RESTRICT AUTOMERGE Add PermissionMemoryFootprintTest

Adds test which verifies that apps cannot create and absurd number of
permissions, or modify existing permissions to make them absurdly large

Bug: 242537498
Test: atest PermissionMemoryFootprintTest

Change-Id: If16ecb7beb6240c9091ef8d031e6f9d2c4190e6d
Merged-In: If16ecb7beb6240c9091ef8d031e6f9d2c4190e6d
diff --git a/tests/tests/security/AndroidManifest.xml b/tests/tests/security/AndroidManifest.xml
index c6df64e..c6d60bc 100644
--- a/tests/tests/security/AndroidManifest.xml
+++ b/tests/tests/security/AndroidManifest.xml
@@ -18,6 +18,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="android.security.cts">
 
+    <permission-tree android:name="com.android.cts"/>
+
     <uses-permission android:name="android.permission.DISABLE_KEYGUARD" />
     <uses-permission android:name="android.permission.KILL_BACKGROUND_PROCESSES" />
     <uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
diff --git a/tests/tests/security/src/android/security/cts/PermissionMemoryFootprintTest.kt b/tests/tests/security/src/android/security/cts/PermissionMemoryFootprintTest.kt
new file mode 100644
index 0000000..f328dcc
--- /dev/null
+++ b/tests/tests/security/src/android/security/cts/PermissionMemoryFootprintTest.kt
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.security.cts
+
+import android.content.pm.PackageManager
+import android.content.pm.PermissionInfo
+import android.platform.test.annotations.AsbSecurityTest
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.platform.app.InstrumentationRegistry
+import com.android.sts.common.util.StsExtraBusinessLogicTestCase
+import org.junit.Assert
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class PermissionMemoryFootprintTest : StsExtraBusinessLogicTestCase() {
+    companion object {
+        const val MAX_NUM_PERMISSIONS = 32000
+        const val PKG_TREE_NAME = "com.android.cts"
+        val LONG_DESCRIPTION = " ".repeat(MAX_NUM_PERMISSIONS / 10)
+        val SHORT_DESCRIPTION = " ".repeat(MAX_NUM_PERMISSIONS / 100)
+
+        val permInfo = PermissionInfo().apply {
+            labelRes = 1
+            protectionLevel = PermissionInfo.PROTECTION_NORMAL
+        }
+    }
+
+    val packageManager: PackageManager = InstrumentationRegistry.getInstrumentation()
+                    .getTargetContext().packageManager!!
+
+    @Throws(SecurityException::class)
+    private fun createOrRemovePermissions(
+        largePerm: Boolean = true,
+        add: Boolean = true,
+        numPerms: Int = MAX_NUM_PERMISSIONS
+    ): Int {
+        var numPermsCreated = 0
+        for (i in 1..numPerms) {
+            try {
+                permInfo.name = "$PKG_TREE_NAME.$i"
+                permInfo.nonLocalizedDescription = if (largePerm) {
+                    LONG_DESCRIPTION
+                } else {
+                    SHORT_DESCRIPTION
+                }
+
+                if (add) {
+                    packageManager.addPermission(permInfo)
+                } else {
+                    packageManager.removePermission(permInfo.name)
+                }
+            } catch (e: SecurityException) {
+                break
+            }
+            numPermsCreated = i
+        }
+        return numPermsCreated
+    }
+
+    @Test
+    @AsbSecurityTest(cveBugId = [242537498])
+    fun checkAppsCreatingPermissionsAreCapped() {
+        var numCreated = 0
+        try {
+            numCreated = createOrRemovePermissions()
+            Assert.assertNotEquals("Expected at least one permission", numCreated, 0)
+            Assert.assertNotEquals(numCreated, MAX_NUM_PERMISSIONS)
+        } finally {
+            createOrRemovePermissions(add = false, numPerms = numCreated)
+        }
+    }
+
+    @Test
+    @AsbSecurityTest(cveBugId = [242537498])
+    fun checkAppsCantIncreasePermissionSizeAfterCreating() {
+        var numCreatedShort = 0
+        try {
+            numCreatedShort = createOrRemovePermissions(largePerm = false)
+            Assert.assertNotEquals("Expected at least one permission", numCreatedShort, 0)
+            val numCreatedLong = createOrRemovePermissions(numPerms = 1)
+            Assert.assertEquals("Expected to not be able to create a large permission",
+                0, numCreatedLong)
+        } finally {
+            createOrRemovePermissions(add = false, numPerms = numCreatedShort)
+        }
+    }
+}