[Bug 1576799] Re: Regression: 2:4.3.8+dfsg-0ubuntu0.14.04.2 Failed to Issue the StartTLS instruction

[Marc Deslauriers]

I don't think this is a regression. The Samba security update is now
more strict when validating TLS certs.

I'm not sure why it's using the ip address instead of the hostname,
that's probably a configuration issue.

If you want a workaround, you can try adjusting cert checking, see:

https://wiki.samba.org/index.php/Samba_4.3_Features_added/changed#tls_verify_peer_.28G.29

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Title:
  Regression: 2:4.3.8+dfsg-0ubuntu0.14.04.2 Failed to Issue the StartTLS
  instruction

Status in samba package in Ubuntu:
  New

Bug description:
  With the recent samba upgrade to 2:4.3.8+dfsg-0ubuntu0.14.04.2, we
  were seeing regression with authentication:

  /var/log/syslog
  Apr 28 17:45:52 hostname winbindd[769]: [2016/04/28 17:45:52.415470,  0] ../source3/lib/smbldap.c:575(smbldap_start_tls)
  Apr 28 17:45:52 hostname winbindd[769]:   Failed to issue the StartTLS instruction: Connect error
  Apr 28 17:45:52 hostname winbindd[769]: [2016/04/28 17:45:52.898408,  0] ../source3/lib/smbldap.c:575(smbldap_start_tls)
  Apr 28 17:45:52 hostname winbindd[769]:   Failed to issue the StartTLS instruction: Connect error

  
  We had to rollback to: 2:4.1.6+dfsg-1ubuntu2.14.04.13 and everything worked again.

  Here's a basic samba config that reproduces the issue:

  Perfectly reproducible with this:
    realm = AD.DOMAIN.COM
    security = ads
    ldap ssl = start_tls
    ldap ssl ads = yes

  [LDAP] TLS: hostname (172.12.12.12) does not match common name in certificate (hostname).
  [LDAP] ldap_err2string
  Failed to issue the StartTLS instruction: Connect error

  Samba seems to construct the LDAP URL with the IP of the AD controller
  in it instead of the hostname and then because our ldap.conf requires
  it, the server cert validation fails

  Please let me know if there are any other logs I can provide

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