RSA: backport macdabby's changes

phpseclib/Crypt/RSA.php

@@ -1786,7 +1786,7 @@ class Crypt_RSA
     function setPrivateKey($key = false, $type = false)
     {
         if ($key === false && !empty($this->publicExponent)) {
-            unset($this->publicExponent);
+            $this->publicExponent = false;
             return true;
         }
 
@@ -1794,7 +1794,7 @@ class Crypt_RSA
         if (!$rsa->loadKey($key, $type)) {
             return false;
         }
-        unset($rsa->publicExponent);
+        $rsa->publicExponent = false;
 
         // don't overwrite the old key if the new key is invalid
         $this->loadKey($rsa);

tests/Unit/Crypt/RSA/LoadKeyTest.php

@@ -345,4 +345,38 @@ Z2sKniRCcDT1ZP4=
 
         $this->assertTrue($result);
     }
+
+    /**
+     * @group github960
+     */
+    public function testSetLoad()
+    {
+        $key = 'PuTTY-User-Key-File-2: ssh-rsa
+Encryption: aes256-cbc
+Comment: phpseclib-generated-key
+Public-Lines: 4
+AAAAB3NzaC1yc2EAAAADAQABAAAAgQCqGKukO1De7zhZj6+H0qtjTkVxwTCpvKe4
+eCZ0FPqri0cb2JZfXJ/DgYSF6vUpwmJG8wVQZKjeGcjDOL5UlsuusFncCzWBQ7RK
+NUSesmQRMSGkVb1/3j+skZ6UtW+5u09lHNsj6tQ51s1SPrCBkedbNf0Tp0GbMJDy
+R4e9T04ZZw==
+Private-Lines: 8
+llx04QMegql0/nE5RvcJSrGrodxt6ytuv/JX2caeZBUyQwQc2WBNYagLHyHPM9jI
+9OUWz59FLhjFXZMDNMoUXxVmjwQpOAaVPYNxxFM9AF6/NXFji64K7huD9n4A+kLn
+sHwMLWPR5a/tZA0r05DZNz9ULA3mQu7Hz4EQ8ifu3uTPJuTmL51x6RmudYKysb20
+fM8VzC3ukvzzRh0pujUVTr/yQdmciASVFnZlt4xQy+ZEOVUAOfwjd//AFfXTvk6x
+7A45rNlU/uicHwLgoY1APvRHCFxw7F+uVW5L4mSX7NNzqBKkZ+1qpQTAfQvIfEIb
+444+CXsgIyOpqt6VxJH2u6elAtE1wau3YaFR8Alm8m97rFYzRi3oDP5NZYkTCWSV
+EOpSeghXSs7IilJu8I6/sB1w5dakdeBSFkIynrlFXkO0uUw+QJJWjxY8SypzgIuP
+DzduF6XsQrCyo6dnIpGQCQ==
+Private-MAC: 35134b7434bf828b21404099861d455e660e8740';
+
+        $rsa = new Crypt_RSA();
+        $rsa->setPrivateKey($key);
+        $rsa->loadKey($key);
+
+        $rsa = new Crypt_RSA();
+        $rsa->loadKey($key);
+        $rsa->setPrivateKey();
+        $rsa->loadKey($rsa);
+    }
 }