Reduce privileges in systemd.service #119
Open
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This commit hardens the dnsconfd systemd service. dnsconfd and its Unbound backend are often used in security-conscious environments, such as for stable DNS over TLS and local DNSSEC validation. For example, the secureblue project, a derivative of Fedora Atomic, recently switched its users to dnsconfd by default. This is useful if the daemon is compromised somehow, but mostly improves auditabity. Rather than checking the SELinux policy, this gives the sysadmin a quick overview of the daemon's privileges (and for tools like `systemd-analyze security`). - Explicitly cap with no capabilities (already runs as `dnsconfd:dnsconfd` anyway) - Read-only filesystem except for `resolv.conf` and `/run/dnsconfd` - Removes legacy syscalls and IPC types - Reduces unnecessary kernel attack surface - Exploit mitigation (W^X, DoS, persistent privilege escalation)
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This commit hardens the dnsconfd systemd service. dnsconfd and its Unbound backend are often used in security-conscious environments, such as for stable DNS over TLS and local DNSSEC validation. For example, the secureblue project, a derivative of Fedora Atomic, recently switched its users to dnsconfd by default, where we use this hardening as an override.
This is useful if the daemon is compromised somehow, but mostly improves auditabity. Rather than checking the SELinux policy, this gives the sysadmin a quick overview of the daemon's privileges (and for tools like
systemd-analyze security).dnsconfd:dnsconfdanyway)resolv.confand/run/dnsconfd