CSP improvements

[nijel]

2. CSP Improvements (for WebSite)

https://www.phpmyadmin.net/ return the following CSP header:
content-security-policy: default-src 'self'; script-src 'self' 'unsafe-inline' https://www.google-analytics.com/; img-src 'self' https://www.google-analytics.com/ https://www.paypalobjects.com/; style-src 'self' 'unsafe-inline'; child-src 'none'; object-src 'none'

2.1) Change Google Analytics loading

The usage of current Google Analytics code require unsafe-inline in script-src

fix: (by applying any of the below, the unsafe-inline can be removed from script-src)
move the inline code into external file
https://stackoverflow.com/questions/30939809/google-analytics-js-and-content-security-policy
or generate a hash for inline script:
https://www.w3.org/TR/2015/CR-CSP2-20150721/#script-src-hash-usage

2.2) Dynamic CSP usage

The https://www.paypalobjects.com/ in img-src is needed only in some pages, such as:

    https://github.com/phpmyadmin/website/blob/master/pmaweb/templates/donate.html#L31
    https://github.com/phpmyadmin/website/blob/master/pmaweb/templates/sponsors.html#L126

2.3) More Strict CSP Policy

The usage of action attribute is used in the below pages (to https://www.paypal.com/)

website/pmaweb/templates/donate.html

Line 22 in 92720e9

<form action="https://www.paypal.com/cgi-bin/webscr" method="post" target="_top">

website/pmaweb/templates/sponsors.html

Line 113 in 0da92e1

<form action="https://www.paypal.com/cgi-bin/webscr" method="post" target="_top">

thus use form-action directive to white-list action locations
https://developer.mozilla.org/en/docs/Web/Security/CSP/CSP_policy_directives#form-action

3. Missing CSP Policy

visiting:
https://www.phpmyadmin.net/fff/
result:

no CSP Policy sent, also the page load javascript from https://linkhelp.clients.google.com/ (need to add to script-src directive)
https://github.com/phpmyadmin/website/blob/master/pmaweb/templates/404.html#L23

[nijel]

2. CSP Violations Issues in WebSite

On Chrome:

Visiting:
https://www.phpmyadmin.net/downloads/

Result in Console:

Refused to load the image 'https://stats.g.doubleclick.net/r/collect?v=1&aip=1&t=dc&_r=3&tid=UA-2718724-14&cid=231898991.1468598139&jid=2067451453&_v=j44&z=2118007049' because it violates the following Content Security Policy directive: "img-src 'self' https://www.google-analytics.com/ https://www.paypalobjects.com/".

fix:
add https://stats.g.doubleclick.net to img-src directive.