InputTracer: Distinguish sensitive events

There are three levels of tracing: complete, redacted, and none.

Write events that are redacted into a separate proto, while also
omitting certain fields from being written.

The redacted level will be used in subsequent CLs.

Bug: 210460522
Test: manual with perfetto
Change-Id: Ie65e7915c3aa5fc972e675c43e46970363bab3a4
diff --git a/services/inputflinger/dispatcher/trace/AndroidInputEventProtoConverter.cpp b/services/inputflinger/dispatcher/trace/AndroidInputEventProtoConverter.cpp
index ddc4cb3..c431fb7 100644
--- a/services/inputflinger/dispatcher/trace/AndroidInputEventProtoConverter.cpp
+++ b/services/inputflinger/dispatcher/trace/AndroidInputEventProtoConverter.cpp
@@ -39,7 +39,8 @@
 } // namespace
 
 void AndroidInputEventProtoConverter::toProtoMotionEvent(const TracedMotionEvent& event,
-                                                         proto::AndroidMotionEvent& outProto) {
+                                                         proto::AndroidMotionEvent& outProto,
+                                                         bool isRedacted) {
     outProto.set_event_id(event.id);
     outProto.set_event_time_nanos(event.eventTime);
     outProto.set_down_time_nanos(event.downTime);
@@ -48,11 +49,15 @@
     outProto.set_device_id(event.deviceId);
     outProto.set_display_id(event.displayId);
     outProto.set_classification(static_cast<int32_t>(event.classification));
-    outProto.set_cursor_position_x(event.xCursorPosition);
-    outProto.set_cursor_position_y(event.yCursorPosition);
     outProto.set_flags(event.flags);
     outProto.set_policy_flags(event.policyFlags);
 
+    if (!isRedacted) {
+        outProto.set_cursor_position_x(event.xCursorPosition);
+        outProto.set_cursor_position_y(event.yCursorPosition);
+        outProto.set_meta_state(event.metaState);
+    }
+
     for (uint32_t i = 0; i < event.pointerProperties.size(); i++) {
         auto* pointer = outProto.add_pointer();
 
@@ -66,13 +71,17 @@
             const auto axis = bits.clearFirstMarkedBit();
             auto axisEntry = pointer->add_axis_value();
             axisEntry->set_axis(axis);
-            axisEntry->set_value(coords.values[axisIndex]);
+
+            if (!isRedacted) {
+                axisEntry->set_value(coords.values[axisIndex]);
+            }
         }
     }
 }
 
 void AndroidInputEventProtoConverter::toProtoKeyEvent(const TracedKeyEvent& event,
-                                                      proto::AndroidKeyEvent& outProto) {
+                                                      proto::AndroidKeyEvent& outProto,
+                                                      bool isRedacted) {
     outProto.set_event_id(event.id);
     outProto.set_event_time_nanos(event.eventTime);
     outProto.set_down_time_nanos(event.downTime);
@@ -80,21 +89,28 @@
     outProto.set_action(event.action);
     outProto.set_device_id(event.deviceId);
     outProto.set_display_id(event.displayId);
-    outProto.set_key_code(event.keyCode);
-    outProto.set_scan_code(event.scanCode);
-    outProto.set_meta_state(event.metaState);
     outProto.set_repeat_count(event.repeatCount);
     outProto.set_flags(event.flags);
     outProto.set_policy_flags(event.policyFlags);
+
+    if (!isRedacted) {
+        outProto.set_key_code(event.keyCode);
+        outProto.set_scan_code(event.scanCode);
+        outProto.set_meta_state(event.metaState);
+    }
 }
 
 void AndroidInputEventProtoConverter::toProtoWindowDispatchEvent(
-        const WindowDispatchArgs& args, proto::AndroidWindowInputDispatchEvent& outProto) {
+        const WindowDispatchArgs& args, proto::AndroidWindowInputDispatchEvent& outProto,
+        bool isRedacted) {
     std::visit([&](auto entry) { outProto.set_event_id(entry.id); }, args.eventEntry);
     outProto.set_vsync_id(args.vsyncId);
     outProto.set_window_id(args.windowId);
     outProto.set_resolved_flags(args.resolvedFlags);
 
+    if (isRedacted) {
+        return;
+    }
     if (auto* motion = std::get_if<TracedMotionEvent>(&args.eventEntry); motion != nullptr) {
         for (size_t i = 0; i < motion->pointerProperties.size(); i++) {
             auto* pointerProto = outProto.add_dispatched_pointer();
diff --git a/services/inputflinger/dispatcher/trace/AndroidInputEventProtoConverter.h b/services/inputflinger/dispatcher/trace/AndroidInputEventProtoConverter.h
index bab1701..887913f 100644
--- a/services/inputflinger/dispatcher/trace/AndroidInputEventProtoConverter.h
+++ b/services/inputflinger/dispatcher/trace/AndroidInputEventProtoConverter.h
@@ -32,10 +32,12 @@
 class AndroidInputEventProtoConverter {
 public:
     static void toProtoMotionEvent(const TracedMotionEvent& event,
-                                   proto::AndroidMotionEvent& outProto);
-    static void toProtoKeyEvent(const TracedKeyEvent& event, proto::AndroidKeyEvent& outProto);
+                                   proto::AndroidMotionEvent& outProto, bool isRedacted);
+    static void toProtoKeyEvent(const TracedKeyEvent& event, proto::AndroidKeyEvent& outProto,
+                                bool isRedacted);
     static void toProtoWindowDispatchEvent(const WindowDispatchArgs&,
-                                           proto::AndroidWindowInputDispatchEvent& outProto);
+                                           proto::AndroidWindowInputDispatchEvent& outProto,
+                                           bool isRedacted);
 
     static impl::TraceConfig parseConfig(proto::AndroidInputEventConfig::Decoder& protoConfig);
 };
diff --git a/services/inputflinger/dispatcher/trace/InputTracingPerfettoBackend.cpp b/services/inputflinger/dispatcher/trace/InputTracingPerfettoBackend.cpp
index 998ec8a..bed753c 100644
--- a/services/inputflinger/dispatcher/trace/InputTracingPerfettoBackend.cpp
+++ b/services/inputflinger/dispatcher/trace/InputTracingPerfettoBackend.cpp
@@ -69,6 +69,30 @@
     return false;
 }
 
+TraceLevel PerfettoBackend::InputEventDataSource::resolveTraceLevel(
+        const TracedEventArgs& args) const {
+    // Check for matches with the rules in the order that they are defined.
+    for (const auto& rule : mConfig.rules) {
+        if (ruleMatches(rule, args)) {
+            return rule.level;
+        }
+    }
+
+    // The event is not traced if it matched zero rules.
+    return TraceLevel::TRACE_LEVEL_NONE;
+}
+
+bool PerfettoBackend::InputEventDataSource::ruleMatches(const TraceRule& rule,
+                                                        const TracedEventArgs& args) const {
+    // By default, a rule will match all events. Return early if the rule does not match.
+
+    if (rule.matchSecure.has_value() && *rule.matchSecure != args.isSecure) {
+        return false;
+    }
+
+    return true;
+}
+
 // --- PerfettoBackend ---
 
 std::once_flag PerfettoBackend::sDataSourceRegistrationFlag{};
@@ -94,54 +118,62 @@
 
 void PerfettoBackend::traceMotionEvent(const TracedMotionEvent& event,
                                        const TracedEventArgs& args) {
-    if (args.isSecure) {
-        // For now, avoid tracing secure event entirely.
-        return;
-    }
     InputEventDataSource::Trace([&](InputEventDataSource::TraceContext ctx) {
         auto dataSource = ctx.GetDataSourceLocked();
         if (dataSource->shouldIgnoreTracedInputEvent(event.eventType)) {
             return;
         }
+        const TraceLevel traceLevel = dataSource->resolveTraceLevel(args);
+        if (traceLevel == TraceLevel::TRACE_LEVEL_NONE) {
+            return;
+        }
+        const bool isRedacted = traceLevel == TraceLevel::TRACE_LEVEL_REDACTED;
         auto tracePacket = ctx.NewTracePacket();
         auto* inputEvent = tracePacket->set_android_input_event();
-        auto* dispatchMotion = inputEvent->set_dispatcher_motion_event();
-        AndroidInputEventProtoConverter::toProtoMotionEvent(event, *dispatchMotion);
+        auto* dispatchMotion = isRedacted ? inputEvent->set_dispatcher_motion_event_redacted()
+                                          : inputEvent->set_dispatcher_motion_event();
+        AndroidInputEventProtoConverter::toProtoMotionEvent(event, *dispatchMotion, isRedacted);
     });
 }
 
 void PerfettoBackend::traceKeyEvent(const TracedKeyEvent& event, const TracedEventArgs& args) {
-    if (args.isSecure) {
-        // For now, avoid tracing secure event entirely.
-        return;
-    }
     InputEventDataSource::Trace([&](InputEventDataSource::TraceContext ctx) {
         auto dataSource = ctx.GetDataSourceLocked();
         if (dataSource->shouldIgnoreTracedInputEvent(event.eventType)) {
             return;
         }
+        const TraceLevel traceLevel = dataSource->resolveTraceLevel(args);
+        if (traceLevel == TraceLevel::TRACE_LEVEL_NONE) {
+            return;
+        }
+        const bool isRedacted = traceLevel == TraceLevel::TRACE_LEVEL_REDACTED;
         auto tracePacket = ctx.NewTracePacket();
         auto* inputEvent = tracePacket->set_android_input_event();
-        auto* dispatchKey = inputEvent->set_dispatcher_key_event();
-        AndroidInputEventProtoConverter::toProtoKeyEvent(event, *dispatchKey);
+        auto* dispatchKey = isRedacted ? inputEvent->set_dispatcher_key_event_redacted()
+                                       : inputEvent->set_dispatcher_key_event();
+        AndroidInputEventProtoConverter::toProtoKeyEvent(event, *dispatchKey, isRedacted);
     });
 }
 
 void PerfettoBackend::traceWindowDispatch(const WindowDispatchArgs& dispatchArgs,
                                           const TracedEventArgs& args) {
-    if (args.isSecure) {
-        // For now, avoid tracing secure event entirely.
-        return;
-    }
     InputEventDataSource::Trace([&](InputEventDataSource::TraceContext ctx) {
         auto dataSource = ctx.GetDataSourceLocked();
         if (!dataSource->getFlags().test(TraceFlag::TRACE_DISPATCHER_WINDOW_DISPATCH)) {
             return;
         }
+        const TraceLevel traceLevel = dataSource->resolveTraceLevel(args);
+        if (traceLevel == TraceLevel::TRACE_LEVEL_NONE) {
+            return;
+        }
+        const bool isRedacted = traceLevel == TraceLevel::TRACE_LEVEL_REDACTED;
         auto tracePacket = ctx.NewTracePacket();
         auto* inputEvent = tracePacket->set_android_input_event();
-        auto* dispatchEvent = inputEvent->set_dispatcher_window_dispatch_event();
-        AndroidInputEventProtoConverter::toProtoWindowDispatchEvent(dispatchArgs, *dispatchEvent);
+        auto* dispatchEvent = isRedacted
+                ? inputEvent->set_dispatcher_window_dispatch_event_redacted()
+                : inputEvent->set_dispatcher_window_dispatch_event();
+        AndroidInputEventProtoConverter::toProtoWindowDispatchEvent(dispatchArgs, *dispatchEvent,
+                                                                    isRedacted);
     });
 }
 
diff --git a/services/inputflinger/dispatcher/trace/InputTracingPerfettoBackend.h b/services/inputflinger/dispatcher/trace/InputTracingPerfettoBackend.h
index 920ea60..c4f80c3 100644
--- a/services/inputflinger/dispatcher/trace/InputTracingPerfettoBackend.h
+++ b/services/inputflinger/dispatcher/trace/InputTracingPerfettoBackend.h
@@ -68,10 +68,13 @@
 
         bool shouldIgnoreTracedInputEvent(const EventType&) const;
         inline ftl::Flags<TraceFlag> getFlags() const { return mConfig.flags; }
+        TraceLevel resolveTraceLevel(const TracedEventArgs&) const;
 
     private:
         const int32_t mInstanceId;
         TraceConfig mConfig;
+
+        bool ruleMatches(const TraceRule&, const TracedEventArgs&) const;
     };
 
     static std::once_flag sDataSourceRegistrationFlag;