Prevent OOB POWER_VALUES array access if array doesn't have enough values

Author: CapnBry

src/include/target/Unified_ESP32_TX.h

@@ -46,6 +46,7 @@
 #define POWER_OUTPUT_VALUES hardware_i16_array(HARDWARE_power_values)
 #define POWER_OUTPUT_VALUES_COUNT hardware_int(HARDWARE_power_values_count)
 #define POWER_OUTPUT_VALUES2 hardware_i16_array(HARDWARE_power_values2)
+#define POWER_OUTPUT_VALUES2_COUNT POWER_OUTPUT_VALUES_COUNT
 #define POWER_OUTPUT_VALUES_DUAL hardware_i16_array(HARDWARE_power_values_dual)
 #define POWER_OUTPUT_VALUES_DUAL_COUNT hardware_int(HARDWARE_power_values_dual_count)
 

src/lib/POWERMGNT/POWERMGNT.cpp

@@ -78,8 +78,6 @@ PowerLevels_e PowerLevelContainer::CurrentPower = PWR_COUNT; // default "undefin
 PowerLevels_e POWERMGNT::FanEnableThreshold = PWR_250mW;
 int8_t POWERMGNT::CurrentSX1280Power = 0;
 
-static const int16_t *powerValues;
-static const int16_t *powerValuesDual;
 extern bool isUsingPrimaryFreqBand();
 
 static int8_t powerCaliValues[PWR_COUNT] = {0};
@@ -88,6 +86,11 @@ static int8_t powerCaliValues[PWR_COUNT] = {0};
 nvs_handle POWERMGNT::handle = 0;
 #endif
 
+// Get the POWER_VALUE_X to send to DAC/RF chip of the speficied index into the array
+// If the index is higher than the array has values, return the LOWEST power value
+// Maybe the user will realize they can't just set MaxPower to 2000mW and get more power
+#define SAFE_GET_POWER_VALUE(values, idx) (((idx) < (values##_COUNT)) ? (values)[idx] : (values)[0])
+
 PowerLevels_e POWERMGNT::incPower()
 {
     if (CurrentPower < getMaxPower())
@@ -109,7 +112,7 @@ PowerLevels_e POWERMGNT::decPower()
 void POWERMGNT::incSX1280Output()
 {
     // Power adjustment is capped to within +-3dB of the target power level to prevent power run-away
-    if (CurrentSX1280Power < 13 && CurrentSX1280Power < powerValues[CurrentPower] + 3)
+    if (CurrentSX1280Power < 13 && CurrentSX1280Power < SAFE_GET_POWER_VALUE(POWER_OUTPUT_VALUES, CurrentPower) + 3)
     {
         CurrentSX1280Power++;
         Radio.SetOutputPower(CurrentSX1280Power);
@@ -119,7 +122,7 @@ void POWERMGNT::incSX1280Output()
 void POWERMGNT::decSX1280Output()
 {
     // Power adjustment is capped to within +-3dB of the target power level to prevent power run-away
-    if (CurrentSX1280Power > -18 && CurrentSX1280Power > powerValues[CurrentPower] - 3)
+    if (CurrentSX1280Power > -18 && CurrentSX1280Power > SAFE_GET_POWER_VALUE(POWER_OUTPUT_VALUES, CurrentPower) - 3)
     {
         CurrentSX1280Power--;
         Radio.SetOutputPower(CurrentSX1280Power);
@@ -214,11 +217,6 @@ void POWERMGNT::init()
 {
     PowerLevelContainer::CurrentPower = PWR_COUNT;
 
-    powerValues = POWER_OUTPUT_VALUES;
-    if (POWER_OUTPUT_VALUES_DUAL != nullptr)
-    {
-        powerValuesDual = POWER_OUTPUT_VALUES_DUAL;
-    }
     LoadCalibration();
     setDefaultPower();
 }
@@ -244,43 +242,41 @@ void POWERMGNT::setDefaultPower()
 void POWERMGNT::setPower(PowerLevels_e Power)
 {
     Power = constrain(Power, getMinPower(), getMaxPower());
-    PowerLevels_e PowerDual = Power;
-
     if (Power == CurrentPower)
         return;
-    
     CurrentPower = Power;
 
     // When using SubHGz with CE, limit to a max of 25mW.
     #if defined(Regulatory_Domain_EU_CE_2400) && defined(RADIO_LR1121)
     if (Power > PWR_25mW && isUsingPrimaryFreqBand())
     {
-        Power = (MinPower > PWR_25mW) ? MinPower : PWR_25mW;
+        Power = (MinPower > PWR_25mW) ? getMinPower() : PWR_25mW;
     }
     #endif
 
+    const uint8_t powerIdx = Power - getMinPower();
     if (POWER_OUTPUT_DACWRITE)
     {
         if (POWER_OUTPUT_VALUES2 != nullptr)
         {
-            Radio.SetOutputPower(POWER_OUTPUT_VALUES2[Power - MinPower]);
+            Radio.SetOutputPower(SAFE_GET_POWER_VALUE(POWER_OUTPUT_VALUES2, powerIdx));
         }
         #if defined(PLATFORM_ESP32_S3) || defined(PLATFORM_ESP32_C3) || defined(PLATFORM_ESP8266)
         ERRLN("ESP32-S3/C3 and ESP8285 MCUs do not have a DAC");
         #else
-        dacWrite(GPIO_PIN_RFamp_APC2, powerValues[Power - MinPower]);
+        dacWrite(GPIO_PIN_RFamp_APC2, SAFE_GET_POWER_VALUE(POWER_OUTPUT_VALUES, powerIdx));
         #endif
     }
     else
     {
-        CurrentSX1280Power = powerValues[Power - MinPower] + powerCaliValues[Power];
+        CurrentSX1280Power = SAFE_GET_POWER_VALUE(POWER_OUTPUT_VALUES, powerIdx) + powerCaliValues[Power];
         Radio.SetOutputPower(CurrentSX1280Power);
     }
 
 #if defined(RADIO_LR1121)
     if (POWER_OUTPUT_VALUES_DUAL != nullptr)
     {
-        Radio.SetOutputPower(powerValuesDual[PowerDual - MinPower], false); // Set the high frequency power setting.
+        Radio.SetOutputPower(SAFE_GET_POWER_VALUE(POWER_OUTPUT_VALUES_DUAL, powerIdx), false); // Set the high frequency power setting.
     }
 #endif