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Port, port handle, & port name validation #620

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3c7595b
Validate port pointers and stuff
ButterscotchV Dec 11, 2025
ac8d696
Validate port names
ButterscotchV Dec 11, 2025
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108 changes: 91 additions & 17 deletions src/main/c/Windows/SerialPort_Windows.c
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Original file line number Diff line number Diff line change
Expand Up @@ -801,7 +801,18 @@ JNIEXPORT void JNICALL Java_com_fazecast_jSerialComm_SerialPort_retrievePortDeta
jstring portNameJString = (jstring)(*env)->GetObjectField(env, obj, comPortField);
if (checkJniError(env, __LINE__ - 1)) return;
const wchar_t *portName = (wchar_t*)(*env)->GetStringChars(env, portNameJString, NULL);
if (checkJniError(env, __LINE__ - 1)) return;
if (checkJniError(env, __LINE__ - 1))
{
if (portName)
(*env)->ReleaseStringChars(env, portNameJString, (const jchar*)portName);
return;
}
if (!portName)
{
lastErrorLineNumber = __LINE__ - 9;
lastErrorNumber = ERROR_INVALID_PARAMETER;
return;
}

// Ensure that the serial port exists
char continueRetrieval = 1;
Expand Down Expand Up @@ -874,7 +885,18 @@ JNIEXPORT jlong JNICALL Java_com_fazecast_jSerialComm_SerialPort_openPortNative(
unsigned char isRtsEnabled = (*env)->GetBooleanField(env, obj, isRtsEnabledField);
if (checkJniError(env, __LINE__ - 1)) return 0;
const wchar_t *portName = (wchar_t*)(*env)->GetStringChars(env, portNameJString, NULL);
if (checkJniError(env, __LINE__ - 1)) return 0;
if (checkJniError(env, __LINE__ - 1))
{
if (portName)
(*env)->ReleaseStringChars(env, portNameJString, (const jchar*)portName);
return 0;
}
if (!portName)
{
lastErrorLineNumber = __LINE__ - 9;
lastErrorNumber = ERROR_INVALID_PARAMETER;
return 0;
}

// Ensure that the serial port still exists and is not already open
EnterCriticalSection(&criticalSection);
Expand Down Expand Up @@ -1132,10 +1154,12 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_flushRxTxBuf

JNIEXPORT jint JNICALL Java_com_fazecast_jSerialComm_SerialPort_waitForEvent(JNIEnv *env, jobject obj, jlong serialPortPointer)
{
// Create an asynchronous event structure
// Validate port and create an asynchronous event structure
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
return com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_PORT_DISCONNECTED;
OVERLAPPED overlappedStruct;
memset(&overlappedStruct, 0, sizeof(OVERLAPPED));
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
overlappedStruct.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
jint event = com_fazecast_jSerialComm_SerialPort_LISTENING_EVENT_TIMED_OUT;
if (!overlappedStruct.hEvent)
Expand Down Expand Up @@ -1211,10 +1235,14 @@ JNIEXPORT jint JNICALL Java_com_fazecast_jSerialComm_SerialPort_waitForEvent(JNI

JNIEXPORT jlong JNICALL Java_com_fazecast_jSerialComm_SerialPort_closePortNative(JNIEnv *env, jobject obj, jlong serialPortPointer)
{
// Validate port pointer and handle
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
return 0;

// Force the port to enter non-blocking mode to ensure that any current reads return
COMMTIMEOUTS timeouts;
memset(&timeouts, 0, sizeof(COMMTIMEOUTS));
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
timeouts.WriteTotalTimeoutMultiplier = 0;
timeouts.ReadIntervalTimeout = MAXDWORD;
timeouts.ReadTotalTimeoutMultiplier = 0;
Expand Down Expand Up @@ -1243,36 +1271,50 @@ JNIEXPORT jint JNICALL Java_com_fazecast_jSerialComm_SerialPort_bytesAvailable(J
// Retrieve bytes available to read
COMSTAT commInfo;
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
{
lastErrorLineNumber = __LINE__ - 2;
lastErrorNumber = ERROR_INVALID_HANDLE;
return -1;
}
if (ClearCommError(port->handle, NULL, &commInfo))
return commInfo.cbInQue;
else
{
port->errorLineNumber = __LINE__ - 4;
port->errorNumber = GetLastError();
return -1;
}
return -1;
}

JNIEXPORT jint JNICALL Java_com_fazecast_jSerialComm_SerialPort_bytesAwaitingWrite(JNIEnv *env, jobject obj, jlong serialPortPointer)
{
// Retrieve bytes awaiting write
COMSTAT commInfo;
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
{
lastErrorLineNumber = __LINE__ - 2;
lastErrorNumber = ERROR_INVALID_HANDLE;
return -1;
}
if (ClearCommError(port->handle, NULL, &commInfo))
return commInfo.cbOutQue;
else
{
port->errorLineNumber = __LINE__ - 4;
port->errorNumber = GetLastError();
return -1;
}
return -1;
}

JNIEXPORT jint JNICALL Java_com_fazecast_jSerialComm_SerialPort_readBytes(JNIEnv *env, jobject obj, jlong serialPortPointer, jbyteArray buffer, jint bytesToRead, jint offset, jint timeoutMode, jint readTimeout)
{
// Ensure that a positive number of bytes was passed in to read
jsize bufferLength = (*env)->GetArrayLength(env, buffer);
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
return -1;
if ((bytesToRead < 0) || (offset < 0) || (bufferLength < offset))
return -1;

Expand All @@ -1291,13 +1333,12 @@ JNIEXPORT jint JNICALL Java_com_fazecast_jSerialComm_SerialPort_readBytes(JNIEnv
{
port->errorNumber = GetLastError();
port->errorLineNumber = __LINE__ - 4;
CloseHandle(overlappedStruct.hEvent);
(*env)->ReleaseByteArrayElements(env, buffer, readBuffer, JNI_ABORT);
return -1;
}

// Read from the serial port
BOOL result;
BOOL result = FALSE;
DWORD numBytesRead = 0;
if (((result = ReadFile(port->handle, readBuffer + offset, bytesToRead, NULL, &overlappedStruct)) == FALSE) && (GetLastError() != ERROR_IO_PENDING))
{
Expand All @@ -1321,6 +1362,8 @@ JNIEXPORT jint JNICALL Java_com_fazecast_jSerialComm_SerialPort_writeBytes(JNIEn
{
// Ensure that a positive number of bytes was passed in to write
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
return -1;
if ((bytesToWrite < 0) || (offset < 0))
return -1;

Expand All @@ -1340,13 +1383,12 @@ JNIEXPORT jint JNICALL Java_com_fazecast_jSerialComm_SerialPort_writeBytes(JNIEn
{
port->errorNumber = GetLastError();
port->errorLineNumber = __LINE__ - 4;
CloseHandle(overlappedStruct.hEvent);
(*env)->ReleaseByteArrayElements(env, buffer, writeBuffer, JNI_ABORT);
return -1;
}

// Write to the serial port
BOOL result;
BOOL result = FALSE;
DWORD numBytesWritten = 0;
if (((result = WriteFile(port->handle, writeBuffer + offset, bytesToWrite, NULL, &overlappedStruct)) == FALSE) && (GetLastError() != ERROR_IO_PENDING))
{
Expand All @@ -1368,12 +1410,17 @@ JNIEXPORT jint JNICALL Java_com_fazecast_jSerialComm_SerialPort_writeBytes(JNIEn

JNIEXPORT void JNICALL Java_com_fazecast_jSerialComm_SerialPort_setEventListeningStatus(JNIEnv *env, jobject obj, jlong serialPortPointer, jboolean eventListenerRunning)
{
((serialPort*)(intptr_t)serialPortPointer)->eventListenerRunning = eventListenerRunning;
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port)
return;
port->eventListenerRunning = eventListenerRunning;
}

JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_setBreak(JNIEnv *env, jobject obj, jlong serialPortPointer)
{
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
return JNI_FALSE;
if (!SetCommBreak(port->handle))
{
port->errorLineNumber = __LINE__ - 2;
Expand All @@ -1386,6 +1433,8 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_setBreak(JNI
JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_clearBreak(JNIEnv *env, jobject obj, jlong serialPortPointer)
{
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
return JNI_FALSE;
if (!ClearCommBreak(port->handle))
{
port->errorLineNumber = __LINE__ - 2;
Expand All @@ -1398,6 +1447,8 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_clearBreak(J
JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_setRTS(JNIEnv *env, jobject obj, jlong serialPortPointer)
{
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
return JNI_FALSE;
if (!EscapeCommFunction(port->handle, SETRTS))
{
port->errorLineNumber = __LINE__ - 2;
Expand All @@ -1410,6 +1461,8 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_setRTS(JNIEn
JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_clearRTS(JNIEnv *env, jobject obj, jlong serialPortPointer)
{
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
return JNI_FALSE;
if (!EscapeCommFunction(port->handle, CLRRTS))
{
port->errorLineNumber = __LINE__ - 2;
Expand All @@ -1422,6 +1475,8 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_clearRTS(JNI
JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_setDTR(JNIEnv *env, jobject obj, jlong serialPortPointer)
{
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
return JNI_FALSE;
if (!EscapeCommFunction(port->handle, SETDTR))
{
port->errorLineNumber = __LINE__ - 2;
Expand All @@ -1434,6 +1489,8 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_setDTR(JNIEn
JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_clearDTR(JNIEnv *env, jobject obj, jlong serialPortPointer)
{
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
return JNI_FALSE;
if (!EscapeCommFunction(port->handle, CLRDTR))
{
port->errorLineNumber = __LINE__ - 2;
Expand All @@ -1449,6 +1506,8 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_setDTRandRTS
// So we must call EscapeCommFunction separately for each line.
// This still typically results in a single USB control transfer on Windows CDC drivers.
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
return JNI_FALSE;
if (!EscapeCommFunction(port->handle, dtr ? SETDTR : CLRDTR))
{
port->errorLineNumber = __LINE__ - 2;
Expand All @@ -1467,19 +1526,28 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_setDTRandRTS
JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_getCTS(JNIEnv *env, jobject obj, jlong serialPortPointer)
{
DWORD modemStatus = 0;
return GetCommModemStatus(((serialPort*)(intptr_t)serialPortPointer)->handle, &modemStatus) && (modemStatus & MS_CTS_ON);
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
return JNI_FALSE;
return GetCommModemStatus(port->handle, &modemStatus) && (modemStatus & MS_CTS_ON);
}

JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_getDSR(JNIEnv *env, jobject obj, jlong serialPortPointer)
{
DWORD modemStatus = 0;
return GetCommModemStatus(((serialPort*)(intptr_t)serialPortPointer)->handle, &modemStatus) && (modemStatus & MS_DSR_ON);
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
return JNI_FALSE;
return GetCommModemStatus(port->handle, &modemStatus) && (modemStatus & MS_DSR_ON);
}

JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_getDCD(JNIEnv *env, jobject obj, jlong serialPortPointer)
{
DWORD modemStatus = 0;
return GetCommModemStatus(((serialPort*)(intptr_t)serialPortPointer)->handle, &modemStatus) && (modemStatus & MS_RLSD_ON);
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
return JNI_FALSE;
return GetCommModemStatus(port->handle, &modemStatus) && (modemStatus & MS_RLSD_ON);
}

JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_getDTR(JNIEnv *env, jobject obj, jlong serialPortPointer)
Expand All @@ -1495,12 +1563,18 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_getRTS(JNIEn
JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_getRI(JNIEnv *env, jobject obj, jlong serialPortPointer)
{
DWORD modemStatus = 0;
return GetCommModemStatus(((serialPort*)(intptr_t)serialPortPointer)->handle, &modemStatus) && (modemStatus & MS_RING_ON);
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
return JNI_FALSE;
return GetCommModemStatus(port->handle, &modemStatus) && (modemStatus & MS_RING_ON);
}

JNIEXPORT void JNICALL Java_com_fazecast_jSerialComm_SerialPort_quickConfig(JNIEnv *env, jobject obj, jlong serialPortPointer, jint newDataBits, jint newStopBits, jint newParity)
{
void *portHandle = ((serialPort*)(intptr_t)serialPortPointer)->handle;
serialPort *port = (serialPort*)(intptr_t)serialPortPointer;
if (!port || (port->handle == INVALID_HANDLE_VALUE))
return;
void *portHandle = port->handle;
DCB dcbSerialParams;
memset(&dcbSerialParams, 0, sizeof(DCB));
dcbSerialParams.DCBlength = sizeof(DCB);
Expand Down