Fix BigInteger.modInverse DoS in shipped bundles

Author: Kr0emer

npm/test/t_biginteger.js

@@ -0,0 +1,24 @@
+var assert = require('assert');
+var path = require('path');
+var spawnSync = require('child_process').spawnSync;
+
+describe("BigInteger", function() {
+    it('modInverse(0, odd) should return 0 without hanging', function() {
+        var childCode = [
+            "var rs = require('./lib/jsrsasign.js');",
+            "var a = new rs.BigInteger('0', 10);",
+            "var m = new rs.BigInteger('9', 10);",
+            "process.stdout.write(a.modInverse(m).toString(10));"
+        ].join('\n');
+
+        var result = spawnSync(process.execPath, ['-e', childCode], {
+            cwd: path.resolve(__dirname, '..'),
+            encoding: 'utf8',
+            timeout: 1500
+        });
+
+        assert.notEqual(result.error && result.error.code, 'ETIMEDOUT');
+        assert.equal(result.status, 0);
+        assert.equal(result.stdout, '0');
+    });
+});