From 0033c65aa995484ea6aeaa983c1a227fd14b30a5 Mon Sep 17 00:00:00 2001
From: Jackal Guo <jackalguo@google.com>
Date: Wed, 22 Dec 2021 09:46:15 +0800
Subject: [PATCH] Add enforcement for duplicate permissions

Declaring duplicate permissions with different protection levels is
not allowed. Add the scheme enforcement for manifest during parsing.

Bug: 211934395
Test: atest AppSecurityTests
Change-Id: Ieb006ab4abf19baf949e9b5bfd3e3fea16237527
---
 .../pm/parsing/ParsingPackageUtils.java       |  8 ++++++
 .../component/ParsedPermissionUtils.java      | 27 +++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/core/java/android/content/pm/parsing/ParsingPackageUtils.java b/core/java/android/content/pm/parsing/ParsingPackageUtils.java
index 16deaa05afcea..f336672ffefae 100644
--- a/core/java/android/content/pm/parsing/ParsingPackageUtils.java
+++ b/core/java/android/content/pm/parsing/ParsingPackageUtils.java
@@ -21,6 +21,7 @@ import static android.content.pm.ActivityInfo.RESIZE_MODE_UNRESIZEABLE;
 import static android.content.pm.PackageManager.INSTALL_FAILED_INVALID_APK;
 import static android.content.pm.PackageManager.INSTALL_PARSE_FAILED_BAD_MANIFEST;
 import static android.content.pm.PackageManager.INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES;
+import static android.content.pm.PackageManager.INSTALL_PARSE_FAILED_MANIFEST_MALFORMED;
 import static android.content.pm.PackageManager.INSTALL_PARSE_FAILED_NOT_APK;
 import static android.content.pm.PackageManager.INSTALL_PARSE_FAILED_ONLY_COREAPP_ALLOWED;
 import static android.content.pm.PackageManager.INSTALL_PARSE_FAILED_RESOURCES_ARSC_COMPRESSED;
@@ -934,6 +935,13 @@ public class ParsingPackageUtils {
             );
         }
 
+        if (ParsedPermissionUtils.declareDuplicatePermission(pkg)) {
+            return input.error(
+                    INSTALL_PARSE_FAILED_MANIFEST_MALFORMED,
+                    "Declare duplicate permissions with different protection levels."
+            );
+        }
+
         convertCompatPermissions(pkg);
 
         convertSplitPermissions(pkg);
diff --git a/core/java/android/content/pm/parsing/component/ParsedPermissionUtils.java b/core/java/android/content/pm/parsing/component/ParsedPermissionUtils.java
index 66e9d3ddca1f1..86c8f02f9fd94 100644
--- a/core/java/android/content/pm/parsing/component/ParsedPermissionUtils.java
+++ b/core/java/android/content/pm/parsing/component/ParsedPermissionUtils.java
@@ -27,6 +27,7 @@ import android.content.pm.parsing.result.ParseResult;
 import android.content.res.Resources;
 import android.content.res.TypedArray;
 import android.content.res.XmlResourceParser;
+import android.util.ArrayMap;
 import android.util.Slog;
 
 import com.android.internal.R;
@@ -34,6 +35,7 @@ import com.android.internal.R;
 import org.xmlpull.v1.XmlPullParserException;
 
 import java.io.IOException;
+import java.util.List;
 
 /** @hide */
 public class ParsedPermissionUtils {
@@ -271,4 +273,29 @@ public class ParsedPermissionUtils {
         }
         return size;
     }
+
+    /**
+     * @return {@code true} if the package declares duplicate permissions with different
+     * protection levels.
+     */
+    public static boolean declareDuplicatePermission(@NonNull ParsingPackage pkg) {
+        final List<ParsedPermission> permissions = pkg.getPermissions();
+        final int size = permissions.size();
+        if (size > 0) {
+            final ArrayMap<String, ParsedPermission> checkDuplicatePerm = new ArrayMap<>(size);
+            for (int i = 0; i < size; i++) {
+                final ParsedPermission parsedPermission = permissions.get(i);
+                final String name = parsedPermission.getName();
+                final ParsedPermission perm = checkDuplicatePerm.get(name);
+                // Since a permission tree is also added as a permission with normal protection
+                // level, we need to skip if the parsedPermission is a permission tree.
+                if (perm != null && !(perm.isTree() || parsedPermission.isTree())
+                        && perm.getProtectionLevel() != parsedPermission.getProtectionLevel()) {
+                    return true;
+                }
+                checkDuplicatePerm.put(name, parsedPermission);
+            }
+        }
+        return false;
+    }
 }