Decode `challenge` when decoding client data

1 files changed, 7 insertions, 1 deletions

diff --git a/packages/server/src/helpers/decodeClientDataJSON.ts b/packages/server/src/helpers/decodeClientDataJSON.ts
index 1aeb9c9..0ff5dea 100644
--- a/packages/server/src/helpers/decodeClientDataJSON.ts
+++ b/packages/server/src/helpers/decodeClientDataJSON.ts
@@ -7,5 +7,11 @@ import asciiToBinary from './asciiToBinary';
  */
 export default function decodeClientDataJSON(data: string): ClientDataJSON {
   const toString = asciiToBinary(data);
-  return JSON.parse(toString);
+  const clientData: ClientDataJSON = JSON.parse(toString);
+
+  // `challenge` will be Base64-encoded here. Decode it for easier comparisons with what is provided
+  // as the expected value
+  clientData.challenge = Buffer.from(clientData.challenge, 'base64').toString('ascii');
+
+  return clientData;
 }