[modbus] Off-by-one fixes for data thing read index validation (openh…

…ab#8301) Fixes openhab#8300 Signed-off-by: Sami Salonen <[email protected]>
markus7017 · Sep 18, 2020 · 2e73959 · 2e73959
1 parent 7df74ec
commit 2e73959
Show file tree

Hide file tree

Showing 2 changed files with 17 additions and 1 deletion.
diff --git a/...bus/src/main/java/org/openhab/binding/modbus/internal/handler/ModbusDataThingHandler.java b/...bus/src/main/java/org/openhab/binding/modbus/internal/handler/ModbusDataThingHandler.java
@@ -631,7 +631,7 @@ private void validateReadIndex() throws ModbusConfigurationException {
 
         // Determine bit positions polled, both start and end inclusive
         int pollStartBitIndex = readRequest.getReference() * dataElementBits;
-        int pollEndBitIndex = pollStartBitIndex + readRequest.getDataLength() * dataElementBits;
+        int pollEndBitIndex = pollStartBitIndex + readRequest.getDataLength() * dataElementBits - 1;
 
         // Determine bit positions read, both start and end inclusive
         int readStartBitIndex = readIndex.get() * dataElementBits + readSubIndex.orElse(0) * valueTypeBitCount;

diff --git a/...ng.modbus.tests/src/main/java/org/openhab/binding/modbus/tests/ModbusDataHandlerTest.java b/...ng.modbus.tests/src/main/java/org/openhab/binding/modbus/tests/ModbusDataHandlerTest.java
@@ -293,8 +293,16 @@ public void testInitCoilsOutOfIndex() {
                 ThingStatus.OFFLINE);
     }
 
+    @Test
+    public void testInitCoilsOutOfIndex2() {
+        // Reading coils 4, 5, 6. Coil 7 is out of bounds
+        testOutOfBoundsGeneric(4, 3, "7", ModbusReadFunctionCode.READ_COILS, ModbusConstants.ValueType.BIT,
+                ThingStatus.OFFLINE);
+    }
+
     @Test
     public void testInitCoilsOK() {
+        // Reading coils 4, 5, 6. Coil 6 is OK
         testOutOfBoundsGeneric(4, 3, "6", ModbusReadFunctionCode.READ_COILS, ModbusConstants.ValueType.BIT,
                 ThingStatus.ONLINE);
     }
@@ -349,12 +357,20 @@ public void testInitRegistersWithInt8OK2() {
 
     @Test
     public void testInitRegistersWithInt16OK() {
+        // Poller reading registers 4, 5, 6. Register 6 is OK
         testOutOfBoundsGeneric(4, 3, "6", ModbusReadFunctionCode.READ_MULTIPLE_REGISTERS,
                 ModbusConstants.ValueType.INT16, ThingStatus.ONLINE);
     }
 
     @Test
     public void testInitRegistersWithInt16OutOfBounds() {
+        // Poller reading registers 4, 5, 6. Register 7 is out-of-bounds
+        testOutOfBoundsGeneric(4, 3, "7", ModbusReadFunctionCode.READ_MULTIPLE_REGISTERS,
+                ModbusConstants.ValueType.INT16, ThingStatus.OFFLINE);
+    }
+
+    @Test
+    public void testInitRegistersWithInt16OutOfBounds2() {
         testOutOfBoundsGeneric(4, 3, "8", ModbusReadFunctionCode.READ_MULTIPLE_REGISTERS,
                 ModbusConstants.ValueType.INT16, ThingStatus.OFFLINE);
     }