Fix incorrect response format of some devices. (#26)

fidesmo · Mar 29, 2019 · 304c9fe · 304c9fe
1 parent d60b574
commit 304c9fe
Showing 1 changed file with 15 additions and 1 deletion.
diff --git a/src/main/java/com/fidesmo/fdsm/FidesmoCard.java b/src/main/java/com/fidesmo/fdsm/FidesmoCard.java
@@ -250,7 +250,7 @@ public boolean detect() throws CardException {
         if (response.getSW() != 0x9000)
             return false;
         BerTlvParser parser = new BerTlvParser();
-        BerTlvs tlvs = parser.parse(response.getData());
+        BerTlvs tlvs = parser.parse(fixup(response.getData()));
         BerTlv batchIdTag = tlvs.find(new BerTag(0x42));
         if (batchIdTag != null) {
             batchId = batchIdTag.getBytesValue();
@@ -282,6 +282,20 @@ public boolean detect() throws CardException {
         return true;
     }
 
+    // Remove the trailing 0x00 if the format is not TLV
+    private byte[] fixup(byte[] v) {
+        if (v.length > 0 && v[v.length - 1] == 0x00) {
+            try {
+                BerTlvParser parser = new BerTlvParser();
+                parser.parse(v);
+                return v;
+            } catch (ArrayIndexOutOfBoundsException e) {
+                return Arrays.copyOf(v, v.length - 1);
+            }
+        }
+        return v;
+    }
+
     public List<byte[]> listApps() throws CardException {
         // Fidesmo RID
         final byte[] prefix = HexUtils.hex2bin("A00000061701");