Merge "Keystore 2.0: Add keystore engine grant string convenience functions."

import android.os.ServiceManager;

import android.os.ServiceSpecificException;

import android.security.keymaster.KeymasterDefs;

import android.system.keystore2.Domain;

import android.system.keystore2.IKeystoreService;

import android.system.keystore2.KeyDescriptor;

import android.system.keystore2.KeyEntryResponse;

        return handleRemoteExceptionWithRetry((service) -> service.listEntries(domain, namespace));

    }

    /**

     * Grant string prefix as used by the keystore boringssl engine. Must be kept in sync

     * with system/security/keystore-engine. Note: The prefix here includes the 0x which

     * std::stringstream used in keystore-engine needs to identify the number as hex represented.

     * Here we include it in the prefix, because Long#parseUnsignedLong does not understand it

     * and gets the radix as explicit argument.

     * @hide

     */

    private static final String KEYSTORE_ENGINE_GRANT_ALIAS_PREFIX =

            "ks2_keystore-engine_grant_id:0x";

    /**

     * This function turns a grant identifier into a specific string that is understood by the

     * keystore-engine in system/security/keystore-engine. Is only used by VPN and WI-FI components

     * to allow certain system components like racoon or vendor components like WPA supplicant

     * to use keystore keys with boring ssl.

     *

     * @param grantId the grant id as returned by {@link #grant} in the {@code nspace} filed of

     *                the resulting {@code KeyDescriptor}.

     * @return The grant descriptor string.

     * @hide

     */

    public static String makeKeystoreEngineGrantString(long grantId) {

        return String.format("%s%016X", KEYSTORE_ENGINE_GRANT_ALIAS_PREFIX, grantId);

    }

    /**

     * Convenience function to turn a keystore engine grant string as returned by

     * {@link #makeKeystoreEngineGrantString(long)} back into a grant KeyDescriptor.

     *

     * @param grantString As string returned by {@link #makeKeystoreEngineGrantString(long)}

     * @return The grant key descriptor.

     * @hide

     */

    public static KeyDescriptor keystoreEngineGrantString2KeyDescriptor(String grantString) {

        KeyDescriptor key = new KeyDescriptor();

        key.domain = Domain.GRANT;

        key.nspace = Long.parseUnsignedLong(

                grantString.substring(KEYSTORE_ENGINE_GRANT_ALIAS_PREFIX.length()), 16);

        key.alias = null;

        key.blob = null;

        return key;

    }

    /**

     * Create a grant that allows the grantee identified by {@code granteeUid} to use

     * the key specified by {@code descriptor} withint the restrictions given by