Bug 583181 - Part 2: Add separate definitions for LEGACY_BUILD_ID and LEGACY_UA_GECKO_TRAIL. r=hsivonen

"Gecko trail" is the term used by MDN [1] for the YYYMMDD build date in the UA string's "Gecko/" token. Build ID is a YYYYMMDDHHMMSS build timestamp. Use LEGACY_BUILD_ID to spoof navigator.buildID. Use LEGACY_UA_GECKO_TRAIL to construct the UA string.

[1] https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/User-Agent/Firefox

Differential Revision: https://phabricator.services.mozilla.com/D7983

--HG--
extra : rebase_source : e2a4d7579d419046f0bad6290078f9a652a770d8
extra : source : 8a26c8598528722a8920513c7fdfea40aefe0dbc

dom/base/Navigator.cpp

@@ -456,8 +456,8 @@ Navigator::GetProduct(nsAString& aProduct)
 void
 Navigator::GetProductSub(nsAString& aProductSub)
 {
-  // Legacy build ID hardcoded for backward compatibility (bug 776376)
-  aProductSub.AssignLiteral(LEGACY_BUILD_ID);
+  // Legacy build date hardcoded for backward compatibility (bug 776376)
+  aProductSub.AssignLiteral(LEGACY_UA_GECKO_TRAIL);
 }
 
 nsMimeTypeArray*

dom/tests/mochitest/bugs/test_navigator_buildID.html

@@ -20,7 +20,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=583181
 
 SimpleTest.waitForExplicitFinish();
 
-const LEGACY_BUILD_ID = 20100101; // Resist Fingerprinting's build ID
+const LEGACY_BUILD_ID = 20181001000000;
 
 //
 // Access navigator.buildID from unprivileged web content.

netwerk/protocol/http/nsHttpHandler.cpp

@@ -516,7 +516,7 @@ nsHttpHandler::Init()
 #if defined(ANDROID)
     mProductSub.AssignLiteral(MOZILLA_UAVERSION);
 #else
-    mProductSub.AssignLiteral(LEGACY_BUILD_ID);
+    mProductSub.AssignLiteral(LEGACY_UA_GECKO_TRAIL);
 #endif
 
 #if DEBUG

toolkit/components/resistfingerprinting/nsRFPService.cpp

@@ -707,7 +707,7 @@ nsRFPService::GetSpoofedUserAgent(nsACString &userAgent)
   uint32_t spoofedVersion = firefoxVersion - ((firefoxVersion - 4) % 7);
   userAgent.Assign(nsPrintfCString(
     "Mozilla/5.0 (%s; rv:%d.0) Gecko/%s Firefox/%d.0",
-    SPOOFED_UA_OS, spoofedVersion, LEGACY_BUILD_ID, spoofedVersion));
+    SPOOFED_UA_OS, spoofedVersion, LEGACY_UA_GECKO_TRAIL, spoofedVersion));
 
   return rv;
 }

toolkit/components/resistfingerprinting/nsRFPService.h

@@ -46,7 +46,8 @@
 #endif
 
 #define SPOOFED_APPNAME    "Netscape"
-#define LEGACY_BUILD_ID    "20100101"
+#define LEGACY_BUILD_ID    "20181001000000"
+#define LEGACY_UA_GECKO_TRAIL "20100101"
 
 // Forward declare LRUCache, defined in nsRFPService.cpp
 class LRUCache;