Sanitize inputs

src/start-proxy.test.ts

@@ -80,3 +80,31 @@ test("getCredentials returns all credentials when no language specified", async
   );
   t.is(credentials.length, 3);
 });
+
+test("getCredentials throws an error when non-printable characters are used", async (t) => {
+    const invalidCredentials = [
+      { type: "nuget_feed", host: "1nuget.pkg.github.com", token: "abc\u0000" }, // Non-printable character in token
+      { type: "nuget_feed", host: "2nuget.pkg.github.com\u0001" }, // Non-printable character in host
+      { type: "nuget_feed", host: "3nuget.pkg.github.com", password: "ghi\u0002" }, // Non-printable character in password
+      { type: "nuget_feed", host: "4nuget.pkg.github.com", password: "ghi\x00" }, // Non-printable character in password
+    ];
+
+    for (const invalidCredential of invalidCredentials) {
+      const credentialsInput = Buffer.from(
+        JSON.stringify([invalidCredential]),
+      ).toString("base64");
+
+      t.throws(
+        () =>
+          startProxyExports.getCredentials(
+            getRunnerLogger(true),
+            undefined,
+            credentialsInput,
+            undefined,
+          ),
+        {
+          message: "Invalid credentials - fields must contain only printable characters",
+        },
+      );
+    }
+  });