Show installed user keys in Security Settings

This makes removing a particular keyset possible without deleting the
whole keystore along with it.

Bug: 22541933
Change-Id: I248803cb27efdd1695438dfc82951887dc579f99

src/com/android/settings/UserCredentialsSettings.java

@@ -0,0 +1,197 @@
+/*
+ * Copyright (C) 2015 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 com.android.settings;
+
+import android.app.AlertDialog;
+import android.app.Dialog;
+import android.app.Fragment;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.os.AsyncTask;
+import android.os.Bundle;
+import android.security.Credentials;
+import android.security.KeyStore;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Adapter;
+import android.widget.AdapterView;
+import android.widget.AdapterView.OnItemClickListener;
+import android.widget.ArrayAdapter;
+import android.widget.ListAdapter;
+import android.widget.Button;
+import android.widget.ListView;
+import android.widget.TextView;
+
+import java.util.EnumSet;
+import java.util.List;
+import java.util.Set;
+import java.util.SortedMap;
+import java.util.TreeMap;
+
+import static android.view.View.VISIBLE;
+import static android.view.View.GONE;
+
+public class UserCredentialsSettings extends InstrumentedFragment implements OnItemClickListener {
+    private static final String TAG = "UserCredentialsSettings";
+
+    private View mRootView;
+    private ListView mListView;
+
+    @Override
+    protected int getMetricsCategory() {
+        // TODO (rgl): Declare a metrics category for user credentials.
+        return UNDECLARED;
+    }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+        new AliasLoader().execute();
+    }
+
+    @Override
+    public View onCreateView(
+            LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState) {
+        mRootView = inflater.inflate(R.layout.user_credentials, parent, false);
+
+        // Set up an OnItemClickListener for the credential list.
+        mListView = (ListView) mRootView.findViewById(R.id.credential_list);
+        mListView.setOnItemClickListener(this);
+
+        return mRootView;
+    }
+
+    @Override
+    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
+        final Credential item = (Credential) parent.getItemAtPosition(position);
+
+        View root = getActivity().getLayoutInflater()
+                .inflate(R.layout.user_credential_dialog, null);
+        ViewGroup infoContainer = (ViewGroup) root.findViewById(R.id.credential_container);
+        infoContainer.addView(parent.getAdapter().getView(position, null, null));
+
+        new AlertDialog.Builder(getActivity())
+                .setView(root)
+                .setTitle(R.string.user_credential_title)
+                .setPositiveButton(R.string.done, null)
+                .setNegativeButton(R.string.trusted_credentials_remove_label,
+                        new DialogInterface.OnClickListener() {
+                            @Override public void onClick(DialogInterface dialog, int id) {
+                                final KeyStore ks = KeyStore.getInstance();
+                                Credentials.deleteAllTypesForAlias(ks, item.alias);
+                                new AliasLoader().execute();
+                                dialog.dismiss();
+                            }
+                        })
+                .show();
+    }
+
+    /**
+     * Opens a background connection to KeyStore to list user credentials.
+     * The credentials are stored in a {@link CredentialAdapter} attached to the main
+     * {@link ListView} in the fragment.
+     */
+    private class AliasLoader extends AsyncTask<Void, Void, ListAdapter> {
+        @Override
+        protected ListAdapter doInBackground(Void... params) {
+            // Create a list of names for credential sets, ordered by name.
+            SortedMap<String, Credential> credentials = new TreeMap<>();
+            KeyStore keyStore = KeyStore.getInstance();
+            for (final Credential.Type type : Credential.Type.values()) {
+                for (final String alias : keyStore.list(type.prefix)) {
+                    Credential c = credentials.get(alias);
+                    if (c == null) {
+                        credentials.put(alias, (c = new Credential(alias)));
+                    }
+                    c.storedTypes.add(type);
+                }
+            }
+
+            // Flatten to array so that the list can be presented via ArrayAdapter.
+            Credential[] results = credentials.values().toArray(new Credential[0]);
+            return new CredentialAdapter(getActivity(), R.layout.user_credential, results);
+        }
+
+        @Override
+        protected void onPostExecute(ListAdapter credentials) {
+            mListView.setAdapter(credentials);
+        }
+    }
+
+    /**
+     * Helper class to display {@link Credential}s in a list.
+     */
+    private static class CredentialAdapter extends ArrayAdapter<Credential> {
+        public CredentialAdapter(Context context, int resource,  Credential[] objects) {
+            super(context, resource, objects);
+        }
+
+        @Override
+        public View getView(int position, View view, ViewGroup parent) {
+            if (view == null) {
+                view = LayoutInflater.from(getContext())
+                        .inflate(R.layout.user_credential, parent, false);
+            }
+            Credential item = getItem(position);
+            ((TextView) view.findViewById(R.id.alias)).setText(item.alias);
+            view.findViewById(R.id.contents_userkey).setVisibility(
+                    item.storedTypes.contains(Credential.Type.USER_PRIVATE_KEY) ? VISIBLE : GONE);
+            view.findViewById(R.id.contents_usercrt).setVisibility(
+                    item.storedTypes.contains(Credential.Type.USER_CERTIFICATE) ? VISIBLE : GONE);
+            view.findViewById(R.id.contents_cacrt).setVisibility(
+                    item.storedTypes.contains(Credential.Type.CA_CERTIFICATE) ? VISIBLE : GONE);
+            return view;
+        }
+    }
+
+    private static class Credential {
+        private static enum Type {
+            CA_CERTIFICATE (Credentials.CA_CERTIFICATE),
+            USER_CERTIFICATE (Credentials.USER_CERTIFICATE),
+            USER_PRIVATE_KEY (Credentials.USER_PRIVATE_KEY),
+            USER_SECRET_KEY (Credentials.USER_SECRET_KEY);
+
+            final String prefix;
+
+            Type(String prefix) {
+                this.prefix = prefix;
+            }
+        }
+
+        /**
+         * Main part of the credential's alias. To fetch an item from KeyStore, prepend one of the
+         * prefixes from {@link CredentialItem.storedTypes}.
+         */
+        final String alias;
+
+        /**
+         * Should contain some non-empty subset of:
+         * <ul>
+         *   <li>{@link Credentials.CA_CERTIFICATE}</li>
+         *   <li>{@link Credentials.USER_CERTIFICATE}</li>
+         *   <li>{@link Credentials.USER_PRIVATE_KEY}</li>
+         *   <li>{@link Credentials.USER_SECRET_KEY}</li>
+         * </ul>
+         */
+        final Set<Type> storedTypes = EnumSet.noneOf(Type.class);
+
+        Credential(final String alias) {
+            this.alias = alias;
+        }
+    }
+}