lint/libs/lint-checks/src/main/java/com/android/tools/lint/checks/SignatureOrSystemDetector.java

/*
 * Copyright (C) 2014 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.android.tools.lint.checks;

import static com.android.tools.lint.checks.PermissionRequirement.ATTR_PROTECTION_LEVEL;

import com.android.annotations.NonNull;
import com.android.tools.lint.detector.api.Category;
import com.android.tools.lint.detector.api.Detector;
import com.android.tools.lint.detector.api.Implementation;
import com.android.tools.lint.detector.api.Issue;
import com.android.tools.lint.detector.api.LintFix;
import com.android.tools.lint.detector.api.Scope;
import com.android.tools.lint.detector.api.Severity;
import com.android.tools.lint.detector.api.XmlContext;
import com.android.tools.lint.detector.api.XmlScanner;
import java.util.Collection;
import java.util.Collections;
import org.w3c.dom.Attr;

/** Checks if signatureOrSystem level permissions are set. */
public class SignatureOrSystemDetector extends Detector implements XmlScanner {
    public static final Issue ISSUE =
            Issue.create(
                    "SignatureOrSystemPermissions",
                    "Declaring signatureOrSystem permissions",
                    "The `signature` protection level should probably be sufficient for most needs and "
                            + "works regardless of where applications are installed. The "
                            + "`signatureOrSystem` level is used for certain situations where "
                            + "multiple vendors have applications built into a system image and "
                            + "need to share specific features explicitly because they are being built "
                            + "together.",
                    Category.SECURITY,
                    5,
                    Severity.WARNING,
                    new Implementation(SignatureOrSystemDetector.class, Scope.MANIFEST_SCOPE));
    private static final String SIGNATURE_OR_SYSTEM = "signatureOrSystem";

    // ---- Implements XmlScanner ----

    @Override
    public Collection<String> getApplicableAttributes() {
        return Collections.singletonList(ATTR_PROTECTION_LEVEL);
    }

    @Override
    public void visitAttribute(@NonNull XmlContext context, @NonNull Attr attribute) {
        String protectionLevel = attribute.getValue();
        if (protectionLevel != null && protectionLevel.equals(SIGNATURE_OR_SYSTEM)) {
            String message = "`protectionLevel` should probably not be set to `signatureOrSystem`";
            LintFix fix = fix().replace().text("signatureOrSystem").with("signature").build();
            context.report(ISSUE, attribute, context.getLocation(attribute), message, fix);
        }
    }
}