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Bug 1822133 - Fix GSS-SPNEGO in TLS with maxssf=0 to work against Windows servers
Summary: Fix GSS-SPNEGO in TLS with maxssf=0 to work against Windows servers
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: cyrus-sasl
Version: 8.3
Hardware: Unspecified
OS: Unspecified
high
medium
Target Milestone: rc
: 8.3
Assignee: Simo Sorce
QA Contact: Ivan Nikolchev
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2020-04-08 10:47 UTC by Isaac Boukris
Modified: 2021-05-03 07:45 UTC (History)
1 user (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Cause: Windows servers do not allow seal/sign when over TLS, so we need a way to indicate not to negotiate them. While setting maxssf=0 works for GSSAPI, it doesn't for GSS-SPENGO. Consequence: Authentication against Windows services over a TLS channel and using the GSs-SPNEGO SASL mechanism can fail. Fix: Add support in cyrus-sasl to correctly handle maxssf=0 which will allow GSS-SPNEGO authentication to complete without failing. Result: Authentication against Windows Servers with GSS-SPNEGO over a TLS channel now works correctly.
Clone Of:
Environment:
Last Closed: 2020-11-04 01:47:40 UTC
Type: Bug
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)
Patch to enable a max_ssf of 0 (3.71 KB, patch)
2020-04-08 17:09 UTC, Simo Sorce 		no flags Details | Diff
Show Obsolete (1) View All


Links
System ID Private Priority Status Summary Last Updated
Github cyrusimap cyrus-sasl pull 603 0 None open Allow GSS-SPNEGO to negotiate a ssf of 0 2020-11-26 20:26:42 UTC
Red Hat Bugzilla 1589410 0 unspecified CLOSED In Fedora 28+ I can't authenticate using gssapi (kerberos ticket) to Windows AD when TLS 2021-04-26 00:26:34 UTC
Red Hat Product Errata RHSA-2020:4497 0 None None None 2020-11-04 01:47:50 UTC

Internal Links: 1589410

Description Isaac Boukris 2020-04-08 10:47:06 UTC 
Description of problem:

Windows servers do not allow seal/sign when over TLS, so we need a way to indicate not to negotiate them. While setting maxssf=0 works for GSSAPI, it doesn't for GSS-SPENGO.


How reproducible:

ldapsearch -h adc.acme.com -b dc=acme,dc=com cn=isaac -Y "GSS-SPNEGO" -N -ZZ -O
maxssf=0


Additional info:

Simo had posted a wip patch on the team list (works for me).
Comment 1 Simo Sorce 2020-04-08 17:09:43 UTC 
Created attachment 1677313 [details]
Patch to enable a max_ssf of 0
Comment 2 Simo Sorce 2020-04-16 15:58:23 UTC 
PR posted upstream
Comment 9 errata-xmlrpc 2020-11-04 01:47:40 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (Moderate: cyrus-sasl security, bug fix, and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2020:4497
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