FedAuth Cookie Not getting Created on Safari

Hi Guys,

Recently we encountered an issue in our sharepoint portal where FedAuth Cookie generated from SPFederationAuthenticationModule was not getting created on certain Safari browsers. After a long hours of testing , trials and error. We found that the issue was caused by SameSite property of the browser Cookie.

So in order to fix it, I applied the below code snippet, just after the SetPrincipalAndWriteSessionToken of the SPFederationAuthenticationModule.


fam.SetPrincipalAndWriteSessionToken(securityToken);
                            
string userAgent = Request.ServerVariables["HTTP_USER_AGENT"];

if ((userAgent.Contains("CPU iPhone OS") ||
                    userAgent.Contains("iPad; CPU OS") ||
                    userAgent.Contains("Macintosh; Intel Mac OS X")) &&
                userAgent.Contains("Safari"))
            {
                HttpCookie httpCookie = null;

                for (int i = 0; i < Response.Cookies.AllKeys.Count(); i++)
                {
                    httpCookie = Response.Cookies[Response.Cookies.AllKeys[i]];                   
                    httpCookie.SameSite = SameSiteMode.Lax;
                    
                } 
            }