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      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.content.pm;
     18 
     19 import android.os.Parcel;
     20 import android.os.Parcelable;
     21 import android.text.TextUtils;
     22 import android.util.Slog;
     23 
     24 import java.security.InvalidAlgorithmParameterException;
     25 import java.security.spec.AlgorithmParameterSpec;
     26 import java.util.Arrays;
     27 
     28 import javax.crypto.SecretKey;
     29 import javax.crypto.spec.IvParameterSpec;
     30 
     31 /**
     32  * Represents encryption parameters used to read a container.
     33  *
     34  * @hide
     35  */
     36 public class ContainerEncryptionParams implements Parcelable {
     37     protected static final String TAG = "ContainerEncryptionParams";
     38 
     39     /** What we print out first when toString() is called. */
     40     private static final String TO_STRING_PREFIX = "ContainerEncryptionParams{";
     41 
     42     /**
     43      * Parameter type for parceling that indicates the next parameters are
     44      * IvParameters.
     45      */
     46     private static final int ENC_PARAMS_IV_PARAMETERS = 1;
     47 
     48     /** Parameter type for paceling that indicates there are no MAC parameters. */
     49     private static final int MAC_PARAMS_NONE = 1;
     50 
     51     /** The encryption algorithm used. */
     52     private final String mEncryptionAlgorithm;
     53 
     54     /** The parameter spec to be used for encryption. */
     55     private final IvParameterSpec mEncryptionSpec;
     56 
     57     /** Secret key to be used for decryption. */
     58     private final SecretKey mEncryptionKey;
     59 
     60     /** Algorithm name for the MAC to be used. */
     61     private final String mMacAlgorithm;
     62 
     63     /** The parameter spec to be used for the MAC tag authentication. */
     64     private final AlgorithmParameterSpec mMacSpec;
     65 
     66     /** Secret key to be used for MAC tag authentication. */
     67     private final SecretKey mMacKey;
     68 
     69     /** MAC tag authenticating the data in the container. */
     70     private final byte[] mMacTag;
     71 
     72     /** Offset into file where authenticated (e.g., MAC protected) data begins. */
     73     private final long mAuthenticatedDataStart;
     74 
     75     /** Offset into file where encrypted data begins. */
     76     private final long mEncryptedDataStart;
     77 
     78     /**
     79      * Offset into file for the end of encrypted data (and, by extension,
     80      * authenticated data) in file.
     81      */
     82     private final long mDataEnd;
     83 
     84     public ContainerEncryptionParams(String encryptionAlgorithm,
     85             AlgorithmParameterSpec encryptionSpec, SecretKey encryptionKey)
     86             throws InvalidAlgorithmParameterException {
     87         this(encryptionAlgorithm, encryptionSpec, encryptionKey, null, null, null, null, -1, -1,
     88                 -1);
     89     }
     90 
     91     /**
     92      * Creates container encryption specifications for installing from encrypted
     93      * containers.
     94      *
     95      * @param encryptionAlgorithm encryption algorithm to use; format matches
     96      *            JCE
     97      * @param encryptionSpec algorithm parameter specification
     98      * @param encryptionKey key used for decryption
     99      * @param macAlgorithm MAC algorithm to use; format matches JCE
    100      * @param macSpec algorithm parameters specification, may be {@code null}
    101      * @param macKey key used for authentication (i.e., for the MAC tag)
    102      * @param macTag message authentication code (MAC) tag for the authenticated
    103      *            data
    104      * @param authenticatedDataStart offset of start of authenticated data in
    105      *            stream
    106      * @param encryptedDataStart offset of start of encrypted data in stream
    107      * @param dataEnd offset of the end of both the authenticated and encrypted
    108      *            data
    109      * @throws InvalidAlgorithmParameterException
    110      */
    111     public ContainerEncryptionParams(String encryptionAlgorithm,
    112             AlgorithmParameterSpec encryptionSpec, SecretKey encryptionKey, String macAlgorithm,
    113             AlgorithmParameterSpec macSpec, SecretKey macKey, byte[] macTag,
    114             long authenticatedDataStart, long encryptedDataStart, long dataEnd)
    115             throws InvalidAlgorithmParameterException {
    116         if (TextUtils.isEmpty(encryptionAlgorithm)) {
    117             throw new NullPointerException("algorithm == null");
    118         } else if (encryptionSpec == null) {
    119             throw new NullPointerException("encryptionSpec == null");
    120         } else if (encryptionKey == null) {
    121             throw new NullPointerException("encryptionKey == null");
    122         }
    123 
    124         if (!TextUtils.isEmpty(macAlgorithm)) {
    125             if (macKey == null) {
    126                 throw new NullPointerException("macKey == null");
    127             }
    128         }
    129 
    130         if (!(encryptionSpec instanceof IvParameterSpec)) {
    131             throw new InvalidAlgorithmParameterException(
    132                     "Unknown parameter spec class; must be IvParameters");
    133         }
    134 
    135         mEncryptionAlgorithm = encryptionAlgorithm;
    136         mEncryptionSpec = (IvParameterSpec) encryptionSpec;
    137         mEncryptionKey = encryptionKey;
    138 
    139         mMacAlgorithm = macAlgorithm;
    140         mMacSpec = macSpec;
    141         mMacKey = macKey;
    142         mMacTag = macTag;
    143 
    144         mAuthenticatedDataStart = authenticatedDataStart;
    145         mEncryptedDataStart = encryptedDataStart;
    146         mDataEnd = dataEnd;
    147     }
    148 
    149     public String getEncryptionAlgorithm() {
    150         return mEncryptionAlgorithm;
    151     }
    152 
    153     public AlgorithmParameterSpec getEncryptionSpec() {
    154         return mEncryptionSpec;
    155     }
    156 
    157     public SecretKey getEncryptionKey() {
    158         return mEncryptionKey;
    159     }
    160 
    161     public String getMacAlgorithm() {
    162         return mMacAlgorithm;
    163     }
    164 
    165     public AlgorithmParameterSpec getMacSpec() {
    166         return mMacSpec;
    167     }
    168 
    169     public SecretKey getMacKey() {
    170         return mMacKey;
    171     }
    172 
    173     public byte[] getMacTag() {
    174         return mMacTag;
    175     }
    176 
    177     public long getAuthenticatedDataStart() {
    178         return mAuthenticatedDataStart;
    179     }
    180 
    181     public long getEncryptedDataStart() {
    182         return mEncryptedDataStart;
    183     }
    184 
    185     public long getDataEnd() {
    186         return mDataEnd;
    187     }
    188 
    189     @Override
    190     public int describeContents() {
    191         return 0;
    192     }
    193 
    194     @Override
    195     public boolean equals(Object o) {
    196         if (this == o) {
    197             return true;
    198         }
    199 
    200         if (!(o instanceof ContainerEncryptionParams)) {
    201             return false;
    202         }
    203 
    204         final ContainerEncryptionParams other = (ContainerEncryptionParams) o;
    205 
    206         // Primitive comparison
    207         if ((mAuthenticatedDataStart != other.mAuthenticatedDataStart)
    208                 || (mEncryptedDataStart != other.mEncryptedDataStart)
    209                 || (mDataEnd != other.mDataEnd)) {
    210             return false;
    211         }
    212 
    213         // String comparison
    214         if (!mEncryptionAlgorithm.equals(other.mEncryptionAlgorithm)
    215                 || !mMacAlgorithm.equals(other.mMacAlgorithm)) {
    216             return false;
    217         }
    218 
    219         // Object comparison
    220         if (!isSecretKeyEqual(mEncryptionKey, other.mEncryptionKey)
    221                 || !isSecretKeyEqual(mMacKey, other.mMacKey)) {
    222             return false;
    223         }
    224 
    225         if (!Arrays.equals(mEncryptionSpec.getIV(), other.mEncryptionSpec.getIV())
    226                 || !Arrays.equals(mMacTag, other.mMacTag) || (mMacSpec != other.mMacSpec)) {
    227             return false;
    228         }
    229 
    230         return true;
    231     }
    232 
    233     private static final boolean isSecretKeyEqual(SecretKey key1, SecretKey key2) {
    234         final String keyFormat = key1.getFormat();
    235         final String otherKeyFormat = key2.getFormat();
    236 
    237         if (keyFormat == null) {
    238             if (keyFormat != otherKeyFormat) {
    239                 return false;
    240             }
    241 
    242             if (key1.getEncoded() != key2.getEncoded()) {
    243                 return false;
    244             }
    245         } else {
    246             if (!keyFormat.equals(key2.getFormat())) {
    247                 return false;
    248             }
    249 
    250             if (!Arrays.equals(key1.getEncoded(), key2.getEncoded())) {
    251                 return false;
    252             }
    253         }
    254 
    255         return true;
    256     }
    257 
    258     @Override
    259     public int hashCode() {
    260         int hash = 3;
    261 
    262         hash += 5 * mEncryptionAlgorithm.hashCode();
    263         hash += 7 * Arrays.hashCode(mEncryptionSpec.getIV());
    264         hash += 11 * mEncryptionKey.hashCode();
    265         hash += 13 * mMacAlgorithm.hashCode();
    266         hash += 17 * mMacKey.hashCode();
    267         hash += 19 * Arrays.hashCode(mMacTag);
    268         hash += 23 * mAuthenticatedDataStart;
    269         hash += 29 * mEncryptedDataStart;
    270         hash += 31 * mDataEnd;
    271 
    272         return hash;
    273     }
    274 
    275     @Override
    276     public String toString() {
    277         final StringBuilder sb = new StringBuilder(TO_STRING_PREFIX);
    278 
    279         sb.append("mEncryptionAlgorithm=\"");
    280         sb.append(mEncryptionAlgorithm);
    281         sb.append("\",");
    282         sb.append("mEncryptionSpec=");
    283         sb.append(mEncryptionSpec.toString());
    284         sb.append("mEncryptionKey=");
    285         sb.append(mEncryptionKey.toString());
    286 
    287         sb.append("mMacAlgorithm=\"");
    288         sb.append(mMacAlgorithm);
    289         sb.append("\",");
    290         sb.append("mMacSpec=");
    291         sb.append(mMacSpec.toString());
    292         sb.append("mMacKey=");
    293         sb.append(mMacKey.toString());
    294 
    295         sb.append(",mAuthenticatedDataStart=");
    296         sb.append(mAuthenticatedDataStart);
    297         sb.append(",mEncryptedDataStart=");
    298         sb.append(mEncryptedDataStart);
    299         sb.append(",mDataEnd=");
    300         sb.append(mDataEnd);
    301         sb.append('}');
    302 
    303         return sb.toString();
    304     }
    305 
    306     @Override
    307     public void writeToParcel(Parcel dest, int flags) {
    308         dest.writeString(mEncryptionAlgorithm);
    309         dest.writeInt(ENC_PARAMS_IV_PARAMETERS);
    310         dest.writeByteArray(mEncryptionSpec.getIV());
    311         dest.writeSerializable(mEncryptionKey);
    312 
    313         dest.writeString(mMacAlgorithm);
    314         dest.writeInt(MAC_PARAMS_NONE);
    315         dest.writeByteArray(new byte[0]);
    316         dest.writeSerializable(mMacKey);
    317 
    318         dest.writeByteArray(mMacTag);
    319 
    320         dest.writeLong(mAuthenticatedDataStart);
    321         dest.writeLong(mEncryptedDataStart);
    322         dest.writeLong(mDataEnd);
    323     }
    324 
    325     private ContainerEncryptionParams(Parcel source) throws InvalidAlgorithmParameterException {
    326         mEncryptionAlgorithm = source.readString();
    327         final int encParamType = source.readInt();
    328         final byte[] encParamsEncoded = source.createByteArray();
    329         mEncryptionKey = (SecretKey) source.readSerializable();
    330 
    331         mMacAlgorithm = source.readString();
    332         final int macParamType = source.readInt();
    333         source.createByteArray(); // byte[] macParamsEncoded
    334         mMacKey = (SecretKey) source.readSerializable();
    335 
    336         mMacTag = source.createByteArray();
    337 
    338         mAuthenticatedDataStart = source.readLong();
    339         mEncryptedDataStart = source.readLong();
    340         mDataEnd = source.readLong();
    341 
    342         switch (encParamType) {
    343             case ENC_PARAMS_IV_PARAMETERS:
    344                 mEncryptionSpec = new IvParameterSpec(encParamsEncoded);
    345                 break;
    346             default:
    347                 throw new InvalidAlgorithmParameterException("Unknown parameter type "
    348                         + encParamType);
    349         }
    350 
    351         switch (macParamType) {
    352             case MAC_PARAMS_NONE:
    353                 mMacSpec = null;
    354                 break;
    355             default:
    356                 throw new InvalidAlgorithmParameterException("Unknown parameter type "
    357                         + macParamType);
    358         }
    359 
    360         if (mEncryptionKey == null) {
    361             throw new NullPointerException("encryptionKey == null");
    362         }
    363     }
    364 
    365     public static final Parcelable.Creator<ContainerEncryptionParams> CREATOR =
    366             new Parcelable.Creator<ContainerEncryptionParams>() {
    367         public ContainerEncryptionParams createFromParcel(Parcel source) {
    368             try {
    369                 return new ContainerEncryptionParams(source);
    370             } catch (InvalidAlgorithmParameterException e) {
    371                 Slog.e(TAG, "Invalid algorithm parameters specified", e);
    372                 return null;
    373             }
    374         }
    375 
    376         public ContainerEncryptionParams[] newArray(int size) {
    377             return new ContainerEncryptionParams[size];
    378         }
    379     };
    380 }