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/**
* 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.content.Intent;
import android.os.Bundle;
import android.view.WindowManager;
import org.sufficientlysecure.keychain.Constants;
import org.sufficientlysecure.keychain.R;
import org.sufficientlysecure.keychain.pgp.CanonicalizedSecretKey;
import org.sufficientlysecure.keychain.pgp.CanonicalizedSecretKeyRing;
import org.sufficientlysecure.keychain.provider.KeychainContract;
import org.sufficientlysecure.keychain.provider.ProviderHelper;
import org.sufficientlysecure.keychain.remote.CryptoInputParcelCacheService;
import org.sufficientlysecure.keychain.service.PassphraseCacheService;
import org.sufficientlysecure.keychain.service.input.CryptoInputParcel;
import org.sufficientlysecure.keychain.service.input.RequiredInputParcel;
import org.sufficientlysecure.keychain.ui.base.BaseNfcActivity;
import org.sufficientlysecure.keychain.util.Log;
import org.sufficientlysecure.keychain.util.Passphrase;
import org.sufficientlysecure.keychain.util.Preferences;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Arrays;
/**
* This class provides a communication interface to OpenPGP applications on ISO SmartCard compliant
* NFC devices.
* <p/>
* For the full specs, see http://g10code.com/docs/openpgp-card-2.0.pdf
*/
public class NfcOperationActivity extends BaseNfcActivity {
public static final String EXTRA_REQUIRED_INPUT = "required_input";
// passthrough for OpenPgpService
public static final String EXTRA_SERVICE_INTENT = "data";
public static final String RESULT_DATA = "result_data";
private RequiredInputParcel mRequiredInput;
private Intent mServiceIntent;
private static final byte[] BLANK_FINGERPRINT = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
@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();
Bundle data = intent.getExtras();
mRequiredInput = data.getParcelable(EXTRA_REQUIRED_INPUT);
mServiceIntent = data.getParcelable(EXTRA_SERVICE_INTENT);
// obtain passphrase for this subkey
if (mRequiredInput.mType != RequiredInputParcel.RequiredInputType.NFC_MOVE_KEY_TO_CARD) {
obtainYubiKeyPin(mRequiredInput);
}
}
@Override
protected void initLayout() {
setContentView(R.layout.nfc_activity);
}
@Override
protected void onNfcPerform() throws IOException {
CryptoInputParcel inputParcel = new CryptoInputParcel(mRequiredInput.mSignatureTime);
switch (mRequiredInput.mType) {
case NFC_DECRYPT: {
for (int i = 0; i < mRequiredInput.mInputHashes.length; i++) {
byte[] hash = mRequiredInput.mInputHashes[i];
byte[] decryptedSessionKey = nfcDecryptSessionKey(hash);
inputParcel.addCryptoData(hash, decryptedSessionKey);
}
break;
}
case NFC_SIGN: {
for (int i = 0; i < mRequiredInput.mInputHashes.length; i++) {
byte[] hash = mRequiredInput.mInputHashes[i];
int algo = mRequiredInput.mSignAlgos[i];
byte[] signedHash = nfcCalculateSignature(hash, algo);
inputParcel.addCryptoData(hash, signedHash);
}
break;
}
case NFC_MOVE_KEY_TO_CARD: {
ProviderHelper providerHelper = new ProviderHelper(this);
CanonicalizedSecretKeyRing secretKeyRing;
try {
secretKeyRing = providerHelper.getCanonicalizedSecretKeyRing(
KeychainContract.KeyRings.buildUnifiedKeyRingsFindBySubkeyUri(mRequiredInput.getMasterKeyId())
);
} catch (ProviderHelper.NotFoundException e) {
throw new IOException("Couldn't find subkey for key to card operation.");
}
for (int i = 0; i < mRequiredInput.mInputHashes.length; i++) {
byte[] subkeyBytes = mRequiredInput.mInputHashes[i];
ByteBuffer buf = ByteBuffer.wrap(subkeyBytes);
long subkeyId = buf.getLong();
CanonicalizedSecretKey key = secretKeyRing.getSecretKey(subkeyId);
long keyGenerationTimestampMillis = key.getCreationTime().getTime();
long keyGenerationTimestamp = keyGenerationTimestampMillis / 1000;
byte[] timestampBytes = ByteBuffer.allocate(4).putInt((int) keyGenerationTimestamp).array();
byte[] cardSerialNumber = Arrays.copyOf(nfcGetAid(), 16);
Passphrase passphrase;
try {
passphrase = PassphraseCacheService.getCachedPassphrase(this,
mRequiredInput.getMasterKeyId(), mRequiredInput.getSubKeyId());
} catch (PassphraseCacheService.KeyNotFoundException e) {
throw new IOException("Unable to get cached passphrase!");
}
if (key.canSign() || key.canCertify()) {
if (shouldPutKey(key.getFingerprint(), 0)) {
nfcPutKey(0xB6, key, passphrase);
nfcPutData(0xCE, timestampBytes);
nfcPutData(0xC7, key.getFingerprint());
} else {
throw new IOException("Key slot occupied; card must be reset to put new signature key.");
}
} else if (key.canEncrypt()) {
if (shouldPutKey(key.getFingerprint(), 1)) {
nfcPutKey(0xB8, key, passphrase);
nfcPutData(0xCF, timestampBytes);
nfcPutData(0xC8, key.getFingerprint());
} else {
throw new IOException("Key slot occupied; card must be reset to put new decryption key.");
}
} else if (key.canAuthenticate()) {
if (shouldPutKey(key.getFingerprint(), 2)) {
nfcPutKey(0xA4, key, passphrase);
nfcPutData(0xD0, timestampBytes);
nfcPutData(0xC9, key.getFingerprint());
} else {
throw new IOException("Key slot occupied; card must be reset to put new authentication key.");
}
} else {
throw new IOException("Inappropriate key flags for smart card key.");
}
inputParcel.addCryptoData(subkeyBytes, cardSerialNumber);
}
}
}
if (mServiceIntent != null) {
CryptoInputParcelCacheService.addCryptoInputParcel(this, mServiceIntent, inputParcel);
setResult(RESULT_OK, mServiceIntent);
} else {
Intent result = new Intent();
result.putExtra(NfcOperationActivity.RESULT_DATA, inputParcel);
setResult(RESULT_OK, result);
}
finish();
}
private boolean shouldPutKey(byte[] fingerprint, int idx) throws IOException {
byte[] cardFingerprint = nfcGetFingerprint(idx);
// Slot is empty, or contains this key already. PUT KEY operation is safe
if (Arrays.equals(cardFingerprint, BLANK_FINGERPRINT) ||
Arrays.equals(cardFingerprint, fingerprint)) {
return true;
}
// Slot already contains a different key; don't overwrite it.
return false;
}
@Override
public void handlePinError() {
// avoid a loop
Preferences prefs = Preferences.getPreferences(this);
if (prefs.useDefaultYubiKeyPin()) {
toast(getString(R.string.error_pin_nodefault));
setResult(RESULT_CANCELED);
finish();
return;
}
// clear (invalid) passphrase
PassphraseCacheService.clearCachedPassphrase(
this, mRequiredInput.getMasterKeyId(), mRequiredInput.getSubKeyId());
obtainYubiKeyPin(mRequiredInput);
}
}
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