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Commit aa32d153 authored by Rubin Xu's avatar Rubin Xu
Browse files

Invoke BLKSECDISCARD to securely delete sensitive data 

Bug: 34600579
Test: manual - change device lock under synthetic password, verify
      old data on disk is erased.

Change-Id: I247bd1f095dd27335e671981f9e2d77e149af84f
parent 74fa79e6

core/java/android/os/storage/IStorageManager.aidl

+1 −0
Original line number Diff line number Diff line
@@ -295,4 +295,5 @@ interface IStorageManager { 
    long getCacheSizeBytes(String volumeUuid, int uid) = 76;

    long getAllocatableBytes(String volumeUuid, int flags) = 77;

    void allocateBytes(String volumeUuid, long bytes, int flags) = 78;

    void secdiscard(in String path) = 79;

}

core/java/android/os/storage/StorageManager.java

+9 −0
Original line number Diff line number Diff line
@@ -1251,6 +1251,15 @@ public class StorageManager { 
        }

    }



    /** {@hide} */

    public void secdiscard(String path) {

        try {

            mStorageManager.secdiscard(path);

        } catch (RemoteException e) {

            throw e.rethrowFromSystemServer();

        }

    }



    /** {@hide} */

    public static boolean isUserKeyUnlocked(int userId) {

        if (sStorageManager == null) {

services/core/java/com/android/server/StorageManagerService.java

+12 −0
Original line number Diff line number Diff line
@@ -3009,6 +3009,18 @@ class StorageManagerService extends IStorageManager.Stub 
        }

    }



    @Override

    public void secdiscard(String path) {

        enforcePermission(android.Manifest.permission.STORAGE_INTERNAL);

        waitForReady();



        try {

            mCryptConnector.execute("cryptfs", "secdiscard", escapeNull(path));

        } catch (NativeDaemonConnectorException e) {

            throw e.rethrowAsParcelableException();

        }

    }



    class AppFuseMountScope extends AppFuseBridge.MountScope {

        boolean opened = false;

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

+14 −5
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteOpenHelper;

import android.os.Environment;

import android.os.UserManager;

import android.os.storage.StorageManager;

import android.util.ArrayMap;

import android.util.Log;

import android.util.Slog;
@@ -339,8 +340,11 @@ class LockSettingsStorage { 
        synchronized (mFileWriteLock) {

            RandomAccessFile raf = null;

            try {

                // Write the hash to file

                raf = new RandomAccessFile(name, "rw");

                // Write the hash to file, requiring each write to be synchronized to the

                // underlying storage device immediately to avoid data loss in case of power loss.

                // This also ensures future secdiscard operation on the file succeeds since the

                // file would have been allocated on flash.

                raf = new RandomAccessFile(name, "rws");

                // Truncate the file if pattern is null, to clear the lock

                if (hash == null || hash.length == 0) {

                    raf.setLength(0);
@@ -435,12 +439,17 @@ class LockSettingsStorage { 
        return readFile(getSynthenticPasswordStateFilePathForUser(userId, handle, name));

    }



    public void deleteSyntheticPasswordState(int userId, long handle, String name, boolean secure) {

    public void deleteSyntheticPasswordState(int userId, long handle, String name) {

        String path = getSynthenticPasswordStateFilePathForUser(userId, handle, name);

        File file = new File(path);

        if (file.exists()) {

            //TODO: (b/34600579) invoke secdiscardable

            try {

                mContext.getSystemService(StorageManager.class).secdiscard(file.getAbsolutePath());

            } catch (Exception e) {

                Slog.w(TAG, "Failed to secdiscard " + path, e);

            } finally {

                file.delete();

            }

            mCache.putFile(path, null);

        }

    }

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

+10 −10
Original line number Diff line number Diff line
@@ -452,7 +452,7 @@ public class SyntheticPasswordManager { 


    // Nuke the SP handle (and as a result, its SID) for the given user.

    public void clearSidForUser(int userId) {

        destroyState(SP_HANDLE_NAME, true, DEFAULT_HANDLE, userId);

        destroyState(SP_HANDLE_NAME, DEFAULT_HANDLE, userId);

    }



    public boolean hasSidForUser(int userId) {
@@ -487,8 +487,8 @@ public class SyntheticPasswordManager { 
    }



    public void destroyEscrowData(int userId) {

        destroyState(SP_E0_NAME, true, DEFAULT_HANDLE, userId);

        destroyState(SP_P1_NAME, true, DEFAULT_HANDLE, userId);

        destroyState(SP_E0_NAME, DEFAULT_HANDLE, userId);

        destroyState(SP_P1_NAME, DEFAULT_HANDLE, userId);

    }



    private int loadWeaverSlot(long handle, int userId) {
@@ -523,7 +523,7 @@ public class SyntheticPasswordManager { 
                Log.w(TAG, "Failed to destroy slot", e);

            }

        }

        destroyState(WEAVER_SLOT_NAME, true, handle, userId);

        destroyState(WEAVER_SLOT_NAME, handle, userId);

    }



    private int getNextAvailableWeaverSlot() {
@@ -877,17 +877,17 @@ public class SyntheticPasswordManager { 


    public void destroyTokenBasedSyntheticPassword(long handle, int userId) {

        destroySyntheticPassword(handle, userId);

        destroyState(SECDISCARDABLE_NAME, true, handle, userId);

        destroyState(SECDISCARDABLE_NAME, handle, userId);

    }



    public void destroyPasswordBasedSyntheticPassword(long handle, int userId) {

        destroySyntheticPassword(handle, userId);

        destroyState(SECDISCARDABLE_NAME, true, handle, userId);

        destroyState(PASSWORD_DATA_NAME, true, handle, userId);

        destroyState(SECDISCARDABLE_NAME, handle, userId);

        destroyState(PASSWORD_DATA_NAME, handle, userId);

    }



    private void destroySyntheticPassword(long handle, int userId) {

        destroyState(SP_BLOB_NAME, true, handle, userId);

        destroyState(SP_BLOB_NAME, handle, userId);

        destroySPBlobKey(getHandleName(handle));

        if (hasState(WEAVER_SLOT_NAME, handle, userId)) {

            destroyWeaverSlot(handle, userId);
@@ -938,8 +938,8 @@ public class SyntheticPasswordManager { 
        mStorage.writeSyntheticPasswordState(userId, handle, stateName, data);

    }



    private void destroyState(String stateName, boolean secure, long handle, int userId) {

        mStorage.deleteSyntheticPasswordState(userId, handle, stateName, secure);

    private void destroyState(String stateName, long handle, int userId) {

        mStorage.deleteSyntheticPasswordState(userId, handle, stateName);

    }



    protected byte[] decryptSPBlob(String blobKeyName, byte[] blob, byte[] applicationId) {