Add setting to disable BASIC authentication (#8586)

Closes #8561.

docs/content/doc/advanced/config-cheat-sheet.en-us.md

@@ -265,6 +265,10 @@ Values containing `#` or `;` must be quoted using `` ` `` or `"""`.
 - `REQUIRE_SIGNIN_VIEW`: **false**: Enable this to force users to log in to view any page.
 - `ENABLE_NOTIFY_MAIL`: **false**: Enable this to send e-mail to watchers of a repository when
    something happens, like creating issues. Requires `Mailer` to be enabled.
+- `ENABLE_BASIC_AUTHENTICATION`: **true**: Disable this to disallow authenticaton using HTTP
+   BASIC and the user's password. Please note if you disable this you will not be able to access the
+   tokens API endpoints using a password. Further, this only disables BASIC authentication using the
+   password - not tokens or OAuth Basic.
 - `ENABLE_REVERSE_PROXY_AUTHENTICATION`: **false**: Enable this to allow reverse proxy authentication.
 - `ENABLE_REVERSE_PROXY_AUTO_REGISTRATION`: **false**: Enable this to allow auto-registration
    for reverse authentication.

modules/auth/auth.go

@@ -224,6 +224,9 @@ func SignedInUser(ctx *macaron.Context, sess session.Store) (*models.User, bool)
 			}
 
 			if u == nil {
+				if !setting.Service.EnableBasicAuth {
+					return nil, false
+				}
 				u, err = models.UserSignIn(uname, passwd)
 				if err != nil {
 					if !models.IsErrUserNotExist(err) {

modules/setting/service.go

@@ -23,6 +23,7 @@ var Service struct {
 	ShowRegistrationButton                  bool
 	RequireSignInView                       bool
 	EnableNotifyMail                        bool
+	EnableBasicAuth                         bool
 	EnableReverseProxyAuth                  bool
 	EnableReverseProxyAutoRegister          bool
 	EnableReverseProxyEmail                 bool
@@ -60,6 +61,7 @@ func newService() {
 	Service.EmailDomainWhitelist = sec.Key("EMAIL_DOMAIN_WHITELIST").Strings(",")
 	Service.ShowRegistrationButton = sec.Key("SHOW_REGISTRATION_BUTTON").MustBool(!(Service.DisableRegistration || Service.AllowOnlyExternalRegistration))
 	Service.RequireSignInView = sec.Key("REQUIRE_SIGNIN_VIEW").MustBool()
+	Service.EnableBasicAuth = sec.Key("ENABLE_BASIC_AUTHENTICATION").MustBool(true)
 	Service.EnableReverseProxyAuth = sec.Key("ENABLE_REVERSE_PROXY_AUTHENTICATION").MustBool()
 	Service.EnableReverseProxyAutoRegister = sec.Key("ENABLE_REVERSE_PROXY_AUTO_REGISTRATION").MustBool()
 	Service.EnableReverseProxyEmail = sec.Key("ENABLE_REVERSE_PROXY_EMAIL").MustBool()