[tor-commits] [tor-browser/tor-browser-91.2.0esr-11.0-1] Bug 30541: Disable WebGL readPixel() for web content

[sysrqb at torproject.org]

commit a37bdcbb5672dc8fd5ee25ee9b2f9c871cfa3c9b
Author: Georg Koppen <gk at torproject.org>
Date:   Wed May 29 12:29:19 2019 +0000

    Bug 30541: Disable WebGL readPixel() for web content
---
 dom/canvas/ClientWebGLContext.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/dom/canvas/ClientWebGLContext.cpp b/dom/canvas/ClientWebGLContext.cpp
index 05dcb79a230e..c9875e62c8af 100644
--- a/dom/canvas/ClientWebGLContext.cpp
+++ b/dom/canvas/ClientWebGLContext.cpp
@@ -4636,6 +4636,14 @@ bool ClientWebGLContext::ReadPixels_SharedPrecheck(
     return false;
   }
 
+  // Security check passed, but don't let content readPixel calls through for
+  // now, if Resist Fingerprinting Mode is enabled.
+  if (nsContentUtils::ResistFingerprinting(aCallerType)) {
+    JsWarning("readPixels: Not allowed in Resist Fingerprinting Mode");
+    out_error.Throw(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
+    return false;
+  }
+
   return true;
 }