WIP: add Milenage

AUTN is not correct yet

omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/OmnipodDashBleManagerImpl.kt

@@ -133,9 +133,9 @@ class OmnipodDashBleManagerImpl @Inject constructor(
 
             aapsLogger.info(LTag.PUMPCOMM, "Got LTK: ${ltk.ltk.toHex()}")
 
-            emitter.onNext(PodEvent.EstablishingSession)
+           // emitter.onNext(PodEvent.EstablishingSession)
 
-            val EapAkaExchanger = EapAkaExchanger(msgIO, ltk)
+            val EapAkaExchanger = EapAkaExchanger(aapsLogger, msgIO, ltk)
             val sessionKeys = EapAkaExchanger.negotiateSessionKeys()
             aapsLogger.info(LTag.PUMPCOMM, "Got session Key: $sessionKeys")
 

omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/pair/LTKExchanger.kt

@@ -182,7 +182,7 @@ internal class LTKExchanger(private val aapsLogger: AAPSLogger, private val msgI
             pdmPublic.copyOfRange(pdmPublic.size - 4, pdmPublic.size) +
             podNonce.copyOfRange(podNonce.size - 4, podNonce.size) +
             pdmNonce.copyOfRange(pdmNonce.size - 4, pdmNonce.size)
-        aapsLogger.debug(LTag.PUMPBTCOMM, "LTK, first key: ${firstKey.toHex()}")
+        aapsLogger.debug(LTag.PUMPBTCOMM, "First key for LTK: ${firstKey.toHex()}")
 
         val intermediateKey = ByteArray(CMAC_SIZE)
         aesCmac(firstKey, curveLTK, intermediateKey)

omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/scan/PodScanner.kt

@@ -42,7 +42,7 @@ class PodScanner(private val logger: AAPSLogger, private val bluetoothAdapter: B
     companion object {
 
         const val SCAN_FOR_SERVICE_UUID = "00004024-0000-1000-8000-00805F9B34FB"
-        const val POD_ID_NOT_ACTIVATED = 0xFFFFFFFFL
+        const val POD_ID_NOT_ACTIVATED = 0xFFFFFFFEL
         private const val SCAN_DURATION_MS = 5000
     }
 }

omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/EapAkaExchanger.kt

@@ -1,16 +1,34 @@
 package info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.session
 
+import info.nightscout.androidaps.logging.AAPSLogger
+import info.nightscout.androidaps.logging.LTag
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.Id
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.OmnipodDashBleManagerImpl
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.message.MessageIO
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.message.MessagePacket
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.pair.PairResult
-import okio.ByteString.Companion.decodeHex
+import info.nightscout.androidaps.utils.extensions.toHex
+import org.spongycastle.util.encoders.Hex
+import java.security.SecureRandom
+import javax.crypto.Cipher
+import javax.crypto.spec.SecretKeySpec
 
-class EapAkaExchanger(private val msgIO: MessageIO, private val ltk: PairResult) {
+class EapAkaExchanger(private val aapsLogger: AAPSLogger, private val msgIO: MessageIO, private val ltk: PairResult) {
 
     var seq = ltk.seq
+
+    private val controllerIV = ByteArray(IV_SIZE)
+    private var nodeIV = ByteArray(IV_SIZE)
+
     private val controllerId = Id.fromInt(OmnipodDashBleManagerImpl.CONTROLLER_ID)
+    private val sqn = byteArrayOf(0, 0, 0, 0, 0, 1)
+    private val milenage = Milenage(aapsLogger, ltk.ltk, sqn)
+
+    init {
+        aapsLogger.debug(LTag.PUMPBTCOMM, "Starting EAP-AKA")
+        val random = SecureRandom()
+        random.nextBytes(controllerIV)
+    }
 
     fun negotiateSessionKeys(): SessionKeys {
         // send EAP-AKA challenge
@@ -33,10 +51,18 @@ class EapAkaExchanger(private val msgIO: MessageIO, private val ltk: PairResult)
 
     private fun eapAkaChallenge(): EapAkaMessage {
         val payload = ByteArray(0)
+        val attributes =
+            arrayOf(
+                // TODO: verify the order or attributes
+                EapAkaAttributeRand(milenage.rand),
+                EapAkaAttributeAutn(milenage.autn),
+                EapAkaAttributeCustomIV(controllerIV),
+            )
+
         return EapAkaMessage(
             code = EapCode.REQUEST,
             identifier = 42, // TODO: find what value we need here
-            attributes =  null,
+            attributes = attributes,
             sequenceNumber = seq,
             source = controllerId,
             destination = ltk.podId,
@@ -61,10 +87,13 @@ class EapAkaExchanger(private val msgIO: MessageIO, private val ltk: PairResult)
         )
     }
 
+
     companion object {
 
-        private val MILENAGE_OP = "cdc202d5123e20f62b6d676ac72cb318".decodeHex()
+        private val MILENAGE_OP = Hex.decode("cdc202d5123e20f62b6d676ac72cb318")
-        private val MILENAGE_AMF = "b9b9".decodeHex()
+        private val MILENAGE_AMF = Hex.decode("b9b9")
-
+        private const val KEY_SIZE = 16 // 128 bits
+        private const val IV_SIZE = 4
     }
 }
+

omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/Milenage.kt

@@ -0,0 +1,94 @@
+package info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.session
+
+import info.nightscout.androidaps.logging.AAPSLogger
+import info.nightscout.androidaps.logging.LTag
+import info.nightscout.androidaps.utils.extensions.toHex
+import org.spongycastle.util.encoders.Hex
+import java.security.SecureRandom
+import javax.crypto.Cipher
+import javax.crypto.spec.SecretKeySpec
+
+class Milenage(private val aapsLogger: AAPSLogger, private val k: ByteArray, val sqn: ByteArray, val _rand: ByteArray? = null) {
+    init {
+        require(k.size == KEY_SIZE) { "Milenage key has to be $KEY_SIZE bytes long. Received: ${k.toHex()}" }
+        require(sqn.size == SEQ_SIZE) { "Milenage SEQ has to be $SEQ_SIZE long. Received: ${sqn.toHex()}" }
+    }
+
+    private val secretKeySpec = SecretKeySpec(k, "AES")
+    private val cipher: Cipher = Cipher.getInstance("AES/ECB/NoPadding")
+
+    init {
+        cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec)
+    }
+
+    val rand = _rand ?: ByteArray(KEY_SIZE)
+
+    init {
+        if (_rand == null ){
+            val random = SecureRandom()
+            random.nextBytes(rand)
+        }
+    }
+
+    private val opc = cipher.doFinal(MILENAGE_OP) xor MILENAGE_OP
+    private val rand_opc_encrypted = cipher.doFinal(rand xor opc)
+    private val rand_opc_encrypted_opc = rand_opc_encrypted xor opc
+
+    init {
+        rand_opc_encrypted_opc[15] = (rand_opc_encrypted_opc[15].toInt() xor 1).toByte()
+    }
+
+    private val res_ak = cipher.doFinal(rand_opc_encrypted_opc) xor opc
+
+    val res = res_ak.copyOfRange(8, 16)
+    val ak = res_ak.copyOfRange(0, 6)
+
+    private val ck_input = ByteArray(KEY_SIZE)
+
+    init {
+        for (i in 0..15) {
+            ck_input[(i + 12) % 16] = (rand_opc_encrypted[i].toInt() xor opc[i].toInt()).toByte()
+        }
+        ck_input[15] = (ck_input[15].toInt() xor 2).toByte()
+    }
+
+    val ck = cipher.doFinal(ck_input) xor opc
+
+    private val macAInput = ByteArray(KEY_SIZE)
+
+    init {
+        for (i in 0..15) {
+            macAInput[(i + 8) % 16] = (rand_opc_encrypted[i].toInt() xor opc[i].toInt()).toByte()
+        }
+    }
+
+    private val macAFull = cipher.doFinal(macAInput xor opc)
+    private val macA = macAFull.copyOfRange(0, 8)
+    val autn = (ak xor sqn) + MILENAGE_AMF + macA
+
+    init {
+        aapsLogger.debug(LTag.PUMPBTCOMM, "Milenage K: ${k.toHex()}")
+        aapsLogger.debug(LTag.PUMPBTCOMM, "Milenage RAND: ${rand.toHex()}")
+        aapsLogger.debug(LTag.PUMPBTCOMM, "Milenage SEQ: ${sqn.toHex()}")
+        aapsLogger.debug(LTag.PUMPBTCOMM, "Milenage CK: ${ck.toHex()}")
+        aapsLogger.debug(LTag.PUMPBTCOMM, "Milenage AUTN: ${autn.toHex()}")
+        aapsLogger.debug(LTag.PUMPBTCOMM, "Milenage RES: ${res.toHex()}")
+        aapsLogger.debug(LTag.PUMPBTCOMM, "Milenage AK: ${ak.toHex()}")
+        aapsLogger.debug(LTag.PUMPBTCOMM, "Milenage OPC: ${opc.toHex()}")
+        aapsLogger.debug(LTag.PUMPBTCOMM, "Milenage MacA: ${macA.toHex()}")
+    }
+
+    companion object {
+
+        private val MILENAGE_OP = Hex.decode("cdc202d5123e20f62b6d676ac72cb318")
+        private val MILENAGE_AMF = Hex.decode("b9b9")
+        private const val KEY_SIZE = 16
+        private const val SEQ_SIZE = 6
+    }
+}
+
+private infix fun ByteArray.xor(other: ByteArray): ByteArray {
+    val out = ByteArray(size)
+    for (i in indices) out[i] = (this[i].toInt() xor other[i].toInt()).toByte()
+    return out
+}

omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/SessionKeys.kt

@@ -1,4 +1,3 @@
 package info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.session
 
-class SessionKeys {
+class SessionKeys
-}

omnipod-dash/src/test/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/MilenageTest.kt

@@ -0,0 +1,25 @@
+package info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.session
+
+import info.nightscout.androidaps.logging.AAPSLoggerTest
+import info.nightscout.androidaps.utils.extensions.toHex
+import okio.ByteString.Companion.decodeHex
+import org.junit.Assert
+import org.junit.Assert.*
+import org.junit.Test
+import org.spongycastle.util.encoders.Hex
+
+class MilenageTest {
+
+    @Test fun testMilenage() {
+        val aapsLogger = AAPSLoggerTest()
+        val m = Milenage(
+            aapsLogger,
+            Hex.decode("c0772899720972a314f557de66d571dd"),
+            byteArrayOf(0,0,0,0,0,1),
+            Hex.decode("c2cd1248451103bd77a6c7ef88c441ba")
+        )
+        Assert.assertEquals(m.ck.toHex(), "55799fd26664cbf6e476525e2dee52c6")
+        Assert.assertEquals(m.res.toHex(), "a40bc6d13861447e")
+        Assert.assertEquals(m.autn.toHex(), "00c55c78e8d3b9b9e935860a7259f6c0")
+    }
+}