CSP nonces are a feature available with CSP v2. Basically instead of saying "JS resources from the same domain are ok to be served" we now say "Ressources from everywhere are allowed as long as they add a `nonce` attribute to the script tag with the right nonce.
At the moment the nonce is basically just a `<?php p(base64_encode($_['requesttoken'])) ?>`, we have to decode the requesttoken since `:` is not an allowed value in the nonce. So if somebody does on their own include JS files (instead of using the `addScript` public API, they now must also include that attribute.)
IE does currently not implement CSP v2, thus there is a whitelist included that delivers the new CSP v2 policy to newer browsers. Check http://caniuse.com/#feat=contentsecuritypolicy2 for the current browser support list. An alternative approach would be to just add `'unsafe-inline'` as well as `'unsafe-inline'` is ignored by CSPv2 when a nonce is set. But this would make this security feature unusable at all in IE. Not worth it at the moment IMO.
Implementing this offers the following advantages:
1. **Security:** As we host resources from the same domain by design we don't have to worry about 'self' anymore being in the whitelist
2. **Performance:** We can move oc.js again to inline JS. This makes the loading way quicker as we don't have to load on every load of a new web page a blocking dynamically non-cached JavaScript file.
If you want to toy with CSP see also https://csp-evaluator.withgoogle.com/
Signed-off-by: Lukas Reschke <lukas@statuscode.ch>
In order to make it easier for a user/developer to replace logos in the core theme, I removed the hardcoded `logo.svg` and `logo-wide.svg` from the html, and replaced them with `div`s that use css background-image instead.
This has multiple advantages:
1. The user can now use any filename they want for the logo. They are no longer forced to use logo.svg or logo-wide.svg.
2. The user can now easily use a JPG, PNG or GIF logo instead of SVG (SVG's are awesome, but used by an unfortunately small percentage of web developers at the current time. Most probably don't even know how to make an SVG…).
3. The user doesn't have to resort to hacking the core theme template files in order to use a different filename or file type.
4. Greatly simplifies documentation instructions for how to change the logos (http://owncloud.org/theming/).
Signed-off-by: Jake Wilson <jakew@huebnerpetersen.com>
