Implement use of a Maven Central mirror for dependency downloads

People keep telling me that LP's use of Maven Central for downloading dependencies is not allowed / inappropriate / abusive. I disagree but I'm bored of hearing it. Using a mirror will mean that all of the load is taken off of Central, and is instead absorbed by my servers + (mostly) Cloudflare.

- The mirror is (currently) hosted at https://nexus.lucko.me/repository/maven-central/
- The prospect of the mirror becoming compromised is not a concern. LuckPerms compares the downloaded content against a checksum before saving it.
- The prospect of the mirror going offline is also not a concern. We will fallback to Maven Central if a connection cannot be made to the mirror.
This commit is contained in:
Luck 2019-01-07 16:56:16 +00:00
parent 048768007d
commit 9b1c73ed23
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2 changed files with 97 additions and 50 deletions

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@ -32,8 +32,11 @@ import me.lucko.luckperms.common.dependencies.relocation.Relocation;
import me.lucko.luckperms.common.dependencies.relocation.RelocationHelper;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.security.MessageDigest;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Base64;
import java.util.List;
@ -265,12 +268,14 @@ public enum Dependency {
Relocation.of("toml4j", "com{}moandjiezana{}toml")
);
private final String url;
private final List<URL> urls;
private final String version;
private final byte[] checksum;
private final List<Relocation> relocations;
private static final String MAVEN_CENTRAL_FORMAT = "https://repo1.maven.org/maven2/%s/%s/%s/%s-%s.jar";
private static final String MAVEN_CENTRAL_REPO = "https://repo1.maven.org/maven2/";
private static final String LUCK_MIRROR_REPO = "https://nexus.lucko.me/repository/maven-central/";
private static final String MAVEN_FORMAT = "%s/%s/%s/%s-%s.jar";
Dependency(String groupId, String artifactId, String version, String checksum) {
this(groupId, artifactId, version, checksum, ImmutableList.of());
@ -281,20 +286,21 @@ public enum Dependency {
}
Dependency(String groupId, String artifactId, String version, String checksum, List<Relocation> relocations) {
this(
String.format(MAVEN_CENTRAL_FORMAT,
rewriteEscaping(groupId).replace(".", "/"),
rewriteEscaping(artifactId),
version,
rewriteEscaping(artifactId),
version
),
version, checksum, relocations
String path = String.format(MAVEN_FORMAT,
rewriteEscaping(groupId).replace(".", "/"),
rewriteEscaping(artifactId),
version,
rewriteEscaping(artifactId),
version
);
}
Dependency(String url, String version, String checksum, List<Relocation> relocations) {
this.url = url;
try {
this.urls = ImmutableList.of(
new URL(LUCK_MIRROR_REPO + path),
new URL(MAVEN_CENTRAL_REPO + path)
);
} catch (MalformedURLException e) {
throw new RuntimeException(e); // propagate
}
this.version = version;
this.checksum = Base64.getDecoder().decode(checksum);
this.relocations = ImmutableList.copyOf(relocations);
@ -308,26 +314,32 @@ public enum Dependency {
MessageDigest digest = MessageDigest.getInstance("SHA-256");
for (Dependency dependency : values()) {
URL url = new URL(dependency.getUrl());
try (InputStream in = url.openStream()) {
byte[] bytes = ByteStreams.toByteArray(in);
if (bytes.length == 0) {
throw new RuntimeException("Empty stream");
List<byte[]> hashes = new ArrayList<>();
for (URL url : dependency.getUrls()) {
URLConnection connection = url.openConnection();
connection.setRequestProperty("User-Agent", "luckperms");
try (InputStream in = connection.getInputStream()) {
byte[] bytes = ByteStreams.toByteArray(in);
if (bytes.length == 0) {
throw new RuntimeException("Empty stream");
}
hashes.add(digest.digest(bytes));
}
}
byte[] hash = digest.digest(bytes);
if (Arrays.equals(hash, dependency.getChecksum())) {
System.out.println("MATCH " + dependency.name() + ": " + Base64.getEncoder().encodeToString(hash));
} else {
System.out.println("NO MATCH " + dependency.name() + ": " + Base64.getEncoder().encodeToString(hash));
for (int i = 0; i < hashes.size(); i++) {
byte[] hash = hashes.get(i);
if (!Arrays.equals(hash, dependency.getChecksum())) {
System.out.println("NO MATCH - REPO " + i + " - " + dependency.name() + ": " + Base64.getEncoder().encodeToString(hash));
}
}
}
}
public String getUrl() {
return this.url;
public List<URL> getUrls() {
return this.urls;
}
public String getVersion() {

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@ -39,6 +39,7 @@ import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.nio.file.Files;
import java.nio.file.Path;
import java.security.MessageDigest;
@ -51,6 +52,7 @@ import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.TimeUnit;
/**
* Responsible for loading runtime dependencies.
@ -209,35 +211,68 @@ public class DependencyManager {
return file;
}
URL url = new URL(dependency.getUrl());
try (InputStream in = url.openStream()) {
boolean success = false;
Exception lastError = null;
// download the jar content
byte[] bytes = ByteStreams.toByteArray(in);
if (bytes.length == 0) {
throw new RuntimeException("Empty stream");
// getUrls returns two possible sources of the dependency.
// [0] is a mirror of Maven Central, used to reduce load on central. apparently they don't like being used as a CDN
// [1] is Maven Central itself
// side note: the relative "security" of the mirror is less than central, but it actually doesn't matter.
// we compare the downloaded file against a checksum here, so even if the mirror became compromised, RCE wouldn't be possible.
// if the mirror download doesn't match the checksum, we just try maven central instead.
List<URL> urls = dependency.getUrls();
for (int i = 0; i < urls.size() && !success; i++) {
URL url = urls.get(i);
try {
URLConnection connection = url.openConnection();
// i == 0 when we're trying to use the mirror repo.
// set some timeout properties so when/if this repository goes offline, we quickly fallback to central.
if (i == 0) {
connection.setRequestProperty("User-Agent", "luckperms");
connection.setConnectTimeout((int) TimeUnit.SECONDS.toMillis(5));
connection.setReadTimeout((int) TimeUnit.SECONDS.toMillis(10));
}
try (InputStream in = connection.getInputStream()) {
// download the jar content
byte[] bytes = ByteStreams.toByteArray(in);
if (bytes.length == 0) {
throw new RuntimeException("Empty stream");
}
// compute a hash for the downloaded file
byte[] hash = this.digest.digest(bytes);
// ensure the hash matches the expected checksum
if (!Arrays.equals(hash, dependency.getChecksum())) {
throw new RuntimeException("Downloaded file had an invalid hash. " +
"Expected: " + Base64.getEncoder().encodeToString(dependency.getChecksum()) + " " +
"Actual: " + Base64.getEncoder().encodeToString(hash));
}
this.plugin.getLogger().info("Successfully downloaded '" + fileName + "' with matching checksum: " + Base64.getEncoder().encodeToString(hash));
// if the checksum matches, save the content to disk
Files.write(file, bytes);
success = true;
}
} catch (Exception e) {
lastError = e;
}
}
// compute a hash for the downloaded file
byte[] hash = this.digest.digest(bytes);
// ensure the hash matches the expected checksum
if (!Arrays.equals(hash, dependency.getChecksum())) {
throw new RuntimeException("Downloaded file had an invalid hash. " +
"Expected: " + Base64.getEncoder().encodeToString(dependency.getChecksum()) + " " +
"Actual: " + Base64.getEncoder().encodeToString(hash));
}
this.plugin.getLogger().info("Successfully downloaded '" + fileName + "' with matching checksum: " + Base64.getEncoder().encodeToString(hash));
// if the checksum matches, save the content to disk
Files.write(file, bytes);
if (!success) {
throw new RuntimeException("Unable to download", lastError);
}
// ensure the file saved correctly
if (!Files.exists(file)) {
throw new IllegalStateException("File not present. - " + file.toString());
throw new IllegalStateException("File not present: " + file.toString());
} else {
return file;
}