Ignore attribute with no attributeValue child

[T1B0]

A childless attribute (without attributeValue child node) like :

  <AttributeStatement>
    <Attribute Name="fubar.roles"/>
  ....
 </AttributeStatement>

would cause a typeError in saml.js#L582. this fix would ignore such attribute

[T1B0]

Also please note that this is a quick-fix, according to SAML specs the attributeValue is defined as

<element name="Attribute" type="saml:AttributeType"/>
<complexType name="AttributeType">
  <complexContent>
    <extension base="saml:AttributeDesignatorType">
      <sequence>
        <element ref="saml:AttributeValue" maxOccurs="unbounded"/>
      </sequence>
    </extension>
  </complexContent>
</complexType>

and since the element is inside a "sequence", the minOccurs default value is 1, so the attributeValue is suposed to appears at least once for any attribute tag.
I don't know if you'd rather throw an error than just ignore a malformed attribute, i guess it depends on how strict you intend this lib to be.

[ploer]

Thanks for the PR! If it's something you've actually run into from a real IDP, then I'd definitely like to tolerate it.

Can you add a test case for this?

[T1B0]

just added a test case. and yes I actually run into this from a customer's private IDP, I've asked on which SAML lib they're based but didn't get an answer yet - i'll let you know if I find out

edit:
Just heard back from this customer, they uses a commercial provider called "sign&go" by ilex => http://www.ilex-international.com/en/our-products/signgo/ . so this is a legit, live use case I guess.

[T1B0]

had some feedback from an ilex developer, he pointed out that in SAML2.0 the attributeValue has become optional :

2.7.3.1 Element
The element identifies an attribute by name and optionally includes its value(s). It has the
AttributeType complex type. It is used within an attribute statement to express particular attributes ...

the xml-schema I quoted earlier was from SAML1.1 specs, where attributeValue were to occurs 1 or more per attribute

[ploer]

Thanks!