diff options
author | Arthur Ishiguro <arthuri@google.com> | 2020-09-22 13:05:15 -0700 |
---|---|---|
committer | Arthur Ishiguro <arthuri@google.com> | 2020-10-03 08:52:06 -0700 |
commit | 3b27b3b3bb36274171a9abb31f3e3f6b53036cf0 (patch) | |
tree | 83c39cc001d7152c100cb92bed70151a2d5f252f | |
parent | 01f9863464fb07aea1f7f2180ec4eb76ab7e25ed (diff) | |
download | native-3b27b3b3bb36274171a9abb31f3e3f6b53036cf0.tar.gz |
Prevent mEventCache UAF in SensorEventConnection
Since there is no check to see if SensorEventConnection has been
destroyed, the mEventCache pointer can still be used even after it
was freed.
Bug: 168211968
Test: Run test code that attempts to enable a sensor after destroying
the SensorEventConnection, and verify no system_server crash occurs.
Change-Id: Ia9275b7cc574df371cdb2e1b80c6699df193b580
Merged-In: Ia9275b7cc574df371cdb2e1b80c6699df193b580
-rw-r--r-- | services/sensorservice/SensorEventConnection.cpp | 28 | ||||
-rw-r--r-- | services/sensorservice/SensorEventConnection.h | 6 |
2 files changed, 22 insertions, 12 deletions
diff --git a/services/sensorservice/SensorEventConnection.cpp b/services/sensorservice/SensorEventConnection.cpp index 956844f426..a9e8321dcf 100644 --- a/services/sensorservice/SensorEventConnection.cpp +++ b/services/sensorservice/SensorEventConnection.cpp @@ -14,6 +14,7 @@ * limitations under the License. */ +#include <log/log.h> #include <sys/socket.h> #include <utils/threads.h> @@ -44,20 +45,13 @@ SensorService::SensorEventConnection::SensorEventConnection( SensorService::SensorEventConnection::~SensorEventConnection() { ALOGD_IF(DEBUG_CONNECTIONS, "~SensorEventConnection(%p)", this); destroy(); -} - -void SensorService::SensorEventConnection::destroy() { - Mutex::Autolock _l(mDestroyLock); - - // destroy once only - if (mDestroyed) { - return; - } - mService->cleanupConnection(this); if (mEventCache != NULL) { delete mEventCache; } +} + +void SensorService::SensorEventConnection::destroy() { mDestroyed = true; } @@ -555,6 +549,11 @@ status_t SensorService::SensorEventConnection::enableDisable( int handle, bool enabled, nsecs_t samplingPeriodNs, nsecs_t maxBatchReportLatencyNs, int reservedFlags) { + if (mDestroyed) { + android_errorWriteLog(0x534e4554, "168211968"); + return DEAD_OBJECT; + } + status_t err; if (enabled) { err = mService->enable(this, handle, samplingPeriodNs, maxBatchReportLatencyNs, @@ -569,10 +568,19 @@ status_t SensorService::SensorEventConnection::enableDisable( status_t SensorService::SensorEventConnection::setEventRate( int handle, nsecs_t samplingPeriodNs) { + if (mDestroyed) { + android_errorWriteLog(0x534e4554, "168211968"); + return DEAD_OBJECT; + } + return mService->setEventRate(this, handle, samplingPeriodNs, mOpPackageName); } status_t SensorService::SensorEventConnection::flush() { + if (mDestroyed) { + return DEAD_OBJECT; + } + return mService->flushSensor(this, mOpPackageName); } diff --git a/services/sensorservice/SensorEventConnection.h b/services/sensorservice/SensorEventConnection.h index 032721ea39..84b4d86879 100644 --- a/services/sensorservice/SensorEventConnection.h +++ b/services/sensorservice/SensorEventConnection.h @@ -17,6 +17,7 @@ #ifndef ANDROID_SENSOR_EVENT_CONNECTION_H #define ANDROID_SENSOR_EVENT_CONNECTION_H +#include <atomic> #include <stdint.h> #include <sys/types.h> @@ -168,8 +169,9 @@ private: int mTotalAcksNeeded, mTotalAcksReceived; #endif - mutable Mutex mDestroyLock; - bool mDestroyed; + // Used to track if this object was inappropriately used after destroy(). + std::atomic_bool mDestroyed; + bool mHasSensorAccess; }; |