Issue #12000: When a SSL certificate has a subjectAltName without any

dNSName entry, ssl.match_hostname() should use the subject's commonName.
Patch by Nicolas Bareil.

1 files changed, 3 insertions, 2 deletions

diff --git a/Lib/ssl.py b/Lib/ssl.py
index 84aa6dc..e7c175f 100644
--- a/Lib/ssl.py
+++ b/Lib/ssl.py
@@ -122,8 +122,9 @@ def match_hostname(cert, hostname):
             if _dnsname_to_pat(value).match(hostname):
                 return
             dnsnames.append(value)
-    if not san:
-        # The subject is only checked when subjectAltName is empty
+    if not dnsnames:
+        # The subject is only checked when there is no dNSName entry
+        # in subjectAltName
         for sub in cert.get('subject', ()):
             for key, value in sub:
                 # XXX according to RFC 2818, the most specific Common Name