feat: encrypt repository credentials at rest

apps/server/src/modules/repositories/repositories.service.ts

@@ -7,12 +7,24 @@ import { db } from "../../db/db";
 import { repositoriesTable } from "../../db/schema";
 import { toMessage } from "../../utils/errors";
 import { restic } from "../../utils/restic";
+import { cryptoUtils } from "../../utils/crypto";
 
 const listRepositories = async () => {
 	const repositories = await db.query.repositoriesTable.findMany({});
 	return repositories;
 };
 
+const encryptConfig = async (config: RepositoryConfig): Promise<RepositoryConfig> => {
+	const encryptedConfig = { ...config };
+	switch (config.backend) {
+		case "s3":
+			encryptedConfig.accessKeyId = await cryptoUtils.encrypt(config.accessKeyId);
+			encryptedConfig.secretAccessKey = await cryptoUtils.encrypt(config.secretAccessKey);
+			break;
+	}
+	return encryptedConfig;
+};
+
 const createRepository = async (name: string, config: RepositoryConfig, compressionMode?: CompressionMode) => {
 	const slug = slugify(name, { lower: true, strict: true });
 
@@ -26,13 +38,15 @@ const createRepository = async (name: string, config: RepositoryConfig, compress
 
 	const id = crypto.randomUUID();
 
+	const encryptedConfig = await encryptConfig(config);
+
 	const [created] = await db
 		.insert(repositoriesTable)
 		.values({
 			id,
 			name: slug,
 			backend: config.backend,
-			config,
+			config: encryptedConfig,
 			compressionMode: compressionMode ?? "auto",
 			status: "unknown",
 		})
@@ -42,7 +56,7 @@ const createRepository = async (name: string, config: RepositoryConfig, compress
 		throw new InternalServerError("Failed to create repository");
 	}
 
-	const { success, error } = await restic.init(config);
+	const { success, error } = await restic.init(encryptedConfig);
 
 	if (success) {
 		await db
@@ -58,14 +72,7 @@ const createRepository = async (name: string, config: RepositoryConfig, compress
 	}
 
 	const errorMessage = toMessage(error);
-	await db
-		.update(repositoriesTable)
-		.set({
-			status: "error",
-			lastError: errorMessage,
-			lastChecked: new Date(),
-		})
-		.where(eq(repositoriesTable.id, id));
+	await db.delete(repositoriesTable).where(eq(repositoriesTable.id, id));
 
 	throw new InternalServerError(`Failed to initialize repository: ${errorMessage}`);
 };

apps/server/src/utils/crypto.ts

@@ -0,0 +1,61 @@
+import crypto from "node:crypto";
+import { RESTIC_PASS_FILE } from "../core/constants";
+
+const algorithm = "aes-256-gcm" as const;
+const keyLength = 32;
+const encryptionPrefix = "encv1";
+
+/**
+ * Given a string, encrypts it using a randomly generated salt
+ */
+const encrypt = async (data: string) => {
+	if (!data) {
+		return data;
+	}
+
+	if (data.startsWith(encryptionPrefix)) {
+		return data;
+	}
+
+	const secret = (await Bun.file(RESTIC_PASS_FILE).text()).trim();
+
+	const salt = crypto.randomBytes(16);
+	const key = crypto.pbkdf2Sync(secret, salt, 100000, keyLength, "sha256");
+	const iv = crypto.randomBytes(12);
+
+	const cipher = crypto.createCipheriv(algorithm, key, iv);
+	const encrypted = Buffer.concat([cipher.update(data), cipher.final()]);
+
+	const tag = cipher.getAuthTag();
+	return `${encryptionPrefix}:${salt.toString("hex")}:${iv.toString("hex")}:${encrypted.toString("hex")}:${tag.toString("hex")}`;
+};
+
+/**
+ * Given an encrypted string, decrypts it using the salt stored in the string
+ */
+const decrypt = async (encryptedData: string) => {
+	const secret = await Bun.file(RESTIC_PASS_FILE).text();
+
+	const parts = encryptedData.split(":").slice(1); // Remove prefix
+	const saltHex = parts.shift() as string;
+	const salt = Buffer.from(saltHex, "hex");
+
+	const key = crypto.pbkdf2Sync(secret, salt, 100000, keyLength, "sha256");
+
+	const iv = Buffer.from(parts.shift() as string, "hex");
+	const encrypted = Buffer.from(parts.shift() as string, "hex");
+	const tag = Buffer.from(parts.shift() as string, "hex");
+	const decipher = crypto.createDecipheriv(algorithm, key, iv);
+
+	decipher.setAuthTag(tag);
+
+	let decrypted = decipher.update(encrypted);
+	decrypted = Buffer.concat([decrypted, decipher.final()]);
+
+	return decrypted.toString();
+};
+
+export const cryptoUtils = {
+	encrypt,
+	decrypt,
+};

apps/server/src/utils/restic.ts

@@ -6,6 +6,7 @@ import { type } from "arktype";
 import { $ } from "bun";
 import { RESTIC_PASS_FILE } from "../core/constants";
 import { logger } from "./logger";
+import { cryptoUtils } from "./crypto";
 
 const backupOutputSchema = type({
 	message_type: "'summary'",
@@ -45,13 +46,13 @@ const buildRepoUrl = (config: RepositoryConfig): string => {
 	}
 };
 
-const buildEnv = (config: RepositoryConfig): Record<string, string> => {
+const buildEnv = async (config: RepositoryConfig) => {
 	const env: Record<string, string> = {};
 
 	switch (config.backend) {
 		case "s3":
-			env.AWS_ACCESS_KEY_ID = config.accessKeyId;
-			env.AWS_SECRET_ACCESS_KEY = config.secretAccessKey;
+			env.AWS_ACCESS_KEY_ID = await cryptoUtils.decrypt(config.accessKeyId);
+			env.AWS_SECRET_ACCESS_KEY = await cryptoUtils.decrypt(config.secretAccessKey);
 			break;
 	}
 
@@ -62,7 +63,7 @@ const init = async (config: RepositoryConfig) => {
 	await ensurePassfile();
 
 	const repoUrl = buildRepoUrl(config);
-	const env = buildEnv(config);
+	const env = await buildEnv(config);
 
 	const res = await $`restic init --repo ${repoUrl} --password-file ${RESTIC_PASS_FILE} --json`.env(env).nothrow();
 
@@ -77,7 +78,7 @@ const init = async (config: RepositoryConfig) => {
 
 const backup = async (config: RepositoryConfig, source: string) => {
 	const repoUrl = buildRepoUrl(config);
-	const env = buildEnv(config);
+	const env = await buildEnv(config);
 
 	const res = await $`restic --repo ${repoUrl} backup ${source} --password-file /data/secrets/restic.pass --json`
 		.env(env)