[Samba] Stymied with samba vs openldap SSL ("Failed to issue the StartTLS instruction...")

Graham Allan allan at physics.umn.edu
Wed Jan 6 20:56:57 UTC 2016

On 01/06/2016 01:34 PM, Lee Brown wrote:
> On Wed, Jan 6, 2016 at 10:36 AM, Graham Allan <allan at physics.umn.edu
> <mailto:allan at physics.umn.edu>> wrote:
>     On 01/06/2016 09:53 AM, Graham Allan wrote:
>         The packet dump is a good idea. I get the same failure using
>         straight
>         SSL to port 636, but wireshark might be able to decode any StartTLS
>         negotiation attempt on the default port. Failing that I guess I'll
>         resort to running smbd in gdb...
>     tshark tells me the (smbd) client sends a decrypt error (TLS alert
>     code 51) to the ldap server after receiving the certificate, while
>     the working "ldapsearch -ZZ" moves on to client key exchange etc.
>     Puzzling, it doesn't seem like a certificate validation error, I'd
>     expect that to result in something like codes 42-48.
> I'd be very interested to see how you troubleshoot this.  I'm running
> FreeBSD 10.1, samba 4.2.3, but I don't use openldap as the backend,
> samba is my LDAP now as it does Active Directory.  I've found SSL to be
> incredibly hard to troubleshoot, especially when client certs get
> involved as it gets hard to determine if the problem is on the server
> side not liking the client cert, or the client side not liking the
> server cert.  In some cases I've had to bundle the entire chain in a
> single file, while others I've had to point to a directory of certs.

gdb didn't give me much new, though for the record, it needed a couple 
of things to be usable: (1) install newer gdb from ports, and (2) build 
samba with --disable-pie

What I got from that was ldap_start_tls_s (ldap_struct, NULL, NULL) in 
smb_ldap_start_tls is returning -11 (LDAP_CONNECT_ERROR), which doesn't 
really help.

Maximum debugging on the ldap server gave me:
connection_read(3): TLS accept failure error=-1 id=1042, closing
conn=1042 fd=3 closed (TLS negotiation failure)

I'm out of ideas for now, other than maybe trying one of the openldap lists!


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