fix(core): Repair data-encryption keys stored as the raw instance key (backport to release-candidate/2.39.x) (#38911)

Co-authored-by: Andreas Fitzek <andreas.fitzek@n8n.io>

packages/cli/src/encryption/__tests__/key-manager.service.test.ts

@@ -694,13 +694,14 @@ describe('KeyManagerService', () => {
 		const makeRepairService = (encryptionKey = randomBytes(24).toString('base64')) => {
 			const repo = mock<DeploymentKeyRepository>();
 			const cipher = realCipher(encryptionKey);
+			const logger = mock<Logger>();
 			const service = new KeyManagerService(
 				repo,
 				cipher,
 				mock<InstanceSettings>({ encryptionKey }),
-				mock<Logger>(),
+				logger,
 			);
-			return { service, repo, cipher };
+			return { service, repo, cipher, logger };
 		};
 
 		// A real, freshly generated DEK — never a hand-built constant.
@@ -721,6 +722,18 @@ describe('KeyManagerService', () => {
 			expect(cipher.decryptDEKWithInstanceKey(wrapped)).toBe(rawKey);
 		});
 
+		it('recovers a raw instance key stored verbatim and re-wraps it as GCM', async () => {
+			const encryptionKey = randomBytes(24).toString('base64');
+			const { service, repo, cipher } = makeRepairService(encryptionKey);
+			repo.findDataEncryptionKeys.mockResolvedValue([makeKey({ id: 'k', value: encryptionKey })]);
+
+			await service.repairLegacyDataEncryptionKeys();
+
+			const [id, , wrapped] = repo.rewrapLegacyDataEncryptionValue.mock.calls[0];
+			expect(id).toBe('k');
+			expect(cipher.decryptDEKWithInstanceKey(wrapped)).toBe(encryptionKey);
+		});
+
 		it.each<[string, (cipher: Cipher, other: Cipher) => string]>([
 			['already GCM-wrapped', (cipher) => cipher.encryptDEKWithInstanceKey(rawKey)],
 			[
@@ -740,6 +753,32 @@ describe('KeyManagerService', () => {
 			expect(repo.rewrapLegacyDataEncryptionValue).not.toHaveBeenCalled();
 		});
 
+		it('warns about an unrecognized value it cannot re-wrap', async () => {
+			const { service, repo, logger } = makeRepairService();
+			repo.findDataEncryptionKeys.mockResolvedValue([
+				makeKey({ id: 'k', value: randomBytes(48).toString('base64') }),
+			]);
+
+			await service.repairLegacyDataEncryptionKeys();
+
+			expect(repo.rewrapLegacyDataEncryptionValue).not.toHaveBeenCalled();
+			expect(logger.warn).toHaveBeenCalledWith(expect.stringContaining('unrecognized format'), {
+				error: expect.any(Error),
+			});
+		});
+
+		it('does not warn about an already GCM-wrapped value', async () => {
+			const { service, repo, cipher, logger } = makeRepairService();
+			repo.findDataEncryptionKeys.mockResolvedValue([
+				makeKey({ id: 'k', value: cipher.encryptDEKWithInstanceKey(rawKey) }),
+			]);
+
+			await service.repairLegacyDataEncryptionKeys();
+
+			expect(repo.rewrapLegacyDataEncryptionValue).not.toHaveBeenCalled();
+			expect(logger.warn).not.toHaveBeenCalled();
+		});
+
 		it('is a no-op when there are no data-encryption keys', async () => {
 			const { service, repo } = makeRepairService();
 			repo.findDataEncryptionKeys.mockResolvedValue([]);

packages/cli/src/encryption/key-manager.service.ts

@@ -134,6 +134,12 @@ export class KeyManagerService implements IEncryptionKeyProvider {
 	 */
 	private recoverLegacyDek(keyInfo: DeploymentKey): string | null {
 		const { value } = keyInfo;
+		// Older seed: the DEK stored as the instance key verbatim, unwrapped. Checked
+		// first so a value equal to the instance key is recovered whatever its shape.
+		if (value === this.instanceSettings.encryptionKey) {
+			return value;
+		}
+
 		// 2.18.x: raw key material, used directly. Re-wrap as-is, no decrypt needed.
 		if (RAW_DEK_PATTERN.test(value)) {
 			return value;
@@ -159,7 +165,17 @@ export class KeyManagerService implements IEncryptionKeyProvider {
 			return recovered;
 		}
 
-		// Already GCM-wrapped or an unknown format: leave untouched.
+		// A value that already unwraps is current-format and needs no repair. Warn
+		// about anything else. A silent skip leaves every no-prefix read failing
+		// with a message that blames the instance key.
+		try {
+			this.cipher.decryptDEKWithInstanceKey(value);
+		} catch (error) {
+			this.logger.warn(
+				`DEK ${keyInfo.id} is in an unrecognized format. n8n cannot re-wrap it with this instance key, so reads of data without a key-id prefix will fail.`,
+				{ error },
+			);
+		}
 		return null;
 	}