[FIX] base: timeout on smtp connections

Currently when connecting to a smtp server, if no response is returned
and no error is raised, the `SMTP()` instantiation method never ends.

This PR is inspired by 54a477d797 related to `fetchmail()`.
Possibly, a better way exists but it has to change some methods
signatures.

Closes #24877
opw-1851030

openerp/addons/base/ir/ir_mail_server.py

@@ -28,6 +28,8 @@ from openerp.loglevels import ustr
 _logger = logging.getLogger(__name__)
 _test_logger = logging.getLogger('openerp.tests')
 
+SMTP_TIMEOUT = 60
+
 
 class MailDeliveryException(except_orm):
     """Specific exception subclass for mail delivery errors"""
@@ -215,9 +217,9 @@ class ir_mail_server(osv.osv):
             if not 'SMTP_SSL' in smtplib.__all__:
                 raise UserError(_("Your OpenERP Server does not support SMTP-over-SSL. You could use STARTTLS instead."
                                     "If SSL is needed, an upgrade to Python 2.6 on the server-side should do the trick."))
-            connection = smtplib.SMTP_SSL(host, port)
+            connection = smtplib.SMTP_SSL(host, port, timeout=SMTP_TIMEOUT)
         else:
-            connection = smtplib.SMTP(host, port)
+            connection = smtplib.SMTP(host, port, timeout=SMTP_TIMEOUT)
         connection.set_debuglevel(smtp_debug)
         if encryption == 'starttls':
             # starttls() will perform ehlo() if needed first