Add PermissionAnnotationDetector

This detector ensures that all AIDL-generated interfaces are annotated
with one permission annotation (@EnforcePermission,
@NoPermissionRequired, or @PermissionManuallyEnforced). It is part of
the framework linters and disabled by default.

It will be enabled explicitly in a subsequent change (for
services/Android.bp). The baseline of the services will also be updated
to capture the current status of non-annotated interfaces.

Bug: 220214993
Test: atest --host AndroidFrameworkLintCheckerTest
Change-Id: I0fbd41b63465f119d90505153fa3a98c0fcdc798

tools/lint/framework/checks/src/main/java/com/google/android/lint/AndroidFrameworkIssueRegistry.kt

@@ -20,6 +20,7 @@ import com.android.tools.lint.client.api.IssueRegistry
 import com.android.tools.lint.client.api.Vendor
 import com.android.tools.lint.detector.api.CURRENT_API
 import com.google.android.lint.parcel.SaferParcelChecker
+import com.google.android.lint.aidl.PermissionAnnotationDetector
 import com.google.auto.service.AutoService
 
 @AutoService(IssueRegistry::class)
@@ -37,6 +38,7 @@ class AndroidFrameworkIssueRegistry : IssueRegistry() {
         SaferParcelChecker.ISSUE_UNSAFE_API_USAGE,
         // TODO: Currently crashes due to OOM issue
         // PackageVisibilityDetector.ISSUE_PACKAGE_NAME_NO_PACKAGE_VISIBILITY_FILTERS,
+        PermissionAnnotationDetector.ISSUE_MISSING_PERMISSION_ANNOTATION,
         PermissionMethodDetector.ISSUE_PERMISSION_METHOD_USAGE,
         PermissionMethodDetector.ISSUE_CAN_BE_PERMISSION_METHOD,
     )

tools/lint/framework/checks/src/main/java/com/google/android/lint/PermissionAnnotationDetector.kt

+/*
+ * Copyright (C) 2023 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 com.google.android.lint.aidl
+
+import com.android.tools.lint.detector.api.Category
+import com.android.tools.lint.detector.api.Implementation
+import com.android.tools.lint.detector.api.Issue
+import com.android.tools.lint.detector.api.JavaContext
+import com.android.tools.lint.detector.api.Scope
+import com.android.tools.lint.detector.api.Severity
+import org.jetbrains.uast.UBlockExpression
+import org.jetbrains.uast.UMethod
+
+/**
+ * Ensures all AIDL-generated methods are annotated.
+ *
+ * This detector is run on system_server to validate that any method that may
+ * be exposed via an AIDL interface is permission-annotated. That is, it must
+ * have one of the following annotation:
+ *   - @EnforcePermission
+ *   - @RequiresNoPermission
+ *   - @PermissionManuallyEnforced
+ */
+class PermissionAnnotationDetector : AidlImplementationDetector() {
+
+    override fun visitAidlMethod(
+      context: JavaContext,
+      node: UMethod,
+      interfaceName: String,
+      body: UBlockExpression
+    ) {
+        if (context.evaluator.isAbstract(node)) return
+
+        if (AIDL_PERMISSION_ANNOTATIONS.any { node.hasAnnotation(it) }) return
+
+        context.report(
+            ISSUE_MISSING_PERMISSION_ANNOTATION,
+            node,
+            context.getLocation(node),
+            "The method ${node.name} is not permission-annotated."
+        )
+    }
+
+    companion object {
+
+        private val EXPLANATION_MISSING_PERMISSION_ANNOTATION = """
+          Interfaces that are exposed by system_server are required to have an annotation which
+          denotes the type of permission enforced. There are 3 possible options:
+            - @EnforcePermission
+            - @RequiresNoPermission
+            - @PermissionManuallyEnforced
+          See the documentation of each annotation for further details.
+
+          The annotation on the Java implementation must be the same that the AIDL interface
+          definition. This is verified by a lint in the build system.
+          """.trimIndent()
+
+        @JvmField
+        val ISSUE_MISSING_PERMISSION_ANNOTATION = Issue.create(
+            id = "MissingPermissionAnnotation",
+            briefDescription = "No permission annotation on exposed AIDL interface.",
+            explanation = EXPLANATION_MISSING_PERMISSION_ANNOTATION,
+            category = Category.CORRECTNESS,
+            priority = 5,
+            severity = Severity.ERROR,
+            implementation = Implementation(
+                PermissionAnnotationDetector::class.java,
+                Scope.JAVA_FILE_SCOPE
+            ),
+            enabledByDefault = false
+        )
+    }
+}

tools/lint/framework/checks/src/test/java/com/google/android/lint/PermissionAnnotationDetectorTest.kt

+/*
+ * Copyright (C) 2023 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 com.google.android.lint.aidl
+
+import com.android.tools.lint.checks.infrastructure.LintDetectorTest
+import com.android.tools.lint.checks.infrastructure.TestFile
+import com.android.tools.lint.checks.infrastructure.TestLintTask
+import com.android.tools.lint.detector.api.Detector
+import com.android.tools.lint.detector.api.Issue
+
+@Suppress("UnstableApiUsage")
+class PermissionAnnotationDetectorTest : LintDetectorTest() {
+    override fun getDetector(): Detector = PermissionAnnotationDetector()
+
+    override fun getIssues(): List<Issue> = listOf(
+        PermissionAnnotationDetector.ISSUE_MISSING_PERMISSION_ANNOTATION,
+    )
+
+    override fun lint(): TestLintTask = super.lint().allowMissingSdk(true)
+
+    /** No issue scenario */
+
+    fun testDoesNotDetectIssuesInCorrectScenario() {
+        lint().files(
+            java(
+            """
+            public class Foo extends IFoo.Stub {
+                @Override
+                @android.annotation.EnforcePermission("android.Manifest.permission.READ_CONTACTS")
+                public void testMethod() { }
+            }
+            """
+            ).indented(),
+            *stubs
+        )
+            .run()
+            .expectClean()
+    }
+
+    fun testMissingAnnotation() {
+        lint().files(
+            java(
+            """
+            public class Bar extends IBar.Stub {
+                public void testMethod() { }
+            }
+            """
+            ).indented(),
+            *stubs
+        )
+            .run()
+            .expect(
+                """
+                src/Bar.java:2: Error: The method testMethod is not permission-annotated. [MissingPermissionAnnotation]
+                    public void testMethod() { }
+                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+                1 errors, 0 warnings
+                """
+            )
+    }
+
+    fun testNoIssueWhenExtendingWithAnotherSubclass() {
+        lint().files(
+            java(
+            """
+            public class Foo extends IFoo.Stub {
+                @Override
+                @android.annotation.EnforcePermission(android.Manifest.permission.READ_PHONE_STATE)
+                public void testMethod() { }
+                // not an AIDL method, just another method
+                public void someRandomMethod() { }
+            }
+            """).indented(),
+            java(
+            """
+            public class Baz extends Bar {
+              @Override
+              public void someRandomMethod() { }
+            }
+            """).indented(),
+            *stubs
+        )
+            .run()
+            .expectClean()
+    }
+
+    /* Stubs */
+
+    // A service with permission annotation on the method.
+    private val interfaceIFoo: TestFile = java(
+        """
+        public interface IFoo extends android.os.IInterface {
+         public static abstract class Stub extends android.os.Binder implements IFoo {
+          }
+          @Override
+          @android.annotation.EnforcePermission(android.Manifest.permission.READ_PHONE_STATE)
+          public void testMethod();
+          @Override
+          @android.annotation.RequiresNoPermission
+          public void testMethodNoPermission();
+          @Override
+          @android.annotation.PermissionManuallyEnforced
+          public void testMethodManual();
+        }
+        """
+    ).indented()
+
+    // A service with no permission annotation.
+    private val interfaceIBar: TestFile = java(
+        """
+        public interface IBar extends android.os.IInterface {
+         public static abstract class Stub extends android.os.Binder implements IBar {
+          }
+          public void testMethod();
+        }
+        """
+    ).indented()
+
+    private val stubs = arrayOf(interfaceIFoo, interfaceIBar)
+}