[3/n] Handle USB permission responses properly

*cough* copied CCID driver from OpenKeychains

app-common/src/main/java/im/angry/openeuicc/core/DefaultEuiccChannelFactory.kt

@@ -1,14 +1,23 @@
 package im.angry.openeuicc.core
 
 import android.content.Context
+import android.hardware.usb.UsbDevice
+import android.hardware.usb.UsbInterface
+import android.hardware.usb.UsbManager
 import android.se.omapi.SEService
 import android.util.Log
+import im.angry.openeuicc.core.usb.UsbApduInterface
+import im.angry.openeuicc.core.usb.getIoEndpoints
 import im.angry.openeuicc.util.*
 import java.lang.IllegalArgumentException
 
 open class DefaultEuiccChannelFactory(protected val context: Context) : EuiccChannelFactory {
     private var seService: SEService? = null
 
+    private val usbManager by lazy {
+        context.getSystemService(Context.USB_SERVICE) as UsbManager
+    }
+
     private suspend fun ensureSEService() {
         if (seService == null || !seService!!.isConnected) {
             seService = connectSEService(context)
@@ -36,6 +45,17 @@ open class DefaultEuiccChannelFactory(protected val context: Context) : EuiccCha
         return null
     }
 
+    override fun tryOpenUsbEuiccChannel(usbDevice: UsbDevice, usbInterface: UsbInterface): EuiccChannel? {
+        val (bulkIn, bulkOut) = usbInterface.getIoEndpoints()
+        if (bulkIn == null || bulkOut == null) return null
+        val conn = usbManager.openDevice(usbDevice) ?: return null
+        if (!conn.claimInterface(usbInterface, true)) return null
+        return EuiccChannel(
+            FakeUiccPortInfoCompat(FakeUiccCardInfoCompat(EuiccChannelManager.USB_CHANNEL_ID)),
+            UsbApduInterface(conn, bulkIn, bulkOut)
+        )
+    }
+
     override fun cleanup() {
         seService?.shutdown()
         seService = null

app-common/src/main/java/im/angry/openeuicc/core/DefaultEuiccChannelManager.kt

@@ -1,8 +1,11 @@
 package im.angry.openeuicc.core
 
 import android.content.Context
+import android.hardware.usb.UsbDevice
+import android.hardware.usb.UsbManager
 import android.telephony.SubscriptionManager
 import android.util.Log
+import im.angry.openeuicc.core.usb.getSmartCardInterface
 import im.angry.openeuicc.di.AppContainer
 import im.angry.openeuicc.util.*
 import kotlinx.coroutines.Dispatchers
@@ -23,12 +26,18 @@ open class DefaultEuiccChannelManager(
 
     private val channelCache = mutableListOf<EuiccChannel>()
 
+    private var usbChannel: EuiccChannel? = null
+
     private val lock = Mutex()
 
     protected val tm by lazy {
         appContainer.telephonyManager
     }
 
+    private val usbManager by lazy {
+        context.getSystemService(Context.USB_SERVICE) as UsbManager
+    }
+
     private val euiccChannelFactory by lazy {
         appContainer.euiccChannelFactory
     }
@@ -38,6 +47,15 @@ open class DefaultEuiccChannelManager(
 
     private suspend fun tryOpenEuiccChannel(port: UiccPortInfoCompat): EuiccChannel? {
         lock.withLock {
+            if (port.card.physicalSlotIndex == EuiccChannelManager.USB_CHANNEL_ID) {
+                return if (usbChannel != null && usbChannel!!.valid) {
+                    usbChannel
+                } else {
+                    usbChannel = null
+                    null
+                }
+            }
+
             val existing =
                 channelCache.find { it.slotId == port.card.physicalSlotIndex && it.portId == port.portIndex }
             if (existing != null) {
@@ -73,6 +91,10 @@ open class DefaultEuiccChannelManager(
     override fun findEuiccChannelBySlotBlocking(logicalSlotId: Int): EuiccChannel? =
         runBlocking {
             withContext(Dispatchers.IO) {
+                if (logicalSlotId == EuiccChannelManager.USB_CHANNEL_ID) {
+                    return@withContext usbChannel
+                }
+
                 for (card in uiccCards) {
                     for (port in card.ports) {
                         if (port.logicalSlotIndex == logicalSlotId) {
@@ -88,6 +110,10 @@ open class DefaultEuiccChannelManager(
     override fun findEuiccChannelByPhysicalSlotBlocking(physicalSlotId: Int): EuiccChannel? =
         runBlocking {
             withContext(Dispatchers.IO) {
+                if (physicalSlotId == EuiccChannelManager.USB_CHANNEL_ID) {
+                    return@withContext usbChannel
+                }
+
                 for (card in uiccCards) {
                     if (card.physicalSlotIndex != physicalSlotId) continue
                     for (port in card.ports) {
@@ -100,6 +126,10 @@ open class DefaultEuiccChannelManager(
         }
 
     override suspend fun findAllEuiccChannelsByPhysicalSlot(physicalSlotId: Int): List<EuiccChannel>? {
+        if (physicalSlotId == EuiccChannelManager.USB_CHANNEL_ID) {
+            return usbChannel?.let { listOf(it) }
+        }
+
         for (card in uiccCards) {
             if (card.physicalSlotIndex != physicalSlotId) continue
             return card.ports.mapNotNull { tryOpenEuiccChannel(it) }
@@ -115,6 +145,10 @@ open class DefaultEuiccChannelManager(
 
     override suspend fun findEuiccChannelByPort(physicalSlotId: Int, portId: Int): EuiccChannel? =
         withContext(Dispatchers.IO) {
+            if (physicalSlotId == EuiccChannelManager.USB_CHANNEL_ID) {
+                return@withContext usbChannel
+            }
+
             uiccCards.find { it.physicalSlotIndex == physicalSlotId }?.let { card ->
                 card.ports.find { it.portIndex == portId }?.let { tryOpenEuiccChannel(it) }
             }
@@ -162,11 +196,37 @@ open class DefaultEuiccChannelManager(
             }
         }
 
+    override suspend fun enumerateUsbEuiccChannel(): Pair<UsbDevice?, EuiccChannel?> =
+        withContext(Dispatchers.IO) {
+            usbManager.deviceList.values.forEach { device ->
+                Log.i(TAG, "Scanning USB device ${device.deviceId}:${device.vendorId}")
+                val iface = device.getSmartCardInterface() ?: return@forEach
+                // If we don't have permission, tell UI code that we found a candidate device, but we
+                // need permission to be able to do anything with it
+                if (!usbManager.hasPermission(device)) return@withContext Pair(device, null)
+                Log.i(TAG, "Found CCID interface on ${device.deviceId}:${device.vendorId}, and has permission; trying to open channel")
+                try {
+                    val channel = euiccChannelFactory.tryOpenUsbEuiccChannel(device, iface)
+                    if (channel != null && channel.lpa.valid) {
+                        usbChannel = channel
+                        return@withContext Pair(device, channel)
+                    }
+                } catch (e: Exception) {
+                    // Ignored -- skip forward
+                    e.printStackTrace()
+                }
+                Log.i(TAG, "No valid eUICC channel found on USB device ${device.deviceId}:${device.vendorId}")
+            }
+            return@withContext Pair(null, null)
+        }
+
     override fun invalidate() {
         for (channel in channelCache) {
             channel.close()
         }
 
+        usbChannel?.close()
+        usbChannel = null
         channelCache.clear()
         euiccChannelFactory.cleanup()
     }

app-common/src/main/java/im/angry/openeuicc/core/EuiccChannelFactory.kt

@@ -1,5 +1,7 @@
 package im.angry.openeuicc.core
 
+import android.hardware.usb.UsbDevice
+import android.hardware.usb.UsbInterface
 import im.angry.openeuicc.util.*
 
 // This class is here instead of inside DI because it contains a bit more logic than just
@@ -7,6 +9,8 @@ import im.angry.openeuicc.util.*
 interface EuiccChannelFactory {
     suspend fun tryOpenEuiccChannel(port: UiccPortInfoCompat): EuiccChannel?
 
+    fun tryOpenUsbEuiccChannel(usbDevice: UsbDevice, usbInterface: UsbInterface): EuiccChannel?
+
     /**
      * Release all resources used by this EuiccChannelFactory
      * Note that the same instance may be reused; any resources allocated must be automatically

app-common/src/main/java/im/angry/openeuicc/core/EuiccChannelManager.kt

@@ -1,5 +1,7 @@
 package im.angry.openeuicc.core
 
+import android.hardware.usb.UsbDevice
+
 /**
  * EuiccChannelManager holds references to, and manages the lifecycles of, individual
  * APDU channels to SIM cards. The find* methods will create channels when needed, and
@@ -11,13 +13,25 @@ package im.angry.openeuicc.core
  * Holding references independent of EuiccChannelManagerService is unsupported.
  */
 interface EuiccChannelManager {
+    companion object {
+        const val USB_CHANNEL_ID = 99
+    }
+
     /**
-     * Scan all possible sources for EuiccChannels, return them and have all
+     * Scan all possible _device internal_ sources for EuiccChannels, return them and have all
      * scanned channels cached; these channels will remain open for the entire lifetime of
      * this EuiccChannelManager object, unless disconnected externally or invalidate()'d
      */
     suspend fun enumerateEuiccChannels(): List<EuiccChannel>
 
+    /**
+     * Scan all possible USB devices for CCID readers that may contain eUICC cards.
+     * If found, try to open it for access, and add it to the internal EuiccChannel cache
+     * as a "port" with id 99. When user interaction is required to obtain permission
+     * to interact with the device, the second return value (EuiccChannel) will be null.
+     */
+    suspend fun enumerateUsbEuiccChannel(): Pair<UsbDevice?, EuiccChannel?>
+
     /**
      * Wait for a slot + port to reconnect (i.e. become valid again)
      * If the port is currently valid, this function will return immediately.

app-common/src/main/java/im/angry/openeuicc/core/usb/UsbApduInterface.kt

@@ -0,0 +1,159 @@
+package im.angry.openeuicc.core.usb
+
+import android.hardware.usb.UsbDeviceConnection
+import android.hardware.usb.UsbEndpoint
+import android.util.Log
+import im.angry.openeuicc.util.*
+import net.typeblog.lpac_jni.ApduInterface
+
+class UsbApduInterface(
+    private val conn: UsbDeviceConnection,
+    private val bulkIn: UsbEndpoint,
+    private val bulkOut: UsbEndpoint
+): ApduInterface {
+    companion object {
+        private const val TAG = "UsbApduInterface"
+    }
+
+    private lateinit var ccidDescription: UsbCcidDescription
+    private lateinit var transceiver: UsbCcidTransceiver
+
+    private var channelId = -1
+
+    override fun connect() {
+        ccidDescription = UsbCcidDescription.fromRawDescriptors(conn.rawDescriptors)!!
+
+        if (!ccidDescription.hasT0Protocol) {
+            throw IllegalArgumentException("Unsupported card reader; T=0 support is required")
+        }
+
+        transceiver = UsbCcidTransceiver(conn, bulkIn, bulkOut, ccidDescription)
+
+        try {
+            transceiver.iccPowerOn()
+        } catch (e: Exception) {
+            e.printStackTrace()
+            throw e
+        }
+    }
+
+    override fun disconnect() {
+        conn.close()
+    }
+
+    override fun logicalChannelOpen(aid: ByteArray): Int {
+        check(channelId == -1) { "Logical channel already opened" }
+
+        // OPEN LOGICAL CHANNEL
+        val req = manageChannelCmd(true, 0)
+        Log.d(TAG, "OPEN LOGICAL CHANNEL: ${req.encodeHex()}")
+
+        val resp = try {
+            transmitApduByChannel(req, 0)
+        } catch (e: Exception) {
+            e.printStackTrace()
+            return -1
+        }
+        Log.d(TAG, "OPEN LOGICAL CHANNEL response: ${resp.encodeHex()}")
+
+        return if (resp.size >= 2 && resp.sliceArray((resp.size - 2) until resp.size).contentEquals(
+                byteArrayOf(0x90.toByte(), 0x00)
+            )
+        ) {
+            channelId = resp[0].toInt()
+            Log.d(TAG, "channelId = $channelId")
+
+            // Then, select AID
+            val selectAid = selectByDfCmd(aid, channelId.toByte())
+            Log.d(TAG, "Select DF command: ${selectAid.encodeHex()}")
+            val selectAidResp = transmitApduByChannel(selectAid, channelId.toByte())
+            Log.d(TAG, "Select DF resp: ${selectAidResp.encodeHex()}")
+            channelId
+        } else {
+            -1
+        }
+    }
+
+    override fun logicalChannelClose(handle: Int) {
+        check(handle == channelId) { "Logical channel ID mismatch" }
+        check(channelId != -1) { "Logical channel is not opened" }
+
+        // CLOSE LOGICAL CHANNEL
+        val req = manageChannelCmd(false, channelId.toByte())
+        Log.d(TAG, "CLOSE LOGICAL CHANNEL: ${req.encodeHex()}")
+
+        val resp = transmitApduByChannel(req, channelId.toByte())
+        Log.d(TAG, "CLOSE LOGICAL CHANNEL response: ${resp.encodeHex()}")
+
+        channelId = -1
+    }
+
+    override fun transmit(tx: ByteArray): ByteArray {
+        check(channelId != -1) { "Logical channel is not opened" }
+        Log.d(TAG, "USB APDU command: ${tx.encodeHex()}")
+        val resp = transmitApduByChannel(tx, channelId.toByte())
+        Log.d(TAG, "USB APDU response: ${resp.encodeHex()}")
+        return resp
+    }
+
+    override val valid: Boolean
+        get() = true
+
+    private fun buildCmd(cla: Byte, ins: Byte, p1: Byte, p2: Byte, data: ByteArray?, le: Byte?) =
+        byteArrayOf(cla, ins, p1, p2).let {
+            if (data != null) {
+                it + data.size.toByte() + data
+            } else {
+                it
+            }
+        }.let {
+            if (le != null) {
+                it + byteArrayOf(le)
+            } else {
+                it
+            }
+        }
+
+    private fun manageChannelCmd(open: Boolean, channel: Byte) =
+        if (open) {
+            buildCmd(0x00, 0x70, 0x00, 0x00, null, 0x01)
+        } else {
+            buildCmd(channel, 0x70, 0x80.toByte(), channel, null, null)
+        }
+
+    private fun selectByDfCmd(aid: ByteArray, channel: Byte) =
+        buildCmd(channel, 0xA4.toByte(), 0x04, 0x00, aid, null)
+
+    private fun transmitApduByChannel(tx: ByteArray, channel: Byte): ByteArray {
+        val realTx = tx.copyOf()
+        // OR the channel mask into the CLA byte
+        realTx[0] = ((realTx[0].toInt() and 0xFC) or channel.toInt()).toByte()
+
+        var resp = transceiver.sendXfrBlock(realTx)!!.data!!
+
+        if (resp.size >= 2) {
+            var sw1 = resp[resp.size - 2].toInt() and 0xFF
+            var sw2 = resp[resp.size - 1].toInt() and 0xFF
+
+            if (sw1 == 0x6C) {
+                realTx[realTx.size - 1] = resp[resp.size - 1]
+                resp = transceiver.sendXfrBlock(realTx)!!.data!!
+            } else if (sw1 == 0x61) {
+                do {
+                    val getResponseCmd = byteArrayOf(
+                        realTx[0], 0xC0.toByte(), 0x00, 0x00, sw2.toByte()
+                    )
+
+                    val tmp = transceiver.sendXfrBlock(getResponseCmd)!!.data!!
+
+                    resp = resp.sliceArray(0 until (resp.size - 2)) + tmp
+
+                    sw1 = resp[resp.size - 2].toInt() and 0xFF
+                    sw2 = resp[resp.size - 1].toInt() and 0xFF
+                } while (sw1 == 0x61)
+            }
+        }
+
+        return resp
+    }
+}

app-common/src/main/java/im/angry/openeuicc/core/usb/UsbCcidDescription.kt

@@ -0,0 +1,104 @@
+package im.angry.openeuicc.core.usb
+
+import java.nio.ByteBuffer
+import java.nio.ByteOrder
+
+data class UsbCcidDescription(
+    private val bMaxSlotIndex: Byte,
+    private val bVoltageSupport: Byte,
+    private val dwProtocols: Int,
+    private val dwFeatures: Int
+) {
+    companion object {
+        private const val DESCRIPTOR_LENGTH: Byte = 0x36
+        private const val DESCRIPTOR_TYPE: Byte = 0x21
+
+        // dwFeatures Masks
+        private const val FEATURE_AUTOMATIC_VOLTAGE = 0x00008
+        private const val FEATURE_AUTOMATIC_PPS = 0x00080
+
+        private const val FEATURE_EXCHANGE_LEVEL_TPDU = 0x10000
+        private const val FEATURE_EXCHANGE_LEVEL_SHORT_APDU = 0x20000
+        private const val FEATURE_EXCHAGE_LEVEL_EXTENDED_APDU = 0x40000
+
+        // bVoltageSupport Masks
+        private const val VOLTAGE_5V: Byte = 1
+        private const val VOLTAGE_3V: Byte = 2
+        private const val VOLTAGE_1_8V: Byte = 4
+
+        private const val SLOT_OFFSET = 4
+        private const val FEATURES_OFFSET = 40
+        private const val MASK_T0_PROTO = 1
+        private const val MASK_T1_PROTO = 2
+
+        fun fromRawDescriptors(desc: ByteArray): UsbCcidDescription? {
+            var dwProtocols = 0
+            var dwFeatures = 0
+            var bMaxSlotIndex: Byte = 0
+            var bVoltageSupport: Byte = 0
+
+            var hasCcidDescriptor = false
+
+            val byteBuffer = ByteBuffer.wrap(desc).order(ByteOrder.LITTLE_ENDIAN)
+
+            while (byteBuffer.hasRemaining()) {
+                byteBuffer.mark()
+                val len = byteBuffer.get()
+                val type = byteBuffer.get()
+                if (type == DESCRIPTOR_TYPE && len == DESCRIPTOR_LENGTH) {
+                    byteBuffer.reset()
+                    byteBuffer.position(byteBuffer.position() + SLOT_OFFSET)
+                    bMaxSlotIndex = byteBuffer.get()
+                    bVoltageSupport = byteBuffer.get()
+                    dwProtocols = byteBuffer.int
+                    byteBuffer.reset()
+                    byteBuffer.position(byteBuffer.position() + FEATURES_OFFSET)
+                    dwFeatures = byteBuffer.int
+                    hasCcidDescriptor = true
+                    break
+                } else {
+                    byteBuffer.position(byteBuffer.position() + len - 2)
+                }
+            }
+
+            return if (hasCcidDescriptor) {
+                UsbCcidDescription(bMaxSlotIndex, bVoltageSupport, dwProtocols, dwFeatures)
+            } else {
+                null
+            }
+        }
+    }
+
+    enum class Voltage(powerOnValue: Int, mask: Int) {
+        AUTO(0, 0), _5V(1, VOLTAGE_5V.toInt()), _3V(2, VOLTAGE_3V.toInt()), _1_8V(
+            3,
+            VOLTAGE_1_8V.toInt()
+        );
+
+        val mask = powerOnValue.toByte()
+        val powerOnValue = mask.toByte()
+    }
+
+    private fun hasFeature(feature: Int): Boolean =
+        (dwFeatures and feature) != 0
+
+    val voltages: Array<Voltage>
+        get() =
+            if (hasFeature(FEATURE_AUTOMATIC_VOLTAGE)) {
+                arrayOf(Voltage.AUTO)
+            } else {
+                Voltage.values().mapNotNull {
+                    if ((it.mask.toInt() and bVoltageSupport.toInt()) != 0) {
+                        it
+                    } else {
+                        null
+                    }
+                }.toTypedArray()
+            }
+
+    val hasAutomaticPps: Boolean
+        get() = hasFeature(FEATURE_AUTOMATIC_PPS)
+
+    val hasT0Protocol: Boolean
+        get() = (dwProtocols and MASK_T0_PROTO) != 0
+}

app-common/src/main/java/im/angry/openeuicc/core/usb/UsbCcidTransceiver.kt

@@ -0,0 +1,348 @@
+package im.angry.openeuicc.core.usb
+
+import android.hardware.usb.UsbDeviceConnection
+import android.hardware.usb.UsbEndpoint
+import android.os.SystemClock
+import android.util.Log
+import im.angry.openeuicc.util.*
+import java.nio.ByteBuffer
+import java.nio.ByteOrder
+
+
+/**
+ * Provides raw, APDU-agnostic transmission to the CCID reader
+ * Adapted from <https://github.com/open-keychain/open-keychain/blob/master/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb/CcidTransceiver.java>
+ */
+class UsbCcidTransceiver(
+    private val usbConnection: UsbDeviceConnection,
+    private val usbBulkIn: UsbEndpoint,
+    private val usbBulkOut: UsbEndpoint,
+    private val usbCcidDescription: UsbCcidDescription
+) {
+    companion object {
+        private const val TAG = "UsbCcidTransceiver"
+
+        private const val CCID_HEADER_LENGTH = 10
+
+        private const val MESSAGE_TYPE_RDR_TO_PC_DATA_BLOCK = 0x80
+        private const val MESSAGE_TYPE_PC_TO_RDR_ICC_POWER_ON = 0x62
+        private const val MESSAGE_TYPE_PC_TO_RDR_ICC_POWER_OFF = 0x63
+        private const val MESSAGE_TYPE_PC_TO_RDR_XFR_BLOCK = 0x6f
+
+        private const val COMMAND_STATUS_SUCCESS: Byte = 0
+        private const val COMMAND_STATUS_TIME_EXTENSION_RQUESTED: Byte = 2
+
+        /**
+         * Level Parameter: APDU is a single command.
+         *
+         * "the command APDU begins and ends with this command"
+         * -- DWG Smart-Card USB Integrated Circuit(s) Card Devices rev 1.0
+         * § 6.1.1.3
+         */
+        const val LEVEL_PARAM_START_SINGLE_CMD_APDU: Short = 0x0000
+
+        /**
+         * Level Parameter: First APDU in a multi-command APDU.
+         *
+         * "the command APDU begins with this command, and continue in the
+         * next PC_to_RDR_XfrBlock"
+         * -- DWG Smart-Card USB Integrated Circuit(s) Card Devices rev 1.0
+         * § 6.1.1.3
+         */
+        const val LEVEL_PARAM_START_MULTI_CMD_APDU: Short = 0x0001
+
+        /**
+         * Level Parameter: Final APDU in a multi-command APDU.
+         *
+         * "this abData field continues a command APDU and ends the command APDU"
+         * -- DWG Smart-Card USB Integrated Circuit(s) Card Devices rev 1.0
+         * § 6.1.1.3
+         */
+        const val LEVEL_PARAM_END_MULTI_CMD_APDU: Short = 0x0002
+
+        /**
+         * Level Parameter: Next command in a multi-command APDU.
+         *
+         * "the abData field continues a command APDU and another block is to follow"
+         * -- DWG Smart-Card USB Integrated Circuit(s) Card Devices rev 1.0
+         * § 6.1.1.3
+         */
+        const val LEVEL_PARAM_CONTINUE_MULTI_CMD_APDU: Short = 0x0003
+
+        /**
+         * Level Parameter: Request the device continue sending APDU.
+         *
+         * "empty abData field, continuation of response APDU is expected in the next
+         * RDR_to_PC_DataBlock"
+         * -- DWG Smart-Card USB Integrated Circuit(s) Card Devices rev 1.0
+         * § 6.1.1.3
+         */
+        const val LEVEL_PARAM_CONTINUE_RESPONSE: Short = 0x0010
+
+        private const val SLOT_NUMBER = 0x00
+
+        private const val ICC_STATUS_SUCCESS: Byte = 0
+
+        private const val DEVICE_COMMUNICATE_TIMEOUT_MILLIS = 5000
+        private const val DEVICE_SKIP_TIMEOUT_MILLIS = 100
+    }
+
+    data class UsbCcidErrorException(val msg: String, val errorResponse: CcidDataBlock) :
+        Exception(msg)
+
+    data class CcidDataBlock(
+        val dwLength: Int,
+        val bSlot: Byte,
+        val bSeq: Byte,
+        val bStatus: Byte,
+        val bError: Byte,
+        val bChainParameter: Byte,
+        val data: ByteArray?
+    ) {
+        companion object {
+            fun parseHeaderFromBytes(headerBytes: ByteArray): CcidDataBlock {
+                val buf = ByteBuffer.wrap(headerBytes)
+                buf.order(ByteOrder.LITTLE_ENDIAN)
+
+                val type = buf.get()
+                require(type == MESSAGE_TYPE_RDR_TO_PC_DATA_BLOCK.toByte()) { "Header has incorrect type value!" }
+                val dwLength = buf.int
+                val bSlot = buf.get()
+                val bSeq = buf.get()
+                val bStatus = buf.get()
+                val bError = buf.get()
+                val bChainParameter = buf.get()
+
+                return CcidDataBlock(dwLength, bSlot, bSeq, bStatus, bError, bChainParameter, null)
+            }
+        }
+
+        fun withData(d: ByteArray): CcidDataBlock {
+            require(data == null) { "Cannot add data twice" }
+            return CcidDataBlock(dwLength, bSlot, bSeq, bStatus, bError, bChainParameter, d)
+        }
+
+        val iccStatus: Byte
+            get() = (bStatus.toInt() and 0x03).toByte()
+
+        val commandStatus: Byte
+            get() = ((bStatus.toInt() shr 6) and 0x03).toByte()
+
+        val isStatusTimeoutExtensionRequest: Boolean
+            get() = commandStatus == COMMAND_STATUS_TIME_EXTENSION_RQUESTED
+
+        val isStatusSuccess: Boolean
+            get() = iccStatus == ICC_STATUS_SUCCESS && commandStatus == COMMAND_STATUS_SUCCESS
+    }
+
+    val hasAutomaticPps = usbCcidDescription.hasAutomaticPps
+
+    private val inputBuffer = ByteArray(usbBulkIn.maxPacketSize)
+
+    private var currentSequenceNumber: Byte = 0
+
+    private fun sendRaw(data: ByteArray, offset: Int, length: Int) {
+        val tr1 = usbConnection.bulkTransfer(
+            usbBulkOut, data, offset, length, DEVICE_COMMUNICATE_TIMEOUT_MILLIS
+        )
+        if (tr1 != length) {
+            throw UsbTransportException(
+                "USB error - failed to transmit data ($tr1/$length)"
+            )
+        }
+    }
+
+    private fun receiveDataBlock(expectedSequenceNumber: Byte): CcidDataBlock? {
+        var response: CcidDataBlock?
+        do {
+            response = receiveDataBlockImmediate(expectedSequenceNumber)
+        } while (response!!.isStatusTimeoutExtensionRequest)
+        if (!response.isStatusSuccess) {
+            throw UsbCcidErrorException("USB-CCID error!", response)
+        }
+        return response
+    }
+
+    private fun receiveDataBlockImmediate(expectedSequenceNumber: Byte): CcidDataBlock? {
+        /*
+         * Some USB CCID devices (notably NitroKey 3) may time-out and need a subsequent poke to
+         * carry on communications.  No particular reason why the number 3 was chosen.  If we get a
+         * zero-sized reply (or a time-out), we try again.  Clamped retries prevent an infinite loop
+         * if things really turn sour.
+         */
+        var attempts = 3
+        Log.d(TAG, "Receive data block immediate seq=$expectedSequenceNumber")
+        var readBytes: Int
+        do {
+            readBytes = usbConnection.bulkTransfer(
+                usbBulkIn, inputBuffer, inputBuffer.size, DEVICE_COMMUNICATE_TIMEOUT_MILLIS
+            )
+            Log.d(TAG, "Received " + readBytes + " bytes: " + inputBuffer.encodeHex())
+        } while (readBytes <= 0 && attempts-- > 0)
+        if (readBytes < CCID_HEADER_LENGTH) {
+            throw UsbTransportException("USB-CCID error - failed to receive CCID header")
+        }
+        if (inputBuffer[0] != MESSAGE_TYPE_RDR_TO_PC_DATA_BLOCK.toByte()) {
+            if (expectedSequenceNumber != inputBuffer[6]) {
+                throw UsbTransportException(
+                    ((("USB-CCID error - bad CCID header, type " + inputBuffer[0]) + " (expected " +
+                            MESSAGE_TYPE_RDR_TO_PC_DATA_BLOCK) + "), sequence number " + inputBuffer[6]
+                            ) + " (expected " +
+                            expectedSequenceNumber + ")"
+                )
+            }
+            throw UsbTransportException(
+                "USB-CCID error - bad CCID header type " + inputBuffer[0]
+            )
+        }
+        var result = CcidDataBlock.parseHeaderFromBytes(inputBuffer)
+        if (expectedSequenceNumber != result.bSeq) {
+            throw UsbTransportException(
+                ("USB-CCID error - expected sequence number " +
+                        expectedSequenceNumber + ", got " + result)
+            )
+        }
+
+        val dataBuffer = ByteArray(result.dwLength)
+        var bufferedBytes = readBytes - CCID_HEADER_LENGTH
+        System.arraycopy(inputBuffer, CCID_HEADER_LENGTH, dataBuffer, 0, bufferedBytes)
+        while (bufferedBytes < dataBuffer.size) {
+            readBytes = usbConnection.bulkTransfer(
+                usbBulkIn, inputBuffer, inputBuffer.size, DEVICE_COMMUNICATE_TIMEOUT_MILLIS
+            )
+            if (readBytes < 0) {
+                throw UsbTransportException(
+                    "USB error - failed reading response data! Header: $result"
+                )
+            }
+            System.arraycopy(inputBuffer, 0, dataBuffer, bufferedBytes, readBytes)
+            bufferedBytes += readBytes
+        }
+        result = result.withData(dataBuffer)
+        return result
+    }
+
+
+    private fun skipAvailableInput() {
+        var ignoredBytes: Int
+        do {
+            ignoredBytes = usbConnection.bulkTransfer(
+                usbBulkIn, inputBuffer, inputBuffer.size, DEVICE_SKIP_TIMEOUT_MILLIS
+            )
+            if (ignoredBytes > 0) {
+                Log.e(TAG, "Skipped $ignoredBytes bytes")
+            }
+        } while (ignoredBytes > 0)
+    }
+
+    /**
+     * Transmits XfrBlock
+     * 6.1.4 PC_to_RDR_XfrBlock
+     *
+     * @param payload payload to transmit
+     */
+    fun sendXfrBlock(payload: ByteArray): CcidDataBlock? {
+        return sendXfrBlock(payload, LEVEL_PARAM_START_SINGLE_CMD_APDU)
+    }
+
+    /**
+     * Receives a continued XfrBlock. Should be called when a multiblock response is indicated
+     * 6.1.4 PC_to_RDR_XfrBlock
+     */
+    fun receiveContinuedResponse(): CcidDataBlock? {
+        return sendXfrBlock(ByteArray(0), LEVEL_PARAM_CONTINUE_RESPONSE)
+    }
+
+    /**
+     * Transmits XfrBlock
+     * 6.1.4 PC_to_RDR_XfrBlock
+     *
+     * @param payload payload to transmit
+     * @param levelParam Level parameter
+     */
+    private fun sendXfrBlock(payload: ByteArray, levelParam: Short): CcidDataBlock? {
+        val startTime = SystemClock.elapsedRealtime()
+        val l = payload.size
+        val sequenceNumber: Byte = currentSequenceNumber++
+        val headerData = byteArrayOf(
+            MESSAGE_TYPE_PC_TO_RDR_XFR_BLOCK.toByte(),
+            l.toByte(),
+            (l shr 8).toByte(),
+            (l shr 16).toByte(),
+            (l shr 24).toByte(),
+            SLOT_NUMBER.toByte(),
+            sequenceNumber,
+            0x00.toByte(),
+            (levelParam.toInt() and 0x00ff).toByte(),
+            (levelParam.toInt() shr 8).toByte()
+        )
+        val data: ByteArray = headerData + payload
+        var sentBytes = 0
+        while (sentBytes < data.size) {
+            val bytesToSend = Math.min(usbBulkOut.maxPacketSize, data.size - sentBytes)
+            sendRaw(data, sentBytes, bytesToSend)
+            sentBytes += bytesToSend
+        }
+        val ccidDataBlock = receiveDataBlock(sequenceNumber)
+        val elapsedTime = SystemClock.elapsedRealtime() - startTime
+        Log.d(TAG, "USB XferBlock call took " + elapsedTime + "ms")
+        return ccidDataBlock
+    }
+
+    fun iccPowerOn(): CcidDataBlock {
+        val startTime = SystemClock.elapsedRealtime()
+        skipAvailableInput()
+        var response: CcidDataBlock? = null
+        for (v in usbCcidDescription.voltages) {
+            Log.v(TAG, "CCID: attempting to power on with voltage $v")
+            response = try {
+                iccPowerOnVoltage(v.powerOnValue)
+            } catch (e: UsbCcidErrorException) {
+                if (e.errorResponse.bError.toInt() == 7) { // Power select error
+                    Log.v(TAG, "CCID: failed to power on with voltage $v")
+                    iccPowerOff()
+                    Log.v(TAG, "CCID: powered off")
+                    continue
+                }
+                throw e
+            }
+            break
+        }
+        if (response == null) {
+            throw UsbTransportException("Couldn't power up ICC2")
+        }
+        val elapsedTime = SystemClock.elapsedRealtime() - startTime
+        Log.d(
+            TAG,
+            "Usb transport connected, took " + elapsedTime + "ms, ATR=" +
+                    response.data?.encodeHex()
+        )
+        return response
+    }
+
+    private fun iccPowerOnVoltage(voltage: Byte): CcidDataBlock? {
+        val sequenceNumber = currentSequenceNumber++
+        val iccPowerCommand = byteArrayOf(
+            MESSAGE_TYPE_PC_TO_RDR_ICC_POWER_ON.toByte(),
+            0x00, 0x00, 0x00, 0x00,
+            SLOT_NUMBER.toByte(),
+            sequenceNumber,
+            voltage,
+            0x00, 0x00 // reserved for future use
+        )
+        sendRaw(iccPowerCommand, 0, iccPowerCommand.size)
+        return receiveDataBlock(sequenceNumber)
+    }
+
+    private fun iccPowerOff() {
+        val sequenceNumber = currentSequenceNumber++
+        val iccPowerCommand = byteArrayOf(
+            MESSAGE_TYPE_PC_TO_RDR_ICC_POWER_OFF.toByte(),
+            0x00, 0x00, 0x00, 0x00,
+            0x00,
+            sequenceNumber,
+            0x00
+        )
+        sendRaw(iccPowerCommand, 0, iccPowerCommand.size)
+    }
+}

app-common/src/main/java/im/angry/openeuicc/core/usb/UsbCcidUtils.kt

@@ -0,0 +1,36 @@
+// Adapted from <https://github.com/open-keychain/open-keychain/blob/master/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/usb>
+package im.angry.openeuicc.core.usb
+
+import android.hardware.usb.UsbConstants
+import android.hardware.usb.UsbDevice
+import android.hardware.usb.UsbEndpoint
+import android.hardware.usb.UsbInterface
+
+class UsbTransportException(msg: String) : Exception(msg)
+
+fun UsbInterface.getIoEndpoints(): Pair<UsbEndpoint?, UsbEndpoint?> {
+    var bulkIn: UsbEndpoint? = null
+    var bulkOut: UsbEndpoint? = null
+    for (i in 0 until endpointCount) {
+        val endpoint = getEndpoint(i)
+        if (endpoint.type != UsbConstants.USB_ENDPOINT_XFER_BULK) {
+            continue
+        }
+        if (endpoint.direction == UsbConstants.USB_DIR_IN) {
+            bulkIn = endpoint
+        } else if (endpoint.direction == UsbConstants.USB_DIR_OUT) {
+            bulkOut = endpoint
+        }
+    }
+    return Pair(bulkIn, bulkOut)
+}
+
+fun UsbDevice.getSmartCardInterface(): UsbInterface? {
+    for (i in 0 until interfaceCount) {
+        val anInterface = getInterface(i)
+        if (anInterface.interfaceClass == UsbConstants.USB_CLASS_CSCID) {
+            return anInterface
+        }
+    }
+    return null
+}

app-common/src/main/java/im/angry/openeuicc/ui/MainActivity.kt

@@ -1,6 +1,14 @@
 package im.angry.openeuicc.ui
 
+import android.annotation.SuppressLint
+import android.app.PendingIntent
+import android.content.BroadcastReceiver
+import android.content.Context
 import android.content.Intent
+import android.content.IntentFilter
+import android.hardware.usb.UsbDevice
+import android.hardware.usb.UsbManager
+import android.os.Build
 import android.os.Bundle
 import android.telephony.TelephonyManager
 import android.util.Log
@@ -12,6 +20,7 @@ import android.widget.ArrayAdapter
 import android.widget.Spinner
 import androidx.lifecycle.lifecycleScope
 import im.angry.openeuicc.common.R
+import im.angry.openeuicc.core.EuiccChannel
 import im.angry.openeuicc.util.*
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
@@ -20,6 +29,7 @@ import kotlinx.coroutines.withContext
 open class MainActivity : BaseEuiccAccessActivity(), OpenEuiccContextMarker {
     companion object {
         const val TAG = "MainActivity"
+        const val ACTION_USB_PERMISSION = "im.angry.openeuicc.USB_PERMISSION"
     }
 
     private lateinit var spinnerAdapter: ArrayAdapter<String>
@@ -30,6 +40,28 @@ open class MainActivity : BaseEuiccAccessActivity(), OpenEuiccContextMarker {
 
     protected lateinit var tm: TelephonyManager
 
+    private val usbManager: UsbManager by lazy {
+        getSystemService(USB_SERVICE) as UsbManager
+    }
+
+    private var usbDevice: UsbDevice? = null
+    private var usbChannel: EuiccChannel? = null
+
+    private lateinit var usbPendingIntent: PendingIntent
+
+    private val usbPermissionReceiver = object : BroadcastReceiver() {
+        override fun onReceive(context: Context?, intent: Intent?) {
+            if (intent?.action == ACTION_USB_PERMISSION) {
+                if (usbDevice != null && usbManager.hasPermission(usbDevice)) {
+                    lifecycleScope.launch(Dispatchers.Main) {
+                        switchToUsbFragmentIfPossible()
+                    }
+                }
+            }
+        }
+    }
+
+    @SuppressLint("WrongConstant", "UnspecifiedRegisterReceiverFlag")
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
@@ -43,6 +75,15 @@ open class MainActivity : BaseEuiccAccessActivity(), OpenEuiccContextMarker {
         tm = telephonyManager
 
         spinnerAdapter = ArrayAdapter<String>(this, R.layout.spinner_item)
+
+        usbPendingIntent = PendingIntent.getBroadcast(this, 0,
+            Intent(ACTION_USB_PERMISSION), PendingIntent.FLAG_IMMUTABLE)
+        val filter = IntentFilter(ACTION_USB_PERMISSION)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+            registerReceiver(usbPermissionReceiver, filter, Context.RECEIVER_EXPORTED)
+        } else {
+            registerReceiver(usbPermissionReceiver, filter)
+        }
     }
 
     override fun onCreateOptionsMenu(menu: Menu): Boolean {
@@ -62,8 +103,15 @@ open class MainActivity : BaseEuiccAccessActivity(), OpenEuiccContextMarker {
                     position: Int,
                     id: Long
                 ) {
+                    if (position < fragments.size) {
                         supportFragmentManager.beginTransaction()
                             .replace(R.id.fragment_root, fragments[position]).commit()
+                    } else if (position == fragments.size) {
+                        // If we are at the last position, this is the USB device
+                        lifecycleScope.launch(Dispatchers.Main) {
+                            switchToUsbFragmentIfPossible()
+                        }
+                    }
                 }
 
                 override fun onNothingSelected(parent: AdapterView<*>?) {
@@ -106,12 +154,22 @@ open class MainActivity : BaseEuiccAccessActivity(), OpenEuiccContextMarker {
             }
         }
 
+        withContext(Dispatchers.IO) {
+            val res = euiccChannelManager.enumerateUsbEuiccChannel()
+            usbDevice = res.first
+            usbChannel = res.second
+        }
+
         withContext(Dispatchers.Main) {
             knownChannels.sortedBy { it.logicalSlotId }.forEach { channel ->
                 spinnerAdapter.add(getString(R.string.channel_name_format, channel.logicalSlotId))
                 fragments.add(appContainer.uiComponentFactory.createEuiccManagementFragment(channel))
             }
 
+            // If USB readers exist, add them at the very last
+            // The adapter logic depends on this assumption
+            usbDevice?.let { spinnerAdapter.add(it.productName) }
+
             if (fragments.isNotEmpty()) {
                 if (this@MainActivity::spinner.isInitialized) {
                     spinnerItem.isVisible = true
@@ -120,4 +178,27 @@ open class MainActivity : BaseEuiccAccessActivity(), OpenEuiccContextMarker {
             }
         }
     }
+
+    private suspend fun switchToUsbFragmentIfPossible() {
+        if (usbDevice != null && usbChannel == null) {
+            if (!usbManager.hasPermission(usbDevice)) {
+                usbManager.requestPermission(usbDevice, usbPendingIntent)
+                return
+            }  else {
+               val (device, channel) = withContext(Dispatchers.IO) {
+                    euiccChannelManager.enumerateUsbEuiccChannel()
+                }
+
+                if (device != null && channel != null) {
+                    usbDevice = device
+                    usbChannel = channel
+                }
+            }
+        }
+
+        if (usbChannel != null) {
+            supportFragmentManager.beginTransaction().replace(R.id.fragment_root,
+                appContainer.uiComponentFactory.createEuiccManagementFragment(usbChannel!!)).commit()
+        }
+    }
 }

app-common/src/main/java/im/angry/openeuicc/ui/NotificationsActivity.kt

@@ -180,8 +180,9 @@ class NotificationsActivity: BaseEuiccAccessActivity(), OpenEuiccContextMarker {
                         withContext(Dispatchers.IO) {
                             euiccChannel.lpa.handleNotification(notification.inner.seqNumber)
                         }
-                    }
+
                         refresh()
+                    }
                     true
                 }
                 R.id.notification_delete -> {
@@ -189,8 +190,9 @@ class NotificationsActivity: BaseEuiccAccessActivity(), OpenEuiccContextMarker {
                         withContext(Dispatchers.IO) {
                             euiccChannel.lpa.deleteNotification(notification.inner.seqNumber)
                         }
-                    }
+
                         refresh()
+                    }
                     true
                 }
                 else -> false

app/src/main/java/im/angry/openeuicc/util/PrivilegedTelephonyUtils.kt

@@ -74,11 +74,12 @@ fun SubscriptionManager.tryRefreshCachedEuiccInfo(cardId: Int) {
 }
 
 // Every EuiccChannel we use here should be backed by a RealUiccPortInfoCompat
+// except when it is from a USB card reader
 val EuiccChannel.removable
-    get() = (port as RealUiccPortInfoCompat).card.isRemovable
+    get() = (port as? RealUiccPortInfoCompat)?.card?.isRemovable ?: true
 
 val EuiccChannel.cardId
-    get() = (port as RealUiccPortInfoCompat).card.cardId
+    get() = (port as? RealUiccPortInfoCompat)?.card?.cardId ?: -1
 
 val EuiccChannel.isMEP
-    get() = (port as RealUiccPortInfoCompat).card.isMultipleEnabledProfilesSupported
+    get() = (port as? RealUiccPortInfoCompat)?.card?.isMultipleEnabledProfilesSupported ?: false