback_kwargs)
   

   1.   assertion_data=xmldsig(root).verify()
      

      File "/usr/local/lib/python2.7/dist-packages/signxml/init.py" in verify

2.         _get_schema().assertValid(signature)
   

Exception Type: TypeError at /model_app/trySaml/
Exception Value: Invalid input object: Element

Do you have any idea what could be wrong with the code?

Thank you,
Nick

[kislyuk]

Can you please paste the actual full stack trace, with line numbers, etc.? You seem to have deleted a whole bunch of text from the stack trace. To format it, surround it with triple backtick quotes each on their own line: ```

[nick210]

Dear kislyul,

Thank you very much for your quick response and your help.

Please find below the stack trace with line numbers. Having searched the trace,this is all the information which is related to the signxml library. Anything else is django related, etc.

Traceback:
''' File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py" in get_response '''
''' 111. response = wrapped_callback(request, _callback_args, *_callback_kwargs) '''
''' File "django related file" in trySaml" '''
''' 225. assertion_data=xmldsig(root).verify() '''
''' File "/usr/local/lib/python2.7/dist-packages/signxml/init.py" in verify '''
''' 579. _get_schema().assertValid(signature) '''

Exception Type: TypeError at /model_app/trySaml/
Exception Value: Invalid input object: Element

I hope this will help :-)

Best regards,
Nikolaos Tousert

[kislyuk]

Please take a closer look at your message. I need the full stack trace down to the specific line where the error occurred, and including line numbers. Take a look at https://guides.github.com/features/mastering-markdown/ for help with how to format your message. You are not formatting it correctly, and as a result, the relevant information including line numbers is not being displayed.

[nick210]

Dear kislyuk,

I updated my previous comment with the line numbers.
Please let me know if it is now correct.

Thank you,
Nick

[nickcash]

For what it's worth, I also experienced this problem when using the stdlib xml.etree.ElementTree instead of the lxml version thereof, which is what I think @nick210 is experiencing. My use case is signing rather than verifying, but here's the code to recreate it:

import signxml,  xml.etree.ElementTree, lxml.etree

x = "<foo><bar></bar></foo>"
root1=xml.etree.ElementTree.fromstring(x)
root2=lxml.etree.fromstring(x)

>>> signxml.xmldsig(root1).sign(key=key, cert=cert)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/signxml/__init__.py", line 326, in sign
    self._get_payload_c14n(method, c14n_algorithm=c14n_algorithm)
  File "/usr/local/lib/python2.7/dist-packages/signxml/__init__.py", line 219, in _get_payload_c14n
    self.payload_c14n = self._c14n(self.payload, algorithm=c14n_algorithm)
  File "/usr/local/lib/python2.7/dist-packages/signxml/__init__.py", line 260, in _c14n
    inclusive_ns_prefixes=inclusive_ns_prefixes)
  File "lxml.etree.pyx", line 3201, in lxml.etree.tostring (src/lxml/lxml.etree.c:71561)
  File "serializer.pxi", line 164, in lxml.etree._tostringC14N (src/lxml/lxml.etree.c:119021)
  File "apihelpers.pxi", line 46, in lxml.etree._documentOrRaise (src/lxml/lxml.etree.c:14374)
TypeError: Invalid input object: Element
#Oh noes!

>>> signxml.xmldsig(root2).sign(key=key, cert=cert)
<Element foo at 0x7f7b7bbe7cb0>
#Everything went okay!

I think it can probably just be documented to use lxml.

[nickcash]

Interestingly in Python3.4, the same thing occurs but with a different (perhaps misleading) error message:

>>> signxml.xmldsig(root1).sign(key=key, cert=cert)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.4/dist-packages/signxml/__init__.py", line 326, in sign
    self._get_payload_c14n(method, c14n_algorithm=c14n_algorithm)
  File "/usr/local/lib/python3.4/dist-packages/signxml/__init__.py", line 200, in _get_payload_c14n
    self.payload.append(self.sig_root)
TypeError: must be xml.etree.ElementTree.Element, not lxml.etree._Element

[kislyuk]

Thank you for tracking this down, @nickcash. Fix released in v0.4.4. Please test.