core: don't process debug info if offset is incorrect (#259)

jadx-core/src/main/java/jadx/core/dex/nodes/DexNode.java

@@ -190,6 +190,10 @@ public class DexNode implements IDexNode {
 		return dexBuf.open(offset);
 	}
 
+	public boolean checkOffset(int dataOffset) {
+		return dataOffset >= 0 && dataOffset < dexBuf.getLength();
+	}
+
 	@Override
 	public RootNode root() {
 		return root;
@@ -208,4 +212,5 @@ public class DexNode implements IDexNode {
 	public String toString() {
 		return "DEX";
 	}
+
 }

jadx-core/src/main/java/jadx/core/dex/visitors/DebugInfoVisitor.java

@@ -22,7 +22,7 @@ public class DebugInfoVisitor extends AbstractVisitor {
 	public void visit(MethodNode mth) throws JadxException {
 		try {
 			int debugOffset = mth.getDebugInfoOffset();
-			if (debugOffset > 0) {
+			if (debugOffset > 0 && mth.dex().checkOffset(debugOffset)) {
 				processDebugInfo(mth, debugOffset);
 			}
 		} catch (Exception e) {