Bug 2380156

Summary: Chromium %post script breaks SELinux policy
Product: [Fedora] Fedora Reporter: Marek Marczykowski <marmarek>
Component: chromiumAssignee: Than Ngo <than>
Status: CLOSED WORKSFORME QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: high Docs Contact:
Priority: unspecified    
Version: 42CC: pigpigman8686, spotrh, suraj.ghimire7, than, yaneti
Target Milestone: ---Keywords: SELinux
Target Release: ---Flags: than: needinfo? (marmarek)
Hardware: x86_64   
OS: Linux   
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Last Closed: 2025-12-10 11:23:49 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Marek Marczykowski 2025-07-15 14:24:43 UTC 
When both chromium and selinux-policy(-targeted) updates are part of the same transaction, the chromium %post script triggers loading half-assembled policy.
Especially, this loads newly installed policy, before its modules are rebuilt in %posttrans of selinux-policy-targeted (the `semodule -B` call), basically loading the policy without those modules (invalidating contexts defined there).

If a process involved in running the update has strict policy defined in a module, it gets denied most of the operations, basically interrupting the update. Interrupted update transaction is not a great outcome, to say mildly...
This happens when using Fedora 42 (41 too) on Qubes OS, but I believe it affects few other configurations too.

Reproducible: Always

Steps to Reproduce:
1. Get fedora-42-xfce template on Qubes OS
2. Install (older?) chromium package
3. Try installing updates that include both chromium and selinux-policy(-targeted) packages.
Actual Results:
Update crashes in the middle, just after updating chromium. Exact messages include:
```
[587333.301807] SELinux:  Converting 474 SID table entries...
[587333.301917] SELinux:  Context system_u:object_r:container_unit_file_t:s0 became invalid (unmapped).
[587333.302066] SELinux:  Context system_u:object_r:qubes_qubesdb_daemon_exec_t:s0 became invalid (unmapped).
[587333.302101] SELinux:  Context system_u:system_r:qubes_qubesdb_daemon_t:s0 became invalid (unmapped).
[587333.302141] SELinux:  Context system_u:object_r:qubes_var_run_t:s0 became invalid (unmapped).
[587333.302168] SELinux:  Context system_u:object_r:qubes_qubesdb_socket_t:s0 became invalid (unmapped).
[587333.302386] SELinux:  Context system_u:object_r:container_runtime_exec_t:s0 became invalid (unmapped).
[587333.303044] SELinux:  Context system_u:system_r:container_runtime_t:s0 became invalid (unmapped).
[587333.303075] SELinux:  Context system_u:object_r:container_var_run_t:s0 became invalid (unmapped).
[587333.303110] SELinux:  Context system_u:object_r:qubes_meminfo_writer_exec_t:s0 became invalid (unmapped).
[587333.303135] SELinux:  Context system_u:system_r:qubes_meminfo_writer_t:s0 became invalid (unmapped).
[587333.303162] SELinux:  Context system_u:object_r:qubes_meminfo_writer_var_run_t:s0 became invalid (unmapped).
[587333.303367] SELinux:  Context system_u:object_r:qubes_qrexec_agent_exec_t:s0 became invalid (unmapped).
[587333.303454] SELinux:  Context system_u:object_r:qubes_qrexec_socket_t:s0 became invalid (unmapped).
[587333.303650] SELinux:  Context system_u:system_r:qubes_qubesdb_daemon_t:s0-s0:c0.c1023 became invalid (unmapped).
[587333.303760] SELinux:  Context unconfined_u:object_r:qubes_var_run_t:s0 became invalid (unmapped).
[587333.309880] SELinux:  policy capability network_peer_controls=1
[587333.309906] SELinux:  policy capability open_perms=1
[587333.309920] SELinux:  policy capability extended_socket_class=1
[587333.309944] SELinux:  policy capability always_check_network=0
[587333.309960] SELinux:  policy capability cgroup_seclabel=1
[587333.309974] SELinux:  policy capability nnp_nosuid_transition=1
[587333.309994] SELinux:  policy capability genfs_seclabel_symlinks=1
[587333.310010] SELinux:  policy capability ioctl_skip_cloexec=0
[587333.310028] SELinux:  policy capability userspace_initial_context=0
```

Expected Results:
No crash, policy gets loaded only after it's complete (in the %posttrans, or wherever selinux-policy-targeted package decides it).

Additional Information:
References to Qubes OS reports:
- https://forum.qubes-os.org/t/update-borked-a-fedora-template/34788/37
- https://github.com/QubesOS/qubes-issues/issues/10054
Comment 1 Than Ngo 2025-07-22 09:54:20 UTC 
I tried to reproduce your problem by installing updates to the new selinux-policy(-targeted) packages created for testing purposes, as well as Chromium, and could not find any problem. It just works for me

Maybe it's a bug in QubesOS?
Comment 2 Marek Marczykowski 2025-08-01 13:48:45 UTC 
It's about transient state during update, services affected by it will have all operations denied (due to the policy being loaded without modules).
I've made a reproducer, let me attach it here.

Usage:
1. Get a system with updates for selinux-policy and chromium pending (Fedora live image is okay).
2. Build selinux-repro.spec. When installing build deps, be careful to not update selinux-policy just yet (I simply use --disablerepo=updates on live image)
3. Install selinux-repro and selinux-repro-selinux
4. Start selinux-repro service
5. Now update selinux-policy and chromium in a single transaction.
6. Observe that selinux-repro service crashed, see audit log for selinux denials
Comment 3 Marek Marczykowski 2025-08-01 13:49:20 UTC 
Created attachment 2102313 [details]
Reproducer
Comment 4 Than Ngo 2025-11-04 13:37:25 UTC 
Could you please try new chromium-142.0.7444.59 ? It's submitted as update in https://bodhi.fedoraproject.org/updates/FEDORA-2025-7c0b3fa81f

  sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2025-7c0b3fa81f

Thank you!
Comment 5 Than Ngo 2025-12-10 11:23:49 UTC 
CLosing it as i cannot reproduce it here.