Allow sanitizing the command input

build.gradle

@@ -56,6 +56,8 @@ dependencies {
     // todo once we fix the logging properties set this to compile
     testCompile group: 'org.slf4j', name: 'slf4j-log4j12', version: '1.7.25'
 
+    implementation 'com.github.I-Al-Istannen:JvmAgentUtils:de8d42398b'
+
     testImplementation group: 'org.junit.jupiter', name: 'junit-jupiter-api', version: junitVersion
     testRuntimeOnly group: 'org.junit.jupiter', name: 'junit-jupiter-engine', version: junitVersion
 }

src/main/java/org/togetherjava/discord/server/EventHandler.java

@@ -5,6 +5,7 @@
 import jdk.jshell.SnippetEvent;
 import org.togetherjava.discord.server.execution.JShellSessionManager;
 import org.togetherjava.discord.server.execution.JShellWrapper;
+import org.togetherjava.discord.server.io.input.InputSanitizerManager;
 import org.togetherjava.discord.server.rendering.RendererManager;
 import sx.blah.discord.api.events.EventSubscriber;
 import sx.blah.discord.handle.impl.events.guild.channel.message.MessageReceivedEvent;
@@ -22,12 +23,14 @@ public class EventHandler {
     private JShellSessionManager jShellSessionManager;
     private final String botPrefix;
     private RendererManager rendererManager;
+    private InputSanitizerManager sanitizerManager;
 
     @SuppressWarnings("WeakerAccess")
     public EventHandler(Config config) {
         this.jShellSessionManager = new JShellSessionManager(config);
         this.botPrefix = config.getString("prefix");
         this.rendererManager = new RendererManager();
+        this.sanitizerManager = new InputSanitizerManager();
     }
 
     @EventSubscriber
@@ -51,7 +54,7 @@ private String parseCommandFromMessage(String messageContent) {
             return codeBlockMatcher.group(2);
         }
 
-        return withoutPrefix;
+        return sanitizerManager.sanitize(withoutPrefix);
     }
 
     private void executeCommand(IUser user, JShellWrapper shell, String command, IChannel channel) {

src/main/java/org/togetherjava/discord/server/JShellBot.java

@@ -25,7 +25,6 @@ public static void main(String[] args) {
     }
 
     /**
-     *
      * @throws Exception
      */
     public void start() throws Exception {
@@ -37,21 +36,19 @@ public void start() throws Exception {
         Path botConfigPath = botConfigPathString == null ? null
                 : Paths.get(botConfigPathString);
 
-        if(botConfigPath == null){
+        if (botConfigPath == null) {
             Properties prop = new Properties();
             prop.load(JShellBot.class.getResourceAsStream("/bot.properties"));
             config = new Config(prop);
-        }
-        else{
+        } else {
             config = new Config(botConfigPath);
         }
 
-        if(config.getString("token") != null){
+        if (config.getString("token") != null) {
             IDiscordClient client = BotUtils.buildDiscordClient(config.getString("token"));
             client.getDispatcher().registerListener(new EventHandler(config));
             client.login();
-        }
-        else{
+        } else {
             log.error("Token not set or config file not found in");
             exit(1);
         }

src/main/java/org/togetherjava/discord/server/JshellSecurityManager.java

@@ -0,0 +1,26 @@
+package org.togetherjava.discord.server;
+
+import java.security.Permission;
+import java.util.Arrays;
+
+public class JshellSecurityManager extends SecurityManager {
+
+    @Override
+    public void checkPermission(Permission perm) {
+        // allow all but Jshell to bypass this
+        if (!comesFromMe() && comesFromJshell()) {
+            super.checkPermission(perm);
+        }
+    }
+
+    private boolean comesFromJshell() {
+        return Arrays.stream(getClassContext())
+                .anyMatch(aClass -> aClass.getName().contains("REPL"));
+    }
+
+    private boolean comesFromMe() {
+        return Arrays.stream(getClassContext())
+                .skip(2)
+                .anyMatch(aClass -> aClass == getClassContext()[0]);
+    }
+}

src/main/java/org/togetherjava/discord/server/execution/JShellWrapper.java

@@ -9,6 +9,7 @@
 import org.apache.logging.log4j.Logger;
 import org.togetherjava.discord.server.Config;
 import org.togetherjava.discord.server.io.StringOutputStream;
+import org.togetherjava.discord.server.sandbox.AgentAttacher;
 import org.togetherjava.discord.server.sandbox.FilteredExecutionControlProvider;
 import org.togetherjava.discord.server.sandbox.Sandbox;
 
@@ -43,6 +44,11 @@ private JShell buildJShell(OutputStream outputStream, Config config) {
             return JShell.builder()
                     .out(out)
                     .err(out)
+                    .remoteVMOptions(
+                            AgentAttacher.getCommandLineArgument(),
+                            "-Djava.security.policy=="
+                                    + getClass().getResource("/jshell.policy").toExternalForm()
+                    )
                     .executionEngine(getExecutionControlProvider(config), Map.of())
                     .build();
         } catch (UnsupportedEncodingException e) {

src/main/java/org/togetherjava/discord/server/io/input/InputSanitizer.java

@@ -0,0 +1,12 @@
+package org.togetherjava.discord.server.io.input;
+
+public interface InputSanitizer {
+
+    /**
+     * Sanizizes the input to Jshell so that errors in it might be accounted for.
+     *
+     * @param input the input to sanitize
+     * @return the resulting input
+     */
+    String sanitize(String input);
+}

src/main/java/org/togetherjava/discord/server/io/input/InputSanitizerManager.java

@@ -0,0 +1,42 @@
+package org.togetherjava.discord.server.io.input;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class InputSanitizerManager {
+
+    private List<InputSanitizer> sanitizers;
+
+    public InputSanitizerManager() {
+        this.sanitizers = new ArrayList<>();
+
+        addDefaults();
+    }
+
+    private void addDefaults() {
+        addSanitizer(new UnicodeQuoteSanitizer());
+    }
+
+    /**
+     * Adds a new {@link InputSanitizer}
+     *
+     * @param sanitizer the sanitizer to add
+     */
+    public void addSanitizer(InputSanitizer sanitizer) {
+        sanitizers.add(sanitizer);
+    }
+
+    /**
+     * Sanitizes a given input using all registered {@link InputSanitizer}s.
+     *
+     * @param input the input to sanitize
+     * @return the resulting input
+     */
+    public String sanitize(String input) {
+        String result = input;
+        for (InputSanitizer sanitizer : sanitizers) {
+            result = sanitizer.sanitize(input);
+        }
+        return result;
+    }
+}

src/main/java/org/togetherjava/discord/server/io/input/UnicodeQuoteSanitizer.java

@@ -0,0 +1,11 @@
+package org.togetherjava.discord.server.io.input;
+
+public class UnicodeQuoteSanitizer implements InputSanitizer {
+
+    @Override
+    public String sanitize(String input) {
+        return input
+                .replace("“", "\"")
+                .replace("”", "\"");
+    }
+}

src/main/java/org/togetherjava/discord/server/rendering/CompilationErrorRenderer.java

@@ -13,8 +13,6 @@ public boolean isApplicable(Object param) {
 
     @Override
     public EmbedBuilder render(Object object, EmbedBuilder builder) {
-        RenderUtils.applyFailColor(builder);
-
         Diag diag = (Diag) object;
         return builder
                 .appendField("Is compilation error", String.valueOf(diag.isError()), true)

src/main/java/org/togetherjava/discord/server/rendering/ExceptionRenderer.java

@@ -12,8 +12,6 @@ public boolean isApplicable(Object param) {
 
     @Override
     public EmbedBuilder render(Object object, EmbedBuilder builder) {
-        RenderUtils.applyFailColor(builder);
-
         Throwable throwable = (Throwable) object;
         builder
                 .appendField("Exception type", throwable.getClass().getSimpleName(), true)

src/main/java/org/togetherjava/discord/server/rendering/RejectedColorRenderer.java

@@ -0,0 +1,23 @@
+package org.togetherjava.discord.server.rendering;
+
+import jdk.jshell.Snippet;
+import org.togetherjava.discord.server.execution.JShellWrapper;
+import sx.blah.discord.util.EmbedBuilder;
+
+public class RejectedColorRenderer implements Renderer {
+    @Override
+    public boolean isApplicable(Object param) {
+        return param instanceof JShellWrapper.JShellResult;
+    }
+
+    @Override
+    public EmbedBuilder render(Object object, EmbedBuilder builder) {
+        JShellWrapper.JShellResult result = (JShellWrapper.JShellResult) object;
+
+        if (result.getEvents().stream().anyMatch(e -> e.status() == Snippet.Status.REJECTED)) {
+            RenderUtils.applyFailColor(builder);
+        }
+
+        return builder;
+    }
+}

src/main/java/org/togetherjava/discord/server/rendering/RendererManager.java

@@ -19,6 +19,7 @@ public RendererManager() {
         addRenderer(new ExceptionRenderer());
         addRenderer(new StandardOutputRenderer());
         addRenderer(new CompilationErrorRenderer());
+        addRenderer(new RejectedColorRenderer());
     }
 
     /**

src/main/java/org/togetherjava/discord/server/sandbox/AgentAttacher.java

@@ -0,0 +1,22 @@
+package org.togetherjava.discord.server.sandbox;
+
+import me.ialistannen.jvmagentutils.instrumentation.JvmUtils;
+import org.togetherjava.discord.server.JshellSecurityManager;
+
+import java.nio.file.Path;
+
+public class AgentAttacher {
+
+    private static final Path agentJar = JvmUtils.generateAgentJar(
+            AgentMain.class, AgentMain.class, JshellSecurityManager.class
+    );
+
+    /**
+     * Returns the command line argument that attaches the agent.
+     *
+     * @return the command line argument to start it
+     */
+    public static String getCommandLineArgument() {
+        return "-javaagent:" + agentJar.toAbsolutePath();
+    }
+}

src/main/java/org/togetherjava/discord/server/sandbox/AgentMain.java

@@ -0,0 +1,16 @@
+package org.togetherjava.discord.server.sandbox;
+
+import org.togetherjava.discord.server.JshellSecurityManager;
+
+import java.lang.instrument.ClassFileTransformer;
+import java.lang.instrument.Instrumentation;
+
+/**
+ * An agent that sets the security manager JShell uses.
+ */
+public class AgentMain implements ClassFileTransformer {
+
+    public static void premain(String args, Instrumentation inst) {
+        System.setSecurityManager(new JshellSecurityManager());
+    }
+}

src/main/java/org/togetherjava/discord/server/sandbox/Sandbox.java

@@ -1,6 +1,9 @@
 package org.togetherjava.discord.server.sandbox;
 
-import java.security.*;
+import java.security.AccessControlContext;
+import java.security.PermissionCollection;
+import java.security.Permissions;
+import java.security.ProtectionDomain;
 import java.util.function.Supplier;
 
 public class Sandbox {
@@ -27,9 +30,10 @@ public Sandbox() {
      * @return the result of running it
      */
     public <T> T runInSandBox(Supplier<T> supplier) {
-        return AccessController.doPrivileged(
-                (PrivilegedAction<T>) supplier::get,
-                controlContext
-        );
+        return supplier.get();
+//        return AccessController.doPrivileged(
+//                (PrivilegedAction<T>) supplier::get,
+//                controlContext
+//        );
     }
 }

src/main/resources/jshell.policy

@@ -0,0 +1,5 @@
+// Restrict what Jshell can run
+grant {
+            permission java.util.RuntimePermission "accessDeclaredMembers";
+            permission java.util.RuntimePermission "accessClassInPackage";
+};