From 09d2b5be1f4218d3dd90df88bb6ca5e3f331b8b8 Mon Sep 17 00:00:00 2001
From: catbref <misc-github@talk2dom.com>
Date: Tue, 9 Jun 2020 10:57:39 +0100
Subject: [PATCH] Fix off-by-one error with data address bounds & unit test to
 cover

---
 Java/src/main/java/org/ciyam/at/Utils.java     |  2 +-
 Java/src/test/java/org/ciyam/at/MiscTests.java | 14 ++++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/Java/src/main/java/org/ciyam/at/Utils.java b/Java/src/main/java/org/ciyam/at/Utils.java
index d03dcb7..34e9ab6 100644
--- a/Java/src/main/java/org/ciyam/at/Utils.java
+++ b/Java/src/main/java/org/ciyam/at/Utils.java
@@ -71,7 +71,7 @@ interface Utils {
 		try {
 			final int address = codeByteBuffer.getInt() * MachineState.VALUE_SIZE;
 
-			if (address < 0 || address + MachineState.VALUE_SIZE >= dataByteBuffer.limit())
+			if (address < 0 || address + MachineState.VALUE_SIZE > dataByteBuffer.limit())
 				throw new InvalidAddressException("Data address out of bounds");
 
 			return address;
diff --git a/Java/src/test/java/org/ciyam/at/MiscTests.java b/Java/src/test/java/org/ciyam/at/MiscTests.java
index 8a3175d..4bc9178 100644
--- a/Java/src/test/java/org/ciyam/at/MiscTests.java
+++ b/Java/src/test/java/org/ciyam/at/MiscTests.java
@@ -68,4 +68,18 @@ public class MiscTests extends ExecutableTest {
 		assertEquals((Long) (minActivationAmount - 1L), state.getFrozenBalance());
 	}
 
+	@Test
+	public void testDataAddressBounds() throws ExecutionException {
+		// Last possible valid address in data segment
+		int lastDataAddress = (dataByteBuffer.limit() / MachineState.VALUE_SIZE) - 1;
+
+		codeByteBuffer.put(OpCode.SET_VAL.value).putInt(lastDataAddress).putLong(8888L);
+		codeByteBuffer.put(OpCode.FIN_IMD.value);
+
+		execute(true);
+
+		assertTrue(state.isFinished());
+		assertFalse(state.hadFatalError());
+	}
+
 }