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Commit 7f414d94 authored by Bo Zhu's avatar Bo Zhu
Browse files

Check the public-key signature of the whole certificate file before 

accepting the certificates

This change requires an additional param to the initRecoveryService()
API to take in the public-key signature.

Bug: 73904566
Test: adb shell am instrument -w -e package \
com.android.server.locksettings.recoverablekeystore \
com.android.frameworks.servicestests/android.support.test.runner.AndroidJUnitRunner

Change-Id: I2aeead1fda51b6cd8df71ed3b5066342ebc8d5ea
parent b1d5004c

api/system-current.txt

+2 −1
Original line number Diff line number Diff line
@@ -4310,7 +4310,8 @@ package android.security.keystore.recovery { 
    method public int[] getRecoverySecretTypes() throws android.security.keystore.recovery.InternalRecoveryServiceException;

    method public deprecated int getRecoveryStatus(java.lang.String, java.lang.String) throws android.security.keystore.recovery.InternalRecoveryServiceException;

    method public int getRecoveryStatus(java.lang.String) throws android.security.keystore.recovery.InternalRecoveryServiceException;

    method public void initRecoveryService(java.lang.String, byte[]) throws java.security.cert.CertificateException, android.security.keystore.recovery.InternalRecoveryServiceException;

    method public deprecated void initRecoveryService(java.lang.String, byte[]) throws java.security.cert.CertificateException, android.security.keystore.recovery.InternalRecoveryServiceException;

    method public void initRecoveryService(java.lang.String, byte[], byte[]) throws java.security.cert.CertificateException, android.security.keystore.recovery.InternalRecoveryServiceException;

    method public void recoverySecretAvailable(android.security.keystore.recovery.KeyChainProtectionParams) throws android.security.keystore.recovery.InternalRecoveryServiceException;

    method public void removeKey(java.lang.String) throws android.security.keystore.recovery.InternalRecoveryServiceException;

    method public void setRecoverySecretTypes(int[]) throws android.security.keystore.recovery.InternalRecoveryServiceException;

core/java/android/security/keystore/recovery/RecoveryController.java

+64 −17
Original line number Diff line number Diff line
@@ -99,7 +99,11 @@ public class RecoveryController { 
    public static final int ERROR_SESSION_EXPIRED = 24;



    /**

     * Failed because the provided certificate was not a valid X509 certificate.

     * Failed because the format of the provided certificate is incorrect, e.g., cannot be decoded

     * properly or misses necessary fields.

     *

     * <p>Note that this is different from {@link #ERROR_INVALID_CERTIFICATE}, which implies the

     * certificate has a correct format but cannot be validated.

     *

     * @hide

     */
@@ -121,6 +125,16 @@ public class RecoveryController { 
     */

    public static final int ERROR_INVALID_KEY_FORMAT = 27;



    /**

     * Failed because the provided certificate cannot be validated, e.g., is expired or has invalid

     * signatures.

     *

     * <p>Note that this is different from {@link #ERROR_BAD_CERTIFICATE_FORMAT}, which denotes

     * incorrect certificate formats, e.g., due to wrong encoding or structure.

     *

     * @hide

     */

    public static final int ERROR_INVALID_CERTIFICATE = 28;



    private final ILockSettings mBinder;

    private final KeyStore mKeyStore;
@@ -149,23 +163,9 @@ public class RecoveryController { 
    }



    /**

     * Initializes key recovery service for the calling application. RecoveryController

     * randomly chooses one of the keys from the list and keeps it to use for future key export

     * operations. Collection of all keys in the list must be signed by the provided {@code

     * rootCertificateAlias}, which must also be present in the list of root certificates

     * preinstalled on the device. The random selection allows RecoveryController to select

     * which of a set of remote recovery service devices will be used.

     *

     * <p>In addition, RecoveryController enforces a delay of three months between

     * consecutive initialization attempts, to limit the ability of an attacker to often switch

     * remote recovery devices and significantly increase number of recovery attempts.

     *

     * @param rootCertificateAlias alias of a root certificate preinstalled on the device

     * @param signedPublicKeyList binary blob a list of X509 certificates and signature

     * @throws CertificateException if the {@code signedPublicKeyList} is in a bad format.

     * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery

     *     service.

     * @deprecated Use {@link #initRecoveryService(String, byte[], byte[])} instead.

     */

    @Deprecated

    @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE)

    public void initRecoveryService(

            @NonNull String rootCertificateAlias, @NonNull byte[] signedPublicKeyList)
@@ -175,7 +175,54 @@ public class RecoveryController { 
        } catch (RemoteException e) {

            throw e.rethrowFromSystemServer();

        } catch (ServiceSpecificException e) {

            if (e.errorCode == ERROR_BAD_CERTIFICATE_FORMAT) {

            if (e.errorCode == ERROR_BAD_CERTIFICATE_FORMAT

                    || e.errorCode == ERROR_INVALID_CERTIFICATE) {

                throw new CertificateException(e.getMessage());

            }

            throw wrapUnexpectedServiceSpecificException(e);

        }

    }



    /**

     * Initializes the recovery service for the calling application. The detailed steps should be:

     * <ol>

     *     <li>Parse {@code signatureFile} to get relevant information.

     *     <li>Validate the signer's X509 certificate, contained in {@code signatureFile}, against

     *         the root certificate pre-installed in the OS and chosen by {@code

     *         rootCertificateAlias}.

     *     <li>Verify the public-key signature, contained in {@code signatureFile}, and verify it

     *         against the entire {@code certificateFile}.

     *     <li>Parse {@code certificateFile} to get relevant information.

     *     <li>Check the serial number, contained in {@code certificateFile}, and skip the following

     *         steps if the serial number is not larger than the one previously stored.

     *     <li>Randomly choose a X509 certificate from the endpoint X509 certificates, contained in

     *         {@code certificateFile}, and validate it against the root certificate pre-installed

     *         in the OS and chosen by {@code rootCertificateAlias}.

     *     <li>Store the chosen X509 certificate and the serial in local database for later use.

     * </ol>

     *

     * @param rootCertificateAlias the alias of a root certificate pre-installed in the OS

     * @param certificateFile the binary content of the XML file containing a list of recovery

     *     service X509 certificates, and other metadata including the serial number

     * @param signatureFile the binary content of the XML file containing the public-key signature

     *     of the entire certificate file, and a signer's X509 certificate

     * @throws CertificateException if the given certificate files cannot be parsed or validated

     * @throws InternalRecoveryServiceException if an unexpected error occurred in the recovery

     *     service.

     */

    @RequiresPermission(android.Manifest.permission.RECOVER_KEYSTORE)

    public void initRecoveryService(

            @NonNull String rootCertificateAlias, @NonNull byte[] certificateFile,

            @NonNull byte[] signatureFile)

            throws CertificateException, InternalRecoveryServiceException {

        try {

            mBinder.initRecoveryServiceWithSigFile(

                    rootCertificateAlias, certificateFile, signatureFile);

        } catch (RemoteException e) {

            throw e.rethrowFromSystemServer();

        } catch (ServiceSpecificException e) {

            if (e.errorCode == ERROR_BAD_CERTIFICATE_FORMAT

                    || e.errorCode == ERROR_INVALID_CERTIFICATE) {

                throw new CertificateException(e.getMessage());

            }

            throw wrapUnexpectedServiceSpecificException(e);

core/java/android/security/keystore/recovery/RecoverySession.java

+4 −2
Original line number Diff line number Diff line
@@ -94,7 +94,8 @@ public class RecoverySession implements AutoCloseable { 
        } catch (RemoteException e) {

            throw e.rethrowFromSystemServer();

        } catch (ServiceSpecificException e) {

            if (e.errorCode == RecoveryController.ERROR_BAD_CERTIFICATE_FORMAT) {

            if (e.errorCode == RecoveryController.ERROR_BAD_CERTIFICATE_FORMAT

                    || e.errorCode == RecoveryController.ERROR_INVALID_CERTIFICATE) {

                throw new CertificateException(e.getMessage());

            }

            throw mRecoveryController.wrapUnexpectedServiceSpecificException(e);
@@ -143,7 +144,8 @@ public class RecoverySession implements AutoCloseable { 
        } catch (RemoteException e) {

            throw e.rethrowFromSystemServer();

        } catch (ServiceSpecificException e) {

            if (e.errorCode == RecoveryController.ERROR_BAD_CERTIFICATE_FORMAT) {

            if (e.errorCode == RecoveryController.ERROR_BAD_CERTIFICATE_FORMAT

                    || e.errorCode == RecoveryController.ERROR_INVALID_CERTIFICATE) {

                throw new CertificateException(e.getMessage());

            }

            throw mRecoveryController.wrapUnexpectedServiceSpecificException(e);

core/java/com/android/internal/widget/ILockSettings.aidl

+2 −0
Original line number Diff line number Diff line
@@ -65,6 +65,8 @@ interface ILockSettings { 
    // {@code ServiceSpecificException} may be thrown to signal an error, which caller can

    // convert to  {@code RecoveryManagerException}.

    void initRecoveryService(in String rootCertificateAlias, in byte[] signedPublicKeyList);

    void initRecoveryServiceWithSigFile(in String rootCertificateAlias,

            in byte[] recoveryServiceCertFile, in byte[] recoveryServiceSigFile);

    KeyChainSnapshot getKeyChainSnapshot();

    byte[] generateAndStoreKey(String alias);

    String generateKey(String alias);

services/core/java/com/android/server/locksettings/LockSettingsService.java

+8 −0
Original line number Diff line number Diff line
@@ -1982,6 +1982,14 @@ public class LockSettingsService extends ILockSettings.Stub { 
                signedPublicKeyList);

    }



    @Override

    public void initRecoveryServiceWithSigFile(@NonNull String rootCertificateAlias,

            @NonNull byte[] recoveryServiceCertFile, @NonNull byte[] recoveryServiceSigFile)

            throws RemoteException {

        mRecoverableKeyStoreManager.initRecoveryServiceWithSigFile(rootCertificateAlias,

                recoveryServiceCertFile, recoveryServiceSigFile);

    }



    @Override

    public KeyChainSnapshot getKeyChainSnapshot() throws RemoteException {

        return mRecoverableKeyStoreManager.getKeyChainSnapshot();