I have a site that uses an SSO solution with another site. It does this by embedding an iFrame in the site for login.
The issue that I am having is that with Chrome and Safari, it does not save the login cookie when 3rd party cookies is disabled.
The site uses ASP.net. I have added the P3P header with a value of CP="CAO PSA OUR" in IIS. Its still not working. Does something else need to be done for Safari and Chrome?
P3P policies are not supported by most browsers barring Internet Explorer.
Per Wikipedia
Microsoft Internet Explorer is the only major browser to support P3P.
Google Chrome basically bypasses every OS dependent privacy settings (and by that I mean policies defined by IE for windows and Safari for Mac).
You can reach out to Chrome if you need more information about 3rd party cookies.
Safari - you're most likely out of luck. There are workarounds like Safari 3rd party cookie iframe trick no longer working? and Iframe, cross-domain cookies, p3p policy, and safari with error: A required anti-forgery token was not supplied or was invalid but your mileage may vary.
