--- a/netwerk/base/nsNetUtil.h
+++ b/netwerk/base/nsNetUtil.h
@@ -645,18 +645,18 @@ bool NS_GetOriginAttributes(nsIChannel *
 bool NS_HasBeenCrossOrigin(nsIChannel* aChannel, bool aReport = false);
 
 // Constants duplicated from nsIScriptSecurityManager so we avoid having necko
 // know about script security manager.
 #define NECKO_NO_APP_ID 0
 #define NECKO_UNKNOWN_APP_ID UINT32_MAX
 
 // Unique first-party domain for separating the safebrowsing cookie.
-// Note if this value is changed, code in test_cookiejars_safebrowsing.js
-// should also be changed.
+// Note if this value is changed, code in test_cookiejars_safebrowsing.js and
+// nsUrlClassifierHashCompleter.js should also be changed.
 #define NECKO_SAFEBROWSING_FIRST_PARTY_DOMAIN \
   "safebrowsing.86868755-6b82-4842-b301-72671a0db32e.mozilla"
 
 // Unique first-party domain for separating about uri.
 #define ABOUT_URI_FIRST_PARTY_DOMAIN \
   "about.ef2a7dd5-93bc-417f-a698-142c3116864f.mozilla"
 
 /**

--- a/netwerk/test/unit/test_cookiejars_safebrowsing.js
+++ b/netwerk/test/unit/test_cookiejars_safebrowsing.js
@@ -33,16 +33,17 @@ XPCOMUtils.defineLazyGetter(this, "URL",
 });
 
 XPCOMUtils.defineLazyModuleGetter(this, "SafeBrowsing",
   "resource://gre/modules/SafeBrowsing.jsm");
 
 var setCookiePath = "/setcookie";
 var checkCookiePath = "/checkcookie";
 var safebrowsingUpdatePath = "/safebrowsingUpdate";
+var safebrowsingGethashPath = "/safebrowsingGethash";
 var httpserver;
 
 function inChildProcess() {
   return Cc["@mozilla.org/xre/app-info;1"].getService(Ci.nsIXULRuntime)
            .processType != Ci.nsIXULRuntime.PROCESS_TYPE_DEFAULT;
 }
 
 function cookieSetHandler(metadata, response) {
@@ -64,16 +65,26 @@ function cookieCheckHandler(metadata, re
 function safebrowsingUpdateHandler(metadata, response) {
   var cookieName = "sb-update-cookie";
   response.setStatusLine(metadata.httpVersion, 200, "Ok");
   response.setHeader("set-Cookie", cookieName + "=1; Path=/", false);
   response.setHeader("Content-Type", "text/plain");
   response.bodyOutputStream.write("Ok", "Ok".length);
 }
 
+function safebrowsingGethashHandler(metadata, response) {
+  var cookieName = "sb-gethash-cookie";
+  response.setStatusLine(metadata.httpVersion, 200, "Ok");
+  response.setHeader("set-Cookie", cookieName + "=1; Path=/", false);
+  response.setHeader("Content-Type", "text/plain");
+
+  let msg = "test-phish-simplea:1:32\n" + "a".repeat(32);
+  response.bodyOutputStream.write(msg, msg.length);
+}
+
 function setupChannel(path, originAttributes) {
   var channel = NetUtil.newChannel({uri: URL + path, loadUsingSystemPrincipal: true});
   channel.loadInfo.originAttributes = originAttributes;
   channel.QueryInterface(Ci.nsIHttpChannel);
   return channel;
 }
 
 function run_test() {
@@ -84,16 +95,17 @@ function run_test() {
   // Allow all cookies if the pref service is available in this process.
   if (!inChildProcess())
     Services.prefs.setIntPref("network.cookie.cookieBehavior", 0);
 
   httpserver = new HttpServer();
   httpserver.registerPathHandler(setCookiePath, cookieSetHandler);
   httpserver.registerPathHandler(checkCookiePath, cookieCheckHandler);
   httpserver.registerPathHandler(safebrowsingUpdatePath, safebrowsingUpdateHandler);
+  httpserver.registerPathHandler(safebrowsingGethashPath, safebrowsingGethashHandler);
 
   httpserver.start(-1);
   run_next_test();
 }
 
 // this test does not emulate a response in the body,
 // rather we only set the cookies in the header of response.
 add_test(function test_safebrowsing_update() {
@@ -112,16 +124,33 @@ add_test(function test_safebrowsing_upda
   function onDownloadError() {
     do_throw("ERROR: received onDownloadError!");
   }
 
   streamUpdater.downloadUpdates("test-phish-simple,test-malware-simple", "",
     true, URL + safebrowsingUpdatePath, onSuccess, onUpdateError, onDownloadError);
 });
 
+add_test(function test_safebrowsing_gethash() {
+  var hashCompleter = Cc["@mozilla.org/url-classifier/hashcompleter;1"]
+                      .getService(Ci.nsIUrlClassifierHashCompleter);
+
+  hashCompleter.complete("aaaa",
+                         URL + safebrowsingGethashPath,
+                         "test-phish-simple", {
+    completionV2(hash, table, chunkId) {
+    },
+
+    completionFinished(status) {
+      do_check_eq(status, Cr.NS_OK);
+      run_next_test();
+    },
+  });
+});
+
 add_test(function test_non_safebrowsing_cookie() {
 
   var cookieName = 'regCookie_id0';
   var originAttributes = new OriginAttributes(0, false, 0);
 
   function setNonSafeBrowsingCookie() {
     var channel = setupChannel(setCookiePath, originAttributes);
     channel.setRequestHeader("set-cookie", cookieName, false);
@@ -161,18 +190,20 @@ add_test(function test_safebrowsing_cook
   function checkSafeBrowsingCookie() {
     var channel = setupChannel(checkCookiePath, originAttributes);
     channel.asyncOpen2(new ChannelListener(completeCheckSafeBrowsingCookie, null));
   }
 
   function completeCheckSafeBrowsingCookie(request, data, context) {
     // Confirm that all >> THREE << cookies are sent back over the channel:
     //   a) the safebrowsing cookie set when updating
-    //   b) the regular cookie with custom loadcontext defined in this test.
+    //   b) the safebrowsing cookie set when sending gethash
+    //   c) the regular cookie with custom loadcontext defined in this test.
     var expectedCookies = "sb-update-cookie=1; ";
+    expectedCookies += "sb-gethash-cookie=1; ";
     expectedCookies += cookieName + "=1";
     request.QueryInterface(Ci.nsIHttpChannel);
     var cookiesSeen = request.getResponseHeader("saw-cookies");
 
     do_check_eq(cookiesSeen, expectedCookies);
     httpserver.stop(do_test_finished);
   }
 

--- a/toolkit/components/url-classifier/nsUrlClassifierHashCompleter.js
+++ b/toolkit/components/url-classifier/nsUrlClassifierHashCompleter.js
@@ -427,16 +427,21 @@ HashCompleterRequest.prototype = {
 
     log("actualGethashUrl: " + actualGethashUrl);
 
     let channel = NetUtil.newChannel({
       uri: actualGethashUrl,
       loadUsingSystemPrincipal: true
     });
     channel.loadFlags = loadFlags;
+    channel.loadInfo.originAttributes = {
+      // The firstPartyDomain value should sync with NECKO_SAFEBROWSING_FIRST_PARTY_DOMAIN
+      // defined in nsNetUtil.h.
+      firstPartyDomain: "safebrowsing.86868755-6b82-4842-b301-72671a0db32e.mozilla"
+    };
 
     // Disable keepalive.
     let httpChannel = channel.QueryInterface(Ci.nsIHttpChannel);
     httpChannel.setRequestHeader("Connection", "close", false);
 
     this._channel = channel;
 
     if (this.isV4) {