Bug 1917879
| Summary: | Cannot sudo passwordless from staff_u/sysadm_u when using pam_ssh_agent_auth | ||||||
|---|---|---|---|---|---|---|---|
| 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: | apeetham, lvrabec, mmalik, pkoncity, plautrba, ssekidde, zpytela | ||||
| 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 15:14:56 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 | ||||||
| Attachments: |
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Additional missing rules:
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
allow sudodomain user_tmp_t:sock_file { write getattr append open };
allow sudodomain ssh_agent_tmp_t:sock_file { write getattr append open };
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
Created attachment 1750851 [details]
SELinux denials gathered during testing of staff_u and sysadm_u users
I've submitted a Fedora PR to address the issue: https://github.com/fedora-selinux/selinux-policy/pull/976 To backport:
commit 901ac5314982f5600ef11691969b9af89aeba772
Author: Zdenek Pytela <zpytela>
Date: Mon Dec 20 14:21:33 2021 +0100
Allow userdomains use pam_ssh_agent_auth for passwordless sudo
The pam_ssh_agent_auth module can be used for granting permissions based
on SSH agent requests. When configured for using in the sudo pam module,
it requires permissions for sudodomain to use the user socket file and
stream connect to its corresponding userdomain.
Resolves: rhbz#1917879
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: After configuring pam_ssh_agent_auth to provide passwordless sudo through ssh agent, AVCs are preventing "sudo" from working: -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- allow staff_sudo_t staff_t:unix_stream_socket connectto; allow staff_sudo_t user_tmp_t:sock_file { getattr write }; allow sysadm_sudo_t sysadm_t:unix_stream_socket connectto; allow sysadm_sudo_t user_tmp_t:sock_file write; -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- More generally, what is missing are these rules: -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- allow staff_sudo_t staff_t:unix_stream_socket connectto; allow sysadm_sudo_t sysadm_t:unix_stream_socket connectto; allow auditadm_sudo_t auditadm_t:unix_stream_socket connectto; allow dbadm_sudo_t dbadm_t:unix_stream_socket connectto; allow secadm_sudo_t secadm_t:unix_stream_socket connectto; allow sudodomain user_tmp_t:sock_file { getattr write }; -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- Version-Release number of selected component (if applicable): selinux-policy-3.14.3-54.el8.noarch How reproducible: Always Steps to Reproduce: 1. Install pam_ssh_agent_auth -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- # yum -y install pam_ssh_agent_auth -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- 2. Configure passwordless sudo through ssh agent /etc/pam.d/sudo: -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- auth sufficient pam_ssh_agent_auth.so file=~/.ssh/authorized_keys ... -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- /etc/sudoers: -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- Defaults env_keep += "SSH_AUTH_SOCK" -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- 3. Create "staff" and "sysadm" users -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- # useradd -Z staff_u -G wheel staff # echo "pass" | passwd --stdin staff # useradd -Z sysadm_u -G wheel sysadm # echo "pass" | passwd --stdin sysadm -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- 4. Generate ssh key and install it -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- # ssh-keygen # ssh-copy-id staff@localhost # ssh-copy-id sysadm@localhost # semanage boolean -m ssh_sysadm_login --on -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- 5. Finally start ssh-agent, ssh and sudo from the account -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- # ssh-agent; ssh-add # ssh -A staff@localhost $ sudo -i -------- 8< ---------------- 8< ---------------- 8< ---------------- 8< -------- Actual results: [sudo] password for staff: Expected results: Password-less sudo