[tbb-commits] [tor-browser/tor-browser-38.1.0esr-5.0-1] fixup! Bug 15646: Prevent keyboard layout fingerprinting in KeyboardEvent

[gk at torproject.org]

commit 9467a9d330a20b6850f7393185aec5d08e903df1
Author: Arthur Edelstein <arthuredelstein at gmail.com>
Date:   Fri Aug 7 18:18:04 2015 -0700

    fixup! Bug 15646: Prevent keyboard layout fingerprinting in KeyboardEvent
---
 dom/events/KeyCodeConsensus.h |   37 +++++++++++++++++++------------------
 dom/events/KeyboardEvent.cpp  |    5 +++--
 2 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/dom/events/KeyCodeConsensus.h b/dom/events/KeyCodeConsensus.h
index 53ec7f6..47d8341 100644
--- a/dom/events/KeyCodeConsensus.h
+++ b/dom/events/KeyCodeConsensus.h
@@ -9,9 +9,9 @@
 
 // KEY_INTERNAL is called by KEY or SHIFT.
 #define KEY_INTERNAL(key, code, keyCode, shift)                     \
-    gCodes->Put(NS_LITERAL_STRING(key), NS_LITERAL_STRING(#code));  \
-    gKeyCodes->Put(NS_LITERAL_STRING(key), keyCode);                \
-    gShiftStates->Put(NS_LITERAL_STRING(key), shift);
+  gCodes->Put(NS_LITERAL_STRING(key), NS_LITERAL_STRING(#code));    \
+  gKeyCodes->Put(NS_LITERAL_STRING(key), keyCode);                  \
+  gShiftStates->Put(NS_LITERAL_STRING(key), shift);
 
 // KEY and SHIFT assign a consensus codeName and keyCode for the given keyName.
 // KEY indicates that shift is off.
@@ -29,7 +29,7 @@ static nsDataHashtable<nsStringHashKey, bool>* gShiftStates;
 
 static StaticMutex createKeyCodesMutex;
 
-// Populate the global static maps gCodes, gKeCodes, gShiftStates
+// Populate the global static maps gCodes, gKeyCodes, gShiftStates
 // with their constant values.
 static void createKeyCodes()
 {
@@ -41,32 +41,33 @@ static void createKeyCodes()
   gKeyCodes = new nsDataHashtable<nsStringHashKey, uint32_t>();
   gShiftStates = new nsDataHashtable<nsStringHashKey, bool>();
 
-  KEY("AltLeft", AltLeft, 18)
-  KEY("AltRight", AltRight, 18)
+  KEY("Alt", AltLeft, 18)
+  KEY("ArrowDown", ArrowDown, 40)
+  KEY("ArrowLeft", ArrowLeft, 37)
+  KEY("ArrowRight", ArrowRight, 39)
+  KEY("ArrowUp", ArrowUp, 38)
+  KEY("Backspace", Backspace, 8)
   KEY("CapsLock", CapsLock, 20)
-  KEY("Control", ControlLeft, 17)
-  KEY("Meta", OSLeft, 91)
-  KEY("Shift", ShiftLeft, 16)
   KEY("ContextMenu", ContextMenu, 93)
-  KEY("Enter", Enter, 13)
-  KEY(" ", Space, 32)
-  KEY("Tab", Tab, 9)
+  KEY("Control", ControlLeft, 17)
   KEY("Delete", Delete, 46)
   KEY("End", End, 35)
+  KEY("Enter", Enter, 13)
+  KEY("Escape", Escape, 27)
   KEY("Help", Help, 6)
   KEY("Home", Home, 36)
   KEY("Insert", Insert, 45)
+  KEY("Meta", OSLeft, 91)
   KEY("PageDown", PageDown, 34)
   KEY("PageUp", PageUp, 33)
-  KEY("ArrowDown", ArrowDown, 40)
-  KEY("ArrowLeft", ArrowLeft, 37)
-  KEY("ArrowRight", ArrowRight, 39)
-  KEY("ArrowUp", ArrowUp, 38)
-  KEY("Escape", Escape, 27)
+  KEY("Pause", Pause, 19)
   KEY("PrintScreen", PrintScreen, 44)
   KEY("ScrollLock", ScrollLock, 145)
-  KEY("Pause", Pause, 19)
+  KEY("Shift", ShiftLeft, 16)
+  KEY("Tab", Tab, 9)
+  // Leaving "Clear" key unimplemented; it's inconsistent between platforms.
 
+  KEY(" ", Space, 32)
   KEY(",", Comma, 188)
   SHIFT("<", Comma, 188)
   KEY(".", Period, 190)
diff --git a/dom/events/KeyboardEvent.cpp b/dom/events/KeyboardEvent.cpp
index 6a68f96..19d4e73 100644
--- a/dom/events/KeyboardEvent.cpp
+++ b/dom/events/KeyboardEvent.cpp
@@ -50,8 +50,9 @@ KeyboardEvent::AltKey()
   if (ResistFingerprinting()) {
     nsString keyName;
     GetKey(keyName);
-    bool exists = gCodes->Get(keyName, nullptr);
-    return exists ? false : altState;
+    bool fakeShiftState;
+    gShiftStates->Get(keyName, &fakeShiftState);
+    return fakeShiftState ? false : altState;
   } else {
     return altState;
   }