New subject: [sssd PR#717][comment] NSS: Avoid changing the memory cache ownership away from the sssd user (sssd-1-16 backport)

17 Dec 2018


      URL: https://github.com/SSSD/sssd/pull/717
Author: jhrozek
 Title: #717: NSS: Avoid changing the memory cache ownership away from the sssd user (sssd-1-16 backport)
Action: opened
PR body:
"""
Resolves: https://pagure.io/SSSD/sssd/issue/3890
In case SSSD is compiled --with-sssd-user but run as root (which is the 
default on RHEL and derivatives), then the memory cache will be owned by 
the user that sssd_nss runs as, so root.
This conflicts with the packaging which specifies sssd.sssd as the owner.
And in turn, this means that users can't reliably assess the package
integrity using rpm -V.
This patch makes sure that the memory cache files are chowned to sssd.sssd 
even if the nss responder runs as root.
Also, this patch changes the sssd_nss responder so that is becomes a member 
of the supplementary sssd group. Even though in traditional UNIX sense, a
process running as root could write to a file owned by sssd:sssd, with 
SELinux enforcing mode this becomes problematic as SELinux emits an error 
such as:
type=AVC msg=audit(1543524888.125:1495): avc:  denied  { fsetid } for 
pid=7706 comm="sssd_nss" capability=4  scontext=system_u:system_r:sssd_t:s0 
tcontext=system_u:system_r:sssd_t:s0 tclass=capability
To make it possible for the sssd_nss process to write to the files, the 
files are also made group-writable. The 'others' permission is still set to
read only.
Reviewed-by: Michal Židek mzidek@redhat.com
(cherry picked from commit 61e4ba58934b20a950255e05797aca25aadc1242)
"""
To pull the PR as Git branch:
git remote add ghsssd https://github.com/SSSD/sssd
git fetch ghsssd pull/717/head:pr717
git checkout pr717

[sssd PR#717][opened] NSS: Avoid changing the memory cache ownership away from the sssd user (sssd-1-16 backport)