Bug 2160391
| Summary: | SELinux is preventing systemd from using LoadCredentials | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 9 | Reporter: | Nikita Uvarov <nuvarov> |
| Component: | selinux-policy | Assignee: | Nikola Knazekova <nknazeko> |
| Status: | CLOSED ERRATA | QA Contact: | Milos Malik <mmalik> |
| Severity: | low | Docs Contact: | |
| Priority: | medium | ||
| Version: | CentOS Stream | CC: | bstinson, jwboyer, lvrabec, mmalik, sujagtap, zpytela |
| Target Milestone: | rc | Keywords: | Triaged |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | selinux-policy-38.1.5-1.el9 | Doc Type: | Bug Fix |
| Doc Text: |
Cause: systemd-creds apparently runs in a chroot where /dev/shm is backed by ramfs (ramfs_t) instead of the usual tmpfs, which is not allowed in the policy
Consequence: SELinux is preventing systemd from using LoadCredentials
Fix: Reuse tmpfs_t also for the ramfs filesystem
Result: No SELinux denials
|
Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | 2023-05-09 08:17:16 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
I believe this BZ is a RHEL-9 variant of BZ#2096857. I thinks these two commits are needed: 021025430 Allow systemd-resolved watch tmpfs directories 8e908b8d9 Reuse tmpfs_t also for the ramfs filesystem and there is one pr pending for cases when sockets are used. *** Bug 2160933 has been marked as a duplicate of this bug. *** 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 (selinux-policy 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/RHBA-2023:2483 |
Description of problem: Current SELinux policies doesn't allow new systemd credentials feature. E.g. running a command like this: ``` sudo systemd-run -P --wait -p LoadCredential=abc:/etc/hosts systemd-creds cat abc ``` Results in: run-u11509.service: Failed to set up credentials: Protocol error run-u11509.service: Failed at step CREDENTIALS spawning /bin/systemd-creds: Protocol error run-u11509.service: Main process exited, code=exited, status=243/CREDENTIALS run-u11509.service: Failed with result 'exit-code'. And audit.log: type=PROCTITLE msg=audit(12/06/2022 14:32:29.129:410) : proctitle=(sd-mkdcreds) type=SYSCALL msg=audit(12/06/2022 14:32:29.129:410) : arch=x86_64 syscall=openat success=no exit=EACCES(Permission denied) a0=0x3 a1=0x55a11385ef90 a2=O_RDWR|O_CREAT|O_EXCL|O_NOCTTY|O_NOFOLLOW|O_CLOEXEC a3=0x180 items=0 ppid=3368570 pid=3368571 auid=unset uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=(none) ses=unset comm=(sd-mkdcreds) exe=/usr/lib/systemd/systemd subj=system_u:system_r:init_t:s0 key=(null) type=AVC msg=audit(12/06/2022 14:32:29.129:410) : avc: denied { read write open } for pid=3368571 comm=(sd-mkdcreds) path=/dev/shm/.#cred8d2badcefa7a5141 dev="ramfs" ino=365308391 scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:ramfs_t:s0 tclass=file permissive=0 This seems to be because selinux forbids systemd process to create ramfs files. Adding such permission with semodule containing the following permissions fixes the problem: allow init_t ramfs_t:file { create open read rename setattr write }; Version-Release number of selected component (if applicable): CentOS Stream 9 selinux-policy-targeted: 38.1.3 How reproducible: Everytime Steps to Reproduce: 1. Make sure selinux is enabled 2. sudo systemd-run -P --wait -p LoadCredential=abc:/etc/hosts systemd-creds cat abc Actual results: Main processes terminated with: code=exited/status=243 Expected results: Contents of /etc/hosts file Additional info: Compiling and installing semodule with the following permissions fixes the issue: allow init_t ramfs_t:file { create open read rename setattr write };