From fab9adeccb22953ebc51781533a23e6974344e4d Mon Sep 17 00:00:00 2001
From: Bennett Cyphers <bennett@eff.org>
Date: Fri, 6 Apr 2018 17:43:28 -0700
Subject: [PATCH] Use upgradeToSecure when possible

Use Firefox's new upgradeToSecure flag instead of standard URI rewrites
when applying simple rulesets. Should fix issue with CORS blocking
certain HTTPS rewrites (#49).
---
 chromium/background-scripts/background.js | 23 +++++++++---
 chromium/background-scripts/util.js       | 45 +++++++++++++++++++++++
 2 files changed, 63 insertions(+), 5 deletions(-)

diff --git a/chromium/background-scripts/background.js b/chromium/background-scripts/background.js
index cbe1161e4b96..9d19dfb1c017 100644
--- a/chromium/background-scripts/background.js
+++ b/chromium/background-scripts/background.js
@@ -306,6 +306,8 @@ function onBeforeRequest(details) {
     return {cancel: shouldCancel};
   }
 
+  // if the request is for the main (top-level) frame of a tab, remove the
+  // ruleset for that tab
   if (details.type == "main_frame") {
     appliedRulesets.removeTab(details.tabId);
   }
@@ -320,12 +322,21 @@ function onBeforeRequest(details) {
     return {cancel: shouldCancel};
   }
 
+  // whether to use mozilla's upgradeToSecure BlockingResponse if available
+  var upgradeToSecure = false;
   var newuristr = null;
+  // check rewritten URIs against the trivially upgraded URI
+  var trivialUpgradeUri = canonical_url.replace(rules.trivial_rule_from_c,
+                                                rules.trivial_rule_to);
 
   for (let ruleset of potentiallyApplicable) {
     appliedRulesets.addRulesetToTab(details.tabId, details.type, ruleset);
     if (ruleset.active && !newuristr) {
       newuristr = ruleset.apply(canonical_url);
+      // for now, only upgradeToSecure for trivial rulesets
+      if (newuristr == trivialUpgradeUri) {
+        upgradeToSecure = true;
+      }
     }
   }
 
@@ -358,19 +369,21 @@ function onBeforeRequest(details) {
     // If loading a main frame, try the HTTPS version as an alternative to
     // failing.
     if (shouldCancel) {
+      upgradeToSecure = true;
       if (!newuristr) {
-        return {redirectUrl: canonical_url.replace(/^http:/, "https:")};
+        newuristr = canonical_url.replace(/^http:/, "https:");
       } else {
-        return {redirectUrl: newuristr.replace(/^http:/, "https:")};
+        newuristr = newuristr.replace(/^http:/, "https:");
       }
-    }
-    if (newuristr && newuristr.substring(0, 5) === "http:") {
+    } else if (newuristr && newuristr.substring(0, 5) === "http:") {
       // Abort early if we're about to redirect to HTTP in HTTP Nowhere mode
       return {cancel: true};
     }
   }
 
-  if (newuristr) {
+  if (upgradeToSecure && getBrowserInfo().name == 'Firefox' && getBrowserInfo().version >= 59) {
+    return {upgradeToSecure: true};
+  } else if (newuristr) {
     return {redirectUrl: newuristr};
   } else {
     return {cancel: shouldCancel};
diff --git a/chromium/background-scripts/util.js b/chromium/background-scripts/util.js
index 9d7dfc98bde3..001cb0edd08a 100644
--- a/chromium/background-scripts/util.js
+++ b/chromium/background-scripts/util.js
@@ -106,3 +106,48 @@ Object.assign(exports, {
 });
 
 })(typeof exports == 'undefined' ? require.scopes.util = {} : exports);
+
+// from
+// https://www.gregoryvarghese.com/how-to-get-browser-name-and-version-via-javascript/
+function getBrowserInfo() {
+  var agent = navigator.userAgent,
+    match = agent.match(/(opera|chrome|safari|firefox|msie|trident(?=\/))\/?\s*(\d+)/i);
+
+  if (!match) {
+    return {
+      name: null,
+      version: null
+    };
+  }
+
+  var name = match[1],
+    version = match[2];
+
+  if (/trident/i.test(name)) {
+    var ieMatch = /\brv[ :]+(\d+)/g.exec(agent) || []; 
+    return {
+      name: 'IE ', 
+      version: (ieMatch[1] || '')
+    };
+  }   
+
+  if (name === 'Chrome') {
+    var opMatch = agent.match(/\bOPR\/(\d+)/);
+    if (tem != null) {
+      return {
+        name: 'Opera', 
+        version: match[1]
+      };
+    }
+  }   
+
+  var vMatch = agent.match(/version\/(\d+)/i);
+  if (vMatch != null) {
+    version = vMatch[1];
+  }
+
+  return {
+    name: name,
+    version: version
+  };
+}