Bug 1943572
| Summary: | confined sysadm user cannot update a user's password using "sudo passwd ..." command | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 8 | Reporter: | Renaud Métrich <rmetrich> |
| Component: | selinux-policy | Assignee: | Zdenek Pytela <zpytela> |
| Status: | CLOSED ERRATA | QA Contact: | Milos Malik <mmalik> |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | 8.3 | CC: | lvrabec, mmalik, plautrba, ssekidde |
| Target Milestone: | rc | Keywords: | Triaged |
| Target Release: | 8.6 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | selinux-policy-3.14.3-86.el8 | Doc Type: | Bug Fix |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2022-05-10 15:14:58 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: | |||
| Bug Depends On: | |||
| Bug Blocks: | 1778780 | ||
I've submitted a Fedora PR to address the issue: https://github.com/fedora-selinux/selinux-policy/pull/976 To backport:
commit 3b826a9f34d86388fde3a07a9dcfeccdc762bafe
Author: Zdenek Pytela <zpytela>
Date: Mon Dec 20 11:47:29 2021 +0100
Allow sudodomains execute passwd in the passwd domain
When an unprivileged user in the sysadm_r role executes passwd
through sudo, it transitions into sysadm_sudo_t domain by default.
With this commit, the process transitions back to sysadm_t.
Resolves: rhbz#1943572
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-2022:1995 |
Description of problem: There are many cases where executing a command with sudo as a confined sysadm user doesn't work, usually most command executed as shown below: $ sudo <program> <args...> e.g. $ sudo passwd The root cause are missing contexts or transitions from "sysadm_sudo_t" (context of "sudo") to appropriate context (e.g. "passwd_t" through "passwd_exec_t" file). With time, engineering comes up with adding more rules for domains, but since customers use very customized configuration, the policy is always late. Last reported issue is with "passwd" when using cracklib database: When executing "sudo passwd", the cracklib database cannot be read because "passwd" command executes in the context of "sudo" (sysadm_sudo_t) instead of "passwd (passwd_t"). As shown in the example below: -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- type=PROCTITLE ... : proctitle=passwd <USERNAME> type=PATH ... : item=0 name=/usr/share/cracklib/pw_dict.pwd.gz ... mode=file,644 ouid=root ogid=root rdev=00:00 obj=system_u:object_r:crack_db_t:s0 ... type=SYSCALL ... : arch=x86_64 syscall=open success=no exit=EACCES(Permission denied) a0=0x7ffde70cf450 a1=O_RDONLY ... uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root ... comm=passwd exe=/usr/bin/passwd subj=sysadm_u:sysadm_r:sysadm_sudo_t:s0-s0:c0.c1023 ... type=AVC ... : avc: denied { read } for pid=13672 comm=passwd name=pw_dict.pwd.gz ... scontext=sysadm_u:sysadm_r:sysadm_sudo_t:s0-s0:c0.c1023 tcontext=system_u:object_r:crack_d _t:s0 tclass=file permissive=0 -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- Version-Release number of selected component (if applicable): RHEL8.3 policy, RHEL7.9 policy How reproducible: Always when using crack library. Additional info: We need to fix the policy again and again. Note that I filed a RFE against sudo to always use the "SELinux aware" code: BZ #1910077 Implementing this RFE would solve **ALL** "sudo <command>" issues.