From b7d28d3135fa298d693aa22d2f1713054c5b0751 Mon Sep 17 00:00:00 2001
From: Alena Khineika <alena.khineika@gmail.com>
Date: Fri, 26 Jan 2024 21:51:14 +0100
Subject: [PATCH] fix(NODE-5609): node driver omits base64 padding in
 sasl-continue command (#3975)

---
 src/cmap/auth/scram.ts                      |  2 +-
 test/unit/assorted/scram_iterations.test.ts | 33 +++++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/src/cmap/auth/scram.ts b/src/cmap/auth/scram.ts
index 53bbf531eb..ba18e0f5c7 100644
--- a/src/cmap/auth/scram.ts
+++ b/src/cmap/auth/scram.ts
@@ -212,7 +212,7 @@ function parsePayload(payload: Binary) {
   const dict: Document = {};
   const parts = payloadStr.split(',');
   for (let i = 0; i < parts.length; i++) {
-    const valueParts = parts[i].split('=');
+    const valueParts = (parts[i].match(/^([^=]*)=(.*)$/) ?? []).slice(1);
     dict[valueParts[0]] = valueParts[1];
   }
   return dict;
diff --git a/test/unit/assorted/scram_iterations.test.ts b/test/unit/assorted/scram_iterations.test.ts
index a08274781a..106550ae10 100644
--- a/test/unit/assorted/scram_iterations.test.ts
+++ b/test/unit/assorted/scram_iterations.test.ts
@@ -129,4 +129,37 @@ describe('SCRAM Iterations Tests', function () {
       .to.have.property('message')
       .that.matches(/connection(.+)closed/);
   });
+
+  it('should preserve trailing "=" from saslStart responses that are passed to saslContinue', async function () {
+    const credentials = new MongoCredentials({
+      mechanism: 'DEFAULT',
+      source: 'db',
+      username: 'user',
+      password: 'pencil',
+      mechanismProperties: {}
+    });
+    let payload;
+    client.s.options.credentials = credentials;
+
+    server.setMessageHandler(request => {
+      const doc = request.document;
+      if (isHello(doc)) {
+        return request.reply(Object.assign({}, mock.HELLO));
+      } else if (doc.saslStart) {
+        return request.reply({
+          ok: 1,
+          done: false,
+          payload: Buffer.from(
+            'n=__system,r=r7RuW8nC89hmrlIPSpatiEGnZGkuGcsq,r=r7RuW8nC89hmrlIPSpatiEGnZGkuGcsquPuvfddlU3NavdfJxv/XKg==,s=b7rCae/2BRjlcsn93RoUOfqtiwaf0nrXvSKLdQ==,i=15000'
+          )
+        });
+      } else if (doc.saslContinue) {
+        payload = doc.payload.toString('utf8');
+        request.connection.destroy();
+      }
+    });
+
+    await client.connect().catch(error => error);
+    expect(payload).to.includes('r=r7RuW8nC89hmrlIPSpatiEGnZGkuGcsquPuvfddlU3NavdfJxv/XKg==');
+  });
 });