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Commit 2358c136 authored by Harry Cutts's avatar Harry Cutts
Browse files

MotionEvent: add safe dumping method 

This method should allow us to log more details of an event in case of
validation failures, without potential for infinite recursion in getter
methods.

Bug: 379368465
Test: add a test to MotionEventTest that calls
      getHistoricalRawPointerCoords with an invalid pointer index, and
      check the logs when run with `atest --host`
Flag: EXEMPT logs only
Change-Id: I9c7084cedbc7e6f6834cd1b401da04d07d22ce35
parent ffbd83c6

include/input/Input.h

+9 −0
Original line number Diff line number Diff line
@@ -994,6 +994,15 @@ protected: 
    std::vector<PointerProperties> mPointerProperties;

    std::vector<nsecs_t> mSampleEventTimes;

    std::vector<PointerCoords> mSamplePointerCoords;



private:

    /**

     * Create a human-readable string representation of the event's data for debugging purposes.

     *

     * Unlike operator<<, this method does not assume that the event data is valid or consistent, or

     * call any accessor methods that might themselves call safeDump in the case of invalid data.

     */

    std::string safeDump() const;

};



std::ostream& operator<<(std::ostream& out, const MotionEvent& event);

libs/input/Input.cpp

+55 −8
Original line number Diff line number Diff line
@@ -685,11 +685,12 @@ void MotionEvent::setCursorPosition(float x, float y) { 


const PointerCoords* MotionEvent::getRawPointerCoords(size_t pointerIndex) const {

    if (CC_UNLIKELY(pointerIndex < 0 || pointerIndex >= getPointerCount())) {

        LOG(FATAL) << __func__ << ": Invalid pointer index " << pointerIndex << " for " << *this;

        LOG(FATAL) << __func__ << ": Invalid pointer index " << pointerIndex << " for "

                   << safeDump();

    }

    const size_t position = getHistorySize() * getPointerCount() + pointerIndex;

    if (CC_UNLIKELY(position < 0 || position >= mSamplePointerCoords.size())) {

        LOG(FATAL) << __func__ << ": Invalid array index " << position << " for " << *this;

        LOG(FATAL) << __func__ << ": Invalid array index " << position << " for " << safeDump();

    }

    return &mSamplePointerCoords[position];

}
@@ -705,17 +706,16 @@ float MotionEvent::getAxisValue(int32_t axis, size_t pointerIndex) const { 
const PointerCoords* MotionEvent::getHistoricalRawPointerCoords(

        size_t pointerIndex, size_t historicalIndex) const {

    if (CC_UNLIKELY(pointerIndex < 0 || pointerIndex >= getPointerCount())) {

        LOG(FATAL) << __func__ << ": Invalid pointer index " << pointerIndex

                   << "; should be between >0 and ≤" << getPointerCount();

        LOG(FATAL) << __func__ << ": Invalid pointer index " << pointerIndex << " for "

                   << safeDump();

    }

    if (CC_UNLIKELY(historicalIndex < 0 || historicalIndex > getHistorySize())) {

        LOG(FATAL) << __func__ << ": Invalid historical index " << historicalIndex

                   << "; should be >0 and ≤" << getHistorySize();

        LOG(FATAL) << __func__ << ": Invalid historical index " << historicalIndex << " for "

                   << safeDump();

    }

    const size_t position = historicalIndex * getPointerCount() + pointerIndex;

    if (CC_UNLIKELY(position < 0 || position >= mSamplePointerCoords.size())) {

        LOG(FATAL) << __func__ << ": Invalid array index " << position << "; should be >0 and ≤"

                   << mSamplePointerCoords.size();

        LOG(FATAL) << __func__ << ": Invalid array index " << position << " for " << safeDump();

    }

    return &mSamplePointerCoords[position];

}
@@ -1146,6 +1146,53 @@ bool MotionEvent::operator==(const android::MotionEvent& o) const { 
    // clang-format on

}



std::string MotionEvent::safeDump() const {

    std::stringstream out;

    // Field names have the m prefix here to make it easy to distinguish safeDump output from

    // operator<< output in logs.

    out << "MotionEvent { mAction=" << MotionEvent::actionToString(mAction);

    if (mActionButton != 0) {

        out << ", mActionButton=" << mActionButton;

    }

    if (mButtonState != 0) {

        out << ", mButtonState=" << mButtonState;

    }

    if (mClassification != MotionClassification::NONE) {

        out << ", mClassification=" << motionClassificationToString(mClassification);

    }

    if (mMetaState != 0) {

        out << ", mMetaState=" << mMetaState;

    }

    if (mFlags != 0) {

        out << ", mFlags=0x" << std::hex << mFlags << std::dec;

    }

    if (mEdgeFlags != 0) {

        out << ", mEdgeFlags=" << mEdgeFlags;

    }

    out << ", mDownTime=" << mDownTime;

    out << ", mDeviceId=" << mDeviceId;

    out << ", mSource=" << inputEventSourceToString(mSource);

    out << ", mDisplayId=" << mDisplayId;

    out << ", mEventId=0x" << std::hex << mId << std::dec;

    // Since we're not assuming the data is at all valid, we also limit the number of items that

    // might be printed from vectors, in case the vector's size field is corrupted.

    out << ", mPointerProperties=(" << mPointerProperties.size() << ")[";

    for (size_t i = 0; i < mPointerProperties.size() && i < MAX_POINTERS; i++) {

        out << (i > 0 ? ", " : "") << mPointerProperties.at(i);

    }

    out << "], mSampleEventTimes=(" << mSampleEventTimes.size() << ")[";

    for (size_t i = 0; i < mSampleEventTimes.size() && i < 256; i++) {

        out << (i > 0 ? ", " : "") << mSampleEventTimes.at(i);

    }

    out << "], mSamplePointerCoords=(" << mSamplePointerCoords.size() << ")[";

    for (size_t i = 0; i < mSamplePointerCoords.size() && i < MAX_POINTERS; i++) {

        const PointerCoords& coords = mSamplePointerCoords.at(i);

        out << (i > 0 ? ", " : "") << "(" << coords.getX() << ", " << coords.getY() << ")";

    }

    out << "] }";

    return out.str();

}



std::ostream& operator<<(std::ostream& out, const MotionEvent& event) {

    out << "MotionEvent { action=" << MotionEvent::actionToString(event.getAction());

    if (event.getActionButton() != 0) {