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Diffstat (limited to 'core/java/android/security/ConfirmationDialog.java')
| -rw-r--r-- | core/java/android/security/ConfirmationDialog.java | 332 |
1 files changed, 0 insertions, 332 deletions
diff --git a/core/java/android/security/ConfirmationDialog.java b/core/java/android/security/ConfirmationDialog.java deleted file mode 100644 index 1697106c3782..000000000000 --- a/core/java/android/security/ConfirmationDialog.java +++ /dev/null @@ -1,332 +0,0 @@ -/* - * Copyright 2018 The Android Open Source Project - * - * Licensed under the Apache License, Version 2.0 (the "License"); - * you may not use this file except in compliance with the License. - * You may obtain a copy of the License at - * - * http://www.apache.org/licenses/LICENSE-2.0 - * - * Unless required by applicable law or agreed to in writing, software - * distributed under the License is distributed on an "AS IS" BASIS, - * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - * See the License for the specific language governing permissions and - * limitations under the License. - */ - -package android.security; - -import android.annotation.NonNull; -import android.content.ContentResolver; -import android.content.Context; -import android.provider.Settings; -import android.provider.Settings.SettingNotFoundException; -import android.text.TextUtils; -import android.util.Log; - -import java.util.Locale; -import java.util.concurrent.Executor; - -/** - * Class used for displaying confirmation prompts. - * - * <p>Confirmation prompts are prompts shown to the user to confirm a given text and are - * implemented in a way that a positive response indicates with high confidence that the user has - * seen the given text, even if the Android framework (including the kernel) was - * compromised. Implementing confirmation prompts with these guarantees requires dedicated - * hardware-support and may not always be available. - * - * <p>Confirmation prompts are typically used with an external entitity - the <i>Relying Party</i> - - * in the following way. The setup steps are as follows: - * <ul> - * <li> Before first use, the application generates a key-pair with the - * {@link android.security.keystore.KeyGenParameterSpec.Builder#setUserConfirmationRequired - * CONFIRMATION tag} set. Device attestation, - * e.g. {@link java.security.KeyStore#getCertificateChain getCertificateChain()}, is used to - * generate a certificate chain that includes the public key (<code>Kpub</code> in the following) - * of the newly generated key. - * <li> The application sends <code>Kpub</code> and the certificate chain resulting from device - * attestation to the <i>Relying Party</i>. - * <li> The <i>Relying Party</i> validates the certificate chain which involves checking the root - * certificate is what is expected (e.g. a certificate from Google), each certificate signs the - * next one in the chain, ending with <code>Kpub</code>, and that the attestation certificate - * asserts that <code>Kpub</code> has the - * {@link android.security.keystore.KeyGenParameterSpec.Builder#setUserConfirmationRequired - * CONFIRMATION tag} set. - * Additionally the relying party stores <code>Kpub</code> and associates it with the device - * it was received from. - * </ul> - * - * <p>The <i>Relying Party</i> is typically an external device (for example connected via - * Bluetooth) or application server. - * - * <p>Before executing a transaction which requires a high assurance of user content, the - * application does the following: - * <ul> - * <li> The application gets a cryptographic nonce from the <i>Relying Party</i> and passes this as - * the <code>extraData</code> (via the Builder helper class) to the - * {@link #presentPrompt presentPrompt()} method. The <i>Relying Party</i> stores the nonce locally - * since it'll use it in a later step. - * <li> If the user approves the prompt a <i>Confirmation Response</i> is returned in the - * {@link ConfirmationCallback#onConfirmedByUser onConfirmedByUser(byte[])} callback as the - * <code>dataThatWasConfirmed</code> parameter. This blob contains the text that was shown to the - * user, the <code>extraData</code> parameter, and possibly other data. - * <li> The application signs the <i>Confirmation Response</i> with the previously created key and - * sends the blob and the signature to the <i>Relying Party</i>. - * <li> The <i>Relying Party</i> checks that the signature was made with <code>Kpub</code> and then - * extracts <code>promptText</code> matches what is expected and <code>extraData</code> matches the - * previously created nonce. If all checks passes, the transaction is executed. - * </ul> - * - * <p>A common way of implementing the "<code>promptText</code> is what is expected" check in the - * last bullet, is to have the <i>Relying Party</i> generate <code>promptText</code> and store it - * along the nonce in the <code>extraData</code> blob. - */ -public class ConfirmationDialog { - private static final String TAG = "ConfirmationDialog"; - - private CharSequence mPromptText; - private byte[] mExtraData; - private ConfirmationCallback mCallback; - private Executor mExecutor; - private Context mContext; - - private final KeyStore mKeyStore = KeyStore.getInstance(); - - private void doCallback(int responseCode, byte[] dataThatWasConfirmed, - ConfirmationCallback callback) { - switch (responseCode) { - case KeyStore.CONFIRMATIONUI_OK: - callback.onConfirmedByUser(dataThatWasConfirmed); - break; - - case KeyStore.CONFIRMATIONUI_CANCELED: - callback.onDismissedByUser(); - break; - - case KeyStore.CONFIRMATIONUI_ABORTED: - callback.onDismissedByApplication(); - break; - - case KeyStore.CONFIRMATIONUI_SYSTEM_ERROR: - callback.onError(new Exception("System error returned by ConfirmationUI.")); - break; - - default: - callback.onError(new Exception("Unexpected responseCode=" + responseCode - + " from onConfirmtionPromptCompleted() callback.")); - break; - } - } - - private final android.os.IBinder mCallbackBinder = - new android.security.IConfirmationPromptCallback.Stub() { - @Override - public void onConfirmationPromptCompleted( - int responseCode, final byte[] dataThatWasConfirmed) - throws android.os.RemoteException { - if (mCallback != null) { - ConfirmationCallback callback = mCallback; - Executor executor = mExecutor; - mCallback = null; - mExecutor = null; - if (executor == null) { - doCallback(responseCode, dataThatWasConfirmed, callback); - } else { - executor.execute(new Runnable() { - @Override - public void run() { - doCallback(responseCode, dataThatWasConfirmed, callback); - } - }); - } - } - } - }; - - /** - * A builder that collects arguments, to be shown on the system-provided confirmation dialog. - */ - public static class Builder { - - private CharSequence mPromptText; - private byte[] mExtraData; - - /** - * Creates a builder for the confirmation dialog. - */ - public Builder() { - } - - /** - * Sets the prompt text for the dialog. - * - * @param promptText the text to present in the prompt. - * @return the builder. - */ - public Builder setPromptText(CharSequence promptText) { - mPromptText = promptText; - return this; - } - - /** - * Sets the extra data for the dialog. - * - * @param extraData data to include in the response data. - * @return the builder. - */ - public Builder setExtraData(byte[] extraData) { - mExtraData = extraData; - return this; - } - - /** - * Creates a {@link ConfirmationDialog} with the arguments supplied to this builder. - * - * @param context the application context - * @return a {@link ConfirmationDialog} - * @throws IllegalArgumentException if any of the required fields are not set. - */ - public ConfirmationDialog build(Context context) { - if (TextUtils.isEmpty(mPromptText)) { - throw new IllegalArgumentException("prompt text must be set and non-empty"); - } - if (mExtraData == null) { - throw new IllegalArgumentException("extraData must be set"); - } - return new ConfirmationDialog(context, mPromptText, mExtraData); - } - } - - private ConfirmationDialog(Context context, CharSequence promptText, byte[] extraData) { - mContext = context; - mPromptText = promptText; - mExtraData = extraData; - } - - private static final int UI_OPTION_ACCESSIBILITY_INVERTED_FLAG = 1 << 0; - private static final int UI_OPTION_ACCESSIBILITY_MAGNIFIED_FLAG = 1 << 1; - - private int getUiOptionsAsFlags() { - int uiOptionsAsFlags = 0; - try { - ContentResolver contentResolver = mContext.getContentResolver(); - int inversionEnabled = Settings.Secure.getInt(contentResolver, - Settings.Secure.ACCESSIBILITY_DISPLAY_INVERSION_ENABLED); - if (inversionEnabled == 1) { - uiOptionsAsFlags |= UI_OPTION_ACCESSIBILITY_INVERTED_FLAG; - } - float fontScale = Settings.System.getFloat(contentResolver, - Settings.System.FONT_SCALE); - if (fontScale > 1.0) { - uiOptionsAsFlags |= UI_OPTION_ACCESSIBILITY_MAGNIFIED_FLAG; - } - } catch (SettingNotFoundException e) { - Log.w(TAG, "Unexpected SettingNotFoundException"); - } - return uiOptionsAsFlags; - } - - private boolean isAccessibilityServiceRunning() { - boolean serviceRunning = false; - try { - ContentResolver contentResolver = mContext.getContentResolver(); - int a11yEnabled = Settings.Secure.getInt(contentResolver, - Settings.Secure.ACCESSIBILITY_ENABLED); - if (a11yEnabled == 1) { - serviceRunning = true; - } - } catch (SettingNotFoundException e) { - Log.w(TAG, "Unexpected SettingNotFoundException"); - e.printStackTrace(); - } - return serviceRunning; - } - - /** - * Requests a confirmation prompt to be presented to the user. - * - * When the prompt is no longer being presented, one of the methods in - * {@link ConfirmationCallback} is called on the supplied callback object. - * - * Confirmation dialogs may not be available when accessibility services are running so this - * may fail with a {@link ConfirmationNotAvailableException} exception even if - * {@link #isSupported} returns {@code true}. - * - * @param executor the executor identifying the thread that will receive the callback. - * @param callback the callback to use when the dialog is done showing. - * @throws IllegalArgumentException if the prompt text is too long or malfomed. - * @throws ConfirmationAlreadyPresentingException if another prompt is being presented. - * @throws ConfirmationNotAvailableException if confirmation prompts are not supported. - */ - public void presentPrompt(@NonNull Executor executor, @NonNull ConfirmationCallback callback) - throws ConfirmationAlreadyPresentingException, - ConfirmationNotAvailableException { - if (mCallback != null) { - throw new ConfirmationAlreadyPresentingException(); - } - if (isAccessibilityServiceRunning()) { - throw new ConfirmationNotAvailableException(); - } - mCallback = callback; - mExecutor = executor; - - int uiOptionsAsFlags = getUiOptionsAsFlags(); - String locale = Locale.getDefault().toLanguageTag(); - int responseCode = mKeyStore.presentConfirmationPrompt( - mCallbackBinder, mPromptText.toString(), mExtraData, locale, uiOptionsAsFlags); - switch (responseCode) { - case KeyStore.CONFIRMATIONUI_OK: - return; - - case KeyStore.CONFIRMATIONUI_OPERATION_PENDING: - throw new ConfirmationAlreadyPresentingException(); - - case KeyStore.CONFIRMATIONUI_UNIMPLEMENTED: - throw new ConfirmationNotAvailableException(); - - case KeyStore.CONFIRMATIONUI_UIERROR: - throw new IllegalArgumentException(); - - default: - // Unexpected error code. - Log.w(TAG, - "Unexpected responseCode=" + responseCode - + " from presentConfirmationPrompt() call."); - throw new IllegalArgumentException(); - } - } - - /** - * Cancels a prompt currently being displayed. - * - * On success, the - * {@link ConfirmationCallback#onDismissedByApplication onDismissedByApplication()} method on - * the supplied callback object will be called asynchronously. - * - * @throws IllegalStateException if no prompt is currently being presented. - */ - public void cancelPrompt() { - int responseCode = mKeyStore.cancelConfirmationPrompt(mCallbackBinder); - if (responseCode == KeyStore.CONFIRMATIONUI_OK) { - return; - } else if (responseCode == KeyStore.CONFIRMATIONUI_OPERATION_PENDING) { - throw new IllegalStateException(); - } else { - // Unexpected error code. - Log.w(TAG, - "Unexpected responseCode=" + responseCode - + " from cancelConfirmationPrompt() call."); - throw new IllegalStateException(); - } - } - - /** - * Checks if the device supports confirmation prompts. - * - * @return true if confirmation prompts are supported by the device. - */ - public static boolean isSupported() { - return KeyStore.getInstance().isConfirmationPromptSupported(); - } -} |