* lisp/net/network-stream.el (network-stream-open-starttls):

Check that response to the starttls-command is non-nil.

Fixes: debbugs:13706

2 files changed, 8 insertions, 2 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 4a328a749bc..735ddd25369 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2013-02-16  Didier Verna  <didier@didierverna.net>
+
+        * net/network-stream.el (network-stream-open-starttls):
+        Check that response to the starttls-command is non-nil.  (Bug#13706)
+
 2013-02-14  Glenn Morris  <rgm@gnu.org>
 
         * emacs-lisp/easy-mmode.el (define-minor-mode): Doc fix.
diff --git a/lisp/net/network-stream.el b/lisp/net/network-stream.el
index 8cf9ec67e53..fd21997ba28 100644
--- a/lisp/net/network-stream.el
+++ b/lisp/net/network-stream.el
@@ -262,8 +262,9 @@ STARTTLS upgrades even if Emacs doesn't have built-in TLS functionality.
         ;; EHLO for SMTP.
         (when (plist-get parameters :always-query-capabilities)
           (network-stream-command stream capability-command eo-capa)))
-      (when (string-match success-string
-                          (network-stream-command stream starttls-command eoc))
+      (when (let ((response
+                   (network-stream-command stream starttls-command eoc)))
+              (and response (string-match success-string response)))
         ;; The server said it was OK to begin STARTTLS negotiations.
         (if builtin-starttls
             (let ((cert (network-stream-certificate host service parameters)))