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| 1 | +/* |
| 2 | + * The MIT License |
| 3 | + * |
| 4 | + * Copyright 2022 CloudBees, Inc. |
| 5 | + * |
| 6 | + * Permission is hereby granted, free of charge, to any person obtaining a copy |
| 7 | + * of this software and associated documentation files (the "Software"), to deal |
| 8 | + * in the Software without restriction, including without limitation the rights |
| 9 | + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| 10 | + * copies of the Software, and to permit persons to whom the Software is |
| 11 | + * furnished to do so, subject to the following conditions: |
| 12 | + * |
| 13 | + * The above copyright notice and this permission notice shall be included in |
| 14 | + * all copies or substantial portions of the Software. |
| 15 | + * |
| 16 | + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 17 | + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 18 | + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| 19 | + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 20 | + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 21 | + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| 22 | + * THE SOFTWARE. |
| 23 | + */ |
| 24 | + |
| 25 | +package org.jenkinsci.plugins.workflow.cps; |
| 26 | + |
| 27 | +import edu.umd.cs.findbugs.annotations.CheckForNull; |
| 28 | +import edu.umd.cs.findbugs.annotations.SuppressFBWarnings; |
| 29 | +import hudson.Extension; |
| 30 | +import hudson.ExtensionList; |
| 31 | +import hudson.ExtensionPoint; |
| 32 | +import hudson.Main; |
| 33 | +import java.io.BufferedReader; |
| 34 | +import java.io.IOException; |
| 35 | +import java.io.InputStream; |
| 36 | +import java.io.InputStreamReader; |
| 37 | +import java.net.URL; |
| 38 | +import java.nio.charset.StandardCharsets; |
| 39 | +import java.util.ArrayList; |
| 40 | +import java.util.Arrays; |
| 41 | +import java.util.Collections; |
| 42 | +import java.util.Enumeration; |
| 43 | +import java.util.List; |
| 44 | +import java.util.logging.Level; |
| 45 | +import java.util.logging.Logger; |
| 46 | +import jenkins.util.SystemProperties; |
| 47 | +import org.apache.commons.lang.StringUtils; |
| 48 | + |
| 49 | +/** |
| 50 | + * Determines what Groovy source files can be loaded in Pipelines. |
| 51 | + * |
| 52 | + * In Pipeline, the standard behavior of {@code GroovyClassLoader} would allow Groovy source files from core or plugins |
| 53 | + * to be loaded as long as they are somewhere on the classpath. This includes things like Groovy views, which are not |
| 54 | + * intended to be available to pipelines. When these files are loaded, they are loaded by the trusted |
| 55 | + * {@link CpsGroovyShell} and are not sandbox-transformed, which means that allowing arbitrary Groovy source files to |
| 56 | + * be loaded is potentially unsafe. |
| 57 | + * |
| 58 | + * {@link ClassLoaderImpl} blocks all Groovy source files from being loaded by default unless they are allowed by an |
| 59 | + * implementation of this extension point. |
| 60 | + */ |
| 61 | +public abstract class GroovySourceFileAllowlist implements ExtensionPoint { |
| 62 | + private static final Logger LOGGER = Logger.getLogger(GroovySourceFileAllowlist.class.getName()); |
| 63 | + private static final String DISABLED_PROPERTY = GroovySourceFileAllowlist.class.getName() + ".DISABLED"; |
| 64 | + @SuppressFBWarnings(value = "MS_SHOULD_BE_FINAL", justification = "Non-final for script console access") |
| 65 | + static boolean DISABLED = SystemProperties.getBoolean(DISABLED_PROPERTY); |
| 66 | + |
| 67 | + /** |
| 68 | + * Checks whether a given Groovy source file is allowed to be loaded by {@link CpsFlowExecution#getTrustedShell}. |
| 69 | + * |
| 70 | + * @param groovySourceFileUrl the absolute URL to the Groovy source file as returned by {@link ClassLoader#getResource} |
| 71 | + * @return {@code true} if the Groovy source file may be loaded, {@code false} otherwise |
| 72 | + */ |
| 73 | + public abstract boolean isAllowed(String groovySourceFileUrl); |
| 74 | + |
| 75 | + public static List<GroovySourceFileAllowlist> all() { |
| 76 | + return ExtensionList.lookup(GroovySourceFileAllowlist.class); |
| 77 | + } |
| 78 | + |
| 79 | + /** |
| 80 | + * {@link ClassLoader} that acts normally except for returning {@code null} from {@link #getResource} and |
| 81 | + * {@link #getResources} when looking up Groovy source files if the files are not allowed by |
| 82 | + * {@link GroovySourceFileAllowlist}. |
| 83 | + */ |
| 84 | + static class ClassLoaderImpl extends ClassLoader { |
| 85 | + private static final String LOG_MESSAGE_TEMPLATE = |
| 86 | + "Preventing {0} from being loaded without sandbox protection in {1}. " + |
| 87 | + "To allow access to this file, add any suffix of its URL to the system property ‘" + |
| 88 | + DefaultAllowlist.ALLOWED_SOURCE_FILES_PROPERTY + "’ (use commas to separate multiple files). If you " + |
| 89 | + "want to allow any Groovy file on the Jenkins classpath to be accessed, you may set the system " + |
| 90 | + "property ‘" + DISABLED_PROPERTY + "’ to true."; |
| 91 | + |
| 92 | + private final String owner; |
| 93 | + |
| 94 | + public ClassLoaderImpl(@CheckForNull CpsFlowExecution execution, ClassLoader parent) { |
| 95 | + super(parent); |
| 96 | + this.owner = describeOwner(execution); |
| 97 | + } |
| 98 | + |
| 99 | + private static String describeOwner(@CheckForNull CpsFlowExecution execution) { |
| 100 | + if (execution != null) { |
| 101 | + try { |
| 102 | + return execution.getOwner().getExecutable().toString(); |
| 103 | + } catch (IOException e) { |
| 104 | + // Not significant in this context. |
| 105 | + } |
| 106 | + } |
| 107 | + return "unknown"; |
| 108 | + } |
| 109 | + |
| 110 | + @Override |
| 111 | + public URL getResource(String name) { |
| 112 | + URL url = super.getResource(name); |
| 113 | + if (DISABLED || url == null || !endsWithIgnoreCase(name, ".groovy") || isAllowed(url)) { |
| 114 | + return url; |
| 115 | + } |
| 116 | + // Note: This message gets printed twice because of https://github.com/apache/groovy/blob/41b990d0a20e442f29247f0e04cbed900f3dcad4/src/main/org/codehaus/groovy/control/ClassNodeResolver.java#L184-L186. |
| 117 | + LOGGER.log(Level.WARNING, LOG_MESSAGE_TEMPLATE, new Object[] { url, owner }); |
| 118 | + return null; |
| 119 | + } |
| 120 | + |
| 121 | + @Override |
| 122 | + public Enumeration<URL> getResources(String name) throws IOException { |
| 123 | + Enumeration<URL> urls = super.getResources(name); |
| 124 | + if (DISABLED || !urls.hasMoreElements() || !endsWithIgnoreCase(name, ".groovy")) { |
| 125 | + return urls; |
| 126 | + } |
| 127 | + List<URL> filteredUrls = new ArrayList<>(); |
| 128 | + while (urls.hasMoreElements()) { |
| 129 | + URL url = urls.nextElement(); |
| 130 | + if (isAllowed(url)) { |
| 131 | + filteredUrls.add(url); |
| 132 | + } else { |
| 133 | + LOGGER.log(Level.WARNING, LOG_MESSAGE_TEMPLATE, new Object[] { url, owner }); |
| 134 | + } |
| 135 | + } |
| 136 | + return Collections.enumeration(filteredUrls); |
| 137 | + } |
| 138 | + |
| 139 | + private static boolean isAllowed(URL url) { |
| 140 | + String urlString = url.toString(); |
| 141 | + for (GroovySourceFileAllowlist allowlist : GroovySourceFileAllowlist.all()) { |
| 142 | + if (allowlist.isAllowed(urlString)) { |
| 143 | + return true; |
| 144 | + } |
| 145 | + } |
| 146 | + return false; |
| 147 | + } |
| 148 | + |
| 149 | + private static boolean endsWithIgnoreCase(String value, String suffix) { |
| 150 | + int suffixLength = suffix.length(); |
| 151 | + return value.regionMatches(true, value.length() - suffixLength, suffix, 0, suffixLength); |
| 152 | + } |
| 153 | + } |
| 154 | + |
| 155 | + /** |
| 156 | + * Allows Groovy source files used to implement DSLs in plugins that were created before |
| 157 | + * {@link GroovySourceFileAllowlist} was introduced. |
| 158 | + */ |
| 159 | + @Extension |
| 160 | + public static class DefaultAllowlist extends GroovySourceFileAllowlist { |
| 161 | + private static final Logger LOGGER = Logger.getLogger(DefaultAllowlist.class.getName()); |
| 162 | + private static final String ALLOWED_SOURCE_FILES_PROPERTY = DefaultAllowlist.class.getCanonicalName() + ".ALLOWED_SOURCE_FILES"; |
| 163 | + /** |
| 164 | + * A list containing suffixes of known-good Groovy source file URLs that need to be accessible to Pipeline code. |
| 165 | + */ |
| 166 | + /* Note: Actual ClassLoader resource URLs depend on environmental factors such as webroot settings and whether |
| 167 | + * we are currently testing one of the plugins in the list, so default-allowlist only contains the path |
| 168 | + * component of the resource URLs, and we allow any resource URL that ends with one of the entries in the list. |
| 169 | + * |
| 170 | + * We could try to load the exact URLs at runtime, but then we would have to account for dynamic plugin loading |
| 171 | + * (especially when a new Jenkins controller is initialized) and the fact that workflow-cps is always a |
| 172 | + * dependency of these plugins. |
| 173 | + */ |
| 174 | + static final List<String> ALLOWED_SOURCE_FILES = new ArrayList<>(); |
| 175 | + |
| 176 | + public DefaultAllowlist() throws IOException { |
| 177 | + // We load custom entries first to improve performance in case .groovy is used for the property. |
| 178 | + String propertyValue = SystemProperties.getString(ALLOWED_SOURCE_FILES_PROPERTY, ""); |
| 179 | + for (String groovyFile : propertyValue.split(",")) { |
| 180 | + groovyFile = StringUtils.trimToNull(groovyFile); |
| 181 | + if (groovyFile != null) { |
| 182 | + if (groovyFile.endsWith(".groovy")) { |
| 183 | + ALLOWED_SOURCE_FILES.add(groovyFile); |
| 184 | + LOGGER.log(Level.INFO, "Allowing Pipelines to access {0}", groovyFile); |
| 185 | + } else { |
| 186 | + LOGGER.log(Level.WARNING, "Ignoring invalid Groovy source file: {0}", groovyFile); |
| 187 | + } |
| 188 | + } |
| 189 | + } |
| 190 | + loadDefaultAllowlist(ALLOWED_SOURCE_FILES); |
| 191 | + // Some plugins use test-specific Groovy DSLs. |
| 192 | + if (Main.isUnitTest) { |
| 193 | + ALLOWED_SOURCE_FILES.addAll(Arrays.asList( |
| 194 | + // pipeline-model-definition |
| 195 | + "/org/jenkinsci/plugins/pipeline/modeldefinition/agent/impl/LabelAndOtherFieldAgentScript.groovy", |
| 196 | + "/org/jenkinsci/plugins/pipeline/modeldefinition/parser/GlobalStageNameTestConditionalScript.groovy" |
| 197 | + )); |
| 198 | + } |
| 199 | + } |
| 200 | + |
| 201 | + private static void loadDefaultAllowlist(List<String> allowlist) throws IOException { |
| 202 | + try (InputStream is = GroovySourceFileAllowlist.class.getResourceAsStream("GroovySourceFileAllowlist/default-allowlist"); |
| 203 | + BufferedReader reader = new BufferedReader(new InputStreamReader(is, StandardCharsets.UTF_8));) { |
| 204 | + String line; |
| 205 | + while ((line = reader.readLine()) != null) { |
| 206 | + line = line.trim(); |
| 207 | + if (!line.isEmpty() && !line.startsWith("#")) { |
| 208 | + allowlist.add(line); |
| 209 | + } |
| 210 | + } |
| 211 | + } |
| 212 | + } |
| 213 | + |
| 214 | + @Override |
| 215 | + public boolean isAllowed(String groovySourceFileUrl) { |
| 216 | + for (String sourceFile : ALLOWED_SOURCE_FILES) { |
| 217 | + if (groovySourceFileUrl.endsWith(sourceFile)) { |
| 218 | + return true; |
| 219 | + } |
| 220 | + } |
| 221 | + return false; |
| 222 | + } |
| 223 | + } |
| 224 | + |
| 225 | +} |
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