User talk:Mhonek

Switch OpenLDAP from NSS to OpenSSL

Overview

Currently, OpenLDAP in Fedora is compiled with NSS for cypto. This document describes a way to let the OpenLDAP be compiled with OpenSSL, instead.

Reasons

OpenLDAP in Fedora is has been compiled with NSS for crypto for several years now. Support layer for NSS was added back in 2008 but the OpenLDAP upstream ceased to keep it up to date since 2014. Reasons for keeping OpenLDAP compiled with NSS was to make it work with some other packages (esp. 389DS) seamlessly. Fixing and keeping downstream patches has become a burden, thus it was decided to switch to OpenSSL, instead.

Dependents

389DS

Upstream patch that mirrors certificates to PEM files so that OpenSSL-built OpenLDAP library may be used, is supported since version 389-ds-base-1.3.5.

See the design document.

FreeIPA

BuildRequires: openldap-devel
Requires: openldap-clients

SSSD

BuildRequires: openldap-devel

dhcpd

BuildRequires: openldap-devel

python-ldap

BuildRequires: openldap-devel

Uses OpenSSL for TLS, so maybe not a problem?

others

TODO

Schedule

Prerequisities

• Finish this design.
• Discuss with closely related teams (389DS - done, SSSD, FreeIPA).
• Reach out to the Fedora community with a request for comments, especialy those that Require or BuildRequire OpenLDAP.

Test Day

TODO

Fedora 26

• Land the OpenSSL-built OpenLDAP. This should include the #Interception code with X_MOZNSS_COMPATIBILITY set on by default.
• Include a deprecation warning.

Fedora 27

• Turn the #Interception code off by default, still being able to enable it with the X_MOZNSS_COMPATIBILITY.

Fedora 28

• Drop the #Interception code patching entirely. All packages should be already fully functional with OpenSSL-built OpenLDAP not supporting NSS-specific functionality.
• Drop the deprecation warning.

Implementation

The code handling possible NSS-specific configuration (#Interception code) should handle all possible use-cases (libldap, openldap-clients and openldap-servers packages). Briefly, the code should make usage of both, OpenSSL-specific and NSS-specific, configurations seamless with no more than setting the X_MOZNSS_COMPATIBILITY option on.

Build

Will build with ./configure --with-tls=openssl, dropping --with-tls=moznss. Also, NSS libs will be needed to be included so that the #Interception code works.

Interception code

Enabling

A yes/no options LDAP_OPT_X_MOZNSS_COMPATIBILITY (libldap), X_MOZNSS_COMPATIBILIY (ldap.conf, slapd.conf), and olcMozNSSCompatibility (slapd-config) may be used to explicitly set whether the #Interception code will be used.

Implementation

After parsing user options change these accordingly:

• keep CACERT as set
• if CACERTDIR is NSSDB then
  • if NSSDB is pin-protected then
    • unlock the DB using KEY
  • extract all CA certs to ca.pem
  • extract all CA certs from (DEFAULT_)MOZNSS_DIR environment variable to (default_)moznss_dir.pem
  • extract user cert and key to user.pem
  • get the randomly pre-generated DH params from NSSDB and put it into DHParamFile
  • update options so that they work for OpenSSL
• go on

Considerations

PEM files location

We should keep the NSSDB in place, while creating a directory with the same owner and permissions for storing the extracted PEM files. If the directory cannot be created, we should temporarily put these to a tempdir (in /tmp).

CRLCheck and CRLFile options

NSS uses CRLFILE option only, whereas OpenSSL uses CRLCHECK bool.

NSS still used

Even though temporarily, NSS library is still used possibly causing some (although few) troubles.

Testing

Areas

Interception code functionality

Basic self-signed ca cert and user cert/key

TODO

With self-signed cert chain

TODO

Regressions

TODO

Dependent packages' tests

TODO

Testing Day(s)

TODO

Pitfalls

Downgrade

Will not be supported automatically. We should provide steps how to revert to NSSDB having OpenSSL-like configuration in place.

Mixed configuration options have undefined behaviour

If both, OpenSSL-like and NSS-like, configurations are used for various configuration parameters at the same time then the behaviour SHOULD not be destructive but it is undefined.