tor-browser

commit 05e11564b0f449829262ded7f2fc2809eb3dc5ce
parent 2a597f21c28345e274cc9ace5e52d73539a7fb9c
Author: Tom Ritter <tom@mozilla.com>
Date:   Fri, 19 Dec 2025 14:47:59 +0000

Bug 2005273: Add sources and combinations we know occur in the wild r=timhuang

Differential Revision: https://phabricator.services.mozilla.com/D276878

Diffstat:
M
toolkit/components/antitracking/metrics.yaml
 | 
9
++++++---
M
toolkit/components/resistfingerprinting/nsRFPService.cpp
 | 
18
++++++++++++++----
M
toolkit/components/resistfingerprinting/nsRFPService.h
 | 
6
++++++

3 files changed, 26 insertions(+), 7 deletions(-)
diff --git a/toolkit/components/antitracking/metrics.yaml b/toolkit/components/antitracking/metrics.yaml
@@ -174,7 +174,10 @@ contentblocking:
                 # 2^33 - 2^40
                 "8589934592", "17179869184", "34359738368", "68719476736", "137438953472", "274877906944", "549755813888", "1099511627776",
                 # Known Combinations
-                "80", "144", "208", "8388736"
+                "17", "65", "80", "81", "96", "144", "145", "192", "208", "209", "241", "1040", "1041", "1088", "1104", "1152", "1168",
+                "1169", "1216", "1232", "1233", "1265", "8388624", "8388688", "8388736", "8388752", "8388816", "2147483649", "2147483665",
+                "2147483712", "2147483713", "2147483793", "4294967297", "4294967312", "4294967328", "4294967360", "4294967361", "4294967376",
+                "4294967424", "4294967440", "4294967504", "4294968384", "4294968400", "4294968529", "36507222016", "40802189312"
                 ]
     bugs:
       - https://bugzilla.mozilla.org/show_bug.cgi?id=1873716
@@ -214,9 +217,9 @@ contentblocking:
                 "80", "144", "208", "8388736"
                 ]
     bugs:
-      - https://bugzilla.mozilla.org/show_bug.cgi?id=
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1873716
     data_reviews:
-      - https://bugzilla.mozilla.org/show_bug.cgi?id=
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1847990
     notification_emails:
       - seceng-telemetry@mozilla.com
     expires: 165
diff --git a/toolkit/components/resistfingerprinting/nsRFPService.cpp b/toolkit/components/resistfingerprinting/nsRFPService.cpp
@@ -2211,6 +2211,20 @@ CanvasUsageSource CanvasUsage::GetCanvasUsageSource(
             logImpossible("Unknown API for Canvas2D");
             return CanvasUsageSource::Impossible;
         }
+      case dom::CanvasContextType::OffscreenCanvas2D:
+        // Very confused about how we get an OffscreenCanvas2D context without
+        // an OffscreenCanvas but it does happen in the wild...
+        switch (api) {
+          case CanvasExtractionAPI::GetImageData:
+            return CanvasUsageSource::
+                MainThread_Canvas_OffscreenCanvas2D_getImageData;
+          case CanvasExtractionAPI::ToBlob:
+            return CanvasUsageSource::
+                MainThread_Canvas_OffscreenCanvas2D_toBlob;
+          default:
+            logImpossible("Unsupported API for OffscreenCanvas2D");
+            return CanvasUsageSource::Impossible;
+        }
       case dom::CanvasContextType::WebGL1:
       case dom::CanvasContextType::WebGL2:
         switch (api) {
@@ -2286,10 +2300,6 @@ CanvasUsageSource CanvasUsage::GetCanvasUsageSource(
           return CanvasUsageSource::Impossible;
       }
     case dom::CanvasContextType::OffscreenCanvas2D:
-      if (isMainThread) {
-        logImpossible("OffscreenCanvas2D on main thread");
-        return CanvasUsageSource::Impossible;
-      }
       switch (api) {
         case CanvasExtractionAPI::GetImageData:
           return Worker_OffscreenCanvasCanvas2D_Canvas2D_getImageData;
diff --git a/toolkit/components/resistfingerprinting/nsRFPService.h b/toolkit/components/resistfingerprinting/nsRFPService.h
@@ -305,6 +305,12 @@ enum CanvasUsageSource : uint64_t {
   Worker_OffscreenCanvas_WebGPU_toBlob = 1llu << 36,
   Worker_OffscreenCanvas_WebGPU_getImageData = 1llu << 37,
 
+  // --- New entires added here to preserve original values (no reordering!)
+  MainThread_Canvas_OffscreenCanvas2D_getImageData = 1llu << 38,
+  MainThread_Canvas_OffscreenCanvas2D_toBlob = 1llu << 39,
+
+  // After you go past 40 - metrics.yaml will need to be updated
+
 };
 MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(CanvasUsageSource);
 nsCString CanvasUsageSourceToString(CanvasUsageSource aSource);