RHEL-21049: [1.28] Fix issue with registration using gsd-subman

[jirihnidek]

• Backport to 1.28 branch. Original PR: RHEL-15110: Fix issue with registration using gsd-subman #3350
• Original commits:
  • ba1e0e4
  • bc33776
• We were too agresive, when we fixed CVE in this PR:
  2225443: [1.28] Hotfix of D-Bus policy #3318
• It is still safe to allow non-root user to create abstract
  socket using Start() on interface com.redhat.RHSM1.RegisterServer
  and destroy it later using Stop(). This abstract socket
  could be later used by root user for calling e.g. Register()
  on interface com.redhat.RHSM1.Register. This is way how
  it works for gsd-subman (run by non-root user) and
  gsd-subman-helper (run by root user).
• When some application starts RegisterServer using Start(),
  then it returns address. When this method is called multiple
  times and RegisterServer is still running, then the same
  address is returned. It means, when user starts multiple
  applications, then all of these applications should be able
  to use the same address to keep backward compatibility.
  The RegisterServer should be terminated only in the case,
  when the last application call Stop() and there is no running
  process using this RegisterServer.
• This change does not allow to stop RegisterServer by some other
  user or application using Stop() method, when RegisterServer
  is still needed.
• Non-root user can stop the RegisterServer only in the situation,
  when it is not needed by any application.
• Implementation of Stop() method did not return anything explicitly,
  but the D-Bus method was designed to return boolean value. Thus,
  None object was interpreted as "False" value. It was fixed and it
  returns "True", when it was really stopped and it return "False",
  when it was not possible to stop it, because some application
  still uses RegisterServer.
• It looks like that there was probably intention to use similar
  approach, but it has never been finished.
• Modified some unit tests

[github-actions]

Coverage (computed on CentOS Stream 9) •

File	Stmts	Miss	Cover	Missing
rhsmlib/dbus
dbus_utils.py	102	66	35%	38–44, 51–52, 54–57, 61–63, 65, 72–73, 75–79, 85–89, 96–97, 99–102, 104, 110, 114, 119, 121, 123, 125, 127, 135, 137, 139, 141, 144, 152, 162, 189, 193, 205, 207, 209, 211–213, 215–216, 218–219, 224–227
server.py	209	122	41%	55–56, 68, 71–72, 74–79, 81–90, 92–93, 95–100, 102–104, 106–125, 127, 131, 135, 139, 143, 148, 155, 159, 166–174, 177–179, 186–188, 190, 198, 201, 203, 210–211, 213, 227, 230–233, 245–249, 272, 277–281, 285–289, 291–292, 294, 301, 340–341, 349–355, 357–359, 363, 386–387
rhsmlib/dbus/objects
register.py	197	15	92%	97–98, 116, 119, 131, 134, 196, 198, 206, 216, 220, 223, 253, 344, 353
TOTAL	22293	9260	58%

Tests	Skipped	Failures	Errors	Time
2368	11 💤	0 ❌	0 🔥	42.196s ⏱️

[jirihnidek]

Tested on RHEL8 workstation. Registration/Unregistration works with gsd-subman as expected.

[m-horky]

LGTM. The patch matches the original one and I've verified the (un)registration GUI behaves as expected.