tls: handle empty cert in checkServerIndentity

This resolves joyent/node#9272. `tlsSocket.getPeerCertificate` will
return an empty object when the peer does not provide a certificate,
but, prior to this, when the certificate is empty, `checkServerIdentity`
would throw because the `subject` wasn't present on the cert.
`checkServerIdentity` must return an error, not throw one, so this
returns an error when the cert is empty instead of throwing
a `TypeError`.

PR-URL: https://github.com/nodejs/node/pull/2343
Reviewed-By: Fedor Indutny <fedor@indutny.com>
Reviewed-By: Shigeki Ohtsu <ohtsu@iij.ad.jp>

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/tls.js b/lib/tls.js
index 714fdebfc07..0e22242bc47 100644
--- a/lib/tls.js
+++ b/lib/tls.js
@@ -151,7 +151,7 @@ exports.checkServerIdentity = function checkServerIdentity(host, cert) {
                            host,
                            ips.join(', '));
     }
-  } else {
+  } else if (cert.subject) {
     // Transform hostname to canonical form
     if (!/\.$/.test(host)) host += '.';
 
@@ -204,6 +204,8 @@ exports.checkServerIdentity = function checkServerIdentity(host, cert) {
                              cert.subject.CN);
       }
     }
+  } else {
+    reason = 'Cert is empty';
   }
 
   if (!valid) {