From 6b600182dd1923333c485577b5b7d4b1bdacd069 Mon Sep 17 00:00:00 2001
From: Michele Balistreri <opensource@bitgamma.com>
Date: Mon, 25 Sep 2017 12:26:15 +0300
Subject: [PATCH] begin application implementation

---
 README.md                                     | 10 +--
 .../java/im/status/wallet/WalletApplet.java   | 66 +++++++++++++++++--
 2 files changed, 67 insertions(+), 9 deletions(-)

diff --git a/README.md b/README.md
index 276b9ee..4c36efa 100644
--- a/README.md
+++ b/README.md
@@ -5,12 +5,12 @@ Currently just a skeleton for the hardware wallet.
 The .gpshell files are meant to be fed to GPShell. The statuswallet_install.gpshell file is actually dependent on the
 target hw. Currently it assumes that the default VISA AID and keys for the ISD are used, but the version number is 2.
 
-Other files will come and go until they are formalized as test scripts when we have a meaningful specification
-and implementation.
-
 The project is built using Gradle with the [Fidesmo Javacard Gradle plugin](https://github.com/fidesmo/gradle-javacard).
 You can set the JavaCard HOME not only through the enviroment but also creating a gradle.properties file with the property
 "com.fidesmo.gradle.javacard.home" set to the correct path
 
-This implementation will try to use only features available in JavaCard 2.2.2 for broader compatibility with existing
-hardware.
\ No newline at end of file
+## Implementation notes
+
+* This implementation will try to use only features available in JavaCard 2.2.2 for broader compatibility with existing
+hardware.
+* The class byte of the APDU is not checked since there are nor conflicting INS code.
\ No newline at end of file
diff --git a/src/main/java/im/status/wallet/WalletApplet.java b/src/main/java/im/status/wallet/WalletApplet.java
index c120fcc..257eb38 100644
--- a/src/main/java/im/status/wallet/WalletApplet.java
+++ b/src/main/java/im/status/wallet/WalletApplet.java
@@ -1,16 +1,32 @@
 package im.status.wallet;
 
-import javacard.framework.APDU;
-import javacard.framework.Applet;
-import javacard.framework.ISO7816;
-import javacard.framework.ISOException;
+import javacard.framework.*;
 
 public class WalletApplet extends Applet {
+  static final byte INS_VERIFY_PIN = (byte) 0x20;
+  static final byte INS_CHANGE_PIN = (byte) 0x21;
+  static final byte INS_UNBLOCK_PIN = (byte) 0x22;
+  static final byte INS_LOAD_KEY = (byte) 0xD0;
+  static final byte INS_SIGN = (byte) 0xC0;
+
+  static final byte PIN_LENGTH = 6;
+  static final byte PIN_MAX_RETRIES = 3;
+  static final short TMP_BUFFER_LENGTH = 32;
+
+  private OwnerPIN ownerPIN;
+  private byte[] tmp;
+
   public static void install(byte[] bArray, short bOffset, byte bLength) {
     new WalletApplet(bArray, bOffset, bLength);
   }
 
   public WalletApplet(byte[] bArray, short bOffset, byte bLength) {
+    tmp = JCSystem.makeTransientByteArray(TMP_BUFFER_LENGTH, JCSystem.CLEAR_ON_DESELECT);
+
+    Util.arrayFillNonAtomic(tmp, (short) 0, PIN_LENGTH, (byte) 0x30);
+    ownerPIN = new OwnerPIN(PIN_MAX_RETRIES, PIN_LENGTH);
+    ownerPIN.update(tmp, (short) 0, PIN_LENGTH);
+
     register(bArray, (short) (bOffset + 1), bArray[0]);
   }
 
@@ -20,6 +36,48 @@ public class WalletApplet extends Applet {
       return;
     }
 
+    byte[] apduBuffer = apdu.getBuffer();
+
+    switch(apduBuffer[ISO7816.OFFSET_INS]) {
+      case INS_VERIFY_PIN:
+        verifyPIN(apdu);
+        break;
+      case INS_CHANGE_PIN:
+        changePIN(apdu);
+        break;
+      case INS_UNBLOCK_PIN:
+        unblockPIN(apdu);
+        break;
+      case INS_LOAD_KEY:
+        loadKey(apdu);
+        break;
+      case INS_SIGN:
+        sign(apdu);
+        break;
+      default:
+        ISOException.throwIt(ISO7816.SW_INS_NOT_SUPPORTED);
+    }
+
     ISOException.throwIt(ISO7816.SW_INS_NOT_SUPPORTED);
   }
+
+  private void verifyPIN(APDU apdu) {
+    byte[] apduBuffer = apdu.getBuffer();
+
+    if (!ownerPIN.check(apduBuffer, ISO7816.OFFSET_CDATA, apduBuffer[ISO7816.OFFSET_LC])) {
+      ISOException.throwIt((short)((short) 0x63c0 | (short) ownerPIN.getTriesRemaining()));
+    }
+  }
+
+  private void changePIN(APDU apdu) {
+  }
+
+  private void unblockPIN(APDU apdu) {
+  }
+
+  private void loadKey(APDU apdu) {
+  }
+
+  private void sign(APDU apdu) {
+  }
 }