SteamWar/Paper
13
0
Fork 0
geforkt von Mirrors/Paper
Code Issues Pull-Requests 1 Projekte Releases Wiki Aktivität
2f1f1b7f0c
Paper/patches/server/0714-Deobfuscate-stacktraces-in-log-messages-crash-report.patch

522 Zeilen
23 KiB
Diff
Originalformat Blame Verlauf

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jason Penilla <11360596+jpenilla@users.noreply.github.com>
Date: Sun, 20 Jun 2021 18:19:09 -0700
Subject: [PATCH] Deobfuscate stacktraces in log messages, crash reports, and
etc.
diff --git a/build.gradle.kts b/build.gradle.kts
index 9c1698df7e31c467ddb43c3989a0aeabebb88e94..864f67f57b92bc66208ff632250863484c8ab295 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,8 +1,12 @@
import com.github.jengelman.gradle.plugins.shadow.transformers.Log4j2PluginsCacheFileTransformer
import com.github.jengelman.gradle.plugins.shadow.transformers.Transformer
+import io.papermc.paperweight.tasks.BaseTask
import io.papermc.paperweight.util.Git
+import io.papermc.paperweight.util.defaultOutput
+import io.papermc.paperweight.util.openZip
import io.papermc.paperweight.util.path
import shadow.org.apache.logging.log4j.core.config.plugins.processor.PluginProcessor.PLUGIN_CACHE_FILE
+import java.nio.file.Files
import java.util.Locale
plugins {
@@ -13,6 +17,14 @@ plugins {
repositories {
maven("https://libraries.minecraft.net/")
+ // Paper start
+ maven("https://maven.quiltmc.org/repository/release/") {
+ mavenContent {
+ releasesOnly()
+ includeModule("org.quiltmc", "tiny-mappings-parser")
+ }
+ }
+ // Paper end
}
dependencies {
@@ -49,6 +61,8 @@ dependencies {
implementation("co.aikar:cleaner:1.0-SNAPSHOT") // Paper
implementation("io.netty:netty-all:4.1.65.Final") // Paper
+ implementation("org.quiltmc:tiny-mappings-parser:0.3.0") // Paper - needed to read mappings for stacktrace deobfuscation
+
testImplementation("io.github.classgraph:classgraph:4.8.47") // Paper - mob goal test
testImplementation("junit:junit:4.13.1")
testImplementation("org.hamcrest:hamcrest-library:1.3")
@@ -114,6 +128,44 @@ tasks.shadowJar {
transform(ModifiedLog4j2PluginsCacheFileTransformer::class.java)
}
+// Paper start - include reobf mappings in jar for stacktrace deobfuscation
+abstract class IncludeMappings : BaseTask() {
+ @get:InputFile
+ abstract val inputJar: RegularFileProperty
+
+ @get:InputFile
+ abstract val mappings: RegularFileProperty
+
+ @get:OutputFile
+ abstract val outputJar: RegularFileProperty
+
+ override fun init() {
+ outputJar.convention(defaultOutput())
+ }
+
+ @TaskAction
+ private fun addMappings() {
+ outputJar.get().asFile.parentFile.mkdirs()
+ inputJar.get().asFile.copyTo(outputJar.get().asFile, overwrite = true)
+ outputJar.get().path.openZip().use { fs ->
+ val dir = fs.getPath("META-INF/mappings/")
+ Files.createDirectories(dir)
+ val target = dir.resolve("reobf.tiny")
+ Files.copy(mappings.path, target)
+ }
+ }
+}
+
+val includeMappings = tasks.register<IncludeMappings>("includeMappings") {
+ inputJar.set(tasks.fixJarForReobf.flatMap { it.outputJar })
+ mappings.set(tasks.reobfJar.flatMap { it.mappingsFile })
+}
+
+tasks.reobfJar {
+ inputJar.set(includeMappings.flatMap { it.outputJar })
+}
+// Paper end - include reobf mappings in jar for stacktrace deobfuscation
+
tasks.test {
exclude("org/bukkit/craftbukkit/inventory/ItemStack*Test.class")
}
diff --git a/src/main/java/com/destroystokyo/paper/PaperConfig.java b/src/main/java/com/destroystokyo/paper/PaperConfig.java
index 9f94c4ff06962b7b947c58db93426742574431e3..4f073bff5fa8350e719da648a0c15792dadeef6f 100644
--- a/src/main/java/com/destroystokyo/paper/PaperConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java
@@ -492,6 +492,11 @@ public class PaperConfig {
enableBrigadierConsoleCompletions = getBoolean("settings.console.enable-brigadier-completions", enableBrigadierConsoleCompletions);
}
+ public static boolean deobfuscateStacktraces = true;
+ private static void loggerSettings() {
+ deobfuscateStacktraces = getBoolean("settings.loggers.deobfuscate-stacktraces", deobfuscateStacktraces);
+ }
+
public static int itemValidationDisplayNameLength = 8192;
public static int itemValidationLocNameLength = 8192;
public static int itemValidationLoreLineLength = 8192;
diff --git a/src/main/java/com/destroystokyo/paper/io/SyncLoadFinder.java b/src/main/java/com/destroystokyo/paper/io/SyncLoadFinder.java
index 0bb4aaa546939b67a5d22865190f30478a9337c1..d3e619655382e50e9ac9323ed942502d85c9599c 100644
--- a/src/main/java/com/destroystokyo/paper/io/SyncLoadFinder.java
+++ b/src/main/java/com/destroystokyo/paper/io/SyncLoadFinder.java
@@ -91,7 +91,7 @@ public class SyncLoadFinder {
final JsonArray traces = new JsonArray();
- for (StackTraceElement element : pair.getFirst().stacktrace) {
+ for (StackTraceElement element : io.papermc.paper.util.StacktraceDeobfuscator.INSTANCE.deobfuscateStacktrace(pair.getFirst().stacktrace)) {
traces.add(String.valueOf(element));
}
diff --git a/src/main/java/io/papermc/paper/logging/StacktraceDeobfuscatingRewritePolicy.java b/src/main/java/io/papermc/paper/logging/StacktraceDeobfuscatingRewritePolicy.java
new file mode 100644
index 0000000000000000000000000000000000000000..d019802a36dbaca4bf299a55d28381e43d6b976f
--- /dev/null
+++ b/src/main/java/io/papermc/paper/logging/StacktraceDeobfuscatingRewritePolicy.java
@@ -0,0 +1,31 @@
+package io.papermc.paper.logging;
+
+import io.papermc.paper.util.StacktraceDeobfuscator;
+import org.apache.logging.log4j.core.Core;
+import org.apache.logging.log4j.core.LogEvent;
+import org.apache.logging.log4j.core.appender.rewrite.RewritePolicy;
+import org.apache.logging.log4j.core.config.plugins.Plugin;
+import org.apache.logging.log4j.core.config.plugins.PluginFactory;
+import org.jetbrains.annotations.NotNull;
+
+@Plugin(
+ name = "StacktraceDeobfuscatingRewritePolicy",
+ category = Core.CATEGORY_NAME,
+ elementType = "rewritePolicy",
+ printObject = true
+)
+public final class StacktraceDeobfuscatingRewritePolicy implements RewritePolicy {
+ @Override
+ public @NotNull LogEvent rewrite(final @NotNull LogEvent rewrite) {
+ final Throwable thrown = rewrite.getThrown();
+ if (thrown != null) {
+ StacktraceDeobfuscator.INSTANCE.deobfuscateThrowable(thrown);
+ }
+ return rewrite;
+ }
+
+ @PluginFactory
+ public static @NotNull StacktraceDeobfuscatingRewritePolicy createPolicy() {
+ return new StacktraceDeobfuscatingRewritePolicy();
+ }
+}
diff --git a/src/main/java/io/papermc/paper/util/ObfHelper.java b/src/main/java/io/papermc/paper/util/ObfHelper.java
new file mode 100644
index 0000000000000000000000000000000000000000..271e0a2ec549836a32565bb9100d432cd68d6046
--- /dev/null
+++ b/src/main/java/io/papermc/paper/util/ObfHelper.java
@@ -0,0 +1,87 @@
+package io.papermc.paper.util;
+
+import com.google.common.base.Charsets;
+import com.google.common.collect.ImmutableMap;
+import com.mojang.datafixers.util.Pair;
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.util.Map;
+import net.fabricmc.mapping.tree.ClassDef;
+import net.fabricmc.mapping.tree.MethodDef;
+import net.fabricmc.mapping.tree.TinyMappingFactory;
+import net.fabricmc.mapping.tree.TinyTree;
+import org.checkerframework.checker.nullness.qual.NonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import org.checkerframework.framework.qual.DefaultQualifier;
+
+@DefaultQualifier(NonNull.class)
+public enum ObfHelper {
+ INSTANCE;
+
+ public static final String MOJANG_PLUS_YARN_NAMESPACE = "mojang+yarn";
+ public static final String SPIGOT_NAMESPACE = "spigot";
+
+ private final @Nullable Map<String, ClassMapping> mappings;
+
+ ObfHelper() {
+ this.mappings = loadMappingsIfPresent();
+ }
+
+ public @Nullable Map<String, ClassMapping> mappings() {
+ return this.mappings;
+ }
+
+ private static @Nullable Map<String, ClassMapping> loadMappingsIfPresent() {
+ try (final @Nullable InputStream mappingsInputStream = StacktraceDeobfuscator.class.getClassLoader().getResourceAsStream("META-INF/mappings/reobf.tiny")) {
+ if (mappingsInputStream == null) {
+ return null;
+ }
+ final TinyTree tree = TinyMappingFactory.loadWithDetection(new BufferedReader(new InputStreamReader(mappingsInputStream, Charsets.UTF_8)));
+ final var builder = ImmutableMap.<String, ClassMapping>builder();
+
+ for (final ClassDef classDef : tree.getClasses()) {
+ final String obfClassName = classDef.getName(SPIGOT_NAMESPACE).replace('/', '.');
+ final var methodMappings = ImmutableMap.<Pair<String, String>, MethodMapping>builder();
+
+ for (final MethodDef methodDef : classDef.getMethods()) {
+ final MethodMapping method = new MethodMapping(
+ methodDef.getName(SPIGOT_NAMESPACE),
+ methodDef.getName(MOJANG_PLUS_YARN_NAMESPACE),
+ methodDef.getDescriptor(SPIGOT_NAMESPACE)
+ );
+ methodMappings.put(
+ new Pair<>(method.obfName(), method.descriptor()),
+ method
+ );
+ }
+
+ final ClassMapping map = new ClassMapping(
+ obfClassName,
+ classDef.getName(MOJANG_PLUS_YARN_NAMESPACE).replace('/', '.'),
+ methodMappings.build()
+ );
+ builder.put(map.obfName(), map);
+ }
+
+ return builder.build();
+ } catch (final IOException ex) {
+ System.err.println("Failed to load mappings for stacktrace deobfuscation.");
+ ex.printStackTrace();
+ return null;
+ }
+ }
+
+ public record ClassMapping(
+ String obfName,
+ String mojangName,
+ Map<Pair<String, String>, MethodMapping> methodMappings
+ ) {}
+
+ public record MethodMapping(
+ String obfName,
+ String mojangName,
+ String descriptor
+ ) {}
+}
diff --git a/src/main/java/io/papermc/paper/util/StacktraceDeobfuscator.java b/src/main/java/io/papermc/paper/util/StacktraceDeobfuscator.java
new file mode 100644
index 0000000000000000000000000000000000000000..6ef365dfd3caa0a726983fc57125f4d9a86959fc
--- /dev/null
+++ b/src/main/java/io/papermc/paper/util/StacktraceDeobfuscator.java
@@ -0,0 +1,156 @@
+package io.papermc.paper.util;
+
+import com.destroystokyo.paper.PaperConfig;
+import com.mojang.datafixers.util.Pair;
+import it.unimi.dsi.fastutil.ints.IntArrayList;
+import it.unimi.dsi.fastutil.ints.IntList;
+import java.io.IOException;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import org.checkerframework.checker.nullness.qual.NonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import org.checkerframework.framework.qual.DefaultQualifier;
+import org.objectweb.asm.ClassReader;
+import org.objectweb.asm.ClassVisitor;
+import org.objectweb.asm.Label;
+import org.objectweb.asm.MethodVisitor;
+import org.objectweb.asm.Opcodes;
+
+@DefaultQualifier(NonNull.class)
+public enum StacktraceDeobfuscator {
+ INSTANCE;
+
+ private final Map<Class<?>, Map<Pair<String, String>, IntList>> lineMapCache = Collections.synchronizedMap(new LinkedHashMap<>(128, 0.75f, true) {
+ @Override
+ protected boolean removeEldestEntry(final Map.Entry<Class<?>, Map<Pair<String, String>, IntList>> eldest) {
+ return this.size() > 127;
+ }
+ });
+
+ public void deobfuscateThrowable(final Throwable throwable) {
+ if (!PaperConfig.deobfuscateStacktraces) {
+ return;
+ }
+
+ throwable.setStackTrace(this.deobfuscateStacktrace(throwable.getStackTrace()));
+ final Throwable cause = throwable.getCause();
+ if (cause != null) {
+ this.deobfuscateThrowable(cause);
+ }
+ for (final Throwable suppressed : throwable.getSuppressed()) {
+ this.deobfuscateThrowable(suppressed);
+ }
+ }
+
+ public StackTraceElement[] deobfuscateStacktrace(final StackTraceElement[] traceElements) {
+ if (!PaperConfig.deobfuscateStacktraces) {
+ return traceElements;
+ }
+
+ final @Nullable Map<String, ObfHelper.ClassMapping> mappings = ObfHelper.INSTANCE.mappings();
+ if (mappings == null || traceElements.length == 0) {
+ return traceElements;
+ }
+ final StackTraceElement[] result = new StackTraceElement[traceElements.length];
+ for (int i = 0; i < traceElements.length; i++) {
+ final StackTraceElement element = traceElements[i];
+
+ final String className = element.getClassName();
+ final String methodName = element.getMethodName();
+
+ final ObfHelper.ClassMapping classMapping = mappings.get(className);
+ if (classMapping == null) {
+ result[i] = element;
+ continue;
+ }
+
+ final Class<?> clazz;
+ try {
+ clazz = Class.forName(className);
+ } catch (final ClassNotFoundException ex) {
+ throw new RuntimeException(ex);
+ }
+ final @Nullable Pair<String, String> nameDescriptorPair = this.determineMethodForLine(clazz, element.getLineNumber());
+ final ObfHelper.@Nullable MethodMapping methodMapping = nameDescriptorPair == null
+ ? null
+ : classMapping.methodMappings().get(nameDescriptorPair);
+
+ result[i] = new StackTraceElement(
+ element.getClassLoaderName(),
+ element.getModuleName(),
+ element.getModuleVersion(),
+ classMapping.mojangName(),
+ methodMapping != null ? methodMapping.mojangName() : methodName,
+ sourceFileName(classMapping.mojangName()),
+ element.getLineNumber()
+ );
+ }
+ return result;
+ }
+
+ private @Nullable Pair<String, String> determineMethodForLine(final Class<?> clazz, final int lineNumber) {
+ final Map<Pair<String, String>, IntList> lineMap = this.lineMapCache.computeIfAbsent(clazz, StacktraceDeobfuscator::buildLineMap);
+ for (final var entry : lineMap.entrySet()) {
+ final Pair<String, String> pair = entry.getKey();
+ final IntList lines = entry.getValue();
+ for (int i = 0, linesSize = lines.size(); i < linesSize; i++) {
+ final int num = lines.getInt(i);
+ if (num == lineNumber) {
+ return pair;
+ }
+ }
+ }
+ return null;
+ }
+
+ private static String sourceFileName(final String fullClassName) {
+ final int dot = fullClassName.lastIndexOf('.');
+ final String className = dot == -1
+ ? fullClassName
+ : fullClassName.substring(dot + 1);
+ final String rootClassName = className.split("\\$")[0];
+ return rootClassName + ".java";
+ }
+
+ private static Map<Pair<String, String>, IntList> buildLineMap(final Class<?> key) {
+ final Map<Pair<String, String>, IntList> lineMap = new HashMap<>();
+ final class LineCollectingMethodVisitor extends MethodVisitor {
+ private final IntList lines = new IntArrayList();
+ private final String name;
+ private final String descriptor;
+
+ LineCollectingMethodVisitor(String name, String descriptor) {
+ super(Opcodes.ASM9);
+ this.name = name;
+ this.descriptor = descriptor;
+ }
+
+ @Override
+ public void visitLineNumber(int line, Label start) {
+ super.visitLineNumber(line, start);
+ this.lines.add(line);
+ }
+
+ @Override
+ public void visitEnd() {
+ super.visitEnd();
+ lineMap.put(new Pair<>(this.name, this.descriptor), this.lines);
+ }
+ }
+ final ClassVisitor classVisitor = new ClassVisitor(Opcodes.ASM9) {
+ @Override
+ public MethodVisitor visitMethod(int access, String name, String descriptor, String signature, String[] exceptions) {
+ return new LineCollectingMethodVisitor(name, descriptor);
+ }
+ };
+ try {
+ final ClassReader reader = new ClassReader(key.getName());
+ reader.accept(classVisitor, 0);
+ } catch (final IOException ex) {
+ throw new RuntimeException(ex);
+ }
+ return lineMap;
+ }
+}
diff --git a/src/main/java/io/papermc/paper/util/TraceUtil.java b/src/main/java/io/papermc/paper/util/TraceUtil.java
index 2d5494d2813b773e60ddba6790b750a9a08f21f8..7695bf44503f161523ea612ef8a884ae574a2e21 100644
--- a/src/main/java/io/papermc/paper/util/TraceUtil.java
+++ b/src/main/java/io/papermc/paper/util/TraceUtil.java
@@ -6,13 +6,15 @@ public final class TraceUtil {
public static void dumpTraceForThread(Thread thread, String reason) {
Bukkit.getLogger().warning(thread.getName() + ": " + reason);
- StackTraceElement[] trace = thread.getStackTrace();
+ StackTraceElement[] trace = StacktraceDeobfuscator.INSTANCE.deobfuscateStacktrace(thread.getStackTrace());
for (StackTraceElement traceElement : trace) {
Bukkit.getLogger().warning("\tat " + traceElement);
}
}
public static void dumpTraceForThread(String reason) {
- new Throwable(reason).printStackTrace();
+ final Throwable throwable = new Throwable(reason);
+ StacktraceDeobfuscator.INSTANCE.deobfuscateThrowable(throwable);
+ throwable.printStackTrace();
}
}
diff --git a/src/main/java/net/minecraft/CrashReport.java b/src/main/java/net/minecraft/CrashReport.java
index 62c3c597732e6fb30ed5367d902ea8763507a6b8..b9a618eba86656289e20d051c3f0023ec93bb733 100644
--- a/src/main/java/net/minecraft/CrashReport.java
+++ b/src/main/java/net/minecraft/CrashReport.java
@@ -30,6 +30,7 @@ public class CrashReport {
private final SystemReport systemReport = new SystemReport();
public CrashReport(String message, Throwable cause) {
+ io.papermc.paper.util.StacktraceDeobfuscator.INSTANCE.deobfuscateThrowable(cause); // Paper
this.title = message;
this.exception = cause;
this.systemReport.setDetail("CraftBukkit Information", new org.bukkit.craftbukkit.CraftCrashReport()); // CraftBukkit
diff --git a/src/main/java/net/minecraft/CrashReportCategory.java b/src/main/java/net/minecraft/CrashReportCategory.java
index 3941e14d1c3e6e688e28904948039c8b2200de5f..a4fda4a3bae9ce600e778b44cd3ef432a8b65667 100644
--- a/src/main/java/net/minecraft/CrashReportCategory.java
+++ b/src/main/java/net/minecraft/CrashReportCategory.java
@@ -104,6 +104,7 @@ public class CrashReportCategory {
} else {
this.stackTrace = new StackTraceElement[stackTraceElements.length - 3 - ignoredCallCount];
System.arraycopy(stackTraceElements, 3 + ignoredCallCount, this.stackTrace, 0, this.stackTrace.length);
+ this.stackTrace = io.papermc.paper.util.StacktraceDeobfuscator.INSTANCE.deobfuscateStacktrace(this.stackTrace); // Paper
return this.stackTrace.length;
}
}
diff --git a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
index db0110120f88bc06954fa8c44b2a45f0c8229574..7b6c547e71230fbb3733f99a4597b3f5b51547b8 100644
--- a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
+++ b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
@@ -221,6 +221,7 @@ public class DedicatedServer extends MinecraftServer implements ServerInterface
com.destroystokyo.paper.PaperConfig.registerCommands();
com.destroystokyo.paper.VersionHistoryManager.INSTANCE.getClass(); // load version history now
io.papermc.paper.brigadier.PaperBrigadierProviderImpl.INSTANCE.getClass(); // init PaperBrigadierProvider
+ io.papermc.paper.util.ObfHelper.INSTANCE.getClass(); // load mappings for stacktrace deobf and etc.
// Paper end
this.setPvpAllowed(dedicatedserverproperties.pvp);
diff --git a/src/main/java/org/spigotmc/WatchdogThread.java b/src/main/java/org/spigotmc/WatchdogThread.java
index 4d271cae88c16ed2419f896c728fdff612540500..dcfbe77bdb25d9c58ffb7b75c48bdb580bc0de47 100644
--- a/src/main/java/org/spigotmc/WatchdogThread.java
+++ b/src/main/java/org/spigotmc/WatchdogThread.java
@@ -106,7 +106,7 @@ public class WatchdogThread extends Thread
log.log( Level.SEVERE, "During the run of the server, a plugin set an excessive velocity on an entity" );
log.log( Level.SEVERE, "This may be the cause of the issue, or it may be entirely unrelated" );
log.log( Level.SEVERE, org.bukkit.craftbukkit.CraftServer.excessiveVelEx.getMessage());
- for ( StackTraceElement stack : org.bukkit.craftbukkit.CraftServer.excessiveVelEx.getStackTrace() )
+ for ( StackTraceElement stack : io.papermc.paper.util.StacktraceDeobfuscator.INSTANCE.deobfuscateStacktrace(org.bukkit.craftbukkit.CraftServer.excessiveVelEx.getStackTrace()) ) // Paper
{
log.log( Level.SEVERE, "\t\t" + stack );
}
@@ -194,7 +194,7 @@ public class WatchdogThread extends Thread
}
log.log( Level.SEVERE, "\tStack:" );
//
- for ( StackTraceElement stack : thread.getStackTrace() )
+ for ( StackTraceElement stack : io.papermc.paper.util.StacktraceDeobfuscator.INSTANCE.deobfuscateStacktrace(thread.getStackTrace()) ) // Paper
{
log.log( Level.SEVERE, "\t\t" + stack );
}
diff --git a/src/main/resources/log4j2.xml b/src/main/resources/log4j2.xml
index 67da1aa7a21622fb231d19dede3775a282a4a12e..f91d0df569b2f1d430ea5eee5f53779902a4f32c 100644
--- a/src/main/resources/log4j2.xml
+++ b/src/main/resources/log4j2.xml
@@ -29,15 +29,19 @@
</Policies>
<DefaultRolloverStrategy max="1000"/>
</RollingRandomAccessFile>
+ <Rewrite name="rewrite">
+ <StacktraceDeobfuscatingRewritePolicy />
+ <AppenderRef ref="File"/>
+ <AppenderRef ref="TerminalConsole" level="info"/>
+ <AppenderRef ref="ServerGuiConsole" level="info"/>
+ </Rewrite>
</Appenders>
<Loggers>
<Root level="info">
<filters>
<MarkerFilter marker="NETWORK_PACKETS" onMatch="DENY" onMismatch="NEUTRAL" />
</filters>
- <AppenderRef ref="File"/>
- <AppenderRef ref="TerminalConsole" level="info"/>
- <AppenderRef ref="ServerGuiConsole" level="info"/>
+ <AppenderRef ref="rewrite"/>
</Root>
</Loggers>
</Configuration>
In neuem Issue referenzieren Git Blame ansehen Permalink kopieren