1 /* 2 * Copyright (C) 2019 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.integrity; 18 19 import static com.android.internal.util.Preconditions.checkArgument; 20 21 import android.annotation.IntDef; 22 import android.annotation.NonNull; 23 import android.annotation.Nullable; 24 import android.annotation.SystemApi; 25 import android.os.Parcel; 26 import android.os.Parcelable; 27 28 import com.android.internal.annotations.VisibleForTesting; 29 30 import java.lang.annotation.Retention; 31 import java.lang.annotation.RetentionPolicy; 32 import java.util.Objects; 33 34 /** 35 * Represent rules to be used in the rule evaluation engine to match against app installs. 36 * 37 * <p>Instances of this class are immutable. 38 * 39 * @hide 40 */ 41 @SystemApi 42 @VisibleForTesting 43 public final class Rule implements Parcelable { 44 45 /** @hide */ 46 @IntDef( 47 value = { 48 DENY, 49 FORCE_ALLOW, 50 }) 51 @Retention(RetentionPolicy.SOURCE) 52 public @interface Effect {} 53 54 /** If this rule matches the install, the install should be denied. */ 55 public static final int DENY = 0; 56 57 /** 58 * If this rule matches the install, the install will be allowed regardless of other matched 59 * rules. 60 */ 61 public static final int FORCE_ALLOW = 1; 62 63 private final @NonNull IntegrityFormula mFormula; 64 private final @Effect int mEffect; 65 Rule(@onNull IntegrityFormula formula, @Effect int effect)66 public Rule(@NonNull IntegrityFormula formula, @Effect int effect) { 67 checkArgument(isValidEffect(effect), "Unknown effect: %d", effect); 68 this.mFormula = Objects.requireNonNull(formula); 69 this.mEffect = effect; 70 } 71 Rule(Parcel in)72 Rule(Parcel in) { 73 mFormula = IntegrityFormula.readFromParcel(in); 74 mEffect = in.readInt(); 75 } 76 77 @NonNull 78 public static final Creator<Rule> CREATOR = 79 new Creator<Rule>() { 80 @Override 81 public Rule createFromParcel(Parcel in) { 82 return new Rule(in); 83 } 84 85 @Override 86 public Rule[] newArray(int size) { 87 return new Rule[size]; 88 } 89 }; 90 91 @Override describeContents()92 public int describeContents() { 93 return 0; 94 } 95 96 @Override writeToParcel(@onNull Parcel dest, int flags)97 public void writeToParcel(@NonNull Parcel dest, int flags) { 98 IntegrityFormula.writeToParcel(mFormula, dest, flags); 99 dest.writeInt(mEffect); 100 } 101 102 @NonNull getFormula()103 public IntegrityFormula getFormula() { 104 return mFormula; 105 } 106 getEffect()107 public @Effect int getEffect() { 108 return mEffect; 109 } 110 111 @Override toString()112 public String toString() { 113 return String.format("Rule: %s, %s", mFormula, effectToString(mEffect)); 114 } 115 116 @Override equals(@ullable Object o)117 public boolean equals(@Nullable Object o) { 118 if (this == o) { 119 return true; 120 } 121 if (o == null || getClass() != o.getClass()) { 122 return false; 123 } 124 Rule that = (Rule) o; 125 return mEffect == that.mEffect && Objects.equals(mFormula, that.mFormula); 126 } 127 128 @Override hashCode()129 public int hashCode() { 130 return Objects.hash(mFormula, mEffect); 131 } 132 effectToString(int effect)133 private static String effectToString(int effect) { 134 switch (effect) { 135 case DENY: 136 return "DENY"; 137 case FORCE_ALLOW: 138 return "FORCE_ALLOW"; 139 default: 140 throw new IllegalArgumentException("Unknown effect " + effect); 141 } 142 } 143 isValidEffect(int effect)144 private static boolean isValidEffect(int effect) { 145 return effect == DENY || effect == FORCE_ALLOW; 146 } 147 } 148