Merge "Handle issuer and key type restrictions."

import java.io.ByteArrayInputStream;

import java.io.Closeable;

import java.io.Serializable;

import java.security.KeyPair;

import java.security.Principal;

import java.security.PrivateKey;

import java.util.concurrent.BlockingQueue;

import java.util.concurrent.LinkedBlockingQueue;

import javax.security.auth.x500.X500Principal;

import com.android.org.conscrypt.TrustedCertificateStore;

/**

     */

    public static final String EXTRA_SENDER = "sender";

    /**

     * Extra for use with {@link #ACTION_CHOOSER}

     * @hide Also used by KeyChainActivity implementation

     */

    public static final String EXTRA_KEY_TYPES = "key_types";

    /**

     * Extra for use with {@link #ACTION_CHOOSER}

     * @hide Also used by KeyChainActivity implementation

     */

    public static final String EXTRA_ISSUERS = "issuers";

    /**

     * Action to bring up the CertInstaller.

     */

     * onChoosePrivateKeyAlias}.

     *

     * <p>{@code keyTypes} and {@code issuers} may be used to

     * highlight suggested choices to the user, although to cope with

     * sometimes erroneous values provided by servers, the user may be

     * able to override these suggestions.

     * narrow down suggested choices to the user. If either {@code keyTypes}

     * or {@code issuers} is specified and non-empty, and there are no

     * matching certificates in the KeyChain, then the certificate

     * selection prompt would be suppressed entirely.

     *

     * <p>{@code host} and {@code port} may be used to give the user

     * more context about the server requesting the credentials.

     * @param response Callback to invoke when the request completes;

     *     must not be null.

     * @param keyTypes The acceptable types of asymmetric keys such as

     *     "RSA" or "DSA", or null.

     *     "RSA", "EC" or null.

     * @param issuers The acceptable certificate issuers for the

     *     certificate matching the private key, or null.

     * @param host The host name of the server requesting the

     * onChoosePrivateKeyAlias}.

     *

     * <p>{@code keyTypes} and {@code issuers} may be used to

     * highlight suggested choices to the user, although to cope with

     * sometimes erroneous values provided by servers, the user may be

     * able to override these suggestions.

     * narrow down suggested choices to the user. If either {@code keyTypes}

     * or {@code issuers} is specified and non-empty, and there are no

     * matching certificates in the KeyChain, then the certificate

     * selection prompt would be suppressed entirely.

     *

     * <p>{@code uri} may be used to give the user more context about

     * the server requesting the credentials.

     * @param response Callback to invoke when the request completes;

     *     must not be null.

     * @param keyTypes The acceptable types of asymmetric keys such as

     *     "EC" or "RSA", or null.

     *     "RSA", "EC" or null.

     * @param issuers The acceptable certificate issuers for the

     *     certificate matching the private key, or null.

     * @param uri The full URI the server is requesting the certificate

     *     for, or null if unavailable.

     * @param alias The alias to preselect if available, or null if

     *     unavailable.

     * @throws IllegalArgumentException if the specified issuers are not

     *     of type {@code X500Principal}.

     */

    public static void choosePrivateKeyAlias(@NonNull Activity activity,

            @NonNull KeyChainAliasCallback response,

            @Nullable Principal[] issuers,

            @Nullable Uri uri, @Nullable String alias) {

        /*

         * TODO currently keyTypes, issuers are unused. They are meant

         * to follow the semantics and purpose of X509KeyManager

         * method arguments.

         *

         * keyTypes would allow the list to be filtered and typically

         * will be set correctly by the server. In practice today,

         * most all users will want only RSA or EC, and usually

         * only a small number of certs will be available.

         *

         * issuers is typically not useful. Some servers historically

         * will send the entire list of public CAs known to the

         * server. Others will send none. If this is used, if there

         * are no matches after applying the constraint, it should be

         * ignored.

         * Specifying keyTypes excludes certificates with different key types

         * from the list of certificates presented to the user.

         * In practice today, most servers would require RSA or EC

         * certificates.

         *

         * Specifying issuers narrows down the list by filtering out

         * certificates with issuers which are not matching the provided ones.

         * This has been reported to Chrome several times (crbug.com/731769).

         * There's no concrete description on what to do when the client has no

         * certificates that match the provided issuers.

         * To be conservative, Android will not present the user with any

         * certificates to choose from.

         * If the list of issuers is empty then the client may send any

         * certificate, see:

         * https://tools.ietf.org/html/rfc5246#section-7.4.4

         */

        if (activity == null) {

            throw new NullPointerException("activity == null");

        intent.putExtra(EXTRA_RESPONSE, new AliasResponse(response));

        intent.putExtra(EXTRA_URI, uri);

        intent.putExtra(EXTRA_ALIAS, alias);

        intent.putExtra(EXTRA_KEY_TYPES, keyTypes);

        ArrayList<byte[]> issuersList = new ArrayList();

        if (issuers != null) {

            for (Principal issuer: issuers) {

                // In a TLS client context (like Chrome), issuers would only

                // be specified as X500Principals. No other use cases for

                // specifying principals have been brought up. Under these

                // circumstances, only allow issuers specified as

                // X500Principals.

                if (!(issuer instanceof X500Principal)) {

                    throw new IllegalArgumentException(String.format(

                            "Issuer %s is of type %s, not X500Principal",

                            issuer.toString(), issuer.getClass()));

                }

                // Pass the DER-encoded issuer as that's the most accurate

                // representation and what is sent over the wire.

                issuersList.add(((X500Principal) issuer).getEncoded());

            }

        }

        intent.putExtra(EXTRA_ISSUERS, (Serializable) issuersList);

        // the PendingIntent is used to get calling package name

        intent.putExtra(EXTRA_SENDER, PendingIntent.getActivity(activity, 0, new Intent(), 0));

        activity.startActivity(intent);