Scenario is from JENKINS-34135.

Steps
1. Remove read permission for anonymous user in Jenkins
2. Go to Jenkins root URL

Expected behaviour
User should be redirected to http://localhost:8080/login?from=%2F

curl output

< HTTP/1.1 403 Forbidden
< X-Content-Type-Options: nosniff
< Set-Cookie: JSESSIONID.669c603d=dn8skvjnwdyn16yo43rrc12iq;Path=/;HttpOnly
< Expires: Thu, 01 Jan 1970 00:00:00 GMT
< Content-Type: text/html;charset=UTF-8
< X-Hudson: 1.395
< X-Jenkins: 1.642.4
< X-Jenkins-Session: 4564a514
< X-Hudson-CLI-Port: 60777
< X-Jenkins-CLI-Port: 60777
< X-Jenkins-CLI2-Port: 60777
< X-You-Are-Authenticated-As: anonymous
< X-You-Are-In-Group:
< X-Required-Permission: hudson.model.Hudson.Read
< X-Permission-Implied-By: hudson.security.Permission.GenericRead
< X-Permission-Implied-By: hudson.model.Hudson.Administer
< Content-Length: 793

Current behaviour
User gets blank page

curl output

< HTTP/1.1 200 OK
< Stapler-Trace-001: -> evaluate(<hudson.model.Hudson@3ecbc929> :hudson.model.Hudson,"")
< Stapler-Trace-002: -> evaluate(((StaplerProxy)<hudson.model.Hudson@3ecbc929>).getTarget(),"")
< Content-Length: 0
< Server: Jetty(8.y.z-SNAPSHOT)