I think I've found the problem:
Quoting from the last patch:

From: Ralph Boehme <s...@samba.org>
Date: Fri, 8 Oct 2021 12:33:16 +0200
Subject: [PATCH 138/284] CVE-2020-25717: s3:auth: remove fallbacks in
 smb_getpwnam()

So far we tried getpwnam("DOMAIN\account") first and
always did a fallback to getpwnam("account") completely
ignoring the domain part, this just causes problems
as we mix "DOMAIN1\account", "DOMAIN2\account",
and "account"!

As we require a running winbindd for domain member setups
we should no longer do a fallback to just "account" for
users served by winbindd!

For users of the local SAM don't use this code path,
as check_sam_security() doesn't call check_account().

The only case where smb_getpwnam("account") happens is
when map_username() via ("username map [script]")  mapped
"DOMAIN\account" to something without '\', but that is
explicitly desired by the admin.

-- end quote ---

So I've configured the smb.conf with:
username map script = /export/sbin/remove_domain.pl

to strip the domain from the username

This is a very basic perl script ( DONT USE THIS )

#!/usr/bin/perl -w

$username=$ARGV[0];
chomp $username;

if ($username =~ /^LABTA\\([a-zA-Z0-9\-]+)$/ ){
    $username = $1;
    print "$username\n";
}


With this configuration the 4.7.6+dfsg~ubuntu-0ubuntu2.26 starts to work.






** CVE added: https://cve.mitre.org/cgi-bin/cvename.cgi?name=2020-25717

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1954342

Title:
  Client authentication error "Failed to convert SID ... to a PID"

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/samba/+bug/1954342/+subscriptions


-- 
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to