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hotfix for DMX-serial output (prevents random crashes caused by array bounds violations) #326

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Merged
softhack007 merged 12 commits into from
Jan 25, 2026
Merged

hotfix for DMX-serial output (prevents random crashes caused by array bounds violations) #326

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6ad6acf
align DMX output drivers with upstream
softhack007 Jan 25, 2026
900178c
only build DMX drivers when WLED_ENABLE_DMX
softhack007 Jan 25, 2026
fb73888
safeguards against array bounds violation
softhack007 Jan 25, 2026
279d48a
(minor) clarify compile-time messages for DMX drivers
softhack007 Jan 25, 2026
82f7130
indentation
softhack007 Jan 25, 2026
2628e91
fix max number of bytes to be sent
softhack007 Jan 25, 2026
f0753d6
robustness improvement
softhack007 Jan 25, 2026
8faa88e
chanSize expansion must account for start byte
softhack007 Jan 25, 2026
3150f3b
use correct DMXSerial object on -S2 and -C3
softhack007 Jan 25, 2026
e6e2348
protect start byte
softhack007 Jan 25, 2026
0718a6d
comment clarification
softhack007 Jan 25, 2026
57d63b7
ESPDMX robustness improvements
softhack007 Jan 25, 2026
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2 changes: 1 addition & 1 deletion wled00/dmx_input.cpp
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
#include "wled.h"

#ifdef WLED_ENABLE_DMX_INPUT
#pragma message "DMX physical input driver enabled"
#pragma message "DMX physical input driver (esp-dmx) enabled"

#ifdef ESP8266
#error DMX input is only supported on ESP32
Expand Down
4 changes: 2 additions & 2 deletions wled00/dmx_output.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@
*/

#ifdef WLED_ENABLE_DMX
#pragma message "DMX network output enabled"
#pragma message "DMX output enabled"

#define MAX_DMX_RATE 44 // max DMX update rate in Hz

Expand Down Expand Up @@ -99,7 +99,7 @@ void handleDMXOutput()
}

void initDMXOutput() {
#ifdef ESP8266
#if defined(ESP8266) || defined(CONFIG_IDF_TARGET_ESP32C3) || defined(CONFIG_IDF_TARGET_ESP32S2)
dmx.init(512); // initialize with bus length
#else
dmx.initWrite(512); // initialize with bus length
Expand Down
12 changes: 7 additions & 5 deletions wled00/src/dependencies/dmx/ESPDMX.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -11,12 +11,13 @@
// - - - - -

/* ----- LIBRARIES ----- */
#ifdef ESP8266
#if defined(WLED_ENABLE_DMX) && (defined(ESP8266) || defined(CONFIG_IDF_TARGET_ESP32C3) || defined(CONFIG_IDF_TARGET_ESP32S2))

#include <Arduino.h>

#include "ESPDMX.h"

#pragma message "using ESPDMX"


#define dmxMaxChannel 512
Expand All @@ -30,8 +31,8 @@
bool dmxStarted = false;
int sendPin = 2; //default on ESP8266

//DMX value array and size. Entry 0 will hold startbyte
uint8_t dmxDataStore[dmxMaxChannel] = {};
//DMX value array and size. Entry 0 will hold startbyte, so we need 512+1 elements
uint8_t dmxDataStore[dmxMaxChannel+1] = {};
int channelSize;


Expand Down Expand Up @@ -72,6 +73,7 @@ void DMXESPSerial::write(int Channel, uint8_t value) {

if (Channel < 1) Channel = 1;
if (Channel > channelSize) Channel = channelSize;
if (Channel > dmxMaxChannel) Channel = dmxMaxChannel; // WLEDMM protect against array bounds violation
if (value < 0) value = 0;
if (value > 255) value = 255;

Expand All @@ -98,12 +100,12 @@ void DMXESPSerial::update() {
//send data
Serial1.begin(DMXSPEED, DMXFORMAT);
digitalWrite(sendPin, LOW);
Serial1.write(dmxDataStore, channelSize);
Serial1.write(dmxDataStore, min(dmxMaxChannel+1, channelSize+1));
Serial1.flush();
delay(1);
Serial1.end();
}

// Function to update the DMX bus

#endif
#endif
22 changes: 14 additions & 8 deletions wled00/src/dependencies/dmx/SparkFunDMX.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -14,14 +14,16 @@ Distributed as-is; no warranty is given.
******************************************************************************/

/* ----- LIBRARIES ----- */
#if defined(ARDUINO_ARCH_ESP32)
#if defined(ARDUINO_ARCH_ESP32) && defined(WLED_ENABLE_DMX)

#include <Arduino.h>
#if !defined(CONFIG_IDF_TARGET_ESP32C3) && !defined(CONFIG_IDF_TARGET_ESP32S2)

#include "SparkFunDMX.h"
#include <HardwareSerial.h>

#pragma message "using SparkFunDMX"

#define dmxMaxChannel 512
#define defaultMax 32

Expand All @@ -34,8 +36,8 @@ static const int enablePin = -1; // disable the enable pin because it is not ne
static const int rxPin = -1; // disable the receiving pin because it is not needed - softhack007: Pin=-1 means "use default" not "disable"
static const int txPin = 2; // transmit DMX data over this pin (default is pin 2)

//DMX value array and size. Entry 0 will hold startbyte
static uint8_t dmxData[dmxMaxChannel] = { 0 };
//DMX value array and size. Entry 0 will hold startbyte, so we need 512+1 elements
static uint8_t dmxData[dmxMaxChannel+1] = { 0 };
static int chanSize = 0;
#if !defined(DMX_SEND_ONLY)
static int currentChannel = 0;
Expand Down Expand Up @@ -121,15 +123,17 @@ void SparkFunDMX::initWrite (int chanQuant) {
#if !defined(DMX_SEND_ONLY)
// Function to read DMX data
uint8_t SparkFunDMX::read(int Channel) {
if ((Channel > dmxMaxChannel) || (Channel < 1)) return 0; // WLEDMM prevent array out-of-bounds access
if (Channel > chanSize) Channel = chanSize;
return(dmxData[Channel - 1]); //subtract one to account for start byte
}
#endif

// Function to send DMX data
void SparkFunDMX::write(int Channel, uint8_t value) {
if (Channel < 0) Channel = 0;
if (Channel > chanSize) chanSize = Channel;
if (Channel < 1) Channel = 1;
if (Channel+1 > chanSize) chanSize = min(dmxMaxChannel +1, Channel+1); // WLEDMM "+1" as we need to account for start byte
if (Channel > dmxMaxChannel) Channel = dmxMaxChannel; // WLEDMM prevent array out-of-bounds access
dmxData[0] = 0;
dmxData[Channel] = value; //add one to account for start byte
}
Expand All @@ -149,7 +153,7 @@ void SparkFunDMX::update() {

//Send DMX data
DMXSerial.begin(DMXSPEED, DMXFORMAT, rxPin, txPin);//Begin the Serial port
DMXSerial.write(dmxData, chanSize);
DMXSerial.write(dmxData, min(dmxMaxChannel+1, chanSize)); // send max 513 bytes = start byte + 512 channels
DMXSerial.flush();
DMXSerial.end();//clear our DMX array, end the Hardware Serial port
}
Expand All @@ -160,9 +164,11 @@ void SparkFunDMX::update() {
{
while (DMXSerial.available())
{
dmxData[currentChannel++] = DMXSerial.read();
uint8_t newdata = DMXSerial.read();
if (currentChannel <= dmxMaxChannel)
dmxData[currentChannel++] = newdata;
}
if (currentChannel > chanSize) //Set the channel counter back to 0 if we reach the known end size of our packet
if ((currentChannel > chanSize) || (currentChannel > dmxMaxChannel)) //Set the channel counter back to 0 if we reach the known end size of our packet
{

portENTER_CRITICAL(&timerMux);
Expand Down
8 changes: 4 additions & 4 deletions wled00/wled.h
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Original file line number Diff line number Diff line change
Expand Up @@ -164,9 +164,9 @@
#endif

#ifdef WLED_ENABLE_DMX
#ifdef ESP8266
#if defined(ESP8266) || defined(CONFIG_IDF_TARGET_ESP32C3) || defined(CONFIG_IDF_TARGET_ESP32S2)
#include "src/dependencies/dmx/ESPDMX.h"
#else //ESP32
#else //ESP32 or ESP32-S3
#include "src/dependencies/dmx/SparkFunDMX.h"
#endif
#endif
Expand Down Expand Up @@ -468,9 +468,9 @@ WLED_GLOBAL bool arlsDisableGammaCorrection _INIT(true); // activate if
WLED_GLOBAL bool arlsForceMaxBri _INIT(false); // enable to force max brightness if source has very dark colors that would be black

#ifdef WLED_ENABLE_DMX
#ifdef ESP8266
#if defined(ESP8266) || defined(CONFIG_IDF_TARGET_ESP32C3) || defined(CONFIG_IDF_TARGET_ESP32S2)
WLED_GLOBAL DMXESPSerial dmx;
#else //ESP32
#else //ESP32 or ESP32-S3
WLED_GLOBAL SparkFunDMX dmx;
#endif
WLED_GLOBAL uint16_t e131ProxyUniverse _INIT(0); // output this E1.31 (sACN) / ArtNet universe via MAX485 (0 = disabled)
Expand Down