diff options
Diffstat (limited to 'OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/NfcOperationActivity.java')
| -rw-r--r-- | OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/NfcOperationActivity.java | 492 |
1 files changed, 492 insertions, 0 deletions
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/NfcOperationActivity.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/NfcOperationActivity.java new file mode 100644 index 000000000..c1403d748 --- /dev/null +++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/NfcOperationActivity.java @@ -0,0 +1,492 @@ +/** + * Copyright (c) 2013-2014 Philipp Jakubeit, Signe Rüsch, Dominik Schürmann + * + * Licensed under the Bouncy Castle License (MIT license). See LICENSE file for details. + */ + +package org.sufficientlysecure.keychain.ui; + +import android.annotation.TargetApi; +import android.app.PendingIntent; +import android.content.Intent; +import android.content.IntentFilter; +import android.nfc.NfcAdapter; +import android.nfc.Tag; +import android.nfc.tech.IsoDep; +import android.os.Build; +import android.os.Bundle; +import android.view.WindowManager; +import android.widget.Toast; + +import org.spongycastle.bcpg.HashAlgorithmTags; +import org.spongycastle.util.encoders.Hex; +import org.sufficientlysecure.keychain.Constants; +import org.sufficientlysecure.keychain.R; +import org.sufficientlysecure.keychain.service.input.CryptoInputParcel; +import org.sufficientlysecure.keychain.service.input.NfcOperationsParcel; +import org.sufficientlysecure.keychain.util.Iso7816TLV; +import org.sufficientlysecure.keychain.util.Log; + +import java.io.IOException; +import java.nio.ByteBuffer; + + +/** + * This class provides a communication interface to OpenPGP applications on ISO SmartCard compliant + * NFC devices. + * + * For the full specs, see http://g10code.com/docs/openpgp-card-2.0.pdf + */ +@TargetApi(Build.VERSION_CODES.GINGERBREAD_MR1) +public class NfcOperationActivity extends BaseActivity { + + public static final String EXTRA_PIN = "pin"; + public static final String EXTRA_NFC_OPS = "nfc_operations"; + + public static final String RESULT_DATA = "result_data"; + + private static final int TIMEOUT = 100000; + + private NfcAdapter mNfcAdapter; + private IsoDep mIsoDep; + + private String mPin; + + NfcOperationsParcel mNfcOperations; + + @Override + protected void onCreate(Bundle savedInstanceState) { + super.onCreate(savedInstanceState); + Log.d(Constants.TAG, "NfcOperationActivity.onCreate"); + + getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON); + + Intent intent = getIntent(); + String action = intent.getAction(); + if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(action)) { + throw new AssertionError("should not happen: NfcOperationActivity.onCreate is called instead of onNewIntent!"); + } + + Bundle data = intent.getExtras(); + + mNfcOperations = data.getParcelable(EXTRA_NFC_OPS); + mPin = data.getString(EXTRA_PIN); + + } + + @Override + protected void initLayout() { + setContentView(R.layout.nfc_activity); + } + + /** + * Called when the system is about to start resuming a previous activity, + * disables NFC Foreground Dispatch + */ + public void onPause() { + super.onPause(); + Log.d(Constants.TAG, "NfcOperationActivity.onPause"); + + disableNfcForegroundDispatch(); + } + + /** + * Called when the activity will start interacting with the user, + * enables NFC Foreground Dispatch + */ + public void onResume() { + super.onResume(); + Log.d(Constants.TAG, "NfcOperationActivity.onResume"); + + enableNfcForegroundDispatch(); + } + + /** + * This activity is started as a singleTop activity. + * All new NFC Intents which are delivered to this activity are handled here + */ + public void onNewIntent(Intent intent) { + if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(intent.getAction())) { + try { + handleNdefDiscoveredIntent(intent); + } catch (IOException e) { + Log.e(Constants.TAG, "Connection error!", e); + toast("Connection Error: " + e.getMessage()); + setResult(RESULT_CANCELED); + finish(); + } + } + } + + /** Handle NFC communication and return a result. + * + * This method is called by onNewIntent above upon discovery of an NFC tag. + * It handles initialization and login to the application, subsequently + * calls either nfcCalculateSignature() or nfcDecryptSessionKey(), then + * finishes the activity with an appropiate result. + * + * On general communication, see also + * http://www.cardwerk.com/smartcards/smartcard_standard_ISO7816-4_annex-a.aspx + * + * References to pages are generally related to the OpenPGP Application + * on ISO SmartCard Systems specification. + * + */ + private void handleNdefDiscoveredIntent(Intent intent) throws IOException { + + Tag detectedTag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG); + + // Connect to the detected tag, setting a couple of settings + mIsoDep = IsoDep.get(detectedTag); + mIsoDep.setTimeout(TIMEOUT); // timeout is set to 100 seconds to avoid cancellation during calculation + mIsoDep.connect(); + + // SW1/2 0x9000 is the generic "ok" response, which we expect most of the time. + // See specification, page 51 + String accepted = "9000"; + + // Command APDU (page 51) for SELECT FILE command (page 29) + String opening = + "00" // CLA + + "A4" // INS + + "04" // P1 + + "00" // P2 + + "06" // Lc (number of bytes) + + "D27600012401" // Data (6 bytes) + + "00"; // Le + if ( ! card(opening).equals(accepted)) { // activate connection + toast("Opening Error!"); + setResult(RESULT_CANCELED); + finish(); + return; + } + + // Command APDU for VERIFY command (page 32) + String login = + "00" // CLA + + "20" // INS + + "00" // P1 + + "82" // P2 (PW1) + + String.format("%02x", mPin.length()) // Lc + + Hex.toHexString(mPin.getBytes()); + if ( ! card(login).equals(accepted)) { // login + toast("Wrong PIN!"); + setResult(RESULT_CANCELED); + finish(); + return; + } + + CryptoInputParcel resultData = new CryptoInputParcel(mNfcOperations.mSignatureTime); + + switch (mNfcOperations.mType) { + + case NFC_DECRYPT: + + for (int i = 0; i < mNfcOperations.mInputHash.length; i++) { + byte[] hash = mNfcOperations.mInputHash[i]; + byte[] decryptedSessionKey = nfcDecryptSessionKey(hash); + resultData.addCryptoData(hash, decryptedSessionKey); + } + break; + + case NFC_SIGN: + for (int i = 0; i < mNfcOperations.mInputHash.length; i++) { + byte[] hash = mNfcOperations.mInputHash[i]; + int algo = mNfcOperations.mSignAlgo[i]; + byte[] signedHash = nfcCalculateSignature(hash, algo); + resultData.addCryptoData(hash, signedHash); + } + break; + } + + // give data through for new service call + Intent result = new Intent(); + result.putExtra(RESULT_DATA, resultData); + setResult(RESULT_OK, result); + finish(); + + } + + /** + * Gets the user ID + * + * @return the user id as "name <email>" + * @throws java.io.IOException + */ + public String getUserId() throws IOException { + String info = "00CA006500"; + String data = "00CA005E00"; + return getName(card(info)) + " <" + (new String(Hex.decode(getDataField(card(data))))) + ">"; + } + + /** Return the key id from application specific data stored on tag, or null + * if it doesn't exist. + * + * @param idx Index of the key to return the fingerprint from. + * @return The long key id of the requested key, or null if not found. + */ + public static Long nfcGetKeyId(IsoDep isoDep, int idx) throws IOException { + byte[] fp = nfcGetFingerprint(isoDep, idx); + if (fp == null) { + return null; + } + ByteBuffer buf = ByteBuffer.wrap(fp); + // skip first 12 bytes of the fingerprint + buf.position(12); + // the last eight bytes are the key id (big endian, which is default order in ByteBuffer) + return buf.getLong(); + } + + /** Return fingerprints of all keys from application specific data stored + * on tag, or null if data not available. + * + * @return The fingerprints of all subkeys in a contiguous byte array. + */ + public static byte[] nfcGetFingerprints(IsoDep isoDep) throws IOException { + String data = "00CA006E00"; + byte[] buf = isoDep.transceive(Hex.decode(data)); + + Iso7816TLV tlv = Iso7816TLV.readSingle(buf, true); + Log.d(Constants.TAG, "nfc tlv data:\n" + tlv.prettyPrint()); + + Iso7816TLV fptlv = Iso7816TLV.findRecursive(tlv, 0xc5); + if (fptlv == null) { + return null; + } + + return fptlv.mV; + } + + /** Return the fingerprint from application specific data stored on tag, or + * null if it doesn't exist. + * + * @param idx Index of the key to return the fingerprint from. + * @return The fingerprint of the requested key, or null if not found. + */ + public static byte[] nfcGetFingerprint(IsoDep isoDep, int idx) throws IOException { + byte[] data = nfcGetFingerprints(isoDep); + + // return the master key fingerprint + ByteBuffer fpbuf = ByteBuffer.wrap(data); + byte[] fp = new byte[20]; + fpbuf.position(idx*20); + fpbuf.get(fp, 0, 20); + + return fp; + } + + /** + * Calls to calculate the signature and returns the MPI value + * + * @param hash the hash for signing + * @return a big integer representing the MPI for the given hash + * @throws java.io.IOException + */ + public byte[] nfcCalculateSignature(byte[] hash, int hashAlgo) throws IOException { + + // dsi, including Lc + String dsi; + + Log.i(Constants.TAG, "Hash: " + hashAlgo); + switch (hashAlgo) { + case HashAlgorithmTags.SHA1: + if (hash.length != 20) { + throw new RuntimeException("Bad hash length (" + hash.length + ", expected 10!"); + } + dsi = "23" // Lc + + "3021" // Tag/Length of Sequence, the 0x21 includes all following 33 bytes + + "3009" // Tag/Length of Sequence, the 0x09 are the following header bytes + + "0605" + "2B0E03021A" // OID of SHA1 + + "0500" // TLV coding of ZERO + + "0414" + getHex(hash); // 0x14 are 20 hash bytes + break; + case HashAlgorithmTags.RIPEMD160: + if (hash.length != 20) { + throw new RuntimeException("Bad hash length (" + hash.length + ", expected 20!"); + } + dsi = "233021300906052B2403020105000414" + getHex(hash); + break; + case HashAlgorithmTags.SHA224: + if (hash.length != 28) { + throw new RuntimeException("Bad hash length (" + hash.length + ", expected 28!"); + } + dsi = "2F302D300D06096086480165030402040500041C" + getHex(hash); + break; + case HashAlgorithmTags.SHA256: + if (hash.length != 32) { + throw new RuntimeException("Bad hash length (" + hash.length + ", expected 32!"); + } + dsi = "333031300D060960864801650304020105000420" + getHex(hash); + break; + case HashAlgorithmTags.SHA384: + if (hash.length != 48) { + throw new RuntimeException("Bad hash length (" + hash.length + ", expected 48!"); + } + dsi = "433041300D060960864801650304020205000430" + getHex(hash); + break; + case HashAlgorithmTags.SHA512: + if (hash.length != 64) { + throw new RuntimeException("Bad hash length (" + hash.length + ", expected 64!"); + } + dsi = "533051300D060960864801650304020305000440" + getHex(hash); + break; + default: + throw new RuntimeException("Not supported hash algo!"); + } + + // Command APDU for PERFORM SECURITY OPERATION: COMPUTE DIGITAL SIGNATURE (page 37) + String apdu = + "002A9E9A" // CLA, INS, P1, P2 + + dsi // digital signature input + + "00"; // Le + + String response = card(apdu); + + // split up response into signature and status + String status = response.substring(response.length()-4); + String signature = response.substring(0, response.length() - 4); + + // while we are getting 0x61 status codes, retrieve more data + while (status.substring(0, 2).equals("61")) { + Log.d(Constants.TAG, "requesting more data, status " + status); + // Send GET RESPONSE command + response = card("00C00000" + status.substring(2)); + status = response.substring(response.length()-4); + signature += response.substring(0, response.length()-4); + } + + Log.d(Constants.TAG, "final response:" + status); + + if ( ! status.equals("9000")) { + toast("Bad NFC response code: " + status); + return null; + } + + // Make sure the signature we received is actually the expected number of bytes long! + if (signature.length() != 256 && signature.length() != 512) { + toast("Bad signature length! Expected 128 or 256 bytes, got " + signature.length() / 2); + return null; + } + + return Hex.decode(signature); + } + + /** + * Calls to calculate the signature and returns the MPI value + * + * @param encryptedSessionKey the encoded session key + * @return the decoded session key + * @throws java.io.IOException + */ + public byte[] nfcDecryptSessionKey(byte[] encryptedSessionKey) throws IOException { + String firstApdu = "102a8086fe"; + String secondApdu = "002a808603"; + String le = "00"; + + byte[] one = new byte[254]; + // leave out first byte: + System.arraycopy(encryptedSessionKey, 1, one, 0, one.length); + + byte[] two = new byte[encryptedSessionKey.length - 1 - one.length]; + for (int i = 0; i < two.length; i++) { + two[i] = encryptedSessionKey[i + one.length + 1]; + } + + String first = card(firstApdu + getHex(one)); + String second = card(secondApdu + getHex(two) + le); + + String decryptedSessionKey = getDataField(second); + + Log.d(Constants.TAG, "decryptedSessionKey: " + decryptedSessionKey); + + return Hex.decode(decryptedSessionKey); + } + + /** + * Prints a message to the screen + * + * @param text the text which should be contained within the toast + */ + private void toast(String text) { + Toast.makeText(this, text, Toast.LENGTH_LONG).show(); + } + + /** + * Receive new NFC Intents to this activity only by enabling foreground dispatch. + * This can only be done in onResume! + */ + public void enableNfcForegroundDispatch() { + mNfcAdapter = NfcAdapter.getDefaultAdapter(this); + Intent nfcI = new Intent(this, NfcOperationActivity.class) + .addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP | Intent.FLAG_ACTIVITY_CLEAR_TOP); + PendingIntent nfcPendingIntent = PendingIntent.getActivity(this, 0, nfcI, PendingIntent.FLAG_CANCEL_CURRENT); + IntentFilter[] writeTagFilters = new IntentFilter[]{ + new IntentFilter(NfcAdapter.ACTION_TAG_DISCOVERED) + }; + + // https://code.google.com/p/android/issues/detail?id=62918 + // maybe mNfcAdapter.enableReaderMode(); ? + try { + mNfcAdapter.enableForegroundDispatch(this, nfcPendingIntent, writeTagFilters, null); + } catch (IllegalStateException e) { + Log.i(Constants.TAG, "NfcForegroundDispatch Error!", e); + } + Log.d(Constants.TAG, "NfcForegroundDispatch has been enabled!"); + } + + /** + * Disable foreground dispatch in onPause! + */ + public void disableNfcForegroundDispatch() { + mNfcAdapter.disableForegroundDispatch(this); + Log.d(Constants.TAG, "NfcForegroundDispatch has been disabled!"); + } + + /** + * Gets the name of the user out of the raw card output regarding card holder related data + * + * @param name the raw card holder related data from the card + * @return the name given in this data + */ + public String getName(String name) { + String slength; + int ilength; + name = name.substring(6); + slength = name.substring(0, 2); + ilength = Integer.parseInt(slength, 16) * 2; + name = name.substring(2, ilength + 2); + name = (new String(Hex.decode(name))).replace('<', ' '); + return (name); + } + + /** + * Reduces the raw data from the card by four characters + * + * @param output the raw data from the card + * @return the data field of that data + */ + private String getDataField(String output) { + return output.substring(0, output.length() - 4); + } + + /** + * Communicates with the OpenPgpCard via the APDU + * + * @param hex the hexadecimal APDU + * @return The answer from the card + * @throws java.io.IOException throws an exception if something goes wrong + */ + public String card(String hex) throws IOException { + return getHex(mIsoDep.transceive(Hex.decode(hex))); + } + + /** + * Converts a byte array into an hex string + * + * @param raw the byte array representation + * @return the hexadecimal string representation + */ + public static String getHex(byte[] raw) { + return new String(Hex.encode(raw)); + } +} |