--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -511,17 +511,17 @@ var gPopupBlockerObserver = {
     }
   },
 
   toggleAllowPopupsForSite: function(aEvent)
   {
     var pm = Services.perms;
     var shouldBlock = aEvent.target.getAttribute("block") == "true";
     var perm = shouldBlock ? pm.DENY_ACTION : pm.ALLOW_ACTION;
-    pm.add(gBrowser.currentURI, "popup", perm);
+    pm.addFromPrincipal(gBrowser.contentPrincipal, "popup", perm);
 
     if (!shouldBlock)
       this.showAllBlockedPopups(gBrowser.selectedBrowser);
 
     gBrowser.getNotificationBox().removeCurrentNotification();
   },
 
   fillPopupList: function(aEvent)
@@ -531,32 +531,32 @@ var gPopupBlockerObserver = {
     //          menuitems for the common subset of hosts present in the report, this will
     //          make us frame-safe.
     //
     // XXXjst - Note that when this is fixed to work with multi-framed sites,
     //          also back out the fix for bug 343772 where
     //          nsGlobalWindow::CheckOpenAllow() was changed to also
     //          check if the top window's location is whitelisted.
     let browser = gBrowser.selectedBrowser;
-    var uri = browser.currentURI;
+    var uri = browser.contentPrincipal.URI || browser.currentURI;
     var blockedPopupAllowSite = document.getElementById("blockedPopupAllowSite");
     try {
       blockedPopupAllowSite.removeAttribute("hidden");
-
+      let uriHost = uri.asciiHost ? uri.host : uri.spec;
       var pm = Services.perms;
       if (pm.testPermission(uri, "popup") == pm.ALLOW_ACTION) {
         // Offer an item to block popups for this site, if a whitelist entry exists
         // already for it.
-        let blockString = gNavigatorBundle.getFormattedString("popupBlock", [uri.host || uri.spec]);
+        let blockString = gNavigatorBundle.getFormattedString("popupBlock", [uriHost]);
         blockedPopupAllowSite.setAttribute("label", blockString);
         blockedPopupAllowSite.setAttribute("block", "true");
       }
       else {
         // Offer an item to allow popups for this site
-        let allowString = gNavigatorBundle.getFormattedString("popupAllow", [uri.host || uri.spec]);
+        let allowString = gNavigatorBundle.getFormattedString("popupAllow", [uriHost]);
         blockedPopupAllowSite.setAttribute("label", allowString);
         blockedPopupAllowSite.removeAttribute("block");
       }
     }
     catch (e) {
       blockedPopupAllowSite.setAttribute("hidden", "true");
     }
 
@@ -657,27 +657,40 @@ var gPopupBlockerObserver = {
         if (popups[i].popupWindowURIspec)
           aBrowser.unblockPopup(i);
       }
     }, null);
   },
 
   editPopupSettings: function()
   {
-    var host = "";
+    let prefillValue = "";
     try {
-      host = gBrowser.currentURI.host;
+      // We use contentPrincipal rather than currentURI to get the right
+      // value in case this is a data: URI that's inherited off something else.
+      // Some principals don't have URIs, so fall back in case URI is not present.
+      let principalURI = gBrowser.contentPrincipal.URI || gBrowser.currentURI;
+      if (principalURI) {
+        // asciiHost conveniently doesn't throw.
+        if (principalURI.asciiHost) {
+          prefillValue = principalURI.prePath;
+        } else {
+          // For host-less URIs like file://, prePath would effectively allow
+          // popups everywhere on file://. Use the full spec:
+          prefillValue = principalURI.spec;
+        }
+      }
     }
     catch (e) { }
 
     var bundlePreferences = document.getElementById("bundle_preferences");
     var params = { blockVisible   : false,
                    sessionVisible : false,
                    allowVisible   : true,
-                   prefilledHost  : host,
+                   prefilledHost  : prefillValue,
                    permissionType : "popup",
                    windowTitle    : bundlePreferences.getString("popuppermissionstitle"),
                    introText      : bundlePreferences.getString("popuppermissionstext") };
     var existingWindow = Services.wm.getMostRecentWindow("Browser:Permissions");
     if (existingWindow) {
       existingWindow.initWithParams(params);
       existingWindow.focus();
     }