Add signature.algorithm as config field in the SAML configuration

[Kristina Hoeppner]

The default SAML implementation only supports SHA1 at the moment. Some IDPs do not allow that anymore. Therefore, a SAML config would need to get a line added manually:

htdocs/auth/saml/config/config.php inside the config array, add
the following line

'signature.algorithm' =>
'http://www.w3.org/2001/04/xmldsig-more#rsa-sha256';

It would be better if that was more configurable directly on the front-end rather than in core code.

That field could be added to /admin/extensions/pluginconfig.php?plugintype=auth&pluginname=saml

[Kristina Hoeppner (kris-hoeppner)]

Francis is looking into this.

[Kristina Hoeppner (kris-hoeppner)]

In review: https://reviews.mahara.org/#/c/7878/

[Mahara Bot (dev-mahara)]

Reviewed: https://reviews.mahara.org/7878
Committed: https://git.mahara.org/mahara/mahara/commit/059b0765e4ce6867cccfda3c6b1d5426fe2c878d
Submitter: Robert Lyon (<email address hidden>)
Branch: master

commit 059b0765e4ce6867cccfda3c6b1d5426fe2c878d
Author: Francis Devine <email address hidden>
Date: Tue Jul 18 11:48:32 2017 +1200

Bug 1704887: Expose signing algorithm config to mahara

Allows you to set the signature algorithm for simplesamlphp from the
Mahara SAML plugin configuration screen.

The default setting is sha256, with sha1 available as a fallback for
those institutions who need it.

For an already existing site the default is set to sha1 as that is what
it would have been previously

behatnotneeded

Change-Id: I3eb628d837bdabbfc7641620e94fc2f127beceb9