From 9c965185de7908bdde1776369453cce384f9e82c Mon Sep 17 00:00:00 2001
From: Timo Glastra <timo@animo.id>
Date: Thu, 20 Jan 2022 22:29:04 +0100
Subject: [PATCH] fix: verify jws contains at least 1 signature (#600)

---
 packages/core/src/crypto/JwsService.ts               |  4 ++++
 .../core/src/crypto/__tests__/JwsService.test.ts     | 12 +++++++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/packages/core/src/crypto/JwsService.ts b/packages/core/src/crypto/JwsService.ts
index 04c08a3669..ded316b90a 100644
--- a/packages/core/src/crypto/JwsService.ts
+++ b/packages/core/src/crypto/JwsService.ts
@@ -44,6 +44,10 @@ export class JwsService {
     const base64Payload = BufferEncoder.toBase64URL(payload)
     const signatures = 'signatures' in jws ? jws.signatures : [jws]
 
+    if (signatures.length === 0) {
+      throw new AriesFrameworkError('Unable to verify JWS: No entries in JWS signatures array.')
+    }
+
     const signerVerkeys = []
     for (const jws of signatures) {
       const protectedJson = JsonEncoder.fromBase64(jws.protected)
diff --git a/packages/core/src/crypto/__tests__/JwsService.test.ts b/packages/core/src/crypto/__tests__/JwsService.test.ts
index d36f402bb6..834d9855cc 100644
--- a/packages/core/src/crypto/__tests__/JwsService.test.ts
+++ b/packages/core/src/crypto/__tests__/JwsService.test.ts
@@ -2,7 +2,7 @@ import type { Wallet } from '@aries-framework/core'
 
 import { getAgentConfig } from '../../../tests/helpers'
 import { DidKey, KeyType } from '../../modules/dids'
-import { JsonEncoder } from '../../utils'
+import { Buffer, JsonEncoder } from '../../utils'
 import { IndyWallet } from '../../wallet/IndyWallet'
 import { JwsService } from '../JwsService'
 
@@ -67,6 +67,7 @@ describe('JwsService', () => {
       expect(isValid).toBe(true)
       expect(signerVerkeys).toEqual([didJwsz6Mkf.VERKEY, didJwsz6Mkv.VERKEY])
     })
+
     it('returns false if the jws signature does not match the payload', async () => {
       const payload = JsonEncoder.toBuffer({ ...didJwsz6Mkf.DATA_JSON, did: 'another_did' })
 
@@ -78,5 +79,14 @@ describe('JwsService', () => {
       expect(isValid).toBe(false)
       expect(signerVerkeys).toMatchObject([])
     })
+
+    it('throws an error if the jws signatures array does not contain a JWS', async () => {
+      await expect(
+        jwsService.verifyJws({
+          payload: new Buffer([]),
+          jws: { signatures: [] },
+        })
+      ).rejects.toThrowError('Unable to verify JWS: No entries in JWS signatures array.')
+    })
   })
 })