inputflinger: Add touchpad stack fuzzer

Heavily inspired by MultiTouchInputFuzzer, this one works similarly but
has additional code to fuzz touchpad setting values and device-specific
configuration. The evdev axis info is also fuzzed, since unspecified
resolution values have caused bugs in the Gestures library before.
(Other fuzzers only fuzz the status_t return value from
getAbsoluteAxisInfo, not the axis info struct itself.)

Bug: 264582512
Test: build with SANITIZE_TARGET=hwaddress, run for a while on a device
Change-Id: Ic22ac0f29d433fdf3c17331df620a39937ebd7eb
diff --git a/services/inputflinger/tests/fuzzers/TouchpadInputFuzzer.cpp b/services/inputflinger/tests/fuzzers/TouchpadInputFuzzer.cpp
new file mode 100644
index 0000000..ef9663a
--- /dev/null
+++ b/services/inputflinger/tests/fuzzers/TouchpadInputFuzzer.cpp
@@ -0,0 +1,176 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <limits>
+#include <string>
+#include <vector>
+
+#include <linux/input-event-codes.h>
+
+#include <FuzzContainer.h>
+#include <MapperHelpers.h>
+#include <TouchpadInputMapper.h>
+
+namespace android {
+
+namespace {
+
+void setAxisInfo(ThreadSafeFuzzedDataProvider& fdp, FuzzContainer& fuzzer, int axis) {
+    if (fdp.ConsumeBool()) {
+        fuzzer.setAbsoluteAxisInfo(axis,
+                                   RawAbsoluteAxisInfo{
+                                           .valid = fdp.ConsumeBool(),
+                                           .minValue = fdp.ConsumeIntegral<int32_t>(),
+                                           .maxValue = fdp.ConsumeIntegral<int32_t>(),
+                                           .flat = fdp.ConsumeIntegral<int32_t>(),
+                                           .fuzz = fdp.ConsumeIntegral<int32_t>(),
+                                           .resolution = fdp.ConsumeIntegral<int32_t>(),
+                                   });
+    }
+}
+
+void setAxisInfos(ThreadSafeFuzzedDataProvider& fdp, FuzzContainer& fuzzer) {
+    setAxisInfo(fdp, fuzzer, ABS_MT_SLOT);
+    setAxisInfo(fdp, fuzzer, ABS_MT_POSITION_X);
+    setAxisInfo(fdp, fuzzer, ABS_MT_POSITION_Y);
+    setAxisInfo(fdp, fuzzer, ABS_MT_PRESSURE);
+    setAxisInfo(fdp, fuzzer, ABS_MT_ORIENTATION);
+    setAxisInfo(fdp, fuzzer, ABS_MT_TOUCH_MAJOR);
+    setAxisInfo(fdp, fuzzer, ABS_MT_TOUCH_MINOR);
+    setAxisInfo(fdp, fuzzer, ABS_MT_WIDTH_MAJOR);
+    setAxisInfo(fdp, fuzzer, ABS_MT_WIDTH_MINOR);
+}
+
+const std::vector<std::string> boolPropertiesToFuzz = {
+        "gestureProp.Compute_Surface_Area_from_Pressure",
+        "gestureProp.Drumroll_Suppression_Enable",
+        "gestureProp.Fling_Buffer_Suppress_Zero_Length_Scrolls",
+        "gestureProp.Stationary_Wiggle_Filter_Enabled",
+};
+const std::vector<std::string> doublePropertiesToFuzz = {
+        "gestureProp.Fake_Timestamp_Delta",
+        "gestureProp.Finger_Moving_Energy",
+        "gestureProp.Finger_Moving_Hysteresis",
+        "gestureProp.IIR_a1",
+        "gestureProp.IIR_a2",
+        "gestureProp.IIR_b0",
+        "gestureProp.IIR_b1",
+        "gestureProp.IIR_b2",
+        "gestureProp.IIR_b3",
+        "gestureProp.Max_Allowed_Pressure_Change_Per_Sec",
+        "gestureProp.Max_Hysteresis_Pressure_Per_Sec",
+        "gestureProp.Max_Stationary_Move_Speed",
+        "gestureProp.Max_Stationary_Move_Speed_Hysteresis",
+        "gestureProp.Max_Stationary_Move_Suppress_Distance",
+        "gestureProp.Multiple_Palm_Width",
+        "gestureProp.Palm_Edge_Zone_Width",
+        "gestureProp.Palm_Eval_Timeout",
+        "gestureProp.Palm_Pressure",
+        "gestureProp.Palm_Width",
+        "gestureProp.Pressure_Calibration_Offset",
+        "gestureProp.Pressure_Calibration_Slope",
+        "gestureProp.Tap_Exclusion_Border_Width",
+        "gestureProp.Touchpad_Device_Output_Bias_on_X-Axis",
+        "gestureProp.Touchpad_Device_Output_Bias_on_Y-Axis",
+        "gestureProp.Two_Finger_Vertical_Close_Distance_Thresh",
+};
+
+void setDeviceSpecificConfig(ThreadSafeFuzzedDataProvider& fdp, FuzzContainer& fuzzer) {
+    // There are a great many gesture properties offered by the Gestures library, all of which could
+    // potentially be set in Input Device Configuration files. Maintaining a complete list is
+    // impractical, so instead we only fuzz properties which are used in at least one IDC file, or
+    // which are likely to be used in future (e.g. ones for controlling palm rejection).
+
+    if (fdp.ConsumeBool()) {
+        fuzzer.addProperty("gestureProp.Touchpad_Stack_Version",
+                           std::to_string(fdp.ConsumeIntegral<int>()));
+    }
+
+    for (auto& propertyName : boolPropertiesToFuzz) {
+        if (fdp.ConsumeBool()) {
+            fuzzer.addProperty(propertyName, fdp.ConsumeBool() ? "1" : "0");
+        }
+    }
+
+    for (auto& propertyName : doublePropertiesToFuzz) {
+        if (fdp.ConsumeBool()) {
+            fuzzer.addProperty(propertyName, std::to_string(fdp.ConsumeFloatingPoint<double>()));
+        }
+    }
+
+    if (fdp.ConsumeBool()) {
+        fuzzer.addProperty("gestureProp." + fdp.ConsumeRandomLengthString(),
+                           std::to_string(fdp.ConsumeIntegral<int>()));
+    }
+}
+
+void setTouchpadSettings(ThreadSafeFuzzedDataProvider& fdp, InputReaderConfiguration& config) {
+    config.touchpadPointerSpeed = fdp.ConsumeIntegralInRange(-7, 7);
+    config.touchpadNaturalScrollingEnabled = fdp.ConsumeBool();
+    config.touchpadTapToClickEnabled = fdp.ConsumeBool();
+    config.touchpadRightClickZoneEnabled = fdp.ConsumeBool();
+}
+
+} // namespace
+
+extern "C" int LLVMFuzzerTestOneInput(uint8_t* data, size_t size) {
+    std::shared_ptr<ThreadSafeFuzzedDataProvider> fdp =
+            std::make_shared<ThreadSafeFuzzedDataProvider>(data, size);
+    FuzzContainer fuzzer(fdp);
+    setAxisInfos(*fdp, fuzzer);
+    setDeviceSpecificConfig(*fdp, fuzzer);
+
+    auto policyConfig = fuzzer.getPolicyConfig();
+    // Some settings are fuzzed here, as well as in the main loop, to provide randomized data to the
+    // TouchpadInputMapper constructor.
+    setTouchpadSettings(*fdp, policyConfig);
+    policyConfig.pointerCaptureRequest.enable = fdp->ConsumeBool();
+    TouchpadInputMapper& mapper = fuzzer.getMapper<TouchpadInputMapper>(policyConfig);
+
+    // Loop through mapper operations until randomness is exhausted.
+    while (fdp->remaining_bytes() > 0) {
+        fdp->PickValueInArray<std::function<void()>>({
+                [&]() -> void {
+                    std::string dump;
+                    mapper.dump(dump);
+                },
+                [&]() -> void {
+                    InputDeviceInfo info;
+                    mapper.populateDeviceInfo(info);
+                },
+                [&]() -> void { mapper.getSources(); },
+                [&]() -> void {
+                    setTouchpadSettings(*fdp, policyConfig);
+                    policyConfig.pointerCaptureRequest.enable = fdp->ConsumeBool();
+                    std::list<NotifyArgs> unused =
+                            mapper.reconfigure(fdp->ConsumeIntegral<nsecs_t>(), policyConfig,
+                                               InputReaderConfiguration::Change(
+                                                       fdp->ConsumeIntegral<uint32_t>()));
+                },
+                [&]() -> void {
+                    std::list<NotifyArgs> unused = mapper.reset(fdp->ConsumeIntegral<nsecs_t>());
+                },
+                [&]() -> void {
+                    RawEvent event = getFuzzedRawEvent(*fdp);
+                    std::list<NotifyArgs> unused = mapper.process(&event);
+                },
+        })();
+    }
+
+    return 0;
+}
+
+} // namespace android