v1.4.1: fix for signed messages, able to bolus from x2 again

jwoglom · Dec 10, 2024 · db7ef33 · db7ef33
1 parent ed78bca
commit db7ef33
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Showing 6 changed files with 41 additions and 6 deletions.
diff --git a/androidLib/src/main/java/com/jwoglom/pumpx2/pump/PumpState.java b/androidLib/src/main/java/com/jwoglom/pumpx2/pump/PumpState.java
@@ -27,6 +27,7 @@ public class PumpState {
     static {
         PumpStateSupplier.pumpPairingCode = PumpState::getPairingCodeCached;
         PumpStateSupplier.jpakeDerivedSecretHex = PumpState::getJpakeDerivedSecretCached;
+        PumpStateSupplier.jpakeServerNonceHex = PumpState::getJpakeServerNonceCached;
         PumpStateSupplier.pumpTimeSinceReset = PumpState::getPumpTimeSinceReset;
         PumpStateSupplier.pumpApiVersion = PumpState::getPumpAPIVersion;
         PumpStateSupplier.actionsAffectingInsulinDeliveryEnabled = PumpState::actionsAffectingInsulinDeliveryEnabled;
@@ -69,6 +70,23 @@ public static String getJpakeDerivedSecretCached() {
         return savedJpakeDerivedSecret;
     }
 
+
+    private static final String JPAKE_SERVER_NONCE_PREF = "jpakeServerNonce";
+    public static String savedJpakeServerNonce = null;
+    public static String getJpakeServerNonce(Context context) {
+        savedJpakeServerNonce = prefs(context).getString(JPAKE_SERVER_NONCE_PREF, null);
+        return savedJpakeServerNonce;
+    }
+
+    public static void setJpakeServerNonce(Context context, String hexDerivedSecret) {
+        prefs(context).edit().putString(JPAKE_SERVER_NONCE_PREF, hexDerivedSecret).commit();
+        savedJpakeServerNonce = hexDerivedSecret;
+    }
+
+    public static String getJpakeServerNonceCached() {
+        return savedJpakeServerNonce;
+    }
+
     // This is used during packet generation for signed messages,
     // and is filled by calling TimeSinceResetRequest
     public static Long pumpTimeSinceReset = null;

diff --git a/androidLib/src/main/java/com/jwoglom/pumpx2/pump/bluetooth/TandemBluetoothHandler.java b/androidLib/src/main/java/com/jwoglom/pumpx2/pump/bluetooth/TandemBluetoothHandler.java
@@ -551,6 +551,8 @@ private synchronized void innerCharacteristicUpdate(@NotNull BluetoothPeripheral
                             PumpState.setSavedBluetoothMAC(context, peripheral.getAddress());
                             byte[] derivedSecret = JpakeAuthBuilder.getInstance().getDerivedSecret();
                             PumpState.setJpakeDerivedSecret(context, Hex.encodeHexString(derivedSecret));
+                            byte[] serverNonce = JpakeAuthBuilder.getInstance().getServerNonce();
+                            PumpState.setJpakeServerNonce(context, Hex.encodeHexString(serverNonce));
                             tandemPump.onPumpConnected(peripheral);
                         } else if (JpakeAuthBuilder.getInstance().invalid()) {
                             Timber.i("JpakeAuth DONE: Invalid");

diff --git a/androidLib/src/main/java/com/jwoglom/pumpx2/pump/bluetooth/TandemPump.java b/androidLib/src/main/java/com/jwoglom/pumpx2/pump/bluetooth/TandemPump.java
@@ -203,6 +203,7 @@ public void onPumpConnected(BluetoothPeripheral peripheral) {
 
         // hack: ensure cached in PumpState.
         Timber.i("JpakeDerivedSecret=%s", PumpState.getJpakeDerivedSecret(context));
+        Timber.i("JpakeServerNonce=%s", PumpState.getJpakeServerNonce(context));
 
         sendCommand(peripheral, new ApiVersionRequest());
         sendCommand(peripheral, new TimeSinceResetRequest());
@@ -249,6 +250,7 @@ public void pair(BluetoothPeripheral peripheral, @Nullable AbstractCentralChalle
             }
         } else if (PumpState.pairingCodeType == PairingCodeType.SHORT_6CHAR) {
             String jpakeSecretHex = PumpState.getJpakeDerivedSecret(context);
+            PumpState.setJpakeServerNonce(context, "");
             if (Strings.isNullOrEmpty(jpakeSecretHex)) {
                 Timber.i("TandemPump: pair(SHORT_6CHAR, pairingCode=" + pairingCode + ", BOOTSTRAP)");
                 JpakeAuthBuilder.clearInstance();

diff --git a/build.gradle b/build.gradle
@@ -11,7 +11,7 @@ plugins {
 }
 
 group = "com.jwoglom.pumpx2"
-version = "1.4.0"
+version = "1.4.1"
 
 java {
     //withJavadocJar()

diff --git a/messages/src/main/java/com/jwoglom/pumpx2/pump/messages/bluetooth/PumpStateSupplier.java b/messages/src/main/java/com/jwoglom/pumpx2/pump/messages/bluetooth/PumpStateSupplier.java
@@ -1,5 +1,7 @@
 package com.jwoglom.pumpx2.pump.messages.bluetooth;
 
+import com.google.common.base.Strings;
+import com.jwoglom.pumpx2.pump.messages.builders.crypto.Hkdf;
 import com.jwoglom.pumpx2.pump.messages.models.ApiVersion;
 import com.jwoglom.pumpx2.shared.Hex;
 import com.jwoglom.pumpx2.shared.L;
@@ -15,25 +17,32 @@ public class PumpStateSupplier {
     public static Supplier<byte[]> authenticationKey = PumpStateSupplier::determinePumpAuthKey;
     public static Supplier<String> pumpPairingCode = null;
     public static Supplier<String> jpakeDerivedSecretHex = null;
+    public static Supplier<String> jpakeServerNonceHex = null;
     public static Supplier<Long> pumpTimeSinceReset = null;
     public static Supplier<ApiVersion> pumpApiVersion = null;
     public static Supplier<Boolean> controlIQSupported = () -> false;
     public static Supplier<Boolean> actionsAffectingInsulinDeliveryEnabled = () -> false;
 
 
     private static byte[] determinePumpAuthKey() {
-        String jpake = jpakeDerivedSecretHex == null ? null : jpakeDerivedSecretHex.get();
+        String derivedSecret = jpakeDerivedSecretHex == null ? null : jpakeDerivedSecretHex.get();
+        String serverNonce = jpakeServerNonceHex == null ? null : jpakeServerNonceHex.get();
         String code = pumpPairingCode == null ? null : pumpPairingCode.get();
 
-        if (jpake == null && code == null) {
+        if (derivedSecret == null && code == null) {
             throw new IllegalStateException("no pump authenticationKey");
         }
 
         // stored jpake raw derived secret is decoded from hex for use in hmac
-        if (jpake != null && !jpake.isEmpty()) {
+        if (!Strings.isNullOrEmpty(derivedSecret) && !Strings.isNullOrEmpty(serverNonce)) {
             try {
-                L.i(TAG, "PUMP_AUTHENTICATION_KEY=" + jpake);
-                return Hex.decodeHex(jpake);
+                L.i(TAG, "PUMP_JPAKE_DERIVED_SECRET=" + derivedSecret + " PUMP_JPAKE_SERVER_NONCE=" + serverNonce);
+                byte[] jpakeSecret = Hex.decodeHex(derivedSecret);
+                byte[] jpakeNonce = Hex.decodeHex(serverNonce);
+                byte[] authKey = Hkdf.build(jpakeNonce, jpakeSecret);
+                L.i(TAG, "PUMP_AUTHENTICATION_KEY=" + Hex.encodeHexString(authKey) + " PUMP_JPAKE_DERIVED_SECRET=" + derivedSecret + " PUMP_JPAKE_SERVER_NONCE=" + serverNonce);
+
+                return authKey;
             } catch (DecoderException e) {
                 L.e(TAG, e);
             }

diff --git a/messages/src/main/java/com/jwoglom/pumpx2/pump/messages/builders/JpakeAuthBuilder.java b/messages/src/main/java/com/jwoglom/pumpx2/pump/messages/builders/JpakeAuthBuilder.java
@@ -278,4 +278,8 @@ public boolean invalid() {
     public byte[] getDerivedSecret() {
         return this.derivedSecret;
     }
+
+    public byte[] getServerNonce() {
+        return this.serverNonce3;
+    }
 }