Add ability to sign update.json, needed for autoupdates (#354)

* Add ability to sign update.json, needed for autoupdates

* Remove update from URL

3 files changed, 89 insertions, 18 deletions

diff --git a/src/main/java/io/github/moulberry/notenoughupdates/commands/misc/UpdateCommand.java b/src/main/java/io/github/moulberry/notenoughupdates/commands/misc/UpdateCommand.java
index 36443b27..cac93369 100644
--- a/src/main/java/io/github/moulberry/notenoughupdates/commands/misc/UpdateCommand.java
+++ b/src/main/java/io/github/moulberry/notenoughupdates/commands/misc/UpdateCommand.java
@@ -49,10 +49,6 @@ public class UpdateCommand extends ClientCommandBase {
 			"" +
 				"§e[NEU] §b/neuupdate help - View help.\n" +
 				"§e[NEU] §b/neuupdate check - Check for updates.\n" +
-				"§e[NEU] §b/neuupdate url <url> - Load an update from an direct download URL.\n" +
-				"       §cONLY DO THIS WITH TRUSTED URLS OR IT MIGHT RESULT IN A RAT!\n" +
-				"§e[NEU] §b/neuupdate fromartifact <url> - Load an update from an artifact.\n" +
-				"       §cIf you don't know what this is, don't use it.\n" +
 				""
 		));
 
@@ -68,20 +64,6 @@ public class UpdateCommand extends ClientCommandBase {
 			case "check":
 				neu.autoUpdater.displayUpdateMessageIfOutOfDate();
 				break;
-			case "url":
-				if (args.length != 2) {
-					sender.addChatMessage(new ChatComponentText("§e[NEU] §cPlease provide an URL"));
-				}
-				URL url;
-				try {
-					url = new URL(args[1]);
-				} catch (MalformedURLException e) {
-					e.printStackTrace();
-					sender.addChatMessage(new ChatComponentText("§e[NEU] §cInvalid URL"));
-					return;
-				}
-				neu.autoUpdater.updateFromURL(url);
-				break;
 			case "scheduledownload":
 				neu.autoUpdater.scheduleDownload();
 				break;
diff --git a/src/main/java/io/github/moulberry/notenoughupdates/miscfeatures/updater/AutoUpdater.java b/src/main/java/io/github/moulberry/notenoughupdates/miscfeatures/updater/AutoUpdater.java
index 389cfc75..54fcc204 100644
--- a/src/main/java/io/github/moulberry/notenoughupdates/miscfeatures/updater/AutoUpdater.java
+++ b/src/main/java/io/github/moulberry/notenoughupdates/miscfeatures/updater/AutoUpdater.java
@@ -26,6 +26,7 @@ import com.google.gson.JsonObject;
 import com.google.gson.JsonPrimitive;
 import com.google.gson.JsonSyntaxException;
 import io.github.moulberry.notenoughupdates.NotEnoughUpdates;
+import io.github.moulberry.notenoughupdates.util.MoulSigner;
 import io.github.moulberry.notenoughupdates.util.NotificationHandler;
 import io.github.moulberry.notenoughupdates.util.Utils;
 import net.minecraft.client.Minecraft;
@@ -171,6 +172,14 @@ public class AutoUpdater {
 		File repo = neu.manager.repoLocation;
 		File updateJson = new File(repo, "update.json");
 		if (updateJson.exists()) {
+			if (!MoulSigner.verifySignature(updateJson)) {
+				NotEnoughUpdates.LOGGER.error("update.json found without signature");
+				Minecraft.getMinecraft().thePlayer.addChatMessage(new ChatComponentText(
+					"§e[NEU] §cThere has been an error checking for updates. Check the log or join the discord for more information.").setChatStyle(
+					Utils.createClickStyle(
+						ClickEvent.Action.OPEN_URL, "https://discord.gg/moulberry")));
+				return;
+			}
 			try {
 				JsonObject o = neu.manager.getJsonFromFile(updateJson);
 
diff --git a/src/main/java/io/github/moulberry/notenoughupdates/util/MoulSigner.java b/src/main/java/io/github/moulberry/notenoughupdates/util/MoulSigner.java
new file mode 100644
index 00000000..6510bc20
--- /dev/null
+++ b/src/main/java/io/github/moulberry/notenoughupdates/util/MoulSigner.java
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2022 NotEnoughUpdates contributors
+ *
+ * This file is part of NotEnoughUpdates.
+ *
+ * NotEnoughUpdates is free software: you can redistribute it
+ * and/or modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * NotEnoughUpdates is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with NotEnoughUpdates. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package io.github.moulberry.notenoughupdates.util;
+
+import io.github.moulberry.notenoughupdates.NotEnoughUpdates;
+import org.apache.commons.io.IOUtils;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.security.InvalidKeyException;
+import java.security.KeyFactory;
+import java.security.NoSuchAlgorithmException;
+import java.security.PublicKey;
+import java.security.Signature;
+import java.security.SignatureException;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.X509EncodedKeySpec;
+
+public class MoulSigner {
+	private MoulSigner() {}
+
+	static PublicKey publicKey;
+
+	static {
+		try (InputStream is = MoulSigner.class.getResourceAsStream("/moulberry.key")) {
+			byte[] publicKeyBytes = IOUtils.toByteArray(is);
+			X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(publicKeyBytes);
+			publicKey = KeyFactory.getInstance("RSA").generatePublic(x509EncodedKeySpec);
+		} catch (IOException | NullPointerException | NoSuchAlgorithmException | InvalidKeySpecException e) {
+			NotEnoughUpdates.LOGGER.error("Cannot initialize MoulSigner", e);
+		}
+	}
+
+	public static boolean verifySignature(byte[] data, byte[] signatureBytes) {
+		if (Boolean.getBoolean("neu.noverifysignature")) return true;
+		if (publicKey == null) {
+			NotEnoughUpdates.LOGGER.warn("MoulSigner could not be initialized, will fail this request");
+			return false;
+		}
+		try {
+			Signature signature = Signature.getInstance("SHA256withRSA");
+			signature.initVerify(publicKey);
+			signature.update(data);
+			return signature.verify(signatureBytes);
+		} catch (NoSuchAlgorithmException | InvalidKeyException | SignatureException e) {
+			NotEnoughUpdates.LOGGER.error("Error while verifying signature. Considering this as invalid signature", e);
+			return false;
+		}
+	}
+
+	public static boolean verifySignature(File file) {
+		try {
+			return verifySignature(
+				IOUtils.toByteArray(file.toURI()),
+				IOUtils.toByteArray(new File(file.getParentFile(), file.getName() + ".asc").toURI())
+			);
+		} catch (IOException e) {
+			NotEnoughUpdates.LOGGER.error("Ran into an IOException while verifying a signature", e);
+			return false;
+		}
+	}
+}