Implement system signature spoofing

Devices with unsigned custom ROMs (signed with test keys) should pass Device verdict.

Co-authored-by: 4h9fbZ <7454974439@proton.me>

app/proguard-rules.pro

@@ -1,3 +1,5 @@
+-dontobfuscate
 -keep class es.chiteroman.playintegrityfix.EntryPoint {public <methods>;}
 -keep class es.chiteroman.playintegrityfix.CustomKeyStoreSpi
 -keep class es.chiteroman.playintegrityfix.CustomProvider
+-keep class es.chiteroman.playintegrityfix.CustomPackageInfoCreator

app/src/main/java/es/chiteroman/playintegrityfix/CustomPackageInfoCreator.java

@@ -0,0 +1,41 @@
+package es.chiteroman.playintegrityfix;
+
+import android.content.pm.PackageInfo;
+import android.content.pm.Signature;
+import android.os.Build;
+import android.os.Parcel;
+import android.os.Parcelable;
+
+public class CustomPackageInfoCreator implements Parcelable.Creator<PackageInfo> {
+    private final Parcelable.Creator<PackageInfo> originalCreator;
+    private final Signature spoofedSignature;
+
+    public CustomPackageInfoCreator(Parcelable.Creator<PackageInfo> originalCreator, Signature spoofedSignature) {
+        this.originalCreator = originalCreator;
+        this.spoofedSignature = spoofedSignature;
+    }
+
+    @Override
+    public PackageInfo createFromParcel(Parcel source) {
+        PackageInfo packageInfo = originalCreator.createFromParcel(source);
+        if (packageInfo.packageName.equals("android")) {
+            if (packageInfo.signatures != null && packageInfo.signatures.length > 0) {
+                packageInfo.signatures[0] = spoofedSignature;
+            }
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
+                if (packageInfo.signingInfo != null) {
+                    Signature[] signaturesArray = packageInfo.signingInfo.getApkContentsSigners();
+                    if (signaturesArray != null && signaturesArray.length > 0) {
+                        signaturesArray[0] = spoofedSignature;
+                    }
+                }
+            }
+        }
+        return packageInfo;
+    }
+
+    @Override
+    public PackageInfo[] newArray(int size) {
+        return originalCreator.newArray(size);
+    }
+}

app/src/main/java/es/chiteroman/playintegrityfix/EntryPoint.java

@@ -1,22 +1,60 @@
 package es.chiteroman.playintegrityfix;
 
+import android.content.pm.PackageInfo;
+import android.content.pm.PackageManager;
+import android.content.pm.Signature;
 import android.os.Build;
+import android.os.Parcel;
+import android.os.Parcelable;
 import android.text.TextUtils;
+import android.util.Base64;
 import android.util.Log;
 
 import org.json.JSONObject;
+import org.lsposed.hiddenapibypass.HiddenApiBypass;
 
 import java.lang.reflect.Field;
+import java.lang.reflect.Method;
 import java.security.KeyStore;
 import java.security.KeyStoreSpi;
 import java.security.Provider;
 import java.security.Security;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Objects;
 
 public final class EntryPoint {
     public static final String TAG = "PIF";
     private static final Map<Field, String> map = new HashMap<>();
+    private static final String signatureData = """
+            MIIFyTCCA7GgAwIBAgIVALyxxl+zDS9SL68SzOr48309eAZyMA0GCSqGSIb3DQEBCwUAMHQxCzAJ
+            BgNVBAYTAlVTMRMwEQYDVQQIEwpDYWxpZm9ybmlhMRYwFAYDVQQHEw1Nb3VudGFpbiBWaWV3MRQw
+            EgYDVQQKEwtHb29nbGUgSW5jLjEQMA4GA1UECxMHQW5kcm9pZDEQMA4GA1UEAxMHQW5kcm9pZDAg
+            Fw0yMjExMDExODExMzVaGA8yMDUyMTEwMTE4MTEzNVowdDELMAkGA1UEBhMCVVMxEzARBgNVBAgT
+            CkNhbGlmb3JuaWExFjAUBgNVBAcTDU1vdW50YWluIFZpZXcxFDASBgNVBAoTC0dvb2dsZSBJbmMu
+            MRAwDgYDVQQLEwdBbmRyb2lkMRAwDgYDVQQDEwdBbmRyb2lkMIICIjANBgkqhkiG9w0BAQEFAAOC
+            Ag8AMIICCgKCAgEAsqtalIy/nctKlrhd1UVoDffFGnDf9GLi0QQhsVoJkfF16vDDydZJOycG7/kQ
+            ziRZhFdcoMrIYZzzw0ppBjsSe1AiWMuKXwTBaEtxN99S1xsJiW4/QMI6N6kMunydWRMsbJ6aAxi1
+            lVq0bxSwr8Sg/8u9HGVivfdG8OpUM+qjuV5gey5xttNLK3BZDrAlco8RkJZryAD40flmJZrWXJmc
+            r2HhJJUnqG4Z3MSziEgW1u1JnnY3f/BFdgYsA54SgdUGdQP3aqzSjIpGK01/vjrXvifHazSANjvl
+            0AUE5i6AarMw2biEKB2ySUDp8idC5w12GpqDrhZ/QkW8yBSa87KbkMYXuRA2Gq1fYbQx3YJraw0U
+            gZ4M3fFKpt6raxxM5j0sWHlULD7dAZMERvNESVrKG3tQ7B39WAD8QLGYc45DFEGOhKv5Fv8510h5
+            sXK502IvGpI4FDwz2rbtAgJ0j+16db5wCSW5ThvNPhCheyciajc8dU1B5tJzZN/ksBpzne4Xf9gO
+            LZ9ZU0+3Z5gHVvTS/YpxBFwiFpmL7dvGxew0cXGSsG5UTBlgr7i0SX0WhY4Djjo8IfPwrvvA0QaC
+            FamdYXKqBsSHgEyXS9zgGIFPt2jWdhaS+sAa//5SXcWro0OdiKPuwEzLgj759ke1sHRnvO735dYn
+            5whVbzlGyLBh3L0CAwEAAaNQME4wDAYDVR0TBAUwAwEB/zAdBgNVHQ4EFgQUU1eXQ7NoYKjvOQlh
+            5V8jHQMoxA8wHwYDVR0jBBgwFoAUU1eXQ7NoYKjvOQlh5V8jHQMoxA8wDQYJKoZIhvcNAQELBQAD
+            ggIBAHFIazRLs3itnZKllPnboSd6sHbzeJURKehx8GJPvIC+xWlwWyFO5+GHmgc3yh/SVd3Xja/k
+            8Ud59WEYTjyJJWTw0Jygx37rHW7VGn2HDuy/x0D+els+S8HeLD1toPFMepjIXJn7nHLhtmzTPlDW
+            DrhiaYsls/k5Izf89xYnI4euuOY2+1gsweJqFGfbznqyqy8xLyzoZ6bvBJtgeY+G3i/9Be14HseS
+            Na4FvI1Oze/l2gUu1IXzN6DGWR/lxEyt+TncJfBGKbjafYrfSh3zsE4N3TU7BeOL5INirOMjre/j
+            VgB1YQG5qLVaPoz6mdn75AbBBm5a5ahApLiKqzy/hP+1rWgw8Ikb7vbUqov/bnY3IlIU6XcPJTCD
+            b9aRZQkStvYpQd82XTyxD/T0GgRLnUj5Uv6iZlikFx1KNj0YNS2T3gyvL++J9B0Y6gAkiG0EtNpl
+            z7Pomsv5pVdmHVdKMjqWw5/6zYzVmu5cXFtR384Ti1qwML1xkD6TC3VIv88rKIEjrkY2c+v1frh9
+            fRJ2OmzXmML9NgHTjEiJR2Ib2iNrMKxkuTIs9oxKZgrJtJKvdU9qJJKM5PnZuNuHhGs6A/9gt9Oc
+            cetYeQvVSqeEmQluWfcunQn9C9Vwi2BJIiVJh4IdWZf5/e2PlSSQ9CJjz2bKI17pzdxOmjQfE0JS
+            F7Xt
+            """;
 
     static {
         try {
@@ -37,6 +75,67 @@ public final class EntryPoint {
 
         Security.removeProvider("AndroidKeyStore");
         Security.insertProviderAt(customProvider, 1);
+
+        spoofPackageManager();
+    }
+
+    private static void spoofPackageManager() {
+        Signature spoofedSignature = new Signature(Base64.decode(signatureData, Base64.DEFAULT));
+        Parcelable.Creator<PackageInfo> originalCreator = PackageInfo.CREATOR;
+        Parcelable.Creator<PackageInfo> customCreator = new CustomPackageInfoCreator(originalCreator, spoofedSignature);
+
+        try {
+            Field creatorField = findField(PackageInfo.class, "CREATOR");
+            creatorField.setAccessible(true);
+            creatorField.set(null, customCreator);
+        } catch (Exception e) {
+            Log.e(TAG, "Couldn't replace PackageInfoCreator: " + e);
+        }
+
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
+            HiddenApiBypass.addHiddenApiExemptions("Landroid/os/Parcel;", "Landroid/content/pm", "Landroid/app");
+        }
+
+        try {
+            Field cacheField = findField(PackageManager.class, "sPackageInfoCache");
+            cacheField.setAccessible(true);
+            Object cache = cacheField.get(null);
+            if (cache != null) {
+                Method clearMethod = cache.getClass().getMethod("clear");
+                clearMethod.invoke(cache);
+            }
+        } catch (Exception e) {
+            Log.e(TAG, "Couldn't clear PackageInfoCache: " + e);
+        }
+
+        try {
+            Field creatorsField = findField(Parcel.class, "mCreators");
+            creatorsField.setAccessible(true);
+            Map<?, ?> mCreators = (Map<?, ?>) creatorsField.get(null);
+            if (mCreators != null) mCreators.clear();
+        } catch (Exception e) {
+            Log.e(TAG, "Couldn't clear Parcel mCreators: " + e);
+        }
+
+        try {
+            Field creatorsField = findField(Parcel.class, "sPairedCreators");
+            creatorsField.setAccessible(true);
+            Map<?, ?> sPairedCreators = (Map<?, ?>) creatorsField.get(null);
+            if (sPairedCreators != null) sPairedCreators.clear();
+        } catch (Exception e) {
+            Log.e(TAG, "Couldn't clear Parcel sPairedCreators: " + e);
+        }
+    }
+
+    private static Field findField(Class<?> currentClass, String fieldName) throws NoSuchFieldException {
+        while (currentClass != null && !currentClass.equals(Object.class)) {
+            try {
+                return currentClass.getDeclaredField(fieldName);
+            } catch (NoSuchFieldException e) {
+                currentClass = currentClass.getSuperclass();
+            }
+        }
+        throw new NoSuchFieldException("Field '" + fieldName + "' not found in class hierarchy of " + Objects.requireNonNull(currentClass).getName());
     }
 
     public static void init(String json) {